JP5970781B2 - Organic electroluminescence display device - Google Patents

Description

  The present invention relates to an organic electroluminescence display device, and more particularly to an organic electroluminescence display device including a circularly polarizing plate having a λ / 4 retardation film and an organic electroluminescence element.

  An organic electroluminescence element (hereinafter also referred to as an organic EL element) that emits light when a light emitting layer is provided between the electrodes and a voltage is applied thereto is used for flat illumination, optical fiber light source, liquid crystal display backlight, and liquid crystal projector Research and development are actively conducted as various light sources such as backlights and display devices. The organic EL element is an element that has attracted much attention in recent years because it exhibits excellent characteristics in terms of light emission efficiency, low voltage driving, light weight, and low cost, particularly in the above-mentioned fields of use.

  The organic EL element injects electrons from the cathode and holes from the anode, and recombines them in the light emitting layer, thereby generating visible light emission corresponding to the light emission characteristics of the light emitting layer.

  The anode is mainly composed of indium tin oxide (hereinafter abbreviated as ITO) because it has the highest electrical conductivity among transparent conductive materials, a relatively large work function, and high hole injection efficiency. ) Is used.

  On the other hand, a metal electrode is usually used for the cathode, but considering the electron injection efficiency, from the viewpoint of work function, materials such as Mg, Mg / Ag, Mg / In, Al, Li / Al are mainly used. Is used.

  These metal materials have a high light reflectivity and have a function of reflecting light emitted from the light emitting layer and increasing an emitted light amount (light emission luminance) in addition to a function as an electrode (cathode). That is, the light emitted in the cathode direction is mirror-reflected on the surface of the metal material that is the cathode, and is extracted as emitted light from the transparent ITO electrode (anode).

  However, in the organic EL element having such a structure, since the cathode has a mirror surface with a strong light reflectivity, the reflection of external light becomes noticeable in a state where no light is emitted.

  That is, the reflection of the room lighting is intense, and black color cannot be expressed in the bright place, and there is a problem that the bright room contrast is extremely low when used as a light source for a display device.

  A method of using a circularly polarizing element (also referred to as a circularly polarizing plate) for the purpose of suppressing external light reflection as described above has been disclosed (for example, see Patent Document 1). The circularly polarizing element used here is generally composed of a protective film, a polarizer, and a λ / 4 retardation film from the viewing side, and is absorbed by the circularly polarizing plate described in Patent Document 1. The linear linear polarizing plate and the λ / 4 retardation film are laminated so that their optical axes intersect at 45 degrees or 135 degrees.

  Here, when the λ / 4 retardation film is formed of, for example, one stretched film, the retardation of the stretched film is different from that of a certain wavelength due to wavelength dispersion in which the refractive index of the stretched film varies from wavelength to wavelength. Can be exactly ¼ wavelength, but at other wavelengths, the phase difference deviates from the ¼ wavelength, so that it does not function as a λ / 4 retardation film.

  That is, for example, when functioning as a λ / 4 retardation film for 550 nm green light, it is difficult to completely prevent reflection of red light having a longer wavelength or blue light having a shorter wavelength. Become.

  In general, polycarbonate-based resins and cycloolefin-based resins are mainly used as λ / 4 retardation films, and these resins can be directly bonded to a polarizer constituting a circularly polarizing plate. Difficult, pasting a polarizer through a cellulose protective film and an adhesive, or pasting and winding a protective film and a polarizer, and then laminating a λ / 4 retardation film through an adhesive layer separately doing. Moreover, even if it bonds directly, it has the problem that adhesiveness is weak with respect to a cellulosic resin, and also water drainage is bad.

  For the above problem, a λ / 4 retardation film made of a cellulose-based resin that can be directly bonded, particularly a λ / 4 retardation film having a slow axis in a direction that is neither perpendicular nor parallel to the major axis direction. Development of was desired.

  On the other hand, in order to realize a λ / 4 retardation film with the triacetyl cellulose resin used for the protective film, there is a problem that the film thickness becomes very thick. In response to the above problems, by using cellulose acetate propionate resin used as an optical compensation film for liquid crystal display devices, the triacetyl cellulose resin can be stretched at a high magnification to achieve a λ / 4 characteristic with a thin film. A method that can be achieved is disclosed (see, for example, Patent Document 2).

  However, as a result of further studies on the above technique by the inventor, the λ / 4 retardation film produced by stretching the cellulose acetate propionate resin at a high magnification is particularly preserved for a long period of time in a high temperature and high humidity environment. As a result, it has been found that a unique problem of increasing dimensional fluctuation and phase difference fluctuation appears. When a λ / 4 retardation film having such characteristics is incorporated in an organic electroluminescence display device, the visibility changes greatly depending on the use environment, particularly in digital signage, mobile and in-vehicle applications. Since the visibility changes remarkably, there is a problem in practical use. Further, it has been found that there is a problem that the organic electroluminescence device itself deteriorates when it is repeatedly used in an environment where the temperature and humidity conditions vary greatly.

Japanese Patent Laid-Open No. 8-322138 JP 2009-276442 A

  The present invention has been made in view of the above problems, and its problems are visibility and durability when stored for a long period of time in a high-temperature and high-humidity environment (image display unevenness resistance against environmental temperature changes), and saponification suitability. And providing an organic electroluminescence display device having an improved λ / 4 retardation film.

  As a result of earnestly examining the above problems, the present inventor can achieve excellent λ / 4 characteristics with a thin film when producing a λ / 4 retardation film by high-stretching using a cellulose acylate resin, and Even when stored in a high temperature and high humidity environment for a long period of time, dimensional fluctuations and phase difference fluctuations are suppressed, and as an organic electroluminescence display device excellent in visibility, durability and suitability for saponification, the total acyl group substitution degree ( According to the composition in which two or more kinds of cellulose acylate resins each having an average value) and a substitution degree (average value) of an acyl group having 3 or more carbon atoms in a specific range are mixed at a specific mass ratio, By producing a λ / 4 retardation film and incorporating the λ / 4 retardation film into an organic electroluminescence display device, the above-mentioned problems can be solved.

  Specifically, the above-described problem of the present invention is solved by the following means.

1. From the viewing side, in the organic electroluminescence display device having the protective film, the polarizer, the λ / 4 retardation film and the organic electroluminescence element in this order,
The λ / 4 retardation film is
The in-plane retardation Ro (550) measured with 550 nm light is 130 nm or more and 160 nm or less,
In-plane retardation Ro (650) measured with 650 nm light is 155 nm or more and 175 nm or less,
The ratio of the Ro (550) to the Ro (650) (Ro (550) / Ro (650)) is 0.80 or more and 0.90 or less,
At least as cellulose acylate, cellulose acylate A that simultaneously satisfies the conditions specified by the following formulas (1) and (2), and cellulose acylate B that simultaneously satisfies the conditions specified by the following formulas (3) and (4) And containing
An organic electroluminescence display device, wherein the mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) is 1.0 or more and 19.0 or less.

Equation _{(1) 2.5 ≦ Z 1 <} 3.0
Formula (2) 2.5 <= X <= 3.0
Formula (3) 2.0 ≦ Z ₂ <2.5
Formula (4) 0.5 <= Y <= 1.5
(In the formula, Z ₁ and Z ₂ each represent the total acyl group substitution degree of cellulose acylate, and X and Y each represent the substitution degree of an acyl group having 3 or more carbon atoms in cellulose acylate.)
2. 2. The organic material according to 1 above, wherein the value of the mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) is 2.0 or more and 9.0 or less. Electroluminescence display device.

3. 3. The organic electroluminescence according to 1 or 2 above, wherein Z ₁ in the cellulose acylate A satisfies a condition defined by the following formula (5) and X satisfies a condition defined by the following formula (6): Display device.

Formula (5) 2.7 ≦ Z ₁ ≦ 2.9
Formula (6) 2.7 ≦ X ≦ 2.9
4). In any one of 1 to 3, wherein Z ₂ in the cellulose acylate B satisfies a condition defined by the following formula (7), and Y satisfies a condition defined by the following formula (8): The organic electroluminescence display device described.

Formula (7) 2.3 ≦ Z ₂ <2.5
Formula (8) 0.8 <= Y <= 1.2
That is, the organic electroluminescence display device according to the first aspect of the present invention (hereinafter also referred to as an organic EL display device) includes a protective film, a polarizer, a λ / 4 retardation film, and an organic electroluminescence element from the viewing side. In the organic electroluminescence display device which has in order, the λ / 4 retardation film has an in-plane retardation Ro (550) measured with 550 nm light of 130 nm or more and 160 nm or less, and measured with 650 nm light. The retardation Ro (650) in the in-plane direction is 155 nm or more and 175 nm or less, and the ratio of the Ro (550) to the Ro (650) (Ro (550) / Ro (650)) is 0. 80 or more and 0.90 or less, and at least cellulose acylate represented by the formula (1) and And cellulose acylate A that simultaneously satisfies the conditions specified by the formula (2) and cellulose acylate B that simultaneously satisfies the conditions specified by the above formulas (3) and (4). The mass ratio of cellulose acylate B (cellulose acylate B / cellulose acylate A) is 1.0 or more and 19.0 or less. It is an object of the present invention to provide an organic EL display device including a λ / 4 retardation film having improved visibility and durability when stored and saponification suitability.

  The reason why the problems of the present invention can be solved by the above-described configuration defined in the present invention is presumed as follows.

  That is, a cellulose acylate having a low acyl group substitution degree that satisfies the condition defined by the formula (3) is excellent in retardation development and saponification suitability, but durability in a high temperature and high humidity environment, and Ro (550) / There is a problem of poor Ro (650) value. On the other hand, a cellulose acylate having a high substitution degree acyl group substitution degree that satisfies the condition defined by the formula (1) is excellent in durability under a high temperature and high humidity environment and a Ro (550) / Ro (650) value. , Have the problem of poor phase difference development and saponification suitability. By blending and adjusting two or more types of cellulose acylates having these conflicting advantages and disadvantages, retardation development property, suitability for saponification, durability under high temperature and high humidity environment, Ro (550) / Ro ( 650) Although it is thought that it is possible to control the value, simply mixing two types of cellulose acylates having different characteristics may cause a problem that the compatibility is insufficient and clouding occurs. found. Therefore, by further changing the substitution degree of the acyl group having 3 or more carbon atoms represented by X and Y to cellulose acylate satisfying the conditions defined by the formulas (2) and (4), The compatibility of cellulose acylate can be improved, and as a result, white turbidity is suppressed, and by introducing an acyl group having 3 or more carbon atoms, hydrophobicity is increased and saponification suitability is not deteriorated. It is estimated that the effect of improving the durability under high temperature and high humidity environment has increased.

  The organic EL display device of the invention according to claim 2 has a mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) in the λ / 4 retardation film of 2. It is 0 or more and 9.0 or less.

  By setting the mass ratio of cellulose acylate B to cellulose acylate A as defined above, it is possible to further improve the visibility, durability, and saponification suitability when stored for a long period of time in a high temperature and high humidity environment.

The organic EL display device of the invention according to claim 3 is a cellulose acylate A according to the present invention having a total acyl group substitution degree Z ₁ of 2.7 or more and 2.9 or less, and an acyl group having 3 or more carbon atoms. The degree of substitution X is 2.7 or more and 2.9 or less.

By total acyl group substitution degree Z ₁ and the number of carbon atoms of the cellulose acylate A according to the present invention is further restricting the substitution degree X of 3 or more acyl groups, when stored for a long period of time in an environment humidity more high temperature and high Visibility, durability, and suitability for saponification can be improved.

The organic EL display device of the invention according to claim 4 has an acyl group substitution degree Z ₂ of cellulose acylate B according to the invention of 2.3 or more and 2.5 or less, and an acyl group having 3 or more carbon atoms. The degree of substitution Y is 0.8 or more and 1.2 or less.

By total acyl further restricting the substitution degree Y degree of substitution Z ₂ and having 3 or more carbon atoms of the acyl groups of cellulose acylate B according to the present invention, when stored for a long period of time in an environment humidity more high temperature and high Visibility and durability, saponification suitability, in particular, saponification suitability can be improved.

  According to the present invention, an organic material having a λ / 4 retardation film having improved visibility and durability when stored for a long time in a high-temperature and high-humidity environment (image display unevenness resistance against environmental temperature changes) and saponification suitability. An electroluminescent display device can be provided.

It is an example of a structure of the organic electroluminescent display apparatus of this invention. It is a schematic diagram of the tenter which can be used for production of the λ / 4 retardation film according to the present invention. It is a schematic diagram explaining an example of the extending | stretching direction in the diagonal stretch tenter shown to (a) of FIG. 2, and (b). It is the schematic which shows an example (example which extends | stretches diagonally after extending | stretching from a long film original fabric roll) of the manufacturing method of (lambda) / 4 phase difference film applicable to this invention. It is the schematic which shows an example (example which extends continuously diagonally, without winding up a long film original fabric) of the manufacturing method of (lambda) / 4 phase difference film applicable to this invention. It is a schematic sectional drawing which shows the structure of the organic electroluminescent display apparatus produced in the Example.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

《Organic electroluminescence display device》
First, the outline | summary of a structure is demonstrated about the organic electroluminescent display apparatus of this invention.

  FIG. 1 shows an example of the configuration of the organic electroluminescence display device of the present invention.

  A metal electrode 102, an organic light emitting layer 103, a transparent electrode (ITO etc.) 104, an insulating layer 105, a sealing layer 106, and a film 107 (may be omitted) are sequentially formed on a substrate 101 using glass, polyimide, or the like shown in FIG. A circularly polarizing plate C in which a polarizer 109 is sandwiched between a λ / 4 retardation film 108 and a protective film 110 is provided on the organic EL element B having the organic EL display device A. The protective film 110 may have a surface antireflection layer 111. The thickness of the organic EL element is about 1 μm excluding the substrate 101.

  In general, in an organic EL display device, a metal electrode, an organic light emitting layer, and a transparent electrode are sequentially laminated on a transparent substrate to form an element (organic EL element) that is a light emitter. Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been. In addition, the detail of each structural requirement of an organic EL element is mentioned later.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device including an organic EL element having a transparent electrode on the surface side of an organic light emitting layer that emits light when a voltage is applied and a metal electrode on the back surface side of the organic light emitting layer, the surface side of the transparent electrode (visible) A polarizing plate can be provided on the side), and a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, if the retardation plate is composed of a λ / 4 retardation film and the angle formed by the polarization direction of the polarizing plate and the retardation plate is adjusted to π / 4, the mirror surface of the metal electrode can be completely shielded. it can.

  That is, the external light incident on the organic EL display device is transmitted only by the linearly polarized light component by the polarizing plate, and this linearly polarized light is generally elliptically polarized by the retardation plate. In particular, the retardation plate has a λ / 4 retardation. When the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4, the film is circularly polarized.

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

[Λ / 4 retardation film]
Details of the λ / 4 retardation film used in the circularly polarizing plate according to the present invention will be described.

  The λ / 4 retardation film means a film having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light). The λ / 4 retardation film is designed so that the in-plane retardation value Ro of the layer is about ¼ of the predetermined wavelength of light (usually in the visible light region).

  The λ / 4 retardation film according to the present invention has an in-plane retardation Ro (550) of 130 nm or more and 160 nm or less measured with light having a wavelength of 550 nm in an environment of 23 ° C. and 55% RH, and a wavelength of One of the features is that the in-plane retardation Ro (650) measured with 650 nm light is 155 nm or more and 175 nm or less.

  The λ / 4 retardation film according to the present invention gives a quarter wavelength retardation to all light in the visible light region, that is, reverse wavelength dispersion (Ro (450) <Ro (550) < A λ / 4 retardation film having Ro (650)) is preferable. Even in the case of positive wavelength dispersion, it is possible to achieve λ / 4 by laminating a λ / 4 retardation film and a λ / 2 plate. However, in the case of adopting a laminated structure, an increase in retardation in the thickness direction (Rth) Visibility decreases due to axial misalignment.

  The wavelength dispersion of the λ / 4 retardation film is such that the value of Ro (450) / Ro (650) is less than 1.00, preferably 0.97 or less, more preferably 0.95 or less. In particular, λ / 4 is preferable for green to red with high visual sensitivity, and in particular, the value of Ro (550) / Ro (650) is 0.80 or more and 0.90 or less. .

  The retardation Ro (550) referred to in the present invention is a retardation value represented by the following formula (i).

Formula (i)
Ro = (nx−ny) × d
In the formula (i), nx represents the refractive index in the slow axis x direction in the film plane, ny represents the refractive index in the y direction perpendicular to the x direction in the film plane, and d represents the film thickness (nm). Each refractive index is measured at a measurement wavelength of 550 nm in an environment of 23 ° C. and 55% RH.

  Similarly, retardation Ro (650) is a retardation value represented by the above formula (i) measured at a wavelength of 650 nm.

  Ro defined in the present invention can be measured using an automatic birefringence meter. For example, using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), calculate Ro by birefringence measurement at 550 nm or 650 nm in an environment of 23 ° C. and 55% RH. Can do.

  When the λ / 4 retardation film is laminated so that the angle between the slow axis and the transmission axis of the polarizer is substantially 45 °, a circularly polarizing plate is obtained. That is, both the λ / 4 retardation film and the polarizer are in the form of a long film, and the angle of the slow axis with respect to the longitudinal direction of the base film of the λ / 4 retardation film (that is, the orientation angle θ) is “substantially. If it is 45 ° in general, a long circularly polarized light with high productivity can be obtained by laminating and laminating a polarizer having a transmission axis or an absorption axis in a direction parallel to the longitudinal direction of the polarizing film. A plate film can be formed.

  Therefore, the orientation angle θ with respect to the longitudinal direction of the base film of the λ / 4 retardation film according to the present invention is preferably “substantially 45 °”. In the present invention, “substantially 45 °” is preferably in a range of 45 ° ± 10 ° with the longitudinal direction as a base point.

  More specifically, the orientation angle θ of the λ / 4 retardation film according to the present invention is preferably 45 ° ± 5 °, more preferably 45 ° ± 3 °, and 45 ° ± 2 °. More preferably, it is most preferably 45 ° ± 1 °.

[Circularly polarizing plate]
The circularly polarizing plate according to the present invention is composed of at least a polarizer and a λ / 4 retardation film, and can be used for an organic EL display device to shield specular reflection of a metal electrode of an organic EL light emitter. .

  Further, the circularly polarizing plate according to the present invention is obliquely stretched so that the angle of the slow axis (that is, the orientation angle θ) is “substantially 45 °” with respect to the longitudinal direction, and is elongated obliquely. It is preferable that it is a long circularly polarizing plate obtained by laminating a λ / 4 retardation film by roll-to-roll.

  In the organic EL display device of the present invention, the circularly polarizing plate according to the present invention preferably has an ultraviolet absorption function in order to prevent deterioration due to ultraviolet rays. It is preferable that the protective film on the viewing side has an ultraviolet absorption function because both the polarizer and the organic EL element can be protected from ultraviolet rays. However, the λ / 4 retardation film on the light emitter side also has an ultraviolet absorption function. From the viewpoint of further suppressing the deterioration of the organic EL element.

  The circularly polarizing plate according to the present invention uses a stretched polyvinyl alcohol doped with iodine or a dichroic dye as a polarizer, and is stuck in a configuration of (λ / 4 retardation film) / polarizer / protective film. Can be manufactured together. Details of the polarizer will be described later.

  The circularly polarizing plate can be constituted by further bonding a protective film on one surface of the circularly polarizing plate and a separate film on the opposite surface. The protective film and the separate film are used for the purpose of protecting the circularly polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.

[Cellulose acylate]
In the λ / 4 retardation film according to the present invention, the retardation development property is high, and even when the retardation film has a high retardation, it can be thinned, and a high retardation can be expressed. Even when the film is stretched at a high magnification, it has excellent visibility and durability when stored for a long period of time in a high temperature and high humidity environment, and excellent saponification properties.

  In the λ / 4 retardation film according to the present invention, at least cellulose acylate, cellulose acylate A that simultaneously satisfies the conditions defined by the following formulas (1) and (2), and the following formulas (3) and ( 4) containing cellulose acylate B that simultaneously satisfies the conditions specified in 4), and the value of the mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) is 1.0 or more, It is 19.0 or less.

Equation _{(1) 2.5 ≦ Z 1 <} 3.0
Formula (2) 2.5 <= X <= 3.0
Formula (3) 2.0 ≦ Z ₂ <2.5
Formula (4) 0.5 <= Y <= 1.5
Furthermore, the value of the mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) is preferably 2.0 or more and 9.0 or less.

Further, the total acyl group substitution degree Z ₁ of cellulose acylate A is 2.7 or more and 2.9 or less, and the substitution degree X of the acyl group having 3 or more carbon atoms is 2.7 or more and 2.9 or less. preferable.

Further, 2.3 or more as a total acyl group substitution degree _{Z 2} of the cellulose acylate B, and 2.5 or less, 0.8 or more as a substitution degree Y of 3 or more acyl group with a carbon number of 1.2 or less It is preferable that

  In the λ / 4 retardation film according to the present invention, by using cellulose acylate A that simultaneously satisfies the conditions defined by the above formulas (1) and (2), the thickness of the λ / 4 retardation film can be reduced and improved. High saponification suitability can be achieved.

  In addition, by using cellulose acylate B that simultaneously satisfies the conditions defined by the above formulas (3) and (4), the desired value of Ro (550) / Ro (650) can be achieved, and in a high temperature and high humidity environment. Excellent durability at can be achieved.

  In addition, it is a thin film by defining the value of the mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) in the range of 1.0 or more and 19.0 or less. However, it was possible to perform high-stretching, and to obtain properties excellent in visibility and durability when stored for a long period of time in a high-temperature and high-humidity environment, and saponification suitability.

The cellulose acylate according to the present invention can be obtained by acylating a cellulose raw material. For example, when the acylating agent is an acid anhydride (for example, acetic anhydride, propionic anhydride, butyric anhydride, etc.), an organic acid such as acetic acid or an organic solvent such as methylene chloride is used, and a proton such as sulfuric acid is used. The synthesis is performed using a sex catalyst. For example, when the acylating agent is acid chloride (CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ COCl), the reaction is performed using a basic compound such as an amine as a catalyst.

  Cellulose as a raw material for cellulose acylate is not particularly limited, and examples thereof include cotton linter, wood pulp (for example, derived from coniferous tree, derived from broadleaf tree), kenaf and the like. Moreover, the cellulose acylate obtained from them can be mixed and used at an arbitrary ratio.

The cellulose acylate applicable to the present invention can be produced by a known method. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.
As a specific method for controlling the total acyl group substitution degree Z ₁ or the total acyl group substitution degree Z ₂ of the cellulose acylate according to the present invention within the numerical range defined by the above formula (1) or formula (3), In preparing cellulose acylate according to the above synthesis method, 1) acylation reaction time, 2) acylation reaction time, 3) saponification aging conditions, etc. are controlled to obtain a desired total acyl group substitution degree. Can be obtained. For example, the total acyl group substitution degree can be increased by shortening the saponification aging time, and conversely, the total acyl group substitution degree can be adjusted low by increasing the saponification aging time.

  Further, the substitution degree X of the acyl group having 3 or more carbon atoms or the substitution degree Y of the acyl group having 3 or more carbon atoms of the cellulose acylate according to the present invention is defined by the above formula (2) or formula (4). As a specific method for controlling within the numerical range, when preparing cellulose acylate, A) a method of adjusting the ratio of acylating agents having different degrees of substitution, B) an acylating agent having 3 or more carbon atoms, By controlling conditions such as a method of sequentially reacting an acylating agent having less than 3 carbon atoms, the degree of substitution of acyl groups having a desired carbon number of 3 or more can be obtained. For example, by increasing the ratio of the acylating agent having 3 or more carbon atoms, the acyl group substitution degree having 3 or more carbon atoms in cellulose acylate can be set high, and conversely, 3 or more carbon atoms in the reaction. By reducing the ratio of the acylating agent and increasing the ratio of the acylating agent having less than 3 carbon atoms, the substitution degree of the acyl group having 3 or more carbon atoms can be adjusted to a low value.

  The method for measuring the total acyl group substitution degree and the substitution degree of an acyl group having 3 or more carbon atoms as defined in the present invention can be carried out according to ASTM D-817-91.

  From the viewpoint of suitability for saponification, the acyl group having 3 or more carbon atoms is preferably a propionyl group.

  The number average molecular weight (Mn) of cellulose acylate A or cellulose acylate B according to the present invention is preferably strong in the mechanical strength of a film having a range of 30000-300000. Furthermore, the thing of 50000-200000 is used preferably.

  The value of the ratio Mw / Mn of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the cellulose acylate is preferably 1.4 to 3.0.

  The number average molecular weight (Mn) and weight average molecular weight (Mw) of cellulose acetate can be determined by measurement using gel permeation chromatography (GPC).

  Specific measurement conditions are as follows.

-Solvent: Methylene chloride-Column: Shodex K806, K805, K803G (used by connecting 3 products made by Showa Denko KK)
-Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
・ Pump: L6000 (manufactured by Hitachi, Ltd.)
・ Flow rate: 1.0ml / min
Calibration curve: A calibration curve of 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 100000 to 500 was used. Thirteen samples are used at approximately equal intervals.

  In addition, in the λ / 4 retardation film according to the present invention, in addition to the cellulose acylate A and the cellulose acylate B according to the present invention, other cellulose resins may be used in combination as long as the object effects of the present invention are not impaired. May be.

〔Additive〕
In the λ / 4 retardation film according to the present invention, various plasticizers can be used in combination as an additive for the purpose of improving the fluidity and flexibility of the composition. Examples of plasticizers applicable to the present invention include phthalate ester plasticizers, fatty acid ester plasticizers, trimellitic acid ester plasticizers, phosphate ester plasticizers, polyester plasticizers, and sugar ester plasticizers. Agents, epoxy plasticizers, polyhydric alcohol ester plasticizers, and the like. It can be applied to a wide range of uses by selecting or using these plasticizers according to the use.

  The λ / 4 retardation film according to the present invention contains 2.0 to 15.0% by mass of an aromatic compound having at least three aromatic rings with respect to the total mass of the cellulose acylate. It is preferable for reducing the water content of the λ / 4 retardation film without impairing the moisture permeability of the.

  Although there is no limitation in particular as an additive used for this invention, For example, the compound which has an aromatic terminal ester type compound and a triazine ring is preferable. The aromatic terminal ester compound may be either an oligoester type or a polyester type, and the molecular weight is preferably in the range of 100 to 10,000, but is preferably in the range of 350 to 3000. The acid value is 1.5 mgKOH / g or less, the hydroxy value is 25 mgKOH / g or less, more preferably the acid value is 0.5 mgKOH / g or less, and the hydroxy value is 15 mgKOH / g or less.

  In the present invention, the aromatic compound having at least three aromatic rings is preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the λ / 4 retardation film. Part by mass is more preferable.

本発明で好ましく用いられる多価アルコールエステルは、２価以上の脂肪族多価アルコールとモノカルボン酸のエステルよりなり、分子内に芳香環またはシクロアルキル環を有することが好ましい。 Examples of various additives applicable to the present invention will be given below, but the present invention is not limited to these.

The polyhydric alcohol ester preferably used in the present invention comprises an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.

  The polyhydric alcohol used in the present invention is represented by the following general formula (a).

Formula (a)
R _1- (OH) _n
In the general formula (a), R ₁ represents an n-valent organic group, and n represents a positive integer of 2 or more. The OH group represents an alcoholic or phenolic hydroxyl group.

  Examples of preferable polyhydric alcohols include the following.

  Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane- Examples include 1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol.

  Of these, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for polyhydric alcohol ester, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used.

  It is preferable to use alicyclic monocarboxylic acid or aromatic monocarboxylic acid for the λ / 4 retardation film according to the present invention in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-10. Use of acetic acid is preferred because of increased compatibility with cellulose acylate, and it is also preferred to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. The aromatic monocarboxylic acid which has, or those derivatives can be mentioned. In particular, benzoic acid is preferred.

  Although there is no restriction | limiting in particular in the molecular weight of a polyhydric alcohol ester, It is preferable that it is the range of molecular weight 300-1500, and it is further more preferable that it is the range of 350-750.

  A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with cellulose acetate.

  The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.

本発明において好ましいトリアジン環を有する化合物は、円盤状化合物であることがλ/４位相差フィルムの位相差を発現させ、かつ含水を低減する上で好ましい。分子量は、３００〜２，０００であることが好ましい。本発明において、円盤状化合物の沸点は、２６０℃以上であることが好ましい。沸点は、市販の測定装置（例えば、ＴＧ／ＤＴＡ１００、セイコー電子工業（株）製）を用いて測定できる。 Although the specific compound of a polyhydric alcohol ester is shown below, it is not limited to this.

The compound having a triazine ring preferable in the present invention is preferably a discotic compound from the viewpoint of expressing the retardation of the λ / 4 retardation film and reducing water content. The molecular weight is preferably 300 to 2,000. In the present invention, the boiling point of the discotic compound is preferably 260 ° C. or higher. The boiling point can be measured using a commercially available measuring device (for example, TG / DTA100, manufactured by Seiko Electronics Industry Co., Ltd.).

本発明に係るλ/４位相差フィルム、または後述する保護フィルムには、紫外線吸収剤を含有することが好ましく、用いられる紫外線吸収剤としては、ベンゾトリアゾール系紫外線吸収剤、２−ヒドロキシベンゾフェノン系紫外線吸収剤またはサリチル酸フェニルエステル系紫外線吸収剤等が挙げられる。例えば、２−（５−メチル−２−ヒドロキシフェニル）ベンゾトリアゾール、２−［２−ヒドロキシ−３，５−ビス（α，α−ジメチルベンジル）フェニル］−２Ｈ−ベンゾトリアゾール、２−（３，５−ジ−ｔ−ブチル−２−ヒドロキシフェニル）ベンゾトリアゾール等のトリアゾール類、２−ヒドロキシ−４−メトキシベンゾフェノン、２−ヒドロキシ−４−オクトキシベンゾフェノン、２，２′−ジヒドロキシ−４−メトキシベンゾフェノン等のベンゾフェノン類を例示することができる。 Specific examples of the compound having a triazine ring that can be suitably used in the present invention are shown below.

The λ / 4 retardation film according to the present invention or the protective film described later preferably contains an ultraviolet absorber. Examples of the ultraviolet absorber used include benzotriazole ultraviolet absorbers and 2-hydroxybenzophenone ultraviolet rays. Examples thereof include an absorber or a salicylic acid phenyl ester ultraviolet absorber. For example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3 Triazoles such as 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone And benzophenones.

  Among UV absorbers, UV absorbers with a molecular weight of 400 or more are difficult to volatilize at high boiling points and are difficult to disperse even during high temperature molding, so that the weather resistance can be effectively improved with a relatively small amount of addition. Can do.

  Examples of the ultraviolet absorber having a molecular weight of 400 or more include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- ( 1,1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] and the like, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, Hindered amines such as bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and further 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl Bis (1,2,2,6,6-pentamethyl-4-piperidyl) malonate, 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy Cis] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine The hybrid type | system | group which has the structure of a hindered amine is mentioned, These can be used individually or in combination of 2 or more types. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

  Commercially available products may be used. For example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, TINUVIN 328, and TINUVIN 928 manufactured by BASF Japan Ltd. can be preferably used.

  Furthermore, various antioxidants can be added to the λ / 4 retardation film in order to improve the thermal decomposability and thermal colorability during molding. An antistatic agent can be added to impart antistatic performance to the λ / 4 retardation film.

  For the λ / 4 retardation film according to the present invention, a flame retardant acrylic resin composition containing a phosphorus flame retardant may be used. Phosphorus flame retardants used here include red phosphorus, triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, aryl phosphonate compound, aryl phosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphorus. Examples thereof include one or a mixture of two or more selected from acid esters, halogen-containing condensed phosphates, halogen-containing condensed phosphonates, halogen-containing phosphites, and the like.

  Specific examples include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl). Examples thereof include phosphate and tris (tribromoneopentyl) phosphate.

  In addition, the λ / 4 retardation film according to the present invention has, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, and hydrated silica in order to improve handleability. It is preferable to contain a matting agent such as inorganic fine particles such as calcium acid, aluminum silicate, magnesium silicate, and calcium phosphate, and a crosslinked polymer. Among these, silicon dioxide is preferably used because it can reduce the haze of the film.

  The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

  The λ / 4 retardation film according to the present invention is required to withstand use in a higher temperature environment, and the tension softening point of the λ / 4 retardation film is 105 to 145 ° C. In order to show heat resistance, it is preferable, and 110 to 130 degreeC is especially preferable.

  As a specific method for measuring the tension softening point, for example, using a Tensilon tester (produced by ORIENTEC, RTC-1225A), a sample film is cut out at 120 mm (length) × 10 mm (width) and pulled with a tension of 10 N. However, the temperature can be continuously increased at a temperature increase rate of 30 ° C./min, and the temperature at 9 N can be measured three times, and the average value can be obtained.

  The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a temperature rising rate of 20 ° C./min. Point glass transition temperature (Tmg).

  When the λ / 4 retardation film according to the present invention is used in the organic EL display device of the present invention, in order not to cause problems such as unevenness, change in retardation value, decrease in contrast, and color unevenness due to dimensional change due to moisture absorption. The dimensional change rate (%) of the λ / 4 retardation film is preferably less than 0.5%, and more preferably less than 0.3%.

  The λ / 4 retardation film according to the present invention preferably has few defects in the film, where the defects are cavities in the film that are generated due to rapid evaporation of the solvent in the drying step of solution casting ( Foam defects) and foreign substances in the film (foreign substance defects) caused by foreign substances in the film-forming stock solution and foreign substances mixed in during film formation.

  Specifically, it is preferable that the number of defects having a diameter of 5 μm or more in the film plane is 1/10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, and particularly preferably 0.1 piece / 10 cm square or less.

  The diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope according to the following method, and is defined as the maximum diameter (diameter of circumscribed circle).

  The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion, the size is confirmed by observing the defect with the reflected light of a differential interference microscope.

  In addition, when observing with reflected light, if the size of the defect is unclear, aluminum or platinum is deposited on the surface for observation. In order to obtain a film having excellent quality expressed by such a defect frequency with high productivity, it is necessary to filter the polymer solution with high precision immediately before casting, to increase the cleanliness around the casting machine, It is effective to set drying conditions after rolling stepwise and to dry efficiently while suppressing foaming.

  When the number of defects is greater than 1/10 cm square, for example, when the film is tensioned during processing in a later process, the film may break with the defects as a starting point, and productivity may decrease. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

  Further, in the λ / 4 retardation film according to the present invention, the elongation at break in at least one direction is preferably 10% or more, more preferably 20% or more in the measurement based on JIS-K7127-1999. is there.

  The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming.

  The λ / 4 retardation film according to the present invention preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, as a realistic upper limit, it is about 99%. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film. Also, reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is effective to reduce the diffusion and reflection of light on the film surface.

<< Method for forming λ / 4 retardation film >>
Next, an example of a method for forming a λ / 4 retardation film according to the present invention will be described, but the present invention is not limited thereto.

  As a method for forming a λ / 4 retardation film according to the present invention, for example, a production method such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, or a hot press method can be used. .

  As a method for forming the λ / 4 retardation film according to the present invention, the solution casting method or the melt casting method may be used.

  The solution casting method is preferable from the viewpoints of suppressing coloring of the film, suppressing defects of foreign matters, and suppressing optical defects such as die lines. Moreover, the method of producing by a melt casting method is preferable from the viewpoint of suppressing the residual solvent used for dissolving cellulose acylate. Methods formed by melt casting can be classified into melt extrusion molding methods, press molding methods, inflation methods, injection molding methods, blow molding methods, stretch molding methods, and the like. Among these, the melt extrusion method is preferable, in which a film having excellent mechanical strength and surface accuracy can be obtained.

[Organic solvent]
When the λ / 4 retardation film according to the present invention is produced by the solution casting method, the organic solvent useful for forming the dope is limited as long as it can dissolve cellulose acylate and other additives simultaneously. Can be used.

  For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

  In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels, facilitating peeling from the metal support, and when the proportion of alcohol is small, the dissolution of cellulose acylate in a non-chlorine organic solvent system is promoted. There is also a role.

  In particular, in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, at least 15 to 45 total of at least three kinds of acrylic resin, cellulose ester resin, and acrylic particles are used. A dope composition dissolved in mass% is preferred.

  Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

[Solution casting method]
The λ / 4 retardation film according to the present invention can be produced by a solution casting method. In the solution casting method, a dope is prepared by dissolving a resin and an additive in an organic solvent, the dope is cast on a belt-shaped or drum-shaped metal support, and the cast dope is dried as a web. It is performed by a step, a step of peeling from a metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.

  The concentration of cellulose acylate in the dope is preferably higher because the drying load after casting on a metal support can be reduced. However, if the concentration of cellulose acetate is too high, the load during filtration increases and filtration is performed. The accuracy becomes worse. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%. The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.

  The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting process is set to −50 ° C. to a temperature at which the organic solvent boils and does not foam. A higher temperature is preferable because the web can be dried faster, but if it is too high, the web may foam and flatness may deteriorate.

  A preferable temperature of the metal support is appropriately determined in the range of 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

  When using hot air, considering the temperature drop of the web due to the latent heat of evaporation of the organic solvent, use hot air that is higher than the boiling point of the organic solvent, and use air at a temperature higher than the target temperature while preventing foaming. There is.

  In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In order for the λ / 4 retardation film to exhibit good planarity, the amount of residual solvent when peeling the web from the metal support is preferably in the range of 10 to 150% by mass, more preferably 20 to 40%. It is 20 mass% or 60-130 mass%, Most preferably, it is 20-30 mass% or 70-120 mass%.

  The residual solvent amount referred to in the present invention is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected at any time during or after production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Further, in the drying step of the λ / 4 retardation film, the web is peeled off from the metal support, and further dried, so that the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less. And particularly preferably 0 to 0.01% by mass or less.

  In the film drying step, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

[Stretching process]
In the λ / 4 retardation film according to the present invention, the retardation Ro (550) in the in-plane direction measured at a wavelength of 550 nm is preferably in the range of 100 to 180 nm. The retardation Ro is preferably applied by film stretching.

  There is no particular limitation on the stretching method. For example, a method in which a difference in peripheral speed is applied to a plurality of rolls, and the roll peripheral speed difference is used to stretch in the longitudinal direction between the rolls. And a method of stretching in the vertical direction, a method of stretching in the horizontal direction and stretching in the horizontal direction, a method of stretching in the vertical and horizontal directions and stretching in both the vertical and horizontal directions, and the like. Of course, you may use combining these methods suitably. That is, the film may be stretched in the transverse direction, longitudinally, or in both directions with respect to the film forming direction. Further, when stretching in both directions, simultaneous stretching or sequential stretching may be used. May be. In the case of the so-called tenter method, driving the clip portion by the linear drive method is preferable in that smooth stretching can be performed and the risk of breakage and the like can be reduced.

  In the present invention, in particular, the stretching method is performed in the transport direction by utilizing the peripheral speed difference of the film transport roll, or the both ends of the web are clipped in the direction perpendicular to the transport direction (also referred to as the width direction or the TD direction). It is preferable to use a tenter system that grips the web with a right and left gripping means, and it is also preferable to use a tenter that can independently control the web gripping length (distance from the start of gripping to the end of gripping) with the left and right gripping means.

  In addition, it is preferable to stretch the λ / 4 retardation film according to the present invention in the stretching process in a 45 ° direction with respect to the film conveyance direction from the viewpoint of efficiently producing the λ / 4 retardation film.

  As described above, a roll-shaped polarizing film having a transmission axis in a direction parallel to the longitudinal direction of the slow axis and a λ / 4 retardation film having an orientation angle of substantially 45 ° are aligned with each other in the longitudinal direction. When pasted with a to-roll, a roll-like long circularly polarizing plate can be easily produced, which is advantageous in production with less film cut loss.

  Hereinafter, a specific method of stretching in the 45 ° direction will be described.

  In the production process of the λ / 4 retardation film according to the present invention, it is preferable to use an obliquely stretched tenter in order to impart an oblique orientation to a long continuous film film subjected to stretching. The diagonally stretched tenter can change the orientation angle of the film by changing the rail pattern in various ways.In addition, the orientation axis of the film can be oriented with high accuracy evenly on the left and right across the film width direction. And it is preferable that it is a film extending apparatus which can control film thickness and retardation with high precision.

  FIG. 2 is a schematic diagram of a tenter that can be stretched obliquely and can be used for manufacturing a λ / 4 retardation film according to the present invention. However, this is an example, and the present invention is not limited to this.

  In the tenter structure 1 that can be stretched obliquely shown in FIG. 2 (a), the long film original fabric 4 whose direction is controlled by the guide roll 12-1 on the tenter entrance side is the outer film holding start point 8-1, It is carried by a gripping tool (also referred to as a clip gripping portion) at the position of the inner film holding start point 8-2, and is trajectory 7-1 of the outer film holding means, and the trajectory 7 of the inner film holding means by the oblique stretching tenter 6. -2 is conveyed and stretched in an oblique direction indicated by -2, is released by the outer film holding end point 9-1 and the inner film holding end point 9-2, and is conveyed by the guide roll 12-2 on the tenter outlet side. The obliquely stretched film 5 is formed by being controlled. In the drawing, the long film original is obliquely stretched at an angle (feeding angle θi) in the film stretching direction 14-2 with respect to the film feeding direction 14-1.

  FIG. 2B shows another tenter structure 2 that can be obliquely stretched. The tenter structure 1 that can be obliquely stretched shown in FIG. 2A can be stretched.

  Stretching in the production process of the λ / 4 retardation film according to the present invention is performed using the tenter capable of oblique stretching. This tenter is an apparatus that widens a long film original fabric in an oblique direction with respect to its traveling direction (moving direction of the middle point in the film width direction) in an environment heated by an oven. The tenter includes an oven, a pair of rails on the left and right on which a gripping tool for transporting the film travels, and a number of gripping tools that travel on the rails. Both ends of the film fed out from the film roll and sequentially supplied to the entrance portion of the tenter are gripped by a gripping tool, the film is guided into the oven, and the film is released from the gripping tool at the exit portion of the tenter. The film released from the gripping tool is wound around the core. Each of the pair of rails has an endless continuous track, and the gripping tool which has released the grip of the film at the exit portion of the tenter travels outside and is sequentially returned to the entrance portion.

  As shown in FIGS. 2 (a) and 2 (b), the rail shape of the tenter has an asymmetric shape on the left and right depending on the orientation angle θ, the draw ratio, and the like given to the long stretched film to be manufactured. It can be fine-tuned manually or automatically. In the present invention, a long thermoplastic resin film is stretched, and the orientation angle θ can be set to an arbitrary angle within a range of preferably 10 ° to 80 ° with respect to the winding direction after stretching. ing.

  Although the traveling speed of a holding | gripping tool can be selected suitably, it is 1-100 m / min normally. The difference in travel speed between the pair of left and right grippers is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed between the left and right sides of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the right and left gripping tools is required to be substantially the same speed. Because. In general tenter devices, etc., there are speed irregularities that occur in the order of seconds or less depending on the period of the sprocket teeth driving the chain, the frequency of the drive motor, etc. It does not fall under the difference.

  Moreover, in the diagonally stretched tenter used in the present invention, it is preferable that the positions of the rail portions and the rail connecting portions can be freely set. Therefore, the oblique stretching tenter can be set to a stretching ratio according to an arbitrary entrance width and exit width. (In the figure, the part indicated by “◯” is a connecting part).

  In the obliquely stretched tenter used in the present invention, a large bending rate is often required for the rail that regulates the locus of the gripping tool. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws an arc at the bent portion.

  In the oblique stretching tenter shown in FIG. 2A, the traveling direction 14-1 at the tenter entrance of the long film original is different from the traveling direction 14-2 at the tenter exit side of the stretched film. Yes. The feeding angle θi is an angle formed by the traveling direction 14-1 at the tenter inlet and the traveling direction 14-2 on the tenter exit side of the stretched film.

  In the obliquely stretched tenter shown in FIG. 2B, the traveling direction 14-1 at the tenter inlet of the long film original is different from the traveling direction at the tenter inlet at the feeding angle θi in the tenter. To be transported. Thereafter, the transport direction is further changed, and finally, a trajectory that matches the traveling direction on the tenter exit side of the stretched film is taken.

  In the present invention, in order to produce a film having an orientation angle θ of preferably 10 ° to 80 ° as described above, the feeding angle θi is 10 ° <θi <60 °, preferably 15 ° <θi <50 °. Set by. By setting the feeding angle θi in the above range, the variation in the optical characteristics in the width direction of the obtained film becomes good (smaller).

  In the present invention, the gripping tool of the tenter is configured to travel at a constant speed with a certain distance from the front and rear gripping tools.

  (A-2) and (b-2) in FIG. 3 schematically show the stretching direction in the oblique stretching tenter shown in (a) and (b) of FIG.

  In the present invention, as shown by (a-2) and (b-2) in FIG. 3, the both ends of the transport film are gripped by the gripping tool for the first time, that is, the transport on the introduction side from the grip start points A1 and A1. Starting from two points B1 (that is, the film grip start point on the opposite side) where the straight line drawn substantially perpendicular to the center line of the film intersects the trajectory of the opposite gripping means, the gripping tools at both ends are substantially constant. When transported at a speed, the stretching end point An moves from A1 to A2 and A3 every unit time, and B1 similarly travels from B1 to B2 and B3 to the stretching end point Bn. By using such a stretching method, as shown in (a-2) and (b-2) of FIG. 3, the gripping portion An is gradually delayed with respect to Bn, so the stretching direction is the width direction. It gradually tilts from. The actual grip end point (the point at which the gripped transport film is released from the gripper that was gripped) is the point at which either or both ends of the transport film are released from the gripper, that is, the grip end A point Bx and a straight line drawn substantially perpendicularly to the center line of the transport film sent from Bx to the next process are defined by two points Ay that intersect with the trajectory of the gripping means on the opposite side. Here, “substantially vertical” means within 90 ± 1 °.

  The angle in the final film stretching direction is determined by the distance W between the grip end points (the distance between Bx and Ay) and the ratio between Ax and Ay.

Therefore, the inclination angle θf formed by the stretching direction with respect to the transport direction to the next direction is
tan θf = W / (Ay−Ax)
That is,
tan θf = W / | LA-LB |
An angle that satisfies

  Here, LA is the travel distance from the grip start point to the grip end point on the tenter rail on the large turn side, and LB is the grip point from the grip start point to the grip end point on the small tenter rail path. | LA-LB | is the difference in distance that the left and right grippers travel on the tenter rail at the grip end point.

  The definition of the draw ratio in the present invention will be described with reference to FIG.

In FIG. 3, the linear distance from the grip start point A1 to B1 where the transport film is gripped for the first time by the gripping tool in the oblique stretching tenter is Lo, and both of the gripping tools have passed through all stretching zones in the oblique stretching tenter. When the gripping tool position (stretching end point) is An and Bn, and the linear distance between An and Bn is L, the stretching ratio R in the oblique stretching tenter is
R = L / L0
Defined by

  The draw ratio R at this time is preferably 1.3 to 3.0, more preferably 1.5 to 2.5. If the draw ratio is in this range, thickness unevenness in the width direction is reduced, which is preferable. In the stretching zone of the oblique stretching tenter, if the stretching temperature is differentiated in the width direction, the thickness unevenness in the width direction can be further improved.

  In the obliquely stretched tenter, as shown in FIG. 2, the long film original is sequentially held at both ends (both sides) by the right and left gripping tools at the tenter entrance (position a). Traveled with the travel. At the tenter entrance (position a), the left and right gripping tools facing the direction substantially perpendicular to the film traveling direction (14-1) run on the left-right asymmetric rail, preheating zone, and lateral stretching. It passes through an oven having a zone, an oblique stretching zone, a holding zone, and a cooling zone.

  However, it is not always necessary to transport the film in all the above zones in the above order. For example, as shown in the following combination example, only a part of the above zones may be used, or any of the above zones may be used several times. Or you may.

1) Preheating zone / oblique stretching zone / holding zone / cooling zone 2) Preheating zone / lateral stretching zone / oblique stretching zone / holding zone / cooling zone 3) Preheating zone / oblique stretching zone / lateral stretching zone / holding zone / cooling zone 4) Preheating zone / transverse stretching zone 1 / oblique stretching zone / transverse stretching zone 2 / holding zone / cooling zone 5) Preheating zone / transverse stretching zone 1 / oblique stretching zone 1 / transverse stretching zone 2 / oblique stretching zone 2 / holding Zone / Cooling Zone The preheating zone refers to a section where the distance between the gripping tools gripping both ends of the film is kept constant at the oven entrance.

  The transverse stretching zone refers to a section where the gap between the gripping tools gripping both ends of the film starts to reach a predetermined interval. At this time, the opening angle of the rail on which the gripping tools at both ends run may be opened at the same angle for both rails, or may be opened at different angles.

  The diagonally stretched zone refers to a gripping tool that grips both ends of the film, while the gripping tool spacing is kept constant or spreads, and then both gripping tools travel on the straight rail again after starting to run on the bending rail. Refers to the section until the beginning.

  The holding zone refers to a section in which the gripping tools at both ends travel while being parallel to each other in a period in which the interval between the gripping tools after the transverse stretching zone or the oblique stretching zone becomes constant again.

  The cooling zone refers to a section where the temperature in the zone is set to be equal to or lower than the glass transition temperature Tg ° C. of the thermoplastic resin constituting the film in the section after the holding zone.

  At this time, in consideration of shrinkage of the film due to cooling, a rail pattern that narrows the gap between the opposing grippers in advance may be used.

  The temperature of each zone is set to Tg to Tg + 30 ° C., the temperature of the stretching zone is set to Tg to Tg + 30 ° C., and the temperature of the cooling zone is set to Tg−30 to Tg ° C. with respect to the glass transition temperature Tg of the thermoplastic resin. It is preferable to do.

  In order to control the thickness unevenness in the width direction, a temperature difference may be applied in the width direction in the stretching zone. Examples of a method of imparting a temperature difference in the width direction in the stretching zone include, for example, a method of adjusting the opening degree of the nozzle that sends warm air into the temperature-controlled room so as to make a difference in the width direction, and heating by arranging heaters in the width direction. A known method such as control can be used.

  Furthermore, as a method for preventing the occurrence of wrinkles and shifts in a long stretched film, the film is maintained while supporting the film at the time of stretching, stretched in the state where the volatile content is 5% by volume or more, and then volatilized while shrinking. The method etc. which reduce a fraction can be mentioned. Maintaining the supportability of the film as used in the present invention means holding both side edges without impairing the film properties of the film. As for the volatile content, the state of 5% by volume or more may always be maintained in the stretching operation process, and the state of the volatile content is maintained at 5% by volume or more only in a part of the stretching operation process. May be. In the latter case, it is preferable that the entrance position is a starting point, and that the section of 50% or more of the entire stretching section and the volatile content rate are 12% by volume or more. In any case, it is preferable to have a volatile content of 12% by volume or more before stretching. Here, the volatile fraction (unit: volume%) represents the volume of the volatile component contained per unit volume of the film, and is a value obtained by dividing the volatile component volume by the film volume.

  The guide roll closest to the entrance of the tenter is a follower roll that guides the traveling of the film, and is rotatably supported by bearings via bearings. Known materials can be used for the roll, but it is preferable to reduce the weight, such as a method of applying a ceramic coat to prevent the film from being damaged, a method of applying chrome plating to a light metal such as aluminum, and the like. . This roll is provided in order to stabilize the track when the film travels.

  Moreover, it is preferable that one of the rolls on the upstream side of the roll is nipped by pressing the rubber roll. This is because such a nip roll can suppress fluctuations in the drawing tension in the film flow direction.

  A pair of bearing portions at both ends (left and right) of the guide roll closest to the entrance of the tenter are provided with a first tension detecting device and a second film tension detecting device for detecting the tension generated in the film in the roll. It has been. For example, a load cell can be used as the film tension detection device. As the load cell, a known tensile or compression type can be used. A load cell is a device that detects a load acting on an applied point by converting it into an electrical signal using a strain gauge attached to the strain generating body.

  The load cell is installed on the left and right bearings of the guide roll closest to the entrance of the diagonally stretched tenter, so that the force that the running film exerts on the roll, that is, the tension in the film traveling direction that is generated near both side edges of the film Are detected independently on the left and right. In addition, a strain gauge may be directly attached to a support that constitutes the bearing portion of the roll, and a load, that is, a film tension may be detected based on the strain generated in the support. The relationship between the generated strain and the film tension is measured in advance and is known.

  The film tension detection device as described above is provided so that the tension in the vicinity of both side edges of the film in the guide roll closest to the entrance of the oblique stretching tenter is detected because the position and direction of the film is the same as that of the film stretching device. If there is a deviation with respect to the position and direction of the entrance, depending on the amount of deviation, there will be a difference in the tension in the vicinity of both side edges of the film in the guide roll closest to the entrance of the obliquely stretched tenter. This is because the degree of deviation is determined by detecting this tension difference. If the position and direction of the film are appropriate in relation to the position and direction of the inlet portion of the film stretching apparatus, the load acting on the roll will be roughly equal on the left and right, and if the positions are misaligned, the left and right films There is a difference in tension.

  Therefore, if the film position and angle are adjusted appropriately so that the difference in film tension between the left and right sides of the guide roll closest to the entrance of the oblique stretching tenter is equal, gripping by the gripping tool at the entrance of the film stretching apparatus is stable. In addition, the occurrence of obstacles such as removal of the gripping tool can be reduced. Furthermore, the physical properties in the width direction of the film after oblique stretching by the film stretching apparatus can be stabilized.

  In order to cope with fine adjustment of the orientation angle and product variations, it is necessary to adjust the angle formed by the film traveling direction at the entrance of the oblique stretching tenter and the film traveling direction at the exit of the oblique stretching tenter. In that case, it is preferable from a viewpoint of productivity or a yield to perform film forming and diagonal stretch continuously. When the film forming process, the oblique stretching process, and the winding process are successively performed, it is preferable that the film traveling direction in the film forming process and the winding process coincide with each other in that the width of the process can be reduced. For such a process, in order to change the film transport direction to guide the formed film to the oblique stretching tenter inlet and / or to return the film exiting the oblique stretching tenter outlet to the winding device direction. A method for changing the film transport direction is required. As a device for changing the film transport direction, a known method such as an air flow roll can be used. It is preferable that a device (winding device, accumulator device, drive device, etc.) after the obliquely extending tenter exit is slidable in the lateral direction.

  Next, a method for producing a λ / 4 retardation film according to the present invention will be described with reference to the drawings.

In Figure 4 (a) ~ (c) is a schematic diagram showing an example of an manufacturing method of the present invention (an example of oblique stretching from feeding an elongated film master roll).

In FIG. 5 (a), (b) is a schematic diagram showing an example of an manufacturing method of the present invention (an example of continuously oblique stretching without winding the long raw film material).

(A) ~ in FIG. 4 (c) shows an example of a pattern that obliquely extending feed each once long film raw fabric wound in a roll, in FIG. 5 (a), (b) These show an example of the pattern which performs a diagonal stretch process continuously, without winding up a respectively long film original fabric.

  In FIG. 4, 16 is a film feeding device, 17 is a conveying direction changing device, 18 is a winding device, and 19 is a film forming device. In each figure, symbols indicating the same thing may be omitted.

  The film feeding device 16 is slidable and pivotable so that the film can be fed at a predetermined angle with respect to the entrance of the oblique stretching tenter, or the film feeding device 16 is slidable, and the transport direction changing device 17 It is preferable that the film can be sent out to the entrance of the obliquely stretched tenter. By configuring the film feeding device 16 and the conveyance direction changing device 17 in such a configuration, the width of the entire manufacturing apparatus can be further reduced, and the film feeding position and angle can be finely controlled. This makes it possible to obtain a stretched film having small variations in film thickness and optical value. In addition, by making the film feeding device 16 and the conveyance direction changing device 17 movable, it is possible to effectively prevent the left and right clips from being caught in the film.

  By forming the winding device 18 so that the film can be pulled at a predetermined angle with respect to the outlet of the obliquely stretched tenter, it is possible to finely control the film take-up position and angle, and there are variations in film thickness and optical value. A small stretched film can be obtained. Therefore, the generation of wrinkles in the film can be effectively prevented, and the winding property of the film is improved, so that the film can be wound up in a long length. In the present invention, the take-up tension T (N / m) of the stretched film needs to be adjusted between 100 N / m <T <300 N / m, preferably 150 N / m <T <250 N / m.

  When the take-up tension is 100 N / m or less, sagging and wrinkles of the film are likely to occur, and the retardation and the profile in the width direction of the orientation axis are also deteriorated. On the other hand, when the take-up tension is 300 N / m or more, the variation in the orientation angle in the width direction is deteriorated, and the width yield (taking efficiency in the width direction) is deteriorated.

  In the present invention, it is necessary to control the fluctuation of the take-up tension T with an accuracy of less than ± 5%, preferably less than ± 3%. When the fluctuation of the take-up tension T is ± 5% or more, the variation in the optical characteristics in the width direction and the flow direction becomes large. As a method for controlling the fluctuation of the take-up tension T within the above range, general PID control is performed so that the load applied to the first roll at the tenter outlet, that is, the film tension is measured and the value is kept constant. Examples include a method of controlling the rotation speed of the take-up roll by a method (P (proportional control), I (integral control), D (differential control)). Examples of the method for measuring the load include a method in which a load cell is attached to a bearing portion of a roll and a load applied to the roll, that is, a film tension is measured. As the load cell, a known tensile type or compression type can be used.

  The stretched film is released from the tenter outlet after being gripped by the gripper, trimmed at both ends (both sides) of the film, and then wound around a winding core (winding roll) to wind the stretched film. It can be turned around.

  Moreover, you may trim the both ends of the film currently hold | gripped with the holding tool of a tenter before winding up to a winding roll as needed. In addition, before winding, for the purpose of preventing blocking between the films, the masking film may be overlapped and wound up at the same time, or at least one of the stretched films, preferably wound up with tape or the like attached to both ends. Also good. The masking film is not particularly limited as long as it can protect the film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

  The stretched film obtained by the above production method has an orientation angle θ inclined in the range of, for example, 10 ° to 80 ° with respect to the winding direction, and is an in-plane litter in the width direction at a width of at least 1300 mm. It is preferable that the variation in the foundation Ro is 4 nm or less and the variation in the orientation angle θ is 1.0 ° or less.

  In the present invention, the variation of the in-plane retardation Ro of the stretched film is 4 nm or less, preferably 3 nm or less, in at least 1300 mm in the width direction. By setting the variation of the in-plane retardation Ro within the above range, the display quality can be improved when used as a retardation film for a liquid crystal display device.

  In the present invention, the variation in the orientation angle θ of the stretched film is 1.0 ° or less, preferably 0.80 ° or less, in at least 1300 mm in the width direction. When a stretched film having a variation in the orientation angle θ exceeding 1.0 ° is bonded to a polarizer to obtain a circularly polarizing plate and this is installed in a liquid crystal display device, light leakage may occur and the contrast may be lowered.

  The optimum value of the in-plane retardation Ro of the stretched film of the present invention is selected depending on the design of the display device used. Note that Ro is a value obtained by multiplying the difference between the refractive index nx in the in-plane slow axis direction and the refractive index ny in the direction perpendicular to the slow axis by the average thickness d of the film (Ro = (nx −ny) × d).

  The average thickness of the stretched film of the present invention is preferably 20 to 80 μm, more preferably 30 to 60 μm, and particularly preferably 30 to 40 μm from the viewpoint of mechanical strength and the like.

  Moreover, since the thickness unevenness in the width direction affects the availability of winding, it is preferably 3 μm or less, and more preferably 2 μm or less.

[Melting method]
The λ / 4 retardation film according to the present invention may be formed by a melt film forming method. The melt film-forming method refers to heating and melting a composition containing an additive such as a resin and a plasticizer to a temperature exhibiting fluidity, and then casting a melt containing fluid cellulose acetate.

  More specifically, the heat melting molding method can be classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these molding methods, the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy. It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded in advance and pelletized.

  Pelletization may be performed by a known method. For example, dry cellulose acetate, a plasticizer, and other additives are fed to an extruder with a feeder and kneaded using a single-screw or twin-screw extruder, and formed into a strand form from a die. It can be done by extrusion, water cooling or air cooling and cutting.

  The additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

  A small amount of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.

  The extruder is preferably processed at as low a temperature as possible so as to be able to be pelletized so that the shear force is suppressed and the resin does not deteriorate (decrease in molecular weight, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

  A film is formed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

  The melting temperature when extruding the pellets using a single-screw or twin-screw type extruder is about 200 to 300 ° C., filtered through a leaf disk type filter or the like to remove foreign matters, and then formed into a film from a T die. The film is cast and the film is nipped by a cooling roll and an elastic touch roll, and solidified on the cooling roll.

  When introducing from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like under vacuum, reduced pressure, or inert gas atmosphere.

  The extrusion flow rate is preferably performed stably by introducing a gear pump or the like. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances. The stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated. The density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.

  Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

  The film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll is preferably Tg or more and Tg + 110 ° C. or less of the film. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.

  The elastic touch roll is also called a pinching rotator. As the elastic touch roll, a commercially available one can be used.

  When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.

  Moreover, it is preferable that the film obtained as described above is stretched by the stretching operation after passing through the step of contacting the cooling roll.

  As a method of stretching, a known roll stretching machine or tenter can be preferably used. The stretching temperature is usually preferably performed in the temperature range of Tg to Tg + 60 ° C. of the resin constituting the film.

  Prior to winding, the ends may be slit and cut to the width of the product, and knurling (embossing) may be applied to both ends to prevent sticking or scratching during winding. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing. In addition, since the film has deform | transformed and cannot use as a product normally, the holding | grip part of the clip of both ends of a film is cut out and reused.

[Physical properties of λ / 4 retardation film]
The film thickness of the λ / 4 retardation film according to the present invention is not particularly limited, but is used in the range of 10 to 250 μm. Furthermore, the film thickness is preferably in the range of 10 to 100 μm, particularly preferably 30 to 60 μm.

  The λ / 4 retardation film according to the present invention has a width of 1 to 4 m. Furthermore, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.6 to 3 m. If it exceeds 4 m, conveyance becomes difficult.

  The arithmetic average roughness Ra of the surface of the λ / 4 retardation film according to the present invention is preferably 2.0 to 4.0 nm, more preferably 2.5 to 3.5 nm.

〔Protective film〕
The protective film according to the present invention (110 shown in FIG. 1) is preferably a protective film, such as a triacetyl cellulose film, a cellulose acetate propionate film, a cellulose diacetate film, and a cellulose acetate butyrate film. Cellulose ester film, polyester film such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, Polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, norbornene Fat-based film, polymethyl pentene film, polyether ketone film, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, cycloolefin polymer films, and polymethyl methacrylate film or an acrylic film or the like.

  Among these, cellulose ester films (for example, Konica Minoltak KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC4UE, KC4UA, KC6UA, and KC12UR (nor, Konica Minoru) A polycarbonate film, a cycloolefin polymer film, and a polyester film are preferable. In the present invention, a cellulose ester film is preferable from the viewpoints of optical properties, productivity, and cost.

  In the case of producing an organic EL display device for 3D (stereoscopic) image display, since a λ / 4 retardation film has an effect on improving the quality of a display image on both sides of a polarizer, a protective film It is also preferable to use the λ / 4 retardation film according to the present invention. In that case, the direction in which the maximum elastic modulus in the surface of the protective film is preferably in the direction of 35 ° to 55 ° with respect to the longitudinal direction of the screen of the image display device, and the in-plane of the λ / 4 retardation film By making it parallel to the direction of the maximum elastic modulus, there is no panel deflection, and a high-quality organic electroluminescence display device for 3D image display can be obtained.

(Surface antireflection layer)
It is also preferable to provide a surface antireflection layer (11 shown in FIG. 1) directly or via another layer on the protective film of the circularly polarizing plate to provide an antireflection layer having an external light antireflection function. .

  The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is preferably composed of a low refractive index layer having a refractive index lower than that of the support, or a combination of a high refractive index layer having a refractive index higher than that of the support and a low refractive index layer. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers, and three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support). Are preferably laminated in the order of a layer having a lower refractive index) / a high refractive index layer / a low refractive index layer. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used. Although the following structure can be considered as a structure of an antireflection layer, it is not limited to this.

Protective film / Low refractive index layer Protective film / Medium refractive index layer / Low refractive index layer Protective film / Medium refractive index layer / High refractive index layer / Low refractive index layer Protective film / High refractive index layer (conductive layer) / Low Refractive index layer (low refractive index layer)
In the antireflection layer, the low refractive index layer is an essential constituent element, but preferably contains silica-based fine particles, and the refractive index is lower than the refractive index of the base film as a support, 23 ° C., wavelength 550 nm. It is preferable that it is the range of 1.30-1.45 by measurement.

  The film thickness of the low refractive index layer is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and most preferably 30 nm to 0.2 μm.

  The composition for forming a low refractive index layer preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and having a porous or hollow interior are preferably hollow silica-based fine particles.

  The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.

General formula (OSi-1)
Si (OR) ₄
In the organosilicon compound represented by the general formula (OSi-1), R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  In addition, a silane coupling agent, a curing agent, a surfactant and the like may be added as necessary.

(High refractive index layer)
As a refractive index of a high refractive index layer, it is preferable to adjust a refractive index in the range of 1.4-2.2 by the measurement on conditions of 23 degreeC and wavelength 550nm. The thickness of the high refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The means for adjusting the refractive index can be achieved by adding metal oxide fine particles and the like. Metal oxide The metal oxide fine particles used preferably have a refractive index of 1.80 to 2.60, more preferably 1.85 to 2.50.

  The type of metal oxide fine particles applicable to the formation of the high refractive index layer is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, A metal oxide having at least one metal element selected from Zn, Al, Mg, Si, P and S can be used. These metal oxide fine particles have a particle surface of Al, In, Sn, Sb. , Nb, a halogen element, Ta, or a small amount of atoms may be doped. A mixture of these may also be used. In the present invention, at least one metal oxide fine particle selected from among zirconium oxide, antimony oxide, tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-doped tin oxide (ATO), and zinc antimonate is used. It is particularly preferable to use it as the main component. Among them, it is particularly preferable to contain zinc antimonate particles.

  The average particle diameter of the primary particles of these metal oxide fine particles is in the range of 10 nm to 200 nm, and more preferably 10 to 150 nm. The average particle diameter of the metal oxide fine particles can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. Further, it may be measured by a particle size distribution meter using a dynamic light scattering method or a static light scattering method. However, when the average particle size is less than 10 nm, aggregation tends to occur and the dispersibility deteriorates. On the other hand, if the average particle diameter exceeds 200 nm, the haze increases remarkably. The shape of the metal oxide fine particles is preferably an ellipse, a sphere, a cube, a spindle, a needle or an indefinite shape.

  The metal oxide fine particles may be surface-treated with an organic compound. By modifying the surface of the metal oxide fine particles with an organic compound, the dispersion stability in an organic solvent is improved, the dispersion particle size can be easily controlled, and aggregation and sedimentation over time can be suppressed. . For this reason, the surface modification amount with a preferable organic compound is 0.1 mass%-5 mass% with respect to metal oxide particle, More preferably, it is 0.5 mass%-3 mass%.

  Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Of these, silane coupling agents are preferred. Two or more kinds of surface treatments may be combined.

  The high refractive index layer may contain a π-conjugated conductive polymer. As the π-conjugated conductive polymer, any organic polymer whose main chain is composed of a π-conjugated system can be used. Examples thereof include polythiophenes, polypyrroles, polyanilines, polyphenylenes, polyacetylenes, polyphenylene vinylenes, polyacenes, polythiophene vinylenes, and copolymers thereof. From the viewpoint of ease of polymerization and stability, polythiophenes, polyanilines, and polyacetylenes are preferable.

The π-conjugated conductive polymer can provide sufficient conductivity and solubility in a binder resin even if it is not substituted, but in order to further improve conductivity and solubility, an alkyl group, a carboxy group, a sulfo group, an alkoxy group. A functional group such as a group, a hydroxy group, or a cyano group may be introduced. Moreover, you may contain an ionic compound. The ionic compounds, imidazolium, pyridinium-based, alicyclic amine-based, aliphatic amine, cations and _BF ⁴ aliphatic phosphonium -, PF ₆ ^- inorganic ion system such, _CF 3 SO ₂ ^- , (CF ₃ SO ₂ ) ₂ N ⁻ , CF ₃ CO ₂ ^—, etc. The ratio of the polymer to the binder is preferably 10 to 400 parts by mass of the binder with respect to 100 parts by mass of the polymer, and particularly preferably 100 to 200 parts by mass of the binder with respect to 100 parts by mass of the polymer.

[Polarizer]
As the polarizer constituting the organic EL display device of the present invention shown in FIG. 1, any appropriate polarizer can be adopted depending on the purpose. For example, a dichroic substance such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film or an ethylene / vinyl acetate copolymer partially saponified film. Examples include uniaxially stretched films, polyene-based oriented films such as polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polyvinyl alcohol film and uniaxially stretching is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 1 to 80 μm.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film can be produced by, for example, dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  By washing the polyvinyl alcohol film with water, not only can the surface of the polyvinyl alcohol film be cleaned and the anti-blocking agent can be washed, but also the effect of preventing unevenness such as uneven dyeing can be obtained by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

《Organic electroluminescence device》
Next, each component of the organic EL element constituting the organic EL display device of the present invention will be described.

  As shown in FIG. 1, the organic EL element B according to the present invention includes, for example, a metal electrode 102, an organic light emitting layer 103, a transparent electrode (ITO, etc.) 104, an insulating layer on a substrate 101 using glass, polyimide, or the like. Specifically, the organic light-emitting layer 104 includes, for example, a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport. It is the structure which laminated | stacked the layer.

〔substrate〕
The substrate 101 that can be used in the organic EL display device shown in FIG. 1 is not particularly limited in the type such as glass and plastic, and may be transparent or opaque. When light is extracted from the substrate 1 side, the substrate 1 is preferably transparent. Examples of the transparent substrate preferably used include glass, quartz, and a transparent resin film.

(Resin film)
Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24h · atm) or less, and further measured by a method according to JIS K 7126-1987. A high barrier film having an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 1 × 10 ⁻⁵ g / (m ² · 24 h · atm) or less. Preferably there is.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque substrate include a metal plate such as aluminum and stainless steel, a film, an opaque resin substrate, a ceramic substrate, and the like.

(Glass plate)
The substrate is preferably a glass plate from the viewpoint of preventing warpage of the organic electroluminescence display device. The thickness of the glass plate is preferably from 0.1 mm to 10 mm. If it is 0.1 mm or more, the durability is good, it is not cracked by a weak impact during transportation or use, and it is not warped even when heated, and the visibility is not deteriorated by cracking. Moreover, if it is 10 mm or less, the weight of an organic electroluminescent display apparatus can be made light and manufacturing cost can also be held down.

[Metal electrode]
A metal electrode (also referred to as an anode) has a high work function from the vacuum level of the electrode material in order to inject holes efficiently, such as aluminum (Al), chromium (Cr), molybdenum (Mo), Tungsten (W), copper (Cu), silver (Ag), gold (Au) metals and alloys thereof, oxides of these metals and alloys, or tin oxide (SnO ₂ ) and antimony (Sb) Alloy, ITO (indium tin oxide), InZnO (indium zinc oxide), alloy of zinc oxide (ZnO) and aluminum (Al), and oxides of these metals and alloys alone or mixed Used in

  In addition, the anode may have a laminated structure of a first layer having excellent light reflectivity and a second layer having a light transmission property and a large work function provided thereon.

  For example, the first layer is made of an alloy containing aluminum as a main component. The subcomponent may include at least one element having a work function relatively smaller than that of aluminum as a main component. As such a subcomponent, a lanthanoid series element is preferable. Although the work function of the lanthanoid series elements is not large, the inclusion of these elements improves the stability of the anode and also satisfies the hole injection property of the anode. In addition to lanthanoid series elements, elements such as silicon (Si) and copper (Cu) may be included as subcomponents.

  The content of subcomponents in the aluminum alloy layer constituting the first layer is preferably about 10% by mass or less in total if it is Nd, Ni, Ti, or the like that stabilizes aluminum. Thereby, while maintaining the reflectance in the aluminum alloy layer, the aluminum alloy layer can be stably maintained in the manufacturing process of the organic electroluminescent element, and further, processing accuracy and chemical stability can be obtained. In addition, the conductivity of the anode 23 and the adhesion to the substrate 22 can be improved.

  Examples of the second layer include a layer made of at least one of an oxide of an aluminum alloy, an oxide of molybdenum, an oxide of zirconium, an oxide of chromium, and an oxide of tantalum. Here, for example, when the second layer is an oxide layer of an aluminum alloy containing a lanthanoid element as a subcomponent (including a natural oxide film), the oxide of the lanthanoid element has a high transmittance, so that this is included. The transmittance of the second layer is improved. For this reason, it is possible to maintain a high reflectance on the surface of the first layer. Further, the second layer may be a transparent conductive layer such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). These conductive layers can improve the electron injection characteristics of the anode.

  The anode may be provided with a conductive layer for improving the adhesion between the anode and the transparent substrate on the side in contact with the substrate. Examples of such a conductive layer include transparent conductive layers such as ITO and IZO.

(Organic light emitting layer)
(Hole injection layer / hole transport layer)
The hole injection layer and the hole transport layer are for increasing the efficiency of hole injection into the light emitting layer. Examples of the material for the hole injection layer or the hole transport layer include benzine, styrylamine, triphenylamine, porphyrin, triphenylene, azatriphenylene, tetracyanoquinodimethane, triazole, imidazole, oxadiazole, poly Heterocyclic conjugated monomers such as arylalkanes, phenylenediamines, arylamines, oxazoles, anthracenes, fluorenones, hydrazones, stilbenes or their derivatives, or polysilane compounds, vinylcarbazole compounds, thiophene compounds or aniline compounds An oligomer or a polymer can be used.

  As more specific materials for the hole injection layer or hole transport layer, α-naphthylphenylphenylenediamine, porphyrin, metal tetraphenylporphyrin, metal naphthalocyanine, hexacyanoazatriphenylene, 7,7,8,8 -Tetracyanoquinodimethane (TCNQ), 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (F4-TCNQ), tetracyano 4,4,4-tris (3- Methylphenylphenylamino) triphenylamine, N, N, N ′, N′-tetrakis (p-tolyl) p-phenylenediamine, N, N, N ′, N′-tetraphenyl-4,4′-diaminobiphenyl N-phenylcarbazole, 4-di-p-tolylaminostilbene, poly (paraphenylene vinylene) Poly (thiophene vinylene), poly (2,2'-thienylpyrrole), and including without being limited thereto.

(Light emitting layer)
The light emitting layer is a region where emitted light is generated by recombination of holes injected from the anode side and electrons injected from the transparent electrode (cathode side). Such a light emitting layer may be an organic thin film formed of an organic material composed only of carbon and hydrogen, and is configured using a material having a tertiary amine having a hole transporting property in a molecular structure. It may be a layer. In addition, the light emitting layer may be a mixed organic thin film containing a trace amount of an organic substance such as a berylene derivative, a coumarin derivative, a pyran dye, or a triphenylamine derivative as a dopant. In this case, the light emitting layer is formed by co-evaporation of the host material (main material) constituting the light emitting layer and the material to be the dopant. In particular, a material having a tertiary amine having a hole transporting property in the molecular structure has a characteristic that the intermolecular interaction is small and the concentration quenching is difficult, so that high concentration doping is possible and optimum. Functions as one of the dopants.

  The material constituting the light emitting layer as described above can be selected according to a desired color. For example, when it is desired to obtain blue light emission, oxadiazole derivatives, cyclopentadiene derivatives, pyrazoloquinoline derivatives, distyrylarylene derivatives, oligothiophene derivatives, and the like are used. In order to obtain green light emission, a layer obtained by doping a blue light-emitting layer with a known green pigment such as a coumarin derivative such as coumarin 6 or a quinacridone derivative is used. When red light emission is desired, neil red, DCM1 {4- (dicyanomethylene) -2-methyl-6 (p-dimethylaminostyryl) -4H-pyran}, Doping with known red pigments such as DCJT {4- (dicyanomethylene) -2-t-butyl-6- (julolidylstyryl) -pyran}, pyran derivatives, squarylium derivatives, porphyrin derivatives, chlorin derivatives, eurodiline derivatives, etc. Layer is used.

  The light emitting layer may be a white light emitting layer in which a red light emitting layer, a green light emitting layer, and a blue light emitting layer are laminated, or may have a tandem structure in which a plurality of light emitting layers are laminated through a connection layer. good. Furthermore, the light emitting layer can be an electron transporting light emitting layer that also serves as an electron transporting layer, or a hole transporting light emitting layer.

(Electron transport layer)
The electron transport layer is for transporting electrons injected from the transparent electrode 104 (also referred to as a cathode) to the light emitting layer. Examples of the material for the electron transport layer include quinoline, perylene, phenanthroline, bisstyryl, pyrazine, triazole, oxazole, oxadiazole, fluorenone, and derivatives or metal complexes thereof. Specifically, tris (8-hydroxyquinoline) aluminum (abbreviated as Alq ₃ ), anthracene, naphthalene, phenanthrene, pyrene, anthracene, perylene, butadiene, coumarin, acridine, stilbene, 1,10-phenanthroline, or a derivative or metal thereof A complex.

  The light-emitting layer is not limited to such a layer structure, and it is sufficient that at least the light-emitting layer and the electron transport layer are provided in contact with the light-emitting layer. Can do.

  In addition, the light emitting layer may be provided in the organic EL element B as a hole transporting light emitting layer, an electron transporting light emitting layer, or a charge transporting light emitting layer. Furthermore, each layer constituting the organic light emitting layer 103, for example, a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer may have a laminated structure including a plurality of layers.

[Transparent electrode: cathode]
Next, a transparent electrode 104 (also referred to as a cathode) is provided on the organic light emitting layer 103 having such a configuration.

The transparent electrode 104 (also referred to as a cathode) is formed using a material having a small work function and good light transmittance. Examples of such materials include lithium oxide (Li ₂ O), which is an oxide of lithium (Li), cesium carbonate (Cs ₂ CO ₃ ), which is a composite oxide of cesium (Cs), and oxidation of these materials. Mixtures of oxides and composite oxides can be used. Further, the transparent electrode 104 (also referred to as a cathode) is not limited to such a material, and examples thereof include alkaline earth metals such as calcium (Ca) and barium (Ba), alkali metals such as lithium and cesium, Furthermore, metals having a low work function such as indium (In) and magnesium (Mg), and oxides and composite oxides, fluorides, and the like of these metals alone or these metals and oxides and composite oxides. Alternatively, it may be used as a fluoride mixture or alloy with increased stability.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<< Preparation of cellulose acylate >>
[Preparation of cellulose acylate A]
(Preparation of cellulose acylate A1)
1300 g of propionic acid was added to 300 g of cellulose (manufactured by Nippon Paper Industries Co., Ltd.) and stirred at 54 ° C. for 30 minutes. After the mixture was cooled, esterification was carried out by adding 1000 g of propionic anhydride cooled in an ice bath and 13 g of sulfuric acid. In the esterification, stirring was performed for 150 minutes while adjusting the liquid temperature so as not to exceed 40 ° C. After completion of the reaction, a mixture of 300 g of propionic acid and 100 g of water was added dropwise over 20 minutes to hydrolyze excess anhydride. While maintaining the temperature of the reaction solution at 40 ° C., 900 g of propionic acid and 300 g of water were added and stirred for 1 hour. Next, the mixture was added to an aqueous solution containing 20 g of magnesium propionate, stirred for a while and then filtered and dried to obtain cellulose acylate A1. The obtained cellulose acylate A1 is the total acyl group substitution degree _{Z 1} is 2.40, a propionyl group (3 carbon atoms) substitution degree X is 2.40, weight average molecular weight was 220,000. In addition, the measuring method of the total acyl group substitution degree and the substitution degree of a propionyl group (carbon number 3) was performed according to ASTM D-817-91.

〔セルロースアシレートＢの調製〕
（セルロースアシレートＢ１の調製）
セルロース（日本製紙（株）製溶解パルプ）３００ｇに酢酸９００ｇ、プロピオン酸２５０ｇを加え、５４℃で３０分撹拌した。混合物を冷却した後、氷浴中で冷却した無水酢酸の３２０ｇ、無水プロピオン酸５００ｇと、硫酸の１２ｇを加えてエステル化を行った。なお、エステル化においては、液温が４０℃を超えないように調節しながら、１５０分の攪拌を行った。反応終了後、酢酸３００ｇと水１００ｇの混合液を２０分かけて滴下して、過剰の無水物を加水分解した。反応液の温度を４０℃に保持しながら、酢酸９００ｇと水３００ｇを加えて１時間撹拌した。次いで、酢酸マグネシウム２０ｇを含有した水溶液中に混合物を添加し、しばらく撹拌した後にろ過、乾燥し、セルロースアシレートＢ1を得た。得られたセルロースアシレートＢ１は、総アシル基置換度Ｚ_２は２．００、プロピオニル基（炭素数３）置換度Ｙは０．５０、重量平均分子量は２２００００であった。なお、総アシル基置換度及びプロピオニル基（炭素数３）の置換度の測定方法は、ＡＳＴＭのＤ−８１７−９１に準じて行った。 [Preparation of cellulose acylates A2 to A9]
In the preparation of the cellulose acylate A1, in addition to propionic acid and propionic anhydride, acetic acid, acetic anhydride, butyric acid and butyric anhydride were used as appropriate, and the cellulose ester was similarly adjusted except that the amount of acid was adjusted. The cellulose acylates A2 to A10 having a total acyl group substitution degree Z ₁ and a propionyl group substitution degree X shown in Table 1 were prepared.

[Preparation of cellulose acylate B]
(Preparation of cellulose acylate B1)
900 g of acetic acid and 250 g of propionic acid were added to 300 g of cellulose (dissolved pulp manufactured by Nippon Paper Industries Co., Ltd.), and the mixture was stirred at 54 ° C. for 30 minutes. After the mixture was cooled, 320 g of acetic anhydride cooled in an ice bath, 500 g of propionic anhydride and 12 g of sulfuric acid were added for esterification. In the esterification, stirring was performed for 150 minutes while adjusting the liquid temperature so as not to exceed 40 ° C. After completion of the reaction, a mixed solution of 300 g of acetic acid and 100 g of water was added dropwise over 20 minutes to hydrolyze excess anhydride. While maintaining the temperature of the reaction solution at 40 ° C., 900 g of acetic acid and 300 g of water were added and stirred for 1 hour. Next, the mixture was added to an aqueous solution containing 20 g of magnesium acetate, stirred for a while and then filtered and dried to obtain cellulose acylate B1. The obtained cellulose acylate B1, the total acyl group substitution degree _{Z 2} is 2.00, a propionyl group (3 carbon atoms) substitution degree Y 0.50, weight average molecular weight was 220,000. In addition, the measuring method of the total acyl group substitution degree and the substitution degree of a propionyl group (carbon number 3) was performed according to ASTM D-817-91.

《λ/４位相差フィルムの作製》
〔λ/４位相差フィルム１の作製〕
（微粒子分散液の調製）
微粒子（アエロジル Ｒ８１２ 日本アエロジル（株）製） １１質量部
エタノール ８９質量部
以上をディゾルバーで５０分間攪拌混合した後、圧力型分散機であるマントンゴーリンを用いて分散を行った。 [Preparation of cellulose acylates B2 to B11]
In the preparation of cellulose acylate B1, in addition to acetic acid and acetic anhydride, esterification of cellulose was carried out in the same manner except that propionic acid, propionic anhydride, butyric acid and butyric anhydride were appropriately used to adjust the amount of acid. Operation was performed to prepare cellulose acylates B2 to B11 having a total acyl group substitution degree Z ₂ and a propionyl group substitution degree Y shown in Table 2.

<< Production of λ / 4 retardation film >>
[Production of λ / 4 Retardation Film 1]
(Preparation of fine particle dispersion)
Fine particles (Aerosil R812 manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed using Manton Gorin, a pressure type disperser.

(Preparation of fine particle additive solution 1)
While sufficiently stirring the inside of the dissolution tank containing 5 parts by mass of methylene chloride, 5 parts by mass of the fine particle dispersion prepared above was slowly added. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

(Preparation of main dope solution 1)
A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Entered pressure dissolution tank of organic solvents, the total acyl group substitution degree _{Z 1} is 2.40, and the cellulose acylate A1 propionyl group substitution degree X is 2.40, total acyl group substitution degree _{Z 2} is 2.00 Then, cellulose acylate B1 having a propionyl group substitution degree Y of 0.50, an ultraviolet absorber, and a fine particle additive solution 1 were added with stirring. This was completely dissolved with heating and stirring. Next, Azumi Filter Paper No. The main dope solution 1 was prepared by filtration using 244. Cellulose acylate B / cellulose acylate A (mass ratio) is 9.0.

<Composition of main dope solution 1>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acylate A1 (total acyl group substitution degree Z ₁ : 2.40, propionyl group substitution degree X is 2.40, weight average molecular weight: 220,000) 10 parts by mass Cellulose acylate B1 (Total acyl group substitution degree Z ₂ : 2.00, propionyl group substitution degree X is 0.50, weight average molecular weight: 220,000) 90 parts by mass UV absorber (Tinuvin 928, manufactured by BASF Japan Ltd.) 2.0 parts by mass 2 parts by mass of fine particle additive 1 (Formation of λ / 4 retardation film)
The prepared main dope solution 1 was uniformly cast (cast) on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm using an endless belt casting apparatus. Next, after the solvent was evaporated until the amount of residual solvent in the formed film became 75%, the film was peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

  The peeled film was stretched 1% in the width direction using a tenter while applying heat at 160 ° C. The residual solvent at the start of stretching was 15%.

  Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m.

  As described above, a roll-shaped raw film having a dry film thickness of 75 μm was obtained.

  Next, the raw film was unwound from the film unwinding step, and obliquely stretched using an oblique stretching tenter as shown in FIG. At this time, it was set as the form which unwinds from the tail in the film lamination roll wound up by the previous process.

  The roll-shaped raw film was set in a slidable feeding device of the oblique stretching apparatus shown in FIG. 2 (a) and supplied to an oblique stretching machine in which a rail pattern was set so that the angle θi = 47 °. . The zone combination at this time is a preheating zone, a transverse stretching zone, an oblique stretching zone, a holding zone, and a cooling zone. At that time, the main axis of the guide roll closest to the inlet portion of the oblique stretching tenter and the gripping tool for the oblique stretching tenter ( The distance from the clip holding part) was 80 cm. A clip having a length in the conveying direction of 5.08 cm (2 inches) and a guide roll having a diameter of 10 cm were used.

  In the oblique stretching tenter, the temperature of the preheating zone is 193 ° C., the temperature of the transverse stretching zone is 190 ° C., the temperature of the oblique stretching zone is 190 ° C., the temperature of the holding zone is 190 ° C., and the temperature of the cooling zone is 110 ° C. The take-up tension at the tenter outlet was 200 N / m.

  Drawing was performed so that the draw ratio at this time was 1.6 times. As a breakdown of the stretching ratio, the film was stretched so as to be 1.18 times in the transverse stretching zone and 1.36 times in the oblique stretching zone. At this time, the film was stretched in an oblique direction so that the orientation angle θ was 45 °. When the rail bent 45 °, it contracted 0.71 times in the direction perpendicular to the extension. The stretched film was controlled so that the fluctuation in the take-up tension was less than 3% by performing feedback control in which the change in the tension measured with the first roll on the outlet side of the obliquely stretched tenter was reflected in the take-up motor rotation speed. Thereafter, both ends of the film are trimmed, the conveyance direction is changed by a conveyance direction changing device composed of an airflow roll, the film is wound by a slidable winding device, and is formed into a roll having a thickness of 60 μm and a width of 2000 mm and having a long λ / A four retardation film 1 was obtained.

[Production of λ / 4 Retardation Films 2 to 23]
In the production of the λ / 4 retardation film 1, the types of cellulose acylate A and cellulose acylate B and the mixing ratio (cellulose acylate B / cellulose acylate A: mass ratio) of the two are listed in Table 3. Λ / 4 retardation films 2 to 23 were produced in the same manner except that each was changed.

  In the production of each λ / 4 retardation film, the stretching temperature and the stretching ratio were appropriately changed to adjust the in-plane retardation Ro to fall within the category of λ / 4 retardation.

  As a result of measuring the produced λ / 4 retardation films 1 to 23 using KOBRA-21ADH manufactured by Oji Scientific Instruments, the in-plane retardation Ro (550) measured with 550 nm light is 130 to 160 nm. The retardation Ro (650) in the in-plane direction measured with light of 650 nm was 155 to 175 nm or less, and the orientation angle θ was in the range of 45 ° ± 1 ° with respect to the film longitudinal direction.

《保護フィルム１の作製》
（エステル化合物１の調製）
１，２−プロピレングリコール２５１ｇ、無水フタル酸２７８ｇ、アジピン酸９１ｇ、安息香酸６１０ｇ、エステル化触媒としてテトライソプロピルチタネート０．１９１ｇを、温度計、撹拌器、緩急冷却管を備えた２Ｌの四つ口フラスコに仕込み、窒素気流中２３０℃になるまで、撹拌しながら徐々に昇温する。１５時間脱水縮合反応させ、反応終了後２００℃で未反応の１，２−プロピレングリコールを減圧留去することにより、エステル化合物１を得た。酸価０．１０ｍｇＫＯＨ／ｇ、数平均分子量４５０であった。 Of the above-prepared lambda / 4 phase difference film 1-2 3 cellulose acylate A, the type and mixing ratio of both the cellulose acylate B: a (cellulose acylate B / cellulose acylate A mass ratio) shown in Table 3.

<< Preparation of protective film 1 >>
(Preparation of ester compound 1)
251 g of 1,2-propylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 2 L four-neck equipped with a thermometer, stirrer, and slow cooling tube The flask is charged and gradually heated with stirring until it reaches 230 ° C. in a nitrogen stream. The ester compound 1 was obtained by making it dehydrate-condense for 15 hours, and depressurizingly distilling unreacted 1, 2- propylene glycol at 200 degreeC after completion | finish of reaction. The acid value was 0.10 mg KOH / g, and the number average molecular weight was 450.

(Preparation of main dope solution 2)
Cellulose acetate (acetyl group substitution degree: 2.88, weight average molecular weight: about 190,000)
90 parts by mass Ester compound 1 10 parts by mass UV absorber (Tinubin 928, manufactured by BASF Japan) 2.5 parts by mass Fine particle additive 1 (supra) 4 parts by mass Methylene chloride 432 parts by mass Ethanol 38 parts by mass The solution was completely dissolved while being stirred and heated, and Azumi filter paper No. manufactured by Azumi Filter Paper Co., Ltd. was used. 24 was used to prepare the main dope solution 2.

(Protective film formation)
Next, the main dope liquid 2 was uniformly cast on the stainless steel band support using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100%, and the stainless steel band support was peeled off. Cellulose ester film web was evaporated at 35 ° C, slitted to 1.65m width, 30% in TD direction (film width direction) with a tenter while applying heat at 160 ° C, MD draw ratio was Stretched 1%. The residual solvent amount when starting stretching was 20%. Then, after drying for 15 minutes while transporting the inside of a drying device at 120 ° C. with a number of rolls, slitting to a width of 1.49 m, applying a knurling process with a width of 15 mm and a height of 10 μm at both ends of the film, and winding it around a winding core The protective film 1 was obtained. The residual solvent amount of the protective film 1 was 0.2%, the film thickness was 40 μm, and the number of turns was 3900 m.

  As a result of measuring the orientation angle θ of the protective film 1 using KOBRA-21ADH manufactured by Oji Scientific Instruments, it was in the range of 90 ° ± 1 ° with respect to the longitudinal direction of the film.

<Production of circularly polarizing plate>
(Production of polarizer)
A polyvinyl alcohol film having a thickness of 120 μm was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer.

[Production of Circular Polarizing Plate 1]
Next, the polarizer, the λ / 4 phase difference film 1 and the protective film 1 are bonded to the back side (viewing side) by roll-to-roll so as to match in the longitudinal direction in accordance with the following steps 1 to 5 and circularly polarizing plates. 1 was produced.

  Step 1: The λ / 4 retardation film 1 and the stretched protective film 1 are immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried, and the side to be bonded to the polarizer is attached. Saponified.

  Process 2: The said polarizer was immersed in the polyvinyl alcohol adhesive tank of 2 mass% of solid content for 1-2 seconds.

  Step 3: Excess adhesive adhered to the polarizer in Step 2 was gently wiped, and this was placed on the λ / 4 retardation film 1 processed in Step 1.

Step 4: The λ / 4 retardation film 1, the polarizer, and the protective film 1 laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min.

  Step 5: A sample obtained by bonding the polarizer prepared in Step 4 to the λ / 4 retardation film 1 and the protective film 1 in a dryer at 80 ° C. was dried for 2 minutes to prepare a circularly polarizing plate 1.

[Production of Circular Polarizing Plates 2 to 23]
In the production of the circularly polarizing plate 1, circularly polarizing plates 2 to 23 were produced in the same manner except that the λ / 4 retardation films 2 to 23 were used in place of the λ / 4 retardation film 1, respectively.

<< Preparation of organic electroluminescence display device >>
Organic electroluminescence display devices 1 to 23 having the configuration shown in FIG. 6 were produced.

さらに、発光層上に電子が効率的に注入できるような仕事関数の低い第１の陰極としてカルシウムを真空蒸着法により４ｎｍの厚さで成膜し、第１の陰極上に第２の陰極としてアルミニウムを２ｎｍの厚さで形成した。ここで、第２の陰極として用いたアルミニウムはその上に形成される透明電極４ａをスパッタリング法により成膜する際に、第１の陰極であるカルシウムが化学的変質をすることを防ぐ役割がある。以上のようにして、有機発光層を得た。次に、陰極上にスパッタリング法によって透明導電膜を８０ｎｍの厚さで成膜した。ここで透明導電膜としてはＩＴＯを用いた。さらに、透明導電膜上にＣＶＤ法によって窒化珪素を２００ｎｍ成膜することで、絶縁膜５ａとした。 [Production of organic EL display element]
As shown in FIG. 6, a reflective electrode made of chromium is formed on a transparent glass substrate 1a, ITO is formed on the reflective electrode as a metal electrode 2a (anode), and poly (3,4) is formed on the anode as a hole transport layer. -Ethylenedioxythiophene) -polystyrene sulfonate (PEDOT: PSS) is formed by sputtering at a thickness of 80 nm, and then a shadow mask is used on the hole transport layer, and as shown in FIG. 3aG and 3aB were formed with a film thickness of 100 nm. As the red light emitting layer 3aR, tris (8-hydroxyquinolinate) aluminum (Alq ₃ ) and a light emitting compound [4- (dicyanomethylene) -2-methyl-6 (p-dimethylaminostyryl) -4H-pyran] ( DCM) were co-evaporated (mass ratio 99: 1) to form a thickness of 100 nm. The green light emitting layer 3aG was formed to a thickness of 100 nm by co-evaporating Alq ₃ as a host and the light emitting compound coumarin 6 (mass ratio 99: 1). The blue light emitting layer 3aB was formed with a thickness of 100 nm by co-evaporating BAlq and a light emitting compound Perylene as a host (mass ratio 90:10).

Further, calcium is deposited to a thickness of 4 nm by vacuum deposition as a first cathode having a low work function so that electrons can be efficiently injected onto the light emitting layer, and a second cathode is formed on the first cathode. Aluminum was formed with a thickness of 2 nm. Here, the aluminum used as the second cathode has a role to prevent calcium as the first cathode from being chemically altered when the transparent electrode 4a formed thereon is formed by sputtering. . As described above, an organic light emitting layer was obtained. Next, a transparent conductive film was formed to a thickness of 80 nm on the cathode by sputtering. Here, ITO was used as the transparent conductive film. Furthermore, a silicon nitride film having a thickness of 200 nm was formed on the transparent conductive film by a CVD method to form the insulating film 5a.

The light emitting area of the produced organic EL element was 1296 mm × 784 mm. Further, the front luminance when a DC voltage of 6 V was applied to the organic EL element was 1200 cd / m ² . The front luminance is measured using a spectral radiance meter CS-1000 manufactured by Konica Minolta Sensing Co., Ltd. with the front luminance at 2 ° C. and the optical axis of the spectral radiance meter aligned with the normal from the light emitting surface. The range of visible light wavelength of 430 to 480 nm was measured, and the integrated intensity was taken.

[Production of organic EL display devices 1 to 23]
Each of the circularly polarizing plates 1 to 23 on which the prepared polarizer and the λ / 4 retardation film are mounted are opposed to the prepared organic EL display element so as to have the configuration shown in FIG. 6. The organic EL display devices 1 to 23 were produced by fixing the film via the substrate.

<< Evaluation of organic EL display >>
[Evaluation of visibility]
(Evaluation of visibility 1: visibility under normal temperature and humidity environment)
Each of the produced organic EL display devices is stored for 48 hours in an environment of 23 ° C. and a relative humidity of 55%, and at a position 5 cm higher than the outermost surface of the organic EL display device with no voltage applied and no light emission. Each of the visibility from an angle of 40 ° with respect to the normal line of the screen of the organic EL display device is visually confirmed under two conditions of condition A where the illuminance of the light becomes 500 Lx and condition B where the illuminance is 1000 Lx. The visibility in a normal temperature and humidity environment was evaluated.

  The visibility evaluation is performed by 10 people, and the visibility at 500 Lx which is condition A is compared with the visibility at 1000 Lx which is condition B. The visibility at condition B (1000 Lx) is the visibility at condition A (500 Lx). If it is judged that the visibility is slightly lowered, it is “2 points”. If it is judged that the visibility is slightly lowered, it is “1 point”. When it was determined that the visibility was low, “0 point” was assigned. The total score of 10 evaluation scores was obtained, and the visibility in a normal temperature and humidity environment was determined according to the following evaluation rank.

◎: Total score is 27 or more ○: Total score is 24 or more and 26 or less △: Total score is 18 or more and 23 or less ×: Total score is 17 or less (viewing Evaluation of property 2: Visibility under high temperature and high humidity environment)
Each of the produced organic EL display devices is stored for 48 hours in an environment of 40 ° C. and a relative humidity of 80%, and no voltage is applied and no light is emitted at a position 5 cm higher than the outermost surface of the organic EL display device. The visibility is visually confirmed from an angle of 40 ° with respect to the normal line of the screen of the organic EL display device under the condition C where the illuminance is 1000 Lx, and the visibility in a high temperature and high humidity environment is evaluated according to the following criteria. did.

  The visibility evaluation was performed by 10 persons, and the visibility in Condition B (1000 Lx) performed in the above-described evaluation of visibility 1 was compared with the visibility in Condition C after storage at high temperature and high humidity. (3 points) if the visibility in the treatment (after treatment) is equivalent to the visibility in Condition B (stored at room temperature and normal humidity), "2 points" if it is judged that the visibility is slightly lowered, When it was judged that the visibility was slightly lowered, it was set to “1 point”, and when it was judged that the visibility was clearly lowered, it was set to “0 point”. The total score of 10 evaluation scores was obtained, and the visibility in a high temperature and high humidity environment was determined according to the following evaluation rank.

◎: Total score is 27 or more ○: Total score is 24 or more and 26 or less △: Total score is 18 or more and 23 or less ×: Total score is 17 or less [Durability (Evaluation of properties: resistance to unevenness in image display against environmental temperature changes)
Each of the produced organic EL display devices is stored in a dry environment (relative humidity of 20% or less) for 10 minutes at 20 ° C. in a dry environment (relative humidity of 20% or less), and then forcibly deteriorated by storing at 50 ° C. for 10 minutes (this) 1 cycle) is taken out from the thermal shock tester, and the image display unevenness when the white display is performed is compared with the white display image before the forced deterioration process, and the following is observed. Durability was evaluated according to standards.

◎: There is no difference in image quality during white display before and after forced deterioration processing. ○: Slight image display unevenness is observed after forced deterioration processing. △: Some image display unevenness after forced deterioration processing. X: After the forced deterioration treatment, clear image display unevenness is observed, and the generation of pixels that do not emit light is observed [Evaluation of saponification suitability (adhesion)]
A polarizer and a polarizing plate were prepared according to the following steps 1 to 6, and adhesion (saponification suitability) was evaluated.

<Process 1>
A polyvinyl alcohol film having a thickness of 50 μm was uniaxially stretched in the film forming direction (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 6 g of potassium iodide, and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of a ratio of 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. . This was washed with water and dried to obtain a polarizer. This polarizer had an absorption axis in the film forming direction.

<Process 2>
As a protective film for a polarizing plate, each λ / 4 retardation film produced was immersed in a 4 mol / L potassium hydroxide aqueous solution at 50 ° C. for 60 seconds, then washed with water, dried and bonded to a polarizer. Saponified.

  Similarly, saponification of commercially available cellulose ester film 4UY (manufactured by Konica Minolta Opto Co., Ltd.) was also performed as a protective film for the polarizing plate on the opposite side.

<Process 3>
The polarizer was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.

<Step 4>
The excess adhesive adhered to the polarizer in the above step 3 is gently wiped off, and this is placed on the surface of each λ / 4 retardation film saponified in the step 2, and further as a protective film for polarizing plate on the opposite side, Lamination was performed so that the saponified surface of the commercially available cellulose ester film 4UY treated in Step 2 was in contact with the polarizer, and a polarizing plate was produced.

<Step 5>
The polarizing plate obtained by laminating the film and the polarizer in the above step 4 was bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min.

<Step 6>
Each polarizing plate bonded in the above step 5 is cut to a size of 5 cm × 7 cm, and both ends on the long side of the obtained polarizing plate piece are firmly sandwiched between clips, and each clip is polarized in an oven at 60 ° C. The plate pieces were hung vertically and dried.

  After 5 minutes, after taking out from the oven and adjusting the humidity sufficiently in an environment of 23 ° C. and 55% RH, a test for peeling the evaluation film from the polarizer by hand from the end of the polarizing plate is performed. The adhesion to the polarizer was evaluated, and this was used as a measure of saponification suitability.

◎: Even if you try to peel off with force, it will not peel off at all ○: When force is applied, it will peel from the edge to less than 1 mm around △: When force is applied, it will peel from the edge to around 1 mm or more but less than 3 mm ×: Edge Peeling occurs in a range wider than 3 mm from the part [Evaluation of film thickness]
About the produced (lambda) / 4 phase difference film, the film thickness in case of Ro (550) = 138 was measured, and it evaluated in accordance with the following reference | standard. For the measurement of the film thickness, a Nikon optical microscope, MS-5C, was used.

表４に記載の結果より明らかなように、本発明で規定する構成からなるλ/４位相差フィルムを備えた有機ＥＬ表示装置は、比較例に対し、薄膜で、常温常湿あるいは高温高湿環境下で保存した後の視認性、耐久性に優れ、鹸化適性（密着性）が向上していることが分かる。 ○: The film thickness of the λ / 4 retardation film is 50 μm or more and less than 70 μm. Δ: The film thickness of the λ / 4 retardation film is 70 μm or more and less than 90 μm. The film thickness of the λ / 4 retardation film is 90 μm or more. Table 4 shows the results obtained.

As is clear from the results shown in Table 4, the organic EL display device provided with the λ / 4 retardation film having the configuration defined in the present invention is a thin film, at room temperature and normal humidity or at high temperature and high humidity, as compared with the comparative example. It can be seen that it has excellent visibility and durability after storage in an environment, and has improved saponification suitability (adhesion).

4 Long Film Original 5 Long Stretched Film 6 Diagonally Stretched Tenter 7-1 Trajectory of Outer Film Gripping Unit 7-2 Trajectory of Inner Film Gripping Unit 8-1 Outer Film Gripping Start Point 8-1 Inner Film Gripping start point 9-1 Outer film gripping end point 9-2 Inner film gripping end point 10-1 Outer oblique stretching start point 10-2 Inner oblique stretching start point 11-1 Outer oblique stretching end point 11-2 Inward oblique Stretching end point 12-1 Guide roll on the tenter inlet side 12-2 Guide roll on the tenter outlet side 13 Film stretching direction 14-1 Film transport direction before oblique stretching 14-2 Film transport direction after oblique stretching Wo Diagonal Film width before stretching W Film width after oblique stretching 101, 1a substrate, transparent substrate 102, 2a metal electrode 103 Layer 3aR Red coloring layer 3aG Green coloring layer 3aB Blue coloring layer 104, 4a Transparent electrode 105, 5a Insulating layer 106 Sealing layer 6a Adhesive layer 107 Film 108, 7a λ / 4 retardation film 109, 8a Polarizer 110, 9a Protection Film 111 Surface antireflection layer 10a, C Circularly polarizing plate 11a, B Organic EL display element 16 Film feeding device 17 Conveyance direction changing device 18 Winding device 19 Film forming device

Claims (4)

From the viewing side, in the organic electroluminescence display device having a protective film, a polarizer, a λ / 4 retardation film and an organic electroluminescence element in this order,
The λ / 4 retardation film is
The in-plane retardation Ro (550) measured with 550 nm light is 130 nm or more and 160 nm or less,
In-plane retardation Ro (650) measured with 650 nm light is 155 nm or more and 175 nm or less,
The ratio of the Ro (550) to the Ro (650) (Ro (550) / Ro (650)) is 0.80 or more and 0.90 or less,
At least as cellulose acylate, cellulose acylate A that simultaneously satisfies the conditions specified by the following formulas (1) and (2), and cellulose acylate B that simultaneously satisfies the conditions specified by the following formulas (3) and (4) And containing
An organic electroluminescence display device, wherein the mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) is 1.0 or more and 19.0 or less.
Equation _{(1) 2.5 ≦ Z 1 <} 3.0
Formula (2) 2.5 <= X <= 3.0
Formula (3) 2.0 ≦ Z ₂ <2.5
Formula (4) 0.5 <= Y <= 1.5
(In the formula, Z ₁ and Z ₂ each represent the total acyl group substitution degree of cellulose acylate, and X and Y each represent the substitution degree of an acyl group having 3 or more carbon atoms in cellulose acylate.)   2. The mass ratio of cellulose acylate B to cellulose acylate A (cellulose acylate B / cellulose acylate A) is 2.0 or more and 9.0 or less, according to claim 1. Organic electroluminescence display device. 3. The organic electro of claim 1, wherein Z ₁ in the cellulose acylate A satisfies a condition defined by the following formula (5), and X satisfies a condition defined by the following formula (6). Luminescence display device.
Formula (5) 2.7 ≦ Z ₁ ≦ 2.9
Formula (6) 2.7 ≦ X ≦ 2.9 4. The cellulose acylate B according to claim 1, wherein Z ₂ in the cellulose acylate B satisfies a condition defined by the following formula (7), and Y satisfies a condition defined by the following formula (8). The organic electroluminescence display device described in 1.
Formula (7) 2.3 ≦ Z ₂ <2.5
Formula (8) 0.8 <= Y <= 1.2

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