JP2002148621A - Semitransmission type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semitransmission type liquid crystal display device which can display both in a reflection mode and in a transmission mode. SOLUTION: The device has a liquid crystal cell 3 having a liquid crystal substance inserted between a pair of transparent substrates 3D, a linearly polarizing plate 4D, an optical compensation element 4A having a twisted structure, a semitransmission reflection plate 4C and a circularly polarizing plate, and two or more voltage values are selected to apply the driving voltage on the liquid crystal substance. In this device, the linearly polarizing plate and the circularly polarizing plate are disposed in the respective face sides of the liquid crystal substance layer, the semitransmission reflection plate is disposed between the liquid crystal substance layer and the circularly polarizing plate, and the optical compensation element is disposed between the linearly polarizing plate and the semitransmission reflection plate. When the ratio of birefringence Dn at the wavelength λ=450 nm to Δn at λ=590 nm is defined as the birefringent wavelength dispersion α, the birefringent wavelength dispersion α1 of the liquid crystal material layer and the birefringent wavelength dispersion α2 of the optical compensation element range α1=1.01 to 1.35 and α2=1.11 to 1.40, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transflective liquid crystal display device capable of displaying in either a reflection mode or a transmission mode.

[0002]

2. Description of the Related Art In recent years, there is an increasing expectation that the market for a liquid crystal display device as a display of a portable information terminal device, which can make full use of its thin and lightweight characteristics, will be greatly enhanced. Since portable electronic devices are usually driven by a battery, it is important to reduce power consumption. 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 that does not need to be used at all times, can be reduced in power consumption, thinned, and lightened. Particular attention has been paid. Conventionally, as a liquid crystal display element, a TN (twisted nematic) type and an STN (super twisted nematic) type are mainly used. The 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 reflection plate is usually further disposed outside the liquid crystal cell. are doing. In the STN type liquid crystal display element, 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, a sudden change in molecular alignment due to the application of a voltage can be reflected in a change in birefringence of the liquid crystal, and an electro-optical characteristic exhibiting a sudden optical change above a threshold can be realized.

In a liquid crystal display device of the STN mode, yellow-green or dark blue may occur as a display background color due to birefringence of liquid crystal. In order to improve the coloring phenomenon, a liquid crystal cell for optical compensation 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. Thus, a liquid crystal display element configured to perform color compensation and perform a display similar to a black and white display is used as a so-called paper white type liquid crystal display element. However, in a liquid crystal display device of the STN mode, the transmittance of the polarizing plate is about 9 even when linearly polarized light is incident parallel to the polarization axis.
0%, and there is a problem that sufficient brightness cannot be obtained with the conventional configuration using two polarizing plates.
In particular, in the case of a reflection type liquid crystal display element, the backlight is not used, and the incident light passes through the polarizing plate a total of four times before exiting, so that the attenuation of the light quantity becomes a problem.

As a conventional technique for solving this problem, there is a technique described in Japanese Patent Application Laid-Open No. 2-189519 or Japanese Patent Application Laid-Open No. 6-11711. These include 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, from a reflective liquid crystal display device using a commonly used STN type liquid crystal cell to a polarizing plate on the reflecting plate side. There is disclosed a liquid crystal display element having a configuration excluding. By adopting such a configuration, the number of times that the incident light passes through the polarizing plate before the light is emitted becomes two times, and it is expected that high brightness is inevitably obtained and white display with high reflectivity is achieved. Is done. However, when a reflective liquid crystal display device having such a configuration is formed, each layer such as a phase difference plate or the like is formed due to a low degree of structural freedom in that a single polarizing plate serves as polarized light before and after reflection. Is difficult to provide so as to provide a good high-contrast display.

Further, these reflection type liquid crystal display elements include:
Normally, display is performed by using external light, and therefore, when used in a dark environment, there is a disadvantage that the display becomes invisible or difficult to see. As a technique for solving this problem, as described in Japanese Patent Application Laid-Open No. H10-206846, in a reflection type liquid crystal display element having a single polarizing plate, a half-light having a property of transmitting a part of incident light instead of the reflection plate is used. A transflective liquid crystal display element using a transflector 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 can be used as a transmission type (transmission mode) with the backlight lit in a dark environment.
However, in this transflective liquid crystal display element, it is necessary to drive the reflection mode and the transmission mode in association with each other,
Further, in the transmission mode, there is a problem that an optical design for performing good display is more complicated, such as further requiring a polarizing plate and a retardation plate between the transflective plate and the backlight.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transflective liquid crystal display device having a bright display, a high contrast, a good color, and an easy optical design for both reflective display and transmissive display. It is in.

[0007]

That is, the first aspect of the present invention is as follows.
Comprises a liquid crystal cell in which a layer of a liquid crystal substance is inserted into a pair of transparent substrates provided with electrodes, a linear polarizing plate, an optical compensation element having a twisted structure, a semi-transmissive reflecting plate, and a circular polarizing plate.
In a transflective liquid crystal display element in which a voltage value equal to or greater than a 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, and the optical compensator is disposed between the linearly polarizing plate and the half-polarized light plate. When the ratio of the birefringence Δn at wavelengths λ = 450 nm and λ = 590 nm is defined as birefringence wavelength dispersion αα = Δn (450) / Δn (590), the liquid crystal material layer is birefringent. Wherein the wavelength dispersion α ₁ and the birefringence wavelength dispersion α _{2 of the} optical compensation element are in the range of α ₁ = 1.01 to 1.35 α ₂ = 1.11 to 1.40. The present invention relates to a liquid crystal display device.

A second aspect of the present invention is that the liquid crystal material layer has
Liquid crystal molecules from the linear polarizer to the transflector
Torsion angle θ₁Is in the range from +200 degrees to +270 degrees
And a half of the slow axis of the optical compensation element from the side of the linear polarizing plate.
Torsion angle θ to transmission / reflection plate side _TwoIs -220 degrees or higher-1
55 degrees or less, and the wavelength λ = 5 of the liquid crystal material layer.
Birefringence at 50 nm Δn₁And thickness d₁With (△ n₁
・ D₁) Is in the range of 700 nm or more and 1000 nm or less.
The wavelength of the optical compensator at λ = 550 nm.
Refraction △ n_TwoAnd the thickness d of the optical compensation element_TwoWith (△ n_Two
・ D_Two) Is in the range of 550 nm to 850 nm.
The transflective liquid crystal display element described above,
I do.

A third aspect of the present invention is that the circularly polarizing plate comprises at least a linearly polarizing plate and an optically anisotropic element,
In addition, the present invention relates to the above-mentioned transflective liquid crystal display element, wherein the optically anisotropic element has a twisted structure.

A fourth aspect of the present invention is that the product (Δn ₃ · d ₃ ) of the birefringence Δn ₃ and the thickness d ₃ (nm) at a wavelength λ = 550 nm of the optically anisotropic element constituting the circularly polarizing plate is: 140
torsion 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 in a range of 30 degrees or more and 85 degrees or less as an absolute value.

A fifth aspect of the present invention is a product (Δn ₃ · d ₃ ) of the birefringence Δn ₃ and the thickness d ₃ (nm) at a wavelength λ = 550 nm of the optically anisotropic element constituting the circularly polarizing plate, and The twist angle θ ₆ of the slow axis of the optically anisotropic element from the side of the linear polarizer to the side of the circular polarizer is (1) 155 nm or more and 175 nm or less and 40 to 50 degrees in absolute value, and (2) 176.
nm or more and 216 nm or less and 58 degrees or more as an absolute value 7
(3) The transflective liquid crystal display element according to the above, which satisfies any condition of not less than 0 degree and (3) not less than 230 nm and not more than 270 nm and an absolute value of not less than 70 degree and not more than 80 degrees.

A sixth aspect of the present invention relates to the above-mentioned transflective liquid crystal display device, further comprising at least one light diffusion layer between the linear polarizing plate and the transflector.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 constituting the present invention has a pair of transparent substrates provided with electrodes and a layer of a liquid crystal material inserted between them. As the transparent substrate, a substrate that aligns the liquid crystal material in a specific alignment 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 such that the alignment directions are in a twisted relationship, and forming a layer of a liquid crystal material between the transparent substrates, a layer of the liquid crystal material is formed. , Can give a specific twist angle. Also,
The electrode of the liquid crystal cell can be usually provided on the surface of the transparent substrate in contact with the layer of the liquid crystal substance, and when a transparent substrate having an alignment film is used, it can be provided between the transparent substrate and the alignment film. it can. 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 device of the present invention,
A driving voltage is applied to the liquid crystal material layer by selecting two or more voltage values. 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. . Thereby, 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 effects of the present invention by setting the birefringence wavelength dispersion alpha ₂ of the optical compensation element to be described below birefringence wavelength dispersion alpha ₁ of the liquid crystal material used in a liquid crystal cell to be described later to a particular numerical range It is possible to obtain. The birefringence (= refractive index anisotropy) Δn of a liquid crystal material used for a liquid crystal cell generally has a wavelength λ.
(Nm), and its characteristics generally have a negative tendency with respect to the wavelength λ. That is, the ratio of the birefringence (hereinafter, referred to as “Δn ₁ (450)” and “Δn ₁ (590),” respectively) of the liquid crystal material at wavelengths λ = 450 nm and λ = 590 nm is referred to as birefringence wavelength dispersion. The birefringence wavelength dispersion α ₁ of the liquid crystal material in the liquid crystal cell constituting the present invention is represented by α ₁ = Δ
When defined as n ₁ (450) / Δn ₁ (590), usually α
₁ > 1. α ₁ 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, a more remarkable effect of the present invention can be exhibited when α ₁ = 1.01 to 1.35 from the relationship with the birefringence wavelength dispersion α _{2 of} the optical compensating element described later.

The twist angle θ ₁ of the liquid crystal material molecules from the side of the linear polarizer to the side of the transflector (circular polarizer) in the liquid crystal material layer in the liquid crystal cell is usually + 200 ° to + 270 °.
Is desirably 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 steep change in reflectance and transmittance. If it exceeds + 270 °, hysteresis tends to occur. In the present specification, the positive and negative directions of the angle mean the directions of rotation of the relative angles, and the clockwise direction when the counterclockwise direction from the linear polarizing plate toward the circular polarizing plate is +. The direction is-, and conversely, if the clockwise direction is +, the counterclockwise direction is-. However, any case of + is included in the scope of the present invention, and equivalent effects can be obtained. Further, the product of the refractive index anisotropy Δn ₁ of the liquid crystal material layer in the liquid crystal cell and the thickness d ₁ (Δn ₁
D ₁ ) is preferably in the range of 700 nm or more and 1000 nm or less. If it is less than 700 nm, the change in the state of the liquid crystal when a voltage is applied is small.

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 or the back surface of the liquid crystal cell, in other words, it is arranged on the surface of the transparent substrate which is not the liquid crystal material layer interface side of one transparent substrate. A linear polarizing plate may 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 can 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. Specifically, polyvinyl alcohol (PVA) or partially acetalized PV
A, such as a PVA-based polarizing film, a hydrophilic polymer film made of a partially saponified ethylene-vinyl acetate copolymer, and the like, which is stretched by adsorbing iodine and / or a dichroic dye, dehydration of PVA A polarizing film made of a processed product or a polyene oriented film such as a dehydrochlorinated product of polyvinyl chloride can be used. The linear polarizing plate may be used alone or a polarizing film provided with a transparent protective layer or the like on one or both sides of the polarizing film for the purpose of improving strength, improving moisture resistance, improving heat resistance, and the like. Is also good. Examples of the transparent protective layer include those obtained by laminating a transparent plastic film such as polyester or triacetyl cellulose directly or via an adhesive layer, a resin coating layer, and an acrylic or epoxy-based photocurable resin layer. . 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 optically anisotropic axis and having an optically anisotropic axis 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 such that each optically anisotropic axis is continuously twisted in multiple layers. Like a normal TN liquid crystal cell, it has a twist angle. 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 semi-transmissive reflecting plate. However, it is particularly preferable to provide between the linear polarizing plate and the liquid crystal cell. As the optical compensation element, a twist-aligned liquid crystal cell itself, a liquid crystal film, a laminate of a retardation film, or the like can be used. As the twist-aligned liquid crystal cell, a liquid crystal cell in which a layer of a liquid crystal material 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. Can be mentioned as an example.
Further, 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. Such a liquid crystal film,
After a liquid crystal material exhibiting nematic liquid crystal properties is twisted and nematically aligned, the alignment structure can be obtained by a method of fixing by, for example, photo-crosslinking or thermal cross-linking, or a method of fixing as a glass state by cooling. it can.

The liquid crystal material is not particularly limited as long as it has a nematic liquid crystal property, and various low-molecular liquid crystal substances, high-molecular liquid crystal substances, or a mixture thereof can be used as the material. The molecular shape of the liquid crystal material is
Regardless of whether it is rod-shaped or disk-shaped, for example, discotic liquid crystals exhibiting discotic nematic liquid crystal properties 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 if the alignment structure can be fixed, the composition of the material or There is no limitation on the composition ratio or the like. For example, a mixture of a single or plural kinds of low-molecular and / or high-molecular liquid crystal substances and a single or plural kinds of low-molecular and / or high-molecular non-liquid crystal substances and various additives is used as a liquid crystal material. Can also.

The low-molecular liquid crystal material includes Schiff base, biphenyl, terphenyl, ester, thioester, stilbene, tolan, azoxy, azo, phenylcyclohexane, pyrimidine, and cyclohexylcyclohexane. And low molecular weight liquid crystal compounds having a trimesic acid-based, triphenylene-based, torquecene-based, phthalocyanine-based, and porphyrin-based molecular skeleton, or a mixture of these compounds.

As the high-molecular liquid crystal substance, various main-chain high-molecular liquid crystal substances, side-chain high-molecular liquid crystal substances, or mixtures thereof can be used. As the main chain type polymer liquid crystal material, polyester, polyamide, polycarbonate, polyimide, polyurethane, polybenzimidazole, polybenzoxazole, polybenthiazole, polyazomethine, polyesteramide, polyester carbonate And polyesterimide-based polymer liquid crystals, and mixtures thereof. Among these, semi-aromatic polyester-based polymer liquid crystals in which mesogenic groups that impart liquid crystallinity and bent chains of polymethylene, polyethylene oxide, polysiloxane, etc. are alternately bonded, and wholly aromatic polyester-based polymers without bent chains Liquid crystals are desirable in the present invention.

The side-chain type high-molecular liquid crystal material includes a linear or cyclic backbone such as polyacrylate, polymethacrylate, polyvinyl, polysiloxane, polyether, polymalonate, and polyester. Or a mixture thereof, in which a mesogen group is bonded as a side chain to a substance having the following formula: Among these, a side-chain type polymer liquid crystal in which a mesogen group providing liquid crystallinity is bonded to a skeletal chain via a spacer consisting of a bent chain, or the polymer liquid crystal having a molecular structure having a mesogen in both the main chain and the side chain. 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 non-liquid crystal materials having at least one kind of chiral structural unit in order to induce twisted nematic alignment. . Examples of the chiral structural unit include optically active 2-methyl-1,4-butanediol, 2,4-pentanediol, 1,2-propanediol, and 2-chloro-1,4.
-Butanediol, 2-fluoro-1,4-butanediol, 2-bromo-1,4-butanediol, 2-ethyl-1,4-butanediol, 2-propyl-1,4-
Butanediol, 3-methylhexanediol, 3-methyladipic acid, naproxen derivative, camphoric acid,
Units derived from binaphthol, menthol, or a cholesteryl group-containing structural unit or a derivative thereof (for example, a derivative such as a diacetoxy compound) can be used. The above-mentioned chiral structural unit may be any of R-form and S-form, or may be a mixture of R-form and S-form. Note that these structural units are merely examples, and the present invention is not limited thereto.

In preparing a liquid crystal film, when the alignment structure formed in the liquid crystal state is fixed by thermal crosslinking or photocrosslinking, a functional group or site capable of reacting by heat or photocrosslinking reaction or the like in the liquid crystal material. It is desirable to mix various liquid crystal substances having the same. Examples of the functional group capable of undergoing a cross-linking reaction include an epoxy group such as an acryl group, a methacryl group, a vinyl group, a vinyl ether group, an allyl group, an allyloxy group and a glycidyl group, an isocyanate group, an isothiocyanate group, an azo group, a diazo group, and an azide. Groups, a hydroxyl group, a carboxyl group, a lower ester group and the like, and an acryl group and a methacryl group are particularly desirable. Examples of the site capable of undergoing a crosslinking reaction include sites having a molecular structure such as maleimide, maleic anhydride, cinnamic acid and cinnamate, alkene, diene, arene, alkyne, azo, azoxy, disulfide, and polysulfide. . These cross-linking groups and cross-linking reaction sites may be included in the various liquid crystal substances constituting the liquid crystal material itself, or a non-liquid crystal material having a cross-linking group or site may be separately added to the liquid crystal material.

Another example which can be used as an optical compensator constituting the present invention is a retardation film having a pseudo twist structure by continuously twisting the optically anisotropic axis similarly to the liquid crystal film. Can be mentioned. Retardation films are generally polycarbonate-based, cellulose-based, polyarylate-based, polysulfone-based, polyacryl-based, polyethersulfone-based,
It can be formed by uniaxially or biaxially stretching a transparent plastic film represented by a norbornene-based or cyclic olefin-based resin. An optical compensator 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 compensating element constituting the present invention, it is preferable that the dispersion of the birefringence varies depending on the wavelength, similarly to the birefringence Δn of the liquid crystal material used in the liquid crystal cell. Birefringence of the optical compensation element at wavelengths λ = 450 nm and λ = 590 nm (hereinafter “Δn ₂ (450)”, “Δn ₂ (590)”)
It expresses. ) Is defined as birefringence wavelength dispersion α ₂ , α ₂ = Δn ₂ (450) / Δn ₂ (590). alpha ₂ but is identical if the liquid crystal material is identical, is that the same be a different liquid crystal material. In the present invention, it can be said that α ₂ = 1.11 to 1.40 is preferable in combination with the above-described liquid crystal cell. That is, in the transflective liquid crystal display device of the present invention, the birefringence wavelength dispersion alpha ₂ of the birefringence wavelength dispersion alpha ₁ and the optical compensation element of the liquid crystal material layer, α ₁ = 1.01~1.35 α ₂ = By setting the ratio in the range of 1.11 to 1.40, it becomes possible to provide a transflective liquid crystal display element having achromatic and high-contrast reflective display characteristics. In particular, by setting the birefringence wavelength dispersion value so as to satisfy α ₁ <α ₂ , it can be said that reflection display characteristics with more achromatic color and high contrast can be more remarkably achieved.

Further, the optical compensating element constituting the present invention provides a product of the birefringence Δn ₂ and the thickness d ₂ of the optically anisotropic body (Δn ₂ ···
d ₂ ) may have a temperature compensation effect that varies with temperature. By using such an optical compensating element, it is possible to provide a reflective liquid crystal display element in which color development hardly fluctuates even when the ambient temperature changes, and which can perform good monochrome display. In this case, the temperature change of Δn ₂ · d ₂ is caused by the birefringence Δn ₁ of the liquid crystal material layer in the liquid crystal cell used for driving.
It is desirable that the change (Δn ₁ · d ₁ ) of the product of the thickness d ₁ and the thickness d ₁ be substantially equal to the change with temperature. In the transflective liquid crystal display element of the present invention, the twist angle θ ₂ of the slow axis of the optical compensation element from the side of the linear polarizer to the side of the semi-transmissive reflector (circular polarizer) is −2.
It is preferably in the range of 20 degrees or more and -155 degrees or less. The product (Δn ₂ · d ₂ ) of the refractive index anisotropy Δn ₂ of the optical compensator and the thickness d ₂ of the optical compensator is 550.
It is preferably in the range of not less than nm and not more than 850 nm.
As described above, by setting θ ₂ and θ ₁ to values in specific ranges, and Δn ₁ · d ₁ and Δn ₂ · d ₂ to values in specific ranges, excellent contrast characteristics are realized. can do.

Further, in the transflective liquid crystal display device of the present invention, in addition to restricting α ₁ , α ₂ , θ ₁ , θ ₂ , Δn ₁ · d ₁ and Δn ₂ · d ₂ to a specific range, , The angle θ ₃ from the absorption axis of the linear polarizing plate to the slow axis of the optical compensator on the surface of the linear polarizing plate, and the orientation direction of the liquid crystal material layer from the absorption axis of the linear polarizing plate on the surface of the linear polarizing plate. Angle θ ₄ to
By making adjustments as follows, it is possible to realize less coloration and good contrast. θ ₃ = 0 to + 40 ° or +90 to + 130 ° θ ₄ = 0 to + 40 ° or +90 to + 130 ° Particularly, the angle θ ₄ is set when the optical compensating element is disposed between the linear polarizing plate and the liquid crystal material layer. At +90 to +13
It is more preferable that the angle is in the range of 0 °, or in the range of 0 to + 40 ° when the optical compensation element is disposed between the liquid crystal material layer and the transflective plate.

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 arranged on a transparent substrate on the side of a circularly polarizing plate in a liquid crystal cell, and can be installed in a liquid crystal cell as in the case of the above-mentioned linearly polarizing plate. When the transflective plate is installed in the liquid crystal cell, the transflective plate may also have a function as an electrode of the liquid crystal cell. The transflective plate is not particularly limited, and includes metals such as aluminum, silver, gold, chromium, platinum, and copper and alloys containing them, oxides such as magnesium oxide, dielectric multilayer films, and combinations thereof. Examples can be given. As the transflective plate, one that partially transmits light by performing processing such as controlling the thickness of the reflective layer or providing holes or slits is used. Further, the shape of the semi-transmissive reflection plate may be flat or curved, and may be such that a surface shape such as an uneven shape is processed to have a diffuse reflection property.

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. The liquid crystal material layer is disposed on the side opposite to the side on which the linear polarizing plate is provided. As the ellipticity of the circularly polarizing plate at a wavelength λ = 550 nm, 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, and as the ellipticity becomes smaller than 1, Thus, it is possible to achieve a transmissive display that emphasizes brightness. 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 composed of the above-described linearly polarizing plate and the optically anisotropic element is preferable in the present invention. As the linearly polarizing plate used for the circularly polarizing plate, a polarizing film of the same type as the linearly polarizing plate provided on the opposite side of the liquid crystal material layer from the circularly polarizing plate can be used. Furthermore, a reflective polarizing film can be used as the linear polarizing plate constituting the circular polarizing plate.

The optically anisotropic element is an element that produces a phase difference of approximately (2n + 1) / 4 wavelengths (here, n = 0, 1, 2,...) In the visible light range, that is, linearly polarized light is converted into substantially circularly polarized light. Alternatively, any element having an action of converting into elliptically polarized light close to substantially circularly polarized light can be used without any limitation. Above all, as an element for generating a phase difference of approximately (2n + 1) / 4 wavelength in the visible light range, n = 0 or 1 is particularly preferable.
In this case, an element that generates a phase difference of approximately one-quarter wavelength or approximately three-quarters wavelength is desirable for realizing good transmissive display.

As an optically anisotropic element for generating a phase difference of approximately (2n + 1) / 4 wavelengths (here, n = 0, 1, 2,...) In the visible light region, optically uniaxial or biaxial is used. Examples thereof include an optically anisotropic element having a refractive index structure, an optically anisotropic element having a twisted structure, and a combination of a plurality thereof. As the optically anisotropic element having an optically uniaxial or biaxial refractive index structure, polycarbonate-based, cellulose-based, polyarylate-based, polysulfone-based, polyacryl-based, polyethersulfone-based, norbornene-based, Examples thereof include a retardation film formed by uniaxially or biaxially stretching a transparent plastic film represented by a cyclic olefin-based resin and the like, and a retardation film formed by nematically aligning a liquid crystal material. 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. A wide-band quarter-wave plate manufactured by combining a half-wave plate is exemplified.

Examples of the optically anisotropic element having a twisted structure include a twisted liquid crystal cell itself, a liquid crystal film, or a laminate of a retardation film. As the twisted 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. As these optically anisotropic elements, those having a temperature compensation effect can be preferably used similarly to the above-mentioned optical compensation element.

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 optical anisotropic element having such a twist structure,
In particular, birefringence Δn ₃ and thickness d _{3 at a} wavelength λ = 550 nm
(Nm) is 140 nm or more and 400 (Δn ₃ · d ₃ )
nm or less, and the torsion angle θ ₆ is 30 as an absolute value.
It is desirable that the angle is not less than 85 degrees and not more than 85 degrees from the viewpoint of circular polarization characteristics. Furthermore, it can be said that an optically anisotropic element satisfying any of the following conditions is particularly desirable because it exhibits favorable circular polarization characteristics in combination with the above-described linear polarizing plate. (1) Δn ₃ · d ₃ is 155 nm or more and 175 nm or less, and the torsion angle θ ₆ is 40 degrees or more and 50 degrees or less as an absolute value. (2) Δn ₃ · d ₃ is 176 nm or more and 216 nm or less, and the torsion angle θ ₆ is 58 degrees or more and 70 degrees or less as an absolute value. (3) Δn ₃ · d ₃ is 230 nm or more and 270 nm or less, and the torsion angle θ ₆ is 70 degrees or more and 80 degrees or less 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 transmission 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 of a specular reflection type, it is preferable to provide a light diffusing layer for reflection display.
The light diffusion layer is not particularly limited as long as it has a property of diffusing parallel light isotropically or anisotropically. For example, a material having two or more types of regions and having a difference in refractive index between the regions, or a material having surface irregularities can be used. Examples of the above-mentioned two or more regions having a refractive index difference between the regions include a matrix in which particles having a different refractive index from the matrix are dispersed. The light diffusion layer itself may have adhesiveness.

Although the thickness of the light diffusion layer is not particularly limited, it is generally preferable that the thickness is 10 μm or more and 500 μm or less. The total light transmittance of the light diffusion layer is 50%.
It is preferably at least 70%, particularly preferably at least 70%. Further, the haze value of the light diffusion layer is usually 1
It is 0 to 95%, preferably 40 to 90%, and more preferably 60 to 90%. The reflection type liquid crystal display element of the present invention is a liquid crystal cell, a linear polarizing plate,
The optical compensator, the transflector, and the circularly polarizing plate are provided as essential components, and a light diffusion layer is provided as necessary. 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 multicolor or full-color display with high color purity can be obtained. Also, if necessary, backlight,
Front light, light control film, light guide plate, prism sheet, anti-reflection layer, anti-glare treatment layer, adhesive layer, adhesive layer,
It is also possible to provide a hard coat layer or the like.

[0036]

According to the transflective liquid crystal display element of the present invention, bright display can be obtained for both reflective display and transmissive display, high contrast and good color display can be realized. Significantly higher display quality can be obtained as compared with the element.

[0037]

EXAMPLES 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 creating an element with the counterclockwise direction + and the clockwise direction − from the linear polarizing plate side to the transflective plate side. However, the same result can be obtained by conducting an experiment in the same manner with the clockwise direction + and the counterclockwise direction − from the linear polarizing plate side to the semi-transmissive reflecting plate side. Further, the retardation value (= Δn · d) in the present embodiment is a value at a wavelength λ = 550 nm unless otherwise specified.

[0038]Example 1 STN type transflective liquid crystal display element schematically shown in FIG.
A child was made. As shown in FIG. 1, the liquid crystal cell 3
The pair of transparent substrates 3D facing each other and the side opposite to the display surface (FIG. 1)
Transflective plate 3 provided on the surface of a transparent substrate (below).
C, the electrodes 3B provided on the inner surfaces thereof,
Alignment film 3 printed and formed on them and subjected to alignment treatment
F. Alignment film 3F and print coating around substrate
Liquid crystal material in the space defined by the sealing agent 3E
The liquid crystal material layer 3A is formed. Liquid crystal material
Film 3F using ZLI-2293 (manufactured by Merck)
The liquid crystal material layer 3A is formed by adjusting the alignment processing direction of
Orientation in a predetermined direction, θ ₁= Twisted to +250 degrees
I let you. Further, the birefringence of the liquid crystal material in the liquid crystal cell 3 △ n₁When
Thickness d of liquid crystal material layer 3A₁Product △ n₁・ D₁Is about 800
nm. Birefringence wavelength dispersion α of ZLI-2293
₁(Α₁= Δn₁(450) / Δn₁(590)) is 1.1
It was 0.

A linear polarizing plate 1 (SR1862AP, manufactured by Sumitomo Chemical Co., Ltd.) is disposed on the display surface side (upper side of the figure) of the liquid crystal cell 3, and has a twisted structure between the linear polarizing plate 1 and the liquid crystal cell 3. The optical compensation element 2 was arranged. △ of the optical compensation element 2
n ₂ · d ₂ was approximately 670 nm, the twist angle was θ ₂ = -190 degrees, and the birefringence wavelength dispersion α _{2 was} 1.15. At this time,
The angle θ ₃ = + 20 degrees from the absorption axis of the linear polarizing plate 1 to the alignment axis on the surface of the optical compensation element 2 on the side of the linear polarizing plate, and the angle between the absorption axis of the linear polarizing plate 1 and the linear polarizing plate side of the liquid crystal material layer 3A. The angle θ ₄ to the orientation direction on the surface was set to +105 degrees. In addition, a linear polarizing plate 4B (SR manufactured by Sumitomo Chemical Co., Ltd.)
1862AP) and an optically anisotropic element 4A having a twisted structure
Is arranged behind the liquid crystal cell when viewed from the display side. Optically anisotropic element 4A having a twisted structure
Δn ₂ · d ₂ is approximately 190 nm, and the torsion angle is θ ₆ = −65.
Degree. At this time, the angle θ from the absorption axis of the linear polarizing plate 1 to the alignment axis on the liquid crystal cell side surface of the optically anisotropic element 4A.
₅ = + 35 degrees, the linear polarizing plate 4
The angle of B to the absorption axis was θ ₇ = + 60 degrees. In this axial arrangement, the ellipticity of the portion of the circularly polarizing plate 4 at a wavelength λ = 550 nm was measured by an ellipsometer (DVA-36VWLD manufactured by Mizojiri Optical Industrial Co., Ltd.) and found to be 0.94. Further, a light diffusion layer 5 is provided between the optical compensator 2 and the liquid crystal cell 3 as a light diffusion layer, in which a substantially spherical fine particle having a different refractive index from the matrix is dispersed in a matrix made of an acrylic adhesive. Having a total light transmittance of 90% and a haze value of 80%, and a normal transparent pressure-sensitive adhesive layer between the linear polarizer 1 and the optical compensator 2 and between the liquid crystal cell 3 and the circular polarizer 4. Was placed.

FIG. 2 shows the relationship between the angles θ _{1 to} θ ₇ of the constituent members of the STN transflective liquid crystal display element. In addition,
FIG. 2 shows the axial arrangement of each component when the transflective liquid crystal display element is viewed from the display side. In FIG. 2, the orientation direction 31 of the liquid crystal material layer 3A on the surface on the side of the linear polarizing plate 1 and the orientation direction 32 on the surface of the side of the circularly polarizing plate 4 form an angle θ ₁ . The direction 21 of the alignment axis on the surface of the optical compensator 2 on the side of the linear polarizing plate 1 and the direction 22 of the alignment axis on the surface on the side of the liquid crystal cell form an angle θ ₂ . The direction 41 of the alignment axis on the surface of the optically anisotropic element 4A on the side of the linear polarizing plate 1 and the direction 42 of the alignment axis on the side of the linear polarizing plate 4B form an angle θ ₆ .
The absorption axis 11 of the linear polarizing plate 1 and the direction 21 of the alignment axis on the surface of the optical compensating element 2 on the side of the linear polarizing plate 1 form an angle θ _3, and the absorption axis 11 of the linear polarizing plate 1 The orientation direction 31 on the surface of the material layer 3A on the side of the linear polarizing plate 1 forms an angle θ ₄ . The orientation direction 41 of the optically anisotropic element 4A in the circularly polarizing plate 4 on the side surface of the liquid crystal cell is:
The absorption axis 11 of the linear polarizing plate 1 forms an angle θ ₅ with the absorption axis 11 of the linear polarizing plate 4B, and the absorption axis 43 of the linear polarizing plate 4B forms an angle θ ₇ with the absorption axis 11 of the linear polarizing plate 1.

A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and a backlight is arranged so that the backlight is not lit ( When the optical characteristics in the reflection mode and the lighting mode (transmission mode) were examined, bright and high-contrast display was possible 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 a liquid crystal cell, good multi-color or full-color display can be performed.

Example 2 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 880 nm, Δn ₂ · d ₂ of the optical compensator ₂ is approximately 740 nm, and the birefringence wavelength dispersion α ₂ =
1.13 and Δn ₃ · d ₃ of the optically anisotropic element 4A is approximately 16
5 nm, θ ₁ = + 240 degrees, θ ₂ = −180 degrees, θ ₃
= + 15 degrees, θ ₄ = + 110 degrees, θ ₅ = + 30 degrees, θ ₆ =
A liquid crystal display device similar to that of Example 1 was manufactured except that −45 degrees and θ ₇ = + 60 degrees. With this axis arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VW manufactured by Mizojiri Optical Industrial Co., Ltd.).
LD) was 0.93. A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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 a liquid crystal cell, good multi-color or full-color display can be performed.

Example 3 Δn ₁ · d ₁ of the liquid crystal cell 3 was approximately 840 nm, Δn ₂ · d ₂ of the optical compensation element ₂ was approximately 710 nm, and the birefringence wavelength dispersion α ₂ =
1.13, and Δn ₃ · d ₃ of the optically anisotropic element 4A is approximately 25.
0 nm, θ ₁ = + 240 degrees, θ ₂ = −180 degrees, θ ₃
= + 15 degrees, θ ₄ = + 110 degrees, θ ₅ = + 30 degrees, θ ₆ =
A liquid crystal display device similar to that of Example 1 was manufactured except that −75 degrees and θ ₇ = + 60 degrees. With this axis arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VW manufactured by Mizojiri Optical Industrial Co., Ltd.).
LD) was 0.93. A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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 a liquid crystal cell, good multi-color or full-color display can be performed.

Example 4 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 850 nm, Δn ₂ · d ₂ of the optical compensation element ₂ is approximately 690 nm, and the birefringence wavelength dispersion α ₂ =
1.15, and Δn ₃ · d ₃ of the optically anisotropic element 4A is approximately 37.
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = −20 degrees, θ ₆ =
A liquid crystal display device similar to that of Example 1 was manufactured except that −45 degrees and θ ₇ = + 50 degrees. With this axis arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VW manufactured by Mizojiri Optical Industrial Co., Ltd.).
LD) was 0.90. A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Example 5 Δn ₁ · d ₁ of the liquid crystal cell 3 was approximately 850 nm, Δn ₂ · d ₂ of the optical compensation element ₂ was approximately 690 nm, and the birefringence wavelength dispersion α ₂ =
５n ₃ · d ₃ of the optically anisotropic element 4A is approximately 28
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = −5 degrees, θ ₆ = −
A liquid crystal display device similar to that of Example 1 was manufactured except that the angle was set to 60 degrees and θ ₇ = + 40 degrees. In this axial arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VWL manufactured by Mizojiri Optical Industrial Co., Ltd.).
It was 0.81 when measured in D). A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Embodiment 6 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 850 nm, Δn ₂ · d ₂ of the optical compensation element ₂ is approximately 690 nm, and the birefringence wavelength dispersion α ₂ =
５n ₃ · d ₃ of the optically anisotropic element 4A is approximately 34.
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = + 5 degrees, θ ₆ = −
A liquid crystal display device similar to that of Example 1 was manufactured except that the angle was set to 60 degrees and θ ₇ = + 65 degrees. In this axial arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VWL manufactured by Mizojiri Optical Industrial Co., Ltd.).
It was 0.94 when measured in D). A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Embodiment 7 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 850 nm, Δn ₂ · d ₂ of the optical compensation element ₂ is approximately 690 nm, and the birefringence wavelength dispersion α ₂ =
５n ₃ · d ₃ of the optically anisotropic element 4A is approximately 19
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = + 50 degrees, θ ₆ =
A liquid crystal display device similar to that of Example 1 was manufactured except that −75 degrees and θ ₇ = + 70 degrees. With this axis arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VW manufactured by Mizojiri Optical Industrial Co., Ltd.).
LD) was 0.86. A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Embodiment 8 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 850 nm, Δn ₂ · d ₂ of the optical compensation element ₂ is approximately 690 nm, and the birefringence wavelength dispersion α ₂ =
1.15, and Δn ₃ · d ₃ of the optically anisotropic element 4A is approximately 32.
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = 0 degrees, θ ₆ = -7
A liquid crystal display device similar to that of Example 1 was produced except that the angle was set to 5 degrees and θ ₇ = + 40 degrees. With this axis arrangement, the circularly polarizing plate 4
The ellipticity of the portion at a wavelength λ = 550 nm was determined by an ellipsometer (DVA-36VWL manufactured by Mizojiri Optical Industrial Co., Ltd.).
It was 0.84 when measured in D). A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Example 9 Δn ₁ · d ₁ of the liquid crystal cell 3 was approximately 850 nm, Δn ₂ · d ₂ of the optical compensator ₂ was approximately 690 nm, and the birefringence wavelength dispersion α ₂ =
Δn ₃ · d ₃ of the optically anisotropic element 4A is approximately 22
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = 15 degrees, θ ₆ = −
A liquid crystal display device similar to that of Example 1 was produced except that the angle was set to 60 degrees and θ ₇ = + 50 degrees. In this axial arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VWL manufactured by Mizojiri Optical Industrial Co., Ltd.).
It was 0.78 when measured in D). A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Embodiment 10 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 950 nm, Δn ₂ · d ₂ of the optical compensation element 2 is approximately 810 nm, and the birefringence wavelength dispersion α ₂ =
５n ₃ · d ₃ of the optically anisotropic element 4A is approximately 19
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 20 degrees, θ ₄ = + 100 degrees, θ ₅ = 20 degrees, θ ₆ = −
A liquid crystal display device similar to that of Example 1 was manufactured except that 65 ° and θ ₇ = + 55 °. In this axial arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VWL manufactured by Mizojiri Optical Industrial Co., Ltd.).
It was 0.69 when measured in D). A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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, good multi-color or full-color display can be performed.

Embodiment 11 Δn ₁ · d ₁ of the liquid crystal cell 3 is approximately 800 nm, Δn ₂ · d ₂ of the optical compensation element ₂ is approximately 650 nm, and the birefringence wavelength dispersion α ₂ =
５n ₃ · d ₃ of the optically anisotropic element 4A is approximately 19
0 nm, θ ₁ = + 250 degrees, θ ₂ = −190 degrees, θ ₃
= + 15 degrees, θ ₄ = + 100 degrees, θ ₅ = −10 degrees, θ ₆ =
A liquid crystal display device similar to that of Example 1 was produced except that +65 degrees and θ ₇ = + 55 degrees. With this axis arrangement, the ellipticity of the circularly polarizing plate 4 at a wavelength λ = 550 nm is determined by using an ellipsometer (DVA-36VW manufactured by Mizojiri Optical Industrial Co., Ltd.).
LD) was 0.90. A driving voltage is applied to the above-mentioned liquid crystal display element from a driving circuit (not shown) to the electrode 3B (driving at 1/100 duty, optimal bias), and when the backlight is not lit (reflection mode) and lit (transmission mode). When the optical characteristics of (2) were examined, bright and high-contrast displays were obtained 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 a liquid crystal cell, good multi-color or full-color display can be performed.

Embodiment 12 The birefringence wavelength dispersion α ₁ = 1.
21 using ZLI-5049 (manufactured by Merck).
n ₁ · d ₁ is approximately 790 nm, and Δn ₂ · d _{2 of the} optical compensation element ₂
Is approximately 650 nm and the birefringence wavelength dispersion α ₂ = 1.24,
Δn ₃ · d ₃ of the optically anisotropic element 4A is set to approximately 190 nm, and θ
₁ = + 250 °, theta ₂ = -190 °, theta ₃ = + 15 °, theta ₄
= + 100 degrees, θ ₅ = 20 degrees, θ ₆ = −65 degrees, θ ₇ = +
A liquid crystal display device similar to that of Example 1 was produced except that the angle was 55 degrees. With this axis arrangement, the wavelength λ of the circularly polarizing plate 4 portion =
The ellipticity at 550 nm was determined using an ellipsometer (Ltd.)
It was 0.69 when measured with DVA-36VWLD manufactured by Mizojiri Optical Industrial Co., Ltd. A drive voltage is applied to the above liquid crystal display element from the drive circuit (not shown) to the electrode 3B (1/1).
When the optical characteristics at the time of driving at 100 duty and the optimum bias), when the backlight is not lit (reflection mode) and when the backlight is lit (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, good multi-color or full-color display can be performed.

Embodiment 13 As the liquid crystal material of the liquid crystal cell 3, the birefringence wavelength dispersion α ₁ = 1.
21 using ZLI-5049 (manufactured by Merck).
n ₁ · d ₁ is approximately 790 nm, and Δn ₂ · d _{2 of the} optical compensation element ₂
Is approximately 650 nm, and the birefringence wavelength dispersion α ₂ = 1.21,
Δn ₃ · d ₃ of the optically anisotropic element 4A is set to approximately 190 nm, and θ
₁ = + 250 °, theta ₂ = -190 °, theta ₃ = + 15 °, theta ₄
= + 100 degrees, θ ₅ = 20 degrees, θ ₆ = −65 degrees, θ ₇ = +
A liquid crystal display device similar to that of Example 1 was produced except that the angle was 55 degrees. With this axis arrangement, the wavelength λ of the circularly polarizing plate 4 portion =
The ellipticity at 550 nm was determined using an ellipsometer (Ltd.)
It was 0.69 when measured with DVA-36VWLD manufactured by Mizojiri Optical Industrial Co., Ltd. A drive voltage is applied to the above liquid crystal display element from the drive circuit (not shown) to the electrode 3B (1/1).
When the optical characteristics at the time of driving at 100 duty and the optimum bias), when the backlight is not lit (reflection mode) and when the backlight is lit (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, good multi-color or full-color display can be performed.

Comparative Example 1 Birefringence wavelength dispersion α ₁ = 1.
21 using ZLI-5049 (manufactured by Merck).
n ₁ · d ₁ is approximately 790 nm, and Δn ₂ · d _{2 of the} optical compensation element ₂
Is approximately 650 nm, and the birefringence wavelength dispersion α ₂ = 1.10.
Δn ₃ · d ₃ of the optically anisotropic element 4A is set to approximately 190 nm, and θ
₁ = + 250 °, theta ₂ = -190 °, theta ₃ = + 15 °, theta ₄
= + 100 degrees, θ ₅ = 20 degrees, θ ₆ = −65 degrees, θ ₇ = +
A liquid crystal display device similar to that of Example 1 was produced except that the angle was 55 degrees. With this axis arrangement, the wavelength λ of the circularly polarizing plate 4 portion =
The ellipticity at 550 nm was determined using an ellipsometer (Ltd.)
It was 0.69 when measured with DVA-36VWLD manufactured by Mizojiri Optical Industrial Co., Ltd. A drive voltage is applied to the above liquid crystal display element from the drive circuit (not shown) to the electrode 3B (1/1).
When the optical characteristics when the backlight was not lit (reflection mode) and when the backlight was lit (transmission mode) were examined, the black color when the voltage was turned off was blue and the contrast was low. Display characteristics could not be obtained.

[Brief description of the drawings]

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

FIG. 2 shows an absorption axis of a linear polarizing plate, a liquid crystal cell, an optical compensator, and a liquid crystal display device of Examples 1 to 13 and Comparative Example 1.
It is a top view explaining axis angle relations of a circularly polarizing plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Linear polarizing plate 2 Optical compensation element 3 Liquid crystal cell 3A Liquid crystal material layer 3B Electrode 3C Transflective reflector 3D Transparent substrate 3E Sealant 3F Alignment film 4 Circular polarizing plate 4A Optical anisotropic element 4B Linear polarizing plate 5 Light diffusion layer 11 Observation Absorption axis of the linear polarizing plate 1 on the side of the user 21 orientation axis of the optical compensating element on the side of the linear polarizing plate 1 22 orientation axis of the optical compensating element on the side of the liquid crystal cell 31 31 orientation of the liquid crystal layer 3A on the surface of the linear polarizing plate 1 side Direction 32 Alignment direction of liquid crystal layer 3A on the surface on the side of circular polarizer 4 41 Alignment direction of optical anisotropic element 4A on the side of liquid crystal cell 3 42 Alignment direction of optical anisotropic element 4A on the side of linear polarizing plate 4B 43 Linear Absorption axis of polarizing plate 4B

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Uesaka 8 Chidoricho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Central Research Laboratory, Nisseki Mitsubishi Co., Ltd. (72) Inventor Takehiro Toyooka 8, Chidoricho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Address Mitsui Nishiishi Co., Ltd. Central Research Laboratory F-term (reference) 2H049 BA02 BA03 BA06 BA42 BB03 BB61 BC22 2H091 FA08X FA08Z FA11X FA11Z FA14Z FA21Z FA23Z FA41Z HA07 HA10 LA17

Claims (6)

[Claims] 1. A liquid crystal cell comprising a pair of transparent substrates provided with electrodes and a layer of liquid crystal material inserted therein, a linear polarizer, an optical compensator having a twisted structure, a transflector, and a circular polarizer. A transflective liquid crystal display device in which a voltage value of two or more is selected and a driving voltage is applied to the liquid crystal material layer, wherein 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 reflector is disposed between the liquid crystal material layer and the circularly polarizing plate; If the ratio of the birefringence Δn at wavelengths λ = 450 nm and λ = 590 nm is defined as birefringence wavelength dispersion αα = Δn (450) / Δn (590), the birefringence of the liquid crystal material layer double the wavelength dispersion alpha ₁ and the optical compensation element Transflective liquid crystal display device diffracted wavelength dispersion alpha _2, characterized in that in the range of _{α 1 = 1.01~1.35 α 2 = 1.11~1.40} . 2. The twist angle θ ₁ of liquid crystal substance molecules from the side of the linear polarizer to the side of the transflective plate in the liquid crystal substance layer is +
The twist angle θ ₂ of the slow axis of the optical compensating element from the side of the linear polarizer to the side of the semi-transmissive reflector is in the range of not less than −220 degrees and not more than +270 degrees. The product of the birefringence Δn ₁ and the thickness d _{1 at} the wavelength λ = 550 nm of the liquid crystal material layer (Δn ₁ · d ₁ ) is 700 nm.
The product (Δn ₂ · d ₂ ) of the birefringence Δn _{2 at} the wavelength λ = 550 nm of the optical compensation element and the thickness d ₂ of the optical compensation element is 550 nm.
2. The transflective liquid crystal display device according to claim 1, wherein the range is at least 850 nm. 3. The optically anisotropic element according to claim 1, wherein the circularly polarizing plate comprises at least a linearly polarizing plate and an optically anisotropic element, and the optically anisotropic element has a twisted structure.
3. The transflective liquid crystal display device according to item 1. 4. A birefringence Δn ₃ and a thickness d ₃ (n) at a wavelength λ = 550 nm of an optically anisotropic element constituting the circularly polarizing plate.
product of _{m) (Δn 3 · d 3} ) is, 400 nm or more 140nm
And the twist angle θ ₆ of the slow axis of the optically anisotropic element from the linear polarizing plate side to the circular polarizing plate side is 3 as an absolute value.
4. The transflective liquid crystal display device according to claim 1, wherein the angle is in a range of 0 to 85 degrees. 5. A birefringence Δn ₃ and a thickness d _{3 at} a wavelength λ = 550 nm of an optically anisotropic element constituting the circular linear polarizing plate.
(Nm) of the product (Δn ₃ · d ₃₎ and twist angle from linear polarizing plate side of the slow axis of the optical anisotropic element into circularly polarizing plate side θ
₆ is (1) 155 nm or more and 175 nm or less and 40 degrees or more and 50 degrees or less as an absolute value;
16 nm or less and an absolute value of 58 degrees or more and 70 degrees or less,
(3) The transflective liquid crystal display element according to any one of claims 1, 2, 3, and 4, wherein one of the conditions of 230 to 270 nm and an absolute value of 70 to 80 degrees is satisfied. 6. 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.