JPH09329785A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element which is improved in the visual angle characteristic of display colors and is capable of exactly displaying white and halftones without depending upon visual angles. SOLUTION: The optically anisotropic element of the liquid crystal display element having a polarizing element, the optically anisotropic element and a liquid crystal cell consists of a transparent high-polymer film coated with a plane orientable layer and a layer contg. a disk-shaped compd. The difference between the wavelength dispersion value of the refractive index anisotropy of the optically anisotropic element and the wavelength dispersion value of the refractive index anisotropy of liquid crystals is specified to <=20%. Further, the optically anisotropic element has no directions where a retardation value is zero. Namely, the direction where the optical axis does not exist and the absolute value of the retardation value is minimal is neither the normal direction of the film nor the surface direction.

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 an improved contrast change depending on a viewing angle and a tint change in white and halftone.

[0002]

2. Description of the Related Art A CRT, which is a mainstream display device of OA equipment such as a Japanese word processor and a desktop personal computer.
Has been converted to a liquid crystal display element having great advantages such as thin and light weight and low power consumption. Many of the liquid crystal display elements (hereinafter referred to as LCDs) that are currently widely used use twisted nematic liquid crystals. Display methods using such a liquid crystal can be roughly classified into two methods, a birefringence mode and an optical rotation mode.

An LCD using the birefringence mode is twisted at an angle of 90 ° or more in the arrangement of liquid crystal molecules and has a sharp electro-optical characteristic, so that a simple matrix can be used without an active element (thin film transistor or diode). A large capacity display can be obtained by time-sharing driving even in the shape of an electrode. However, it has a drawback that the response speed is slow (several hundreds of milliseconds), and gradation display is difficult.
It does not exceed the display performance of CDs and MIM-LCDs.

In the TFT-LCD and the MIM-LCD, an optical rotation mode display method (TN type liquid crystal display element) in which the alignment state of liquid crystal molecules is twisted by 90 ° is used. This display method is the most effective method as compared with other LCDs because it has a high response speed (several + milliseconds), can easily obtain a black and white display, and has a high display contrast. However, since the twisted nematic liquid crystal is used, there is a problem in viewing angle characteristics that a display color and a display contrast change depending on a viewing direction due to a principle of a display method.
It does not go beyond the display performance of.

SID '92 Digest p. 798
As has been described, there is proposed a method of compensating the viewing angle characteristic by dividing the pixel and inverting the tilt directions when applying a voltage. According to this method, the viewing angle characteristics relating to the gradation inversion in the vertical direction are improved, but the viewing angle characteristics of the contrast are hardly improved.

JP-A-4-229828 and JP-A-4-4-2
As disclosed in Japanese Patent No. 58923, a method has been proposed in which a viewing angle is increased by disposing a retardation film between a pair of polarizing plates and a TN type liquid crystal cell.

The retardation film proposed in the above patent publication has a retardation of almost zero in the direction perpendicular to the surface of the liquid crystal cell, does not exert any optical action from the front and tilts. When the liquid crystal cell has a retardation, the retardation is manifested in the liquid crystal cell. However, even with these methods, the viewing angle of LCD is still insufficient, and further improvement has been desired.

Further, in JP-A-4-366808 and JP-A-4-366809, a viewing angle is improved by using a liquid crystal cell containing a chiral nematic liquid crystal having an inclined optical axis as a retardation film. It is a layered liquid crystal system, which is expensive and very heavy. Further, in JP-A-4-113301, JP-A-5-80323, and JP-A-5-157913, a retardation film in which a polymer chain, an optical axis or an optical elastic axis is inclined with respect to a liquid crystal cell is used. However, there is a problem that it is difficult to obtain a large-area retardation film at low cost, such as by slicing a uniaxial polycarbonate obliquely. Further, although reference is made to the improvement of the viewing angle of the STN-LCD, no specific effect is shown for the improvement of the viewing angle of the TN-LCD.

Further, Japanese Patent Laid-Open Publication No. 5-215921 proposes a method for optically compensating an LCD by a birefringent plate in which a rod-shaped compound exhibiting liquid crystal property at the time of curing is sandwiched between a pair of substrates subjected to alignment treatment. However, this plan is no different from the so-called double-cell type compensator that has been proposed in the past, and it causes a great increase in cost and is practically unsuitable for mass production. Further, no effect has been shown on improving the omnidirectional viewing angle of a TN type LCD.

Further, in JP-A-3-9326 and JP-A-3-291601, LC is obtained by applying a polymer liquid crystal to a film-like substrate having an alignment film.
Although an optical compensating plate for D is described, it is impossible to orient the molecules obliquely by this method, and therefore it is not possible to expect any improvement in the omnidirectional viewing angle of the TN type LCD.

Further, in EP0576304A1 and Japanese Patent Laid-Open No. 6-75116 by the present inventors, a viewing angle characteristic is improved by using a retardation plate having an optically negative uniaxial property and an optical axis inclined. How to do is described. According to this method, the viewing angle is significantly improved as compared with the conventional one, but it is still impossible to improve the viewing angle to the extent that a CRT alternative is considered.

Therefore, the inventors of the present invention have disclosed in Japanese Patent Laid-Open No. 7-3335.
No. 97, an optically anisotropic element whose optical axis is optically negative and whose optical axis is inclined from the normal direction of the film, and optically negative uniaxial element whose optical axis is in the normal direction of the film With the characteristics of a certain optical anisotropic element, there is no optical axis, and the direction in which the absolute value of the retardation value is the minimum is
It has been found that a viewing angle characteristic of a liquid crystal display device having a TN type liquid crystal is remarkably improved by a retardation film that is neither in the film normal direction nor in the plane direction. In addition, JP-A-8-50
In No. 206, it was found that the viewing angle characteristics were further improved by continuously changing the optical axis in the thickness direction of the optically anisotropic layer.

The retardation film proposed in the above patent publication has significantly improved the visual field characteristics, and the image can be seen from a considerably inclined angle. However, when mounted on a TN type liquid crystal cell, it is white due to the viewing angle with respect to the liquid crystal surface. In addition, the halftone screen color may have a yellowish tint, which causes a change in hue.

[0014]

DISCLOSURE OF THE INVENTION The present invention provides a liquid crystal display device in a TN type crystal cell in which the change in contrast depending on the viewing angle and the change in hue depending on the viewing angle in white and intermediate gradations are improved without lowering the front contrast. Is provided.

[0015]

The above-mentioned objects have been achieved by the following means. (1) In a liquid crystal display element having at least a polarizing element, an optically anisotropic element, and a liquid crystal cell, the optically anisotropic element includes at least one transparent polymer film and at least one layer containing a discotic compound. The difference between the wavelength dispersion value of the refractive index anisotropy of the optical anisotropic element and the wavelength dispersion value of the refractive index anisotropy of the liquid crystal is 20% or less, and the optical anisotropic element is a letter. A liquid crystal display device characterized in that there is no direction in which the retardation value is zero, that is, there is no optical axis, and the direction in which the absolute value of the retardation value is the minimum is neither the film normal direction nor the surface direction.

(2) The optical anisotropic element is characterized by comprising at least one transparent polymer film, an optically negative uniaxial plane-orienting layer, and a layer containing a discotic compound ( The liquid crystal display device according to 1).

(3) The optical properties of the transparent polymer film satisfy the formulas 1 and 2, and the optical properties of the layer containing the discotic compound satisfy the formulas 3 and 4, and the discotic compound. The liquid crystal display element according to (1), characterized in that the angle formed by the disc surface and the film normal direction is continuously changed in the thickness direction of the discotic compound-containing layer. Formula 1 100≤ {(nx1 + ny1) / 2-nz1}
× d1 ≦ 1000 Formula 20 ≦ | (nx1 −ny1) × d1 | ≦ 200 Formula 3 50 ≦ {(n1 + n2) / 2−n3} × d2 ≦
1000 Formula 40 ≤ | (n1-n2) x d2 | ≤ 200 (where nx1 and ny1 are the average values of the in-plane main refractive index of the transparent polymer film, and nz1 is the average value of the main refractive index in the thickness direction). Where d1 represents the sum of the thickness of the transparent polymer film, n1, n2 and n3 represent the average main refractive index of the discotic compound-containing layer, and d2 is the thickness of the discotic compound-containing layer. , And the unit of the above formula is nm.)

(4) The total optical characteristics of the transparent polymer film and the plane-alignment layer satisfy the expressions (5) and (6), and the optical characteristics of the layer containing the discotic compound satisfy the expressions (3) and (4). The liquid crystal according to (2), which is satisfied and the angle formed by the disc surface of the discotic compound and the film normal direction is continuously changed in the thickness direction of the discotic compound-containing layer. Display element. Formula 5 100≤ {(nx1 + ny1) / 2-nz1}
Xd1 + {(nx2 + ny2) / 2-nz2} * d3 +
≦ 1000 Formula 60 ≦ | (nx1 −ny1) × d1 | + | (nx
2−ny2) × d3 | ≦ 200 (where nx2 and ny2 are the average in-plane main refractive indices of the plane-alignment layer, nz2 is the average main refractive index in the thickness direction, and d3 is the plane orientation). Represents the thickness of the conductive layer, and the unit of the above formula is nm.)

(5) The liquid crystal display element according to any one of (1) to (4), wherein the thickness of the optically anisotropic element between the polarizing element and the liquid crystal cell is 200 μm or less.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The operation of the present invention will be described below by taking a TN type liquid crystal display element as an example with reference to the drawings. FIGS. 1, 2 and 3 show the polarization state of light propagating in the liquid crystal cell when a voltage equal to or higher than the threshold voltage is applied to the liquid crystal cell, and show a bright state when no voltage is applied. Things. FIG. 2 is a diagram illustrating a polarization state of light when the light is vertically incident on the liquid crystal cell. When the natural light L0 is vertically incident on the polarizer A1 having the polarization axis PA, the light transmitted through the polarizer A becomes linearly polarized light L1.

In the figure, LC is a schematic representation of the alignment state of the liquid crystal molecules when a sufficient voltage is applied to the TN type liquid crystal cell by one liquid crystal molecule model. When the molecular long axis of the liquid crystal molecule LC in the liquid crystal cell is parallel to the light path PS, there is no difference in the refractive index on the incident surface (in the plane perpendicular to the light path), and therefore the light propagates in the liquid crystal cell. There is no phase difference between ordinary light and extraordinary light, and the linearly polarized light L1 propagates as it is when it passes through the liquid crystal cell. When the polarization axis PB of the polarizer B is set to be perpendicular to the polarization axis PA of the polarizer A, the light L2 transmitted through the liquid crystal cell is
Cannot pass through the polarizing plate and is in a dark state.

FIG. 3 is a diagram showing a polarization state of light when the light obliquely enters the liquid crystal cell. Natural light L of incident light
When 0 is obliquely incident, the polarized light L transmitted through the polarizer A
1 becomes almost linearly polarized light. (In the actual case, it becomes elliptically polarized light due to the characteristics of the polarizing plate). In this case, a difference in the refractive index occurs on the incident surface of the liquid crystal cell due to the refractive index anisotropy of the liquid crystal,
The light L2 transmitted through the liquid crystal cell becomes elliptically polarized light, and the polarizer B
Will be transmitted. Such transmission of light at oblique incidence causes an undesired reduction in contrast.

The present invention is intended to prevent such a decrease in contrast due to oblique incidence, improve viewing angle characteristics, and at the same time improve front contrast. FIG.
FIG. 1 shows an example of the configuration according to the present invention. The optical anisotropic element RF of the present invention is arranged between the liquid crystal cell CE and the polarizer B. The optically anisotropic element RF functions like a birefringent body that polarizes more as the angle of incidence of light on the optical axis increases. Light L obliquely enters the liquid crystal display element having such a structure as in the case of FIG. 3 and is transmitted through the liquid crystal cell CE.
Although 2 is elliptically polarized light, the elliptically polarized light is modulated to the original linearly polarized light by the phase delaying action when transmitting through the laminated body RF of the optically anisotropic element, and the same transmittance is obtained even in various oblique incidences. A good liquid crystal display device having no viewing angle dependency was realized.

It is presumed as follows that the viewing angle characteristic of the liquid crystal display device was significantly improved by the present invention. Most TN-LCDs adopt a normally white mode. In this mode, as the viewing angle is increased, the transmittance of light from the black display section is significantly increased, resulting in a sharp decrease in contrast. The black display is a state when a voltage is applied. At this time, the TN cell can be regarded as a positive uniaxial optical anisotropic body whose optical axis is slightly inclined from the normal direction to the cell surface. This slight tilt of the optical axis not only causes birefringence even in front of the cell, but also causes significant asymmetry of the viewing angle in the vertical direction of the cell, that is, the main viewing angle direction, which significantly impairs the viewing angle in either one or both directions. become.

When the optical axis of the liquid crystal cell is tilted from the direction normal to the surface of the liquid crystal cell, it is expected that the optical anisotropic body having the optical axis in the normal direction will be insufficiently compensated. Further, if the liquid crystal cell can be regarded as a positive optical anisotropic body, it must be a negative uniaxial optical anisotropic body to compensate for it. For these reasons, the viewing angle characteristics are improved by the discotic compound-containing layer which is a negative uniaxial optically anisotropic body in which the optical axis of the present invention is tilted from the normal direction. (FIG. 4)

However, regarding the optical anisotropy of the TN type liquid crystal cell as a positive uniaxial property is merely an approximation, and in reality, the liquid crystal cell is not a simple positive optical anisotropic body but a twisted orientation. , The tilt angle is also changing. Therefore, it is naturally limited to compensate with a negative uniaxial optical anisotropic body having an inclined optical axis. As a result of diligent studies, the present inventors have further improved the viewing angle and opened up the possibility of CRT substitution, in the direction in which the retardation value becomes zero, that is, the optical axis does not exist, and It has been found that it can be realized by using an optical anisotropic element in which the direction in which the absolute value of the retardation value becomes the minimum is neither the film normal direction nor the surface direction. As a specific method, a layer containing a discotic compound having a negative uniaxial property and an inclined optical axis is provided on a transparent polymer film having a negative uniaxial property and an optical axis in the film normal direction. As a result, it was possible to realize optical characteristics in which the optical axis was not present and the minimum Re value was neither in the film normal direction nor in the plane direction. Further, since the tilt angle of the liquid crystal cell continuously changes in the thickness direction, the black angle of the TN liquid crystal cell is changed by continuously changing the angle formed by the disc surface of the discotic compound and the film normal direction. Compensation at the time of display was completed completely, and the viewing angle characteristics seen in contrast were greatly improved.

On the other hand, in the conventional TN type LCD, there is a problem that the halftone characteristics change depending on the viewing angle, which occurs in full color display. These are called gradation inversion, white spots, and black shadows depending on the phenomenon that occurs. Due to the optical characteristics of the optical anisotropic element of the present invention in which the optical axis does not exist and the minimum value of Re is neither in the film normal direction nor in the surface direction, gradation reversal, whiteout, and blackout shadow depending on the viewing angle can be significantly reduced. It was There is also a problem that the white display is colored yellow depending on the viewing angle, but the difference between the wavelength dispersion value of the refractive index anisotropy of the optical anisotropic element and the wavelength dispersion value of the refractive index anisotropy of the liquid crystal is 25 A significant improvement could be realized by setting it to be less than or equal to%.

The elliptically polarizing plate and the liquid crystal display device of the present invention have improved viewing angle characteristics of display color without lowering the front contrast, and can accurately display white and intermediate gradations regardless of the viewing angle. Thinks like. Compensation must be performed for light of various wavelengths, such as in color displays. If the light of various wavelengths in the visible range is not sufficiently compensated, the liquid crystal display element causes a tint change depending on the viewing angle. Especially when the black display is perfectly compensated, the white display causes a slight lack of compensation.
A slight retardation occurs depending on the viewing angle,
By adjusting the wavelength dispersion to the liquid crystal cell, it is possible to suppress the occurrence of retardation due to the viewing angle. Also,
By setting the total thickness of the optically anisotropic element to 200 μm or less, it was possible to suppress the increase in absorption caused by the increase in the optical path length depending on the viewing angle.

The refractive index anisotropy of the liquid crystal used in the TN type liquid crystal cell is generally large on the short wavelength side and small on the long wavelength side (referred to as positive wavelength dispersion). In addition, the refractive index anisotropy of the discotic compound generally exhibits a larger positive wavelength dispersion. On the other hand, triacetyl cellulose, which is usually used as a protective film for a polarizing element, exhibits negative wavelength dispersion. The present inventors have passed an optical anisotropic element between a polarizing element and a liquid crystal cell, that is, at least one transparent polymer film, at least one plane-alignment layer, and at least one layer containing a discotic compound. It was found that by compensating the wavelength dispersion of the anisotropy of refractive index caused by that with the wavelength dispersion of the anisotropy of the refractive index of the liquid crystal cell, it compensates for light of all wavelengths in the visible range. The change in color can be greatly reduced.

In the present invention, the wavelength dispersion αLC of the refractive index anisotropy of the liquid crystal cell is represented by the ratio of the retardation between light having a wavelength of 450 nm and light having a wavelength of 550 nm, Re (λ = 450 nm) /
It is defined by Re (λ = 550 nm). Similarly, in the case of a laminate, the wavelength dispersion αRF of the refractive index anisotropy of the optically anisotropic element is
It is defined by the wavelength dispersion value of the refractive index anisotropy caused by passing through all layers.

The wavelength dispersion of the refractive index anisotropy of the optically anisotropic element is matched with the wavelength dispersion of the refractive index anisotropy of the TN type liquid crystal, that is, 0.75 ≦ αRF / αLC ≦ 1.25 so that the transparency is high. By designing the refractive index anisotropy of the molecular film, the layer containing the discotic compound, and the plane-orienting layer, almost eliminating the tint change depending on the viewing angle of the liquid crystal display device equipped with the optically anisotropic element of the present invention. I was able to.

The above description has been made by taking the normally white mode as an example, but the same applies to the normally black mode. In the normally black mode, black display is when no voltage is applied. Also in this case, the optical axis does not exist, and the direction in which the absolute value of the retardation value is the minimum is neither the film normal direction nor the surface direction. It was able to be greatly reduced.

Next, embodiments of the present invention will be described in detail. In the present invention, there is a negative uniaxiality as a specific method for realizing an optical anisotropic element in which the optical axis does not exist and the direction in which the absolute value of the retardation value is the minimum is neither the film normal direction nor the surface direction. In addition, a method of using a discotic compound-containing layer as an optical anisotropic body having an inclined optical axis and using a transparent polymer film as an optical anisotropic body having negative uniaxiality and having an optical axis in the film normal direction is preferable. Further, in order to adjust the wavelength dispersion to the liquid crystal cell, it is more preferable to provide a plane-alignment layer made of a material having a negative uniaxiality and having a wavelength dispersion suitable as an optical anisotropic body having an optical axis in the film normal direction. .

In addition, since the angle formed by the disc surface of the discotic compound and the film normal direction continuously changes in the thickness direction, the discotic compound-containing layer alone does not have an optical axis, and the retardation value It is further preferable that the direction in which the absolute value is the minimum is neither the film normal direction nor the surface direction.

Negative uniaxiality has a relationship of n1 <n2 = n3, where n1, n2, and n3 are the refractive indices of the optically anisotropic substance in the triaxial directions in the decreasing order. Therefore, it has a characteristic that the refractive index in the optical axis direction is the smallest. However, the values of n2 and n3 do not have to be exactly equal, and it is sufficient if they are almost equal. Specifically, if | n2-n3 | / | n2-n1 | ≦ 0.2, there is no practical problem.

The tilt angle of the optical axis of the optically anisotropic body having negative uniaxiality and the tilted optical axis is tilted from the film normal direction by 5 ° to 85 ° as a condition for significantly improving the viewing angle characteristics. Is preferable, 10 ° to 40 ° is more preferable, and 20 ° to 35 ° is most preferable. Further, when the thickness of the sheet is D and Δn = n2-n1 is defined, it is preferable that the condition of 50 ≦ Δn · D ≦ 400 (nm) is satisfied.

The material used for the transparent polymer film of the present invention is not particularly limited, but various polymer materials, liquid crystals, blends or cross-linked products thereof are preferably used. Of these, a film made of a polymer material is preferable. Such a polymer film has a light transmittance of 8
It is preferably 0% or more. Therefore, materials with a small intrinsic birefringence such as Zeonex (Nippon Zeon), ARTON (Nippon Synthetic Rubber), Fujitac (Fuji Photo Film), etc., such as polycarbonate, polyarylate, polysulfone, polyethersulfone, etc. A material having a large intrinsic birefringence can also be suitably used.

In the present invention, the transparent polymer film may or may not also serve as a protective film for the polarizing element, but in consideration of the optical properties of the protective film, the optical properties of the transparent polymer film, It is necessary to design the optical characteristics of the plane orientation layer described below. Further, between the polarizing element and the liquid crystal cell is the above-mentioned optical anisotropic element, while the outer protective film may be the same optical anisotropic element, but with a trade name such as Zeonex, ARTON, Fujitac, etc., which has a small birefringence. It is preferable to use a commercially available film.

Next, the discotic compound of the present invention refers to, for example, C, Research report of Destrade et al., Mol. Cr
yst. 71, page 111 (1981), benzene derivatives and B.I. Kohne et al., Angew. Chem. Volume 96, p. 70 (1984
Year) and the cyclohexane derivative described in J. M. L
ehn et al., J. Chem. Commun. ,
Pp. 1794 (1985), J. Research report by Zhang et al. Am. Chem. Soc. Volume 116, 2655
Examples include azacrown-based and phenylacetylene-based macrocycles described on page (1994), which are generally used as the mother nucleus of the molecular center, and linear alkyl groups, alkoxy groups, substituted benzoyloxy groups, etc. Is a structure in which the straight chain is radially substituted, and exhibits liquid crystallinity,
It includes what is generally called a discotic liquid crystal. However, the molecule is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. Further, in the present invention, the term "formed from a discotic compound" does not mean that the final product is the compound, and, for example, the low-molecular-weight discotic liquid crystal is heated,
Those having a group which reacts with light or the like and consequently polymerized or crosslinked by the reaction with heat, light or the like to have a high molecular weight and lose the liquid crystallinity are also included.

The discotic compound in the present invention is a discotic liquid crystal as listed below, or a reaction product of a discotic liquid crystal which no longer exhibits liquid crystallinity due to reaction with other low molecular weight compounds or polymers. As described above, the molecule itself means all compounds having optically negative uniaxiality.

[0041]

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[0042]

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[0043]

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[0044]

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When the discotic compound in the present invention is a discotic liquid crystal, the layer containing them is oriented so as to have an optically negative uniaxial axis and an optical axis inclined from 5 ° to 50 ° from the normal direction of the film. The following processing is required for this. Specifically, on the above-mentioned transparent polymer film, a rubbing-treated organic alignment film or inorganic alignment film is formed, a discotic liquid crystal is applied thereon, and then a liquid crystal phase, more preferably a disconematic phase formation temperature. Is to raise the temperature. As a result, the liquid crystal is obliquely aligned, and remains in the solid state at room temperature while maintaining the alignment by subsequent cooling. Further, the discotic nematic liquid crystal phase forming temperature is unique to the discotic liquid crystal, but can be arbitrarily adjusted by mixing two or more different types. The discotic liquid crystal used in the present invention has a discotic nematic liquid crystal phase-solid phase transition temperature of preferably 50 ° C or higher and 300 ° C or lower, particularly preferably 70 ° C or higher and 150 ° C or lower.

The organic alignment film may be a polyimide film or polystyrene derivative, and the water-soluble film may be a gelatin film or polyvinyl alcohol. By subjecting all of them to rubbing treatment, the discotic liquid crystal can be oriented obliquely.
Of these, the alkyl-modified polyvinyl alcohol is particularly preferable, and the present inventors have discovered that it has an excellent ability to uniformly align the discotic liquid crystal. It is speculated that this is due to the strong interaction between the alkyl chains on the alignment film surface and the alkyl side chains of the discotic liquid crystal. The above alkyl-modified polyvinyl alcohol has an alkyl group at the terminal as listed below, and has a saponification degree of 80%.
As described above, the polymerization degree is preferably 200 or more. Further, polyvinyl alcohol having an alkyl group in a side chain can also be used effectively. As a commercial item, made by Kuraray; MP103, M
P203, R1130, etc. are available.

A polyimide film, which is widely used as a liquid crystal alignment film for LCD, is also preferable as the organic alignment film.
This is a polyamic acid (eg Hitachi Chemical; LQ / L
X series, manufactured by Nissan Kagaku; SE series, etc.) is applied to the surface of the substrate, baked at 100 to 300 ° C. for 0.5 to 1 hour, and then rubbed.

The rubbing treatment is the same method widely used as a liquid crystal alignment treatment process for LCDs, and the surface of the alignment film is made of paper, gauze, felt, rubber,
Alternatively, it is a method of obtaining orientation by rubbing nylon, polyester, rayon fiber or the like in a certain direction. Generally, rubbing is performed by winding a cloth, on which fibers having uniform length and thickness are evenly flocked, wound around a roll and contacting the surface of the alignment film while rotating.

As the vapor deposition material for the inorganic oblique vapor deposition film,
TiO represented by SiO₂, MgF ₂, ZnO₂Etc gold
Examples include metal oxides and fluorides, metals such as Au and Al.
You. If the metal oxide has a high dielectric constant, it is oblique vapor deposition.
It can be used as a substance and is not limited to the above.
There is no. A fixed substrate method and a film for the formation of a vapor deposition film
Both of the continuous vapor deposition type methods can be used, and S is used as the vapor deposition material.
Taking iO as an example, the deposition angle α is about 65-88 °.
The optical axis of a discotic liquid crystal is the color of vapor-deposited particles.
It is uniformly oriented in a direction approximately orthogonal to the direction of the column.

The above-mentioned alignment film has a function of determining the alignment direction of the discotic liquid crystal molecules coated thereon, but since the alignment property of the discotic liquid crystal depends on the alignment film, its combination is optimized. There is a need. Further, the uniformly aligned discotic liquid crystal molecules are aligned at an angle with the normal line of the film, but the tilt angle does not change much depending on the alignment film and often takes a value specific to the discotic liquid crystal molecules. When two or more discotic liquid crystals are mixed or a compound similar to the discotic liquid crystal is mixed, the tilt angle can be adjusted by the mixing ratio. Therefore, a method of selecting or mixing discotic liquid crystals is more effective for controlling the tilt angle of the oblique alignment.

As another method for orienting the discotic liquid crystal obliquely, magnetic field orientation or electric field orientation can be mentioned. In this case, it is necessary to apply a magnetic field or an electric field at a desired angle while heating the substrate coated with the discotic liquid crystal.

In order to maintain the oblique orientation of the discotic compound thus obtained even under high temperature and high humidity, a polymerizable unsaturated group, an epoxy group, a hydroxyl group and an amino group are previously added to the discotic compound. Groups, functional groups such as carboxyl groups, radical polymerization of polymerizable unsaturated groups by heat or photopolymerization initiator, ring-opening polymerization of epoxy groups by photoacid generator, polyvalent isocyanate, polyvalent It is preferable to crosslink the discotic compound itself by a crosslinking reaction with an epoxy compound. At this time, another compound having the same functional group may be contained.

The plane-alignment layer in the invention is preferably provided by being dissolved or dispersed in water or an organic solvent and applied on the protective film of the polarizing element or the above-mentioned transparent polymer film. The material used is not particularly limited, but various polymeric materials having a positive intrinsic birefringence and wavelength dispersion of birefringence close to that of a liquid crystal cell, a discotic compound, a rod-shaped compound, a liquid crystal, or a blend thereof. Are preferably used. A rigid structure is preferable for the plane orientation in the coating and drying step.
Further, in the liquid crystal, a cholesteric polymer liquid crystal or a polymer dispersion of a nematic liquid crystal, which easily forms a homogeneous monodomain, is more preferable. As specific materials, in addition to the materials described above for the transparent polymer film, discotic compound and alignment film material, rod-shaped liquid crystals such as azoxy, azomethine, substituted biphenyl and phenylcyclohexane compounds are preferably used. Further, the plane orientation layer of the present invention can also serve as the above-mentioned orientation film.

In the present invention, when the above-mentioned optical anisotropic element is mounted between the polarizing element and the liquid crystal cell, the discotic compound-containing layer may be disposed near the liquid crystal cell or may be disposed on the polarizing element side. However, in the present invention, they may be arranged in either direction. However, in order to maximize the compensation ability, it is preferable to dispose the discotic compound-containing layer closer to the liquid crystal cell and to dispose the transparent polymer film or the plane alignment layer closer to the polarizing element. When the elliptically polarizing plate of the present invention is used in a TN type liquid crystal cell, it is necessary that the optical anisotropic element of the protective film of the elliptically polarizing plate faces the TN type liquid crystal cell side.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. Example 1 (Preparation of transparent polymer film) 7 parts by weight of triphenyl phosphate and 3.5 parts by weight of biphenyldiphenyl phosphate were added to 100 parts by weight of triacetyl cellulose manufactured by Daicel Corporation, and the weight ratio of methylene chloride to methanol was 9. A dope, which was dissolved in a mixed solvent of 1 to a solid content concentration of 15% by weight, was cast on a stainless steel band so that the dry film thickness was 80 μm, and stripped off.
It was dried with hot air at 0 ° C. to 120 ° C. to produce triacetyl cellulose film A1. The main refractive index in the plane is nx, n
When y, the refractive index in the thickness direction is nz, and the thickness is d, the triacetylcellulose film A has | nx-ny | xd
= 3 nm, {(nx + ny) / 2-nz} * d = 20n
m, which was almost negative uniaxial, and the optical axis was almost in the film normal direction. Also, the wavelength dispersion value α of the refractive index anisotropy
TAC = 0.58 (the ratio of Re at 450 nm to Re at 550 nm).

(Coating of Discotic Compound) A gelatin layer (0.5 μm) is coated on one side of the above-mentioned triacetyl cellulose film A1 and a grain size of 0.1 μm is coated on the opposite side.
Diacetyl cellulose layer (0.2 μm) containing silica
Was applied. Next, the following alignment layer coating liquid was applied on the coated gelatin layer with a slide coater at 25 cc / m ² , and
It was dried with warm air of 0 ° C. for 60 seconds and further with warm air of 90 ° C. for 150 seconds.

Alignment Layer Coating Liquid Compound (1) 10 g Water 371 g Methanol 119 g Crosslinking Agent (Glutaraldehyde) 0.5 g

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A rubbing roll having a diameter of 150 mm, a film conveying speed of 30 m / min, a lapping angle of 6 degrees,
The rubbing treatment was performed under the rubbing conditions of a rubbing roll rotation speed of 600 rpm and a film substrate conveying tension of 90 gf / cm.

On the alignment film, 1.8 g of the above-mentioned discotic liquid crystal TE-8 (8) (m = 4), 0.2 g of trimethylolpropane EO-modified triacrylate (# 360 manufactured by Shin Osaka Chemical Co., Ltd.), and cellulose Suacetate butyrate (CAB551-0.2 manufactured by Eastman Chemical) 0.
04 g, a photopolymerization initiator (Irga Cure 907 manufactured by Ciba-Geigy), a sensitizer (Kayacure manufactured by Nippon Kayaku)
A coating solution prepared by dissolving 0.02 g of DETX) in 3.43 g of methyl ethyl ketone was applied with a wire bar (5.2c).
c / m ² ), and after sticking to a metal frame, putting the coating material in a temperature atmosphere of 130 ° C. and heating for 3 minutes to orient the discotic liquid crystals, 120 W / c at 130 ° C.
1 with a high pressure mercury lamp of 600 m and an illuminance of 600 mW / cm ² .
After irradiating the coated surface with UV for 2 seconds, the temperature was returned to room temperature to prepare a triacetyl cellulose film A2 coated with a discotic compound-containing layer. The thickness of the discotic compound-containing layer was about 2.6 μm. This discotic compound-containing layer has a refractive index n1 of n1, n2, and n3 in the order of decreasing main refractive index.
It had a relationship of <n2 = n3 and was negative uniaxial. Further, the optical axis was inclined by 30 ° from the film normal direction. {(N1 + n2) / 2-n3} × d2 = 110n
m, .vertline. (n1 -n2) .times.d2 .vertline. = 55 nm. Further, the wavelength dispersion value αDLC of the refractive index anisotropy = 1.15 (4
Ratio of Re at 50 nm to Re at 550 nm).

(Production of Polarizing Element) After stretching a polyvinyl alcohol film, iodine was adsorbed to produce a polarizing element.

(Preparation of Elliptical Polarizing Plate) The surface of the triacetyl cellulose film A1 was saponified, and two polarizing plates were laminated on both sides of the above polarizing element with an adhesive to prepare a polarizing plate. On the back surface of the triacetyl cellulose film A2 coated with the layer, that is, on the surface coated with the diacetyl cellulose layer (0.2 μm) containing silica, a release paper with an acrylic pressure-sensitive adhesive is attached, and the above polarizing plate is attached to form an ellipse. A polarizing plate A3 was produced. An optical anisotropic element laminate of the elliptically polarizing plate thus obtained, which comprises the triacetyl cellulose film A1 and the triacetyl cellulose film A2 containing the discotic compound-containing layer,
The absolute value of the retardation was minimum in the direction tilted by 20 ° from the film normal direction without the optical axis, and the minimum value was 17 nm. The wavelength dispersion value αRF of the refractive index anisotropy of the optically anisotropic element laminate was αRF = 0.99.

(Production of Liquid Crystal Display Element) The product of the difference in refractive index between the extraordinary light and the ordinary light of the liquid crystal and the gap size of the liquid crystal cell is 47.
Two elliptically polarizing plates A3 were attached to a TN type liquid crystal cell having a twist angle of 90 degrees at 0 nm so as to sandwich the liquid crystal display element, and thereby a liquid crystal display element A was produced. The optical anisotropic element is arranged on the liquid crystal cell side. The wavelength dispersion value αLC of the anisotropy of the liquid crystal cell was αLC = 1.06, and the difference from αRF was 7%.

Example 2 (Preparation of transparent polymer film) 10 parts by weight of triphenyl phosphate and 5 parts by weight of biphenyldiphenyl phosphate were mixed with 100 parts by weight of triacetyl cellulose manufactured by Daicel Corp. to give a weight ratio of methylene chloride and methanol. 80 μm in the same manner as in Example 1 except that the solid content was dissolved in a mixed solvent of 9: 1 at a solid concentration of 15% by weight.
An m 3 triacetyl cellulose film B1 was prepared.
The triacetyl cellulose film B1 is | nx -ny
| * D = 6 nm, {(nx + ny) / 2-nz} * d =
The thickness was 40 nm, which was almost negative uniaxial, and the optical axis was almost in the film normal direction. The wavelength dispersion value αTAC of the refractive index anisotropy was 0.58.

(Application of Discotic Compound) In the same manner as in Example 1, a discotic compound-containing layer was coated on the triacetyl cellulose film B1. This discotic compound-containing layer had a relationship of n1 <n2 = n3 and was negative uniaxial. Further, the optical axis was inclined by 30 ° from the film normal direction. {(N1 + n2) / 2-n3} × d2 = 1
10 nm and | (n1-n2) * d2 | = 55 nm. Further, the wavelength dispersion value αDLC of the refractive index anisotropy = 1.1
It was 5.

(Production of Polarizing Element) A polarizing element was produced in the same manner as in Example 1.

(Preparation of Elliptical Polarizing Plate) Only one sheet of triacetyl cellulose film B, the surface of which was saponified, was attached to one side of a polarizing element with an adhesive, and then a discotic compound-containing layer was formed on the opposite side. A release paper with an acrylic pressure-sensitive adhesive was attached to the back surface of the applied triacetyl cellulose film B, that is, the surface on which the diacetyl cellulose layer containing silica was applied, and the above-mentioned polarizing plate was adhered to produce an elliptically polarizing plate B. Of the elliptically polarizing plate thus obtained,
The optically anisotropic element composed of the triacetyl cellulose film A1 and the discotic compound-containing layer has no optical axis, and the absolute value of the retardation in the direction inclined by 20 ° from the film normal direction is the minimum, and the minimum value is 12 nm. there were. Further, the wavelength dispersion value αRF of the refractive index anisotropy of the optically anisotropic element is
It was 1.00.

(Production of Liquid Crystal Display Element) In the same manner as in Example 1, two pieces of the elliptically polarizing plate B were attached so as to sandwich the liquid crystal display element, and a liquid crystal display element B was produced. The wavelength dispersion value of the refractive index anisotropy of the liquid crystal cell αLC = 1.06, and αR
The difference from F was 6%.

Comparative Example 1 (Preparation of Transparent Polymer Film) A triacetyl cellulose film B1 was prepared in the same manner as in Example 1. Also,
A triacetyl cellulose film C1 cast to have a thickness of 100 μm was produced. The triacetyl cellulose film C1 has | nx-ny | xd = 10 nm,
{(Nx + ny) / 2-nz} × d = 50 nm,
It was almost negative uniaxial, and the optical axis was almost in the film normal direction. Further, the wavelength dispersion value αTAC of the refractive index anisotropy =
It was 0.58.

(Application of Discotic Compound) Example 1 except that the thickness of the discotic compound-containing layer was set to about 2.0 μm.
A discotic compound-containing layer was applied onto the triacetyl cellulose film C1 in the same manner as in. This discotic compound-containing layer had a relationship of n1 <n2 = n3 and was negative uniaxial. Also, the optical axis is 35 from the film normal direction.
It was inclined. {(N1 + n2) / 2-n3} × d2
= 70 nm and | (n1 -n2) * d2 | = 35 nm. Further, the wavelength dispersion value αDLC = 1.
It was 15.

(Production of Polarizing Element) A polarizing element was produced in the same manner as in Example 2.

(Preparation of Elliptical Polarizing Plate) After the surface of the triacetyl cellulose film B1 was saponified with an aqueous KOH solution, two polarizing plates were laminated on both sides of the above polarizing element with an adhesive to prepare a polarizing plate. A release paper with an acrylic pressure-sensitive adhesive is attached to the back surface of the triacetyl cellulose film C1 coated with the compound-like compound-containing layer, that is, the surface coated with the diacetyl cellulose layer containing silica, and the above polarizing plate, and the elliptically polarized light. A plate C was produced. The optical anisotropic element laminate of the elliptically polarizing plate C thus obtained, which is composed of the triacetyl cellulose films B1 and C1 and the discotic compound-containing layer, has no optical axis and is inclined by 20 ° from the film normal direction. The absolute value of the retardation in the direction was the minimum, and the minimum value was 17 nm. Further, the wavelength dispersion value αRF of the refractive index anisotropy of the optically anisotropic element laminate is 0.8
It was one.

(Production of Liquid Crystal Display Element) In the same manner as in Example 1, two pieces of the elliptically polarizing plate C were attached so as to sandwich the liquid crystal display element, and a liquid crystal display element C was produced. The wavelength dispersion value of the refractive index anisotropy of the liquid crystal cell αLC = 1.06, and αR
The difference from F was 24%.

Example 3 (Preparation of transparent polymer film) In the same manner as in Example 1,
A triacetyl cellulose film A1 was produced. The triacetyl cellulose film A1 has | nx-ny | x
d = 3 nm, {(nx + ny) / 2-nz} * d = 20
nm, almost uniaxial, and the optical axis was almost in the film normal direction. The wavelength dispersion value αTAC of the refractive index anisotropy was 0.58.

(Coating of plane-orienting layer) In the same manner as in (Coating of discotic compound) in Example 1, a gelatin layer (0.5 μm) was formed on one side of the above triacetylcellulose film A1.
m) was applied, and a diacetyl cellulose layer (0.2 μm) containing silica having a particle size of 0.1 μm was applied on the opposite surface. Next, on the coated gelatin layer, Nippon Synthetic Chemical Co., Ltd.
A 2 wt% methyl ethyl ketone solution of the soluble polyester TP-220 manufactured by Co., Ltd. was applied with a slide coater at 30 cc / m 2 and heated with hot air at 60 ° C. for 60 seconds and then with hot air at 90 ° C. for 1 second.
It was dried for 50 seconds. This plane-oriented layer is | nx-ny
│ × d = 2 nm, {(nx + ny) / 2-nz} × d =
The thickness was 40 nm, which was almost negative uniaxial, and the optical axis was almost in the film normal direction. The wavelength dispersion value αPET of the refractive index anisotropy was 1.22.

(Coating of Discotic Compound) On the above-mentioned plane-orienting layer, an alignment film was coated in the same manner as in Example 1, and then a discotic compound-containing layer of about 2.0 μm was coated. This discotic compound-containing layer had a relationship of n1 <n2 = n3 and was negative uniaxial. The optical axis was inclined by 35 ° from the film normal direction. {(N1 + n2) / 2-n3
} × d2 = 70 nm, │ (n1-n2) × d2│ = 3
It was 5 nm. Also, the wavelength dispersion value αD of the refractive index anisotropy
LC = 1.15.

(Production of Polarizing Element) A polarizing element was produced in the same manner as in Example 2.

(Preparation of Elliptical Polarizing Plate) After the surface of the triacetyl cellulose film A1 was saponified with an aqueous KOH solution, two sheets were attached on both sides of the above polarizing element with an adhesive to prepare a polarizing plate. The back surface of the triacetyl cellulose film A1 coated with the orientation layer and the discotic compound-containing layer, that is, the surface coated with the diacetyl cellulose layer containing silica is bonded with a release paper with an acrylic pressure-sensitive adhesive, and the above polarizing plate is used. Lamination was carried out to produce an elliptically polarizing plate D. The thus obtained elliptically polarizing plate D has an optical anisotropic element comprising two triacetyl cellulose films A1, a plane orientation layer and a discotic compound-containing layer, which has no optical axis.
The absolute value of retardation in the direction inclined by 20 ° from the film normal direction was the minimum, and the minimum value was 15 nm. The wavelength dispersion value αRF of the refractive index anisotropy of the optically anisotropic element laminate was 1.02.

(Production of Liquid Crystal Display Element) In the same manner as in Example 1, two pieces of the elliptically polarizing plate D were attached so as to sandwich the liquid crystal display element, and a liquid crystal display element D was produced. The wavelength dispersion value of the refractive index anisotropy of the liquid crystal cell αLC = 1.06, and αR
The difference from F was 4%.

Example 4 (Preparation of transparent polymer film) In the same manner as in Example 1,
A triacetyl cellulose film A1 was produced. The triacetyl cellulose film A1 is | nx-ny | xd
= 6 nm, {(nx + ny) / 2-nz} * d = 20 nm
And the optical axis was almost in the direction of the film normal. Also, the wavelength dispersion value αT of the refractive index anisotropy
AC = 0.58.

(Application of Planar Orientation Layer) In the same manner as in Example 3, a gelatin layer (0.5 μm) was applied on one side of the above-mentioned triacetylcellulose film B1, and the particle size was applied on the opposite side. A diacetyl cellulose layer (0.2 μm) containing 0.1 μm of silica was applied. Next, a 2 wt% methyl ethyl ketone solution of soluble polyester K-1089 manufactured by Toray Industries, Inc. was applied on the applied gelatin layer with a slide coater at 50 cc / m2, and heated with hot air at 60 ° C for 90 seconds and then at 90 ° C. It was dried by air for 210 seconds. This plane-orientation layer has | nx −ny | × d = 2 nm, {(nx + ny) /
2-nz} × d = 60 nm, which was almost negative uniaxial, and the optical axis was almost in the film normal direction. The wavelength dispersion value αPET of the refractive index anisotropy was 1.18.

(Coating of Discotic Compound) On the above-mentioned plane-oriented layer, an alignment film was applied in the same manner as in Example 1, and then a discotic compound-containing layer of about 2.0 μm was applied. This discotic compound-containing layer had a relationship of n1 <n2 = n3 and was negative uniaxial. The optical axis was inclined by 35 ° from the film normal direction. {(N1 + n2) / 2-n3
} × d2 = 70 nm, │ (n1-n2) × d2│ = 3
It was 5 nm. Also, the wavelength dispersion value αD of the refractive index anisotropy
LC = 1.15.

(Production of Polarizing Element) A polarizing element was produced in the same manner as in Example 2.

(Preparation of Elliptical Polarizing Plate) Only one sheet of triacetyl cellulose film B, the surface of which was saponified, was attached to one side of a polarizing element with an adhesive, and then a discotic compound-containing layer was formed on the opposite side. The back surface of the applied triacetyl cellulose film B, that is, the surface on which the diacetyl cellulose layer containing silica was applied, was bonded with a release paper with an acrylic pressure-sensitive adhesive and bonded with the above polarizing plate to prepare an elliptical polarizing plate E. . The thus-obtained elliptically polarizing plate of the optically anisotropic element composed of the triacetyl cellulose film B1, the plane orientation layer and the discotic compound-containing layer had no optical axis and was tilted at 20 ° from the film normal direction. The absolute value of retardation in the direction is the minimum, and the minimum value is 12n
m. The average value of the wavelength dispersion of the refractive index anisotropy of the laminate was αRF = 1.07.

(Production of Liquid Crystal Display Element) In the same manner as in Example 1, two pieces of the elliptically polarizing plate E were attached so that the liquid crystal display element was sandwiched therebetween to produce a liquid crystal display element E. The wavelength dispersion value of the refractive index anisotropy of the liquid crystal cell αLC = 1.06, and αR
The difference from F was 3%.

When a driving voltage is applied to the liquid crystal display elements A to E so as to have a white to intermediate tone and the hue changes depending on the viewing angle, A, B, D and E of the examples are compared with C of the comparative example. Almost no coloring was observed, and good viewing angle characteristics were exhibited.

[0087]

According to the present invention, the TN type liquid crystal display element, the TFT type liquid crystal display element, the MIM type liquid crystal display element, the TF.
It is possible to provide a liquid crystal display device of high quality display, which has improved contrast and deterioration of color tone depending on the viewing angle of the D-type liquid crystal display device and has excellent visibility. Needless to say, the present invention can be applied to other active matrix liquid crystal display elements using three-terminal elements and two-terminal elements to obtain excellent effects.

[Brief description of drawings]

FIG. 1 is a diagram illustrating one example of a configuration of a liquid crystal display element of the present invention.

FIG. 2 is a diagram illustrating a configuration of a conventional TN-type liquid crystal display device and a diagram illustrating a light transmission state when light is vertically incident on a display surface.

FIG. 3 is a diagram illustrating a configuration of a conventional TN type liquid crystal display element and a light transmission state when light obliquely enters a display surface.

FIG. 4 is a schematic diagram showing a principle that a viewing angle characteristic is improved by a negative uniaxial optical anisotropic body having an optical axis inclined from a normal direction.

[Explanation of symbols]

 L0 -------- Incident light A, B -------- Polarizer PA, PB -------- Polarization axis L1 -------- Light PS -------- Direction of light CE ------------- TN-type liquid crystal cell L2 -------- Light emitted from TN-type liquid crystal cell LC- Liquid crystal molecule RF ------- Optical anisotropic element

Claims (5)

[Claims] 1. At least a polarizing element and an optically anisotropic element,
And a liquid crystal display device having a liquid crystal cell, wherein the optical anisotropic element comprises at least one transparent polymer film and at least one layer containing a discotic compound, and the optical anisotropic element has an anisotropic refractive index. The difference between the wavelength dispersion value of the liquid crystallinity and the wavelength dispersion value of the refractive index anisotropy of the liquid crystal is 20% or less, and the optical anisotropic element has no direction in which the retardation value becomes zero, that is, A liquid crystal display device characterized by having no axis and the direction in which the absolute value of the retardation value is the minimum is neither the film normal direction nor the surface direction. 2. The optically anisotropic element comprises at least one transparent polymer film, an optically negative uniaxial plane-orienting layer, and a layer containing a discotic compound. 1. The liquid crystal display element according to 1. 3. The optical properties of the transparent polymer film satisfy the formulas 1 and 2, and the optical properties of the layer containing the discotic compound satisfy the formulas 3 and 4, and the discotic compound The liquid crystal display element according to claim 1, wherein an angle formed by the disc surface and the film normal direction is continuously changed in the thickness direction of the discotic compound-containing layer. Formula 1 100≤ {(nx1 + ny1) / 2-nz1}
× d1 ≦ 1000 Formula 20 ≦ | (nx1 −ny1) × d1 | ≦ 200 Formula 3 50 ≦ {(n1 + n2) / 2−n3} × d2 ≦
1000 Formula 4 0 ≦ | (n1 −n2) × d2 | ≦ 200 (where nx1 and ny1 are the average values of the in-plane main refractive index of the transparent polymer film, and nz1 is the average value of the main refractive index in the thickness direction). Where d1 represents the sum of the thicknesses of the transparent polymer film, n1, n2 and n3 represent the average main refractive index of the discotic compound-containing layer, and d2 is the thickness of the discotic compound-containing layer. , And the unit of the above formula is nm.) 4. The total optical properties of the transparent polymer film and the plane-alignment layer satisfy formulas 5 and 6, and the optical properties of the layer containing the discotic compound satisfy formulas 3 and 4. Sushi,
The liquid crystal display device according to claim 2, wherein the angle formed by the disc surface of the discotic compound and the film normal direction is continuously changed in the thickness direction of the discotic compound-containing layer. Formula 5 100≤ {(nx1 + ny1) / 2-nz1}
Xd1 + {(nx2 + ny2) / 2-nz2} * d3 +
≦ 1000 Formula 60 ≦ | (nx1 −ny1) × d1 | + | (nx
2−ny2) × d3 | ≦ 200 (where nx2 and ny2 are the average in-plane main refractive indices of the plane-alignment layer, nz2 is the average main refractive index in the thickness direction, and d3 is the plane orientation). Represents the thickness of the conductive layer, and the unit of the above formula is nm.) 5. The liquid crystal display element according to claim 1, wherein the thickness of the optically anisotropic element between the polarizing element and the liquid crystal cell is 200 μm or less.