TWI412843B - Optical compensation film, polarizing plate and liquid crystal display - Google Patents

Description

Optical compensation film, polarizing plate and liquid crystal display device

The present invention relates to a polarizing plate and a liquid crystal display device having an optically anisotropic layer containing a discotic compound. Further, the present invention relates to an optical compensation film having an optically anisotropic layer containing a discotic compound and a liquid crystal display device using the same.

The liquid crystal display device is generally composed of a liquid crystal cell, a polarizing element, and an optical compensation film (hysteresis value plate). In a transmissive liquid crystal display device, two polarizing elements are generally disposed on both sides of a liquid crystal cell, and one or two optical compensation films are disposed between the liquid crystal cell and the polarizing element. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, a piece of optical compensation film, and then one polarizing element are generally disposed. The liquid crystal cell is composed of a rod-like liquid crystal molecule, two substrates for encapsulating it, and an electrode layer for applying a voltage to the rod-like liquid crystal molecules. The liquid crystal cell system has been proposed to have a penetrating type of TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal, iron) depending on the alignment state of the rod-like liquid crystalline molecules. Electro-liquid crystal), OCB (Optically Compensatory Bend), STN (Supper Twisted Nematic), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), reflective type It is a variety of display modes like TN, HAN (Hybrid Aligned Nematic), and GH (Guest-Host).

In order to release the image or to enlarge the viewing angle, the optical compensation film is used in a wide variety of liquid crystal display devices. The optical compensation film has been an extended birefringent polymer film since the past. Further, in place of the optical compensation film film composed of the extended birefringent film, it is proposed to use an optical compensation film having an optically anisotropic layer formed of a low molecular or high molecular liquid crystalline compound on a transparent support. Since the liquid crystal compound has various kinds of alignment forms, the liquid crystal compound can be used to realize optical properties which cannot be obtained by the conventional extended birefringence polymer film. Further, a configuration in which a protective film and an optical compensation film are combined by adding a birefringence to a protective film of a polarizing plate is also proposed.

Among the LCDs, in particular, high-display grades are essential applications, and nematic liquid crystal molecules having a positive dielectric anisotropy are mainly used, and a nematic liquid crystal display device that is rotated by 90 degrees by a thin film transistor is used. Hereinafter, it is called TN mode). As an optical compensation film which expands the TN mode liquid crystal layer liquid crystal display cell viewing angle, the optical compensation film produced by fixing the disk-shaped compound in a mixed alignment is practical (for example, Patent No. 2587398). In this method, since the nematic liquid crystal cells composed of the rod-like liquid crystal are compensated by the disk-shaped compound, the incident light from the oblique direction can be compensated, and the viewing angle can be particularly enlarged. In this case, the compensation film composed of the disk-shaped compound is disposed on the two sides, the display surface side, and the back side of the backlight, with respect to the TN liquid crystal cells in which the rod-shaped molecules are aligned in the twisted alignment. Designing a disc-shaped compound alignment by applying a voltage, effectively compensating the black display, reducing the black transmittance in the up, down, left, and right directions, and expanding the viewing angle by applying a voltage. Azimuth direction.

The alignment state of the liquid crystal layer of the liquid crystal display device is optically compensated by a disk-shaped compound, and the viewing angle can be increased. However, in this compensation method, the viewing angle region (contrast viewing angle) at which the high contrast of the TN liquid crystal display device can be maintained is expanded, and the viewing angle compensation of the polarizing plate cannot be completely solved.

In the liquid crystal display device, a pair of polarizing plates are disposed above and below the liquid crystal layer to form an angle orthogonal to the absorption axis. Thereby, the transmittance of the front surface of the display device becomes black, and a high contrast image can be obtained. However, when the display device is viewed obliquely in this state, it is seen that the angles of the absorption axes of the upper and lower polarizing plates are formed at an angle larger than 90°, and light leakage is generated and the contrast is lowered. That is, although the TN mode has excellent display characteristics in the case of viewing from the front, the contrast is lowered when viewed from the oblique direction, and the inversion of the reversed brightness is caused by the tone display, etc., which has a so-called display characteristic deterioration. The viewing angle characteristics are strongly required to be improved. In particular, the market requirements for comparison are strong, and it is particularly strongly required that the contrast between the upper and lower viewing angles is an improvement.

To achieve a wider viewing angle, it is necessary to compensate for the viewing angle of the polarizing plate. For example, Patent No. 3526830 discloses a polarizing plate with a viewing angle compensated.

However, in the method shown in the above-mentioned Japanese Patent No. 3526830, since the optical compensation film must be two sheets, light leakage due to an increase in thickness of the display device or a crossing angle error at the time of bonding occurs, And the problem of warpage of the display device due to changes over time.

A method of controlling the wavelength dispersion of the optical compensation film to improve the viewing angle characteristics has been proposed (for example, Japanese Laid-Open Patent Publication No. 2003-202572). However, if the light described in the method controls optical parameters of wavelength dispersion known in the prior art, it is difficult to obtain good viewing angle characteristics.

The first object of the present invention is to industrially realize a comparative viewing angle of a liquid crystal display device in which the TN liquid crystal mode is further expanded, and to improve the reliability of display performance of the liquid crystal display device. That is, the comparison provides a liquid crystal display device with improved viewing angle, particularly a TN mode liquid crystal display device, and a polarizing plate that provides a contrast viewing angle for improving the liquid crystal display device.

Further, a second object of the present invention is to provide a liquid crystal display device which can accurately compensate a liquid crystal cell and has a high viewing angle contrast, in particular, a TN mode liquid crystal display device. Further, there is provided an optical compensation film which contributes to a reduction in black luminance shake in an optical wavelength region in which a liquid crystal cell, particularly a TN mode liquid crystal cell, is optically compensated to improve viewing angle contrast and black display.

The first problem described above can be solved by the following [1] to [6], and the second subject can be solved by the following [7] to [11].

[1] A liquid crystal display device comprising: a pair of substrates including at least one electrode and arranged in a pair, a liquid crystal layer provided between the substrates, and a liquid crystal disposed on a first polarizing plate outside the liquid crystal layer The display device, the thickness d (μm) of the liquid crystal layer and the product of the refractive index anisotropy Δn Δn. d is 0.2 to 1.2 μm, and the alignment state of the liquid crystal layer is changed by applying an electric field of at least two or more values, and when no application is applied to the electric field when an electric field is applied, the average alignment angle of the substrate surface of the liquid crystal layer is The first polarizing plate has a polarizing film, and a pair of protective films disposed to hold the polarizing film, and a disk-shaped compound having a position close to the liquid crystal layer on the outer side of the protective film and fixed in a misaligned state. The optically anisotropic layer, at least one of the pair of protective films is a liquid crystal display device satisfying the following formula (I), (I) 25+Re (633) ≦ Rth ≦ 250-Re (633)

[In the formula, Re(λ) is a front side hysteresis value (unit: nm) in the wavelength λ nm, Rth (λ) is a hysteresis value (unit: nm) in the film thickness direction in the wavelength λ nm, and d is the thickness of the film].

[2] The liquid crystal display device of [1], wherein at least one side of the protective film satisfies the following formula (II), (II) 5 ≦ | Re (633)|.

[3] The liquid crystal display device of [1] or [2], wherein Δnd of the liquid crystal layer and Re and Rth of at least one side of the protective film satisfy the following formula (III) and (at a wavelength of 400 to 700 nm) IV), (III) Rth ≦ nd nd / 2 (IV) Re ≦ nd nd / 2.

[4] The liquid crystal display device according to any one of [1] to [3] wherein a retardation axis of the protective film close to the liquid crystal layer is crossed with the absorption axis of the polarizing film.

[5] A polarizing plate comprising: a polarizing film; a pair of protective films disposed to hold the polarizing film; and an optically different direction of a disk-shaped compound disposed outside the protective film and fixed in a misaligned state The at least one of the pair of protective films satisfies the following formula (I), (I) 25 + Re (633) ≦ Rth ≦ 250 - Re (633)

[In the formula, Re(λ) is a front side hysteresis value (unit: nm) in the wavelength λ nm, Rth (λ) is a hysteresis value (unit: nm) in the film thickness direction in the wavelength λ nm, and d is the thickness of the film].

[6] The polarizing plate according to [5], wherein the polarizing film and the pair of protective films are formed by being wound up and wound up.

[7] An optical compensation film comprising an optical compensation film having at least a transparent film and an optically anisotropic layer having optical anisotropy in a plane, wherein the in-plane hysteresis value of the transparent film is Re, and a retardation in a thickness direction In the case of the value of Rth, the ratio of Re to Rth at a wavelength of 450 nm, Re/Rth (450 nm), is 0.39 to 0.95 times Re/Rth (550 nm) at a wavelength of 550 nm, and Re/Rth (650 nm) at a wavelength of 650 nm. It is 1.04 to 2.20 times of Re/Rth (550 nm), and Rth is 70 nm to 400 nm at a wavelength of 550 nm, and the optical anisotropic layer is formed of a composition containing a liquid crystal compound in which the optically isotropic layer is formed. The molecular system of the liquid crystal compound is fixed in an aligned state, and at least the alignment average direction in the interface of the transparent film side of the molecular symmetry axis of the liquid crystal compound is in the direction of the orthographic projection in the plane of the transparent film, and the transparent The intersection angle of the in-plane retardation axis of the film is approximately 0 degrees or approximately 90 degrees.

[8] The optical compensation film according to [7], wherein the liquid crystalline compound is a discotic liquid crystalline compound.

[9] A liquid crystal display device, comprising: a liquid crystal cell having at least one electrode and a pair of substrates arranged in opposite directions, sandwiched between the pair of substrates, containing nematic liquid crystal material, The liquid crystal molecules of the nematic liquid crystal material are driven to have a product of a slightly parallel alignment, a thickness d (micrometer) and a refractive index anisotropy Δn relative to the surface of the pair of substrates. d is a liquid crystal layer of 0.1 to 1.5 μm; holding the first and second polarizing films disposed on the liquid crystal cell; and having a transparent film between at least one side of the first and second polarizing films and the liquid crystal cell, the transparent In the case where the in-plane hysteresis value of the film is Re and the hysteresis value in the thickness direction is Rth, the ratio of Re to Rth (450 nm) at a wavelength of 450 nm is 0.39 of Re/Rth (550 nm) at a wavelength of 550 nm. 0.95 times, Re/Rth (650 nm) is 1.04 to 2.20 times of Re/Rth (550 nm) at a wavelength of 650 nm, and Rth is 70 nm to 400 nm at a wavelength of 550 nm of the transparent film, in the transparent film and the liquid crystal cell. Between the optically anisotropic layer having at least one layer formed of a composition containing a liquid crystal compound in which the molecular system of the liquid crystalline compound is fixed to an alignment state And an orientation average direction of at least the transparent film side interface of the molecular symmetry axis of the liquid crystal compound, and an intersection angle with the in-plane slow axis of the transparent film when the transparent film surface is in the direction of the orthographic projection It is roughly 0 degrees or roughly 90 degrees.

[10] The liquid crystal display device of [9], wherein the liquid crystalline compound is a discotic liquid crystalline compound.

[11] The liquid crystal display device of [9] or [10], wherein the liquid crystal cell is a liquid crystal cell of a TN mode.

Further, in the present specification, Re(λ) and Rth(λ) are hysteresis values indicating the in-plane hysteresis value and the thickness direction in the wavelength λ, respectively. Re(λ) was measured by light incident on the wavelength of λ nm in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.). Rth(λ) is the above-mentioned Re(λ), the in-plane retardation axis (which can be judged by KOBRA 21ADH), and the incident wavelength λnm from the +40° oblique direction with respect to the film normal direction as the tilt axis (rotation axis). The hysteresis value measured by light, and the hysteresis value measured by the incident light of the wavelength λnm from the direction inclined by -40° with respect to the normal direction of the film as the tilt axis (rotation axis), based on the total of 3 The set value of the hysteresis value and the average refractive index measured in each direction and the input film thickness value were calculated by KOBRA 21ADH. Here, the average refractive index can be set using the polymer handbook (JOHNWILEY & SONS, INC), and the catalogue values of various optical films. If the value of the average refractive index is not known in the past, it can be measured by an Abbe refractometer. The values of the average refractive index of the main optical film are as follows: deuterated cellulose (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polyphenylene. Ethylene (1.59).

KOBRA21ADH calculates nx, ny, and nz by inputting the set values of the average refractive indices and the film thickness. From the calculated nx, ny, and nz, Nz = (nx - nz) / (nx - ny) is further calculated.

In the present specification, the "late phase axis" means a direction in which the refractive index is the largest. In addition, the "polarizing plate" in the present specification means that both a polarizing plate including a long strip shape and a polarizing plate of a size that can be assembled to a liquid crystal device can be used unless otherwise specified. In the present specification, the "polarizing film" and the "polarizing plate" are used for the difference, and the "polarizing plate" means that the transparent protective film for protecting the polarizing film is provided on at least one surface of the "polarizing film". Laminar body.

In the present specification, "45°", "parallel" or "orthogonal" means a range of less than ±5° from a strict angle. The error with the tight angle is preferably less than 4° and preferably less than 3°. Further, the angle "+" means the clockwise direction, and the "-" means the counterclockwise direction.

Further, the "visible light region" is 380 nm to 780 nm. In addition, the measurement wavelength of the refractive index is a value of λ = 550 nm in the visible light region unless otherwise specified.

Further, the "molecular symmetry axis" in the present specification is a so-called symmetry axis in the case where the molecule has a rotational symmetry axis, and in a stricter sense, it is not necessary to require the molecule to have rotational symmetry. In general, in the discotic liquid crystal compound, the molecular symmetry axis is such that the system faces the disk surface passing through the center of the disk surface and conforms to the vertical axis, and the rod-like liquid crystal compound conforms to the long axis of the molecule.

The polarizing plate according to the first aspect of the present invention has an optically anisotropic layer containing a disk-shaped compound fixed in a misaligned state, and the protective film satisfies predetermined optical characteristics. The polarizing plate helps to expand the contrast viewing angle of the liquid crystal display device. Further, by expanding the contrast viewing angle, it is possible to improve other viewing angle characteristics such as tone inversion. Further, by imparting the function of the optical compensation film to the polarizing plate protective film, the contrast at the time of bonding can be improved, the thickness of the device can be reduced, and the warpage or unevenness of the display device can be lowered with time.

Further, the optical compensation film according to the second aspect of the present invention has a wavelength which is independent of the in-plane hysteresis value and the hysteresis value in the thickness direction by appropriately selecting a raw material or a production method, and is an optically most suitable transparent film. By using the optical compensation film, the liquid crystal cell, particularly the TN mode liquid crystal cell, can form a viewing angle compensation in a black state at substantially all wavelengths. As a result, in the liquid crystal display device having the optical compensation film, the light leakage system in the oblique direction in the black display is reduced, and the viewing angle contrast is remarkably improved. Further, in the liquid crystal display device, since light leakage in the oblique direction in the black display can be suppressed in substantially all of the visible light wavelength region, the color difference in the black display depending on the viewing angle can be improved in the conventional problem.

Embodiment of the Invention

Hereinafter, the present invention will be described in detail.

(1) A first aspect of the present invention [Liquid Crystal Display Device]

Fig. 1 is a schematic view showing an embodiment of a configuration of a transmissive liquid crystal display device according to a first aspect of the present invention.

The transmissive liquid crystal display device shown in FIG. 1 has, in order from the observation side, a transparent protective film 1, a polarizing film 3, a transparent protective film (a transparent support having an optical anisotropic layer 7) 5 and The observer-side polarizing plate composed of the optically anisotropic layer 7 is composed of a liquid crystal cell upper substrate 9, a rod-shaped liquid crystal layer 11, and a liquid crystal cell lower substrate 13, and is composed of an optically isotropic layer 14 and transparent. A protective film (a transparent support having the optically anisotropic layer 14) 16, a polarizing film 18, and a transparent protective film 20 constitute a lower polarizing plate and a backlight 22. Then, the transparent protective film, the polarizing film, the transparent support, and the optically anisotropic layer (1 to 7 and 14 to 21) constitute the polarizing plate according to the first aspect of the present invention.

It is preferable that the liquid crystal cell (9 to 13) is a liquid crystal cell of the TN mode. Further, most of the liquid crystal cell systems of the TN mode are described as being the most widely used color TFT liquid crystal display devices. The embodiment of the present embodiment will be described by using an example of a liquid crystal cell of a TN mode composed of nematic liquid crystal having positive dielectric anisotropy.

Between the upper and lower substrates 9 and 13, liquid crystals having positive dielectric anisotropy, refractive index anisotropy Δn = 0.0854 (589 nm, 20 ° C), and dielectric anisotropy Δ ε = +8.5 are sealed. The thickness d (μm) of the liquid crystal layer 11 and the product of the refractive index anisotropy Δn Δn. d is 0.2 to 1.2 μm. 0.2 to 0.5 μm is preferred. The alignment control of the liquid crystal layer 11 can be controlled by the surface properties of the alignment film (not shown) formed on the inner surfaces of the upper and lower substrates 9, 13 and the friction axes 10, 12. It is preferred that the straight line indicating the alignment direction of the liquid crystal molecules and the so-called tilt angle be about 3°. The rubbing direction is applied to the upper and lower substrates 9 and 13 in directions orthogonal to each other, and the magnitude of the tilt angle can be controlled by the strength and the number of rubbing times. The alignment film system is preferably formed by coating a polyimide film and then baking it. The magnitude of the twist angle of the liquid crystal layer 11 is determined according to the intersection angle of the rubbing directions of the upper and lower substrates 9, 13 and the palm powder added to the liquid crystal material. For example, in order to make the twist angle 90°, it is preferable to add a palm powder having a pitch of about 60 μm. The thickness d of the liquid crystal layer 11 may be, for example, about 5 μm. The liquid crystal material LC to be used is not particularly limited as long as it is a nematic liquid crystal. When the dielectric constant Δ ε is relatively large, the driving voltage can be reduced. When the refractive index anisotropy Δn is relatively small, the thickness (gap) of the liquid crystal layer can be increased, and the gap variation can be reduced. Further, when Δn is relatively large, the cell gap can be reduced, and a high-speed response can be formed. Further, the twist angle (twist angle) of the liquid crystal layer is generally viewed from the light source side toward the display side, and is observed to be clockwise rotationally twisted from the observation side, and is approximately 90° (85° to 95°). In such a range, since the white display brightness is high and the black display brightness is small, a display device having a high contrast can be obtained.

The upper polarizing plate and the lower polarizing plate each have a pair of transparent protective films 1 and 5, 16 and 20, and have optically anisotropic layers 7 and 14 containing a disk-shaped compound fixed in a misaligned state. At least one of the pair of protective films 1 and 5, 16 and 20 has optical characteristics satisfying the following formula (I) (preferably, the following formula (I'), preferably the following formula (I")). Among the protective films, at least the protective film on the light source side satisfies the following formula (I), and both of the protective films satisfy the following formula (I) (preferably, the following formula (I'), More preferably, it is preferably the following formula (I")).

(I) 25+Re (633) ≦ Rth ≦ 250-Re (633) (I') 25 + Re (633) ≦ Rth 175 + Re (633) and Rth ≦ 250-Re (633) (I") 50 + Re (633) ≦ Rth ≦150+Re(633) and Rth≦150-Re(633)

[In the formula, Re (λ) is a front side hysteresis value (unit: nm) in the wavelength λ nm, and Rth (λ) is a hysteresis value (unit: nm) in the film thickness direction in the wavelength λ nm. Also d is the thickness of the film].

When the protective film satisfies the above optical characteristics, the contrast viewing angle of the liquid crystal display device is enlarged. This can be proved in the embodiment to be described later. Theoretically, when the above formula is satisfied, the absorption axis is orthogonally observed from the oblique direction. For the polarizing plate, the observed cross angle of the polarizing plate was corrected, and it was found that it was orthogonal regardless of the angle.

Further, at least one of the pair of protective films 1 and 5, 16 and 20 (preferably at least a protective film on the liquid crystal layer side, more preferably both protective films) has an absolute value of Re of 5 nm or more at a wavelength of 633 nm. It is preferred that those of 10 nm or more are preferred. Further, at least one of the pair of protective films 1 and 5, 16 and 20 (preferably at least a protective film on the liquid crystal layer side, more preferably both protective films) has a wavelength of 400 to 700 nm, and both Re and Rth are liquid crystals. It is preferred that one half or less of the layer hysteresis value Δnd is used.

The absorption axis 4 of the upper polarizing film 3 and the absorption axis 19 of the lower polarizing film 18 are substantially orthogonally laminated, and the absorption axis 4 of the liquid crystal cell upper polarizing film 3 and the rubbing direction 10 of the upper substrate 9 are parallel. The absorption axis 19 of the lower polarizing film 18 and the rubbing direction 12 of the lower substrate 13 are laminated substantially in parallel. Further, the rubbing direction 8 of the optically anisotropic layer 7 is arranged in parallel with the absorption axis 4 of the upper polarizing film 3, and is preferably arranged in anti-parallel with the rubbing direction 10 of the upper substrate 9, and the friction of the optical anisotropic layer 14 is preferable. The direction 15 is arranged in parallel with the absorption axis 19 of the lower polarizing film 18, and is preferably arranged in anti-parallel with the rubbing direction 12 of the lower substrate 13. Further, the protective films 5 and 16 disposed near the liquid crystal cell position have the in-plane retardation axes 6 and 17, and the slow phase axes 6 and 17 are preferably arranged to intersect the absorption axes 4 and 19, respectively. A 90° cross configuration is preferred.

A transparent electrode (not shown) is formed in the inner side of the alignment film of each of the upper substrate 9 and the lower substrate 13. However, in the non-driving state in which the driving voltage is not applied to the electrodes, the liquid crystal molecules in the liquid crystal cells are slightly parallel to the substrate surface. As a result, the polarization state of the light passing through the liquid crystal panel propagates along the twist structure of the liquid crystal molecules, and the polarizing surface is rotated at 90° and emitted. That is, the liquid crystal display device realizes white display in a non-driving state. On the other hand, when the liquid crystal molecules are aligned in a direction to form a certain angle with respect to the substrate surface in the driving state, the light passing through the lower polarizing film 18 passes through the liquid crystal layer 11 while maintaining the polarization state, and is polarized by the polarizing film 3. Interrupted. In other words, a black display can be obtained in the driving state. Since the liquid crystal display device has the optical compensation layers 7 and 14 and one of the predetermined optical characteristics for the protective films 1 and 15 and 16 and 20, the tone inversion phenomenon depending on the observation direction is alleviated. And the viewing angle is improved.

Further, in the above-described embodiment, the mode of the penetration mode and the value of Δnd of the liquid crystal cell indicate the most suitable value in the penetration mode, and the liquid crystal display device according to the first aspect of the present invention may be in the reflection mode, and in the reflection mode. Since the optical path in the liquid crystal cell is twice, the optimum value of Δnd is about 1/2 of the above value. Moreover, the torsion angle is 30° to 70°, which is an optimum value.

The liquid crystal display device according to the first aspect of the present invention is not limited to the configuration shown in Fig. 1, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. The cold cathode or the hot cathode fluorescent tube, or the backlight of the light emitting diode, the field emission element, and the electroluminescent element may be configured as a light source. In the liquid crystal display device according to the first aspect of the present invention, in order to coexinate the penetration and the reflection mode, a half-transmission type in which the reflection portion and the penetration portion are provided may be included in one pixel of the display device.

The liquid crystal display device according to the first aspect of the present invention also includes a portrait direct view type, a portrait projection type, or a light modulation type. The present invention is particularly effective in an aspect suitable for an active matrix liquid crystal display device using a 3-terminal or 2-terminal semiconductor element such as a TFT or MIM. Of course, the aspect suitable for the passive matrix liquid crystal display device is also effective.

[Polarizer]

Next, a polarizing plate according to a first aspect of the present invention will be described. A polarizing plate according to a first aspect of the present invention includes: a polarizing film that holds one of the polarizing films and a protective film, and an optical film containing a discotic liquid crystal compound fixed in a misaligned state on one side of the pair of protective films An omnidirectional layer. Hereinafter, various members used in the polarizing plate according to the first aspect of the present invention will be described.

[protective film]

One of the protective polarizing films and at least one of the protective films satisfies the above formula (I). The above formula (I) is satisfied. There is no particular limitation as long as it has a material that has the properties required for the protective film. Further, among the pair of protective films, when the protective film on the side of the optically anisotropic layer is used as a support for supporting the optically anisotropic layer, it is preferable because it is thinned. It is preferable that the protective film is transparent, and specifically, a light transmittance of 80% or more is preferable. The protective film is preferably selected from the group consisting of polymer films. Examples of the polymer constituting the polymer film also include cellulose esters (for example, mono- to tri-deuterides of cellulose), norbornene-based polymers, and polymethyl methacrylate. A commercially available polymer (in the norbornene-based polymer, ARTON and ZEONEX are all trade names) can also be used. Further, it may be a polymer which is known from the prior art such as polycarbonate or polyfluorene, and which is easy to find birefringence, as described in the specification of WO00/26705, if the modification of the molecular system cannot control the discovery of birefringence. The first aspect of the present invention can also be used.

Among them, cellulose esters are preferred, and lower fatty acid esters of cellulose are preferred. The lower fatty acid means a fatty acid having 6 or less carbon atoms. In particular, deuterated cellulose having a carbon number of 2 to 4 is preferred. Cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate or cellulose acetate butyrate can also be used.

The viscosity average degree of polymerization (DP) of cellulose acetate is preferably 250 or more, and more preferably 290 or more. Further, cellulose acetate is preferably a narrow molecular weight distribution of Mw/Mn (Mw is a mass average molecular weight and Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mw/Mn is preferably 1.0 to 1.7 and preferably 1.0 to 1.65.

Further, it is preferred to use cellulose acetate having a degree of vinegar of 55.0 to 62.5%. The degree of vinegar is preferably from 57.0 to 62.0%. The degree of acetification means the amount of bound acetic acid per unit mass of cellulose. The degree of acetification can be determined by measuring and calculating the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate, etc.).

The cellulose acetate is generally such that the hydroxyl groups at the 2, 3, and 6 positions of the cellulose are not necessarily uniformly substituted, and the degree of substitution at the 6 position tends to be small. The cellulose acetate used in the above transparent support has a degree of substitution at the 6-position of cellulose which is preferably the same or more than the 2nd position and the 3rd position. The ratio of the substitution degree of the 6-position is preferably 30 to 40%, preferably 31 to 40%, and most preferably 32 to 40%, based on the total of the substitution degrees of the 2, 3, and 6 positions. The degree of substitution at the 6-position is preferably 0.88 or more.

These specific sulfhydryl groups and methods for synthesizing deuterated cellulose are described in detail on page 9 of the Inventor's Association Technical Bulletin (public technology number 2001-1745, March 15, 2001 issue of the Invention Association).

The method for adjusting the hysteresis value of the polymer film and imparting the optical characteristics satisfying the above formula (I) is generally a method of imparting an external force such as elongation. Further, if necessary, a hysteresis value increasing agent for adjusting the optical anisotropy, a compound for lowering the optical anisotropy, or a wavelength dispersion adjusting agent may be added to the polymer film. Among the hysteresis values of the deuterated cellulose film, it is preferred to use an aromatic compound having at least two aromatic rings as the hysteresis increasing agent. The aromatic compound is preferably used in an amount of 0.01 to 20 parts by mass based on 100 parts by mass of the deuterated cellulose. Further, two or more kinds of aromatic compounds may be used in combination. The aromatic ring of the aromatic compound may contain an aromatic hetero ring in addition to the aromatic hydrocarbon ring. For example, a compound described in, for example, European Patent No. 0911656A2, JP-A-2000-111914, and JP-A-2000-275434 can be mentioned.

Hereinafter, an exemplary compound which can be used as a compound for lowering the optical anisotropy of a polymer film, and an exemplified compound which can be used as a wavelength dispersion adjusting agent can be used, but it is not limited to the following compounds.

An illustration of a compound used to reduce optical anisotropy Example of wavelength dispersion adjusting agent

Further, as the hygroscopic expansion coefficient of the cellulose acetate film using a protective film, based at 30 × 10 ^{- 5} /% RH or less is preferred. Department of hygroscopic expansion coefficient of 15 × 10 ^{- 5} /% RH or less ^{preferably, 10 × 10 - 5 /%} RH or less is preferred. Also, a relatively small hygroscopic expansion coefficient is preferred, but is generally 1.0 × 10 ^- value of more than ⁵ /% RH. The coefficient of hygroscopic expansion indicates the amount of change in the length of the sample when the relative humidity is changed at a certain temperature.

By adjusting the coefficient of hygroscopic expansion, the optical properties of the optically anisotropic layer or the polarizing film are maintained as they are, and the increase in the frame-like transmittance (light leakage due to skew) can be prevented.

The method for measuring the coefficient of hygroscopic expansion is as follows. A sample having a width of 5 mm and a length of 20 mm was cut out from the produced polymer film, and one end of the single piece was fixed, and suspended at 25 ° C and 20% RH (R ⁰ ). A 0.5 g weight was suspended at the other end, left for 10 minutes and the length (L ⁰ ) was measured. Next, the temperature was still at 25 ° C and the humidity was 80% RH (R ¹ ), and the length (L ¹ ) was measured. The coefficient of hygroscopic expansion can be calculated by the following formula. In the measurement system, 10 samples were subjected to the same sample, and the average value was used.

Hygroscopic expansion coefficient [/%RH]={(L ¹ -L ⁰ )/L ⁰ }/(R ¹ -R ⁰ )

It is preferable to add a compound having a hydrophobic group or fine particles, etc., because the dimensional change due to moisture absorption of the polymer film is small. The compound having a hydrophobic group is preferably selected from a plasticizer or a deterioration inhibitor of a hydrophobic group having an aliphatic group or an aromatic group in the molecule. The amount of these compounds added is preferably in the range of 0.01 to 10% by mass based on the adjusted solution (slurry). Moreover, it is preferable to reduce the free volume in the polymer film. Specifically, the amount of residual solvent at the time of film formation by the solution casting method described later is small, and the free deposition becomes small. It is preferred to carry out drying in a range of 0.01 to 1.00% by mass based on the residual solvent amount of the cellulose acetate film.

The above additive added to the polymer film or an additive added for various purposes (for example, an ultraviolet inhibitor, a release agent, an antistatic agent, a deterioration inhibitor (for example, an antioxidant, a peroxide decomposer, a radical inhibitor, A metal inerting agent, an acid scavenger, an amine, an infrared absorber, etc. may be a solid or an oil. Further, in the case where the film is formed of a plurality of layers, the type or amount of addition of each layer may be different. These details are preferably those described in detail in pages 16 to 22 of the above-mentioned technique No. 2001-1745. The amount of each raw material added is not particularly limited as long as the function can be found, but it is preferably 0.001 to 25% by mass in the total composition of the polymer film.

[Method of preparing polymer film]

The polymer film is preferably produced by a solution casting method. The solution casting method uses a solution (glue) in which a polymer material is dissolved in an organic solvent and a film is produced. The above solution casting method is to cast a paste onto a drum or a conveyor belt to evaporate the solvent and form a film. It is preferable that the pre-casting glue is adjusted to have a solid content of 18 to 35%. The surface of the drum or conveyor belt is preferably in the form of a mirror finish.

The glue is preferably cast on a drum or a conveyor belt having a surface temperature of 10 ° C or less. The casting system is preferably blown and dried in a wind of 2 seconds or more. The obtained film is peeled off from a drum or a conveyor belt, and then dried under a high-temperature air which is continuously changed from 100 to 160 ° C to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, the time from casting to stripping can be shortened. Because of this method, the glue must be gelled at the surface temperature of the running drum or conveyor belt.

In the casting step, one type of the deuterated cellulose solution may be cast in a single layer, or two or more types of the deuterated cellulose solution may be simultaneously or successively cast.

A method of co-casting a plurality of layers of a deuterated cellulose solution as described above, for example, casting a solution containing deuterated cellulose in a plurality of casting openings at intervals in which the support is carried out And a method of laminating a method of casting a deuterated cellulose solution from two casting openings (method described in JP-A-6-134933); The viscosity-degraded cellulose solution is contained in a low-viscosity deuterated cellulose solution, and the high- and low-viscosity deuterated cellulose solution is simultaneously extruded (method described in JP-A-56-162617). The first aspect of the present invention is not limited thereto.

The manufacturing steps of these solution casting methods are described in detail on pages 22 to 30 of the above-mentioned public technical number 2001-1745, and are classified into dissolution, casting (including co-casting), metal support, drying, and Peeling, stretching, etc.

The thickness of the film used as the protective film is preferably 15 to 120 μm, and preferably 30 to 80 μm.

[Surface treatment of polymer film]

It is preferred to apply a surface treatment to the polymer film. The surface treatment system includes a charge discharge treatment, a glow discharge treatment, a flame treatment, an acid treatment, an alkali treatment, and an ultraviolet irradiation treatment. They are described in detail on pages 30 to 32 of the above-mentioned public technical number 2001-1745. Among these, the surface treatment of the saponified cellulose film which is particularly preferably alkali saponified is very effective.

The alkali saponification treatment may be carried out by immersing in a saponification liquid, coating a saponification liquid, or the like, but a coating method is preferred. The coating method may, for example, be a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, or an E-type coating method. The alkali saponification treatment liquid is, for example, a potassium hydroxide solution or a sodium hydroxide solution, and the predetermined concentration of the hydroxide ions is preferably in the range of 0.1 to 3.0 N. Further, by containing a solvent having good wettability to the film (for example, isopropyl alcohol, n-butanol, methanol, ethanol, etc.), a surfactant, a wetting agent (for example, glycols, glycerin, etc.) As the alkali treatment liquid, the saponification liquid is excellent in the wettability of the transparent support and the stability with time of the saponification liquid. Specifically, the contents of the contents of JP-A-2002-82226 and WO02/46809 are described.

In place of the surface treatment, for example, an undercoat layer to which only one layer is applied is applied to the polymer film (described in JP-A-H07-333433), or gelatin containing both a hydrophobic group and a hydrophilic group. The single layer method of the resin layer is a more dense layer of the first layer (hereinafter, abbreviated as the first layer of the undercoat layer), and a hydrophilic layer of gelatin or the like which is a second layer and is more closely adhered to the alignment film is applied thereon. The content of the resin layer (hereinafter, abbreviated as the second layer of the primer layer) is described in the above-mentioned "multilayer method" (for example, JP-A-H11-248940).

[optical anisotropic layer]

The optically anisotropic layer contains a discotic compound fixed in a mixed alignment state. Hereinafter, preferred aspects of the optically anisotropic layer will be described in detail.

The optically anisotropic layer is preferably designed to compensate for liquid crystal compounds in the liquid crystal cells of the black display of the liquid crystal display device. The alignment state of the liquid crystal compound in the liquid crystal cell in the black display differs depending on the mode of the liquid crystal display device. The alignment relationship between the alignment state of the liquid crystal compound in the liquid crystal cell and the compensation film is described in IDW'00, FMC7-2, and P411 to 414.

In the optically anisotropic layer, since the discotic compound is a miscellaneous alignment, the optically anisotropic layer is averaged with respect to the average of the inclination angle of the layer plane of the long axis of the discotic compound (longitudinal diameter of the disc surface). The depth direction and the increase in the distance from the transparent support interface are simultaneously increased or decreased. The average of the tilt angles is preferably increased as the distance increases. Further, the change in the inclination angle includes a continuous increase, a continuous decrease, an intermittent increase, a intermittent decrease, a continuous increase and a continuous decrease, or may be a change including intermittent increase and decrease. The intermittent change is a region in which the inclination angle does not change in the middle of the thickness direction. In the first aspect of the present invention, even if a region where the inclination angle does not change is included, the whole can be increased or decreased. Further, it is preferable that the inclination angle is continuously changed.

The optically anisotropic layer is formed by applying a composition containing a liquid crystalline discotic compound to the surface of a transparent support, and if necessary, heating or the like. The liquid crystal disk-shaped compound is preferably used for forming the above-mentioned desired alignment state, and an alignment film or a material for controlling liquid crystal molecules such as a palm, a surfactant, or a polymer. For example, when an alignment film is used, the long axis alignment direction of the liquid crystalline disk-shaped compound in the alignment film interface can be adjusted to a desired direction by selecting a material of the alignment film or by selecting a rubbing treatment method. Further, the direction of the major axis (disk surface) of the disk-shaped compound on the surface side (air side) can be generally adjusted by selecting the type of the disk-shaped compound or the additive used together with the disk-shaped compound. Further, the composition for forming an optically anisotropic layer may contain a polymerizable monomer, an initiator, and the like which are used for fixing a liquid crystalline disk-shaped compound.

[disc compound]

An example of a disc-shaped (disc) compound which can be used in the first aspect of the present invention includes a research report by C. Destrade et al., Mol. Cryst., Vol. 71, p. 111 (1981). Reported by Benzene Derivatives, C. Destrade, et al., Mol. Cryst. Vol. 122, p. 141 (1985), Physics lett, A, Vol. 78, p. 82 (1990) Research report of triacylene derivatives, B. Kohne et al., research report of cyclohexane derivatives and JMLehn humans described in Angew. Chem., vol. 96, p. 70 (1984), J .Chem.Commun., p. 1794 (1985), J. Zhang et al., J. Am. Chem. Soc. Vol. 116, p. 2655 (1994). Phenylacetylene macrocycle.

In the example of the discotic compound, a liquid crystal having a linear alkyl group, an alkoxy group, a substituted benzoquinoneoxy group as a mother nucleus, and a structure showing a radiation substitution structure may be contained with respect to the core nucleus at the center of the molecule. Sex compounds. A collection system of molecules or molecules has a rotational symmetry and is preferably a compound which imparts a certain alignment. A preferred example of the discotic compound is described in JP-A-8-50206.

[Additives for optically oriented layers]

The composition for forming an optically anisotropic layer may contain various additives mainly for the palm powder in addition to the above-mentioned discotic compound. Examples of the additive include a plasticizer, a surfactant, a polymerizable monomer, and the like. These additives are imparted by improving the uniformity of the coating film, the strength of the film, or the alignment of the discotic compound. The surfactant is, for example, the following fluorine-containing surfactant.

Fluorinated surfactant

The polymerizable single system is, for example, a radically polymerizable or cationically polymerizable compound. Preferably, a polyfunctional radical polymerizable monomer, a liquid crystal compound containing the above polymerizable group, and a copolymerization property are preferred. For example, the paragraph numbers [0018] to [0020] in the specification of JP-A-2002-296423. The amount of the compound to be added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass based on the discotic compound.

The surfactant may, for example, be a conventionally known compound, and particularly preferably a fluorine-based compound. Specifically, for example, the compounds described in paragraphs [0028] to [0056] in the specification of JP-A-2001-330725 can be mentioned.

The polymer used together with the discotic compound is preferably one which imparts a tilt angle to the discotic compound.

An example of the polymer is, for example, a cellulose ester. A preferred example of the cellulose ester is described in paragraph number [0178] in the specification of JP-A-2000-155216. In order to prevent the alignment of the liquid crystalline disc-like compound, the amount of the polymer added is preferably in the range of 0.1 to 10% by mass, preferably 0.1 to 8% by mass, based on the liquid crystalline discotic compound.

[Formation of optical anisotropic layer]

The optically anisotropic layer can be formed by applying a coating liquid containing a liquid crystalline disk-shaped compound and, if necessary, an additive to the surface of the alignment film.

The solvent to be used in the coating liquid is preferably an organic solvent. Examples of the organic solvent include a mercaptoamine group (for example, N,N-dimethylformamide), an anthracene (for example, dimethylhydrazine), a heterocyclic compound (for example, pyridine), a hydrocarbon (for example, benzene, Hexane), alkyl halides (eg, chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (for example, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more types of organic solvents may be used in combination.

The application of the coating liquid can be carried out by a well-known method (for example, a wire bar coating method, an extrusion coating method, a co-gravure coating method, a reverse gravure coating method, a die coating method).

[Fixation of discotic compound]

The liquid crystalline discotic compound can be fixed while maintaining the alignment state. The immobilization is preferably carried out by a polymerization reaction. The polymerization reaction involves thermal polymerization using a thermal polymerization initiator, and photopolymerization using a photopolymerization initiator. Photopolymerization is preferred.

Examples of the photopolymerization initiator include an α-carbonyl compound (described in each specification of U.S. Patent No. 2,376,661, the same as No. 2,367,670), an acetoin (described in the specification of U.S. Patent No. 24,488,828), and an α-hydrocarbon-substituted aromatic auxin. Compounds (described in U.S. Patent No. 2,722,512), polynuclear ruthenium compounds (described in U.S. Patent No. 3,046,127, issued to each specification), and the combination of triaryl imidazole dimer and p-aminophenyl ketone (U.S. Patent No. 3,549,367) Record), acridine and pheno The compound (described in the specification of JP-A-60-105667, US Pat. No. 4,239,850) and the oxadiazole compound (described in the specification of U.S. Patent No. 4,212,970).

The amount of the photopolymerization initiator to be used is preferably in the range of 0.01 to 20% by mass of the solid content of the coating liquid, and preferably in the range of 0.5 to 5% by mass.

The light irradiation system for polymerizing the liquid crystalline discotic compound is preferably ultraviolet light. The irradiation energy is preferably in the range of 20 mJ/cm ² to 50 J/cm ² , more preferably in the range of 20 to 5,000 mJ/cm ² , and still more preferably in the range of 100 to 800 mJ/cm ² . Further, in order to promote the photopolymerization reaction, light irradiation may be performed under heating conditions.

The protective layer may also be disposed on the optically anisotropic layer.

[Alignment film]

The alignment film system has a function of specifying the direction in which the discotic compound is aligned. The liquid crystal disc-shaped compound is preferably an alignment film in order to form the alignment state. However, if the alignment state is fixed after the liquid crystal disc-like compound is aligned, since the alignment film is finally in proportion, it has already been used. There is no need as a constituent element. That is, only the optically anisotropic layer on the alignment film fixed in the alignment state may be transferred onto the transparent support.

The alignment film may be subjected to rubbing treatment with an organic compound (preferably a polymer), oblique vapor deposition of an inorganic compound, formation of a layer having microgrooves, or accumulation of an organic compound by a Langmuir-Biodgett method (LB film) (for example) It is provided by means such as ω-trisuccinic acid, octadecylmethylammonium chloride or methyl stearate. Further, an alignment film that imparts an electric field, imparts a magnetic field, or is irradiated with light to generate an alignment function is also known.

The alignment film is preferably formed by a rubbing treatment of a polymer. The polymer used in the alignment film is based on a certain molecular structure having a function of aligning liquid crystal molecules. In the first aspect of the present invention, in addition to the function of aligning liquid crystal molecules, a side chain having a crosslinkable functional group (for example, a double bond) is bonded to a main chain, or a function of aligning a liquid crystal molecule to a function can be achieved. It is preferred that the linking functional group be introduced into the side chain.

The polymer used in the alignment film may be any of its self-crosslinkable polymer or a polymer crosslinkable by a crosslinking agent, and may be used in plural.

Examples of the polymer include a methacrylate copolymer, a styrene copolymer, a polyolefin, a polyvinyl alcohol, and a modified polyvinyl alcohol described in Paragraph No. [0022] in the specification of JP-A-8-338913. , poly(N-methylol acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate, and the like. A decane coupling agent can be used as the polymer. Water-soluble polymer (for example, poly(N-methylol acrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) is preferred, gelatin, polyvinyl alcohol and modified polyethylene Alcohol is preferred, polyvinyl alcohol and modified polyvinyl alcohol are preferred. It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization.

The degree of saponification of polyvinyl alcohol is preferably from 70 to 100%, preferably from 80 to 100%. The degree of polymerization of polyvinyl alcohol is preferably from 100 to 5,000.

A side chain having a function of aligning liquid crystal molecules, and generally has a hydrophobic group as a functional group. The specific functional group type is determined depending on the type of liquid crystal molecule and the necessary alignment state.

For example, the modified base of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain shift modification, or block polymerization modification. Examples of the modifying group include a hydrophilic group (a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, an amine group, an ammonium group, a decyl group, a fluorenyl group, etc.), a hydrocarbon group having 10 to 100 carbon atoms, and fluorine. Atom-substituted hydrocarbon group, thioether group, polymerizable group (unsaturated polymerizable group, epoxy group, ethylenediimide group, etc.), alkoxyalkyl group (trialkoxy group, dialkoxy group, monoalkane) Oxy) and the like. Specific examples of such modified polyvinyl alcohol compounds are, for example, paragraph numbers [0022] to [0145] in the specification of JP-A-2000-155216, and paragraph numbers [0018] in the specification of JP-A-2002-62426. The person recorded in 0022].

The polymer of the alignment film can be obtained by binding a side chain having a crosslinkable functional group to the main chain of the alignment film polymer or by introducing a crosslinkable functional group on a side chain having a function of the alignment liquid crystal molecule Copolymerization with a polyfunctional monomer contained in the optically anisotropic layer. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer, and between the polyfunctional monomer and the alignment film polymer, a covalent bond is Strongly bonded. Therefore, the strength of the optical compensation film can be remarkably improved by introducing a crosslinkable functional group into the alignment film polymer.

The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specifically, for example, the paragraph number [0080] to [0100] in the specification of Japanese Laid-Open Patent Publication No. 2000-155216, and the like.

The alignment film polymer may be crosslinked by using a crosslinking agent in addition to the above crosslinkable functional group.

The crosslinking agent is an aldehyde, an N-methylol compound, a dioxane derivative, a compound which acts via an activated carboxyl group, a reactive vinyl compound, an active halogen compound, an isoxazole, and a dialdehyde starch. It is also possible to use two or more kinds of crosslinking agents in combination. Specifically, for example, the compounds described in paragraphs [0023] to [024] in the specification of JP-A-2002-62426. It is preferred to use a highly reactive aldehyde, particularly glutaraldehyde.

The amount of the crosslinking agent to be added is preferably 0.1 to 20% by mass, and preferably 0.5 to 15% by mass based on the total amount of the polymer. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, preferably 0.5% by mass or less. By this adjustment or the like, even if the alignment film is used for a long period of time in a liquid crystal display device or in a high-temperature and high-humidity environment, it is possible to obtain a mesh without sufficient durability.

The alignment film system can be formed by applying the above-mentioned polymer or crosslinking agent containing an alignment film forming material to a transparent support, followed by heat drying (crosslinking) and rubbing treatment. The crosslinking reaction can be carried out at any time after application to a transparent support as described above. In the case of using a water-soluble polymer such as polyvinyl alcohol as the material for forming an alignment film, the coating liquid is preferably a mixed solvent of an organic solvent having a defoaming action (for example, methanol) and water. The ratio is preferably in the mass ratio, water: methanol is preferably 0:100 to 99:1, and 0:100 to 91:9 is preferred. Thereby, the occurrence of bubbles is suppressed, and defects of the alignment film and the surface of the layer of the optically anisotropic layer are remarkably reduced.

The coating method of the alignment film is preferably a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, or a roll coating method. In particular, the bar coating method is preferred. Further, the film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be carried out at 20 ° C ~ 110 ° C. In order to form sufficient crosslinking, it is preferably 60 ° C to 100 ° C, particularly preferably 80 ° C to 100 ° C. The drying time can be carried out for 1 minute to 36 hours, preferably 1 minute to 30 minutes. Further, the pH is preferably set to a value suitable for the crosslinking agent to be used, and in the case of using glutaraldehyde, the pH is preferably 4.5 to 5.5, particularly preferably 5.

The alignment film may be formed on the surface of the undercoat layer in the case where the undercoat layer is provided on the surface of the transparent support or based on the desired transparent support. The alignment film can be produced by rubbing the surface after crosslinking the polymer layer as described above.

The above rubbing treatment can be applied as a processing method widely used as a liquid crystal alignment processing step of an LCD. That is, the surface of the alignment film can be obtained by using paper or a sterilizing cloth, felt, rubber or nylon, polyester fiber or the like and wiping in a certain direction to obtain an alignment. In general, it can be carried out by using a cloth of a fiber having an average planting length and a uniform thickness, and rubbing it for several times.

Next, the alignment film function is exerted to align the liquid crystalline discotic compound of the optically anisotropic layer provided on the alignment film. Subsequently, the alignment film polymer may be reacted with the polyfunctional monomer contained in the optically anisotropic layer as needed, or a crosslinking agent may be used to crosslink the alignment film polymer.

The film thickness of the alignment film is preferably in the range of 0.1 to 10 μm.

Further, the optically anisotropic layer may be formed directly on the surface of the polarizing film. Specifically, the optically anisotropic layer can be formed by applying the coating liquid for an optically anisotropic layer as described above to the surface of the polarizing film. As a result, a polymer film is not used between the polarizing film and the optically anisotropic layer, and a thin polarizing plate having a small stress (warpage × cross-sectional area × elastic modulus) as the size of the polarizing film changes is produced. When the polarizing plate according to the first aspect of the present invention is assembled to a large-sized liquid crystal display device, there is no problem such as light leakage, and an image with a high display quality is displayed.

[Polarizing film]

The polarizing film which can be used in the first aspect of the present invention is a coating type polarizing film typified by Optiva Inc., or a polarizing film composed of a binder and iodine or a dichroic dye. The iodine and the dichroic dye in the polarizing film are deflected by alignment in the binder. The iodine and the dichroic dye are aligned along the binder molecules, or are aligned in a single direction by organizing the dichroic dye such as a liquid crystal. Commercially available polarizers are generally produced by immersing the stretched polymer in a solution of iodine or a dichroic dye in a bath to saturate iodine or a dichroic dye in the binder. It can be made in a binder.

The commercially available polarizing film is mainly composed of iodine or a dichroic dye which is about 4 μm from the surface of the polymer (about 8 μm on both sides), and in order to obtain sufficient polarizing performance, a polarizing film having a thickness of 10 μm or more is preferably used. The degree of impregnation can be controlled according to the solution concentration of iodine or a dichroic dye, the temperature of the bath, and the immersion time.

As described above, the lower limit of the thickness of the binder is preferably 10 μm. The upper limit of the thickness is from the viewpoint of light leakage of the liquid crystal display device, and the thinner the better. Commercially available polarizing plates (about 30 μm) or less are preferred, and 25 μm or less is preferable, and 20 μm or less is preferable. When the thickness is 20 μm or less, the light leakage phenomenon is not observed in a 17-inch liquid crystal display device.

The binder of the polarizing film can be crosslinked. The crosslinked binder can be used as a self-crosslinkable polymer. A polarizing film can be produced by reacting a polymer having a functional group or introducing a functional group into a polymer by changing light, heat or pH to cause a reaction between the binders. Further, a crosslinked structure can be introduced into the polymer by a crosslinking agent. Cross-linking is generally carried out by applying a coating liquid containing a polymer or a mixture of a polymer and a crosslinking agent onto a transparent support, followed by heating. At the stage of the final product, it is ensured that the formation durability is excellent, so the crosslinking treatment can also be carried out in any stage in obtaining the final polarizing plate.

The binder of the polarizing film may also be any of its self-crosslinkable polymer or a polymer crosslinked via a crosslinking agent. Examples of the polymer are, for example, the same as those described for the alignment film described above. Polyvinyl alcohol and modified polyvinyl alcohol are preferred. The modified polyvinyl alcohol is described in each of the publications of JP-A No. 8-338913, No. 9-152509, and No. 9-316127. Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

The amount of the crosslinking agent added to the binder is preferably from 0.1 to 20% by mass based on the binder. The alignment of the polarizing element and the moist heat resistance of the polarizing film are good.

The alignment film contains a certain amount of unreacted crosslinking agent even after the end of the crosslinking reaction. However, the amount of the residual crosslinking agent is preferably 1.0% by mass or less and preferably 0.5% by mass or less in the alignment film. In this case, the polarizing film is assembled to the liquid crystal display device, used for a long period of time, or placed in a high-temperature and high-humidity environment for a long period of time, and the degree of polarization is not lowered.

Crosslinking agents are described in the specification of U.S. Reissue Patent No. 23,297. Further, a boron compound (for example, boric acid or borax) can also be used as a crosslinking agent.

The dichroic dye is an azo dye, an anthraquinone dye, a pyrazolium dye, a triphenylmethane dye, a quinoline dye, or an evil. Pigment, thiophene A pigment or an anthraquinone pigment. The dichroic dye is preferably water soluble. The dichroic dye system preferably has a hydrophilic substituent (for example, a sulfo group, an amine group, or a hydroxyl group). Examples of the dichroic dyes are, for example, the compounds described in the Inventive Association Public Technology, Public Technology No. 2001-1745, and page 58 (issued on March 15, 2001).

The polarizing film is preferably dyed from the viewpoint of the yield in the longitudinal direction (MD direction) of the polarizing film (extension method) or after rubbing (friction method), and is dyed with iodine or a dichroic dye.

In the case of the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, preferably 3.0 to 10.0 times. The extension can be implemented with a dry extension in the air. Further, it is also possible to perform wet stretching in a state of being immersed in water. The stretching ratio of the dry stretching is preferably 2.5 to 5.0 times, and the stretching ratio of the wet stretching is preferably 3.0 to 10.0 times. The step of extending can also be carried out by dividing the number including the oblique extension. By dividing into several times, although extending at a high magnification, it can be further uniformly extended. A number of extensions (to the extent of preventing wide-direction contraction) can also be made in the lateral or longitudinal direction before extension. The extension can be carried out by a different stretching step in a tenter extending in two directions. The above biaxial stretching system is the same as the stretching method performed in general film forming. In the biaxial stretching, since the stretching is performed by different speeds at right and left, the thickness of the adhesive film before stretching must be different from left to right. In the cast film formation, the difference between the left and right can be pulled up in the flow rate of the binder solution by attaching a cone to the die.

The rubbing method can be applied as a rubbing treatment method widely used in the LCD liquid crystal alignment processing step. That is, the surface of the film is wiped in a certain direction by using paper or sterilizing cloth, felt, rubber or nylon or polyester fiber to obtain alignment. In general, it can be carried out by using a cloth having an average planting length and a uniform thickness and rubbing a plurality of times. It is preferable to use a friction roller having a roundness, a cylindricality, and a deflection (eccentricity) of the roller itself of 30 μm or less. The polishing angle of the film of the rubbing roller is preferably 0.1 to 90°. However, as described in Japanese Laid-Open Patent Publication No. Hei 8-160430, a stable rubbing treatment can be performed by crimping to 360° or more. In the case of rubbing a long strip film, it is preferable that the film is conveyed at a speed of 1 to 100 m/min under a certain tension by a transfer device. The friction roller is preferably freely rotatable in a horizontal direction with respect to the film direction by setting an arbitrary friction angle. It is preferable to select an appropriate rubbing angle in the range of 0 to 60°.

It is preferable that the polarizing plate according to the first aspect of the present invention can be wound up and wound out. In the method of the roll-in/roll-out method, for example, a long protective film wound in a roll shape and a long polarizing film wound in a roll shape are continuously laminated and further curled into a roll shape. Because it can be manufactured continuously, it contributes to the improvement of productivity.

On one surface of the polarizing film, a laminated body in which the optically anisotropic layer is formed on a transparent support (also a protective film) may be bonded (hereinafter, the laminated body may also be referred to as an "optical compensation film"). ). The surface to which the polarizing film is bonded is preferably the inside of the transparent support (the side on which the optically isotropic layer is not formed). When bonding, an adhesive can be used. As the subsequent agent, a polyvinyl alcohol-based resin (including a modified polyvinyl alcohol based on an ethyl sulfonium group, a sulfonic acid group, a carboxyl group, or an alkyloxy group) or an aqueous solution of a boron compound can be used. A polyvinyl alcohol-based resin is preferred. The adhesive is applied to the bonding surface of the polarizing film and/or the optical compensation film to form an adhesive layer, and both of them are laminated, and they can be bonded by heating or pressurization as desired. The thickness of the above-mentioned adhesive layer is preferably in the range of 0.01 to 10 μm after drying, and particularly preferably in the range of 0.05 to 5 μm.

Both the optical compensation film and the polarizing film can be wound into the unwinding pattern for lamination.

On the other surface of the polarizing film, a polymer film or the like of a protective film is bonded. The material of the polymer film is not particularly limited as long as it has functional properties as a protective film for a polarizing film. Further, the polymer film may be designed as an antireflection film having antifouling properties and scratch resistance on the outermost surface. The antireflection film system can also be used in any of the conventionally known ones.

In order to improve the contrast of the liquid crystal display device, the transmittance of the polarizing plate is preferably higher, and the polarizing degree is also higher. The transmittance of the polarizing plate is in the light having a wavelength of 550 nm, preferably in the range of 30 to 50%, preferably in the range of 35 to 50%, and preferably in the range of 40 to 50%. The degree of polarization is preferably in the range of 90 to 100% in the light having a wavelength of 550 nm, preferably in the range of 95 to 100%, and preferably in the range of 99 to 100%.

(2) The second aspect of the present invention

Hereinafter, the action of the second aspect of the present invention will be described using the drawings.

Fig. 3 is a schematic view showing a configuration example of the liquid crystal display device of the second aspect of the present invention. The liquid crystal display device of the TN mode shown in FIG. 3 has a liquid crystal cell composed of a liquid crystal layer 57 whose liquid crystal is curved and aligned with the substrate surface and a substrate 56 and 58 which are held by the liquid crystal when the voltage is applied, that is, when the black display is performed. . The substrates 56 and 58 are applied to the alignment of the liquid crystal surface, and the rubbing direction is indicated by an arrow RD. The situation inside is indicated by a dotted arrow. The liquid crystal cell is held and the polarizing films 51 and 61 are disposed. The transmission axes 52 and 62 of the polarizing films 51 and 61 are orthogonal to each other, and are disposed at an angle of 0 or 90 degrees with respect to the RD direction of the liquid crystal layer 57 of the liquid crystal cell. The transparent films 53 and 63 and the optically anisotropic layers 55 and 59 are disposed between the polarizing films 51 and 61 and the liquid crystal cell. The transparent films 53 and 63 are formed by the retardation axes 53a and 63a in parallel with the directions of the transmission axes 52 and 62 of the polarizing films 51 and 61 adjacent thereto. Further, the optically anisotropic layers 55 and 59 have an optical anisotropy which is found by aligning a liquid crystal compound.

The liquid crystal cell layer in Fig. 3 has a liquid crystal layer formed of the upper substrate 56 and the lower substrate 58 and the liquid crystal molecules 57 held thereby. In the surface of the liquid crystal molecules 57 contacting the substrates 56 and 58 (hereinafter referred to as "inner surface"), an alignment film (not shown) is formed, and the liquid crystal molecules are applied in a voltage-free state or in a low applied state. The alignment of 57 is controlled to have a parallel direction of pretilt angle. Further, on the inner faces of the substrates 56 and 58, a transparent electrode (not shown) to which a voltage can be applied is formed in the liquid crystal layer composed of the liquid crystal molecules 57. In a second aspect of the invention, the thickness d (micrometer) of the liquid crystal layer and the product of the refractive index anisotropy Δn Δn. The d is preferably 0.1 to 1.5 μm, and further preferably 0.2 to 1.5 μm, more preferably 0.2 to 1.2 μm, and further preferably 0.6 to 0.9 μm. In such a range, by increasing the white display brightness when the white voltage is applied, a display device having a significantly high contrast can be obtained. The liquid crystal material to be used is not particularly limited. In the aspect in which an electric field is applied between the upper and lower substrates 56 and 58, a liquid crystal material having a positive dielectric anisotropy is used to respond to the liquid crystal molecules 57 parallel to the electric field direction. .

For example, in the case where the liquid crystal cell is a TN mode liquid crystal cell, a nematic liquid crystal material having positive dielectric anisotropy and Δn=0.08, Δε=5 or the like can be used between the upper and lower substrates 56 and 58. The thickness d of the liquid crystal layer is not particularly limited, and in the case of using a liquid crystal having the above-described characteristics, it can be set to about 6 μm. According to the thickness d, the product of the refractive index anisotropy Δn when applied with a white voltage Δn. The size of d, the brightness of the white display is changed, so in order to obtain sufficient brightness when the white voltage is applied, the liquid crystal layer will be Δn in the non-applied state. The d is preferably in the range of 0.6 to 1.5 μm.

Further, in the liquid crystal display device of the TN mode, it is also possible to add a pair of materials for reducing misalignment. Also, a multi-region structure is used in the TN mode. The multi-domain structure is a structure in which one pixel of a liquid crystal display device is divided into a plurality of regions. For example, when a multi-region structure is formed in the TN mode, it is preferable that the viewing angle characteristics of luminance or hue are improved. Specifically, each pixel is configured and averaged in a region in which the initial alignment state of the liquid crystal molecules is 2 or more (preferably 4 or 8) different from each other, and variations in luminance or color tone depending on the viewing angle can be reduced. Further, in the voltage application state, each pixel is configured from a region different from each other in which the alignment direction of the liquid crystal molecules is continuously changed, and the same effect can be obtained.

The transparent films 53 and 63 are at a wavelength of 450 nm, and the ratio of Re to Rth, Re/Rth (450 nm), is 0.39 to 0.95 times Re/Rth (550 nm) at a wavelength of 550 nm, and Re/Rth (650 nm) at a wavelength of 650 nm. It satisfies the relationship of 1.04 to 2.20 times of Re/Rth (550 nm), and Rth is 70 to 400 nm. The transparent films 53 and 63 may have a function as a support of the optically anisotropic layers 55 and 59, or may have a function as a protective film of the polarizing film 51 and the polarizing film 61, or may have both functions. In other words, the polarizing film 51, the transparent film 53, the optically anisotropic layer 55, or the polarizing film 61, the transparent film 63, and the optically anisotropic layer 59 can be incorporated into the liquid crystal display device as an integrated laminated body, or Each is assembled as a separate component. Further, between the transparent film 53 and the polarizing film 51, or between the transparent film 63 and the polarizing film 61, a protective film for a polarizing film for other purposes may be disposed, but it is preferable that the protective film is not disposed. The retardation axis 53a of the transparent film 53 and the slow axis 63a of the transparent film 63 are preferably substantially parallel or orthogonal to each other. When the retardation axes 53a and 63a of the transparent films 53 and 63 are orthogonal to each other, the birefringence of each transparent film is canceled, and the optical characteristics of the light perpendicular to the liquid crystal display device can be reduced. Further, the retardation axes 53a and 63a are parallel to each other, and the phase difference can be compensated by the birefringence of the protective film in the case where the liquid crystal layer has a residual phase difference.

The transmission axes 52a and 62 of the polarizing films 51 and 61, the slow axis directions 53a and 63a of the transparent films 53 and 63, and the alignment direction of the liquid crystal molecules 57 are based on the materials, display modes, and members used in the respective members. The laminated structure and the like are adjusted to the most suitable range. That is, the transmission axis 52 of the polarizing film 51 and the transmission axis 62 of the polarizing film 61 are arranged to be substantially orthogonal to each other. However, the liquid crystal display device according to the second aspect of the present invention is not limited to this configuration.

The optically oriented layers 55 and 59 are disposed between the transparent films 53 and 63 and the liquid crystal cell. The optically anisotropic layers 55 and 59 are layers formed of a liquid crystal compound, for example, a composition containing a rod-like compound or a disk-shaped compound. In the optically anisotropic layer, the molecular system of the liquid crystal compound is fixed in a predetermined alignment state. In the optically isotropic layers 55 and 59, the molecular symmetry axes of the liquid crystal compounds, at least the alignment average directions 55a and 59a in the interface between the transparent films 53 and 63, and the in-plane slow axis 53a of the transparent films 53 and 63 and 63a, which is roughly 0 degrees or roughly 90 degrees (the figure in Figure 3 shows a cross at 90 degrees). When arranged in this relationship, the optically anisotropic layer 55 or 59 generates a hysteresis value for incident light from the normal direction without generating light leakage, and the present invention can be sufficiently represented for incident light from an oblique direction. The effect of the second aspect. Even at the interface of the liquid crystal cell side The orientation average direction of the molecular symmetry axes of the optically anisotropic layers 55 and 59 is preferably such that the in-plane slow axises 53a and 63a of the transparent films 53 and 63 are substantially 0 degrees or substantially 90 degrees. Further, in the alignment average direction 55a of the polarizing film side (transparent film interface side) of the molecular symmetry axis of the liquid crystal compound of the optically anisotropic layer 55, the transmission axis 52 of the polarizing film 51 which is closer to the position is arranged to be substantially 0. Degrees or roughly 90 degrees are better (in Figure 3, the configuration shows 0 degrees). Similarly, the alignment average direction 59a of the polarizing film side (transparent film interface side) of the molecular symmetry axis of the liquid crystal compound of the optically anisotropic layer 59 is arranged to be substantially larger than the transmission axis 62 of the polarizing film 61 which is closer to the position. 0 degrees or slightly 90 degrees is better (the figure shown in Figure 3 shows 0 degrees). When configured in this relationship, the light can be switched according to the sum of the hysteresis value generated by the optical anisotropic layer 55 or 59 and the hysteresis value generated in the liquid crystal layer, and the incident light from the oblique direction can be sufficiently expressed. The effect of the second aspect of the invention.

Next, the principle of the image display of the liquid crystal display device of Fig. 3 will be described.

In a driving state in which a driving voltage corresponding to black is applied to each of the transparent electrodes (not shown) of the liquid crystal cell substrates 56 and 58, the liquid crystal molecules 57 in the liquid crystal layer are changed from the twisted alignment in the initial state to form liquid crystal molecules to be close to standing. In the state, the polarization state of the incident light in the front direction hardly changes. Since the transmission axes 52 and 62 of the polarizing films 51 and 61 are orthogonal to each other, light incident from the lower side (for example, the back surface electrode) is polarized by the polarizing film 61, and continues to maintain the polarized state through the liquid crystal cells 55 to 58. And is blocked by the polarizing film 51. That is, in the liquid crystal display device of Fig. 3, black display in the driving state is realized. On the other hand, a transparent electrode (not shown) is applied corresponding to the white drive. In the driving state of the dynamic voltage, the liquid crystal molecules 57 in the liquid crystal layer are deformed close to the twisted alignment state, and the polarizing surface of the incident light passes through the liquid crystal cell, and is rotated by about 90 degrees and passed through the polarizing film 51. That is, you can get a white display.

In the past, in the TN mode, the problem of lowering the contrast of the front side and the direction of the oblique direction was reduced. In the Japanese Patent No. 2587398, in order to improve the viewing angle contrast in the oblique direction, high contrast can be obtained by compensating the liquid crystal cell and the optical anisotropic layer, but the crossing axes 52 and 62 of the upper and lower polarizing films 51 and 61 cross. The angle system is 90° orthogonal to the front, and the situation observed from the oblique direction is not fully considered from the 90° offset system, because the main factor causes light leakage in the oblique direction, which reduces the problem of contrast. . In the liquid crystal display device of the second aspect of the present invention, which is configured as shown in FIG. 3, the Re/Rth system in each of R, G, and B is inconsistent and has optical characteristics satisfying specific conditions. The transparent film 53 (or 63), the light leakage in the oblique direction in the black display is reduced, and the contrast is improved.

More specifically, in the second aspect of the present invention, by using a transparent film having the above optical characteristics, light of respective wavelengths of R, G, and B in the incident oblique direction can be different for each wavelength. And the hysteresis value is optically compensated. Further, the optically anisotropic layer (Fig. 3, 55 and 59) in which the liquid crystal compound is aligned is fixed by the alignment average direction in the transparent film side interface of the molecular symmetry axis of the liquid crystal compound, and the transparent film. The slow phase axis is configured to be cross-over at 0 or 90 degrees, and the unique compensation of the TN alignment can be performed at all wavelengths. As a result, the contrast of the viewing angle of the black display is particularly improved, and the coloring system in the viewing direction of the black display is also particularly alleviated.

Here, in the present specification, the wavelengths of R, G, and B are such that R is a wavelength of 650 nm, G is a wavelength of 550 nm, and B is a wavelength of 450 nm. The wavelengths of R, G, and B do not necessarily have to be represented by the wavelength, and it is conceivable to specify an appropriate wavelength for exhibiting the optical characteristics of the second aspect of the present invention.

In particular, the second aspect of the present invention focuses on Re/Rth of the ratio of Re to Rth of the transparent film. Just because the value of Re/Rth is the axis of the two inherent polarizations in the propagation of the birefringent medium in the oblique direction. Therefore, the axis of the two inherent polarizations in the propagation of the light in the oblique direction of the birefringent medium corresponds to the direction of the major axis and the minor axis of the profile produced by the refractive index 楕 round body when it is cut in the normal direction of the light proceeding direction. . Fig. 4 is a view showing the direction of one axis of one of two inherent polarizations in the case where the forward light is incident in the oblique direction in the transparent film used in the second aspect of the present invention, that is, the case An example of the result of calculating the relationship between the angle of the slow phase axis and Re/Rth. Further, in Fig. 4, the direction of propagation of light is set to azimuth angle = 45 degrees and polar angle = 34 degrees. As shown in Fig. 4, the angle of the slow phase axis is not dependent on the wavelength of the incident light, and is basically determined according to Re/Rth. How the polarization state of the incident light passing through the transparent film changes is mainly determined by the retardation axis orientation of the transparent film and the hysteresis value of the transparent film, but in the prior art, regardless of the wavelengths of R, G, and B, The values of /Rth are substantially the same, that is, the angles of the slow phase axes are substantially the same. On the other hand, in the second aspect of the present invention, the respective wavelengths of R, G, and B are determined by the relationship of Re/Rth, and the retardation axis and the hysteresis value which are mainly factors for determining the change in the polarization state are tied to each other. The wavelengths of R, G, and B are optimized. Then, the light passing through the oblique direction of the transparent film is an optically anisotropic layer fixed by the alignment of the liquid crystal compound, and then the liquid crystal layer of the alignment is bent, and at the same time, the hysteresis value of the wavelength and the upper and lower polarizing films are compensated at the same time. The value of the Re/Rth of the transparent film is adjusted according to the wavelength, as the so-called two main factors of the apparent transmission axis shifting from the front side. Specifically, the larger the wavelength, the larger the Re/Rth of the transparent film, and the polarization state in R, G, and B which occurs due to the wavelength dispersion of the optical anisotropic layer and the liquid crystal cell layer may not be different. As a result, it is possible to fully compensate and reduce the reduction in contrast. If R, G, and B represent the entire visible light region to determine the parameters of the film, so-called substantially complete compensation can be performed for the entire visible light region.

Here, define the polar angle and azimuth. The polar angle is from the normal direction of the film surface, that is, the inclination of the z-axis in Fig. 3, for example, the normal direction of the film surface is a direction of polar angle = 0 degrees. The azimuth angle indicates the direction in which the positive x-axis direction is the reference and the direction of rotation in the counterclockwise direction. For example, the direction in which the x-axis is positive is a direction in which the azimuth angle is 0 degrees, and the direction in which the y-axis is positive is a direction in which the azimuth angle is 90 degrees. The black light leakage is the most important problem. The oblique direction is because the polarizing axis of the polarizing layer is ±45, so it mainly refers to the case where the polar angle is not 0 degrees, and the azimuth angle is 0 degrees, 90 degrees, 180 degrees, 270. Degree of situation.

In order to explain in more detail the action of the second aspect of the present invention, the state of polarization of light incident on the liquid crystal display device is shown on the Poincare sphere in FIGS. 5 and 6. Further, in Fig. 5, the S2 axis is a view perpendicularly penetrating from the plane of the paper, and Fig. 5 is a view of the Bowingkale sphere viewed from the positive direction of the S2 axis. Further, since the fifth figure is a plane, the displacement of the point before and after the change of the polarization state is indicated by the arrow of the straight line in the figure, but actually the change of the polarization state by the liquid crystal layer or the transparent film is caused. The Bowingkale ball is represented by a specific angle of rotation on a specific axis determined by its respective optical characteristics.

In the configuration of the conventional TN mode liquid crystal display device shown in Fig. 7, the transparent films 53 and 63 having the wavelength dependence of Re/Rth are not disposed, and the optical anisotropic layer is disposed, for example. Transparent supports 73 and 83 of 55 and 59. The transparent supports 73 and 83 are intended to support the optically anisotropic layers 55 and 59 and are composed of a general polymer film. Therefore, as shown by the transparent films 53 and 63 used in the liquid crystal display device of Fig. 3, there is no wavelength dependency on Re/Rth, and the same Re is also displayed in the wavelength of any of R, G, and B. Rth. As a result, in the conventional TN mode liquid crystal display device, when the voltage is applied, that is, when the black display is performed, the front liquid crystal cell and the front side retardation value of the optical anisotropic layer are offset, and although black is obtained, The problem that the light leakage displayed in black in the oblique direction cannot be completely suppressed. Furthermore, as a result, since sufficient viewing angle contrast is not obtained and compensation cannot be performed in all wavelengths, there is a problem of coloring.

In Fig. 5, the polarization state of the R incident light is represented by IR, the polarization state of the G incident light is represented by IG, and the polarization state of the B incident light is represented by IB. Further, in the configuration of the conventional liquid crystal display device of the TN mode, in the seventh embodiment, the transparent supports 73 and 83 are set to have Re=96 nm and Rth=58 nm in any of R, G, and B wavelengths, and the optical directions are different. The layers 55 and 59 were set to Re = 30 nm for calculation. First, in the fifth diagram, IR1, IG1, and IB1 are the same in the polarized state after the polarizing film 61. When the change in the B-light polarization state is noted, it is 60 from the left. It is understood that the incident B light is shifted by the optical anisotropic layer 59 by the polarization state IB2 passing through the transparent support 83. As a result, the positions of the final transition states IR6, IG6, and IB6 of the incident light of R, G, and B are not uniform. For this reason, while the left and right black light leaks are obtained, the angle of view is completely insufficient, and since the light of all wavelengths cannot be blocked at the same time, the black system is dyed.

In the second aspect of the present invention, the viewing angle contrast of the liquid crystal display device of the TN mode is improved by arranging a transparent film which exhibits specific optical characteristics. For a more detailed description, the results of the polarization states of the R, G, and B lights of the liquid crystal display device passing through the TN mode shown in FIG. 3 are calculated and displayed on the Bowingka ball of FIG. Fig. 6 is a view showing changes in the polarization states of light incident from the lower 60° with respect to changes in R, G, and B. In the figure, the polarization state of the R incident light is represented by IR, the polarization state of the G incident light is represented by IG, and the polarization state of the B incident light is represented by IB. Further, the transparent films 63 and 53 are set such that Re/Rth (450 nm) is 0.17 at a wavelength of 450 nm, Re/Rth (550 nm) at a wavelength of 550 nm is 0.28, and Re/Rth (650 nm) at a wavelength of 650 nm is 0.39, and The Rth was 160 nm at a wavelength of 550 nm and was calculated. The Re of the optically anisotropic layers 55 and 59 is set to the same value as the Bowingka ball shown in Fig. 5.

In the case shown in Fig. 6, after the incident R light, G light, and B light pass through the transparent films 63 and 53, all of them are in the vicinity of S1 = 0, and the Re/Rth wavelength dependence reflecting the transparent film 63 is changed. The polarization state of the sexual offset position. In this case, the shift of the polarization state of the R light, the G light, and the B light due to the wavelength dispersion of the optically anisotropic layers 59 and 55 and the liquid crystal layer 57 can be eliminated. As a result, the light incident from any of the left and right directions can form the same position without depending on the final transition point of the wavelength. Furthermore, as a result, black light leakage in the lower viewing angle can be alleviated, and the contrast viewing angle can be greatly improved.

One of the features of the second aspect of the present invention, using the so-called biaxiality of the transparent film adjacent to the optically anisotropic layer, not only improves the oblique direction, for example, the viewing angle contrast in the direction of the azimuth angle of 270 degrees and the polar angle of 60 degrees. Further, by actively utilizing the relationship between the hysteresis value Re of the transparent film and the wavelength dispersion of the Rth, the black light leakage in the viewing direction is also improved. In particular, in the TN mode, by using an optical compensation film composed of an optically anisotropic layer having a predetermined characteristic and a transparent film having a predetermined characteristic, the viewing angle contrast in all directions can be improved. The effect due to this method is not limited by the display mode of the liquid crystal layer, and can be used for a liquid crystal display device having a liquid crystal layer of any display mode such as TN mode, VA mode, IPS mode, ECB mode, or OCB mode.

Further, the liquid crystal display device according to the second aspect of the present invention is not limited to the configuration shown in Fig. 3, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. Further, as a penetrating type, a cold cathode or a hot cathode fluorescent tube, or a backlight of a light emitting diode, a field emission element, or an electroluminescence element as a light source may be disposed on the back surface.

Further, the liquid crystal display device according to the second aspect of the present invention includes a portrait direct view type, a portrait projection type, or a light modulation type. The present invention is particularly effective in the form of an active matrix liquid crystal display device which is suitable for a three-terminal or two-terminal semiconductor element such as a TFT or MIM. Of course, the aspect of the passive matrix liquid crystal display device represented by the STN type called time-division driving is also effective.

Next, the member used in the liquid crystal display device according to the second aspect of the present invention, particularly the optical compensation film according to the second aspect of the present invention, will be described in detail with reference to optical characteristics, raw materials, manufacturing methods, and the like.

[Optical compensation film]

The optical compensation film according to the second aspect of the present invention can contribute to an increase in viewing angle contrast of a liquid crystal display device, particularly a TN mode liquid crystal display device, and a reduction in color shift depending on a viewing angle. The optical compensation film according to the second aspect of the present invention may be disposed between the polarizing plate on the observer side and the liquid crystal cell, or between the polarizing plate on the back side and the liquid crystal cell, or both. For example, it can be assembled into a liquid crystal display device as a separate member, or can be provided with a function as a transparent film as a function of a transparent film, and can be assembled to a liquid crystal display device. internal. The optical compensation film according to the second aspect of the present invention has at least two layers of a transparent film and an optically anisotropic layer having optical anisotropy in the plane. Between the transparent film and the optically anisotropic layer, an alignment film for controlling the alignment of the liquid crystalline compound in the optically anisotropic layer may be provided. Further, the transparent film and the optically anisotropic layer may each be composed of two or more layers within a range satisfying the optical characteristics described later. First, each constituent member of the optical compensation film according to the second aspect of the present invention will be described in detail.

[transparent film]

The transparent film constituting the optical compensation film according to the second aspect of the present invention has a ratio of Re to Rth (450 nm) at a wavelength of 450 nm in the visible light region of Re/Rth (550 nm) at a wavelength of 550 nm. 0.95 times, preferably 0.39 to 0.9 times, preferably 0.6 to 0.8 times, and Re/Rth (650 nm) is 1.04 to 2.20 times, preferably 1.1 to 1.9, of Re/Rth (550 nm) at a wavelength of 650 nm. Times, preferably 1.2 to 1.7 times. Further, it is preferable that the Re/Rth systems of each of R, G, and B are in the range of 0.1 to 0.8.

Further, the hysteresis value (Rth) in the thickness direction of the entire transparent film also has a function of eliminating the hysteresis value of the liquid crystal layer in the thickness direction during black display. Therefore, the preferred range of each liquid crystal layer is also It is different, but in general, it is preferable that Rth is 70 nm to 400 nm at a wavelength of 550 nm. More specifically, for example, a liquid crystal cell for optically compensating the TN mode (for example, a TN mode of a liquid crystal layer having a thickness d (micrometer) and a refractive index anisotropy Δn of Δn.d of 0.2 to 1.5 μm. In the case of a liquid crystal cell, it is preferably 10 to 200 nm, preferably 20 nm to 150 nm, and more preferably 40 to 120 nm. Further, the Re hysteresis value is generally 20 to 200 nm, preferably 30 to 170 nm, more preferably 80 to 130 nm.

Further, the thickness of the transparent film is not particularly limited, but is preferably 110 μm or less, preferably 40 to 110 μm, more preferably 80 to 110 μm.

The transparent film is prepared by adjusting the material to the desired range by selecting a raw material, a blending amount thereof, a production condition, etc., and a transparent film satisfying the optical characteristics of Re and Rth can be produced. Specifically, a method of mixing two or more kinds of polymers having different wavelength dispersions is a method of adding an additive capable of being absorbed in an ultraviolet region or an infrared region to control wavelength dispersion of visible light; and being capable of being absorbed in an ultraviolet region or an infrared region. a method of aligning the thickness direction, the extending direction or the non-extension direction of the structural film; coating or laminating a polymer having a different wavelength dispersion to adjust the wavelength dispersion; and imparting unevenness to the thickness direction by the film manufacturing step The temperature distribution or the intensity distribution of ultraviolet rays, the adjustment of the alignment property or the uniformity of the material to control the wavelength dispersion method, and the like.

The raw material of the above transparent film is not particularly limited. For example, it may be an extended birefringent polymer film or an optically anisotropic layer formed by fixing a liquid crystal compound to a specific alignment. Further, the transparent film is not limited to a single layer structure, and may have a laminated structure having a plurality of laminated layers. It is preferable that the raw material of each layer of the laminated structure is not the same kind, and for example, it may be a laminated body of an optically anisotropic layer composed of a polymer film and a liquid crystal compound. When the thickness is considered in the laminated structural form, it is preferable that the coating type laminated system including the layer formed by coating is more than the laminated body of the polymer stretched film.

In the case where a liquid crystalline compound is used in the production of the above transparent film, since the liquid crystalline compound has various alignment forms, the optically anisotropic layer formed by fixing the liquid crystalline compound in a specific alignment state is formed by forming a single layer or The layers of the plurality of layers are found to reveal the desired optical properties. That is, the transparent film may be formed of a support and an optically anisotropic layer in which one or more layers are formed on the support. The hysteresis value of the entire transparent film of this aspect can be adjusted according to the optical anisotropy of the optically anisotropic layer. The liquid crystalline compound can be classified into a rod-like liquid crystalline compound and a discotic liquid crystalline compound depending on the shape of the molecule. In addition, each has a low molecular and polymer type, and can be used. When a liquid crystal compound is used for the production of the transparent film, a rod-like liquid crystal compound or a discotic liquid crystal compound is preferably used, and a rod-like liquid crystal compound having a polymerizable group or a polymerizable group is used. A discotic liquid crystalline compound is preferred.

Further, the transparent film may be composed of a polymer film. The polymer film may be an extended polymer film or a coated polymer layer or a polymer film. The material of the polymer film is generally a synthetic polymer (for example, polycarbonate, polyfluorene, polyether oxime, polyacrylate, polymethacrylate, norbornene resin, triacetyl cellulose). Further, a composition of a rod-like compound having an aromatic ring (specifically, an aromatic compound having two aromatic rings) is added to the deuterated cellulose, and a deuterated cellulose-based film as a film can be formed. By adjusting the type, amount of addition, and stretching conditions of the above-mentioned aromatic compound, a polymer film having desired optical characteristics can be produced.

"Sulphide Cellulose Film"

Further, a cellulose oxide film which can be used as the above transparent film can be used in detail.

By adjusting the kind and amount of the rod-like compound having an aromatic ring to be added (specifically, an aromatic compound having two aromatic rings), or the production conditions (for example, elongation conditions of the film), it is possible to produce the above-mentioned transparency. A cellulose acetate film of optical properties of the film. Further, the protective film of the polarizing plate is generally composed of a deuterated cellulose film. When the above-described deuterated cellulose film is used as a protective film for one of the polarizing plates, the optical compensation function can be added to the polarizing plate without increasing the number of constituent elements of the polarizing plate.

Further, when a rod-like compound having two or more wavelengths having a maximum absorption wavelength (λmax) shorter than 250 nm is used in the ultraviolet absorption spectrum, a Re/Rth ratio which differs depending on the wavelength can be obtained.

Well-known raw materials can be used as the raw material of the deuterated cellulose (for example, refer to the Invention Association published technique 2001-1745). Further, the synthesis of deuterated cellulose can also be carried out by a well-known method (for example, refer to Odida, Wood Chemistry, 180-190 (Kyoritsu, 1968)). The average degree of polymerization of deuterated cellulose is preferably 200 to 700, more preferably 250 to 500, and most preferably 250 to 350. Further, the deuterated cellulose to be used is preferably a narrow molecular weight distribution of Mw/Mn (Mw is a mass average molecular weight and Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mw/Mn is preferably 1.5 to 5.0, 2.0 to 4.5 is preferred, and 3.0 to 4.0 is preferred.

The fluorenyl group of the deuterated cellulose film is not particularly limited, and it is preferably an acetamino group or a propyl group, particularly an acetamidine group. The degree of substitution of all sulfhydryl groups is preferably 2.7 to 3.0, and preferably 2.8 to 2.95. In the present specification, the degree of substitution of the fluorenyl group is a value calculated in accordance with ASTM D817. The oxime group is preferably an acetamidine group. In the case of using cellulose acetate having a thiol group as the acetamidine group, the degree of acetification is preferably 59.0 to 62.5%, preferably 59.0 to 61.5%. When the degree of vinegarization is within this range, Re will not form a larger value than desired, and the in-plane variation will be small, and the change in hysteresis value due to temperature and humidity will be small. Further, the degree of substitution of the thiol group at the 6-position is preferably 0.9 or more from the viewpoint of suppressing the deviation of Re and Rth.

Further, when the cellulose acetate having a different degree of acetification is used in a certain range and different from each other, the wavelength dispersion characteristics can be adjusted by using the wavelength dispersion characteristics of the hysteresis value to adjust the wavelength dispersion characteristics. This method is described in detail in JP-A-2001-253971, the difference between the degree of acetification of cellulose acetate having the maximum degree of acetification (Ac1) and cellulose acetate having the smallest degree of acetification (Ac2) (Ac1- Ac2) is preferably 2.0 to 6.0% (2.0% ≦Ac1-Ac2 ≦ 6.0%). The average degree of acetification of the cellulose acetate mixture is preferably 55.0 to 61.5%. Further, the ratio of the cellulose acetate having the maximum viscosity average degree of polymerization (P1) to the viscosity average degree of polymerization (P1/P2) of the cellulose acetate having the lowest viscosity average degree of polymerization (P2) is 1 or more and lower than 2 (1≦P1/P2<2) is preferred. The viscosity average polymerization degree of the cellulose acetate mixture is preferably from 250 to 500, preferably from 250 to 400.

Hysteresis value control agent

The deuterated cellulose film preferably contains a rod-like compound having at least one aromatic ring as a hysteresis value controlling agent. The rod-like compound is preferably a linear molecular structure. The linear molecular structure means that the molecular structure of the rod-like compound is a straight line in the thermodynamically most stable structure. The thermodynamically most stable structure can be calculated by calculation of crystal structure or molecular orbital calculation. For example, molecular orbital calculation software (for example, manufactured by WinMOPAC2000, Fujitsu Co., Ltd.) can be used to perform molecular orbital calculation to determine a molecular structure in which the heat of formation of a compound is minimized. When the molecular structure is a straight line, the thermodynamically most stable structure obtained by the above calculation means that the angle of the molecular structure main chain is 140 degrees or more.

The rod-like compound having at least two aromatic rings is preferably a compound represented by the following formula (1).

General formula (1): Ar ¹ -L ¹ -Ar ²

In the above formula (1), Ar ¹ and Ar ² each independently represent an aromatic group. L ¹ is a divalent linking group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, -O-, -CO-, and a combination thereof.

In the present specification, the aromatic group contains an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.

The aryl group and the substituted aryl group are more preferred than the aromatic heterocyclic group and the substituted aromatic heterocyclic group. The heterocyclic ring system of the aromatic heterocyclic group is generally unsaturated. The aromatic heterocyclic ring is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, and more preferably a 5-membered ring or a 6-membered ring. Aromatic heterocyclic systems generally have the most amount of double bonds. The hetero atom is preferably a nitrogen atom, an oxygen atom or a sulfur atom, and more preferably a nitrogen atom or a sulfur atom. Examples of the aromatic heterocyclic ring include a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, a pyrazole ring, a furazan ring, and a triazole ring. Piper ring, pyridine ring, hydrazine Ring, pyrimidine ring, pyridyl Ring, and 1,3,5-three ring.

The aromatic ring-based aromatic ring system is a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring, and a pyridyl group. The ring is preferred and the benzene ring is especially good.

Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, a cyano group, an amine group, an alkylamine group (for example, a methylamine). Base, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, amine carbenyl group, alkylamine carbenyl group (for example, N-methylaminecarbamyl group, N- Ethylamine, mercapto, N,N-dimethylamine, mercapto, sulfonyl, alkylamine sulfonyl (for example, N-methylamine sulfonyl, N-ethylamine sulfonate) Base, N,N-dimethylaminesulfonyl), ureido, alkylureido (eg, N-methylureido, N,N-dimethylureido, N,N,N'-three Methylurea), alkyl (for example, methyl, ethyl, propyl, butyl, pentyl, heptyl, octyl, isopropyl, s-butyl, t-pentyl, cyclohexyl, ring Amyl), alkenyl (eg, vinyl, allyl, hexenyl), alkynyl (eg, ethynyl, butynyl), fluorenyl (eg, methyl, ethyl, propyl) , hexanyl, lauryl), anthraceneoxy (eg, ethoxylated, butyloxy, hexyloxy, lauryloxy), alkoxy (eg, methoxy, ethoxy, propoxy, butoxy, pentyloxy, heptyloxy, octyloxy), aryloxy (eg, phenoxy), alkoxycarbonyl (eg, Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentyloxycarbonyl, heptyloxycarbonyl), aryloxycarbonyl (eg phenoxycarbonyl), alkoxycarbonylamino (eg, butoxycarbonylamino, hexyloxycarbonylamino), alkylthio (eg, methylthio, ethylthio, propylthio, butylthio, pentylthio, heptylthio, octylthio) Alkylthio (for example, phenylthio), alkylsulfonyl (for example, methylsulfonyl, ethylsulfonyl, propylsulfonyl, butylsulfonyl, pentylsulfonyl) a base, a heptylsulfonyl group, an octylsulfonyl group, an amidino group (for example, acetamide, butylamine, hexamethyleneamine, lauryl sulfhydryl) and a non-aromatic heterocyclic group (for example) , morpholinyl, pyridyl base).

The substituent of the substituted aryl group and the substituted aromatic heterocyclic group is a halogen atom, a cyano group, a carboxyl group, a hydroxyl group, an amine group, an alkyl group-substituted amine group, a fluorenyl group, a decyloxy group, a decylamino group or an alkoxycarbonyl group. Alkoxy, alkylthio and alkyl are preferred.

The alkyl moiety of the alkylamino group, the alkoxycarbonyl group, the alkoxy group and the alkylthio group and the alkyl group may further contain a substituent. Examples of the substituent of the alkyl moiety and the alkyl group may include a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amine group, an alkylamino group, a nitro group, a sulfo group, an amine methyl group, an alkylamine methyl group, Aminesulfonyl, alkylamine sulfonyl, ureido, alkylureido, alkenyl, alkynyl, decyl, decyloxy, alkoxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl An alkoxycarbonylamino group, an alkylthio group, an arylthio group, an alkylsulfonyl group, a decylamino group, and a non-aromatic heterocyclic group. The substituent of the alkyl moiety and the alkyl group is preferably a halogen atom, a hydroxyl group, an amine group, an alkylamino group, a decyl group, a decyloxy group, a decylamino group, an alkoxycarbonyl group or an alkoxy group.

L ¹ is a divalent linking group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, -O-, -CO-, and a combination thereof.

The alkylene group may also have a cyclic structure. The cyclic alkyl group is preferably a cyclohexylene group or a 1,4-cyclohexylene group. The chain alkyl group is preferably a linear alkyl group rather than a branched alkyl group.

The number of carbon atoms of the alkyl group is preferably from 1 to 20, more preferably from 1 to 15, more preferably from 1 to 10, still more preferably from 1 to 8, most preferably from 1 to 6.

The alkenyl group and the alkynyl group have a chain structure, preferably a ring structure, and a chain structure having a linear structure rather than a branch. The number of carbon atoms of the alkenyl group and the alkynylene group is preferably 2 to 10, preferably 2 to 8, more preferably 2 to 6, more preferably 2 to 4, most preferably 2 (vinylidene or stretching). Ethynyl). The arylene group is preferably 6 to 20, more preferably 6 to 16, more preferably 6 to 12 in terms of a carbon number.

An example of a divalent linking group composed by combination is exemplified.

L-1: -O-CO-alkylene-CO-O- L-2: -CO-O-alkylene-O-CO- L-3: -O-CO-alkenyl-CO-O - L-4: -CO-O-Extend alkenyl-O-CO- L-5: -O-CO-exetylene-CO-O- L-6:-CO-O-exetylene-O- CO- L-7:-O-CO-arylene-CO-O- L-8:-CO-O-arylene-O-CO- L-9:-O-CO-arylene-CO -O- L-10:-CO-O-arylene-O-CO-

In the molecular structure of the formula (1), the angle formed by the holding of L ¹ , Ar ¹ and Ar ² is preferably 140 degrees or more. The rod-like compound is preferably a compound represented by the following formula (2).

Formula (2): Ar ¹ -L ² -X-L ³ -Ar ²

In the above formula (II), Ar ¹ and Ar ² each independently form an aromatic group. The definition and examples of the aromatic group are the same as those of Ar ¹ and Ar ^{2 of the} formula (I).

In the formula (II), L ² and L ³ are divalent linking groups selected from the group consisting of an alkyl group, an -O- group, a -CO- group, and a combination thereof. The alkylene group is preferably a chain structure rather than a ring structure, and the linear structure is more preferable than the branched chain structure.

The alkyl group has preferably 1 to 10 carbon atoms, preferably 1 to 8, more preferably 1 to 6, more preferably 1 to 4, 1 or 2 (methylene or ethyl). good. L ² and L ³ are particularly preferably -O-CO- or -CO-O-.

In the formula (2), the X system is a 1,4-cyclohexylene group, a vinylidene group or an exetylene group.

Specific examples of the compound represented by the formula (1) are shown below.

Specific examples (1) to (34), (41), and (42) have two asymmetric carbon atoms at the 1-position and 4-position of the cyclohexane ring. However, the specific examples (1), (4) to (34), (41), and (42) have no optical isomers (optically active) due to their symmetrical meso-type molecular structure, and only geometric isomerism Objects (cis and inversion) exist. The cis-type (1-trans) and the inverse-type (1-cis) of the specific example (1) are as follows.

As described above, the rod-like compound preferably has a linear molecular structure. Therefore, the cis is better than the inverse. Specific examples (2) and (3) include optical isomers (a total of four isomers) in addition to geometric isomers. In geometric isomers, the same is preferred as the inversion. There is no particular advantage in the optical isomers, and it may be any of the D-isomer, the L-isomer or the racemate.

In the specific examples (43) to (45), the center vinylidene bond system produces a cis-type and an inverse type.

For the same reason as above, the cis is preferable to the inverse.

Further, a preferred compound which can be used as a hysteresis value controlling agent is as shown below.

In the ultraviolet absorption spectrum of the solution, a rod-like compound having two or more maximum absorption wavelengths (λmax) shorter than 250 nm may be used in combination as the hysteresis value controlling agent. The rod-like compound was synthesized by the method described in the literature. For literature, for example, Mol. Cryst. Liq. Cryst., Vol. 53, p. 229 (1979), Vol. 89, p. 93 (1982), vol. 145, p. 111 (1987). , Vol. 170, p. 43 (1989), J. Am. Chem. Soc., vol. 113, p. 1349 (1991), vol. 118, p. 5346 (1996), same Vol. 92, p. 1582 (1970), J. Org. Chem., vol. 40, p. 420 (1975), Tetrahedron, vol. 48, p. 16, p. 3437 (1992).

The amount of the hysteresis value controlling agent to be added is preferably from 0.1 to 30% by mass, and preferably from 0.5 to 20% by mass, based on the amount of the polymer.

The aromatic compound is preferably used in an amount of 0.01 to 20 parts by mass based on 100 parts by mass of the deuterated cellulose. The aromatic compound is preferably used in an amount of 0.05 to 15 parts by mass, preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the deuterated cellulose. Two or more compounds may be used in combination.

[Wavelength dispersion adjuster]

A compound which adjusts the wavelength dispersion of the deuterated cellulose film will be described. The wavelength dispersion of the deuterated cellulose film can be adjusted by various methods. For example, the adjustment can be carried out by including a compound having absorption in the ultraviolet region of 200 to 400 nm in the film. The preferred addition amount of the compound varies depending on the type of the compound to be used or according to the adjustment, and a deuterated cellulose film having the optical characteristics required for the above transparent film can be produced by using about 0.01 to 30% by mass.

The values of Re and Rth of the deuterated cellulose film are generally wavelength dispersion characteristics which are larger on the long wavelength side than on the shorter wavelength side. Therefore, by increasing Re(λ) and Rth(λ) on the relatively small short-wavelength side, wavelength dispersion can be required to be smooth. On the other hand, a compound having an absorption value in the ultraviolet field of 200 to 400 nm has a wavelength dispersion characteristic in which the absorbance at the long wavelength side is larger than that on the short wavelength side. When the compound itself is isotropically present inside the deuterated cellulose film, the birefringence of the compound itself, and further the wavelengths of Re(λ) and Rth(λ) can be dispersed, and the wavelength is dispersed similarly to the wavelength of the absorbance. Larger than the short wavelength side.

Therefore, as described above, by using an assumed absorption value in the ultraviolet field of 200 to 400 nm, and the Re(λ) and Rth (%) wavelength dispersion ratio of the compound itself is larger than the short wavelength side, the deuterated cellulose can be prepared. The wavelengths of Re and Rth of the film are dispersed. For this reason, it is required to adjust the wavelength-dispersed compound to be sufficiently uniformly compatible with the cellulose-deposited cellulose. The absorption band of the ultraviolet field of these compounds is preferably in the range of 200 to 400 nm, preferably 220 to 395 nm, and more preferably 240 to 390 nm.

In addition, in recent years, liquid crystal display devices such as televisions, personal computers, and mobile portable terminals have been required to have higher transmittance for optical members used in liquid crystal display devices in order to increase brightness with less power. In this case, in the case where a compound having an absorption value in the ultraviolet field of 200 to 400 nm is added to the deuterated cellulose film, the spectral transmittance is required to be excellent. In the deuterated cellulose film of the present invention, the spectral transmittance at a wavelength of 380 nm is 45% or more and 95% or less, and the spectral transmittance at a wavelength of 350 nm is preferably 10% or less.

As described above, the wavelength dispersion adjusting agent preferably used in the present invention preferably has a molecular weight of from 250 to 1,000 from the viewpoint of volatilization. It is preferably 260 to 800, more preferably 270 to 800, and particularly preferably 300 to 800. Within the range of such molecular weights, it may be a specific monomer structure, and the monomer unit may have a complex bonded oligomer structure or a polymer structure.

The wavelength dispersion adjusting agent is preferably not dispersed in the process of casting and drying the paste produced by the deuterated cellulose film.

(compound addition amount)

The amount of the wavelength dispersion adjusting agent to be preferably used in the present invention is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, and particularly preferably 0.2 to 10% by mass.

(Method of compound addition)

Further, these wavelength dispersion adjusting agents may be used singly or in combination of two or more kinds of compounds in any ratio.

The period in which these wavelength dispersion adjusters are added may be carried out at any stage in the dope preparation step or at the end of the dope preparation step.

Specific examples of the wavelength dispersion adjusting agent to be preferably used in the present invention include, for example, a benzotriazole-based compound, a benzophenone-based compound, a cyano group-containing compound, a hydroxybenzophenone-based compound, and a salicylate-based compound. A compound, a nickel salt-salt compound or the like, but the present invention is not limited by such compounds.

It is preferred to use a benzotriazole-based compound as a wavelength dispersion adjusting agent as represented by the general formula (3).

General formula (3) Q ¹ -Q ² -OH (wherein Q ¹ represents a nitrogen-containing aromatic heterocyclic ring, and Q ² represents an aromatic ring)

Q ¹ represents a nitrogen-containing aromatic heterocyclic ring, preferably a nitrogen-containing aromatic heterocyclic ring of 5 to 7 members, more preferably a nitrogen-containing aromatic heterocyclic ring of 5 to 6 members, and examples thereof include imidazole and pyrazole. Triazole, tetrazole, thiazole, oxazole, selenazole, benzotriazole, benzothiazole, benzoxazole, benzoselenazole, thiadiazole, oxadiazole, naphthalene thiazole, naphthazole, benzene Imidazole, hydrazine, pyridine, pyridyl Pyrimidine ,three , triterpenoid, tetraazide, etc., more preferably a nitrogen-containing aromatic heterocyclic ring of 5 members, specifically, imidazole, pyrazole, triazole, tetrazole, thiazole, oxazole, benzotriazole, Benzothiazole, benzoxazole, thiadiazole, oxadiazole are preferred, and benzotriazole is particularly preferred. The nitrogen-containing aromatic heterocyclic ring represented by Q ¹ may further contain a substituent, and the substituent T to be described later may be applied. Further, in the case where the substituent is plural, each of the condensed rings may further form a ring.

The aromatic ring represented by Q ² may be an aromatic hydrocarbon ring or an aromatic hetero ring. Moreover, they may also be single rings, and may also form condensation rings with other rings. The aromatic hydrocarbon ring is preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring or a naphthalene ring), and more preferably a carbon number of 6 to 20. The aromatic hydrocarbon ring is more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms. More preferably, it is a benzene ring.

The aromatic heterocyclic ring is preferably an aromatic heterocyclic ring containing a fluorine atom or a sulfur atom. Specific examples of the heterocyclic ring include thiophene, imidazole, pyrazole, pyridine, and pyridyl. 哒 Triazole, three , hydrazine, carbazole, hydrazine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, hydrazine , naphthalene ingot, quinoxaline, quinazoline, porphyrin, acridine, acridine, phenanthroline, phenanthrene , tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, tetralazide. The aromatic heterocyclic ring is preferably pyridine or three ,quinoline. The aromatic ring representing Q ² is preferably an aromatic hydrocarbon ring, more preferably a naphthalene ring or a benzene ring, and particularly preferably a benzene ring. Q ² may further contain a substituent, and a substituent T to be described later is preferred. The substituent T is, for example, an alkyl group (for example, preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably having 1 to 8 carbon atoms, such as methyl, ethyl or isopropyl groups). , a third butyl group, an n-octyl group, a n-decyl group, a n-hexadecyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, etc.), an alkenyl group (for example, preferably a carbon number of 2 to 20, more preferably a carbon atom number of 2 to 12, a particularly preferred carbon number of 2 to 8, such as a vinyl group, an allyl group, a 2-butenyl group, a 3-pentenyl group, etc., an alkynyl group (exemplified by a carbon atom) a number of 2 to 20, more preferably a carbon number of 2 to 12, a particularly preferred carbon number of 2 to 8, such as a propargyl group, a 3-pentynyl group, or the like, an aryl group (for example, preferably a carbon number of 6) ~30, more preferably a carbon number of 6 to 20, a particularly preferred carbon number of 6 to 12, such as a phenyl group, a p-tolyl group, a naphthyl group or the like, a substituted or unsubstituted amine group (for example, preferably The number of carbon atoms is 0 to 20, more preferably 0 to 10, and the number of carbon atoms is 0 to 6, such as an amine group, a methylamino group, a dimethylamino group, a diethylamino group, and a dipentyl group. Amino group, etc.), alkoxy group (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and 1 to 12 carbon atoms) 8, for example, methoxy, ethoxy, butoxy, etc.), aryloxy (exemplified by preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 carbon atoms) ~12, such as phenoxy, 2-naphthyloxy, etc.), fluorenyl (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 1 to 12 carbon atoms) , for example, an ethyl fluorenyl group, a benzamidine group, a decyl group, a trimethyl ethane group, etc.), an alkoxycarbonyl group (exemplified by preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms). Particularly preferred is a carbon number of 2 to 12, such as a methoxycarbonyl group or an ethoxycarbonyl group, and an aryloxycarbonyl group (exemplified by preferably having 7 to 20 carbon atoms and more preferably 7 to 16 carbon atoms). Particularly preferred is a carbon number of 7 to 10, such as a phenoxycarbonyl group, or a decyloxy group (exemplified by preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably having 2 to 16 carbon atoms). 2 to 10, for example, an oximeoxy group, a benzylideneoxy group, etc.), a guanamine group (for example, preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and a particularly good carbon number) 2 to 10, for example, an ethoxymethylamino group, a benzhydrylamino group, etc.), an alkoxycarbonylamine group (for example, preferably 2 to 2 carbon atoms) 0, more preferably a carbon number of 2 to 16, a particularly preferred carbon number of 2 to 12, such as a methoxycarbonylamino group, or an aryloxycarbonylamino group (for example, preferably a carbon number of 7 to 20) More preferably, the number of carbon atoms is 7 to 16, the number of carbon atoms is 7 to 12, such as phenoxycarbonylamine, etc., and the sulfonylamino group (for example, preferably having 1 to 20 carbon atoms) It is a carbon number of 1 to 16, a particularly good carbon number of 1 to 12, such as a methanesulfonylamino group, a benzosulfonylamino group, etc., an alkylamine sulfonyl group and an arylamine sulfonyl group (for example Preferably, the number of carbon atoms is 0 to 20, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as an amine sulfonyl group, a methimsulfonyl group, a dimethylamine sulfonyl group, Phenylamine sulfonyl group, etc., an amine carbenyl group (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 1 to 12 carbon atoms, such as amine formazan) a group, a methylamine, a methylamine, a phenylamine, a phenylamine, a thiol group, etc., an alkylthio group (for example, preferably a carbon number of 1 to 20, more preferably a carbon number of 1 to 16) , particularly preferred is a carbon number of 1 to 12, such as methylthio, ethylthio, etc.), an arylthio group (for example, preferably 6 to 20 carbon atoms, more preferably carbon) The atomic number is 6 to 16, the particularly preferred carbon number is 6 to 12, for example, a phenylthio group, etc., and the alkylsulfonyl group is an arylsulfonyl group (for example, the number of carbon atoms is preferably from 1 to 20, more preferably, a carbon number of 1 to 16, a particularly preferred carbon number of 1 to 12, such as a methylsulfonyl group, a toluenesulfonyl group, etc., an alkylsulfinyl group and an arylsulfinyl group (exemplified by carbon) The number of atoms is 1 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as sulfinyl group, benzosulfinyl group, etc., and urea group (for example, preferably The number of carbon atoms is 1 to 20, more preferably, the number of carbon atoms is 1 to 16, the number of carbon atoms is 1 to 12, such as urea group, methylurea group, phenylureido group, etc., and guanidinium phosphate group (for example, Preferably, the number of carbon atoms is 1 to 20, more preferably, the number of carbon atoms is 1 to 16, and the number of carbon atoms is preferably 1 to 12, such as diethylphosphonium amide, phenylphosphonium amide, etc., hydroxyl group, hydrogen Sulfur group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfonyl group, carboxyl group, nitro group, hydroxamic acid group, sulfinyl group, fluorenyl group, imido group, heterocyclic ring The base (for example, preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and a hetero atom such as a nitrogen atom) , an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidinyl, morpholinyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, etc.) And a decyl group (for example, preferably, the number of carbon atoms is 3 to 40, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, for example, trimethyl decyl group, triphenyl decyl group, etc.) )Wait. These substituents may be further substituted. Further, in the case where the substituent is two or more, they may be the same or different. Also, in some cases, they may be connected to each other to form a loop.

Among the compounds represented by the formula (3), a compound represented by the following formula (3-A) is particularly preferred.

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or a substituent.

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or a substituent, and the substituent T can be applied to the substituent. Further, such substituents may be further substituted by other substituents, or the substituents may be condensed to each other to form a ring structure.

R ¹ and R ^{3 are} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably a hydrogen atom, An alkyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, more preferably a hydrogen atom or a carbon 1-12 alkyl group, particularly preferably a C 1-12 alkyl group (preferably a carbon number of 4 to 12). .

R ² and R ^{4 are} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably a hydrogen atom, An alkyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, more preferably a hydrogen atom, or a carbon 1-12 alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

R ⁵ and R ^{8 are} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably a hydrogen atom, An alkyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, more preferably a hydrogen atom, or a carbon 1-12 alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

R ⁶ and R ^{7 are} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably a hydrogen atom, An alkyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, more preferably a hydrogen atom or a halogen atom, particularly preferably a hydrogen atom or a chlorine atom.

The compound of the formula (3) is preferably a compound represented by the following formula (3-B).

In the formula, R ¹ , R ³ , R ⁶ and R ⁷ are the same as those of the formula (3-A), and the preferred ranges are also the same.

Specific examples of the compound represented by the formula (3) are shown in the following series, but the present invention is not limited by the following specific examples.

Among the benzotriazole-based compounds shown in the above examples, even in the case of producing a transparent film film of the present invention which does not contain a molecular weight of 320 or less, it has been confirmed that it is advantageous in terms of retention.

Further, the benzophenone compound which is one of the wavelength dispersion adjusting agents used in the second aspect of the present invention is preferably one represented by the formula (4).

In the formula, Q ^{1 a} and Q ^{2 a} represent independent aromatic rings. X represents NR (R represents a hydrogen atom or a substituent), an oxygen atom or a sulfur atom.

The aromatic ring represented by Q ^{1 a} and Q ^{2 a} may be an aromatic hydrocarbon ring or an aromatic hetero ring. Further, they may be monocyclic or may form a condensed ring with other rings. The aromatic hydrocarbon ring represented by Q ^{1 a} and Q ^{2 a} is preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring or a naphthalene ring). More preferably, it is an aromatic hydrocarbon ring having 6 to 20 carbon atoms, more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms. More preferably, it is a benzene ring. The aromatic heterocyclic ring represented by Q ^{1 a} and Q ^{2 a is} preferably an aromatic heterocyclic ring containing at least one of an oxygen atom, a fluorine atom or a sulfur atom. Specific examples of the heterocyclic ring include furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, and pyridyl. 哒 Triazole, three , hydrazine, carbazole, hydrazine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, hydrazine , naphthalene ingot, quinoxaline, quinazoline, porphyrin, acridine, acridine, phenanthroline, phenanthrene , tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, tetraazide and the like. The aromatic heterocyclic ring is preferably pyridine or three ,quinoline. The aromatic ring represented by Q ^{1 a} and Q ^{2 a is} preferably an aromatic hydrocarbon ring, more preferably an aromatic hydrocarbon ring having 6 to 10 carbon atoms, more preferably a substituted or unsubstituted benzene ring. Q ^{1 a} and Q ^{2 a} may further contain a substituent, and the substituent T described later is preferred, but the substituent does not contain a carboxylic acid, a sulfonic acid or a quaternary ammonium salt. Also, where possible, the substituents may be joined to each other to form a ring configuration.

X is NR (R represents a hydrogen atom or a substituent. The substituent may be a substituent T to be described later), an oxygen atom or a sulfur atom, and X is preferably NR (R is preferably a sulfhydryl group or a sulfonyl group, etc. The substituent may be further substituted with) or O, particularly preferably O.

The substituent T is, for example, an alkyl group (for example, preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably having 1 to 8 carbon atoms, such as methyl, ethyl or isopropyl groups). , a third butyl group, an n-octyl group, a n-decyl group, a n-hexadecyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, etc.), an alkenyl group (for example, preferably a carbon number of 2 to 20, more preferably a carbon atom number of 2 to 12, a particularly preferred carbon number of 2 to 8, such as a vinyl group, an allyl group, a 2-butenyl group, a 3-pentenyl group, etc., an alkynyl group (exemplified by a carbon atom) a number of 2 to 20, more preferably a carbon number of 2 to 12, a particularly preferred carbon number of 2 to 8, such as a propargyl group, a 3-pentynyl group, or the like, an aryl group (for example, preferably a carbon number of 6) ~30, more preferably a carbon number of 6 to 20, a particularly preferred carbon number of 6 to 12, such as a phenyl group, a p-tolyl group, a naphthyl group or the like, a substituted or unsubstituted amine group (for example, preferably The number of carbon atoms is 0 to 20, more preferably 0 to 10, and the number of carbon atoms is 0 to 6, such as an amine group, a methylamino group, a dimethylamino group, a diethylamino group, and a dipentyl group. Amino group, etc.), alkoxy group (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and 1 to 12 carbon atoms) 8, for example, methoxy, ethoxy, butoxy, etc.), aryloxy (exemplified by preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 carbon atoms) ~12, such as phenoxy, 2-naphthyloxy, etc.), fluorenyl (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 1 to 12 carbon atoms) , for example, an ethyl fluorenyl group, a benzamidine group, a decyl group, a trimethyl ethane group, etc.), an alkoxy carbon group (for example, preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms) , particularly preferably a carbon number of 2 to 12, such as a methoxycarbonyl group or an ethoxycarbonyl group, or an aryloxycarbonyl group (exemplified by preferably having 7 to 20 carbon atoms and more preferably 7 to 16 carbon atoms). , particularly preferably having a carbon number of 7 to 10, such as a phenoxycarbonyl group, or a decyloxy group (exemplified by preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably a carbon atom). a number of 2 to 10, for example, an ethoxylated group, a benzhydryloxy group, or the like, and a guanamine group (for example, preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and a particularly excellent carbon atom) a number of 2 to 10, such as an acetamidoamine group, a benzhydrylamino group, etc.), an alkoxycarbonylamine group (for example, preferably 2 to 2 carbon atoms) 0, more preferably a carbon number of 2 to 16, a particularly preferred carbon number of 2 to 12, such as a methoxycarbonylamino group, or an aryloxycarbonylamino group (for example, preferably a carbon number of 7 to 20) More preferably, the number of carbon atoms is 7 to 16, the number of carbon atoms is 7 to 12, such as phenoxycarbonylamine, etc., and the sulfonylamino group (for example, preferably having 1 to 20 carbon atoms) It is a carbon number of 1 to 16, a particularly good carbon number of 1 to 12, such as a methanesulfonylamino group, a benzosulfonylamino group, etc., an alkylamine sulfonyl group and an arylamine sulfonyl group (for example Preferably, the number of carbon atoms is 0 to 20, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as an amine sulfonyl group, a methimsulfonyl group, a dimethylamine sulfonyl group, Phenylamine sulfonyl group, etc., an amine carbenyl group (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 1 to 12 carbon atoms, such as amine formazan) a group, a methylamine, a methylamine, a phenylamine, a phenylamine, a thiol group, etc., an alkylthio group (for example, preferably a carbon number of 1 to 20, more preferably a carbon number of 1 to 16) , particularly preferred is a carbon number of 1 to 12, such as methylthio, ethylthio, etc.), an arylthio group (for example, preferably 6 to 20 carbon atoms, more preferably carbon) The atomic number is 6 to 16, the particularly preferred carbon number is 6 to 12, for example, a phenylthio group, etc., and the alkylsulfonyl group is an arylsulfonyl group (for example, the number of carbon atoms is preferably from 1 to 20, more preferably, a carbon number of 1 to 16, a particularly preferred carbon number of 1 to 12, such as a methylsulfonyl group, a toluenesulfonyl group, etc., an alkylsulfinyl group and an arylsulfinyl group (exemplified by carbon) The number of atoms is 1 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as sulfinyl group, benzosulfinyl group, etc., and urea group (for example, preferably The number of carbon atoms is 1 to 20, more preferably, the number of carbon atoms is 1 to 16, the number of carbon atoms is 1 to 12, such as urea group, methylurea group, phenylureido group, etc., and guanidinium phosphate group (for example, Preferably, the number of carbon atoms is 1 to 20, more preferably, the number of carbon atoms is 1 to 16, and the number of carbon atoms is preferably 1 to 12, such as diethylphosphonium amide, phenylphosphonium amide, etc., hydroxyl group, hydrogen Sulfur group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfonyl group, carboxyl group, nitro group, hydroxamic acid group, sulfinyl group, fluorenyl group, imido group, heterocyclic ring The base (for example, preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and a hetero atom such as a nitrogen atom) , an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidinyl, morpholinyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, etc.) And a decyl group (for example, preferably, the number of carbon atoms is 3 to 40, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, for example, trimethyl decyl group, triphenyl decyl group, etc.) )Wait. These substituents may be further substituted. Further, in the case where the substituent is two or more, they may be the same or different. Also, in some cases, they may be connected to each other to form a loop.

The compound of the formula (4) is preferably a compound represented by the following formula (4-A).

In the formula, R ^{1 b} , R ^{2 b} , R ^{3 b} , R ^{4 b} , R ^{5 b} , R ^{6 b} , R ^{7 b} , R ^{8 b} , and R ^{9 b} each independently represent a hydrogen atom or a substituent.

R ^{1 b} , R ^{2 b} , R ^{3 b} , R ^{4 b} , R ^{5 b} , R ^{6 b} , R ^{7 b} , R ^{8 b} , and R ^{9 b} each independently represent a hydrogen atom or a substituent, and the substituent may be The aforementioned substituent T is applied. Further, such substituents may be further substituted by other substituents, or the substituents may be condensed to each other to form a ring structure.

R ^{1 b} , R ^{3 b} , R ^{4 b} , R ^{5 b} , R ^{6 b} , R ^{8 b} and R ^{9 b are} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted one. Amino group, alkoxy group, aryloxy group, hydroxyl group, halogen atom, preferably hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, halogen atom, more preferably hydrogen atom, carbon 1-12 alkane The base is particularly preferably a hydrogen atom or a methyl group, and is preferably a hydrogen atom.

R ^{2 b is} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably a hydrogen atom or a carbon number. 1 to 20 alkyl groups, 0 to 20 carbon atoms, 1 to 12 carbon atoms, 6 to 12 aryloxy groups, hydroxyl groups, more preferably 1 to 20 carbon atoms; Particularly preferred is an alkoxy group having 1 to 12 carbon atoms.

R ^{7 b is} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably a hydrogen atom or a carbon number. 1 to 20 alkyl groups, carbon number 0 to 20 amine groups, carbon number 1 to 12 alkoxy groups, carbon number 6 to 12 aryloxy groups, hydroxyl groups, more preferably hydrogen atoms, carbon number 1 to 20 alkyl groups The base (preferably having a carbon number of 1 to 12, preferably a carbon number of 1 to 8, more preferably a methyl group) is particularly preferably a methyl group or a hydrogen atom.

The compound of the formula (4) is preferably a compound represented by the following formula (4-B).

In the formula, R ^{1 0 b} represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group.

R ^{1 0 b} represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, and the substituent may be applied to the aforementioned substituent T. .

R ^{1 0 b is} preferably a substituted or unsubstituted alkyl group, preferably a substituted or unsubstituted alkyl group having 5 to 20 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 5 to 12 carbon atoms (for example) Such as n-hexyl, 2-ethylhexyl, n-octyl, n-fluorenyl, n-undecyl, benzyl, etc., particularly preferably a substituted or unsubstituted alkyl group having 6 to 12 carbons ( 2-ethylhexyl, n-octyl, n-fluorenyl, n-undecyl, benzyl).

The compound represented by the formula (4) can be synthesized by a known method described in JP-A-11-12219.

Specific examples of the compound represented by the general formula (4) are shown below, but the present invention is not limited by the following specific examples.

Further, one of the wavelength dispersion adjusting agents used in the second aspect of the present invention, that is, a compound containing a cyano group, is preferably one represented by the formula (5).

In the formula, Q ^{1 c} and Q ^{2 c} represent independent aromatic rings. X ^{1 c} and X ^{2 c} represent a hydrogen atom or a substituent, and at least one of them represents a cyano group, a carbonyl group, a sulfonyl group, or an aromatic hetero ring. The aromatic ring represented by Q ^{1 c} and Q ^{2 c} may be an aromatic hydrocarbon ring or an aromatic hetero ring. Further, they may be a single ring or may further form a condensed ring with other rings.

The aromatic hydrocarbon ring is preferably a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 30 carbon atoms (for example, a benzene ring or a naphthalene ring), and preferably has 6 to 20 carbon atoms. The aromatic hydrocarbon ring is more preferably an aromatic hydrocarbon ring having 6 to 12 carbon atoms. More preferably, it is a benzene ring.

The aromatic heterocyclic ring is preferably an aromatic heterocyclic ring containing a fluorine atom or a sulfur atom. Specific examples of the heterocyclic ring include thiophene, imidazole, pyrazole, pyridine, and pyridyl. 哒 Triazole, three , hydrazine, carbazole, hydrazine, thiazoline, thiazole, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline, hydrazine , naphthalene ingot, quinoxaline, quinazoline, porphyrin, acridine, acridine, phenanthroline, phenanthrene , tetrazole, benzimidazole, benzoxazole, benzothiazole, benzotriazole, tetralazide. The aromatic heterocyclic ring is preferably pyridine or three ,quinoline.

The aromatic ring represented by Q ^{1 c} and Q ^{2 c} is preferably an aromatic hydrocarbon ring, preferably a benzene ring. Q ^{1 c} and Q ^{2 c} may further contain a substituent, and a substituent T to be described later is preferred. The substituent T is, for example, an alkyl group (for example, preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably having 1 to 8 carbon atoms, such as methyl, ethyl or isopropyl groups). , a third butyl group, an n-octyl group, a n-decyl group, a n-hexadecyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, etc.), an alkenyl group (for example, preferably a carbon number of 2 to 20, more preferably a carbon atom number of 2 to 12, a particularly preferred carbon number of 2 to 8, such as a vinyl group, an allyl group, a 2-butenyl group, a 3-pentenyl group, etc., an alkynyl group (exemplified by a carbon atom) a number of 2 to 20, more preferably a carbon number of 2 to 12, a particularly preferred carbon number of 2 to 8, such as a propargyl group, a 3-pentynyl group, or the like, an aryl group (for example, preferably a carbon number of 6) ~30, more preferably a carbon number of 6 to 20, a particularly preferred carbon number of 6 to 12, such as a phenyl group, a p-tolyl group, a naphthyl group or the like, a substituted or unsubstituted amine group (for example, preferably The number of carbon atoms is 0 to 20, more preferably 0 to 10, and the number of carbon atoms is 0 to 6, such as an amine group, a methylamino group, a dimethylamino group, a diethylamino group, and a dipentyl group. Amino group, etc.), alkoxy group (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and 1 to 12 carbon atoms) 8, for example, methoxy, ethoxy, butoxy, etc.), aryloxy (exemplified by preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 carbon atoms) ~12, such as phenoxy, 2-naphthyloxy, etc.), fluorenyl (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 1 to 12 carbon atoms) , for example, an ethyl fluorenyl group, a benzamidine group, a decyl group, a trimethyl ethane group, etc.), an alkoxycarbonyl group (exemplified by preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms). Particularly preferred is a carbon number of 2 to 12, such as a methoxycarbonyl group or an ethoxycarbonyl group, and an aryloxycarbonyl group (exemplified by preferably having 7 to 20 carbon atoms and more preferably 7 to 16 carbon atoms). Particularly preferred is a carbon number of 7 to 10, such as a phenoxycarbonyl group, or a decyloxy group (exemplified by preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably having 2 to 16 carbon atoms). 2 to 10, for example, an oximeoxy group, a benzylideneoxy group, etc.), a guanamine group (for example, preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and a particularly good carbon number) 2 to 10, for example, an ethoxymethylamino group, a benzhydrylamino group, etc.), an alkoxycarbonylamine group (for example, preferably 2 to 2 carbon atoms) 0, more preferably a carbon number of 2 to 16, a particularly preferred carbon number of 2 to 12, such as a methoxycarbonylamino group, or an aryloxycarbonylamino group (for example, preferably a carbon number of 7 to 20) More preferably, the number of carbon atoms is 7 to 16, the number of carbon atoms is 7 to 12, such as phenoxycarbonylamine, etc., and the sulfonylamino group (for example, preferably having 1 to 20 carbon atoms) It is a carbon number of 1 to 16, a particularly good carbon number of 1 to 12, such as a methanesulfonylamino group, a benzosulfonylamino group, etc., an alkylamine sulfonyl group and an arylamine sulfonyl group (for example Preferably, the number of carbon atoms is 0 to 20, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as an amine sulfonyl group, a methimsulfonyl group, a dimethylamine sulfonyl group, Phenylamine sulfonyl group, etc., an amine carbenyl group (exemplified by preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 1 to 12 carbon atoms, such as amine formazan) a group, a methylamine, a methylamine, a phenylamine, a phenylamine, a thiol group, etc., an alkylthio group (for example, preferably a carbon number of 1 to 20, more preferably a carbon number of 1 to 16) , particularly preferred is a carbon number of 1 to 12, such as methylthio, ethylthio, etc.), an arylthio group (for example, preferably 6 to 20 carbon atoms, more preferably carbon) The atomic number is 6 to 16, the particularly preferred carbon number is 6 to 12, for example, a phenylthio group, etc., and the alkylsulfonyl group is an arylsulfonyl group (for example, the number of carbon atoms is preferably from 1 to 20, more preferably, a carbon number of 1 to 16, a particularly preferred carbon number of 1 to 12, such as a methylsulfonyl group, a toluenesulfonyl group, etc., an alkylsulfinyl group and an arylsulfinyl group (exemplified by carbon) The number of atoms is 1 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as sulfinyl group, benzosulfinyl group, etc., and urea group (for example, preferably The number of carbon atoms is 1 to 20, more preferably, the number of carbon atoms is 1 to 16, the number of carbon atoms is 1 to 12, such as urea group, methylurea group, phenylureido group, etc., and guanidinium phosphate group (for example, Preferably, the number of carbon atoms is 1 to 20, more preferably, the number of carbon atoms is 1 to 16, and the number of carbon atoms is preferably 1 to 12, such as diethylphosphonium amide, phenylphosphonium amide, etc., hydroxyl group, hydrogen Sulfur group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfonyl group, carboxyl group, nitro group, hydroxamic acid group, sulfinyl group, fluorenyl group, imido group, heterocyclic ring The base (for example, preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and a hetero atom such as a nitrogen atom) , an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidinyl, morpholinyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, etc.) And a decyl group (for example, preferably, the number of carbon atoms is 3 to 40, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, for example, trimethyl decyl group, triphenyl decyl group, etc.) )Wait. These substituents may be further substituted. Further, in the case where the substituent is two or more, they may be the same or different. Also, in some cases, they may be connected to each other to form a loop.

X ^{1 c} and X ^{2 c} represent a hydrogen atom or a substituent, and at least one of them represents a cyano group, a carbonyl group, a sulfonyl group, or an aromatic hetero ring. The substituents represented by X ^{1 c} and X ^{2 c} are applicable to the aforementioned substituent T. Further, the substituents represented by X ^{1 c} and X ^{2 c} may be further substituted by other substituents, and each of X ^{1 c} and X ^{2 c} may be condensed to form a ring structure.

X ^{1 c} and X ^{2 c are} preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group, an aromatic hetero ring, more preferably a cyano group, a carbonyl group, a sulfonyl group or an aromatic group. The heterocyclic ring is more preferably a cyano group, a carbonyl group, particularly preferably a cyano group or an alkoxycarbonyl group (-C(=O)OR (R: an alkyl group having 1 to 20 carbon atoms and a carbon number of 6 to 12) Base and these combinations))).

The compound of the formula (5) is preferably a compound represented by the following formula (5-A).

In the formula, R ^{1 c} , R ^{2 c} , R ^{3 c} , R ^{4 c} , R ^{5 c} , R ^{6 c} , R ^{7 c} , R ^{8 c} , R ^{9 c} and R ^{1 0 c} represent independent hydrogen atoms. Or a substituent. X ^{1 c} and X ^{2 c} are synonymous with those of the formula (5), and the preferred ranges are also the same.

R ^{1 c} , R ^{2 c} , R ^{3 c} , R ^{4 c} , R ^{5 c} , R ^{6 c} , R ^{7 c} , R ^{8 c} , R ^{9 c} and R ^{1 0 c} represent independent hydrogen atoms or substituents. The substituent T can be applied to the substituent. Further, such substituents may be further substituted by other substituents, and the substituents may be condensed to each other to form a ring structure.

R ^{1 c} , R ^{2 c} , R ^{3 c} , R ^{4 c} , _R ^{5 c} , R ^{6 c} , R ^{7 c} , R ^{8 c} , R ^{9 c} and R ^{1 0 c are} preferably a hydrogen atom, an alkyl group or an alkene. Alkyl, alkynyl, aryl, substituted or unsubstituted amino, alkoxy, aryloxy, hydroxy, halogen atom, preferably hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, halogen The atom is more preferably a hydrogen atom or a carbon 12 to 12 alkyl group, particularly preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

R ^{3 c} and R ^{8 c are} preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, a halogen atom, preferably hydrogen. Atom, an alkyl group having 1 to 20 carbon atoms, an amine group having 0 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a 6 to 12 aryloxy group having a carbon number, a hydroxyl group, more preferably a hydrogen atom, or a carbon number of 1. The alkyl group of ~12 and the alkoxy group of 1 to 12 carbon atoms are particularly preferably a hydrogen atom.

The compound of the formula (5) is preferably a compound represented by the following formula (5-B).

In the formula, R ^{3 c} and R ^{8 c} are the same as those of the formula (5-A), and the preferred range is also the same. X ^{3 c} represents a hydrogen atom or a substituent

X ^{3 c} represents a hydrogen atom or a substituent, and the substituent T can be applied to the substituent, and, where possible, it may be further substituted with a substituent. X ^{3 c is} preferably a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a carbonyl group, a sulfonyl group, an aromatic heterocyclic ring, more preferably a cyano group, a carbonyl group, a sulfonyl group, an aromatic heterocyclic ring, or the like. Preferred is a cyano group, a carbonyl group, particularly preferably a cyano group, an alkoxycarbonyl group (-C(=O)OR (R: an aryl group having 1 to 20 carbon atoms, 6 to 12 carbon atoms, and the like) Combiner).

The compound of the formula (5) is more preferably a compound represented by the formula (5-C).

In the formula, R ^{3 c} and R ^{8 c} are the same as those of the formula (5-A), and the preferred range is also the same. R ^{2 1 c} represents an alkyl group having 1 to 20 carbon atoms.

R ^{2 1 c is} preferably an alkyl group having 2 to 12 carbon atoms, more preferably an alkyl group having 4 to 12 carbon atoms, more preferably carbon, in the case where both of R ^{3 c} and R ^{8 c} are hydrogen. The alkyl group having 6 to 12 atoms, particularly preferably n-octyl, trioctyl, 2-ethylhexyl, n-fluorenyl or n-dodecyl, is preferably 2-ethylhexyl.

R ^{2 1 c is} preferably a case where R ^{3 c} and R ^{8 c} are other than hydrogen, and the compound represented by the formula (5-C) has a molecular weight of 300 or more and an alkane having a carbon number of 20 or less. The base is good.

The compound represented by the formula (5) can be synthesized according to the method described in Journal of American Chemical Society, Vol. 63, p. 3452 (1941).

Hereinafter, specific examples of the compound represented by the formula (5) will be exemplified, but the present invention is not limited by the following specific examples.

"Manufacturing of bismuth cellulose film"

It is preferred to produce a deuterated cellulose film by a solvent casting method. The solvent casting method uses a solution (slurry) in which deuterated cellulose is dissolved in an organic solvent to produce a film. The organic solvent comprises a solvent selected from the group consisting of an ether having 3 to 12 carbon atoms, a ketone having 3 to 12 carbon atoms, an ester having 3 to 12 carbon atoms, and a halogenated hydrocarbon having 1 to 6 carbon atoms. good. The ethers, ketones and esters may have a cyclic structure. Any of the functional groups of the ether, the ketone, and the ester (that is, -O-, -CO-, and -COO-) may be used as an organic solvent even if it contains two or more compounds. The organic solvent may contain other functional groups such as an alcoholic hydroxyl group. In the case of an organic solvent containing two or more functional groups, the number of carbon atoms of the solvent having any functional group is preferably in the range of the above preferred carbon number.

Examples of the ether having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, and 1,3-dioxolane. , tetrahydrofuran, anisole and phenylethyl ether. Examples of the ketone having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone, and methylcyclohexanone. Examples of the ester having 3 to 12 carbon atoms include ethyl formate, propyl formate, amylformate, methyl acetate, ethyl acetate, and pentyl acetate. Examples of the organic solvent having two or more functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol, and 2-butoxyethanol. The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and 1 is most preferred. The halogen of the halogenated hydrocarbon is preferably chlorine. The hydrogen atom of the halogenated hydrocarbon is preferably 25 to 75 mol% in terms of halogen substitution, preferably 30 to 70 mol%, more preferably 35 to 65 mol%, and most preferably 40 to 60 mol%. Dichloromethane is a representative halogenated hydrocarbon.

The deuterated cellulose solution can be prepared in a conventional manner. The general method means treatment with a temperature of 0 ° C or higher (normal temperature or high temperature). The preparation of the solution can be carried out by using a method and apparatus for preparing a paste in a general solution casting method. Further, in the case of the general method, it is preferred to use a halogenated hydrocarbon (particularly dichloromethane) as the organic solvent.

The amount of deuterated cellulose is adjusted to be 10 to 40% by mass in the resulting solution. The amount of deuterated cellulose is preferably from 10 to 30% by mass. Any of the additives described below may be added to the organic solvent (main solvent). The solution can be prepared by stirring the cellulose and the organic solvent at room temperature (0 to 40 ° C). The high concentration solution can be stirred under pressure and heating. Specifically, the deuterated cellulose and the organic solvent are placed in a pressurized container and sealed, and the mixture is stirred under pressure at a temperature above the normal temperature of the solvent, and the solvent is heated while being in a temperature at a non-boiling range. The heating temperature is usually 40 ° C or higher, preferably 60 to 200 ° C, more preferably 80 to 110 ° C.

Each component can be filled into the container because it is coarsely mixed in advance. Moreover, it can be sequentially put into the container. It is necessary to stir the container to form a system. It may be injected with an inert gas such as nitrogen to pressurize the container. Further, the vapor pressure of the solvent can be increased by the use of heat. Alternatively, the components may be added under pressure after the container is sealed. It is preferred to heat from the outside of the container during heating. For example, a jacket type of heating device can be used. Further, the liquid can be circulated to heat the entire container by providing a tube-shaped heater on the outside of the container. It is preferable to provide a stirring blade inside the container and use it for stirring. It is preferred that the agitating wing system reaches a length near the wall of the container. The end of the agitating blade is preferably a scraper blade in order to renew the liquid film of the container wall. A gauge such as a pressure gauge or a thermometer may be provided in the container. The ingredients are dissolved in a solvent in a container. The prepared dope is taken out from the cooled container, or taken out, and cooled by a heat exchanger or the like.

The solution can also be prepared by a cooling dissolution method. The cooling and dissolving method can dissolve the deuterated cellulose even in an organic solvent which is difficult to dissolve by a general dissolution method. Further, the solvent for deuterated cellulose can be dissolved by a general dissolution method, and even if it is cooled by a dissolution method, a uniform solution can be obtained quickly. The cooling dissolution method is initially carried out by slowly adding the deuterated cellulose to the organic solvent at room temperature while stirring. The amount of deuterated cellulose is preferably adjusted to be 10 to 40% by mass in the mixture. The amount of deuterated cellulose is preferably from 10 to 30% by mass. Further, any additives described later may be added to the mixture.

Next, the mixture is cooled at -100 to -10 ° C (exemplified by preferably -80 to -10 ° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). Cooling can be, for example, dry ice. It is carried out in a methanol bath (-75 ° C) or a cooled diethylene glycol solution (-30 to -20 ° C). A mixture of deuterated cellulose and an organic solvent can be solidified by cooling.

The cooling rate is preferably 4 ° C / min or more, more preferably 8 ° C / min or more, and most preferably 12 ° C / min or more. The faster the cooling rate, the better, but 10,000 ° C / sec is the theoretical upper limit, 1,000 ° C / sec is the technical upper limit, and 100 ° C / sec is the practical upper limit. Further, the cooling rate is the difference between the temperature at which cooling starts and the final cooling temperature, divided by the value from the start of cooling to the time when the final cooling temperature is reached.

Further, it is heated at 0 to 200 ° C (exemplified by preferably 0 to 150 ° C, more preferably 0 to 120 ° C, optimum 0 to 50 ° C), and the deuterated fiber is dissolved in an organic solvent. Prime. The temperature rise can be placed at room temperature and can be warmed in a warm bath.

The heating rate is preferably 4 ° C / min or more, more preferably 8 ° C / min or more, and 12 ° C / min or more is optimal. The heating rate is as fast as possible, but 10,000 ° C / sec is the theoretical upper limit, 1,000 ° C / sec is the technical upper limit, and 100 ° C / sec is the practical upper limit. Further, the heating rate is the difference between the temperature at which heating is started and the final heating temperature, divided by the value from the start of heating to the time when the final heating temperature is reached.

As described above, a homogeneous solution can be obtained. Further, in the case where the dissolution system is insufficient, the operation of cooling and heating can be repeated. Whether or not it is sufficiently dissolved can be judged by visually observing the appearance of the solution.

In the cooling and dissolving method, it is desirable to use a closed container in order to prevent moisture from entering due to condensation during cooling. Further, when the cooling and heating operation is performed at the time of cooling and the pressure is reduced at the time of heating, the dissolution time can be shortened. In order to carry out pressurization and pressure reduction, it is desirable to use a pressure resistant container.

In addition, deuterated cellulose (degree of vinegar: 60.9%, viscosity average degree of polymerization: 299) is a 20% by mass solution dissolved in methyl acetate by a cooling dissolution method, by differential scanning calorimeter (DSC) At the time of measurement, a pseudo phase transition point of a sol state and a gel state existed at approximately 33 ° C, and a uniform gel state was formed below this temperature. Therefore, it is necessary that the solution be maintained at a temperature above the pseudo phase transition temperature, preferably at a temperature of about 10 ° C at the gel phase transition temperature. However, the pseudo phase transfer temperature differs depending on the degree of hydration of the deuterated cellulose, the average degree of polymerization of the viscosity, the concentration of the solution, or the organic solvent used.

A deuterated cellulose film can be produced by a solvent casting method according to the prepared deuterated cellulose solution (glue).

The glue is cast on a drum or conveyor belt and the solvent is evaporated to form a film. The pre-casting paste is preferably adjusted to have a solid content of 18 to 35%. The surface of the drum or conveyor belt is preferably in the form of a mirror finish. The method of casting and drying the solution casting method is described in U.S. Patent No. 2,313,310, the same as No. 2,367,603, No. 2,492,078, No. 2,492,977, No. 2,492,978, No. 2,607,704, No. 2,739,069, No. 2,739,070, and British Patent. Japanese Patent Publication No. 640731, No. 736,892, Japanese Patent Publication No. Sho 45-4554, No. 49-5614, JP-A-60-176834, No. 60-203430, and No. 62-115035.

It is preferred that the glue be cast on a drum or a conveyor belt having a surface temperature of 10 ° C or less. It is preferred to dry from a wind that is cast for 2 seconds or longer. The obtained film is peeled off from a drum or a conveyor belt, and then dried by a high-temperature wind which is successively changed in temperature from 100 to 160 ° C to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, the time from casting to stripping can be shortened. In order to carry out the method, it is necessary to gel the gel at the surface temperature of the drum or conveyor belt which is delayed.

In order to improve the mechanical properties in the deuterated cellulose film, the following plasticizers can be used. A phosphate or a carboxylate can be used as the plasticizer. Examples of phosphates include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Carboxylic esters are represented by phthalates and citrates. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP). , diphenyl phthalate (DPP) and diethylhexyl phthalate (DEHP). Examples of the citric acid esters include triethyl O-ethinyl citrate (OACTE) and tributyl O-ethenyl citrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methyl decyl ricinolate, dibutyl sebacate, and various trimellitic acid esters. Preferably, a benzoate plasticizer (DMP, DEP, DBP, DOP, DPP, DEHP) is used. Among them, DEP and DPP are particularly good.

The amount of the plasticizer added is preferably from 0.1 to 25% by mass, more preferably from 1 to 20% by mass, most preferably from 3 to 15% by mass.

A deterioration preventing agent (for example, an antioxidant, a peroxide decomposing agent, a radical inhibitor, a metal inerting agent, an acid trapping agent, or an amine) may be added to the deuterated cellulose film. The deterioration prevention agent is described in each of the publications of JP-A No. 3-199201, No. 5-1907073, No. 5-194749, No. 5-271471, and No. 6-207054. The amount of the deterioration preventing agent to be added is preferably 0.01 to 1% by mass, more preferably 0.01 to 0.2% by mass, based on the preparation solution (slurry). When the amount added is in the above range, the effect of the deterioration preventing agent can be obtained, that is, the bleeding of the surface of the film is not observed. Examples of the particularly preferable deterioration preventing agent include butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

"Extension treatment of bismuth cellulose film"

The deuterated cellulose film can be adjusted for hysteresis by elongation processing. The stretching ratio is preferably from 3 to 100%.

The stretching method is not particularly limited, and a well-known method can be used. From the viewpoint of in-plane uniformity, it is particularly preferable to use a tenter to extend. The deuterated cellulose film used in the second aspect of the present invention is preferably at least 100 cm in width and preferably has a variation in Re value of ±5 nm. ±3 nm is more preferred. Further, the deviation of the Rth value is preferably ±10 nm, more preferably ±5 nm. Further, the variation of the Re value in the longitudinal direction and the variation in the Rth value is preferably in the range of the deviation in the width direction.

Further, the stretching treatment may be carried out on the way of the film forming step, or the raw material film taken up by the film forming may be subjected to elongation treatment. In the former case, the stretching may be carried out in a state containing the residual solvent amount, or it may be preferably extended when the residual solvent amount is 2 to 30%. At this time, the film is stretched in the direction orthogonal to the longitudinal direction while being conveyed in the longitudinal direction, and the slow axis of the film is preferably orthogonal to the longitudinal direction of the film.

The extension temperature can be selected according to the amount of residual solvent at the time of stretching and the film thickness. In the case of extending in a state containing a residual solvent, it is preferred to dry it after stretching. The drying method can be carried out in accordance with the method described in the film formation of the above film.

The thickness of the extended deuterated cellulose film is preferably 110 μm or less, preferably 40 to 110 μm, preferably 60 to 110 μm and 80 to 110 μm.

"Surface treatment of bismuth cellulose film"

In the case where the transparent film composed of the deuterated cellulose film is used as a transparent protective film of a polarizing plate, the surface treated deuterated cellulose film is preferred. The surface treatment is subjected to corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment or ultraviolet irradiation treatment. It is particularly preferable to carry out an acid treatment or an alkali treatment, that is, saponification treatment of deuterated cellulose.

a rod-shaped compound having a linear structure having at least two aromatic rings extending as described above, a deuterated cellulose film satisfying a desired retardation value Re, Rth, and Re/Rth ratio and having a film thickness of 40 μm to 110 μm In addition, it satisfies the optical characteristics of the above transparent film, and can be used as a part of the optical compensation film for various liquid crystal display devices.

[optical anisotropic layer]

The optical compensation film according to the second aspect of the present invention has at least one optically anisotropic layer formed of a liquid crystalline compound. The optically anisotropic layer may be formed directly on the surface of the transparent film, form an alignment film on the transparent film, or may be formed on the alignment film. Further, the liquid crystal compound layer formed on the other substrate may be transferred onto a transparent film by using an adhesive, an adhesive or the like to prepare an optical compensation film according to the second aspect of the present invention.

The liquid crystal compound used for the formation of the optically anisotropic layer is, for example, a rod-like liquid crystal compound and a discotic liquid crystal compound (hereinafter, the discotic liquid crystal compound is also referred to as a "disc liquid crystal compound"). The situation). The rod-like liquid crystal compound and the discotic liquid crystal compound may be a polymer liquid crystal or a low molecular liquid crystal. Further, the compound contained in the final optically anisotropic layer has not been shown to have liquid crystallinity. For example, in the case where a low molecular liquid crystalline compound is used in the production of an optically anisotropic layer, optical anisotropy is formed. In the course of the layer, the compound may also be in a form which does not exhibit crosslinked liquid crystallinity.

(rod-like liquid crystalline compound)

Examples of the rod-like liquid crystalline compound which can be used in the second aspect of the present invention preferably include a methylimine, an azogen group, a cyanobiphenyl group, a cyanophenyl ester, and a benzoic acid ester. Benzyl carboxylic acid phenyl esters, cyanophenyl cyclohexanes, cyano substituted phenyl pyrimidines, alkoxy substituted phenyl pyrimidines, phenyl dioxanes, diphenyl acetylenes And alkenylcyclohexylbenzonitriles. Further, a metal complex may be contained in the rod-like liquid crystalline compound. Further, as the rod-like liquid crystal compound, a liquid crystal polymer contained in a repeating unit can also be used. In other words, the rod-like liquid crystalline compound may also be combined with the (liquid crystal) polymer.

The rod-like liquid crystal compound is described in the 24th issue of the Journal of Chemical Industry, Liquid Crystal Chemistry (1994), Chapter 4, Chapter 7 and Chapter 11 of the Japanese Chemical Society, and the Handbook of Liquid Crystal Devices, the 142th Committee of the Japan Society for the Promotion of Science. Chapter 3 of the series.

The birefringence of the rod-like liquid crystal compound used in the second aspect of the present invention is preferably in the range of 0.001 to 0.7.

The rod-like liquid crystalline compound is preferably a polymerizable group in order to fix its alignment state. The polymerizable group is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.

(disc liquid crystal compound)

The dish-like liquid crystal compound includes a research report by C. Destrade et al., a benzene derivative described in Mol. Cryst. 71, 111 (1981), a research report by C. Destrade, and the like, and a volume of Mol. Cryst. , 141 pages (1985), Physics lett, A, 78, 82 (1990), trioxo derivatives, B. Kohne et al., Angew. Chem. 96, 70 ( Cyclohexane derivative described in 1984) and JMLehn et al., J. Chem. Commun., 1794 (1985), J. Zhang et al., J. Am. Chem. Soc. The crown of the crown or the phenylacetylene macrocycle described in Vol. 116, 2655 (1994).

In the above-mentioned discotic liquid crystalline compound, a linear alkyl group, an alkoxy group or a substituted benzoquinoneoxy group is a structure in which a side chain of a mother nucleus is substituted in a radial direction with respect to a core of a molecular center, and a compound exhibiting liquid crystallinity . It is preferred that the molecular or molecular assembly system has a rotational symmetry and a compound capable of imparting a fixed alignment.

In the above case, the case where the optically anisotropic layer is formed of a liquid crystalline compound or the compound which is also included in the final optically anisotropic layer does not exhibit liquid crystallinity. For example, a low-molecular dish-like liquid crystalline compound has a group reactive with heat or light, and reacts, polymerizes, or crosslinks the group by heat or light, and is subjected to high molecular weight to form an optical anisotropic layer. The compound contained in the optically anisotropic layer in the case of the like may also have lost liquid crystallinity. A preferred example of the discotic liquid crystal compound is described in JP-A-8-50206. Further, the polymerization of the discotic liquid crystal compound is described in JP-A-8-27284.

In order to fix by arranging a discotic liquid crystalline compound, it is necessary to form a polymerizable group bonding system as a substituent on the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly bonded to the disk-shaped core, it becomes difficult to maintain the alignment state of the polymerization reaction. For this purpose, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula (III).

In the formula (III)D(-L-Q) _n wherein D is a discotic core, L is a divalent linking group, Q is a polymerizable group, and n is an integer of 4 to 12.

Examples of the disc-shaped core (D) are as follows. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

In the formula (III), the divalent linking group (L) is selected from the group consisting of an alkyl group, an alkenyl group, an extended aryl group, -CO-, -NH-, -O-, -S-, and the like. The divalent linking group constituting the group is preferred. The divalent linking group (L) is a divalent linking group comprising at least two divalent groups selected from the group consisting of alkylene, aryl, -CO-, -NH-, -O- and S- The base is preferred. The divalent linking group (L) is preferably a divalent linking group which combines at least two divalent groups selected from the group consisting of an alkylene group, an extended aryl group, and -CO- and O-. The alkyl group of the above alkyl group is preferably from 1 to 12. The number of carbon atoms of the above alkenyl group is preferably from 2 to 12. The number of carbon atoms of the above aryl group is preferably from 6 to 10.

An example of the divalent linking group (L) is as follows. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (Q). AL means an alkyl group or an alkenyl group, and an AR type means an aryl group. Further, the alkylene group, the alkenyl group and the extended aryl group may have a substituent (for example, an alkyl group).

L1:-AL-CO-O-AL- L2:-AL-CO-O-AL-O- L3:-AL-CO-O-AL-O-AL- L4:-AL-CO-O-AL- O-CO- L5:-CO-AR-O-AL- L6:-CO-AR-O-AL-O- L7:-CO-AR-O-AL-O-CO- L8:-CO-NH- AL- L9:-NH-AL-O- L10:-NH-AL-O-CO- L11:-O-AL- L12:-O-AL-O- L13:-O-AL-O-CO- L14 :-O-AL-O-CO-NH-AL- L15:-O-AL-S-AL- L16:-O-CO-AR-O-AL-CO- L17:-O-CO-AR-O -AL-O-CO- L18:-O-CO-AR-O-AL-O-AL-O-CO- L19:-O-CO-AR-O-AL-O-AL-O-AL-O -CO- L20:-S-AL- L21:-S-AL-O- L22:-S-AL-O-CO- L23:-S-AL-S-AL- L24:-S-AR-AL-

The polymerizable group (Q) of the formula (III) is determined depending on the type of the polymerization reaction. The polymerizable group (Q) is preferably an unsaturated polymerizable group or an epoxy group, and an unsaturated polymerizable group is preferred, and an ethylenically unsaturated polymerizable group is most preferred.

In the formula (III), n is an integer of 4 to 12. The specific number is determined according to the type of the disc-shaped core (D). In addition, the combination of the plural L and Q may be different and the same.

According to a second aspect of the invention, in the optically anisotropic layer, the molecular structure of the rod-shaped compound or the discotic compound is fixed to an alignment state. The orientation average direction of the molecular symmetry axis of the liquid crystal compound at the side of the transparent film side is about 0 degrees or substantially 90 degrees with the in-plane slow axis of the transparent film. Further, in the present specification, "approximately 0 or 90 degrees" is preferably an angle of 0 ° ± 5 ° or 90 ° ± 5 °, preferably 42 to 48 °, preferably 43 to 47 °. The average direction of the molecular symmetry axis of the liquid crystalline compound in the optically anisotropic layer is preferably 43 to 47 with respect to the longitudinal direction of the transparent film (that is, the direction of the phase axis of the transparent film).

The orientation average direction of the molecular symmetry axis of the liquid crystal compound can be generally adjusted by selecting a material of a liquid crystal compound or an alignment film or by selecting a rubbing treatment method. In the second aspect of the present invention, for example, when an alignment film for forming an optically anisotropic layer is formed by a rubbing treatment, the rubbing treatment can be performed in a direction of 45° with respect to the retardation axis of the transparent film. The molecular symmetry axis of the compound, at least the alignment average direction in the interface of the transparent film, forms an optically anisotropic layer that is 45° to the slow axis of the transparent film. For example, the optical compensation film according to the second aspect of the present invention can be continuously produced by using a long transparent film in which the slow phase axis is parallel to the longitudinal direction. Specifically, a coating liquid for forming an alignment film is continuously applied onto the surface of the long transparent film to form a film, and then the surface of the film is continuously rubbed in a direction of 45° in the longitudinal direction to prepare an alignment film, followed by preparation of an alignment film, followed by The coating liquid for forming an optically anisotropic layer containing a liquid crystal compound is continuously applied to the prepared alignment film, and the molecules of the liquid crystal compound are aligned, and the optically anisotropic layer is formed by being fixed in this state, thereby continuously A long optical compensation film is produced. The optical compensation film produced in a long strip shape is cut into a desired shape before being assembled into the liquid crystal display device.

Further, the orientation average direction of the molecular symmetry axis of the surface side (air side) of the liquid crystal compound, and the alignment average direction of the molecular symmetry axis of the liquid crystal compound on the air interface side are slightly 0° with respect to the slow phase axis of the transparent film. Or 90 ° is better, 42 ~ 48 ° is better, 43 ~ 47 ° is better. The orientation average direction of the molecular symmetry axis of the liquid crystal compound on the air interface side can be generally adjusted by selecting the type of the additive to be used together with the liquid crystal compound or the liquid crystal compound. Examples of the additive to be used together with the liquid crystalline compound include a plasticizer, a surfactant, a polymerizable monomer, and a polymer. The degree of change in the alignment direction of the molecular symmetry axis can also be adjusted in the same manner as described above by appropriately selecting the liquid crystal compound and the additive. In particular, it is preferable that the surfactant is coherent with the surface tension control of the above coating liquid.

The plasticizer, the surfactant, and the polymerizable monomer to be used together with the liquid crystal compound preferably have a compatibility with the liquid crystal compound, impart a change in the tilt angle of the liquid crystal compound, or do not interfere with the alignment. A polymerizable monomer (for example, a compound having a vinyl group, a vinyloxy group, a propylene group, and a methacryl group) is preferred. The amount of the compound to be added is preferably in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass based on the liquid crystal compound. Further, when a monomer having a polymerizable reactive functional group of 4 or more is used in combination, adhesion between the alignment film and the optically anisotropic layer can be improved.

When a discotic liquid crystalline compound which is a liquid crystal compound is used, it is preferred to use a polymer which has a certain degree of compatibility with a discotic liquid crystalline compound and which can impart a change in the tilt angle to the discotic liquid crystalline compound.

An example of the polymer is, for example, a cellulose ester. Preferable examples of the cellulose ester include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. The amount of the polymer to be added is preferably in the range of 0.1 to 10% by mass, preferably 0.1 to 8% by mass, based on the disk-like liquid crystal compound. The range of 0.1 to 5 mass% is more preferable.

The dish-like liquid crystal phase-solid phase transfer temperature of the dish-like liquid crystal compound is preferably 70 to 300 ° C and preferably 70 to 170 ° C.

In the second aspect of the invention, it is preferable that the optically anisotropic layer has at least in-plane optical anisotropy. The optical characteristics of the optically anisotropic layer are determined according to the optical characteristics or mode of the liquid crystal cell forming the optical compensation target. In the case of using a TN mode liquid crystal display device, it is preferable that the in-plane hysteresis value Re of the optically anisotropic layer is 3 to 300 nm, preferably 5 to 200 nm, and more preferably 10 to 100 nm. The hysteresis value Rth in the thickness direction of the optically anisotropic layer is preferably from 20 to 400 nm, and preferably from 50 to 200 nm. Further, the thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

[Alignment film]

In the optical compensation film according to the second aspect of the present invention, an alignment film may be provided between the transparent film and the optically anisotropic layer. Further, the optically anisotropic layer may be transferred onto the transparent film only after the alignment film is formed and the optically anisotropic layer is formed on the alignment film.

In the second aspect of the present invention, the alignment film is preferably a layer composed of a crosslinked polymer. The polymer used in the alignment film may be either a polymer which is self-crosslinkable or a polymer which is crosslinked by a crosslinking agent. The alignment film may be formed by reacting a polymer having a functional group or a polymer into a functional group by light, heat or pH, or the like, or by reacting a polymer; or using a highly reactive compound The crosslinking agent is formed by introducing a bonding group derived from a crosslinking agent between the polymers and crosslinking the polymer.

The alignment film composed of the crosslinked polymer can be generally formed by applying a coating liquid containing the above polymer or a mixture of a polymer and a crosslinking agent onto a support, followed by heating or the like.

In the rubbing step to be described later, in order to suppress dust generation of the alignment film, it is preferred to increase the degree of crosslinking. The difference (Ma/Mb) of the amount (Ma) of the crosslinking agent remaining after crosslinking is subtracted from 1 by the amount (Mb) of the crosslinking agent added to the above coating liquid (1) (Ma/Mb)) When the degree of crosslinking is defined, the degree of crosslinking is preferably 50% to 100%, preferably 65% to 100%, and most preferably 75% to 100%.

In the second aspect of the invention, the polymer used in the alignment film may be any of a polymer which can be self-crosslinked or a polymer which is crosslinked by a crosslinking agent. It is of course also possible to use polymers having both functions. Examples of the above polymer include polymethyl methacrylate, acrylic acid/methacrylic acid copolymer, styrene/methylene iodide copolymer, polyvinyl alcohol, and modified polyvinyl alcohol, poly(N). -Hydroxymethyl acrylamide, styrene/vinyl toluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimine, vinyl acetate/chlorine A compound such as an ethylene copolymer, an ethylene/vinyl acetate copolymer, carboxymethylcellulose, gelatin, polyethylene, a polymer such as polypropylene or polycarbonate, or a decane coupling agent. Examples of preferred polymers include water-soluble polymers such as poly(N-methylol acrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol, and gelatin, Polyvinyl alcohol and modified polyvinyl alcohol are preferred, and polyvinyl alcohol and modified polyvinyl alcohol are particularly preferred.

Among the above polymers, polyvinyl alcohol or modified polyvinyl alcohol is preferred.

The polyvinyl alcohol is, for example, a saponification degree of 70 to 100%, and is preferably a saponification degree of 80 to 100%, and a saponification degree of 82 to 98%. The degree of polymerization is preferably in the range of 100 to 3,000.

The modified polyvinyl alcohol may, for example, be a copolymerized reformer (modified base, for example, introduced COONa, Si(OX) ₃ , N(CH ₃ ) ₃ .Cl, C ₉ H _{1 9} COO, SO ₃ Na, C _{1 2} H _{2 5} or the like, which is modified by chain shift (modified base, for example, COONa, SH, SC _{1 2} H _{2 5} or the like), and polymerized by block polymerization (modified base, for example A modified product of polyvinyl alcohol such as COOH, CONH ₂ , COOR, C ₆ H ₅ or the like is introduced. The degree of polymerization is preferably in the range of 100 to 3,000. Among these, an unmodified or modified polyvinyl alcohol having a saponification degree of 80 to 100% is preferred, and a saponification degree of 85 to 95% is preferably an unmodified alkylthio-modified polyvinyl alcohol.

The modified polyvinyl alcohol used in the alignment film is preferably a reaction product of a compound represented by the following formula (6) and polyvinyl alcohol.

In the formula, R ^{1 d} represents an unsubstituted alkyl group, or an acryl fluorenyl group, a methacryl fluorenyl group or an alkyl group substituted with an epoxy group, and the W series is a halogen atom, an alkyl group or an alkoxy group, X ^{1 d} represents a necessary atomic group for forming an active ester, an acid anhydride or a hydrazine halide, and I represents 0 or 1, and n represents an integer of 0 to 4.

Further, the modified polyvinyl alcohol used in the alignment film may be a reaction product of a compound represented by the following formula (7) and polyvinyl alcohol.

In the formula, X ^{2 d} represents a necessary atomic group for forming an active ester, an acid anhydride or a hydrazine halide, and m represents an integer of 2 to 24.

The polyvinyl alcohol used for the reaction with the compound represented by the above formula (6) and the formula (7) may, for example, be the above-mentioned unmodified polyvinyl alcohol and the above-mentioned copolymerized modifier. That is, a modified product of polyvinyl alcohol such as a person who has been modified by chain movement or a reformer that has been polymerized by a block polymerization. A preferred example of the above-described specific modified polyvinyl alcohol is described in detail in Japanese Laid-Open Patent Publication No. Hei 8-338913.

When a hydrophilic polymer such as polyvinyl alcohol is used as the alignment film, the moisture content is preferably controlled from the viewpoint of hard film degree, preferably 0.4% to 2.5%, more preferably 0.6% to 1.6%. The water content can be measured by a commercially available Karl Fischer method moisture rate meter.

Further, it is preferred that the alignment film is a film thickness of 10 μm or less.

[Polarizer]

In the second aspect of the present invention, a polarizing plate comprising a polarizing film and one of the polarizing films may be used. For example, a polarizing film composed of a polyvinyl alcohol film or the like can be used for dyeing and stretching in iodine, and the polarizing plate obtained by laminating the protective film on both sides thereof. The polarizing plate is disposed outside the liquid crystal cell. It is preferable that one of the polarizing film and the polarizing film is formed by the polarizing film and the polarizing film, and the polarizing plate is held by the liquid crystal cell. Further, in the above aspect, the protective film disposed on the liquid crystal cell side may be the optical compensation film (transparent film) of the second aspect of the invention.

(protective film)

The polarizing plate which can be used in the second aspect of the present invention may be a pair of protective films (also referred to as protective films) in the two-layer layer of the polarizing film. The type of the protective film is not particularly limited, and cellulose esters such as cellulose acetate, cellulose acetate butyrate, and cellulose propionate, polycarbonate, polyolefin, polystyrene, polyester, and the like can be used. In the above aspect, a deuterated cellulose film satisfying the optical characteristics of the above transparent film can also be used as the protective film.

The protective film is generally supplied in the form of a roll, and it is preferable to continuously bond the long polarizing film so that the longitudinal direction thereof is uniform. Here, the alignment axis (slow phase axis) of the protective film may be in any direction, and the alignment axis of the protective film is preferably parallel to the longitudinal direction in terms of ease of handling.

In the case where optical compensation energy is applied to the protective film, the ratio of Re to Rth (450 nm) in the wavelength of 450 nm in the visible light region is 0.39 to 0.95 times the Re/Rth (550 nm) in the wavelength of 550 nm, and the wavelength is 650 nm. The Re/Rth (650 nm) is 1.04 to 2.20 times the Re/Rth (550 nm) at a wavelength of 550 nm, and the retardation value Rth in the thickness direction at a wavelength of 550 nm in the visible light region of the transparent film is preferably 70 nm to 400 nm.

On the other hand, in the case where the protective film does not have a function as a transparent film, the hysteresis value of the transparent protective film is preferably low, and the alignment axis of the polarizing film and the alignment axis of the transparent protective film are not parallel. In particular, when the hysteresis value of the transparent protective film is equal to or greater than a certain value, since the alignment axis (late phase axis) of the polarizing film and the transparent protective film is skewed, the linearly polarized light becomes a circularly polarized light and is not preferable. The polymer film having a low hysteresis value is preferably a polyolefin such as cellulose triacetate, ZEONEX, ZEONOR (all manufactured by ZEON Co., Ltd.) or ARTON (manufactured by JSR Co., Ltd.). In addition, the non-birefringent optical resin material described in Japanese Laid-Open Patent Publication No. Hei. No. Hei. In this aspect, in the case where a laminate composed of a support and an optically anisotropic layer composed of a liquid crystalline compound on the support is used as the light compensation layer, the protective film also has an optical anisotropic layer. Support body.

When the protective film and the polarizing film are bonded, the retardation axis (alignment axis) and the polarizing film are absorbed by at least one of the protective films (the protective film disposed on the liquid crystal cell side when assembled to the liquid crystal display device) It is preferable that the shaft (extension axis) is formed in a cross shape, and a protective film and a polarizing film are laminated. Specifically, the angle of the absorption axis of the polarizing film and the slow axis of the protective film is preferably 10° to 90°, preferably 20° to 70°, more preferably 40° to 50°, and particularly preferably 43. ~47°. The angle between the slow axis of the other protective film and the absorption axis of the polarizing film is not particularly limited, and may be appropriately set according to the purpose of the polarizing plate, and it is preferable in the above range to make the retardation axes of the pair of protective films uniform. It is better.

Further, when the retardation axis of the protective film and the absorption axis of the polarizing film are parallel to each other, the dimensional stability of the polarizing plate or the mechanical stability of the curled polarizing plate is prevented from being improved. When at least two axes of the total of the three films of the polarizing film and the pair of protective films, the slow axis of one of the protective films, the absorption axis of the polarizing film, or the slow axis of the two protective films are substantially parallel, the same can be obtained. Effect.

"Binder"

The adhesive film of the polarizing film and the protective film is not particularly limited, and examples thereof include a PVA resin (modified PVA containing an ethyl acetonitrile group, a sulfonic acid group, a carboxyl group, or an alkyloxy group), or an aqueous solution of a boron compound. Among them, PVA resin is preferred. The thickness of the layer is preferably 0.01 to 10 μm after drying, and particularly preferably 0.05 to 5 μm.

"The consistent manufacturing steps of polarizing film and transparent protective film"

The polarizing plate used in the second aspect of the present invention may have a drying step of shrinking and lowering the volatility after stretching the film for a polarizing film, or at least one side may be transparent after drying or drying. After the protective film, it is preferred to have a post-heating step. In the aspect in which the transparent protective film is a support which is an optically anisotropic layer which functions as a transparent film, a transparent protective film is bonded to one side, and a transparent support having an optically anisotropic layer is bonded to the opposite side. After that, it is better to perform post-heating. The specific adhesion method is to use a bonding agent to adhere the transparent protective film to the polarizing film while maintaining the both ends, and then trim the two ends, or after drying, from the both ends of the film. A method of removing a film for a polarizing film, and affixing both ends of the film to adhere a transparent protective film. As a method of trimming, a general technique such as a cutting method of a cutting machine such as a blade or a method using a laser can be used. After bonding, it is preferred to heat the adhesive in order to dry the adhesive and to improve the polarizing performance. The heating conditions vary depending on the adhesive, and in the case of a water system, it is preferably 30 ° C or more, more preferably 40 ° C to 100 ° C, still more preferably 50 ° C to 90 ° C. These steps are better in terms of performance and productivity when manufactured in a consistent production line.

"Performance of polarizing plates"

The optical properties and durability (short-term, long-term storage stability) of the polarizing plate composed of the transparent protective film, the polarizer, and the transparent support used in the second aspect of the present invention are commercially available as super advanced. Comparative products (for example, HLC 2-5618 manufactured by SUNRITZ Co., Ltd.) are preferably equal or higher. Specifically, the visible light transmittance is 42.5% or more, and the degree of polarization {(Tp-Tc) / (Tp + Tc)} 1/2 ≧ 0.9995 (where Tp is parallel penetration and Tc is orthogonal transmittance) The rate of change in light transmittance before and after being placed in an environment of 60 ° C, a humidity of 90% RH for 500 hours and at 80 ° C for 500 hours in a dry environment is based on an absolute value of 3% or less, more preferably 1 Below %, the rate of change in the degree of polarization is based on an absolute value of 1% or less, more preferably 0.1% or less.

Example

Hereinafter, the examples are given to further illustrate the present invention. The materials, reagents, ratios, operations, and the like shown in the following examples can be appropriately changed without departing from the spirit of the invention. However, the scope of the invention is not limited to the embodiments shown below.

[Example 1-1] <Production of cellulose acetate film>

The following composition was placed in a mixing tank, stirred while heating, and each component was dissolved to prepare a cellulose acetate solution.

Cellulose acetate solution

Degree of vinegar 60.7~61.1% cellulose acetate 100 parts by mass of triphenyl phosphate (plasticizer) 7.8 parts by mass of biphenyldiphenyl phosphate (plasticizer) 3.9 parts by mass of dichloromethane (first solvent) 336 parts by mass Methanol (second solvent) 29 parts by mass of 1-butanol (third solvent) 11 parts by mass

In the other mixing tank, 16 parts by mass of the following retardation value increasing agent, 92 parts by mass of dichloromethane, and 8 parts by mass of methanol were charged, and stirred while heating to prepare a hysteresis value rising agent solution. In 474 parts by mass of the cellulose acetate solution, 25 parts by mass of the hysteresis value rising agent solution was mixed, and the mixture was sufficiently stirred to prepare a dope. The amount of the hysteresis value-increasing agent added was 6.0 parts by mass based on 100 parts by mass of the cellulose acetate.

Hysteresis value riser

The resulting dope was cast using a conveyor belt extender. Since the film surface temperature on the conveyor belt was 40 ° C, it was dried by warm air at 70 ° C for 1 minute, and the film from the conveyor belt was dried by dry air at 140 ° C for 10 minutes to prepare acetic acid having a residual solvent amount of 0.3% by mass. Cellulose film (thickness: 80 μm). For the cellulose acetate film (transparent support, transparent protective film) to be produced, an automatic hysterometer (KOBRA 21ADH, manufactured by Oji Scientific Instruments Co., Ltd.) was used to measure the Re hysteresis value and the Rth hysteresis value at a wavelength of 633 nm. . Re is 8 nm and Rth is 78 nm. The produced cellulose acetate film was immersed in a 2.0 N potassium hydroxide solution (25 ° C) for 2 minutes, neutralized with sulfuric acid, washed with pure water, and then dried. Then, a cellulose acetate film for a transparent protective film was produced.

<Formation of alignment film>

On the cellulose acetate film, a coating liquid having the following composition was applied to 28 mL/m ^{2 with} a wire rod coater of #16. The drying was carried out by using a warm air of 60 ° C for 60 seconds and then using a warm air of 90 ° C for 150 seconds. Next, rubbing treatment (i.e., friction shaft system and cellulose acetate) is performed on the formed film so as to be aligned parallel to the in-plane slow axis of the cellulose acetate film (casting direction and parallel direction). The slow phase axes of the films are parallel).

Orientation film coating composition

The following modified polyvinyl alcohol 20 parts by mass of water 360 parts by mass of methanol 120 parts by mass of glutaraldehyde (crosslinking agent) 1.0 part by mass

Modified polyvinyl alcohol

<Formation of optical anisotropic layer>

On the alignment film, 91.0 g of the following disc-shaped (liquid crystal) compound and ethylene oxide were changed to trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Co., Ltd.), and butyl acetate. Acid cellulose (CAB551-0.2, manufactured by Eastman Chemical Co., Ltd.) 2.0 g, cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co., Ltd.) 0.5 g, photopolymerization initiator (IRGACURE-907, CIBA-) 1.0 g of GEIGY Co., Ltd., 1.0 g of sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.), and a copolymer of fluoroaliphatic group (manufactured by MEGAFAX F780 Dainippon Ink Co., Ltd.) 1.3 g dissolved in 207 g The coating liquid of methyl ethyl ketone was coated with a wire rod of #3.6 to 6.2 ml/m ² . This was heated in a constant temperature zone at 130 ° C for 2 minutes to align the discotic compound. Next, a 120 W/cm high pressure mercury lamp was used in an environment of 60 ° C, and UV was irradiated for 1 minute to polymerize the disk-shaped compound. Then, let cool to room temperature. An optically anisotropic layer is formed by this or the like to fabricate an optical compensation sheet.

Liquid crystalline discotic compound (A)

In the optically anisotropic layer produced, the discotic liquid crystalline compound is formed at an angle (inclination angle) between the disk surface and the transparent protective film, and increases from the transparent protective film to the air interface at an average inclination angle of 37°. To carry out the hybrid alignment. The optically anisotropic layer is a uniform film having no defects such as streaks. The thickness of the optically anisotropic layer formed was 1.7 μm. The tilt angle was calculated by an automatic birefringence meter (MKOBRA 21ADH, manufactured by Oji Scientific Instruments Co., Ltd.).

When the polarizing plate was arranged in a crossed Nicols and the unevenness of the obtained optical compensation sheet was observed, and the direction was inclined from the front surface and the normal line to 60°, no unevenness was observed.

(production of polarized photons)

PVA having an average degree of polymerization of 4000 and a degree of saponification of 99.8 mol% was dissolved in water to obtain a 4.0% aqueous solution. This solution was formed by casting and drying a conveyor belt using a tapered die to have a width of 110 mm before stretching and a thickness of 120 μm at the left end and 135 μm at the right end.

The film was peeled off from the conveyor belt, and stretched obliquely in a 45 degree direction in a dry state, and immersed in an aqueous solution of 0.5 g/L of iodine and 50 g/L of potassium iodide at 30 ° C for 1 minute, followed by 100 g of boric acid. L. An aqueous solution of potassium iodide 60 g/L was immersed at 70 ° C for 5 minutes, then washed with water at 20 degrees for 10 seconds in a water washing tank, and then dried at 80 ° C for 5 minutes to obtain an iodine-based polarizer. The polarizer has a width of 1340 mm and a thickness of about 20 μm.

A polarizing film for adsorbing iodine was prepared on the stretched polyvinyl alcohol film, and the optical compensation sheet produced was adhered to one side of the support surface and the polarizing film using a polyvinyl alcohol-based adhesive. Further, a cellulose triacetate film (TD-80U, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm was subjected to a saponification treatment, and adhered to the opposite side of the polarizing film using a polyvinyl alcohol-based adhesive. The absorption axis of the polarizing film and the slow axis of the optical compensation sheet support (direction parallel to the casting direction) are arranged to be perpendicular. Thus, a polarizing plate is produced.

In the produced TN unit cell, the produced polarizing plate was adhered to each other on the observer side and the backlight side through an adhesive, so that the optical compensation sheet was formed on the liquid crystal cell side. At this time, the absorption axis direction of the polarizing plate and the alignment control direction of the optical compensation sheet were adjusted so as to be parallel to the rubbing direction of the opposite liquid crystal cell to fabricate a liquid crystal display device.

[Example 1-2] (production of support)

The following composition was placed in a mixing tank, stirred while heating, and each component was dissolved to prepare a cellulose acetate solution.

In the other mixing tank, 16 parts by mass of the hysteresis-increasing agent, 80 parts by mass of dichloromethane, and 20 parts by mass of methanol were charged, and the mixture was stirred while heating to prepare a hysteresis-increasing agent solution.

In 464 parts by mass of the cellulose acetate solution, 36 parts by mass of the hysteresis-increasing agent solution and 1.1 parts by mass of vermiculite fine particles (R972, manufactured by IRONZINE Co., Ltd.) were mixed, and the mixture was sufficiently stirred to prepare a dope. The amount of the hysteresis value-increasing agent added was 5.0 parts by mass based on 100 parts by mass of the cellulose acetate. Further, the amount of the fine particles of the vermiculite is 0.15 parts by mass based on 100 parts by mass of the cellulose acetate.

The resulting paste was cast using a casting machine having a conveyor belt having a width of 2 m and a length of 65 m. Since the film surface temperature on the conveyor belt was 40 ° C, it was dried and peeled off after 1 minute, and then spread at a width of 140 ° C using a tenter at 28 ° in the width direction. Thereafter, it was dried by dry air at 135 ° C for 20 minutes to produce a transparent support having a residual solvent amount of 0.3% by mass.

The transparent support has a width of 1340 mm and a thickness of 46 μm.

The transparent support was tempered and conditioned at a temperature of 20 ° C and a relative humidity of 20% for 2 hours, and the hysteresis value at a wavelength of 590 nm was measured by an automatic birefringence meter (KOBRA 21ADH, manufactured by Oji Scientific Instruments Co., Ltd.). At (Re), it was 19.0 nm. Further, when the hysteresis value (Rth) at a wavelength of 59 onm was measured, it was 88 nm.

Next, the transparent support was tempered and conditioned under conditions of a temperature of 10 ° C and a relative humidity of 20% for 2 hours, and the hysteresis value (Re) at a wavelength of 633 nm was measured in the same manner to be 18.9 nm. Further, when the hysteresis value (Rth) at a wavelength of 633 nm was measured, it was 87.6 nm.

On a conveyor belt side of the transparent support, a 1.0 N potassium hydroxide solution (solvent: water / isopropanol / propylene glycol = 69.2 parts by mass / 15 parts by mass / 15.8 parts by mass) was applied at 10 ml/m ² at about 40 After the state of °C was maintained for 30 seconds, the lye was scraped off, washed with pure water, and the water droplets were removed with a spatula. Subsequently, it was dried at 100 ° C for 15 seconds. The contact angle of the alkali-treated surface with respect to pure water was measured to be 42°. On the same support, the same coating liquid for forming an optically anisotropic layer as that used in Example 1-1 was applied to form an optically anisotropic layer, and then bonded to a polarizing film by a roll-in/roll-out method to form a coating film. Become outside. The other configurations are the same as those in the embodiment 1-1.

[Example 1-3]

A liquid crystal display device having the same configuration as that shown in Fig. 1 was produced. That is, the outer protective film 1, the polarizing film 3, the support 5, the optical compensation film 7, the liquid crystal cell 9, the liquid crystal layer 11, the lower substrate 13, the optical compensation film 14, and the lower polarizing plate protective film are laminated from the observation direction (upper). 16. The lower side of the polarizing film outer protective film 20 is subjected to optical simulation of the liquid crystal display device including the backlight source 22, and the effect is confirmed. The optical calculation system uses LCD Master Ver6.08 manufactured by SHINTECH. The liquid crystal cell or electrode, the substrate, the polarizing plate, and the like are used in accordance with the values of materials conventionally used for liquid crystal displays. The alignment of the liquid crystal cells is such that the upper and lower substrates have a pretilt angle of 3 degrees, the cell gap of the substrate is 5.2 μm, and the hysteresis value of the liquid crystal (that is, the product of the thickness d (micrometer) of the liquid crystal layer and the refractive index anisotropy Δn Δ N.d) is 400 nm at a wavelength of 550 nm and 385 nm at a wavelength of 633 nm. The light source is a C light source attached to the LCD Master. Further, in the liquid crystal display device having the first embodiment, even if the relationship between the backlight and the observer is changed up and down, the same result can be obtained. The Re and Rth of the support were changed under the above conditions to simulate, and the Re and Rth of the support were changed to follow the contrast change behavior of 60° in the downward direction.

Fig. 2 is a graph showing a comparison value of 60° in the lower direction when the protective film Re and Rth are changed. When the graph is 25+Re (633) ≦ Rth ≦ 250-Re (633), the comparison is 10 or more, and it is known that high contrast characteristics can be obtained.

For detailed calculations, the range of 25+Re(633)≦Rth≦175+Re(633) and Rth≦250-Re(633) is preferred. In more detailed calculations, if 50+Re(633)≦Rth≦150+Re(633) and Rth≦150-Re(633), it is known that a comparison of 10 or more can be obtained at a viewing angle of 80°.

Further, it is known that the absolute value of Re is 5 nm or more, and Re and Rth are preferably one-half or less of the liquid crystal layer hysteresis value Δnd.

[Comparative Example 1-1]

In Example 1-1, the absorption axis of the polarizing film and the slow axis (the casting direction and the parallel direction) of the optical compensation sheet support were arranged in parallel.

(Evaluation of TN liquid crystal cells)

A pair of polarizing plates provided in a liquid crystal display device (AQUOS LC20C1S, manufactured by SHARP) using TN liquid crystal cells are peeled off, and the hysteresis value of the liquid crystal layer and the twist direction of the liquid crystal are widely used by SHINTECH. The measurement was performed using the deflection analyzer H33. The hysteresis value was about 0.4 μm, and the liquid crystal cell line was viewed from the light source side toward the display observation side, and when viewed from the observation side, it was confirmed that the clockwise direction was rotated by about 90°. In place of the stripped polarizing plate, the polarizing plates produced in Examples 1-1 and 1-2 and the polarizing plate produced in Comparative Example 1-1 were adhered to each other on the observer side and the backlight side through an adhesive. The optical compensation film is on the liquid crystal cell side.

The liquid crystal display device produced was measured using a measuring machine (EZ-Contrast 160D, manufactured by ELDIM Co., Ltd.) at eight stages from black display (L0) to white display (L7). In the liquid crystal display devices of Examples 1-1 to 2 and Comparative Example 1-1, the viewing angles of 10 or more in the upper and lower directions are as shown in Table 1-1.

Viewing angle: the angle of reversal from the polar angle of the display normal direction of 10 or more: the angle of the brightness of each of L1 and L2 is reversed

Example 1-1 is an example in which a polarizing plate in which a retardation axis of a support is orthogonal to an absorption axis of a polarizing film, and Example 1-2 is a late phase in which a support is produced by a roll-in/out method. A polarizing plate in which the axis and the absorption axis of the polarizing film are orthogonal to each other, and an example of the polarizing plate is used. In the embodiment 1-3, as in the above, a model of a polarizing plate in which the slow axis of the support is orthogonal to the absorption axis of the polarizing film is used, and the Re and Rth of the support are changed by the simulation to track the change of the contrast. example. Comparative Examples 1-1 to 1-4 All of Examples 1-1 to 1-4 were excellent, but Examples 1-1 to 1-3 in which a polarizing plate in which the slow axis of the support and the absorption axis of the polarizing film were orthogonal were used. It is known that the contrast viewing angle is particularly enlarged.

[Example 2-1]

The liquid crystal display device having the configuration shown in Fig. 3 was subjected to optical simulation to confirm the effect. The optical calculation system uses LCD Master Ver6.08 manufactured by SHINTECH. The liquid crystal cell or electrode, the substrate, the polarizing plate, and the like are used as they are in the conventional liquid crystal display. The liquid crystal material is ZLI-4792 attached to the LCD Master. The alignment of the liquid crystal cells forms a horizontal alignment of parallel alignment at a pretilt angle of 4 degrees, the cell gap of the substrate is 4 micrometers, and the liquid crystal material having a positive dielectric anisotropy and hysteresis value of the liquid crystal (ie, the thickness of the liquid crystal layer) The product Δn.d) of d (micrometer) and the refractive index anisotropy Δn is 395 nm. The polarizing film is a G1220DU attached to the LCD Master. The values of Re and Rth of the transparent film wavelength were set to the values shown in the column of Example 2-1 of Table 2-1. Further, the front side Re hysteresis value of the optically anisotropic layer was set to 30 nm. The light source uses a Backlight source attached to the LCD Master. Thus, the liquid crystal display device of Example 2-1 was formed into the configuration shown in Fig. 3. However, the angle of intersection between the transmission axis 52 of the polarizing film 51 and the in-plane retardation axis 53a of the transparent film 53, and the intersection angle between the transmission axis 62 of the polarizing film 61 and the in-plane retardation axis 63a of the transparent film 63 are It is 0°.

<Light leakage and chromaticity of liquid crystal display device>

In the liquid crystal display device of Example 2-1, a voltage having a minimum front transmittance was applied, that is, a black voltage was applied, and black at an azimuth angle of 270° and a polar angle of 60° at a viewing angle was obtained. Shows the penetration rate (%). The results are shown in Table 2-1.

[Example 2-2~2-4]

In the same manner as in Example 2-1, Re and Rth were formed to form a transparent film having optical characteristics as shown in Table 2-1. Except for this, the optical characteristics of the liquid crystal display device were obtained by the LCD Master calculation in the same manner as in Example 2-1.

<Measurement of light leakage and chromaticity of liquid crystal display device>

In the liquid crystal display device, the voltage at which the front surface transmittance is the smallest, that is, the black voltage is applied, and the black display transmittance in the viewing angle of 270° in the polar angle and 60° in the polar angle is obtained. (%). The results are shown in Table 2-1.

[Comparative Example 2-1]

In the same manner as in Example 2-1, Re and Rth were formed to form a transparent film having optical characteristics as shown in Table 2-1. Except for this, the optical characteristics of the liquid crystal display device were obtained by the LCD Master calculation in the same manner as in Example 2-1. In Comparative Example 2-1, in comparison with the effect of the second aspect of the present invention, the Re/Rth ratio of the ratio of Re to Rth is substantially constant even at any wavelength of 450, 550, and 650 nm.

<Measurement of light leakage and chromaticity of liquid crystal display device>

In the liquid crystal display device, the voltage at which the front surface transmittance is the smallest, that is, the black voltage is applied, and the black display transmittance in the viewing angle of 270° in the polar angle and 60° in the polar angle is obtained. (%). The results are shown in Table 2-1.

According to the results shown in Table 2-1, Re/Rth (450 nm) is 0.39 to 0.95 times Re/Rth (550 nm), and Re/Rth (650 nm) is 1.04 to 2.20 times Re/Rth (550 nm). In the second to fourth embodiments of the liquid crystal display device of the second aspect of the present invention, all of them are compared with the comparative example 2-1, and it is known that the transmittance at the time of black display at a polar angle of 60° is lowered. . Further, according to the results of Table 2-1, when Re/Rth (450 nm) is 0.56 times Re/Rth (550 nm) and Re/Rth (650 nm) is 1.69 times Re/Rth (550 nm), it is understood that Its penetration rate and color shift are all minimal.

1. . . Upper polarizer outer protective film

2. . . Upper side polarizer outer protective film slow phase axis

3. . . Upper polarizing film

4. . . Upper polarizing plate polarizing film absorption axis

5. . . Upper polarizing plate liquid crystal cell side protective film (support)

6. . . Upper polarizing plate liquid crystal cell side protective film (support) slow phase axis

7. . . Upper optical anisotropic layer

8. . . Friction direction of the alignment of the support side of the upper optically anisotropic layer

9. . . Liquid crystal cell upper substrate

10. . . The rubbing direction of the liquid crystal alignment of the upper substrate

11. . . Liquid crystal molecule

12. . . Friction direction of liquid crystal alignment of lower substrate

13. . . Liquid crystal cell side substrate

14. . . Lower optical anisotropic layer

15. . . Friction direction of the alignment of the support side of the lower optical anisotropic layer

16. . . Lower polarizing plate liquid crystal cell side protective film (support)

17. . . Lower polarizer liquid crystal cell side protective film (support) slow phase axis

18. . . Lower polarizer film

19. . . Absorption axis of polarizing film of lower polarizing plate

20. . . Lower polarizer outer protective film

twenty one. . . Lateral polarizer outer protective film slow phase axis

twenty two. . . Backlight

51. . . Polarizing film

52. . . Penetration axis

53. . . Transparent film

53a. . . In-plane retardation axis

55. . . Optical anisotropic layer

55a. . . Orientation average direction of the polarizing film side (transparent film interface side) of the molecular symmetry axis of the liquid crystal compound

56. . . Substrate

57. . . Liquid crystalline molecule

58. . . Substrate

59. . . Optical anisotropic layer

59a. . . Orientation average direction of the polarizing film side (transparent film interface side) of the molecular symmetry axis of the liquid crystal compound

61. . . Polarizing film

62. . . Penetration axis

63. . . Transparent film

63a. . . In-plane retardation axis

73. . . Transparent support of optical anisotropic layer

83. . . Transparent support of optical anisotropic layer

Fig. 1 is a schematic view showing an example of the liquid crystal display device of the first aspect of the present invention.

Fig. 2 is a graph showing the relationship between the Re and Rth of the support film of the compensation film according to the first aspect of the present invention and the direction of the liquid crystal cell under the TN mode.

Fig. 3 is a schematic view showing a configuration example of the liquid crystal display device according to a second aspect of the present invention.

Fig. 4 is a graph showing optical characteristics of an example of a transparent film used in the second aspect of the present invention.

Fig. 5 is a schematic view showing a Bowingka ball used for explaining a change in the polarization state of incident light in an example of a conventional liquid crystal display device.

Fig. 6 is a schematic view showing a Bowingka ball used for explaining a change in the polarization state of incident light in the liquid crystal display device of the second aspect of the present invention.

Fig. 7 is a schematic view showing a configuration example of a conventional liquid crystal display device of the TN mode.

1. . . Upper polarizer outer protective film

2. . . Upper side polarizer outer protective film slow phase axis

3. . . Upper polarizing film

4. . . Upper polarizing plate polarizing film absorption axis

5. . . Upper polarizing plate liquid crystal cell side protective film (support)

6. . . Upper polarizing plate liquid crystal cell side protective film (support) slow phase axis

7. . . Upper optical anisotropic layer

8. . . Friction direction of the alignment of the support side of the upper optically anisotropic layer

9. . . Liquid crystal cell upper substrate

10. . . The rubbing direction of the liquid crystal alignment of the upper substrate

11. . . Liquid crystal molecule

12. . . Friction direction of liquid crystal alignment of lower substrate

13. . . Liquid crystal cell side substrate

14. . . Lower optical anisotropic layer

15. . . Friction direction of the alignment of the support side of the lower optical anisotropic layer

16. . . Lower polarizing plate liquid crystal cell side protective film (support)

17. . . Lower polarizer liquid crystal cell side protective film (support) slow phase axis

18. . . Lower polarizer film

19. . . Absorption axis of polarizing film of lower polarizing plate

20. . . Lower polarizer outer protective film

twenty one. . . Lateral polarizer outer protective film slow phase axis

twenty two. . . Backlight

Claims (10)

A liquid crystal display device comprising: a pair of substrates including at least one electrode and arranged in a pair, a liquid crystal layer disposed between the substrates, and a first polarizing plate disposed outside the liquid crystal layer; Wherein the thickness d (μm) of the liquid crystal layer and the product of the refractive index anisotropy Δn Δn. d is 0.2 to 1.2 μm, and the alignment state of the liquid crystal layer is changed by applying an electric field of at least two or more values, and when no application is applied to the electric field when an electric field is applied, the average alignment angle of the substrate surface of the liquid crystal layer is Differently, the first polarizing plate includes a polarizing film, and a pair of protective films disposed to hold the polarizing film, and the optical device is positioned close to the liquid crystal layer on the outer side of the protective film, and is optically fixed to a discotic compound in a misaligned state. In the non-directional layer, at least one of the pair of protective films is a liquid crystal display device satisfying the following formulas (I) and (II), (I) 25+Re (633) ≦ Rth ≦ 250-Re (633) [wherein, Re(λ) is the front side hysteresis value (unit: nm) in the wavelength λnm, Rth(λ) is the hysteresis value (unit: nm) in the film thickness direction in the wavelength λnm, and d is the thickness of the film], ( II) 5≦|Re(633)|. The liquid crystal display device of claim 1, wherein Δnd of the liquid crystal layer and Re and Rth of at least one side of the protective film satisfy the following formulas (III) and (IV) at a wavelength of 400 to 700 nm, ( III) Rth≦Δnd/2 (IV) Re≦Δnd/2. The liquid crystal display device of claim 1, wherein a retardation axis of the protective film adjacent to the liquid crystal layer intersects the absorption axis of the polarizing film. A polarizing plate comprising: a polarizing film; a pair of protective films disposed to hold the polarizing film; and an optical anisotropic layer disposed on the outer side of the protective film and fixed to a discotic compound in a mixed alignment state, At least one of the pair of protective films satisfies the following formulas (I) and (II), (I) 25+Re (633) ≦ Rth ≦ 250-Re (633) [wherein, Re(λ) is The front side hysteresis value (unit: nm) in the wavelength λnm, Rth(λ) is the hysteresis value (unit: nm) in the film thickness direction at the wavelength λnm, and d is the thickness of the film], (II) 5≦|Re(633) |. The polarizing plate of claim 4, wherein the polarizing film and the pair of protective films are laminated by roll-to-roll. An optical compensation film comprising at least a transparent film and an optically anisotropic layer having an optically anisotropic layer in the plane, wherein the transparent film has an in-plane hysteresis value of Re and a thickness direction hysteresis value of Rth In the case of the ratio of Re to Rth at a wavelength of 450 nm, Re/Rth (450 nm) It is 0.39 to 0.95 times Re/Rth (550 nm) at a wavelength of 550 nm, Re/Rth (650 nm) is 1.04 to 2.20 times Re/Rth (550 nm) at a wavelength of 650 nm, and Rth is 70 nm at a wavelength of 550 nm. ～400 nm, the optically anisotropic layer is formed of a composition containing a liquid crystal compound in which a molecular system of the liquid crystal compound is fixed in an alignment state, and a molecular symmetry axis of the liquid crystal compound At least the alignment average direction in the transparent film side interface, when the direction of the orthographic projection in the transparent film surface is opposite to the in-plane slow axis of the transparent film, is substantially 0 degree or substantially 90 degrees. The optical compensation film of claim 6, wherein the liquid crystalline compound is a discotic liquid crystalline compound. A liquid crystal display device characterized by comprising: a liquid crystal cell having at least one electrode and a pair of substrates arranged in opposite directions, sandwiched between the pair of substrates, containing a nematic liquid crystal material, and when not driven The liquid crystal molecules of the nematic liquid crystal material have a product of a slightly parallel alignment, a thickness d (micrometer) and a refractive index anisotropy Δn with respect to the surface of the pair of substrates Δn. d is a liquid crystal layer of 0.1 to 1.5 μm; holding the first and second polarizing films disposed on the liquid crystal cell; and having a transparent film between at least one side of the first and second polarizing films and the liquid crystal cell, the transparent In the case where the in-plane hysteresis value of the film is Re and the hysteresis value in the thickness direction is Rth, the ratio of Re to Rth (450 nm) at a wavelength of 450 nm is 0.39 of Re/Rth (550 nm) at a wavelength of 550 nm. 0.95 times, Re/Rth (650 nm) is 1.04 to 2.20 times of Re/Rth (550 nm) at a wavelength of 650 nm, and Rth is 70 nm to 400 nm at a wavelength of 550 nm of the transparent film, between the transparent film and the liquid crystal cell. At least one optically anisotropic layer formed of a composition containing a liquid crystal compound in which the molecular system of the liquid crystalline compound is fixed in an alignment state and liquid crystal The orientation average direction of the molecular symmetry axis of the compound at least in the transparent film side interface, when the direction of the orthographic projection in the plane of the transparent film, the intersection angle with the in-plane slow axis of the transparent film is substantially 0 degree Or roughly 90 degrees. The liquid crystal display device of claim 8, wherein the liquid crystalline compound is a discotic liquid crystalline compound. The liquid crystal display device of claim 8 or 9, wherein the liquid crystal cell is a liquid crystal cell of a TN mode.