WO2002041072A1 - Semitransparent liquid crystal display device - Google Patents

Abstract

A semitransparent liquid crystal display device comprising a liquid crystal cell in which a liquid crystal material layer is interposed between a pair of transparent substrates having electrodes, a linear polarization plate, an optical compensation device having a twist structure, a semitransparent reflecting plate, and a circular polarization plate, wherein a drive voltage the value of which is selected from two or more values is applied to the liquid crystal material layer, whereby the display can perform display even in a reflection or transmission mode, characterized in that the linear polarization plate is disposed on one side of the liquid crystal material layer, the circular polarization plate is disposed on the other side of the liquid crystal material layer, the semitransparent reflecting plate is disposed between the liquid crystal material layer and the circular polarization plate, the optical compensation device is disposed between the linear polarization plate and the semitransparent reflecting plate, the birefringent chromatic dispersion α1 of the liquid crystal material layer is α1=1.01 to 1.35 and the birefringent chromatic dispersion α2 of the optical compensation device is α2=1.11 to 1.40 where the birefringent chromatic dispersion a is the ratio between the birefringent Δn at the wavelength μ=450 nm and the birefringent Δn at the wavelength μ=590 nm.

Description

 Description Transflective LCD device

[Technical field]

 The present invention relates to a transflective liquid crystal display device capable of displaying in either a reflection mode or a transmission mode.

[Background technology]

 In recent years, there has been increasing expectations for the market expansion of liquid crystal display devices as displays for portable information terminal devices, which can make full use of their thin and lightweight features. Since portable electronic devices are usually battery-powered, reducing power consumption is an important issue. Therefore, as a liquid crystal display element for portable use, a reflective liquid crystal display element that does not use a backlight that consumes a large amount of power or does not need to use it all the time can be used, and it is possible to reduce power consumption, make it thinner and lighter. Has received particular attention.

 2. Description of the Related Art Conventionally, as a liquid crystal display element, a TN (twisted nematic) mode and an STN (super twisted nematic) mode are mainly used. The above STN-type liquid crystal display element generally has a structure in which a liquid crystal cell is sandwiched between a pair of polarizing plates. In the case of a reflective liquid crystal display element, a structure in which a reflective plate is further disposed outside the liquid crystal cell is usually provided. Have. In the STN mode liquid crystal display device, the twist angle of the liquid crystal molecules in the liquid crystal cell is set to 90 ° or more, and the setting angle of the transmission axis of the polarizing plate with respect to the elliptically polarized light generated by the birefringence effect of the liquid crystal cell is optimized. Therefore, abrupt molecular orientation deformation due to voltage application can be reflected in the birefringence change of the liquid crystal, and electro-optical characteristics exhibiting a sudden optical change above a threshold can be realized.

In the STN mode liquid crystal display device, yellow green or dark blue may be generated as a display background color due to birefringence of the liquid crystal. In order to improve this coloring phenomenon, an optical compensation liquid crystal cell or a retardation plate formed of a polymer such as polycarbonate or a twisted retardation film is superimposed on the STN liquid crystal cell for display. As a result, there is no liquid crystal display element configured to perform color compensation and display almost black and white. It is used as a so-called paper white liquid crystal display device.

 However, in the STN mode liquid crystal display device, the transmittance of the polarizing plate is about 90% even when linearly polarized light is incident parallel to the polarization axis, and the conventional configuration using two polarizing plates is used. However, there is a problem that sufficient brightness cannot be obtained. In particular, in the case of a reflective liquid crystal display element, the backlight is not used, and the incident light passes through the polarizing plate a total of four times before being emitted.

 As a conventional technique for solving this problem, there is a technique described in Japanese Patent Publication No. 2-1899519 or Japanese Patent Publication No. 6-11171. These have a configuration in which a polarizing plate, a retardation plate, a liquid crystal cell and a reflecting plate are laminated in this order, that is, a polarizing plate on the reflecting plate side from a reflection type liquid crystal display device using a commonly used STN type liquid crystal cell. A liquid crystal display device having a configuration excluding a plate is disclosed. By adopting such a configuration, the number of times that the incident light passes through the polarizing plate before the light is emitted becomes twice, so that a high luminance is inevitably obtained and a white display with high reflectivity is achieved. Be expected. However, when a reflective liquid crystal display device having such a configuration is formed, the degree of freedom in terms of structure, in which polarized light before and after reflection is shared by a single polarizing plate, is low. It is difficult to configure each layer to give a good high contrast display.

Furthermore, since these reflective liquid crystal display elements usually perform display using external light, they have a drawback that display becomes invisible or invisible when used in a dark environment. As a technique for solving this problem, as described in Japanese Patent Application Laid-Open No. H10-206864, in a reflection type liquid crystal display device having a single polarizing plate, a part of incident light is used instead of the reflection plate. A transflective liquid crystal display device using a transflective reflector having a transmissive property and having an auxiliary light source such as a backlight has been proposed. In this case, the backlight can be used as a reflection type (reflection mode) using external light when the backlight is not lit, and as a transmission type (transmission mode) with the backlight lit in a dark environment. However, in this transflective liquid crystal display device, it is necessary to drive the reflective mode and the transmissive mode in conjunction with each other. In the transmissive mode, a polarizing plate and a retardation plate are provided between the transflective plate and the backlight. The optical design for good display had the problem that it became more complicated, such as the necessity of more. SUMMARY OF THE INVENTION An object of the present invention is to provide a transflective liquid crystal display element which has bright display, high contrast, good color, and easy optical design for both reflective display and transmissive display.

[Disclosure of the Invention]

 That is, a first aspect of the present invention is a liquid crystal cell in which a layer of a liquid crystal substance is inserted into a pair of transparent substrates having electrodes, a linear polarizing plate, an optical compensation element having a twisted structure, a semi-transmissive reflecting plate, A transflective liquid crystal display element, wherein a voltage value of two or more values is selected and a driving voltage is applied to the liquid crystal material layer,

 The linear polarizing plate is disposed on one surface side of the liquid crystal material layer,

 The circularly polarizing plate is disposed on the other surface side of the liquid crystal material layer,

 The transflective plate is disposed between the liquid crystal material layer and the circularly polarizing plate,

 The optical compensating element is disposed between the linear polarizer and the transflector, and determines the ratio of birefringence △ n at wavelength input = 450 nm and f = 590 nm to the birefringence wavelength dispersion.

 α = Δn (4500) / Δn (590)

If you define

Birefringence wavelength dispersion alpha ₂ of the birefringence wavelength dispersion ai and optical compensation elements of the liquid crystal material layer, ai = 1. 0 1~ 1 . 3 5

 2 = 1. 1 1— 1. 4 0

And a transflective liquid crystal display device.

A second aspect of the present invention is that the birefringence wavelength dispersion of the liquid crystal material layer and the birefringence wavelength dispersion α _{2 of the} optical compensation element are:

 α! <2.

And the transflective liquid crystal display element described above. A third aspect of the present invention is that the twist angle 液晶 of the liquid crystal substance molecules from the side of the linear polarizing plate to the side of the semi-transmissive reflection plate in the liquid crystal substance layer is in a range of not less than +200 degrees and not more than +270 degrees. The twist angle 6> ₂ of the slow axis of the optical compensator from the side of the linear polarizer to the side of the semi-transmissive reflector is in the range of −220 degrees or more and 150 degrees or less; Layer wavelength; 1 = 550! ! ! ! ! Birefringence! The product of ^ and the thickness d (Arii-di) is in the range of 700 nm or more and 1000 nm or less, and the wavelength of the optical compensator is birefringence An ₂ and the thickness of the optical compensator at 550 nm. about transflective type liquid crystal display device of the, wherein the product of _{d 2 (Δη 2 · d 2} ) is in the range below 5 5 0 nm or more 850 nm.

 A fourth aspect of the present invention is that the circularly polarizing plate is at least constituted by a linear polarizing plate and an optically anisotropic element, and the optically anisotropic element has a twisted structure. Liquid crystal display device.

In the fifth aspect of the present invention, the wavelength of the optically anisotropic element constituting the circularly polarizing plate; the product (Δη ₃ · d ₃ ) of birefringence △ n ₃ and thickness d ₃ (nm) at I = 550 nm is And the twist angle θ ₆ from the linear polarizing plate side to the circular polarizing plate side of the slow axis of the optically anisotropic element is 30 ° or more and 85 ° or less in absolute value. The present invention relates to the above-mentioned transflective liquid crystal display element.

A sixth aspect of the present invention provides a product (Δη ₃ · d ₃ ) of the birefringence △ η ₃ and the thickness d ₃ (nm) at a wavelength of 550 nm of the optically anisotropic element constituting the circularly polarizing plate, and twist angle 0 ₆ from linear polarizing plate side of the slow axis of the optically anisotropic element into circularly polarizing plate side,

 (1) 1 55 nm or more and 1 75 nm or less and 40 to 50 degrees in absolute value,

(2) One of 176 nm or more and 216 nm or less and 58 to 70 degrees in absolute value, (3) One of 230 nm to 270 nm or less and 70 to 80 degrees in absolute value The transflective liquid crystal display element described above, wherein the following condition is satisfied.

 Further, the seventh aspect of the present invention relates to the above-mentioned transflective liquid crystal display element, further comprising at least one light diffusion layer between the linear polarizing plate and the transflective plate. Hereinafter, the present invention will be described in detail. .

 The transflective liquid crystal display device of the present invention comprises at least a liquid crystal cell, a linear polarizer, an optical compensator, a transflector, and a circular polarizer.

The liquid crystal cell of the present invention has a pair of transparent substrates provided with electrodes and a layer of a liquid crystal substance inserted between the substrates. As the transparent substrate, the liquid crystal material is A material that is oriented in the opposite direction can be used. Specifically, either a transparent substrate having the property of aligning the liquid crystal substance itself or a transparent substrate provided with an alignment film or the like having the property of aligning the liquid crystal substance can be used. By holding two transparent substrates having such a specific alignment direction so that the alignment directions are twisted, and forming a layer of a liquid crystal material between the transparent substrates, the liquid crystal material is formed. Can be given a specific twist angle. In addition, the electrode of the liquid crystal cell can be usually provided on the surface of the transparent substrate where the layer of the liquid crystal substance is in contact. When a transparent substrate having an alignment film is used, it is provided between the transparent substrate and the alignment film. be able to. As the liquid crystal substance, various substances usually used for STN type liquid crystal display devices can be used.

 In the transflective liquid crystal display element of the present invention, two or more voltage values are selected, and a driving voltage is applied to the liquid crystal material layer. The voltage value of the two or more values is not particularly limited as long as it is an effective voltage value for performing liquid crystal display, and may be a voltage value before and after a sharp change in reflectance or transmittance occurs. it can. Thus, the layer of the liquid crystal material can function as an active optical layer that provides a bright achromatic color and a dark achromatic color.

In the present invention, the birefringence wavelength dispersion of a liquid crystal material used in a liquid crystal cell described later! By setting the birefringence wavelength dispersion ₂ of the optical compensator described later in a specific numerical range, the effect of the present invention can be obtained. The birefringence (= refractive index anisotropy) Δη of the liquid crystal material used in the liquid crystal cell generally depends on the wavelength (nm), and the characteristics generally tend to be negative with respect to the wavelength. Having. That is, the ratio of the birefringence of the liquid crystal material at the wavelength λ = 450 nm and the input wavelength of 590 nm (hereinafter, referred to as “△ ri! (450)” and rA ri i (590)), respectively. Is referred to as birefringence wavelength dispersion.

 Birefringence wavelength dispersion of the liquid crystal material in the liquid crystal cell constituting the present invention! To

a, = A, (4 5 0) / Δ η _χ (5 9 0)

Then, usually i> l. They are identical if the liquid crystal materials are exactly the same, but may be the same for different liquid crystal materials. In the present invention, the relationship between the birefringence wavelength dispersion alpha ₂ of the optical compensation element to be described later, shed _{1 =} 1.0 1 to 1.3 5 to express the effects of the more prominent the present invention in the case der Ru Can be. The twist angle θ 1 of the liquid crystal substance molecules from the side of the linear polarizer to the side of the semi-transmissive reflector (circular polarizer) in the layer of the liquid crystal substance in the liquid crystal cell is usually + 200 ° to 270 °. It is desirable to be within the range. When the torsion angle is less than + 200 °, there is little change in the liquid crystal state when time-division driving is performed at a high duty ratio that requires a sharp change in reflectance and transmittance. If it exceeds + 270 °, hysteresis tends to occur. In the present specification, the positive direction of the angle and the one direction mean the rotational direction of the relative angle, and the clockwise direction when the counterclockwise direction from the linear polarizing plate toward the circular polarizing plate is +. The direction becomes one, and conversely, if the clockwise direction is +, the counterclockwise direction becomes one. However, either case is included in the scope of the present invention, and the same effect can be obtained.

 Further, the product (Δη! · D) of the refractive index anisotropy Δηe and the thickness di of the liquid crystal material layer in the liquid crystal cell is desirably in the range of 700 nm to 100 nm. If it is less than 700 nm, the change in the state of the liquid crystal when a voltage is applied is small, and if it exceeds 100 nm, the viewing angle characteristics and responsiveness may deteriorate.

 The linear polarizing plate constituting the present invention is disposed on one side of the liquid crystal material layer. In general, it is usually arranged on one of the front surface and the back surface of the liquid crystal cell, in other words, on the transparent substrate surface which is not the liquid crystal material layer interface side of one transparent substrate. A linear polarizing plate can be arranged between the liquid crystal material layer, that is, in the liquid crystal cell. When a linear polarizing plate is provided on the front surface or the back surface of the liquid crystal cell, the linear polarizing plate may be provided via an optical compensator or the like.

 The linear polarizing plate used in the present invention is not particularly limited, and a polarizing plate usually used for a liquid crystal display device can be appropriately used. To be more specific, PVA-based polarizing films such as polyvinyl alcohol (PVA) and partially acetalized PVA, hydrophilic polymer films made of partially saponified ethylene monoacetate vinyl copolymer, etc. A polarizing film formed by adsorbing and / or stretching a dichroic dye, or a polarizing film made of a polyene oriented film such as a dehydrated PVA product or a dehydrochlorinated polyvinyl chloride product can be used.

The linear polarizing plate may be used as a polarizing film alone, or may have a transparent protective layer or the like on one or both surfaces of the polarizing film for the purpose of improving strength, improving moisture resistance, improving heat resistance, and the like. It may be provided. Examples of the transparent protective layer include a transparent plastic film such as polyester / triacetyl cellulose laminated directly or via an adhesive layer, a resin coating layer, and a photo-curable resin layer such as an acrylic or epoxy resin. Can be When these transparent protective layers are coated on both sides of the polarizing film, the same protective layer may be provided on both sides, or different protective layers may be provided.

 The optical compensating element constituting the present invention means an element having an optical anisotropic axis and having a structure in which the optical anisotropic axis is twisted from one surface to the other surface. Therefore, the optical compensating element referred to here has the same characteristics as those obtained by superposing a plurality of optically anisotropic layers so that the optically anisotropic axes of the layers are continuously twisted. It has a twist angle like a normal TN liquid crystal cell.

 The optical compensation element of the present invention is disposed between the linear polarizing plate and a semi-transmissive reflecting plate described later. Usually, it is arranged between the linear polarizing plate and the liquid crystal cell or between the liquid crystal cell and the transflective plate, but it is particularly preferable to provide between the linear polarizing plate and the liquid crystal cell.

 As the optical compensation element, a twisted liquid crystal cell itself ', a liquid crystal film, a laminate of a retardation film, or the like can be used.

 The twist-aligned liquid crystal cell includes a liquid crystal in which a layer of a liquid crystal substance inserted between two transparent substrates is oriented in a specific direction to give a twist angle, similarly to the driving liquid crystal cell described above. A cell can be mentioned as an example.

 In addition, the liquid crystal film means a film having a structure in which a layer having an optically anisotropic axis is continuously twisted in one film. This liquid crystal film can be generally obtained by forming a liquid crystal material having a twist characteristic into a film. In such a liquid crystal film, a liquid crystal material exhibiting nematic liquid crystal properties is twisted and nematically aligned, and then the alignment structure is fixed by, for example, photo-crosslinking or thermal cross-linking, or is fixed in a glass state by cooling. It can be obtained by such a method.

The liquid crystal material is not particularly limited as long as it has a nematic liquid crystal property, and various low-molecular liquid crystal materials, high-molecular liquid crystal materials, or a mixture thereof can be used as the material. Whether the molecular shape of the liquid crystal substance is rod-shaped or disc-shaped Regardless, for example, a discotic liquid crystal having a discotic nematic liquid crystal property can also be used. Further, when these mixtures are used as a liquid crystal material, if the material can finally form a desired twisted structure and the orientation structure can be fixed, the composition of the material or the There are no restrictions on the composition ratio or the like. For example, a mixture of a single or multiple types of low-molecular and / or high-molecular liquid crystal materials, a single or multiple types of low-molecular and / or high-molecular non-liquid crystalline materials, and various additives is used as the liquid crystal material. Can also.

 Examples of the low-molecular liquid crystal material include dip base, biphenyl, terphenyl, ester, thioester, stilbene, tolan, azoxy, azo, phenylcyclohexane, pyrimidine, and cycloalkyl. Hexylcyclohexane-based, trimesic-acid-based, triphenylene-based, tolcene-based, phthalocyanine-based, and porphyrin-based low-molecular liquid crystal compounds having a molecular skeleton, and mixtures of these compounds.

 As the polymer liquid crystal substance, various kinds of main chain polymer liquid crystal substances, side chain polymer liquid crystal substances, or mixtures thereof can be used. The main-chain polymer liquid crystal materials include polyester, polyamide, polycarbonate, polyimide, polyurethane, polybenzimidazole, polybenzoxazole, polybenzothiazole, polyazomethine, Examples thereof include polyester amide-based, polyester-based carbonate-based, polyester imid-based polymer liquid crystals, and mixtures thereof. Among these, semi-aromatic polyester polymer liquid crystals in which mesogenic groups providing liquid crystallinity and bent chains of polymethylene, polyethylene oxide, polysiloxane, etc. are alternately bonded, and wholly aromatic polyesters without bent chains Polymer liquid crystals are preferred in the present invention.

The side-chain type polymer liquid crystal material includes a linear or cyclic structure such as a polyacrylate, a polymethacrylate, a polyvinyl, a polysiloxane, a polyether, a polymer and a polyester. Examples include a polymer liquid crystal in which a mesogen group is bonded as a side chain to a substance having a skeletal chain, or a mixture thereof. Among these, a side-chain type polymer liquid crystal in which a mesogen group that provides liquid crystallinity via a spacer composed of a bent chain is bonded to a backbone chain, and a molecule having a mesogen in both the main chain and the side chain. Such a polymer liquid crystal having a structure is desirable in the present invention.

 It is particularly desirable that the liquid crystal material contains a chiral agent or various liquid crystal materials or at least one non-liquid crystal material having at least one chiral structural unit in order to induce twisted nematic alignment.

 Chiral structural units include, for example, optically active 2-methyl-1,4-butanediol, 2,4-pentynediol, 1,2-propanediol, 2-chloro-1,4-butanediol, 2 —Fluoro 1,4-butanediol, 2-butane 1,4-butanediol, 2-ethyl-1,4-butanediol, 2-pulp-1,4-butanediol, 3-methyl Uses units derived from xandiol, 3-methyladipic acid, naproxen derivatives, camphoric acid, binaphthol, menthol, or a cholesteryl group-containing structural unit or a derivative thereof (for example, a derivative such as a diacetoxy compound). can do. The above chiral structural unit may be any of the R-form and the S-form, or may be a mixture of the R-form and the S-form. These structural units are merely examples, and the present invention is not limited thereto.

 When fixing the alignment structure formed in the liquid crystal state by thermal crosslinking or photocrosslinking when preparing a liquid crystal film, the liquid crystal material has a functional group or site that can react by heat or photocrosslinking reaction. It is desirable to mix various liquid crystal substances, and examples of the functional group capable of performing a cross-linking reaction include an acryl group, a methyl group, a vinyl group, a vinyl ether group, an aryl group, an aryloxy group and a glycidyl group. Examples of the group include an epoxy group, a dissocyanate group, an isothiocyanate group, an azo group, a diazo group, an azide group, a hydroxyl group, a carboxyl group, and a lower ester group. Acryl group and methacryl group are particularly preferable. The sites capable of undergoing a cross-linking reaction include maleimide, maleic anhydride, cinnamic acid and cinnamic acid ester, alkene, gen, allene, alkyne, .azo, azoxy, disulfide, and polysulfide. And other sites containing a molecular structure. These cross-linking groups and cross-linking reaction sites may be included in the various liquid crystal materials constituting the liquid crystal material itself, but a non-liquid crystal material having a cross-linking group or site may be separately added to the liquid crystal material.

As another example that can be used as an optical compensating element constituting the present invention, the liquid crystal film As in the case of the film, a laminate of a retardation film having a pseudo twist structure by continuously twisting the optically anisotropic axis can be given. Retardation films are generally transparent plastic films represented by polycarbonate, cellulose, polyarylate, polysulfone, polyacryl, polyethersulfone, norbornene, and cyclic olefin resins. Can be formed by uniaxial stretching or biaxial stretching. An optical compensatory element suitable for the present invention can be produced by laminating a plurality of these films so that each optically anisotropic axis is slightly shifted and a twist angle is provided.

In the optical compensatory element constituting the present invention, it is preferable that the dispersion of birefringence varies depending on the wavelength, similarly to the birefringence Δη of the liquid crystal substance used in the liquid crystal cell. The birefringence of the optical compensator at wavelengths λ = 450 nm and f = 590 nm (hereinafter referred to as “△ n ₂ (450)” and “Δη ₂ (590)”, respectively). double the relative refractive chromatic dispersion shed ₂

2 = Δ η ₂ (4 5 0) / Δ η ₂ (5 9 0)

Is defined. The liquid crystal material ₂ is the same if the liquid crystal materials are exactly the same, but may be the same even if different liquid crystal materials are used. In the present invention, it can be said that it is preferable that ₂ = 1.11 to 1.40 in combination with the above-described liquid crystal cell.

That is, in the transflective liquid crystal display element of the present invention, the birefringent wavelength dispersion a! And the birefringence wavelength dispersion _{2 of the} optical compensator,

 α! = 1.01 ~ 1.35

HI ₂ = 1.11-1.40

By setting the range, the transflective liquid crystal display device having an achromatic color and high-contrast reflective display characteristics can be provided.

Further, setting the birefringence chromatic dispersion value so as to satisfy 0 ^ <{ ₂ } is particularly preferable since a more remarkable achromatic and high contrast reflective display characteristic can be achieved. .

Further, the optical compensating element constituting the present invention may have a temperature compensating effect in which the product (Δη ₂ · d ₂ ) of the birefringence Δη ₂ and the thickness d ₂ of the optically anisotropic body changes with temperature. By using such an optical compensating element, it is possible to provide a reflection type liquid crystal display element in which color development hardly fluctuates even when the ambient temperature changes, and which can perform good monochrome display. Become. In this case, change with temperature in .DELTA..eta ₂ · d ₂ is to be substantially equal to the change due to the temperature of the product · d of birefringence .DELTA..eta i and the thickness d of the liquid crystal material layer in the liquid crystal cell used for driving desirable.

In the transflective liquid crystal display device of the present invention, the twist angle θ ₂ of the slow axis of the optical compensation element from the side of the linear polarizing plate to the side of the semi-transmissive reflecting plate (circular polarizing plate) is not less than 122 °. It is preferably in the range of not more than 150 degrees. The product (Zin ₂ · d ₂ ) of the refractive index anisotropy ηη ₂ of the optical compensator and the thickness d ₂ of the optical compensator may be in the range of 550 nm to 850 nm. preferable. In this way, by setting θ ₂ and と し i to values in specific ranges, and An i · di and An ₂ · d ₂ to values in specific ranges, good contrast characteristics can be obtained. Can be realized.

Further in the semi-transmission type liquid crystal display device of the present invention, hii _{"2, Θ Θ 2, Δη} ! D! S Δη 2 In addition to restricting d ₂ to a specific range, the angle 0 ₃ from the absorption axis of the linear polarizer to the slow axis on the surface of the optically complementary element on the side of the linearly polarized light S By adjusting the angle θ ₄ from the absorption axis of the linear polarizing plate to the alignment direction on the surface of the liquid crystal material layer on the side of the linear polarizing plate as described below, it is possible to realize less coloration and good contrast. Is possible.

0 ₃ = 0 ~ 10 40 ° or + 90 ~ 10 130 °

θ ₄ = 0 to 10 40 ° or +90 to + 130 °

In particular, the angle 0 _4, arranged range of + 9 0 tens 1 3 0 ° when Ru between the optical compensation element is a linearly polarizing plate and the liquid crystal material layer, also the optical compensation element is a liquid crystal material layer and the semi When it is disposed between the transmission and reflection plates, it is more preferable that the angle be in the range of 0 to + 40 °.

 The semi-transmissive reflection plate constituting the present invention is a reflection plate having a function of partially transmitting light, and is disposed between the liquid crystal material layer and a circularly polarizing plate described later. For example, it can be disposed on a transparent substrate on the side of a circularly polarizing plate in a liquid crystal cell, and can be disposed in a liquid crystal cell as in the case of the above-described linearly polarizing plate. When the transflective plate is provided in the liquid crystal cell, the transflective plate can also have a function as an electrode of the liquid crystal cell.

There is no particular limitation on the transflector, aluminum, silver, gold, chromium, platinum, copper And the like, an alloy containing them, an oxide such as magnesium oxide, a dielectric multilayer film, or a combination thereof. As these transflective plates, those which partially transmit light by performing processing such as controlling the thickness of the reflective layer and providing holes / slits are used. Further, the shape of the transflective plate may be a flat surface or a curved surface, or may be a surface having a diffuse reflection property by processing a surface shape such as an uneven shape.

 The circularly polarizing plate constituting the present invention is not particularly limited as long as it can generate substantially circularly polarized light in the visible light region or can generate elliptically polarized light close to substantially circularly polarized light. It is arranged on the opposite side of the material layer from the installation side of the linear polarizing plate. As the ellipticity at a wavelength λ = 550 nm of the circularly polarizing plate, when a circularly polarizing plate having an ellipticity close to 1 is used, it is possible to provide a transmission display with an emphasis on contrast. As the size becomes smaller, a transmissive display that emphasizes brightness can be obtained. An ellipticity of 0.5 or more is desirable for transmissive display, and more preferably 0.6 or more. If the ellipticity is less than 0.5, sufficient contrast may not be obtained.

 As the circularly polarizing plate, a circularly polarizing plate including the above-described linearly polarizing plate and the optically anisotropic element is preferable in the present invention. As the linear polarizing plate used for the circular polarizing plate, a polarizing film of the same type as the linear polarizing plate provided on the opposite side of the liquid crystal material layer from the circular polarizing plate can be used. Further, as a linear polarizing plate constituting the circular polarizing plate, a reflective polarizing film can be used. The optically anisotropic element is an element that generates a phase difference of approximately (2n + 1) -4 wavelengths (where n is an integer of 0 or more) in the visible light region, that is, linearly polarized light is substantially circularly polarized. Any element capable of converting light or elliptically polarized light close to substantially circularly polarized light can be used without any limitation. Above all, as an element that generates a phase difference of approximately (2n + 1) / 4 wavelengths in the visible light range, especially when n = 0 or 1, that is, a phase difference of approximately 1/4 wavelength or approximately 3/4 wavelength It can be said that an element which causes the above is desirable for realizing a good transmissive display.

An optically anisotropic element that generates a phase difference of approximately (2n + 1) / 4 wavelengths (where n is an integer of 0 or more) in the visible light region is optically uniaxial or biaxial. Refraction Examples thereof include an optically anisotropic element having a refractive index structure, an optically anisotropic element having a twisted structure, and a combination thereof. Examples of the optically anisotropic element having an optically uniaxial or biaxial refractive index structure include polycarbonate, cellulose, polyarylate, polysulfone, polyacryl, polyethersulfone, and norbornene. Film formed by uniaxially or biaxially stretching a transparent plastic film typified by a resin or a cyclic olefin resin, and a retardation film formed by nematically aligning a liquid crystal material. Can be. Examples of these optically anisotropic elements having a uniaxial or biaxial refractive index structure include a quarter-wave plate, a quarter-wave plate, and a quarter-wave plate manufactured from the above materials. There is a broadband quarter-wave plate produced by combining a half-wave plate.

 Examples of the optically anisotropic element having a twisted structure include a twist-aligned liquid crystal cell itself, a liquid crystal film, or a laminate of a retardation film. As the paste-aligned liquid crystal cell itself, the liquid crystal film, or the laminate of the retardation film shown here, those manufactured in the same manner as the above-described optical compensator can be used.

 These optically anisotropic elements, which have a temperature compensation effect similarly to the optical compensating element, can be preferably used.

In the circularly polarizing plate constituting the present invention, it is particularly preferable that the optically anisotropic element which is a component of the circularly polarizing plate has a twisted structure like the optical compensating element. As an optically anisotropic element having such a twisted structure, the product (An ₃ ′ d ₃ ) of the birefringence △ n ₃ and the thickness d ₃ (nm) at a wavelength λ = 550 ηπι is 140 nm or 4 and at 00 nm or less, and it is desirable in view of the circular polarization characteristic torsion angle theta ₆ is not more than 8 5 ° 30 degrees or more as an absolute value. Further, it can be said that an optically anisotropic element satisfying any one of the following conditions exhibits particularly good circularly polarized light characteristics in combination with the above-mentioned linear polarizing plate.

(1) An ₃ 'd ₃ is less than 1 75 nm or more 1 5 5 nm, twist angle theta ₆ is less than 5 0 degrees 40 degrees as an absolute value.

(2) An ₃ d ₃ is not less than 176 nm and not more than 2 16 nm, and torsion angle 0 ₆ is absolute The value is between 58 degrees and 70 degrees.

(3) Δn ₃ · d ₃ is not less than 230 nm and not more than 270 nm, and the torsion angle Q ₆ is not less than 70 degrees and not more than 80 degrees as an absolute value.

 Although there are two directions of twist, it is desirable to appropriately set the twist direction according to required display characteristics, liquid crystal cell parameters, and the like. Usually, when the direction of the twist is opposite to that of the liquid crystal cell, good transmissive display characteristics can be obtained.

 In the transflective liquid crystal display device of the present invention, a light diffusion layer can be further provided between the linear polarizer and the transflector. In particular, when the transflective plate is a specular reflection type, it is preferable to provide a light diffusing layer in reflection display.

 The light diffusion layer here is not particularly limited as long as it has a property of diffusing parallel light isotropically or anisotropically. For example, one having two or more types of regions and having a difference in refractive index between the regions, or one having an uneven surface shape can be used. Examples of the above-mentioned two or more regions having a refractive index difference between the regions include those in which particles having a refractive index different from that of the matrix are dispersed in a matrix. The light diffusion layer itself may have adhesiveness.

 Although the thickness of the light diffusion layer is not particularly limited, it is usually desirable that the thickness be 10 / m or more and 500 / m or less. Further, the total light transmittance of the light diffusion layer is preferably 50% or more, and particularly preferably 70% or more. Further, the haze value of the light-diffusing layer is usually from 10 to 95%, preferably from 40 to 90%, and more preferably from 60 to 90%.

The reflection type liquid crystal display device of the present invention includes a liquid crystal cell, a linear polarizing plate, an optical compensator, a semi-transmissive reflecting plate, and a circular polarizing plate as essential components, and further includes a light diffusion layer as necessary. is there. In addition to these, other components may be provided. Specifically, for example, by further providing a color filter, a color transflective liquid crystal display element capable of multi-color or full-color display with high color purity can be obtained. In addition, if necessary, a backlight, front light, light control film, light guide plate, prism sheet, anti-reflection layer, anti-glare treatment layer, adhesive layer, adhesive layer, hard coat layer, etc. will be provided. It is also possible. [Industrial applicability]

 The transflective liquid crystal display device of the present invention can provide a bright display for both the reflective display and the transmissive display, and can realize a display with high contrast and good color, which is significantly larger than the conventional transflective liquid crystal display device. High display quality can be obtained.

[Example]

 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

 In this example, an experiment was performed by preparing an element with the counterclockwise direction being 10 and the clockwise direction being 1 from the linear polarizing plate side to the transflective plate side. However, the same result can be obtained by conducting the same experiment with the clockwise direction set to 10 and the counterclockwise direction set to 1 from the linear polarizing plate side to the transflective plate side. In addition, the determination value (= Δη · d) in this embodiment is a value at a wavelength λ = 55 O nm unless otherwise specified. Example 1

An STN-type transflective liquid crystal display element schematically shown in FIG. 1 was produced. As shown in FIG. 1, the liquid crystal cell 3 includes a pair of transparent substrates 3D opposed to each other, and a semi-transmissive reflector 3 provided on the surface of the transparent substrate opposite to the display surface (lower side in FIG. 1). C, an electrode 3B provided on the inner surface thereof, and an alignment film 3F printed and formed thereon and subjected to an alignment treatment. A liquid crystal material is sealed in a space defined by the alignment film 3F and a sealant 3E formed by printing and forming around the substrate, and a liquid crystal material layer 3A is formed. By using ZLI — 229 3 (manufactured by Merck) as the liquid crystal material, the liquid crystal material layer 3A is oriented in a predetermined direction by adjusting the orientation direction of the orientation film 3F. = +250 degrees twisted. The product t of the birefringence An 屈折 of the liquid crystal material in the liquid crystal cell 3 and the thickness di of the liquid crystal material layer 3A was approximately 800 nm. The birefringence chromatic dispersion (^ A, (450) / An, (590)) of ZLI-2229 was 1.10. A linear polarizer 1 (SR1862AP manufactured by Sumitomo Chemical Co., Ltd.) is arranged on the display surface side (upper side of the figure) of the liquid crystal cell 3, and a twisted structure is provided between the linear polarizer 1 and the liquid crystal cell 3. The optical compensator 2 having the structure shown in FIG. An ₂ · d ₂ of the optical compensation element 2 is substantially 6 7 0 nm, it Gillet angle theta ₂ = - a 1 9 0 degree, and a non-birefringent wavelength dispersion ₂ = 1 1 5.. At this time, the angle from the absorption axis of the linear polarizing plate 1 to the alignment axis on the surface of the optical compensator '2 on the side of the linear polarizing plate of the optical compensator 側₃ = +20 degrees, The angle of の to the orientation direction on the surface on the side of the linear polarizing plate was set to S ₄ = + 105 degrees.

Also, the circular polarizing plate 4 composed of a linear polarizing plate 4B (SR1862AP manufactured by Sumitomo Chemical Co., Ltd.) and an optically anisotropic element 4A having a twisted structure is viewed from the display side. Placed behind the Δη ₂ · d ₂ of the optical anisotropic element 4 A having a twisted structure substantially 1 9 0 nm, the twist angle 0 ₆ = - was 6 5 degrees. At this time, the angle from the absorption axis of the linear polarizer 1 to the alignment axis on the liquid crystal cell side surface of the optically anisotropic element 4A Θ ₅ = +35 degrees. The angle of 4 B to the absorption axis was set to 0 ₇ = +60 degrees. When this axis arrangement was used, the ellipticity of the four circular polarizers at a wavelength of 550 nm was measured with an ellipsometer (DVA-36 VWL D manufactured by Mizojiri Optical Industrial Co., Ltd.). Was 4.

 Furthermore, a light diffusion layer 5 is formed between the optical compensator 2 and the liquid crystal cell 3 by dispersing substantially spherical fine particles having a refractive index different from that of a matrix in a matrix made of an acrylic adhesive. An adhesive layer having a diffusion characteristic (total light transmittance 90%, haze value 80%) is arranged, and the linear polarizing plate 1 and the optical compensator 2 and the liquid crystal cell 3 and the circular polarizing plate 4 An ordinary transparent pressure-sensitive adhesive layer was disposed.

The relationship between the angle 0 i~0 ₇ in the components of the S TN semi-transmissive liquid crystal display device shown in FIG. FIG. 2 shows the axial arrangement of each component when viewing the transflective liquid crystal display element from the display side.

In FIG. 2, the orientation direction 31 of the liquid crystal material layer 3A on the surface of the linear polarizing plate 1 and the orientation direction 32 of the liquid crystal material layer 3A on the surface of the circular polarizer 4 form an angle 0i. I have. Optical compensator 2, the direction 2 1 orientation axis in linear polarizer 1 side on the surface, to the direction 2 2 axis of orientation on the plane of the liquid crystal cell Le side, an angle theta _2. Orientation axis direction 4 1 on surface of linear polarizing plate 1 of optically anisotropic element 4 A, and linear polarizing plate 4 B side The orientation 4 2 axis of orientation on a surface at an angle S _6. In addition, the absorption axis 11 of the linear polarizing plate 1 and the direction 21 of the alignment axis on the surface of the optical compensator 2 on the side of the linear polarizing plate 1 form an angle 0 _3, and the absorption axis 1 1 of the linear polarizing plate 1 When, the orientation direction 3 1 on the plane of the linear polarizer 1 side of the liquid crystal material layer 3 a at an angle theta _4. The alignment direction 4 1 on the liquid crystal cell side of the optical anisotropic element 4 A in circular polarizer 4, without the absorption axis 1 1 and the angle theta ₅ straight line polarizing plate 1, the absorption of the linearly polarizing plate 4 beta axis 4 3 forms an absorption axis 1 1 and the angle theta ₇ linear polarizer 1.

 When a driving voltage is applied to the electrode 3 from a driving circuit (not shown) to the above liquid crystal display element (not shown), the backlight is not lit by arranging a knock light and a knock light. Examination of the optical characteristics in (reflection mode) and lighting (transmission mode) revealed bright and high contrast in both reflection mode and transmission mode. In this embodiment, the experiment was performed without any color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 2

Ari i of liquid crystal cell 3 is approximately 880 nm, An ₂ and d ₂ of optical compensator ₂ are approximately 74 nm, birefringence wavelength dispersion is ₂ = 1.13, and optically anisotropic element 4 A and the an ₃ · d ₃ substantially 1 6 5 nm, theta = + 2 4 0 °, theta ₂ = _ 1 8 0 degree, 0 ₃ = + 1 5 °, 0 ₄ = + 1 1 0 degrees, S ₅ = + 30 degrees, θ ₆ = −45 degrees, and θ ₇ = + 60 degrees, and a liquid crystal display device similar to that of Example 1 was produced. With this axis arrangement, the ellipticity at a wavelength of 部 = 550 nm of four parts of the circularly polarizing plate was measured with an ellipsometer-1 (DVA-36 VWL D, manufactured by Mizojiri Optical Co., Ltd.). Was 3.

When a drive voltage is applied to the above liquid crystal display element from a drive circuit (not shown) to the electrode 3B (drive at 1/100 duty, optimal bias), and the non-light is off (reflection mode) Examination of the optical characteristics when the LED was lit and in the transmission mode (transmission mode) revealed that the display was bright and had high contrast in both the reflection mode and the transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 3.

Substantially 840 nm to Δπι · di of the liquid crystal cell 3, approximately 7 1 0 nm to An ₂ · d ₂ of the optical compensation element 2, and the birefringence wavelength dispersion shed ₂ = 1. 1 3, An optical anisotropic element 4 A ₃ · d ₃ is approximately 250 nm, S i + SAO degree, θ ₂ = _ 180 degrees, θ ₃ = + 15 degrees, θ ₄ = + 110 degrees, θ ₅ = + 30 The liquid crystal display device was manufactured in the same manner as in Example 1 except that the temperature was set at 0 6 = −75 ° and θ ₇ = + 60 °. With this axis arrangement, the ellipticity at a wavelength of 550 nm for four parts of the circularly polarizing plate was measured with an ellipsometer (DVA-36 VWLD, manufactured by Mizojiri Optical Co., Ltd.). Was 3.

 A drive circuit (not shown) applies a drive voltage to the above-mentioned liquid crystal display element to the electrode 3B (drive at 1/100 duty, optimal bias), and when the non-smoking is not lit (reflection mode) and Inspection of the optical characteristics during lighting (transmission mode) revealed that the display was bright and high-contrast in both reflection mode and transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 4

The liquid crystal cell 3 has Δη ι · di of about 85 O nm, the optical compensation element 2 has Zn ₂ · d _{2 of} about 690 nm, and the birefringence wavelength dispersion ₂ = 1.15. 4 .DELTA..eta ₃ · d ₃ of a was approximately 3 7 0 nm, theta丄= + 2 5 ◦ degree, 0 ₂ = - 1 9 0 °, 3 ₃ = + 1 5 °, 0 ₄ = + 1 00 degrees, 6> ₅ = −20 degrees, θ ₆ = −45 degrees, and θ ₇ = + 50 degrees, and a liquid crystal display device similar to that of Example 1 was produced. With this axis arrangement, the ellipticity of four circular polarizers at 550 nm was measured with an ellipsometer (DVA-36 VWL D, manufactured by Mizojiri Optical Co., Ltd.). 90.

When a drive voltage is applied to the electrode 3B from the drive circuit (not shown) to the above-mentioned liquid crystal display element (driving at 1/100 duty, optimum bias), and the non-light is turned off (reflection mode) Inspection of the optical characteristics in the) and lighting (transmission mode) revealed bright and high-contrast displays in both the reflection mode and the transmission mode. In particular, it was found that the film had good brightness and hue in the transmission mode. In this embodiment, the color The experiment was conducted without a filter, but if a color filter is provided in the liquid crystal cell, good multi-color or full-color display can be achieved. Example 5

The liquid crystal cell 3 has Δη ι · di of approximately 850 nm, the optical compensator 2 has An ₂ and d ₂ of approximately 690 nm, and the birefringence wavelength dispersion ₂ = 1.15. A ₃ · d ₃ of A is assumed to be approximately 280 nm, 0 度 = + 25 °, S ₂ = 19 °, S ₃ = + 15 °, 0 ₄ = + 100 °, S ₅ = - 5 °, theta ₆ = - 6 0 degrees, except for using 0 ₇ = + 40 °, was produced in the same manner as the liquid crystal display device as in example 1. With this axis arrangement, the ellipticity of the four circular polarizers at a wavelength of 550 nm was measured with an ellipsometer (DVA-36 VWLD manufactured by Mizojiri Optical Industry Co., Ltd.) to be 0.81. Was.

 A drive voltage is applied to the above liquid crystal display element from a drive circuit (not shown) to the electrode 3B (1/100 duty, drive with the optimum bias), and the non-light is turned off (reflection mode). Examination of the optical characteristics when the lamp was lit and in the transmission mode (transmission mode) revealed bright and high contrast displays in both the reflection mode and the transmission mode. In particular, it was found that the film had good brightness and hue in the transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 6

Approximately 8 5 0 nm to [Delta] [gamma] ^ · of the liquid crystal cell 3, substantially 6 9 0 nm to .DELTA..eta ₂ · d ₂ of the optical compensation element 2, and the birefringence wavelength dispersion _"2 = 1.1 5, the optical anisotropic element 4 A An ₃ · d ₃ is approximately 340 nm, 0 丄 = + 25 °, 0 ₂ = —190 °, 0 ₃ = + 15 °, 0 ₄ = + 100 °, 0 ₅ = + 5 degrees, θ ₆ = −60 degrees, Θ ₇ = + 65 degrees, and a liquid crystal display element similar to that of Example 1 was produced. With this axis arrangement, the ellipticity at the wavelength of 550 nm of the four portions of the circularly polarizing plate was measured with an ellipsometer (DVA-36 VWLD manufactured by Mizojiri Optical Industry Co., Ltd.). there were.

When a drive voltage is applied to the above liquid crystal display element from a drive circuit (not shown) to the electrode 3B (driven at 1 / 1◦0 duty, optimal bias), and the non-light is turned off (the Examination of the optical characteristics in the firing mode and the lighting mode (transmission mode) revealed bright and high-contrast displays in both the reflection mode and the transmission mode. In particular, it was found that the film had good brightness and hue in the transmission mode. In this embodiment, the experiment was performed without any color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full color display can be achieved. Example 7

The liquid crystal cell 3 has An ^ di of about 850 nm, the optical compensator 2 has An ₂ and d _{2 of} about 690 nm, the birefringence wavelength dispersion ₂ = 1.15, and the optically anisotropic element 4 A and the an ₃ · d ₃ substantially 1 9 0 nm, theta丄= + 2 5 0 °, theta ₂ = - 1 9 0 °, theta ₃ = + 1 5 °, theta ₄ = + 1 0 0 degree, theta ₅ = + 5 0 °, 0 ₆ = -. 7 5 degrees, except for using theta ₇ = + 7 0 degrees, was produced in the same manner as the liquid crystal display device as in example 1. With this axis arrangement, the ellipticity at 4 = 550 nm was measured with an ellipsometer (DV A-36 VWL D, manufactured by Mizojiri Kogakusho Co., Ltd.). 8 was 6.

 A drive circuit (not shown) applies a drive voltage to the above-mentioned liquid crystal display element to the electrode 3B (drive at 1Z100 duty, optimal bias), and the knock light is turned off (reflection mode) and turned on (reflection mode). When the optical characteristics of the transmission mode were examined, bright and high-contrast display was possible in both the reflection mode and the transmission mode. In particular, it was found that the film had good brightness and hue in the transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in a liquid crystal cell, a good multi-color or full-color display can be performed. Example 8

Approximately 8 5 0 nm to Ani 'di of the liquid crystal cell 3, and the An ₂ · d ₂ of the optical compensation element 2 substantially 6 9 0 nm, and ₂ = 1.1 5 non-birefringent wavelength dispersion, the optical anisotropic element 4 A and the .DELTA..eta ₃ · d ₃ approximately 3 2 0 nm, Θ = + 2 5 0 °, θ ₂ = - 1 9 0 °, ₃ = + 1 5 °, theta ₄ = + 1 0 0 degree, theta ₅ = 0 °, 0 ₆ = - 7 5 degrees, except for using theta ₇ = + 4 0 °, to produce a liquid crystal display device as in example 1. With this axis arrangement, the ellipticity of the four circular polarizers at the wavelength of 550 nm is determined by the ellipsometer (Mizojiri Optical Industrial Co., Ltd.) It was 0.84 when measured by DVA-36 VWL D).

 A drive voltage is applied to the electrode 3B from the drive circuit (not shown) to the above liquid crystal display element (driving at 1/100 duty, optimum bias), and when the backlight is not lit (reflection mode) and lit Examination of the optical characteristics of the transmission mode (transmission mode) revealed that both the reflection mode and the transmission mode provided bright, high-contrast displays. In particular, it was found that the film had good brightness and hue in the transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 9

The liquid crystal cell 3 has Δη ι · di of approximately 850 nm, the optical compensator 2 has An ₂ and d ₂ of approximately 690 nm, and the birefringence wavelength dispersion α ₂ = 1.15. An ₃ -d ₃ of Α is approximately 220 nm, Θ 丄 = + 25 °, 0 ₂ = —190 °, 0 ₃ = + 15 °, θ ₄ = + 100 °, 0 ₅ = 1 5 degrees, 0 ₆ = _ 6 0 degrees, except that 0 ₇ = + 5 is set to 0 degrees, to produce a liquid crystal display device as in example 1. With this axis arrangement, the ellipticity of the four circular polarizers at a wavelength of 550 nm was measured with an ellipsometer (DVA-36 VWL D, manufactured by Mizojiri Optical Industry Co., Ltd.). Met.

 When a driving voltage is applied to the above liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimum bias), and the non-light is turned off (reflection mode) Inspection of the optical characteristics in the) and lighting (transmission mode) revealed bright and high-contrast displays in both the reflection mode and the transmission mode. In particular, it was found that the film had good brightness and hue in the transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full color display can be achieved. Example 1 ◦

Approximately 9 5 0 nm to .DELTA..eta · d of the liquid crystal cell 3, approximately 8 1 0 nm to An ₂ · d ₂ of the optical compensation element 2, the birefringence wavelength dispersion shed ₂ = 1.1 5 and then, the optical anisotropic element 4 A Let An ₃ · d ₃ be approximately 190 nm, Θ, = + 25 °, θ. = —190 degrees, 0 ₃ = +20 degrees, A liquid crystal display device similar to that of Example 1 was produced except that θ ₄ = + 100 °, θ ₅ = 20 °, θ ₆ = −65 °, and θ ₇ = + 55 °. With this axis arrangement, the ellipticity of the four circular polarizers at a wavelength of 550 nm was measured with an ellipsometer (DVA-36 VWLD, manufactured by Mizojiri Optical Industrial Co., Ltd.) at 0.69. there were.

 A drive voltage is applied to the above liquid crystal display element from a drive circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimum bias), and when the non-smoking is not lit (reflection mode) and Inspection of the optical characteristics during lighting (transmission mode) revealed bright, high-contrast displays in both reflection and transmission modes. In particular, it was found that the film had good brightness and hue in the transmission mode. In the present embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 1 1

The Arii · di of the liquid crystal cell 3 was substantially 8 0 0 nm, the .DELTA..eta ₂ · d ₂ of the optical compensation element 2 substantially 6 5 0 nm, the birefringence wavelength dispersion α ₂ = 1. 1 5, the optical anisotropic element 4 Alpha and the an ₃ · d ₃ substantially 1 9 0 nm, theta丄= + 2 5 0 °, theta ₂ = - 1 9 0 °, 0 ₃ = + 1 5 °, theta ₄ = + 1 0 0 degree, theta ₅ = - 1 0 °, 0 ₆ = + 6 5 degrees, except for using theta ₇ = + 5 5 degrees, was produced in the same manner as the liquid crystal display device as in example 1. With this axis arrangement, the ellipticity at 550 nm of the wavelength of four parts of the circularly polarizing plate was measured with an ellipsometer (DVA-36 VWLD manufactured by Mizojiri Optical Co., Ltd.). Met.

 A drive circuit (not shown) applies a drive voltage to the above-mentioned liquid crystal display element to the electrode 3B (drive at 1/100 duty, optimal bias), and when the non-light is not lit (reflection mode) and Examination of the optical characteristics in the lighting mode (transmission mode) revealed bright and high-contrast displays in both the reflection mode and the transmission mode. In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be performed. Example 1 2

As the liquid crystal material of liquid crystal cell 3, ZLI—5 049 (manufactured by Merck), and the An ^ c substantially 7 9 0 nm, the optical compensation element 2 of delta 11 ₂ '(1 ₂ substantially 6 5 0 11111, non-birefringent wavelength dispersion and ₂ = 1.2 4 , An ₃ ′ d ₃ of the optically anisotropic element 4 A is approximately 190 nm, and S i + SSO degree, θ ₂ = −190 degrees, θ ₃ = + 15 degrees, θ ₄ = + 10 0 °, theta ₅ = 2 0 °, θ ₆ = -. ₆ 5 degrees, 0 ₇ = + 5 except for using 5 degrees, was produced in the same manner as the liquid crystal display device of example 1 when this shaft arrangement, the circle The ellipticity of the four portions of the polarizing plate at a wavelength λ = 550 nm was measured with an ellipsometer (DVA-36 VWLD manufactured by Mizojiri Optical Industrial Co., Ltd.) and found to be 0.69. Then, a driving voltage is applied to the electrode 3B from a driving circuit (not shown) (110 duty, driving with an optimum bias), and the backlight is turned off (reflection mode) and turned on (transmission mode). When the optical characteristics were examined, the reflection mode and transmission In this example, it was found that the display had good brightness and hue in the transmissive mode. If a color filter is provided in the liquid crystal cell, a good multi-color or full-color display can be achieved.

As a liquid crystal material of the liquid crystal cell 3, ZLI—5049 (manufactured by Merck) having a birefringence wavelength dispersion of i = 1.21 is used, and is approximately 79 O nm, and △ 11 ₂ ′ (1 ₂ is approximately 65 0 11111, birefringence wavelength dispersion is ₂ = 1.21, and An ₃ 'd ₃ of the optically anisotropic element 4 A is approximately 190 nm, S i + SSO degree, 0 ₂ = — Except for 190 degrees, 0 ₃ = +15 degrees, 0 ₄ = +100 degrees, 0 ₅ = 20 degrees, θ ₆ = —65 degrees, θ ₇ = +55 degrees A liquid crystal display device was produced in the same manner as in Example 1. In this axial arrangement, the ellipticity at a wavelength of 550 nm of the four portions of the circularly polarizing plate was calculated using an ellipsometer DVA-3 manufactured by Mizojiri Optical Industry Co., Ltd. 6 VWLD) was 0.69.. A drive voltage was applied from the drive circuit (not shown) to the electrode 3B to the above liquid crystal display element (1Z100 duty, optimal bias). ), When the client is not lit (reflection mode) and when lit When the optical characteristics of (transmission mode) were examined, bright and high-contrast display was possible in both the reflection mode and the transmission mode, and it was found that the display mode had good brightness and hue especially in the transmission mode. OK, color The experiment was conducted in a mode where there was no interference, but if a color filter is provided in the liquid crystal cell, excellent multi-color or full-color display can be achieved. Comparative Example 1

As the liquid crystal material of the liquid crystal cell 3, a birefringent wavelength dispersion (ZLI — 504 9 (manufactured by Merck)) with i = 1.21 is used, Δι ^ .el is approximately 790 nm, and the optical compensation element 2 △ 11 ₂ ′ (1 ₂ is approximately 65 0 11111, birefringence wavelength dispersion is ₂ = 1.10, An ₃ ′ d ₃ of the optically anisotropic element 4 A is approximately 190 nm, ^ = + 2 5 0 °, ₂ = - 1 9 0 °, 0 ₃ = + 1 5 °, theta ₄ = + 1 0 0 degree, theta ₅ = 2 0 °, 0 ₆ = - 6 5 degrees, 0 ₇ = + 5 A liquid crystal display device was prepared in the same manner as in Example 1 except that the angle was set to 5 degrees.With this axis arrangement, the ellipticity at 550 nm of the four portions of the circularly polarizing plate was measured by an ellipsometer (Mizojiri Co., Ltd.). It was 0.69 when measured with D VA-36 VWL D) manufactured by Kogaku Kogyosho Co., Ltd. A drive voltage was applied to the above-mentioned liquid crystal display element from the drive circuit (not shown) to the electrode 3B (1 / 100 duty, driving with optimal bias), when backlight is off (reflection mode) Fine lit On examination of the optical characteristics of the (transmission mode), blue black in color when the voltage off, con Trust is also lowered, it was not possible to obtain good display characteristics.

[Brief description of drawings]

 FIG. 1 is a schematic cross-sectional view showing a configuration of a liquid crystal display device manufactured in each of Examples 1 to 13 and Comparative Example 1.

 FIG. 2 is a plan view illustrating the relationship between the absorption axis of the linear polarizer, the axis of the liquid crystal cell, the optical compensator, and the axis of the circular polarizer in the liquid crystal display devices of Examples 1 to 13 and Comparative Example 1.

Claims

The scope of the claims 1. A liquid crystal cell in which a liquid crystal material layer is inserted between a pair of transparent substrates having electrodes, a linear polarizing plate, an optical compensator having a twisted structure, a semi-transmissive reflecting plate, and a circular polarizing plate. In the transflective liquid crystal display device in which the above voltage value is selected and a driving voltage is applied to the liquid crystal material layer,  The linear polarizing plate is disposed on one surface side of the liquid crystal material layer,  The circularly polarizing plate is disposed on the other surface side of the liquid crystal material layer,  The transflective plate is disposed between the liquid crystal material layer and the circularly polarizing plate,  The optical compensator is disposed between the linear polarizer and the transflector, and determines the ratio of birefringence Δη at wavelengths λ = 450 nm and λ = 590 nm to the birefringence wavelength dispersion.  α = Δ η (4 5 0) / Δ η (5 90) If you define The birefringence wavelength dispersion i of the liquid crystal material layer and the birefringence wavelength dispersion α _{2 of the} optical compensation element are! = 1.0 1 to 1.3 5  α 2-1 A transflective liquid crystal display device. 2. The birefringence chromatic dispersion i of the liquid crystal material layer and the birefringence chromatic dispersion α _{2 of the} optical compensator are:  «1 <α 2 The transflective liquid crystal display element according to claim 1, wherein the liquid crystal display element ₍ 3. The twist angle 0i of the liquid crystal molecules from the side of the linear polarizer to the side of the transflective plate in the liquid crystal material layer is in the range of +200 degrees or more and +270 degrees or less. The twist angle θ ₂ of the slow axis of the compensating element from the side of the linear polarizing plate to the side of the transflective plate is in the range of −220 degrees or more and −155 degrees or less, and the wavelength λ of the liquid crystal material layer is The product of the birefringence △ !! 1 and the thickness d 丄 at 550 nm (Δ Γ ^ · d!) Is 700 nm or more 1 The product of the birefringence An ₂ and the thickness d ₂ of the optical compensation element (An ₂ ′ d ₂ ) at 550 nm is 550 nm. 3. The transflective liquid crystal display device according to claim 1, wherein the range is at least 850 nm. 4. The method according to any one of claims 1 to 3, wherein the circularly polarizing plate comprises at least a linear polarizing plate and an optically anisotropic element, and the optically anisotropic element has a twisted structure. A transflective liquid crystal display element according to any one of the above items. 5. The product (Δη ₃ · d ₃ ) of birefringence △ n ₃ and thickness d ₃ (nm) at wavelength λ = 550 nm of the optically anisotropic element constituting the circularly polarizing plate is 1 40 nm or 4 is at 0 O nm or less, and the twist angle theta ₆ from linear polarizing plate side of the slow axis of the optical anisotropic element into circularly polarizing plate side, 3 0 degrees 8 5 degrees or less as an absolute value The transflective liquid crystal display device according to any one of claims 1 to 4, wherein the transflective liquid crystal display device is in a range. 6. The wavelength (Δη ₃ · d ₃ ) of the birefringence △ n ₃ and the thickness d ₃ (nm) at 550 nm of the optically anisotropic element constituting the circular linear polarizing plate, and the optically anisotropic element The torsion angle θ ₆ from the linear polarizing plate side to the circular polarizing plate side of the slow axis of  (1) 1 5 5 nm or more 1 Ί 5 nm or less and absolute value 40 degrees or more and 50 degrees or less, (2) 1 76 nm or more and 2 16 nm or less and absolute value of 58 degrees or more Ί 0 degree or less, (3) 230 nm or more and 2 70 nm or less and absolute value of 70 degrees or more and 80 degrees The transflective liquid crystal display device according to any one of claims 1 to 5, wherein one of the following conditions is satisfied: 7. The transflective liquid crystal display device according to claim 1, further comprising at least one light diffusion layer between the linear polarizer and the transflector.