JP2000258772A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve problems of the viewing angle such as black color blurring, inversion in the gradation and voids and to obtain a liquid crystal display device having an excellent viewing angle characteristics by forming at least one optical compensation layer between polarizing layers and forming at least one phase type diffraction element layer on the outside of the liquid crystal cell surface. SOLUTION: An optical compensation layer 3A, polarizing layer 2A and phase type diffraction layer 1A are successively formed in this order on the display side (upper side in the figure) out of the both outside faces of a liquid crystal cell 4 through an adhesive layer or cohesive layer 5. On the opposite face of the liquid crystal cell 4, a polarizing layer 2B is formed through an adhesive layer or cohesive layer 5, and further a back liquid system 6 including a prism sheet, diffusion sheet, light guide plate or the like disposed. Thus, by combining the phase type diffraction element layer 1A and the optical compensation layer 3A on the display side, problems caused by the dependence on the viewing angle of the liquid crystal display such as black color blurring, inversion in gradation and voids can be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having excellent viewing angle characteristics.

[0002]

2. Description of the Related Art STN (Super Twisted Nematic) -LC
D (Liquid Crystal Display), TFT (Thin Film Trans
Liquid crystal displays typified by istor) -LCDs are thin, lightweight, low-voltage driven, and have low power consumption. Therefore, they are used as high-performance displays replacing CRTs, such as portable televisions, digital cameras, and video cameras with liquid crystals. Widely used in portable electronic devices, notebook computers, LCD monitors, etc. However, when compared with a cathode ray tube, the liquid crystal display has a major drawback in that the display has a viewing angle dependence. Viewing angle dependency refers to a change in display performance such as contrast, gradation characteristics, and color when the display is viewed obliquely, and generally when viewed obliquely than when the display is viewed from the front. In addition, the display performance deteriorates. This is a problem inherent in a liquid crystal display due to the use of a member such as a liquid crystal or a polarizing plate having a refractive index anisotropy.

[0003] The problem of the viewing angle dependence is particularly large in STN-LCDs, and even if the viewing angle is slightly changed, the display appears to be colored because the brightness is reversed like a negative in a photograph (gradation inversion). Alternatively, phenomena such as the screen becoming completely invisible appear, and the display quality is greatly reduced. This is STN-LC
This is because D is a display method using birefringence. The most widespread TFT-LCDs at present also have a large problem of viewing angle dependence, and the screen becomes black (closed black), looks like a negative photograph (gradation inversion), and the black display floats white (white). Phenomena such as omission) appear. For example, TFT-LCD
In a liquid crystal television, which is one of the important uses of, a slight change in color, a decrease in contrast, and a grayscale inversion due to a viewing angle are uncomfortable. Further, when the size of the liquid crystal display is increased, the same display level cannot be obtained in the central portion and the peripheral portion of the screen.

As a method of solving these viewing angle problems, STN-LCD improves the viewing angle characteristics by optimizing the refractive index in the film thickness direction of a retardation film such as polycarbonate used for color compensation. But the effect is not enough.

A method for improving the viewing angle of a TFT-LCD is as follows.
Halftone grayscale method that divides one pixel and changes the applied voltage to each pixel at a fixed ratio, domain division method that divides one pixel and changes the rising direction of liquid crystal molecules in each pixel, liquid crystal IPS (In-Plane Switching) method that applies a horizontal electric field to the substrate, MVA (Multi-domain Vertical Alignment) liquid crystal method that drives vertically aligned liquid crystal, or OCB (Optically Compensated Birefringence) method that combines a bend alignment cell and an optical compensator Etc. are proposed and developed. However, although these methods have a certain effect, it is necessary to change the alignment film, electrodes, liquid crystal alignment, etc., and it is necessary to establish a manufacturing technology and to newly install a manufacturing facility. Inviting.

On the other hand, there is also known a method of improving the viewing angle characteristics by incorporating an optical compensation film into a conventional TFT-LCD without changing the structure of the TFT-LCD at all.

For example, Japanese Patent Application Laid-Open No. 8-50206 discloses that
There has been proposed a method of using an optical compensation film using discotic liquid crystal molecules as an optical compensation layer of a normally white mode TFT-LCD. In the normally white mode, the liquid crystal molecules at the time of applying a voltage are almost vertically aligned with the electrode substrate, but are near the substrate due to the strong anchoring effect of the substrate. Therefore, the director of the liquid crystal molecules is not uniform in the film thickness direction, but has a hybrid structure that is gradually changed. Based on the idea that the optical compensation film should cancel the refractive index anisotropy of the orientation form in the liquid crystal cell when such a voltage is applied, the discotic liquid crystal is hybrid-aligned, and the alignment is fixed. The viewing angle dependency is improved by arranging a total of two optical compensation layers between the liquid crystal cell and the polarizing plates provided on both outer surfaces of the liquid crystal cell. However, in the method using the optical compensation film, although the hybrid structure in the liquid crystal cell changes depending on the magnitude of the driving voltage, the discotic liquid crystal in the film for compensating for it has a fixed hybrid structure. In addition, it is not clear that the effect is sufficient in all gradations, and it has also become clear that the liquid crystal display tends to be colored yellow when viewed from the left and right directions. Further, in the optical compensation film as exemplified in this example, the arrangement angle between the liquid crystal cell and the film is limited, so that the effect of expanding the viewing angle is limited to only a specific direction in the plane of the liquid crystal display device. However, there is a problem that tone inversion cannot be suppressed.

As another method for improving the viewing angle characteristics, there is an example in which a diffusion sheet is used. For example, a collimating (light collecting) sheet is provided on the backlight side of the liquid crystal cell in order to eliminate the anisotropy of the optical path from the backlight to the liquid crystal cell.
It has been proposed to additionally provide a diffusion sheet on the opposite side of the liquid crystal cell, that is, on the display side. In short, the light emitted from the backlight is aligned in the normal direction of the display surface with a special collimating sheet, and is diffused in all directions with a special diffusion sheet when emitted from the liquid crystal cell.
However, this method is effective for all LCDs, but it is difficult to manufacture sheets uniformly.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device which has improved viewing angle problems such as blackout, grayscale inversion and white spots in a liquid crystal display device, and has excellent viewing angle characteristics. It is in.

[0010]

According to the present invention, at least a liquid crystal cell having a liquid crystal phase formed between two opposing transparent electrode substrates, and a polarizing layer disposed outside both surfaces of the liquid crystal cell are provided. In the liquid crystal display device, there is provided a liquid crystal display device comprising at least one optical compensation layer between the polarizing layers and at least one phase-type diffraction element layer outside the surface of the liquid crystal cell. .

Further, according to the present invention, the optical compensation layer contains a liquid crystal material having optically positive or negative uniaxiality,
The liquid crystal display device is provided, which comprises at least an optically anisotropic element in which the hybrid alignment or the twist hybrid alignment of the liquid crystal material is fixed.

Further, according to the present invention, there is provided the liquid crystal display device, wherein the phase type diffraction element layer is at least composed of a liquid crystalline film.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display device according to the present invention basically comprises a liquid crystal cell having a liquid crystal phase formed between two opposing transparent electrode substrates, a polarizing layer, an optical compensation layer, and a phase type diffraction element layer. Configuration.

The transparent electrode substrate in the liquid crystal cell used in the present invention is not particularly limited, and a known electrode substrate for controlling a material having a liquid crystal property at the time of screen display can be used, and the object of the present invention is achieved. There is no particular limitation as long as it is possible.

The material exhibiting liquid crystallinity is not particularly limited, and examples thereof include ordinary various low-molecular liquid crystal substances, high-molecular liquid crystal substances, and mixtures thereof which can constitute various liquid crystal cells. The liquid crystal cell may include, in addition to the transparent electrode substrate and the material exhibiting liquid crystallinity, various components necessary for forming a liquid crystal cell of various types described below.

The type of the liquid crystal cell is not particularly limited. For example, a TN (Twisted Nematic) type, an STN (Su
per Twisted Nematic), ECB (Electrically Cont)
rolled Birefringence), IPS (In-Plane Switchi)
ng) method, VA (Vertical Alignment) method, OCB (Opti
cally Compensated Birefringence (ASM), ASM (Axial
(Symmetric Aligned Microcell) system, halftone gray scale system, domain division system, or a display system using a ferroelectric liquid crystal or an antiferroelectric liquid crystal. The liquid crystal cell of the above method has two types of display modes, normally black display and normally white display, depending on whether the polarization directions of the two polarizing plates are parallel or orthogonal. It can be used preferably.

There is no particular limitation on the driving method of the liquid crystal cell. A simple matrix method used for STN-LCDs and the like, a TFT (Thin Film Transistor) electrode, an MIM
(MetalInsulator Metal) electrode and TFD (Thin Film D)
Any driving method such as an active matrix method using an active electrode such as an iode) electrode or a plasma addressing method may be used.

The polarizing layer used in the liquid crystal display of the present invention comprises:
Any ordinary polarizing layer or the like disposed outside both surfaces of the liquid crystal cell may be used, and is not particularly limited as long as the object of the present invention can be achieved. The polarizing layer may be disposed on both outer surfaces of the liquid crystal cell and directly in contact with the outer surface of the transparent electrode substrate, but may be transparent through an optical compensation layer, a phase-type diffraction element layer, and other layers described later. It may be arranged separately from the surface of the electrode substrate.

In the liquid crystal display device according to the present invention, at least one polarizing layer is disposed between the polarizing layers disposed outside both surfaces of the liquid crystal cell.
And an optical compensation layer. Specifically, the optical compensation layer can be provided between the liquid crystal cell and one of the polarizing layers sandwiching the liquid crystal cell, and between the liquid crystal cell and both the polarizing layers sandwiching the liquid crystal cell. Can also be provided.

The optical compensation layer is a layer for improving the viewing angle characteristics and the tint of the liquid crystal display device by adjusting the polarization state of light passing through the liquid crystal cell, and is composed of a single optically anisotropic element. It is possible to use a layer formed by laminating two or more optically anisotropic elements of the same type or different types.

The optically anisotropic element is not particularly limited as long as it is light-transmitting and has optical anisotropy. Specifically, (a) a non-liquid crystal film, or (b) And a liquid crystal film.

The (a) non-liquid crystalline film includes stretching, film forming, rolling, drawing, solid extrusion, blow molding,
Films in which the molecular chains of the non-liquid crystalline film material are oriented by a forming operation such as vapor deposition to impart optical anisotropy are exemplified.

Examples of the non-liquid crystalline film material include cellulose polymers such as polycarbonate, polymethyl methacrylate, polyvinyl alcohol, polypropylene, polyarylate, and triacetyl cellulose; polystyrene, polyamide, aramid, polyimide, polysulfone, and polyethersulfone. And polymers such as norbornene-based polymers and polyesters.

As the (a) non-liquid crystal film, a film obtained by stretching the polymer or the like or a film formed therefrom can be preferably used. Specifically, a uniaxial or biaxial film obtained by subjecting the polymer to various stretching operations can be preferably used. When a film is formed by dissolving the polymer once in a solvent to form a polymer solution, the refractive index in the film thickness direction is higher than the refractive index (nx or ny) in the film plane due to the orientation of the polymer when the solvent is dried. In some cases, the film may have a negative C orientation (nx = ny> nz) having a small ratio (nz) or a positive C orientation (nx = ny <nz), and vice versa. Can be. Further, a negative anisotropic film (nx ≧ ny> nz) produced by further stretching such a film such as a uniaxial film or a reverse positive anisotropic film (nx ≦ ny <nz) is also available. It can be used preferably.

As the non-liquid crystal film (a), a film whose optical axis is inclined with respect to the normal direction of the film can be preferably used. For example, a film obtained by vertically or obliquely depositing an inorganic compound such as SiO or tantalum pentoxide, or a vertically or obliquely deposited film produced by depositing or vapor-depositing and polymerizing various organic compounds or organic compounds having a functional group can be preferably used.

As the liquid crystal film (b), there can be mentioned a film in which various liquid crystal materials are oriented or a film in which the orientation is fixed. Here, whether or not the alignment is fixed is not relevant from the viewpoint of optical performance, but a fixed film is practically preferable because the alignment of the liquid crystal material in the optically anisotropic element is hardly disturbed by heat or external force.

As the liquid crystal material, a material capable of exhibiting a liquid crystal phase such as a nematic liquid crystal phase, a smectic liquid crystal phase or a discotic liquid crystal phase can be used, and a liquid crystal containing a liquid crystal material having an optically positive or negative uniaxial property can be used. Materials are particularly preferred.

The liquid crystal material having optically positive uniaxiality is a rod-shaped liquid crystal material such as a nematic liquid crystal material, and has a refractive index in a direction parallel to the director (ne) and a refractive index in a direction perpendicular to the director. A liquid crystal material including a liquid crystal material whose difference from (no) is positive, that is, Δn = ne−no> 0 can be given.

The liquid crystal material having an optically negative uniaxial property is a discotic liquid crystal material such as a discotic liquid crystal material, which is perpendicular to the refractive index (ne) in the direction parallel to the director. A liquid crystal material including a liquid crystal material having a negative difference from the refractive index (no) in the direction, that is, Δn = ne−no <0, can be used.

The mode of orientation of the liquid crystal material in the liquid crystal film (b) is not particularly limited, but includes homogeneous orientation, homeotropic orientation, tilt orientation, twisted orientation, cholesteric orientation, hybrid orientation, twisted hybrid orientation, and the like. No.

Particularly preferable embodiments of the optical compensation layer include a liquid crystal material having an optically positive uniaxial property, and at least a liquid crystal material having at least an optically anisotropic element in which a hybrid orientation is fixed. Including a liquid crystal material showing an optically negative uniaxial property, a liquid crystal material having at least a hybrid alignment of an optically anisotropic element in which the hybrid orientation is fixed, including a liquid crystal material showing an optically positive uniaxial property, A liquid crystal material comprising at least an optically anisotropic element in which the twisted hybrid orientation of the liquid crystal material is fixed, and a liquid crystal material exhibiting optically negative uniaxiality, wherein the twisted hybrid orientation of the liquid crystal material is fixed. At least an optically anisotropic element may be used. Further, an optical compensation layer obtained by adding another optically anisotropic element to these optically anisotropic elements is also preferable. Examples of the other optically anisotropic element include the uniaxial film, the negative C-oriented film, and the negative anisotropic film.

In the above-described optically anisotropic element, the magnitude of the vector of the director of the liquid crystal material having optically positive uniaxiality, such as a nematic liquid crystal material, projected onto the element plane is as follows.
A hybrid orientation changed in the film thickness direction is exhibited.

FIG. 1 schematically shows one example of the hybrid orientation. In the orientation shown in FIG. 1, the direction of the director of the liquid crystal material is along the direction of the regulating force near the interface A to which the orientation regulating force is applied by rubbing or the like, but as the orientation approaches the interface B, the direction of the director increases. The direction is approaching perpendicular to the interface.

The film thickness of the above-mentioned optically anisotropic element is usually 0.1.
It can be in the range of 1 to 20 μm, preferably 0.2 to 10 μm, particularly preferably 0.3 to 5 μm. When the film thickness is less than 0.1 μm, a sufficient compensation effect may not be obtained, which is not preferable. On the other hand, if the thickness exceeds 20 μm, the display may be unnecessarily colored, which is not preferable.

The apparent in-plane retardation value when viewed from the normal direction of the optically anisotropic element is 550 nm.
5 to 500 nm, preferably 1 to
It can be in the range of 0 to 300 nm, particularly preferably 15 to 150 nm. When the apparent retardation value is less than 5 nm, a sufficient viewing angle expanding effect may not be obtained, which is not preferable. On the other hand, if it is larger than 500 nm, unnecessary coloring may occur on the display when viewed obliquely, which is not preferable. The apparent in-plane retardation value can be determined in the same manner as a method of measuring the in-plane retardation value of a normal optical film such as a retardation film using an ellipsometer or a Berek compensator or the like. it can.

The average tilt angle of the optically anisotropic element is:
Usually, it can be in the range of 5 to 70 degrees, preferably 10 to 65 degrees. If the average tilt angle is out of the above range, a sufficient viewing angle expanding effect may not be obtained, which is not preferable. In the specification of the present application, the average value of the angle between the director of the liquid crystal substance molecules and the element plane in the element film thickness direction is defined as the average tilt angle.
The average tilt angle can be determined using a crystal rotation method.

The liquid crystal material having optically positive uniaxiality as a raw material of the optically anisotropic element is not particularly limited as long as it forms the hybrid alignment and has the above parameters. For example, a substance containing a low-molecular liquid crystal substance, a high-molecular liquid crystal substance, or a mixture thereof which can exhibit various nematic liquid crystal phases can be used. The liquid crystal material as the raw material of the optically anisotropic element may be any one as long as the finally obtained composition forms a desired alignment, and a single or plural kinds of low-molecular and / or high-molecular liquid crystal substances, It may be a composition comprising a single or plural kinds of low-molecular and / or high-molecular non-liquid crystalline substances and various additives. Specifically, for example, there are liquid crystal materials described in JP-A-7-20434 or JP-A-10-186356.

In the above-described optically anisotropic element, the magnitude of the vector projected onto the element plane of the director of a liquid crystal material having an optically negative uniaxial property such as a discotic liquid crystal material changed in the film thickness direction. It has a hybrid orientation.

FIG. 2 schematically shows an example of the hybrid orientation. In the orientation shown in FIG. 2, the direction of the director of the liquid crystal material is almost perpendicular to the direction of the regulating force near the interface A to which the orientation regulating force is given by rubbing or the like, but becomes closer to the direction of the interface B. The direction of the director is approaching horizontal with respect to the interface.

The film thickness of the optically anisotropic element is usually 0.1.
It can be in the range of 1 to 20 μm, preferably 0.2 to 10 μm, particularly preferably 0.3 to 5 μm. When the film thickness is less than 0.1 μm, a sufficient compensation effect may not be obtained, which is not preferable. On the other hand, if the thickness exceeds 20 μm, the display may be unnecessarily colored, which is not preferable.

The apparent retardation value of the above-described optically anisotropic element is usually 5 for a 550 nm monochromatic light.
It can be in the range of -500 nm, preferably 10-300 nm, particularly preferably 15-150 nm. When the apparent retardation value is less than 5 nm, a sufficient viewing angle expanding effect may not be obtained, which is not preferable. On the other hand, if it is larger than 500 nm, unnecessary coloring may occur on the display when viewed obliquely, which is not preferable.

The average tilt angle of the optically anisotropic element is:
Usually, it can be in the range of 20 to 85 degrees, preferably 25 to 80 degrees, and more preferably 30 to 75 degrees. If the average tilt angle is out of the above range, a sufficient viewing angle expanding effect may not be obtained, which is not preferable.

The liquid crystal material capable of exhibiting a discotic liquid crystal phase, which is a raw material of the optically anisotropic element, is not particularly limited as long as it has the above-mentioned parameters while forming the hybrid alignment. For example, various low-molecular liquid crystal substances, high-molecular liquid crystal substances, or mixtures thereof can be used. The liquid crystal material as the raw material of the optically anisotropic element may be any one as long as the finally obtained composition forms a desired alignment, and a single or plural kinds of low-molecular and / or high-molecular liquid crystal substances, It may be a composition comprising a single or plural kinds of low-molecular and / or high-molecular non-liquid crystalline substances and various additives. More specifically, for example,
Liquid crystal materials described in JP-A-27284, JP-A-8-50206 or JP-A-8-334621 are exemplified.

In the above-described optically anisotropic element, the magnitude of the vector projected onto the element plane of the director of a liquid crystal material having optically positive uniaxiality such as a nematic liquid crystal material changes in the film thickness direction, and It has a structure in which the direction of the projection vector is rotated.

FIG. 3 schematically shows an example of the twisted hybrid orientation. In the orientation shown in FIG. 3, the direction of the director of the liquid crystal material is along the direction of the regulating force near the interface A to which the orientation regulating force is given by rubbing or the like, but as the orientation approaches the interface B, the director direction increases. The direction approaches perpendicular to the interface and the direction of the projection vector on the element plane of the director is rotating.

The film thickness of the optically anisotropic element is usually 0.1.
It can be in the range of 1 to 20 μm, preferably 0.2 to 10 μm, particularly preferably 0.3 to 5 μm. When the film thickness is less than 0.1 μm, a sufficient compensation effect may not be obtained, which is not preferable. On the other hand, if the thickness exceeds 20 μm, the display may be unnecessarily colored, which is not preferable.

The apparent retardation value of the above-mentioned optically anisotropic element is usually 5 for 550 nm monochromatic light.
It can be in the range of -500 nm, preferably 10-300 nm, particularly preferably 20-100 nm. When the apparent retardation value is less than 5 nm, a sufficient viewing angle expanding effect may not be obtained, which is not preferable. On the other hand, if it is larger than 500 nm, unnecessary coloring may occur on the display when viewed obliquely, which is not preferable.

The average tilt angle of the optically anisotropic element is:
Usually, it can be in the range of 5 to 70 degrees, preferably 10 to 65 degrees. If the average tilt angle is out of the above range, a sufficient viewing angle expanding effect may not be obtained, which is not preferable.

The twist angle of the above-mentioned optically anisotropic element can be usually 3 to 180 degrees, preferably 5 to 120 degrees, particularly preferably 10 to 90 degrees.

The nematic liquid crystal material used as a raw material of the optically anisotropic element is not particularly limited as long as it forms the twisted hybrid alignment and has the above parameters. For example, various low-molecular liquid crystal substances, high-molecular liquid crystal substances, or mixtures thereof can be used. The liquid crystal material as the raw material of the optically anisotropic element may be any one as long as the finally obtained composition forms a desired alignment, and a single or plural kinds of low-molecular and / or high-molecular liquid crystal substances, It may be a composition comprising a single or plural kinds of low-molecular and / or high-molecular non-liquid crystalline substances and various additives. The liquid crystal material as a raw material of the optically anisotropic element includes a material having a chiral substituent as at least one of the liquid crystal material, the non-liquid crystal material, and an additive to induce twist alignment in addition to hybrid alignment. thing,
Alternatively, a mixture further containing a chiral agent can be used. Specifically, for example, a liquid crystal material described in JP-A-7-140326 or the like can be used.

In the above-described optically anisotropic element, the magnitude of a vector projected onto the element plane of the director of a liquid crystal material having an optically negative uniaxial property such as a discotic liquid crystal material changes in the film thickness direction, In addition, it has a structure in which the direction of the projection vector is rotated.

FIG. 4 schematically shows an example of the twisted hybrid orientation. In the orientation shown in FIG. 4, the direction of the director of the liquid crystal material is substantially perpendicular to the direction of the regulating force near the interface A to which the orientation regulating force is applied by rubbing or the like, but becomes closer to the direction of the interface B. The direction of the director approaches horizontal with respect to the interface, and the direction of the projection vector of the director onto the element plane is rotated.

The film thickness of the above-mentioned optically anisotropic element is usually 0.1.
It can be in the range of 1 to 20 μm, preferably 0.2 to 10 μm, particularly preferably 0.3 to 5 μm. When the film thickness is less than 0.1 μm, a sufficient compensation effect may not be obtained, which is not preferable. On the other hand, if the thickness exceeds 20 μm, the display may be unnecessarily colored, which is not preferable.

The apparent retardation value of the above-mentioned optically anisotropic element is usually 5 for a monochromatic light of 550 nm.
It can be in the range of -500 nm, preferably 10-300 nm, particularly preferably 20-100 nm. When the apparent retardation value is less than 5 nm, a sufficient viewing angle expanding effect may not be obtained, which is not preferable. On the other hand, if it is larger than 500 nm, unnecessary coloring may occur on the display when viewed obliquely, which is not preferable.

The average tilt angle of the optically anisotropic element is:
Usually, it can be in the range of 20 to 85 degrees, preferably 25 to 80 degrees, and more preferably 30 to 75 degrees. If the average tilt angle is out of the above range, a sufficient viewing angle expanding effect may not be obtained, which is not preferable.

The twist angle of the optically anisotropic element can be usually 3 to 180 degrees, preferably 5 to 120 degrees, particularly preferably 10 to 90 degrees.

The discotic liquid crystal material used as a raw material of the optically anisotropic element is not particularly limited as long as it forms the twisted hybrid alignment and has the above parameters. For example, various low molecular liquid crystal materials,
A liquid crystal polymer material, a mixture thereof, or the like can be used. The liquid crystal material as the raw material of the optically anisotropic element may be any one as long as the finally obtained composition forms a desired alignment, and a single or plural kinds of low-molecular and / or high-molecular liquid crystal substances, It may be a composition comprising a single or plural kinds of low-molecular and / or high-molecular non-liquid crystalline substances and various additives. The liquid crystal material as a raw material of the optically anisotropic element includes a material having a chiral substituent as at least one of the liquid crystal material, the non-liquid crystal material, and an additive to induce twist alignment in addition to hybrid alignment. Or a composition further blended with a chiral agent can be used. Specifically, for example, Japanese Patent Application Laid-Open No. 9-26572
And Japanese Patent Application Laid-Open No. 10-333139.

The phase type diffraction element layer used in the liquid crystal display device of the present invention can be provided on one or both outside the liquid crystal cell surface. That is, at least one sheet is provided outside the liquid crystal cell surface.

The diffractive element layer is a layer that exhibits a phenomenon that, when a wave represented by light is interrupted by an obstacle, wraps around a shaded portion of the background, that is, a layer that exhibits a phenomenon in which light bends. Say. As the phase type diffraction element layer, for example, a periodic groove is provided on a substrate that does not absorb light, and the thickness of the substrate is changed, or a periodic refractive index is provided inside a layer having a uniform thickness. And a distribution having an appropriate distribution. For example,
Plastic film with irregularities periodically, 2
Periodic phase separation of two kinds of polymers, one consisting of smectic liquid crystal molecules having a helical structure, one in which liquid crystals are periodically dispersed in a polymer matrix, and two kinds of alignment state of liquid crystals are periodically distributed And a hologram. In the liquid crystal display device of the present invention,
The viewing angle characteristic is improved by using the property of the phase-type diffraction element layer to bend light and distributing transmitted light at a good angle such as brightness, contrast, and gradation characteristics of the liquid crystal cell to a bad angle in the periphery. The phase type diffractive element layer has a portion that does not transmit light, so that the amount of transmitted light is reduced, and the loss of transmitted light is smaller than that of an amplitude type diffractive element that has a low diffraction efficiency in principle. Further, among the phase type diffraction elements, those made of a liquid crystalline film are particularly preferable because the refractive index difference can be set large.

The diffraction angle of the phase type diffraction element layer can be adjusted by adjusting the structure of the element and the lattice spacing such as the refractive index distribution. The lattice spacing is not particularly limited, but is preferably 0.2 to 20 μm, and 0.3 to 10 μm.
m is more preferred. The lattice spacing may be uniform in the element or may vary depending on the location in the element.

The structure of the grating in the phase type diffraction element layer is as follows:
There is no particular limitation as long as a diffraction phenomenon occurs, and it may be one-dimensional, two-dimensional, or three-dimensional, or may be inclined with respect to the layer. Further, the lattice spacing and the lattice structure may be either continuous or discontinuous in the device.

The position where the phase type diffraction element layer is provided is not particularly limited as long as the position is outside the surface of the liquid crystal cell, but the position outside the polarizing layer on the display side and / or between the liquid crystal cell and the optical compensation layer. Preferably, one or more sheets are provided between the polarizing layer and the optical compensation layer on the display side.

The phase type diffraction element layer is preferably a layer having a smectic liquid crystal phase having a helical structure or a layer having at least a film in which the orientation is fixed.

The smectic liquid crystal phase is a liquid crystal phase in which molecules constituting the liquid crystal phase have a layer structure that can be called a one-dimensional crystal or a two-dimensional liquid. Examples of the smectic liquid crystal phase include a smectic A phase (SmA phase), a smectic B phase (SmB phase), and a smectic C phase (SmC phase).
Phase), smectic E phase (SmE phase), smectic F
Phase (SmF phase), smectic G phase (SmG phase), smectic H phase (SmH phase), smectic I phase (SmI phase)
Phase), smectic J phase (SmJ phase), smectic K
Phase (SmK phase), smectic L phase (SmL phase) and the like, and among them, particularly, smectic C phase, smectic I phase, smectic F phase, smectic J phase, smectic G phase, smectic K phase, or smectic H
A phase, such as a phase, in which rod-like molecules are inclined with respect to the layer normal direction of the liquid crystal phase is preferable.

In particular, among the above smectic liquid crystal phases, they exhibit an optical activity such as a chiral smectic C phase (SmC ^* phase), a chiral smectic I phase (SmI ^* phase) or a chiral smectic F phase (SmF ^* phase) and exhibit ferroelectric properties. It indicates a chiral smectic C _a phase (SmC _a ^* phase), chiral smectic I _a phase (SmI _a ^* phase) or chiral smectic F _a phase (SmF _a ^* phase) antiferroelectric exhibit optical activity, such as the Or chiral smectic Cγ phase (SmC
gamma ^* phase), chiral smectic Iγ phase (SmIγ ^* phase) or chiral smectic Fγ phase (SmFγ ^* phase) or the like shows the ferrielectric exhibit optical activity of various chiral smectic phase is a smectic phase having a helical structure Is particularly preferred. However, being chiral is not an essential condition. For example, J. Mater. Chem.
996) and J. Mater. Chem. 7, pp. 1307 (199).
7 years) and the like, and may be an achiral smectic phase having a helical structure.

Among the above-mentioned various smectic phases, the most preferred one is from the viewpoint of the stability of the helical structure, the easiness of changing the helical pitch, the ease of synthesis, and the ease of orientation due to low viscosity. Is chiral smectic C
Phase or a chiral smectic C _A phase.

The helical structure means that the arrangement of molecules constituting the liquid crystal phase changes little by little in each layer, and a structure in which the arrangement of molecules is rotated as a whole is formed. Examples of the change in the arrangement of the molecules include a structure in which the direction of the tilt in the molecular long axis direction with respect to the normal direction of the layer in the smectic liquid crystal phase is gradually rotated in the adjacent layers.

The center axis of the helix in the helix structure is called a helix axis, and the distance in the helix axis direction for one rotation of the helix is called the helix pitch. When light enters the helical structure, the angle formed by the incident light and the molecule differs depending on the position in the helix, regardless of the incident angle, so that the refractive index felt by the incident light varies. As a result, the light feels a periodic distribution of the refractive index, and diffraction occurs.

The direction of diffraction when light is allowed to pass through the helical structure is, for example, a phase-type diffraction element layer having a helical structure in which the helical axis is parallel to the surface of the phase-type diffraction element layer. When formed, light is normally diffracted in the direction of the helical axis when it is incident perpendicular to the plane of the layer.

The direction of the helical axis in the liquid crystal display device of the present invention is not particularly limited, and may be a direction that functions as a desired phase-type diffraction element layer and provides a viewing angle characteristic improving effect. For example, it may be parallel, perpendicular, or inclined with respect to the display surface of the liquid crystal display device, and the inclination may change discontinuously or continuously.

The direction of the helical axis may be microscopically composed of oriented regions (domains) having an orientation, and macroscopically, a multi-domain phase having various directions of the helical axis may be used.
Monodomain phases all aligned in the same direction may be used. For example, by providing a phase-type diffraction element layer such that the helical axis is oriented in the vertical direction of the screen on the surface of the liquid crystal display device, a liquid crystal display device having improved viewing angle characteristics in the vertical direction of the screen can be obtained. In addition, two or more phase type diffraction elements are provided such that two phase type diffraction element layers, one with the helical axis facing the vertical direction of the screen and the other with the helical axis facing the left and right direction, are intersected. By providing an element layer,
A liquid crystal display device having improved viewing angle characteristics by waving in a plurality of directions or all directions can be obtained.

The angle of diffraction when light passes through the helical structure is determined by the distance of the periodic distribution of the refractive index corresponding to the lattice spacing, that is, the helical pitch. Therefore, the diffraction angle of the phase type diffraction element layer can be easily adjusted by adjusting the helical pitch.

The helical pitch of the helical structure is not particularly limited, but is preferably 0.2 to 20 μm, and 0.3 to 20 μm.
10 μm is more preferred. The helical pitch may be constant in the phase type diffraction element layer, but may be different depending on the position in the layer.

The helical pitch can be easily adjusted by adjusting the alignment conditions such as temperature, adjusting the optical purity of the optically active site, the compounding ratio of the optically active substance, and the like in the production of the phase type diffraction element layer. Can be adjusted.

In the phase type diffraction element layer, the orientation of the smectic liquid crystal phase having the helical structure may be fixed or non-fixed.

When the orientation of the smectic liquid crystal phase having a helical structure is fixed, it means that the orientation is not disturbed under the conditions in which the phase type diffraction element layer is used, and the performance as the phase type diffraction element layer is lost. It means that it is in a state that can not be done. In the liquid crystal display device of the present invention, it is preferable that the orientation of the liquid crystal phase is fixed by some means from the viewpoint of easiness of production and high practicality.

Examples of the phase type diffraction element in which the orientation of the smectic liquid crystal phase having a helical structure is not fixed include, for example, a smectic liquid crystal having a helical structure at room temperature between two substrates separately from the liquid crystal cell. A liquid crystal material having a phase is injected, and a cell having the helical structure is provided.

On the other hand, as the phase type diffractive element layer in which the orientation of the smectic liquid crystal phase having a helical structure is fixed, for example, (A) a liquid crystal material exhibiting a smectic liquid crystal phase having a helical structure is prepared by using a liquid crystal material having a glass transition temperature or higher. A liquid crystal material exhibiting a smectic liquid crystal phase having a helical structure; A film formed by forming a liquid crystal phase by setting the temperature to the liquid crystal phase, polymerizing the liquid crystal phase while maintaining the orientation of the liquid crystal phase, and fixing the orientation of the liquid crystal phase can be used.

The liquid crystal material of the phase type diffraction element having the alignment structure of the smectic liquid crystal phase having the helical structure is not particularly limited as long as it has the smectic liquid crystal phase having the helical structure in a phase series. , Various low-molecular liquid crystal materials such as those listed below, high-molecular liquid crystal materials,
Alternatively, a mixture thereof can be used.

The liquid crystal display device according to the present invention comprises:
In addition to the polarizing layer, the phase type diffraction element layer, and the optical compensation layer, other diffraction element layers such as a protective layer, an antireflection film, a prism sheet, a diffusion sheet, a light guide plate, a backlight, and an amplitude type diffraction element layer, or these And other layers such as an adhesive layer or an adhesive layer for bonding.

The protective layer is not particularly restricted but includes various transparent plastic films.
By further including the protective layer, effects such as surface protection, increased strength, and improved environmental reliability can be obtained.

The prism sheet, the diffusion sheet, and the light guide plate are not particularly limited, and include those used in a known backlight system.

The manufacturing method of the liquid crystal display device of the present invention is not particularly limited, and the polarizing layer, the optical compensation layer, the phase type diffraction element layer, and the outside of the liquid crystal cell assembled by a known method are required. And other layers provided according to the order in which a desired structure is obtained.

On a transparent electrode substrate, a polarizing layer, an optical compensation layer,
The method of providing the phase-type diffraction element layer and other layers provided as necessary is not particularly limited, and a laminate is formed by laminating with an adhesive or a pressure-sensitive adhesive or the like, and the laminate is formed in an appropriate size. After being cut into pieces, the liquid crystal display device of the present invention including the polarizing layer, the optical compensation layer, the phase-type diffraction element layer, and the like can be assembled by attaching and attaching the liquid crystal cell to the liquid crystal cell. On the other hand, on the polarizing layer of the liquid crystal display having a structure including the optical compensation layer and the polarizing layer on both sides of the liquid crystal cell already assembled, the film of the phase type diffraction element is coated with an adhesive or an adhesive as necessary. The liquid crystal display device of the present invention can also be assembled by bonding such as by pasting through. In this case, the phase-diffraction element to which the adhesive or the adhesive is applied, which is suitable for pasting, is prepared in advance, and by pasting it, the already assembled liquid crystal display can be easily prepared according to the present invention. A liquid crystal display device can be obtained. Furthermore, the effect of improving the viewing angle characteristics and the like can be obtained as the liquid crystal display device of the present invention simply by placing it on the liquid crystal display without using an adhesive or an adhesive. The above mounting operation can be performed by a polarizing plate maker, a liquid crystal display maker, and also by a liquid crystal display user.

The polarizing layer constituting the liquid crystal display device of the present invention,
The method for preparing each layer such as the optical compensation layer and the phase type diffraction element layer is not particularly limited.

In particular, as a method for forming a phase type diffraction element layer in which the orientation of the smectic liquid crystal phase having a helical structure is fixed, a liquid crystal material containing a liquid crystal material is developed between two interfaces, and After the material is oriented to a smectic liquid crystal phase having a helical structure, a method of fixing the orientation can be used. Here, as a method for fixing the orientation, (A) a liquid crystal material exhibiting a smectic liquid crystal phase having a helical structure is formed at a temperature equal to or higher than the glass transition temperature to form the liquid crystal phase, and then cooled. (B) a method in which a liquid crystal material exhibiting a smectic liquid crystal phase having a helical structure is heated to a temperature at which the liquid crystal phase is exhibited to form a liquid crystal phase, and then the orientation of the liquid crystal phase is maintained. And the like.

The liquid crystal material is not particularly limited as long as it has a smectic liquid crystal phase having the helical structure in a phase series and can fix its orientation. For example, various low-molecular liquid crystal substances, high-molecular liquid crystal substances, or mixtures thereof can be used. In addition, the liquid crystal material may be any as long as the composition finally obtained exhibits desired liquid crystallinity and orientation, and may be used alone or in combination with a plurality of low-molecular and / or high-molecular liquid crystal substances. A composition comprising a low molecular weight and / or high molecular weight non-liquid crystalline substance may be used. Further, in the liquid crystal material, for example, a surfactant, a polymerization initiator, or the like within a range that does not impair the effects of the present invention.
Various additives such as a polymerization inhibitor, a sensitizer, a stabilizer, a catalyst, a dye, a pigment, an ultraviolet absorber, and an adhesion improver can also be blended. The content ratio of the liquid crystal substance in the liquid crystal material,
Usually, it can be 30-100% by weight, preferably 50-100% by weight, more preferably 70-100% by weight.

The low-molecular liquid crystal substance contained in the liquid crystal material includes Schiff base compounds, biphenyl compounds, terphenyl compounds, ester compounds, thioester compounds, stilbene compounds, tolan compounds, azoxy compounds. , An azo compound, a phenylcyclohexane compound, a pyrimidine compound, a cyclohexylcyclohexane compound, a composition thereof, or the like.

As the polymer liquid crystal substance contained in the liquid crystal material, various kinds of main-chain polymer liquid crystal substances, side-chain polymer liquid crystal substances, or mixtures thereof can be used.

Examples of the main chain type polymer liquid crystal substance include polyesters, polyamides, polycarbonates, polyimides, polyurethanes, polybenzimidazoles, polybenzoxazoles, polybenzthiazoles, polyazomethines, and polyesteramides. System, polyester carbonate system, polyester imide system, etc., or a composition thereof. As the main-chain type polymer liquid crystal material, a mesogen group which gives liquid crystal properties and a semi-aromatic polyester polymer liquid crystal material in which bent chains such as polymethylene, polyethylene oxide and polysiloxane are alternately bonded, and a bent chain Preferably, a wholly aromatic polyester polymer liquid crystal material is not used. Further, as the side chain type polymer liquid crystal material, a polyacrylate type,
Polymethacrylate-based, polyvinyl-based, polysiloxane-based, polyether-based, polymalonate-based, polyester-based or other substances having a skeleton chain of a linear or cyclic structure with a mesogen group bonded as a side chain, or a mixture thereof And the like. As the side-chain type polymer liquid crystal substance, a substance in which a mesogen group imparting liquid crystallinity is bonded to a skeleton chain via a spacer formed of a bent chain is preferable. Also, the main chain,
Those having a molecular structure having a mesogen in both side chains are also preferable.

As the liquid crystal material, a mixture of a low-molecular liquid crystal substance and / or a high-molecular liquid crystal substance as described above and a chiral agent or an optically active unit is introduced to form a smectic liquid crystal phase having a desired helical structure. Preferred for presentation. For example, smectic C phase, smectic I phase,
By blending a chiral agent or introducing an optically active unit into the liquid crystal material exhibiting a smectic F phase or the like, a helical structure such as a chiral smectic C phase, a chiral smectic I phase, or a chiral smectic F phase is exhibited. A liquid crystal substance which can exhibit an easy chiral smectic phase can be obtained. The amount of such a chiral agent,
By appropriately adjusting the amount of the optically active unit introduced, the optical purity, the temperature conditions for orientation, and the like, the characteristics of the phase-type diffraction element layer such as the helical pitch can be adjusted.

As the liquid crystal material whose orientation can be fixed by the method (A), those which can form a smectic liquid crystal phase having a desired helical structure in a liquid crystal state and can be brought into a glass state by cooling. Can be used. Usually, a liquid crystal material mainly composed of a polymer liquid crystal substance having the above properties is suitably used.

The liquid crystal material whose orientation can be fixed by the method (B) includes a group which can be polymerized by heat, light or electron beam, for example, a vinyl group, an acryl group, a methacryl group, a vinyl ether group. , Cinnamoyl group, allyl group, acetylenyl group, crotonyl group, aziridinyl group, epoxy group, isocyanate group, thioisocyanate group, amino group, hydroxyl group, mercapto group, carboxylic acid group, acyl group, halocarbonyl group, aldehyde group,
A liquid crystal material containing at least a substance having a reactive functional group such as a sulfonic acid group or a silanol group can be used.
Usually, a liquid crystal material containing a low-molecular liquid crystal substance as a main component is suitably used. In addition, these functional groups may be contained in any one or more of the liquid crystal substance and / or the non-liquid crystal substance and / or the additive. In the case of two or more substances, the same and / or different functional groups are used. Groups may be included. Also, 1
Two or more functional groups of the same type and / or different types may be contained in the type of substance.

There are no particular restrictions on the two interfaces for developing the liquid crystal material, and any of a gas phase interface, a liquid phase interface and a solid phase interface can be used. Alternatively, different interfaces may be used in combination. However, it is preferable to use two solid-phase interfaces or a combination of a solid-phase interface and a gas-phase interface from the viewpoint of practicality of the obtained product and ease of production. Further, as one of the interfaces, a surface on which a phase-type diffraction element layer is to be provided, such as a surface outside the transparent electrode substrate of the liquid crystal cell or a surface of a polarizing layer, is used as a solid phase interface, and a film is directly formed thereon. It may be formed.

Examples of the gas phase interface include an air interface and a nitrogen interface. As the liquid phase interface,
Examples thereof include water, an organic solvent, a liquid metal, a material having a liquid crystal property other than a liquid crystal material, and a polymer compound in a molten state. As the solid phase interface, polyimide, polyamide imide, polyamide, polyether imide, polyether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, Polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, methacrylic resin, polyvinyl alcohol, polyethylene, polypropylene, poly-4-methylpentene-1
Plastic film substrates such as resins, cellulose-based plastics such as triacetyl cellulose, epoxy resins, phenolic resins, and materials containing high-molecular liquid crystal substances; metal substrates such as aluminum, iron, and copper; blue plate glass, alkali glass, and alkali-free glass Glass substrates such as borosilicate glass, flint glass, and quartz glass; various substrates such as ceramic substrates; and various semiconductor substrates such as silicon wafers. Further, there can be mentioned a film provided with another film, for example, an organic film such as a polyimide film, a polyamide film, or a polyvinyl alcohol film, or a film provided with an oblique evaporation film of silicon oxide on the substrate.

These substrates can be used after being subjected to an orientation treatment as required. When using a substrate that has been subjected to an orientation treatment, the orientation of the helical structure in the obtained phase-type diffraction element can be a fixed direction defined by the orientation treatment of the substrate, but the orientation of the helical axis is not necessarily It does not always coincide with the direction of the alignment treatment of the substrate, and may be slightly shifted. Note that when a substrate that is not subjected to an orientation treatment is used, the obtained phase-type diffraction element may exhibit a multi-domain phase in which the direction of the helical axis of each domain is random. The effect as a type diffraction element can be obtained.

The orientation treatment of the substrate is not particularly limited, but includes a rubbing method, an oblique deposition method, a microgroove method, a stretched polymer film method, an LB (Langmuir-Blodgett) film method, a transfer method, and a light irradiation method. (Photoisomerization, photopolymerization, photodecomposition, etc.), peeling method and the like. In particular, a rubbing method and a light irradiation method are preferable from the viewpoint of ease of the manufacturing process.

The method for developing the liquid crystal material between the interfaces is not particularly limited, and various known methods can be used. For example, if the two substrates are used as interfaces and the liquid crystal material is added between them,
A cell can be created by using two substrates, and the liquid crystal material can be injected into the cell, or the cell can be developed by laminating the liquid crystal material on the two substrates.

In the case where one substrate and the gas phase are used as an interface, the development is performed by directly applying the liquid crystal material on the substrate or applying the liquid crystal material dissolved in an appropriate solvent to form a solution. Is preferred. In particular, it is preferable to develop by applying a solution from the viewpoint of the easiness of the manufacturing process. As the solvent, an appropriate solvent can be appropriately selected depending on the type, composition, and the like of the liquid crystal material.
Usually, chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, halogenated hydrocarbons such as orthodichlorobenzene, phenols, phenols such as parachlorophenol, benzene, toluene, xylene, methoxybenzene, 1,2-
Aromatic hydrocarbons such as dimethoxybenzene, isopropyl alcohol, alcohols such as tert-butyl alcohol, glycerin, ethylene glycol, glycols such as triethylene glycol, ethylene glycol monomethyl ether, dimethylene glycol dimethyl ether, ethyl cellosolve, Glycol ethers such as butyl cellosolve, 2-pyrrolidone, acetone, methyl ethyl ketone, ethyl acetate, N-methyl-2-pyrrolidone,
Pyridine, triethylamine, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, butyronitrile, carbon disulfide, a mixed solvent thereof and the like are used. Also,
If necessary, a surfactant may be added to the solvent in order to adjust the surface tension of the solution and improve coatability.

The concentration of the liquid crystal material in the solution can be appropriately adjusted according to the type and solubility of the liquid crystal material to be used, the thickness of the phase-diffraction element to be manufactured, and the like.
It can range from 50% by weight, preferably from 5 to 30% by weight.

The method of coating is not particularly limited.
Spin coating, roll coating, printing, immersion pulling, curtain coating, Meyer bar coating,
Doctor blade method, knife coat method, die coat method,
A gravure coating method, a microgravure coating method, an offset gravure coating method, a lip coating method, a spray coating method, or the like can be used. After the application, the solvent is removed if necessary, and the liquid crystal material can be developed on the substrate as a layer having a uniform thickness.

The method for orienting the developed liquid crystal material into a smectic liquid crystal phase having a helical structure is not particularly limited. However, when the liquid crystal material is developed at a temperature at which the liquid crystal material can have a smectic liquid crystal phase having a helical structure,
In some cases, a smectic liquid crystal phase having a helical structure is obtained simultaneously with the development. Further, once the developed liquid crystal material, a smectic liquid crystal phase having a helical structure is developed from a phase that develops at a higher temperature than the smectic liquid crystal phase having a helical structure, such as a smectic A phase, a chiral nematic phase, and an isotropic phase. Orientation can also be achieved by cooling to temperature.

At this time, if necessary, the orientation direction of the liquid crystal material can be controlled to a specific direction. This control can be performed, for example, by using, as the interface, one or more substrates that have been subjected to the alignment treatment. If two substrates are used as the interface, one of them
Only one of the sheets may be subjected to the orientation treatment, or both of the sheets may be subjected to the orientation treatment.

As an example in which two alignment-treated substrates are used, a rubbing polyimide glass or the like is used as a cell for injecting the liquid crystal material, and a thick film cell in which the liquid crystal material is not spiraled is used. By using a liquid crystal material, the liquid crystal material can be oriented in a specific direction. Alternatively, the orientation can be set to a specific direction by laminating the liquid crystal material with two plastic films that have been subjected to an orientation treatment. In these cases, when the orientation direction of the two substrates is made antiparallel (the orientation direction is opposite. For example, in the case of rubbing, the rubbing direction is opposite), the helical axis is parallel to the substrate or uniformly inclined. Structure obtained,
When they are made parallel (the orientation direction is the same), a film having a helical axis parallel to the substrate or a film having a helical axis whose inclination changes in the middle of the film thickness direction can be obtained.

Further, even without using an alignment-treated substrate, a magnetic field, an electric field, shear stress, flow, stretching, and a temperature gradient are applied to the liquid crystal material developed on the interface, so that the spiral of the phase type diffraction element can be used. The direction of the axis can be a fixed direction.

The orientation of the liquid crystal material can be fixed by the method (A) or the method (B).

In the method (A), the liquid crystal material in which the smectic liquid crystal phase having a helical structure is formed is cooled at a temperature equal to or higher than the glass transition temperature by the above method or the like until the liquid crystal material becomes a glass state. By lowering the temperature, the liquid crystal material is not brought into a crystalline state,
The orientation can be fixed in a glassy state. The means for cooling is not particularly limited, and it is possible to perform desired cooling sufficient for immobilization simply by taking out from the heating atmosphere in the development or alignment step to an atmosphere below the liquid crystal transition point, for example, to room temperature. In order to increase production efficiency, air cooling,
Forced cooling such as water cooling may be performed.

In the method (B), a polymerizable liquid crystal material containing the liquid crystal substance oriented in a smectic liquid crystal phase having a helical structure is polymerized while maintaining the orientation of the liquid crystal phase. Although there is no particular limitation on the polymerization method, thermal polymerization, photopolymerization, radiation polymerization such as γ-ray, electron beam polymerization, polycondensation, polyaddition and the like can be used. Above all, polymerization by light irradiation or electron beam irradiation using visible light or ultraviolet light which is easy to control the reaction and is advantageous in production is preferable.

The film obtained by fixing the orientation by these methods can be directly used as a phase type diffraction element layer if the surface on which the phase type diffraction element is to be provided is used as an interface. When another substrate or the like is used as the interface, the liquid crystal cell may be separated from the substrate or the like, or may be transferred to the entire substrate or to another substrate different from the substrate. The phase type diffraction element layer can be provided outside the liquid crystal cell by being mounted on an electrode substrate, an optical compensation layer, a polarizing layer, or the like.

The phase type diffraction element layer formed by the above method is
Even when the substrate subjected to the orientation treatment is removed after obtaining a film in which the direction of the helical axis is fixed to a certain direction using the substrate subjected to the orientation treatment, even if the substrate subjected to the orientation treatment is removed, the orientation is not disturbed. The element can be laminated on the liquid crystal cell substrate as an element in which the direction of the axis is defined.

The method for forming the optical compensation layer is as follows.
In the case of the (a) non-liquid crystal film, the stretching, film formation, rolling, drawing, solid extrusion, blow molding, and known molding processing operations such as vapor deposition are performed on the non-liquid crystal film material to form an optically anisotropic element. A method of producing the resultant and using it as an optical compensation layer is exemplified. In the case of the liquid crystal film (b),
(b) A liquid crystal material capable of forming a liquid crystal film is developed between two interfaces, and after the liquid crystal material is oriented in a desired state, the orientation is fixed if necessary to form an optically anisotropic element. A method of producing the resultant and using it as an optical compensation layer is exemplified.

As the interface for the development and the method for developing the interface, the same ones as those used for the formation of the phase type diffraction element layer can be used. Further, if necessary, the orientation direction is controlled by using the interface subjected to the orientation treatment, and an optical anisotropic element having a specific orientation such as the above-mentioned optical anisotropic element can be obtained.

As for the method of fixing the orientation, similarly to the fixing in the formation of the phase type diffraction element layer, after the liquid crystal material or the like is oriented at a temperature equal to or higher than the glass transition temperature,
A method in which the alignment is fixed by cooling to a glass state by cooling, or a method in which the aligned liquid crystal material or the like is polymerized or cross-linked while maintaining the alignment to fix the alignment.

Next, a specific example of an embodiment of the liquid crystal display device of the present invention will be briefly described with reference to the drawings.

In the example shown in FIG. 5, the optical compensation layer 3A, the polarizing layer 2A, and the phase type diffractometer are disposed on both sides of the liquid crystal cell 4 on the display side (upward direction in the drawing) via an adhesive layer or an adhesive layer 5. The element layers 1A are sequentially provided in this order. On the other hand, on the opposite side of the liquid crystal cell 4, a polarizing layer 2B is provided via an adhesive layer or an adhesive layer 5, and a backlight system 6 including a prism sheet, a diffusion sheet, a light guide plate and the like is provided. By thus providing the phase type diffraction element layer and the optical compensation layer in combination on the display side, a liquid crystal display device having an effect of improving viewing angle characteristics and the like can be obtained.

In the example shown in FIG. 6, an optical compensation layer 3B is provided between the liquid crystal cell 4 and the polarizing layer 2B in the example shown in FIG.

In the example shown in FIG. 7, two phase type diffraction element layers 1B and 1C are provided in place of the single phase type diffraction element 1A in the example of FIG. These phase type diffraction element layers 1B and 1C may have the same or different parameters. When using the same one, two layers may be combined in the vertical direction, the horizontal direction, the oblique direction, and the like of the screen in two directions. The viewing angle characteristics can be improved over a plurality of directions by using a combination of the two. In the example of FIG. 7, two phase-type diffraction element layers are combined, but the number of phase-type diffraction element layers to be combined is not limited to this, and three or more phase-type diffraction element layers can be combined. When three or more layers are used in combination, three layers having the same diffraction direction, such as a vertical direction, a horizontal direction, and a diagonal direction, may be used. The viewing angle characteristics can be improved over a plurality of azimuths by using a combination of two or more of those oriented in the direction.

In the example shown in FIG. 8, an optical compensation layer 3B is further provided between the liquid crystal cell 4 and the polarizing layer 2B in the example shown in FIG.
It has two phase-type diffraction element layers and two optical compensation layers.

In the example shown in FIG. 9, the optical compensation layer 3C, the phase-type diffraction element layer 1D, and the polarizing layer 2C are provided on the display side (upward direction in the drawing) of the liquid crystal cell 4 via an adhesive layer or an adhesive layer 5. They are provided sequentially in this order. By thus providing the phase type diffraction element layer between the liquid crystal cell and the polarizing layer, a liquid crystal display device having an effect of improving viewing angle characteristics and the like can be obtained.

In the example shown in FIG. 10, an optical compensation layer 3D is provided between the liquid crystal cell 4 and the polarizing layer 2B in the example shown in FIG. 9 via an adhesive layer or an adhesive layer 5.

In the example shown in FIG. 11, two phase type diffraction element layers 1E and 1F are provided in place of the one phase type diffraction element layer 1D in the example of FIG. These phase type diffraction element layers 1E and 1F may have the same or different parameters as in the example of FIG. In the case of using the same one, two layers in which the diffraction direction is the same in the vertical direction, the horizontal direction, and the oblique direction of the screen may be combined in two layers, but the directions are different. By using a combination of the two, the viewing angle characteristics can be improved over a plurality of directions.
In the example of FIG. 11, two phase-type diffraction element layers are combined, but the number of phase-type diffraction element layers to be combined is not limited to this, and three or more phase-type diffraction element layers can be combined. When three or more layers are used in combination, three layers having the same diffraction direction, such as a vertical direction, a horizontal direction, and a diagonal direction, may be used. The viewing angle characteristics can be improved over a plurality of azimuths by using a combination of two or more of those oriented in the direction.

In the example shown in FIG. 12, an optical compensation layer 3D is further provided between the liquid crystal cell 4 and the polarizing layer 2B in the example shown in FIG. And the two optical compensation layers.

In the example shown in FIG. 13, a phase type diffraction element layer 3A and a polarizing layer 2D are sequentially provided in this order on the display side (upward direction in the drawing) of the liquid crystal cell 4 via an adhesive layer or an adhesive layer 5. And a direct-phase diffraction element layer 1
G is provided. For example, as described above, the liquid crystal display device of such an embodiment can be configured by simply placing a phase-type diffraction element layer on a liquid crystal display including one optical compensation layer such as a commercially available product. it can.
When preparing the phase-type diffraction element layer, a polarizing layer is used as one of the interfaces, and a liquid crystal material is spread thereon to form a composite layer in which the phase-type diffraction element layer is formed on the polarization layer. After that, the liquid crystal display device shown in FIG. 13 can be manufactured even if it is attached on the optical compensation layer.

In the example shown in FIG. 14, an optical compensation layer 3B is provided between the liquid crystal cell 4 and the polarizing layer 2B in the example shown in FIG. For example, as described above, the liquid crystal display device of such an embodiment can be configured by merely placing a phase-type diffraction element layer on a liquid crystal display including two optical compensation layers such as a commercially available product. it can. When preparing the phase-type diffraction element layer, a polarizing layer is used as one of the interfaces, and a liquid crystal material is spread thereon to form a composite layer in which the phase-type diffraction element layer is formed on the polarization layer. After that, the liquid crystal display device shown in FIG. 14 can be manufactured even when the liquid crystal display device is attached on the optical compensation layer.

[0125]

The liquid crystal display device of the present invention, by including the optical compensation layer and the phase type diffraction element layer, can solve the problems caused by the viewing angle dependence of the liquid crystal display, such as blackening, grayscale inversion and white spots. And has an unprecedented wide viewing angle. In addition, it has an extremely high industrial value, for example, it can be easily manufactured at low cost and can have a large screen.

[0126]

The present invention will be described in more detail with reference to the following examples.
The present invention is not limited to these.

In the examples, the measurement of the intrinsic viscosity, the determination of the liquid crystal phase series, the measurement of the refractive index, the measurement of the film thickness, and the evaluation of the gradation characteristics were performed according to the following methods. (1) Measurement of Intrinsic Viscosity Using an Ubbelohde viscometer, it was measured in a phenol / tetrachloroethane (60/40 weight ratio) mixed solvent at 30 ° C. (0.5 g / dL). (2) Determination of liquid crystal phase series Determined by DSC (Perkin Elmer DSC-7) measurement and observation with an optical microscope (BH2 polarizing microscope manufactured by Olympus Optical Co., Ltd.). (3) Measurement of Refractive Index The refractive index was measured using an Abbe refractometer (Type-4, manufactured by Atago Co., Ltd.). (4) Film thickness measurement Dektak, a surface profile measuring device manufactured by Japan Vacuum Engineering Co., Ltd.
Model 3030ST was used. Further, a method of measuring the film thickness from the data of the refractive index and the interference wave measurement (UV-visible / near-infrared spectrophotometer V-570 manufactured by JASCO Corporation) was also used. (5) Evaluation of gradation characteristics Test panel: ZLI-479 manufactured by Merck as a liquid crystal material
2 and chiral agent, cell gap 4.7 μm, Δ
A TN type liquid crystal cell having an nd of 440 nm and a twist angle of 90 degrees (left twist) was produced. The polarizing plate was arranged so that the rubbing direction was perpendicular to the transmission axis.

A voltage was applied to the test panel with a rectangular wave of 300 Hz. 1.92V white display, 6V black display
The drive voltage for each gradation was set so that the transmittance was divided into eight between the white transmittance and the black transmittance. Measurement of transmittance from all directions using FEP optical system DV manufactured by Hamamatsu Photonics Co., Ltd.
The evaluation was performed using S-3000 to evaluate the gradation characteristics.

[0129]

Example 1 (Preparation of optical compensation layer (i)) JP-A-10-1
No. 86356, referring to 6-hydroxy-2-
Naphthoic acid 100 mmol, terephthalic acid 100 mmol
l, 50 mmol of chlorohydroquinone and 50 mmol of tert-butylcatechol were used as monomers to synthesize liquid crystalline polyester A by melt polymerization (intrinsic viscosity: 0.1).
30 dL / g).

A 10 wt% solution of the liquid crystalline polyester A in tetrachloroethane was prepared, applied to a glass substrate having a rubbing polyimide film by spin coating, and the solvent was removed at 60 ° C. on a hot plate. Then, after orientation was performed by heat treatment at 220 ° C. for 15 minutes in a thermostatic oven, it was taken out and cooled at room temperature to fix the orientation of the liquid crystalline polyester, and an optically anisotropic element was obtained as a film on a glass substrate. In the obtained optically anisotropic element, the hybrid orientation was fixed, the film thickness was 0.7 μm, the apparent in-plane retardation was 90 nm, and the average tilt angle was 30 degrees. The optically anisotropic element and a negative C-oriented triacetyl cellulose (TAC) film having a thickness of 80 μm were bonded with an adhesive to obtain an optical compensation layer (i). (Preparation of phase type diffraction element layer (i)) 200 mmol of dimethyl 4,4′-biphenyldicarboxylate, (R) -2-methyl-1,4-butanediol (enantiomeric excess,
(ee = 60.0%) Using 120 mmol, 1,6-hexanediol 80 mmol, and tetra-n-butyl orthotitanate as a catalyst, a liquid crystalline polyester B was synthesized by melt polymerization at 220 ° C. for 2 hours ( Intrinsic viscosity 0.18 dL / g).

A 10 wt% tetrachloroethane solution of the liquid crystalline polyester B was prepared, applied to a glass substrate having a rubbing polyimide film by a spin coating method, and the solvent was removed at 60 ° C. on a hot plate. Next, after heat-treating at 180 ° C. for 10 minutes in a thermostat to orientate in the smectic A phase, the temperature is lowered at a rate of 4 ° C./min to 120 ° C., which is the temperature for orienting to the chiral smectic C phase, taken out of the thermostat and cooled to room temperature Then, the orientation of the liquid crystalline polyester was fixed, and a phase-type diffraction element layer (i) composed of an immobilized polyester film was obtained as a film on a glass substrate. In the obtained phase-type diffraction element layer (i), the glass was fixed with a chiral smectic C phase (SmC phase) having a helical structure, and had a uniform film thickness (1.1 μm). Observation with a polarizing microscope and observation of the cross section of the film with an electron microscope revealed that the helical pitch of the helical structure formed on the film having a helical structure was about 0.8 μm. The helical axis was inclined about 15 degrees from the substrate surface in the film thickness direction. The direction of the helical axis in the film plane did not coincide with the rubbing direction and was shifted clockwise by about 14 degrees. (Production and evaluation of liquid crystal display device) Obtained optical compensation layer
(i) Using two sheets, one phase-type diffraction element layer (i) and the test panel, a TN-type liquid crystal display device having the same mode as the liquid crystal display device shown in FIG. The properties were evaluated. As a result, it was found that a display having excellent viewing angle characteristics and substantially no inversion region was obtained.

[0132]

Comparative Example 1 A TN-type liquid crystal display of the embodiment shown in FIG. 15 was carried out in the same manner as in Example 1 except that the optical compensation layer (i) and the phase type diffraction element layer (i) were not used. A device was manufactured, and the gradation characteristics were evaluated in the same manner as in Example 1. As a result, it was found that the viewing angle characteristics of this liquid crystal display device were significantly inferior to those of the liquid crystal display device of Example 1.

[0133]

Example 2 (Preparation of Optical Compensation Layer (ii))

[0134]

Embedded image

JP-A-8-334621, JP-A-7-334
A liquid crystal material of the formula (1) was synthesized with reference to JP-A-135762. In the formula (1), the numbers next to the parentheses indicate the molar composition ratio. That is, in the liquid crystal material of the formula (1), two kinds of side chains are ester-bonded to the nucleus of the hexavalent discotic liquid crystal molecule in an equal proportion. 15% by weight of this liquid crystal material, 0.3% by weight of Irgacure 907 (trade name, manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and Kayacure DETX (trade name, manufactured by Nippon Kayaku) as a sensitizer
0.03% by weight, and Megafac F as a surfactant
-144D (trade name, manufactured by Dainippon Ink) 0.05% by weight
To prepare a triethylene glycol dimethyl ether solution. The solution was applied by a spin coating method on a negative C-oriented triacetyl cellulose (TAC) substrate having a thickness of 80 μm and having a rubbed polyvinyl alcohol alignment film, and the solvent was removed at 60 ° C. Next, after heat treatment for 10 minutes in a thermostat at 120 ° C., the product was taken out at room temperature. After quickly purging with nitrogen, 12
The alignment of the liquid crystal material was fixed by photopolymerization using an ultraviolet irradiation device having a high-pressure mercury lamp of 0 W / cm at an irradiation energy of 600 mJ / cm ² . In the obtained film on the TAC substrate, the hybrid orientation was fixed, the film thickness was 1.2 μm, the apparent in-plane retardation was 45 nm, and the average tilt angle was 45 degrees. Accordingly, an optical compensation layer (ii) comprising an optically anisotropic element having a fixed hybrid orientation and an optically anisotropic element having a negative C orientation as a substrate was obtained. (Production and Evaluation of Liquid Crystal Display Device) Using the two optical compensation layers (ii), one phase-type diffraction element layer (i) produced in Example 1, and the test panel, the liquid crystal shown in FIG. When a TN-type liquid crystal display device having the same mode as that of the display device was manufactured and its gradation characteristics were evaluated, a display having excellent viewing angle characteristics and substantially no inversion region was obtained as compared with the liquid crystal display device of Comparative Example 1. I understood.

[0136]

Embodiment 3 (Preparation of Optical Compensation Layer (iii)) JP-A-7-1
With reference to Japanese Patent No. 40326, 90 mmol of dimethyl 4,4′-biphenyldicarboxylate, 10 terephthalic acid 10
mmol, (s) -2-methyl-1,4-butanediol (enantiomeric excess, ee = 95.0%) 100
The liquid crystalline polyester C was synthesized by melt polymerization at 220 ° C. for 2 hours using mmol and tetra-n-butyl orthotitanate as a catalyst (intrinsic viscosity 0.2
0 dL / g).

Liquid crystalline polyester A prepared in Example 1
A 99.5: 0.5 (weight ratio) mixture of the above and a liquid crystalline polyester C was prepared in a 10 wt% tetrachloroethane solution, and the solution was applied on a glass substrate having a rubbing polyimide film by a spin coating method. The solvent was removed on the plate at 60 ° C. Then at 220 ° C in a thermostat
After orientation by heat treatment for 5 minutes, it was taken out and cooled at room temperature to fix the orientation of the liquid crystalline polyester, and an optically anisotropic element was obtained as a film on a glass substrate. In the obtained optically anisotropic element film, the twist hybrid orientation is fixed, the film thickness is 1.0 μm, the apparent in-plane retardation is 100 nm, the average tilt angle is 25 degrees, and the twist angle is 3
It was 0 degrees. This optically anisotropic element and 80 μm-thick negative C-oriented triacetyl cellulose (TAC)
The film and the film were bonded with an adhesive to produce an optical compensation layer (iii). (Preparation of phase type diffraction element layer (ii))

[0138]

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15% by weight of a 10:72:18 (weight ratio) mixture of the above bifunctional low-molecular liquid crystal (2), monofunctional chiral liquid crystal (3) and racemic monofunctional liquid crystal (4), Irgacure 907 (trade name, Ciba
Specialty Chemicals 0.3% by weight, Kayacure DETX (trade name, manufactured by Nippon Kayaku) as a sensitizer
0.03% by weight, and Megafac F as a surfactant
-144D (trade name, manufactured by Dainippon Ink) 0.05% by weight
Γ-butyrolactone solution was prepared. The solution was rubbed with polyethylene terephthalate (P
ET) onto a substrate (trade name: HSL-PET, manufactured by Teijin) by spin coating, and removing the solvent at 60 ° C.
Then, heat treatment is performed at 100 ° C. for 3 minutes in a thermostatic oven, and after orientation in the smectic A phase, the temperature is lowered at a rate of 5 ° C./min to 60 ° C., which is the temperature for orientation in the chiral smectic C phase, and further heat treatment at 60 ° C. for 3 minutes. did. After being taken out at room temperature and purged with nitrogen, the liquid crystal material is quickly polymerized with an irradiation energy of 800 mJ / cm ² using an ultraviolet irradiation device having a high-pressure mercury lamp of 120 W / cm, thereby fixing the orientation of the liquid crystal material, and PET. The phase type diffraction element layer (ii) was obtained as a film on the substrate. The obtained phase type diffraction element layer (ii) is
It was fixed with a chiral smectic C phase having a helical structure, and had a uniform film thickness (1.2 μm). The helical axis was inclined about 18 degrees in the film thickness direction with respect to the substrate surface. The direction of the helical axis in the film plane did not coincide with the rubbing direction, and was shifted about 13 degrees counterclockwise.

Observation with a polarizing microscope and observation with an electron microscope of the cross section of the film revealed that the helical pitch of the helical structure formed in the phase type diffraction element layer (ii) was about 0.9 μm. (Production and evaluation of liquid crystal display device) Optical compensation layer (iii) 2
A TN-type liquid crystal display device having the same mode as that of the liquid crystal display device shown in FIG. 6 described above was manufactured by using the single crystal, one phase-type diffraction element layer (ii) and the test panel, and the gradation characteristics were evaluated. However, compared to the liquid crystal display device of Comparative Example 1, it was found that a display having excellent viewing angle characteristics and substantially no inversion region was obtained.

[0141]

Embodiment 4 (Preparation of Optical Compensation Layer (iv))

[0142]

Embedded image

A liquid crystal substance of the formula (5) was synthesized with reference to JP-A-10-333139. In the formula (5), the numbers next to the parentheses indicate the molar composition ratio. That is, in the liquid crystal substance of the formula (5), three types of side chains are ester-bonded to the nucleus of the hexavalent discotic liquid crystal molecule at a ratio of 2.88: 3.0: 0.12. The liquid crystal material of the formula (5) contains, as a chiral unit, an optically active menthyloxybenzoic acid unit prepared from (1R, 2S, 5R)-(-)-menthol. This material exhibited a chiral discotic nematic phase at temperatures above 65 ° C. 15% by weight of this liquid crystal material, 0.3% by weight of Irgacure 907 (trade name, manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and Kayacure DETX (trade name, manufactured by Nippon Kayaku) as a sensitizer. 03% by weight, and Megafac F-144D (trade name, manufactured by Dainippon Ink) as a surfactant.
A triethylene glycol dimethyl ether solution containing 05% by weight was prepared. The solution was applied by a spin coating method on a TAC substrate having a rubbing treatment and having an orientation film of polyvinyl alcohol having a thickness of 80 μm and having a negative C orientation, and the solvent was removed at 60 ° C. Then 130 ° C
And then taken out at room temperature. After quickly purging with nitrogen, 600 mJ / cm ² was applied using an ultraviolet irradiation apparatus having a 120 W / cm high pressure mercury lamp.
The orientation of the liquid crystal material was fixed by photopolymerization with the irradiation energy. The film on the TAC substrate thus obtained had a fixed twist hybrid orientation, a film thickness of 2.0 μm, an apparent in-plane retardation of 45 nm, an average tilt angle of 55 ° and a twist angle of 45 °. Accordingly, an optical compensation layer (iv) composed of an optically anisotropic element having a twisted hybrid orientation fixed and an optically anisotropic element having a negative C orientation as a substrate was obtained. (Production and evaluation of liquid crystal display device) Two optical compensation layers (iv),
Using one phase-type diffraction element layer (ii) manufactured in Example 3 and the test panel, a TN-type liquid crystal display device having the same mode as the liquid crystal display device shown in FIG. As a result, it was found that, compared to the liquid crystal display device of Comparative Example 1, a display having excellent viewing angle characteristics and no inversion region was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of hybrid alignment of a liquid crystal material having optically positive uniaxiality in an optically anisotropic element included in an optical compensation layer used in a liquid crystal display device of the present invention. In (a) of the figure, the paper surface is z in the xyz coordinate system.
The direction perpendicular to the x-plane and the paper surface is the y-axis direction. Arrows in the figure represent liquid crystal directors. The director of a nematic liquid crystal or discotic liquid crystal does not originally have a distinction between the front and the rear, but is distinguished by a head and a tail to indicate the correspondence with FIG. (B) schematically shows the change in the direction of the projection vector of the director onto the xy plane in the film thickness direction.

FIG. 2 shows an example of hybrid alignment of a liquid crystal substance having an optically negative uniaxial property in an optically anisotropic element included in an optical compensation layer used in the liquid crystal display device of the present invention, in the same manner as in FIG. It is a schematic diagram.

FIG. 3 shows an example of a twisted hybrid alignment of an optically positive uniaxial liquid crystal material in an optically anisotropic element included in an optical compensation layer used in the liquid crystal display device of the present invention in the same manner as in FIG. FIG.

FIG. 4 shows an example of a twisted hybrid alignment of a liquid crystal material having an optically negative uniaxial property in an optically anisotropic element included in an optical compensation layer used in the liquid crystal display device of the present invention in the same manner as in FIG. FIG.

FIG. 5 is a schematic diagram illustrating an example of an embodiment of a liquid crystal display device of the present invention.

FIG. 6 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 7 is a schematic diagram showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 8 is a schematic diagram showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 9 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 10 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 11 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 12 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 13 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 14 is a schematic view showing another example of the mode of the liquid crystal display device of the present invention.

FIG. 15 is a schematic diagram illustrating an embodiment of a liquid crystal display device in Comparative Example 1.

[Explanation of symbols]

 1A to 1G; phase type diffraction element layer 2A to 2C; polarizing layer 3A to 3D; optical compensation layer 4; liquid crystal cell 5; adhesive layer or adhesive layer 6;

Continuing on the front page (72) Inventor Ryo Nishimura 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Nippon Oil & Oil Co., Ltd. (72) Inventor Shinichi Komatsu 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Nippon Oil Central Research Laboratory Co., Ltd. F term (reference) 2H049 AA03 AA25 BA02 BA06 BA42 BB03 BC02 BC22 2H091 FA08X FA08Z FA11X FA11Z FA19X FB02 FC02 FC04 FD06 GA06 GA11 GA13 HA07 HA09 HA10 HA12 LA19

Claims (7)

[Claims] 1. A liquid crystal display device comprising at least a liquid crystal cell in which a liquid crystal phase is formed between two opposing transparent electrode substrates, and a polarizing layer disposed outside both surfaces of the liquid crystal cell. A liquid crystal display device comprising: one optical compensation layer; and at least one phase-type diffraction element layer outside the surface of the liquid crystal cell. 2. The optical compensation layer includes a liquid crystal material exhibiting optically positive uniaxiality, and at least comprises an optically anisotropic element in which a hybrid orientation of the liquid crystal material is fixed. The liquid crystal display device according to claim 1. 3. The optical compensation layer includes a liquid crystal material exhibiting optically negative uniaxiality, and at least comprises an optically anisotropic element in which the hybrid orientation of the liquid crystal material is fixed. The liquid crystal display device according to claim 1. 4. The optical compensation layer includes a liquid crystal material exhibiting optically positive uniaxiality, and at least comprises an optically anisotropic element in which a twisted hybrid alignment of the liquid crystal material is fixed. The liquid crystal display device according to claim 1. 5. The optical compensation layer comprises a liquid crystal material exhibiting optically negative uniaxiality, and at least comprises an optically anisotropic element in which the twisted hybrid orientation of the liquid crystal material is fixed. The liquid crystal display device according to claim 1. 6. The method according to claim 1, wherein the phase type diffraction element layer is at least composed of a liquid crystalline film.
6. The liquid crystal display device according to any one of 5. 7. The phase-type diffraction element layer comprises at least a film in which the orientation of a smectic liquid crystal phase having a helical structure is fixed.
6. The liquid crystal display device according to any one of items 5 to 5.