WO2004031846A1 - Semitransmissive reflective liquid crystal display element - Google Patents

Abstract

A semitransmissive reflective liquid crystal display element providing a bright display with high contrast in transmission mode, capable of being desiged thin and having a low view angle dependence. The semitransmissive reflective liquid crystal display element comprises a first substrate having a transparent electrode, a second substrate having a semitransmissive reflective electrode, a nematic liquid crystal layer sandwiched between the first and second substrates, a first optically anisotropic element and a sheet of polarizing plate placed on the first substrate, and a second optically anisotropic element and a sheet of polarizing plate placed on the second substrate, wherein the first optically anisotropic element comprises a phase difference film satisfying specified requirements and the second optically anisotropic element is formed of a liquid crystal polymer substance exhibiting optically positive uniaxiality.

Description

 Transflective liquid crystal display device

[Technical field]

 The present invention has a combination of a reflective light type and a transmissive type used in OA equipment such as a word processor and a personal computer, portable information equipment such as an electronic organizer and a mobile phone, or a camera-integrated VTR equipped with a liquid crystal monitor. Liquid crystal display device.

[Background technology]

 In recent years, liquid crystal display devices can make full use of their thin and lightweight features.

Expectations for market expansion as device displays are growing. Since portable electronic devices are 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 consumes a large amount of power and does not need to be used, or does not need to be used at all times, can be reduced in power consumption, thinner, and lighter. Has received particular attention.

As a reflection type liquid crystal display device, a two-type reflection type liquid crystal display device in which a liquid crystal cell is sandwiched between a pair of polarization plates and a reflection plate is further disposed outside is widely used for monochrome display. More recently, reflective LCDs with a single polarizer, in which the liquid crystal layer is sandwiched between a polarizer and a reflector, have been put to practical use because they are in principle brighter and easier to color than two-polarizers. . Polarizing plate In a single-panel reflective liquid crystal display device, a 1Z 4 wavelength plate is used as a retardation plate between the polarizing plate and the liquid crystal cell to have a substantially circular polarizing plate function. By making the thickness of the liquid crystal layer in the inside approximately 1/4 wavelength, a normally white reflective liquid crystal display device has been realized (for example, see Japanese Patent Publication No. Publication No. 98/4320, refer to pamphlets etc.). The quarter-wave plate used for the phase difference plate has a phase difference of approximately 1/4 wavelength in birefringent light of 550 nm monochromatic light in order to give good circular polarization characteristics. It has been proposed to use at least two or more retardation films consisting of a wave plate and a half-wave plate whose phase difference between birefringent light of 550 nm monochromatic light is approximately 1 Z 2 wavelengths. Yes (example For example, see JP-A-10-68816. ).

 However, since these reflective liquid crystal display elements usually perform display using external light, they have a drawback that the display becomes difficult to see when used in a dark environment. As a technology to solve this problem, in a reflective liquid crystal display device with a single polarizing plate, a semi-transmissive reflector that has the property of transmitting part of the incident light is used instead of a reflector, and a backlight is used. There has been proposed a transflective liquid crystal display device having the following (see, for example, Japanese Patent Application Laid-Open No. 10-246846). In this case, it 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 a lit pack light in a dark environment.

 In this transflective liquid crystal display device with one polarizing plate, in the transmissive mode, substantially circularly polarized light needs to be incident on the liquid crystal cell through the transflective layer. It is necessary to arrange a circularly polarizing plate comprising a typical stretched polymer film and a polarizing plate between the transflective layer and the pack light. However, in the transmissive mode liquid crystal display device, the viewing angle problem that the display color changes or the display contrast decreases when viewed obliquely due to the refractive index anisotropy of the liquid crystal molecules is essential. With a circular polarizer using a stretched polymer film, it is essentially difficult to increase the viewing angle.

 In recent years, there has been an increasing demand for thinner and lighter portable information terminal devices, and there has been an increasing demand for thinner and lighter components used in displays of portable information terminal devices. However, in the case of stretched polymer films, there is a limit in thinning due to manufacturing problems.

 An object of the present invention is to provide a transflective liquid crystal display element which has a bright display in a transmissive mode, has high contrast, can be designed to have a small thickness, and has a small viewing angle dependence. .

[Disclosure of the Invention]

According to a first aspect of the present invention, there is provided a first substrate having a transparent electrode, a second substrate having a transflective electrode in which a region having a reflective function and a region having a transmissive function are formed, A nematic liquid crystal layer sandwiched between the first substrate and the second substrate; A first optical anisotropic element provided on a surface opposite to a surface in contact with the liquid crystal layer, and one polarizing plate; and a first optical anisotropic element provided on a surface of the second substrate opposite to the surface in contact with the liquid crystal layer. A transflective liquid crystal display device comprising a second optically anisotropic element and one polarizing plate provided, wherein the first optically anisotropic element is a retardation film comprising one polymer oriented film. And the retardation values at wavelengths (λ) of 450 nm, 550 nm and 650 nm are Re (450), Re (550) and Re (650), respectively. ), A retardation film satisfying the following formulas (I) and (),

 R e (4 5 0) <R e (5 5 0) <R e (6 5 0) (I)

 0.2 ≤R e (λ) / λ≤ 0.3 (Π)

 The second optically anisotropic element is substantially formed of at least one optically positive uniaxial liquid crystal polymer material, and the liquid crystal polymer material forms a nematic hybrid alignment formed in a liquid crystal state. The present invention relates to a transflective liquid crystal display device comprising a fixed liquid crystal film (Α).

 In a second aspect of the present invention, in the transflective liquid crystal display element described above, the second optically anisotropic element is substantially more than at least one optically positive uniaxial liquid crystalline polymer material. Characterized in that the liquid crystalline polymer material is composed of a liquid crystal film (Α) in which the nematic hybrid alignment formed in a liquid crystal state is fixed, and at least one stretched polymer film. The present invention relates to the transflective liquid crystal display device described above.

 In a third aspect of the present invention, in the transflective liquid crystal display element described above, the second optically anisotropic element is substantially more than at least one optically positive uniaxial liquid crystalline polymer material. A liquid crystal film (Α) formed in a liquid crystal state, wherein the liquid crystal polymer substance is formed in a liquid crystal state, and at least one liquid crystal polymer substance having optically positive uniaxiality A transflective liquid crystal display element as described above, wherein the liquid crystal high molecular substance is formed substantially in a liquid crystal state, and the liquid crystal film is formed in a liquid crystal state and has a fixed nematic alignment. About.

A fourth aspect of the present invention is that the liquid crystal film (Α) force S, the liquid crystal material is nematic hybrid aligned in a liquid crystal state, and is cooled from that state by nematic alignment. The present invention relates to the transflective liquid crystal display element described above, which is a liquid crystal film having a hybrid alignment fixed to glass.

 A fifth aspect of the present invention is the liquid crystal film, wherein the liquid crystal film (A) is a liquid crystal film in which a liquid crystal material is nematic hybrid aligned in a liquid crystal state, and a nematic hybrid orientation is fixed by a crosslinking reaction. And a transflective liquid crystal display device.

 In a sixth aspect of the present invention, the liquid crystal layer thickness of the region having the reflection function is different from the liquid crystal layer thickness of the region having the transmission function. The transflective liquid crystal display element described above, which is thinner than the above.

 A seventh aspect of the present invention relates to the above-mentioned transflective liquid crystal display device, characterized in that an ECB (Electrically Controlled Birefringence) system is used.

 An eighth aspect of the present invention relates to the above-mentioned transflective liquid crystal display device, characterized by using a TN (Twisted Nematic) system.

 A ninth aspect of the present invention relates to the transflective liquid crystal display device described above, wherein a H ANG (Hybrid Aligned Nematic) system is used. Hereinafter, the present invention will be described in detail.

 The transflective liquid crystal display device of the present invention includes a polarizing plate, a first optically anisotropic device, a liquid crystal cell, a second optically anisotropic device, a polarizing plate, and a backlight, as viewed from the observer side. In addition, members such as a light diffusion layer, a light control film, a light guide plate, and a prism sheet can be further added as necessary. In this type of liquid crystal display device, both the reflection mode and the transmission mode can be used by installing a pack light at the rear.

 Next, the liquid crystal cell used in the present invention will be described.

 The liquid crystal cell used in the present invention includes: a first substrate having a transparent electrode; a second substrate having a transflective electrode in which a region having a reflective function and a region having a transmissive function are formed; It comprises a first substrate and a nematic liquid crystal layer sandwiched between the second substrates.

The liquid crystal cell has a half in which a region having a reflection function and a region having a transmission function are formed. Although the area including the transmissive / reflective layer is provided, the area having the reflective function is a reflective display section for performing the reflective display, and the area having the transmissive function is the transmissive display section for performing the transmissive display.

 It is preferable that the thickness of the liquid crystal layer of the reflective display portion of the liquid crystal cell is smaller than that of the transmissive display portion. The reason will be described below.

 First, the transmissive display in the transmissive display unit when the liquid crystal layer thickness is set to a layer thickness suitable for reflective display will be described. When a liquid crystal layer suitable for reflective display is set, the amount of change in the polarization state due to a change in the alignment due to an external field such as an electric field of the liquid crystal layer depends on the amount of light incident through the liquid crystal layer from the observer side. The light is reflected by the reflective layer and is emitted again to the viewer side through the liquid crystal layer, so that a sufficient contrast ratio can be obtained by reciprocating through the liquid crystal layer. However, in this setting, the amount of change in the polarization state of light passing through the liquid crystal layer is insufficient in the transmissive display section. For this reason, even if a polarizing plate used only for transmissive display is installed on the back side of the liquid crystal cell as viewed from the observer, in addition to the polarizing plate installed on the observer side of the liquid crystal cell used for reflective display, the transmissive display section Sufficient display cannot be obtained. In other words, when the alignment condition of the liquid crystal layer is set to the alignment condition of the liquid crystal layer suitable for the reflective display unit, the transmissive display unit lacks brightness or transmits the dark display even if the brightness is sufficient. The ratio does not decrease, and a sufficient contrast ratio for display cannot be obtained.

 More specifically, when performing reflective display, the voltage applied to the liquid crystal layer is adjusted so that a phase difference of approximately 1/4 wavelength is imparted to light passing through the liquid crystal layer only once. The alignment state of the liquid crystal inside is controlled. As described above, when performing transmissive display by performing voltage modulation that provides a liquid crystal layer thickness suitable for reflective display, that is, phase modulation of 1 Z 4 wavelengths, the transmissive display section can sufficiently reduce the transmittance when dark display is performed. In this case, when the transmissive display section performs bright display, light of about half the luminous intensity is absorbed by the polarizing plate on the light emission side, and sufficient bright display cannot be obtained. Also, if optical elements such as a polarizing plate and a phase difference compensator are arranged to increase the brightness when the transmissive display unit is bright, the brightness when the transmissive display unit is 喑 display will be the brightness at the time of bright display. Of about 1 Z 2, resulting in an insufficient display contrast ratio.

Conversely, in order to set the thickness of the liquid crystal layer to a condition suitable for transmissive display, it is necessary to apply voltage modulation to the liquid crystal layer so that light transmitted through the liquid crystal layer is given a phase difference of 1 Z 2 wavelengths. is there. Therefore, both reflected light and transmitted light can be displayed with high resolution and excellent visibility. Therefore, it is necessary to make the liquid crystal layer thickness of the reflective display section smaller than the liquid crystal layer thickness of the transmissive display section. Ideally, the thickness of the liquid crystal layer in the reflective display section is preferably about 12 times the thickness of the liquid crystal layer in the transmissive display section.

 As the liquid crystal cell system, TN (Twisted Nematic) system, STN (Super Twisted Nematic) system, ECB (Electrically Controlled Birefringence) system, IPS (In-Plane Switching) system, VA (Vertical Alignment) system, OCB (Optically Compensated Birefringence) method, HAN (Hybrid Aligned Nematic) method, ASM (Axially Symmetric Aligned Microcell) method, no-tone tone gray scale method, domain division method, or use ferroelectric liquid crystal, anti-ferroelectric liquid crystal Various methods, such as a display method described above, may be used.

 In the case of the TN mode, the twist direction of the liquid crystal layer may be left-handed or right-handed. The twist angle is preferably 90 degrees or less, and more preferably 70 degrees or less. If the angle is larger than 90 degrees, unnecessary coloring may occur on the liquid crystal display device.

 There is no particular limitation on the driving method of the liquid crystal cell. A passive matrix method used for STN-LCDs and the like, and an active matrix using an active electrode such as a TFT (Thin Film Transistor) electrode or a TFD (Thin Film Diode) electrode. And any driving method such as a plasma addressing method.

 The transparent substrate constituting the liquid crystal cell is not particularly limited as long as the material exhibiting liquid crystallinity constituting the liquid crystal layer is oriented in a specific orientation. Specifically, a transparent substrate in which the substrate itself has a property of aligning liquid crystal, and a transparent substrate in which an alignment film or the like having a property of aligning liquid crystal is provided thereon, although the substrate itself lacks alignment ability. Either can be used. In addition, known electrodes such as ITO can be used for the electrodes of the liquid crystal cell. The electrode can be usually provided on the surface of the transparent substrate in contact with the liquid crystal layer. When a substrate having an alignment film is used, it can be provided between the substrate and the alignment film.

The material exhibiting liquid crystallinity for forming the liquid crystal layer is not particularly limited, and examples thereof include ordinary various low-molecular liquid crystal substances, high-molecular liquid crystal substances, and mixtures thereof that can form various liquid crystal cells. In addition, a dye, a chiral agent, a non-liquid crystalline substance, and the like can be added to these as long as the liquid crystallinity is not impaired. The region having a reflective function included in the semi-transmissive reflective electrode (hereinafter, also referred to as a reflective layer) is not particularly limited, and metals such as aluminum, silver, gold, chromium, and platinum, alloys containing them, and oxides An oxide such as magnesium, a dielectric multilayer film, a liquid crystal exhibiting selective reflection, a combination thereof, or the like can be given. These reflective layers may be flat or curved. In addition, the reflective layer is formed by processing the surface shape such as an uneven shape so as to have a diffuse reflection property, and also serving as an electrode on the electrode substrate on the side opposite to the viewer side of the liquid crystal cell. It may be a combination.

 The polarizing plate used in the present invention is not particularly limited as long as the object of the present invention can be achieved, and a normal polarizing plate used in a liquid crystal display device can be appropriately used. More specifically, iodine and Z or 2 or 3 are added to a hydrophilic high molecular film composed of a partially saponified product of PVA-based ethylene monovinyl acetate copolymer such as polyvinyl alcohol (PVA) or partially acetalized PVA. A polarizing film made of a polarizing film stretched by adsorbing a chromatic dye or a polyene-oriented film such as a dehydrated PVA product or a dehydrochlorinated polyvinyl chloride product can be used. Further, a reflective polarizing film can also be used.

 The polarizing plate may be used alone as the polarizing film, or may be 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, moisture resistance, heat resistance, etc. good. Examples of the transparent protective layer include those obtained by laminating a transparent plastic film such as polyester or triacetylcellulose directly or via an adhesive layer, a transparent resin coating layer, and a photocurable resin layer such as an acryl-based or epoxy-based resin. It is possible. When these transparent protective layers are coated on both sides of the polarizing film, different protective layers may be provided on both sides.

 The first optically anisotropic element used in the present invention has a retardation value at a wavelength of 450 nm, a wavelength of 550 nm, and a retardation value of 65 nm at Re (450) and Re, respectively. (550) and Re (650), a retardation film composed of one polymer oriented film satisfying the following formulas (I) and (Π).

 R e (4 5 0) <R e (5 5 0) C R e (6 5 0) (I)

0.2 ≤R e (λ) / λ≤ 0.3 (Π) A retardation film that satisfies the above formula (I), that is, one polymer oriented film having a smaller retardation value as the wavelength becomes shorter, is determined by a polymer oriented film that satisfies the following condition (A) or (B). Obtainable.

 (A) (1) Forming a monomer unit that forms a polymer compound having a positive refractive index anisotropy (hereinafter referred to as a first monomer unit) and a polymer compound having a negative refractive index anisotropy (2) a high molecular compound based on the first monomer unit, R e (4 (50) / R e (550) is smaller than R e (450) / R e (550) of the polymer compound based on the second monomer unit, and (3) An oriented film having a positive refractive index anisotropy.

 (B) (1) Forming a monomer unit forming a polymer compound having a positive refractive index anisotropy (hereinafter referred to as a first monomer unit) and a polymer compound having a negative refractive index anisotropy (2) a high molecular compound based on the first monomer unit, R e (4 (50) / R e (550) is larger than R e (450) / R e (550) of the polymer compound based on the second monomer unit, and (3) An oriented film having negative refractive index anisotropy.

 Examples of an embodiment that satisfies the above conditions (A) and (B) include those that satisfy the following conditions (C) and (D).

 (C) (1) A blend polymer comprising a polymer compound having a positive refractive index anisotropy and a polymer compound having a negative refractive index anisotropy; A film comprising a copolymer comprising a monomer unit forming a polymer compound having the same and a monomer unit forming a polymer compound having a negative refractive index anisotropy,

(2) R e (450) / R e (550) of the polymer compound having the positive refractive index anisotropy is represented by R e ( (3) An oriented film having a refractive index anisotropy smaller than 450 / R e (550).

(D) (1) A blend polymer consisting of a polymer compound having a positive refractive index anisotropy and a polymer compound having a negative refractive index anisotropy and having a Z or a positive refractive index anisotropy. Monomer unit forming a high molecular compound and a polymer compound having a negative refractive index anisotropy A film comprising a copolymer comprising a monomer unit forming a product,

(2) R e (450) / R e (550) of the polymer having the positive refractive index anisotropy is represented by R e ( (3) An oriented film having a refractive index anisotropy greater than 450) / Re (550).

 Here, the polymer compound having a positive or negative refractive index anisotropy refers to a polymer compound which gives an oriented film having a positive or negative refractive index anisotropy.

 In the present invention, the polymer oriented film used for the first optically anisotropic element may be composed of a blend polymer or copolymer as described above. The polymer material constituting the polymer oriented film may be a blend polymer or a copolymer satisfying the above conditions, and is a thermoplastic polymer having excellent heat resistance, good optical performance, and capable of forming a solution. For example, one or more kinds of polymers such as polyarylate, polyester, polycarbonate, polyolefin, polyether, polysulfine, polysulfone, and polyethersulfone can be appropriately selected. However, if the water absorption of the oriented film is not 1% by weight or less, there is a problem in practical use as a retardation film. Therefore, the film material has a water absorption of 1% by weight or less, preferably 0.5% by weight or less. It is important to choose to meet the requirements.

In the case of a blend polymer, since it is necessary to be optically transparent, it is preferable that the compatible blend or the refractive index of each polymer compound is substantially equal. Specific combinations of the blend polymers include, for example, polymethyl methacrylate as a polymer having negative optical anisotropy, and polyvinylidene fluoride and polyethylene oxalate as polymer having positive optical anisotropy. Or a combination of bilidene-fluoride-do-trifluoroethylene copolymer, polyphenylene oxide as a polymer compound having a positive optical anisotropy, and polystyrene as a polymer compound having a negative optical anisotropy Combination of styrene-laurate ilmaleimide copolymer, styrene-cyclohexinolemaleimide copolymer, or styrene-phenylenoleimide copolymer, styrene-maleic anhydride having negative optical anisotropy A polycarbonate having a positive optical anisotropy with the copolymer, Acrylonitrile-butadiene copolymer having a positive optical anisotropy and an optical anisotropic Preferable examples include, but are not limited to, a tarilonitrile styrene copolymer. In particular, from the viewpoint of transparency, a combination of polystyrene and a polyphenylene oxide such as poly (2,6-dimethyl-11,4-phenylene oxide) is preferable. In the case of such a combination, the ratio of the polystyrene preferably accounts for 67% by weight or more and 75% by weight or less of the whole.

 Examples of the copolymer include a butadiene-styrene copolymer, an ethylene-styrene copolymer, an acrylonitrile-butadiene copolymer, an Atari port-trilubutadiene-styrene copolymer, a polycarbonate copolymer, and a polyester copolymer. Polymers, polyester carbonate copolymers, polyarylate copolymers and the like can be used. In particular, since a segment having a fluorene skeleton can have negative optical anisotropy, a polycarbonate copolymer, a polyester copolymer, a polyester carbonate copolymer, a polyarylate copolymer, etc. having a fluorene skeleton are more preferably used. .

 A polycarbonate copolymer produced by reacting a bisphenol with a phosgene or a carbonate-forming compound such as diphenyl carbonate is excellent in transparency, heat resistance and productivity, and can be particularly preferably used. The polycarbonate copolymer is preferably a copolymer containing a structure having a fluorene skeleton. The component having a fluorene skeleton is preferably contained at 1 to 99 mol%. A preferred material for the oriented film of the present invention is an oriented film of polycarbonate composed of a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): The repeating unit represented by the formula (1) occupies 30 to 90 mol% of the entire polycarbonate, and the repeating unit represented by the formula (2) is a material occupying 70 to 10 mol% of the whole. .

In the above formula (1), 1 ^ to ₁₈ each independently represent a group selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 6 carbon atoms, and X is a group represented by the formula (3) . In addition, in the above formula (2), R ₉ ~! ^ ₆ independently represents a group selected from a hydrogen atom, a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 22 carbon atoms, and Y represents a group selected from the group represented by the formula (4).

In the above formula _{(4), R 17 ~R 19} , 1 21 and 1 ₂₂ are each independently hydrogen atom, a halogen atom and a group selected from a hydrocarbon group having 1 to 22 carbon atoms, R ₂₀ and R ₂₃ Each independently represents a group selected from hydrocarbon groups having 1 to 20 carbon atoms; and represents an aryl group having 6 to 10 carbon atoms.

This material is a polycarbonate copolymer comprising a repeating unit having a fluorene skeleton represented by the above formula (1) and a repeating unit represented by the above formula (2), And a blend polymer of a polycarbonate comprising a repeating unit having a fluorene skeleton represented by the above formula (1) and a polycarbonate comprising a repeating unit represented by the above formula (2). In the case of a copolymer, two or more kinds of the repeating units represented by the above formulas (1) and (2) may be used in combination. In the case of a composition, two or more kinds of the above repeating units may be used in combination.

 In the above formula (1), Ri Rs is independently selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 6 carbon atoms. Examples of the hydrocarbon group having 1 to 6 carbon atoms include an alkyl group such as a methyl group, an ethyl group, an isopropyl group and a cyclohexyl group, and an aryl group such as a phenyl group. Of these, a hydrogen atom and a methyl group are preferred.

In the above formula (2), R _{9 to} R ₁₆ are each independently selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 22 carbon atoms. Examples of such a hydrocarbon group having 1 to 22 carbon atoms include an alkyl group having 1 to 9 carbon atoms such as a methyl group, an ethyl group, an isopropyl group and a cyclohexyl group, a phenyl group, a biphenyl group and a terphenyl group. And other aryl groups. Of these, a hydrogen atom and a methyl group are preferred.

In the above formula _{(4), R 17 ~R 19} , 1 21 and 1 ₂₂ are each independently hydrogen atom, selected from a halogen atom and a hydrocarbon group having 1 to 22 carbon atoms. Such a hydrocarbon group having a carbon number of from 1 to 22 includes an alkyl group having 1 to 9 carbon atoms such as a methyl group, an ethyl group, an isopropyl group and a cyclohexyl group, a phenyl group, a biphenyl group and a terphenyl. And aryl groups such as a group. Of these, a hydrogen atom and a methyl group are preferred. R _2. R ₂₃ is independently selected from a hydrocarbon group having 1 to 20 carbon atoms, and Ar is an aryl group having 6 to 10 carbon atoms such as a phenyl group and a naphthyl group.

The content of the above formula (1), that is, when copolymer composition of the copolymer, if blanking trend composition ratio of the composition is from 30 to 90 mole _^0/0 of the total polycarbonate. Outside of this range, the absolute value of the phase difference does not decrease as the wavelength becomes shorter at the measurement wavelength of 400 to 700 nm. The content of the above formula (1) is preferably 35-8 5 mol _^0/0 of the total polycarbonate, and more preferably 40 to 80 mol%. Here, the above molar ratio is determined by, for example, a nuclear magnetic resonance (NMR) element for the entire polycarbonate pulp constituting the oriented film regardless of the copolymer or the blended polymer. be able to.

 As the polycarbonate in the CCC material, a polycarbonate copolymer and / or a polycarbonate composition composed of a repeating unit represented by the following formula (5) and a repeating unit represented by the following formula (6): (Blended polymer) is preferred.

In the above formula (5), R ₂₄ and R ₂₅ each independently represent a group selected from a hydrogen atom or a methyl group, in the above formula (6), 1 ₂₆ and 1 ₂₇ are each independently a hydrogen atom及Pi methyl And Z represents a group selected from groups represented by the formula (7).

Furthermore, those Oite a copolymer comprising repeating units represented by the following formula (8) to (1 2), the proportion of the repeating unit (1 2) 40 to 75 mole _^0/0, the following equation (9 ) And (12) a copolymer comprising the repeating unit represented by (12), wherein the proportion of (12) is 30 to 70 mol%, and a copolymer represented by the following formulas (10) and (12): in the copolymer consisting return Shi units, the ratio is also 30 to 70 mol _^0/0 (1 2), a copolymer comprising repeating units represented by the following formula (8) and (1 1) Ore, Te, it is preferable to respectively a proportion from 40 to 75 mole _^0/0 (1 1).

The most preferred material is a copolymer or polymer blend containing bisphanol A (BPA, corresponding to the above formula (8)) and biscresol fluorene (BCF, corresponding to the above formula (12)), or a mixture thereof. , blending ratio of these components the content of BCF 5 5 to 7 5 mole _^0/0, more preferably 5 5-7 0 mole ⁰ /. It is. For these materials, we can get closer to ideal; Z 4 board and 1/2 board.

 The above-mentioned copolymer and Z or the blend polymer can be produced by a known method. As the polycarbonate, a method by polycondensation of a dihydroxy compound and phosgene, a melt polycondensation method and the like are suitably used. In the case of a blend, a compatible blend is preferred, but even if they are not completely compatible, light scattering between the components can be suppressed and transparency can be improved by adjusting the refractive index between the components.

The limiting viscosity of the material polymer compound of the polymer oriented film in the present invention is 0.3 to 0.3. It is preferably 2.0 d 1 Z g. If the viscosity is lower than this, there is a problem that the material becomes brittle and the mechanical strength cannot be maintained.If the viscosity is higher than this, the solution viscosity becomes too high, which causes problems such as generation of die lines in solution film formation, and purification at the end of polymerization is difficult. There is a problem that it becomes.

 The polymer oriented film in the invention is preferably transparent, has a haze value of 3% or less, and a total light transmittance of 85% or more. The glass transition temperature of the polymer oriented film material is preferably 100 ° C. or higher, more preferably 120 ° C. or higher. Further, ultraviolet absorbers such as phenylsalicylic acid, 2-hydroxybenzophenone, and triphenyl phosphate, a bluing agent for changing color, and an antioxidant may be added.

 As the polymer oriented film in the present invention, a film obtained by orienting a film of the above polycarbonate or the like by stretching or the like is used. As a method for producing such a film, a known melt extrusion method, a solution casting method, or the like is used, and a solution casting method is more preferably used from the viewpoint of film thickness unevenness, appearance, and the like. As the solvent in the solution casting method, methylene chloride, dioxolane or the like is preferably used.

In addition, a known stretching method can be used for the stretching method, but it is preferably longitudinal uniaxial stretching. In the film, for the purpose of improving stretchability, known plasticizers such as phthalate esters such as dimethyl phthalate, getyl phthalate and dibutyl phthalate, phosphate esters such as tributyl phosphate, and aliphatic dibasic esters, It may contain a glycerin derivative, a glycol derivative or the like. At the time of stretching, the organic solvent used at the time of film formation described above may be allowed to remain in the film for stretching. The amount of the organic solvent is 1 to 20 mass relative to the polymer solid content. / ₀ is preferred.

 Further, the above-mentioned additives such as plasticizer and liquid crystal can change the wavelength dispersion of retardation of the polymer oriented film, but the amount of addition is preferably 10% by mass or less, more preferably 3% by mass or less based on the polymer solid content. preferable.

 The thickness of the polymer oriented film is not particularly limited, but is preferably from 1 im to 400 m.

In order to reduce the retardation of the polymer oriented film at shorter wavelengths, a specific chemical structure is required. It is an essential condition to have a structure, and it should be noted that the chromatic dispersion of the retardation depends to a large extent on its chemical structure, but it also varies depending on stretching conditions, blending conditions, and the like.

 Since a polymer oriented film can form a favorable quarter-wave plate (LZ 4 plate) having a small wavelength dependence particularly with one oriented film, the following formula (Π) is used. To satisfy.

 0 .2≤R e (λ) / λ≤ 0.3 (Π)

 The second optically anisotropic element used in the present invention is an optically positive uniaxial liquid crystal polymer material, specifically, an optically positive uniaxial liquid crystal polymer compound or a small amount thereof. And a liquid crystal polymer composition having optically positive uniaxiality containing at least one liquid crystal polymer compound, wherein the liquid crystal polymer compound or the liquid crystal polymer composition is formed in a liquid crystal state. An element having at least a liquid crystal film (Α) having a fixed nematic hybrid alignment structure having an average tilt angle of 5 ° to 35 °, and having a phase difference of about a quarter wavelength in the visible light region.

 Here, the nematic hybrid alignment refers to an alignment mode in which the liquid crystal molecules are in a nematic alignment, and the angle between the director of the liquid crystal molecules and the film plane is different between the upper surface and the lower surface of the film. Therefore, since the angle formed by the director and the film plane is different between the vicinity of the upper surface interface and the vicinity of the lower surface interface, the angle continuously changes between the upper surface and the lower surface of the film. It can be said that. In a film in which the nematic hybrid alignment state is fixed, directors of liquid crystal molecules are oriented at different angles everywhere in the film thickness direction. Thus, the film no longer has an optical axis when viewed as a film structure.

Further, the average tilt angle in the present invention means the average value of the angle between the director of the liquid crystal molecule and the film plane in the thickness direction of the liquid crystal film. In the liquid crystal film used in the present invention, the angle formed between the director and the film plane near one interface of the film is usually 20 ° to 90 °, preferably 30 ° to 70 ° as an absolute value. At the opposite side of the surface, the angle is usually 0 ° to 20 °, preferably 0 ° to 10 ° as an absolute value, and its average tilt is The angle is usually between 5 ° and 45 ° in absolute value, preferably between 7 ° and 40 °, more preferably between 10 ° and 38 °, most preferably between 15 ° and 35 °. If the average tilt angle is out of the above range, the contrast may be lowered, which is not desirable. The average tilt angle can be obtained by applying the crystal rotation method. The liquid crystal film (A) constituting the second optically anisotropic element used in the present invention is substantially formed of a liquid crystalline polymer material having optically positive uniaxiality. There is no particular limitation on the method of producing the substance as long as the substance has a fixed nematic hybrid alignment state formed in a liquid crystal state. For example, a low-molecular liquid crystal is formed in a nematic hybrid orientation in a liquid crystal state, and then a liquid crystal film obtained by immobilization by photo-crosslinking or thermal cross-linking, or a polymer liquid crystal is formed in a nematic hybrid orientation in a liquid-crystal state, and then cooled. Thus, a liquid crystal film obtained by fixing the orientation can be used. The liquid crystal film in the present invention does not matter whether the film itself exhibits liquid crystallinity, but means a film obtained by forming a liquid crystal material such as a low-molecular liquid crystal or a high-molecular liquid crystal into a film. The film thickness of the liquid crystal film (A) for exhibiting a more favorable viewing angle improving effect on the transflective liquid crystal display element depends on the type of the target liquid crystal display element and various optical parameters. Although it cannot be said unconditionally because it depends, it is usually 0.2 μm to 10 ^ m, preferably 0.3 μπ! To 5 μm, particularly preferably 0.5 m to 2 im. When the film thickness is less than 0.2 μπι, a sufficient compensation effect may not be obtained. If the film thickness exceeds 10 m, the display may be unnecessarily colored.

 Next, the upper and lower sides of the optically anisotropic element made of the liquid crystal film (A), the tilt direction of the optically anisotropic element, and the pretilt direction of the liquid crystal cell layer are defined below with reference to FIGS.

First, in FIGS. 1 and 2, the liquid crystal molecule director and the film near the film interface of the liquid crystal film (A) constituting the optically anisotropic element are positioned above and below the optically anisotropic element composed of the liquid crystal film (A). If the angle between the director of the liquid crystal molecules and the plane of the film forms an angle of 20 to 90 degrees on the acute angle side with respect to the angle between the plane and the plane, it is defined as the b-plane. Make an angle of 0 to 20 degrees on the acute angle side The surface that is facing is the C surface.

 When the c-plane is viewed from the b-plane of the optically anisotropic element through the liquid crystal film layer, the angle formed by the liquid crystal molecular director and the component projected onto the c-plane of the director becomes an acute angle and is parallel to the projected component. Is defined as the tilt direction of the optically anisotropic element.

 Next, in FIG. 3, at the cell interface of the liquid crystal cell layer, the driving low-molecular liquid crystal is not parallel to the cell interface but is inclined at an angle, and this angle is generally called a pretilt angle. The direction in which the angle between the director of the molecule and the component projected onto the interface of the director is an acute angle, and the direction parallel to the projected component of the director is defined as the pretilt direction of the liquid crystal cell layer.

 Further, the second optically anisotropic element can be used in combination with another polymer stretched film or a liquid crystal film (B) in which the nematic orientation is fixed. As a polymer stretched film, a material exhibiting uniaxial or biaxial properties, for example, polycarbonate (PC), polymethacrylate (PMMA), polyvinyl alcohol (PVA), manufactured by Nippon Synthetic Rubber Co., Ltd. A stretched film such as ARTON (trade name) film can be used. Also in this case, in view of the problem of cost increase, the combination of one liquid crystal film and one stretched polymer film is practically preferable.

The liquid crystal film (B) may be formed of any liquid crystal as long as the nematic alignment state is fixed. For example, a liquid crystal film obtained by forming a low-molecular liquid crystal in a nematic orientation in a liquid crystal state and then immobilizing it by photocrosslinking or thermal crosslinking, or a polymer liquid crystal formed in a nematic orientation in a liquid crystal state and then cooled. A liquid crystal film obtained by fixing the orientation can be used. The liquid crystal film (B) referred to in the present invention does not ask whether the film itself exhibits liquid crystallinity as in the case of the liquid crystal film (A), but refers to a liquid crystal substance such as a low molecular liquid crystal or a high molecular liquid crystal. Means obtained by forming a film. Further, as the liquid crystal film included in the second optically anisotropic element, a liquid crystal film alone can be used, and a transparent plastic film can be provided as a support substrate and used. When used as a liquid crystal film alone, a transparent material such as polyester or triacetyl cellulose used for producing the polarizing plate may be used. It can be manufactured by laminating a liquid crystal film on a plastic film and then integrating it with a polarizing plate.

 The retardation value (product of birefringence Δn and film thickness d) of the second optically anisotropic element of the present invention will be described.

 The apparent in-plane retardation value when viewed from the normal direction of the liquid crystal film (A) is the refractive index in the direction parallel to the director (hereafter referred to as ne) in a nematic hybrid oriented film. The refractive index in the vertical direction (hereinafter referred to as no) is different, and when the value obtained by subtracting no from ne is the apparent birefringence, the apparent retardation value is the apparent birefringence. The apparent retardation value can be easily obtained by a polarization optical measurement such as ellipsometry.

 The case where the second optically anisotropic element is composed of only the liquid crystal film (A) in which the nematic hybrid alignment is fixed, and the case where the liquid crystal film (A) and the polymer stretched film or the nematic alignment are fixed. The explanation will be made separately for the case where it is combined with the liquid crystal film (B).

 When the liquid crystal film (A) is composed of only the nematic hybrid oriented liquid crystal film (A), the apparent retardation value of the liquid crystal film (A) is usually 70 nm to 180 nm for a monochromatic light of 550 nm. Good circular polarization characteristics can be obtained by setting the range to preferably 90 nm to 160 nm, particularly preferably 120 nm to 150 nm. If the apparent retardation value is less than 70 nm or greater than 180 nm, unnecessary coloration may occur on the liquid crystal display device.

When the liquid crystal film (A) and the polymer stretched film or the liquid crystal film (B) are combined, as described in JP-A-10-0668816, birefringence with 550 nm monochromatic light is used. The 1Z4 wavelength plate whose light phase difference is approximately 1Z4 wavelength and the 1Z2 wavelength plate whose phase difference of birefringent light of 550 nm monochromatic light is approximately 1Z2 wavelength, and their slow axes are Good circular polarization characteristics can be obtained by laminating in a crossed state. 1 The retardation value of a Z4 wave plate is typically 70 ηπ! The range is from 180 nm to 180 nm, preferably from 90 nm to 160 nm, and particularly preferably from 120 nm to 150 nm. The retardation value of a half-wave plate is usually 1 80 ηπ! ~ 320 nm, good It is preferably in the range of 200 nm to 300 nm, particularly preferably in the range of 220 nm to 280 nm. If the retardation range of the 1/4 wavelength plate and the 1/2 wavelength plate deviates from the above range, unnecessary coloring may occur on the liquid crystal display device.

 The angle between the slow axis of the 1/4 wavelength plate and the slow axis of the 12 wavelength plate is usually 40 to 90 degrees, preferably 50 to 80 degrees, particularly preferably 5 degrees on the acute angle side. The range is 5 degrees to 75 degrees.

 The liquid crystal film (A) in which the nematic hybrid alignment is fixed may be used for a 1/4 wavelength plate or a 1Z 2 wavelength plate.

 When using a liquid crystal film (A) for the 1/4 wavelength plate, use a polymer stretched film or liquid crystal film (B) for the 1/2 wavelength plate, and use a liquid crystal film (A) for the 1/4 wavelength plate. )), A stretched polymer film or liquid crystal film (B) may be used for the 1Z4 wavelength plate.

 The case where only one liquid crystal film (A) is used for a transflective liquid crystal display device as the second optical anisotropic device will be described. The liquid crystal film (A) is preferably disposed between the second substrate of the liquid crystal cell and the polarizing plate. Here, the conditions for disposing the liquid crystal film (A) will be described with reference to FIG. ■

 In the liquid crystal cell 15 in FIG. 6, a straight line overlapping in the pretilt direction of the upper substrate and a straight line overlapping in the pretilt direction of the lower substrate are assumed. These two straight lines are projected on the same plane, and the two angles on the acute side of the four angles formed around the point where the straight lines intersect become straight symmetrical angles. pull. This straight line is defined as a bisector in the present invention. When a straight line overlapping in the pretilt direction of the upper substrate and a straight line overlapping in the pretilt direction of the lower substrate overlap (that is, when two straight lines are parallel), the overlapping straight line is referred to in the present invention. It becomes a bisector.

The angle formed by the bisector and the linear component based on the tilt direction of the liquid crystal film (A) is usually 0 to 30 degrees, preferably 0 to 20 degrees, and more preferably an absolute value. Is desirably arranged so as to be 0 to 10 degrees, most preferably approximately 0 degrees. If the angle between the two is greater than 30 degrees, sufficient viewing angle compensation may not be obtained. Next, the case where a liquid crystal film (A) and a polymer stretched film or a liquid crystal film (B) are combined as a second optically anisotropic element and used as a transflective liquid crystal display element will be described. I do.

 It is preferable that the arrangement of the liquid crystal film (A) is the same as the above-described arrangement in which only one film is used. That is, it is preferable that the tilt direction of the liquid crystalline polymer in the liquid crystal film substantially coincides with the direction of the bisector. The angle between the tilt direction and the pretilt direction is preferably in the range of 0 to 30 degrees, more preferably in the range of 0 to 20 degrees, and particularly preferably in the range of 0 to 10 degrees.

 In the transflective liquid crystal display device of the present invention, the light diffusion layer, the pack light, the light control film, the light guide plate, and the prism sheet are not particularly limited, and known materials can be used.

 In the transflective liquid crystal display element of the present invention, other constituent members can be additionally provided in addition to the constituent members described above. For example, by attaching a color filter to the liquid crystal display element of the present invention, a color liquid crystal display element capable of performing multicolor or full-color display with high color purity can be manufactured.

[Industrial applicability]

 The transflective liquid crystal display element of the present invention is characterized in that the display in the transmission mode is bright, has high contrast, can be designed to be thin, and has little viewing angle dependence.

[Best Mode for Carrying Out the Invention]

 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. Note that the retardation Δnd in this embodiment is a value at a wavelength of 550 nm unless otherwise specified.

(Example 1)

An outline of the transflective liquid crystal display device of the present invention will be described with reference to FIG. 4, and a configuration of the first embodiment will be described with reference to FIG. The second substrate 8 is provided with a reflective electrode 6 formed of a material having a high reflectance such as A1 and a transparent electrode 7 formed of a material having a high transmittance such as ITO. A counter electrode 4 is provided, and a liquid crystal layer 5 made of a liquid crystal material having a positive dielectric anisotropy is sandwiched between the reflection electrode 6 and the transmission electrode 7 and the counter electrode 4. A first optically anisotropic element 2 and a polarizing plate 1 are provided on a surface of the first substrate 3 opposite to the side on which the counter electrode 4 is formed, and a reflection electrode 6 and a transmission electrode 7 of a second substrate 8 are provided. The second optically anisotropic element 9 and the polarizing plate 10 are provided on the side opposite to the surface on which is formed. On the back side of the polarizing plate 10, a backlight 11 is provided.

 A 0.77-μm-thick liquid crystal film 13 with a fixed nematic hybrid orientation with an average tilt angle of 28 degrees in the film thickness direction was fabricated, and the TN type shown below was arranged in the arrangement shown in Fig. 5. Was manufactured.

 The liquid crystal cell 15 used was made of ZLI-1695 (manufactured by Merck) as the liquid crystal material. The liquid crystal layer thickness was 3.5 μπι in the reflective electrode area 6 (reflective display section) and the transmissive electrode area 7 (transmissive In the display section, it was 4.0 μπι. The liquid crystal layer has a pretilt angle of 2 degrees at both substrate interfaces, the twist angle of the liquid crystal cell is 70 degrees with a left-hand twist, and the And of the liquid crystal cell is about 230 nm in the reflective display section and about 262 nm in the transmissive display section. nm.

 A polarizing plate 1 (about 180 μm thick; SQW-862 manufactured by Sumitomo Chemical Co., Ltd.) was placed on the viewer side (upper side of the figure) of the liquid crystal cell 15, and the polarizing plate 1 and the liquid crystal cell 15 were arranged. As the first optically anisotropic element 2, a uniaxially stretched polymer stretched film (product name Pure) manufactured by Teijin Limited that satisfies the formulas (I) and (II), which are the requirements of the present invention. Ace) 2 was placed. The And of the stretched polymer film 2 was approximately 120 nm.

 Further, as the second optically anisotropic element 9, a liquid crystal film 13 and a polymer stretched film 14 made of a uniaxially stretched polycarbonate film are arranged behind the liquid crystal cell 15 as viewed from an observer, and further polarized light is provided on the back side. Plate 10 was placed. The liquid crystal film 13 having the hybrid nematic alignment structure immobilized thereon had an And of 135 nm, and the polymer stretched film 14 had an And of 275 nm.

Absorption axes of polarizing plates 1 and 10, first optical anisotropic body 2 and slow axis of stretched polymer film 14, pretilt direction at both interfaces of liquid crystal cell 15, tilt direction of liquid crystal film 13 Were arranged under the conditions described in FIG. Fig. 7 shows the contrast ratio from all directions when the pack light is turned on (transmission mode) and the contrast ratio of the white display OV and the black display 6 V is the contrast ratio (white display) / (black display). The dagger is shown.

 Fig. 8 shows the viewing angle characteristics of the transmissivity in the left and right directions when 6 gradations are displayed from 0V white display to 6V black display when the backlight is lit (transmission mode).

 Fig. 9 shows the viewing angle characteristics of the transmissivity in the vertical direction when six gradations are displayed from the white display OV to the black display 6V when the pack light is turned on (transmission mode).

 From Figs. 7 to 9, it was found that good viewing angle characteristics were obtained especially in the transmission mode.

(Example 2)

 A liquid crystal film 13 having a thickness of 0.60 μπι with a fixed nematic hybrid orientation having an average tilt angle of 28 degrees in the film thickness direction was prepared, and the EC type shown below was arranged as shown in Fig. 5 Was manufactured.

 The liquid crystal cell 16 used was ZLI-1695 (manufactured by Merck) as the liquid crystal material. The liquid crystal layer thickness was 2.lm in the reflective electrode area 6 (reflective display area) and the transmissive electrode area 7 (transmissive display area). To 4.9 μηι. The pretilt angle at both interfaces of the liquid crystal layer and the substrate was 2 degrees, and the Δnd of the liquid crystal cell was about 138 nm in the reflective display section and about 321 nm in the transmissive display section.

 The polarizing plate 1 (thickness: about 180 μm; SQW-862 manufactured by Sumitomo Chemical Co., Ltd.) is placed on the viewer side (upper side of the figure) of the liquid crystal cell 16, and the polarizing plate 1 is placed between the polarizing plate 1 and the liquid crystal cell 16 In addition, as the first optically anisotropic element 2, a uniaxially stretched polymer stretched film (product name) made of polycarbonate manufactured by Teijin Limited which satisfies the formulas (I) and (II), which are the requirements of the present invention, is used. Pure Ace) 2 placed. The And of the stretched polymer film 2 is approximately 1 15 nm, which is 7 mm.

 Further, Δη d of the liquid crystal film 13 in which the hybrid nematic alignment structure arranged as the second optically anisotropic element 9 was fixed was 105 nm, and Δη d of the stretched polymer film 14 was 270 nm.

Absorption axes of polarizing plates 1 and 10, first optically anisotropic body 2 and stretched polymer film 14 The slow axis, the pretilt direction at both interfaces of the liquid crystal cell 16 and the tilt direction of the liquid crystal film 13 were arranged under the conditions shown in FIG.

 Fig. 11 shows the contrast ratio from all directions as the contrast ratio between the white display OV and black display 6V transmittance (white display) / (black display) when the knock light is turned on (transmission mode). Is shown.

 Fig. 12 shows the viewing angle characteristics of the transmissivity in the left and right directions when 6 gradations are displayed from 0 V white display to 6 V black display when the backlight is lit (transmission mode).

 Figure 13 shows the viewing angle characteristics of the transmittance in the vertical direction when the knock light is turned on (transmission mode) and when 6 gradations are displayed from white display OV to black display 6V.

 Figures 11 to 13 show that the ECB type has excellent viewing angle characteristics, especially in the transmission mode, as does the TN type.

(Comparative Example 1)

 As shown in the layout diagram of FIG. 14, instead of the liquid crystal film 13, polycarbonate 17 (m 11 (1 is approximately 13011111)) was used, the Δnd of the polycarbonate 14 was set to 260 nm, and the liquid crystal cell 1 The same as Example 1 except that the absorption axis of the polarizing plate 10 and the slow axis of the polymer stretched films 14 and 17 arranged on the back side of 5 were arranged under the conditions shown in FIG. A liquid crystal display device was manufactured.

 Fig. 16 shows the contrast ratio from all directions when the backlight ratio (transmissive mode) is 0 V for white display and 6 V for black display as the contrast ratio (white display) / (black display). Is shown.

 Figure 17 shows the viewing angle characteristics of the transmissivity in the left and right directions when displaying 6 gradations from white display OV to black display 6 V when the pack light is on (transmission mode).

 Figure 18 shows the viewing angle characteristics of the transmittance in the vertical direction when six gradations are displayed from white display OV to black display 6 V when the pack light is turned on (transmission mode).

 Example 1 and Comparative Example 1 are compared for viewing angle characteristics.

Comparing the omnidirectional isocontrast curves between FIG. 7 and FIG. 16, it can be seen that a wide viewing angle characteristic is obtained by using the liquid crystal film 13 having a hybrid nematic structure. Comparing the horizontal and vertical gradation characteristics, which are disadvantages in the transmissive mode, between Figs. 8 and 9 and Figs. 17 and 18, the inversion characteristics are improved by using a liquid crystal film with a hybrid nematic structure. It can be seen that it has been greatly improved.

(Comparative Example 2)

 As shown in the layout diagram of FIG. 14, polycarbonate 17 (And is approximately 110 nm) was used instead of liquid crystal film 13, and And of polycarbonate 14 was set to 270 nm. Example 1 except that the absorption axis of the polarizing plate 10 and the slow axis of the stretched polymer films 14 and 17 arranged on the back side of the liquid crystal cell 16 were arranged under the conditions shown in Fig. 19. The same liquid crystal display element as in Example 2 was produced.

 Figure 20 shows the contrast ratio between the white display 0 V and the black display 6 V (white display) / (black display) as the contrast ratio when the pack light is on (transmission mode). It shows the ratio.

 Fig. 21 shows the viewing angle characteristics of the transmissivity in the left and right directions when 6 gradations are displayed from 0 V for white display to 6 V for black display when the backlight is turned on (transmission mode).

 Fig. 22 shows the viewing angle characteristics of the transmittance in the vertical direction when six gradations are displayed from 0 V for white display to 6 V for black display when the backlight is lit (transmission mode).

 Example 2 and Comparative Example 2 are compared for viewing angle characteristics.

 Comparing the omnidirectional isocontrast curves between FIG. 11 and FIG. 20, it can be seen that a wide viewing angle characteristic is obtained by using the liquid crystal film 13 having a hybrid nematic structure.

 Comparing the horizontal and vertical gradation characteristics, which are disadvantages in the transmission mode, between Figs. 12 and 13 and Figs. 21 and 22, the reversal characteristics are improved by using a liquid crystal film with a hybrid nematic structure. It can be seen that it has been greatly improved.

In this embodiment, the experiment was performed without a color filter. However, if a color filter is provided in the liquid crystal cell, it goes without saying that a good multi-color or full-color display can be achieved. [Brief description of drawings]

 FIG. 1 is a conceptual diagram for explaining a tilt angle and a twist angle of a liquid crystal molecule. FIG. 2 is a conceptual diagram of an alignment structure of a liquid crystal film constituting a second optically anisotropic element.

 FIG. 3 is a conceptual diagram illustrating a pretilt direction of a liquid crystal cell.

 FIG. 4 is a cross-sectional view schematically showing a transflective liquid crystal display element of the present invention. FIG. 5 is a cross-sectional view schematically illustrating the transflective liquid crystal display elements of Example 1 and Example 2.

 FIG. 6 is a plan view showing the angle relationship among the absorption axis of the polarizing plate, the pretilt direction of the liquid crystal cell, the slow axis of the polymer stretched film, and the tilt direction of the liquid crystal film in Example 1.

 FIG. 7 is a diagram showing a contrast ratio when the transflective liquid crystal display element in Example 1 is viewed from all directions.

 FIG. 8 is a diagram illustrating viewing angle characteristics of transmissivity in the left and right directions when the transflective liquid crystal display element in Example 1 is displayed in 7 gradations from 0 V to 6 V.

 FIG. 9 is a view showing the viewing angle characteristics of the transmittance in the vertical direction when the transflective liquid crystal display element in Example 1 is displayed in seven gradations from 0 V to 6 V.

 FIG. 10 is a plan view showing an angle relationship among an absorption axis of a polarizing plate, a pretilt direction of a liquid crystal cell, a slow axis of a polymer stretched film, and a tilt direction of a liquid crystal film in Example 2.

 FIG. 11 is a diagram showing a contrast ratio when the transflective liquid crystal display element in Example 2 is viewed from all directions.

 FIG. 12 is a diagram showing viewing angle characteristics of transmissivity in the left and right directions when the transflective liquid crystal display element in Example 2 displays seven gradations from 0 V to 6 V.

 FIG. 13 is a view showing the viewing angle characteristics of the transmittance in the vertical direction when the transflective liquid crystal display element in Example 2 displays seven gradations from 0 V to 6 V.

 FIG. 14 is a cross-sectional view schematically illustrating the transflective liquid crystal display elements of Comparative Examples 1 and 2.

Fig. 15 shows the absorption axis of the polarizing plate, the pretilt direction of the liquid crystal cell, and the FIG. 3 is a plan view showing an angle relationship of a slow axis of the stretched polymer film.

 FIG. 16 is a diagram showing a contrast ratio when the transflective liquid crystal display element in Comparative Example 1 is viewed from all directions.

 FIG. 17 is a diagram showing the viewing angle characteristics of the transmissivity in the left and right directions when the transflective liquid crystal display element in Comparative Example 1 displays seven gradations from 0 V to 6 V.

 FIG. 18 is a diagram showing the viewing angle characteristics of the transmittance in the vertical direction when the transflective liquid crystal display element in Comparative Example 1 displays seven gradations from 0 V to 6 V.

 FIG. 19 is a plan view showing the angle relationship among the absorption axis of the polarizing plate, the pretilt direction of the liquid crystal cell, and the slow axis of the stretched polymer film in Comparative Example 2.

 FIG. 20 is a diagram illustrating a contrast ratio when the transflective liquid crystal display element in Comparative Example 2 is viewed from all directions.

 FIG. 21 is a diagram illustrating viewing angle characteristics of transmissivity in the left and right directions when the transflective liquid crystal display element in Comparative Example 2 displays seven gradations from 0 V to 6 V.

 FIG. 22 is a diagram illustrating viewing angle characteristics of transmittance in the vertical direction when the transflective liquid crystal display element in Comparative Example 2 displays seven gradations from 0 V to 6 V.

Claims

1. a first substrate having a transparent electrode, a second substrate having a transflective electrode in which a region having a reflection function and a region having a transmission function are formed, the first substrate and the second substrate A nematic liquid crystal layer sandwiched between the substrates, a first optically anisotropic element provided on a surface of the first substrate opposite to a surface in contact with the liquid crystal layer, and one polarizing plate. And a second optical contractor provided on a surface of the second substrate opposite to a surface in contact with the liquid crystal layer.

A transflective liquid crystal display device comprising an anisotropic element and one polarizing plate, wherein the first optical anisotropic element is a retardation film composed of one polymer oriented film.

Then, the retardation values at wavelengths (λ) of 450 nm, 550 nm and 650 nm are represented by Re (450), Re (550) and Re (650), respectively. Then, a phase difference film satisfies the following formulas (I) and (Π),

 R e (4 5 0) <R e (5 5 0) R R e (6 5 0) (I)

 0.2≤R e (λ) / l≤ 0.3 (Π)

 The second optically anisotropic element is substantially formed of at least one optically positive uniaxial liquid crystal polymer material, and the liquid crystal polymer material forms a nematic hybrid alignment formed in a liquid crystal state. A transflective liquid crystal display device comprising a fixed liquid crystal film (A).

2. The transflective liquid crystal display element according to claim 1, wherein the second optically anisotropic element is substantially formed of at least one optically positive uniaxial liquid crystal polymer. The liquid crystal polymer material comprising a liquid crystal film (A) in which a nematic hybrid alignment formed in a liquid crystal state is fixed, and at least one stretched polymer film. 13. The transflective liquid crystal display device according to item 13.

3. The transflective liquid crystal display element according to claim 1, wherein the second optically anisotropic element is substantially formed of at least one optically positive uniaxial liquid crystalline polymer. Nematic formed by the liquid crystalline polymer substance in a liquid crystal state A liquid crystal film (A) in which the hybrid alignment is fixed, and at least one optically positive uniaxial liquid crystalline polymer material, which is substantially formed of a liquid crystalline polymer, wherein the liquid crystalline polymer is formed in a liquid crystal state. 2. The transflective liquid crystal display device according to claim 1, comprising a liquid crystal film (B) having a fixed nematic alignment.

4. The liquid crystal film (A) is a liquid crystal film in which a liquid crystal material is aligned in a nematic hybrid orientation in a liquid crystal state, and is cooled from that state to fix the nematic hybrid orientation in glass. Item 4. The transflective liquid crystal display device according to any one of items 1 to 3.

5. The liquid crystal film according to claim 1, wherein the liquid crystal film (A) is a liquid crystal film in which a liquid crystal material is aligned in a nematic hybrid orientation in a liquid crystal state and the nematic hybrid orientation is fixed by a crosslinking reaction. The transflective liquid crystal display device according to any one of the above items.

6. The liquid crystal layer thickness of the region having the reflection function and the liquid crystal layer thickness of the region having the transmission function are different, and the liquid crystal layer thickness of the region having the reflection function is smaller than the liquid crystal layer thickness of the region having the transmission function. The transflective liquid crystal display device according to claim 1.

7. The transflective liquid crystal display device according to claim 1, wherein an ECB (Electrically Controlled Birefringence) system is used.

8. The transflective liquid crystal display device according to claim 1, wherein a TN (Twisted Nematic) system is used.

9. The transflective liquid crystal display device according to claim 1, wherein a H AIN (Hybrid Aligned Nematic) system is used.