JPH10153802A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize a contrast, visual field angle characteristics and response characteristics by disposing a phase difference plate having positive refractive index anisotropy and a phase difference plate having negative refractive index anisotropy adjacently toward a liquid crystal panel including a liquid crystal layer having positive or negative refractive index anisotropy, successively from the side of the liquid crystal panel. SOLUTION: The phase difference plate having the positive refractive index anisotropy and the phase difference plate having the negative refractive index anisotropy are disposed adjacently toward the liquid crystal panel including the liquid crystal layer having the positive or negative refractive index anisotropy, successively from the side of the liquid crystal panel. An optically biaxial phase difference compensation film is otherwise disposed adjacently toward the liquid crystal panel. The retardation value of the liquid crystal layer is set at 80 to 400nm. For example, the phase difference compensation films 33A, 33B are disposed above and below the liquid crystal panel of the liquid crystal display 30. A polarizer 34A is formed on the lower side of the phase difference compensation film 33A and an analyzer 34B on the upper side of the phase difference compensation film 33B, respectively in prescribed bearings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a liquid crystal display, and more particularly to a so-called VA in which liquid crystal having a positive or negative dielectric anisotropy is aligned in a direction substantially perpendicular to a panel surface of the liquid crystal display. The present invention relates to a liquid crystal display device operating in a mode.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used as display devices for various information processing apparatuses such as computers. Since the liquid crystal display device is small and has low power consumption, the liquid crystal display device is often used particularly for an information processing device for portable use. However, application to a fixed type information processing device such as a desktop type is under study.

In a conventional liquid crystal display device, a so-called TN (twisted nematic) mode in which p-type liquid crystals having a positive dielectric anisotropy are horizontally aligned between substrates of a liquid crystal display device facing each other. Has been mainly used. The TN mode liquid crystal display device is characterized in that the alignment direction of liquid crystal molecules adjacent to one substrate is twisted by 90 ° with respect to the alignment direction of liquid crystal molecules adjacent to the other substrate.

In such a TN mode liquid crystal display device, various liquid crystals have already been developed and an inexpensive manufacturing technique has been established. However, it is difficult to realize a high contrast, and as a result, the TN mode liquid crystal display device is generally used. In the display device,
The liquid crystal panel is configured to display white in a non-driving state in which no electric field is applied to the liquid crystal molecules, and black in a driving state in which an electric field is applied to the liquid crystal molecules. This is because, in the case of the conventional TN mode liquid crystal display device, the liquid crystal molecules are aligned parallel to the surface of the liquid crystal panel in the non-driving state, and the alignment direction of the liquid crystal molecules changes substantially perpendicular to the liquid crystal panel in the driving state. In the driving state, the liquid crystal molecules adjacent to the liquid crystal panel maintain the horizontal alignment even in the driving state, and the light passes through the liquid crystal panel to some extent even in the driving state due to the birefringence formed by the liquid crystal molecules having the horizontal alignment. It is. If the TN mode liquid crystal display device attempts to display the background in black,
As a result of birefringence generated by the liquid crystal molecules near the substrate, the background black does not actually become completely black, causing a problem that light leaks or is colored. Under such circumstances, the conventional TN mode liquid crystal display device uses white as a background color.

On the other hand, a liquid crystal layer having a positive or negative dielectric anisotropy is sealed between a pair of substrates constituting a liquid crystal panel so as to be vertically aligned or vertically inclined.
In the A-mode liquid crystal display device, since the liquid crystal molecules have an orientation substantially perpendicular to the substrate surface in the non-driving state, light passes through the liquid crystal layer without substantially changing its polarization plane, and as a result, By arranging the polarizing plates on the upper and lower sides, almost complete black display is possible in the non-driving state. In other words, such a VA mode liquid crystal display device
Very high contrast, which is impossible with a TN mode liquid crystal display device, can be easily realized. In a driving state in which a driving electric field is applied to the liquid crystal molecules, the liquid crystal molecules are aligned in the liquid crystal panel in parallel with the panel surface, and rotate the plane of polarization of the incident light beam. However, in the driving state of the VA mode liquid crystal display device, the horizontally aligned liquid crystal molecules exhibit a 90 ° twist between one substrate and the other substrate. By doing so, the plane of polarization of light passing through the liquid crystal layer is rotated.

[0006] The VA mode itself has been known for a long time,
For example, regarding the physical properties of a liquid crystal exhibiting a negative dielectric anisotropy,
D. de Rossi and others have already reported (J. Appl. Phy
s. 49 (3), March 1978).

[0007]

However, conventionally, V
The A-mode liquid crystal display device is considered to be inferior in display quality such as response time, viewing angle characteristics, voltage holding ratio, etc., even though the contrast ratio is superior to that of the TN mode liquid crystal display device. R & D efforts were not much done. In particular, it was believed that it was difficult to realize an active matrix type liquid crystal panel using thin film transistors (TFTs).

On the other hand, in the VA mode liquid crystal display device, a contrast comparable to that of a conventional CRT can be obtained.
Such a desktop type liquid crystal display device is required to have a particularly large viewing angle in addition to a large area and a high response speed. Accordingly, it is a general object of the present invention to provide a new and useful VA mode liquid crystal display device which has solved the above-mentioned problems.

A more specific object of the present invention is to provide a VA mode liquid crystal display device using a liquid crystal having a positive or negative dielectric anisotropy, which is particularly optimized with respect to viewing angle and contrast. .

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by providing a first liquid crystal layer sandwiching a liquid crystal layer.
And a second substrate; a first polarizer disposed on a side of the first substrate opposite to a side in contact with the liquid crystal layer; and a second substrate with a side in contact with the liquid crystal layer. Is a liquid crystal display device comprising a second polarizing plate disposed on the opposite side,
Positive refraction is applied to at least one of a first gap between the first substrate and the first polarizing plate and a second gap between the second substrate and the second polarizing plate. A first retardation plate having a refractive index anisotropy, and a second retardation plate having a negative refractive index, wherein the second retardation plate is located at the first position with respect to the liquid crystal layer. According to a liquid crystal display device, wherein the liquid crystal layer is disposed outside the retardation plate, or as described in claim 2, the liquid crystal layer is formed of a liquid crystal having a positive dielectric anisotropy. 3. The liquid crystal display according to claim 2, wherein the liquid crystal layer is made of a liquid crystal having a negative dielectric anisotropy. A first or second substrate for sandwiching a liquid crystal layer by a display device or as set forth in claim 4; Of, a first polarizing plate disposed on the side opposite to the side in contact with the liquid crystal layer, of the second substrate,
In a liquid crystal display device comprising: a second polarizing plate disposed on a side opposite to a side in contact with the liquid crystal layer, a first gap between the first substrate and the first polarizing plate; A liquid crystal display device characterized in that an optical biaxial retardation plate is disposed in at least one of the second gaps between the second substrate and the second polarizing plate; or According to a fifth aspect of the present invention, the liquid crystal layer is made of a liquid crystal having a positive dielectric anisotropy. The liquid crystal layer,
The liquid crystal display device according to claim 4, wherein the liquid crystal display device comprises a liquid crystal having a negative dielectric anisotropy, or the first and second substrates which are parallel to each other; First electrode means formed on a first main surface of the first substrate facing the second substrate; second main surface of the second substrate facing the first substrate A second molecular means formed thereon; a first molecular alignment film covering the first electrode means on the first main surface of the first substrate; A liquid crystal comprising: a second molecular alignment film covering the second electrode means on a second main surface; and a liquid crystal layer made of liquid crystal molecules sealed between the first and second substrates. In the display device, the liquid crystal molecules have a long axis of the liquid crystal molecules aligned substantially perpendicular to at least the one main surface of the substrate. The liquid crystal layer, 80 nm or more, 40
The liquid crystal according to claim 7, wherein the liquid crystal molecules have a positive dielectric anisotropy by a liquid crystal display device having a retardation of 0 nm or less or as described in claim 8. According to a display device or as described in claim 9, the first and second substrates form a liquid crystal panel together with the liquid crystal layer interposed therebetween, and the liquid crystal display device further comprises a first absorption layer. A first polarizing plate having an axis, and a second polarizing plate having a second absorption axis, respectively, on the first side and the second opposite side of the liquid crystal panel, the first absorption axis and the second absorption axis. The first and second polarizing plates include a twist center that divides a twist angle in the liquid crystal layer into two equal parts. About 45 ° to axis
The liquid crystal display device according to claim 7 or 8, wherein the liquid crystal display device is disposed so as to form an angle.
0, the liquid crystal display further includes a first gap between the first substrate and the first polarizer and a second gap between the second substrate and the second polarizer. In at least one, a first retardation plate having a positive refractive index anisotropy, a second retardation plate having a negative refractive index anisotropy, the second retardation plate, The liquid crystal display device according to claim 9, wherein the first retardation plate is disposed on a side farther from the liquid crystal panel than the first retardation plate. The phase difference plate is provided so that an optical axis is parallel to an absorption axis of a polarization plate adjacent to the first phase difference plate among the first and second polarization plates. The liquid crystal display device according to claim 10, or as described in claim 12, the first phase. The plate is provided so that an optical axis is orthogonal to an absorption axis of a polarizing plate adjacent to the first retardation plate among the first and second polarizing plates. The liquid crystal display device according to claim 10, or as described in claim 13, wherein the first retardation plate has a thickness of 120 n.
The liquid crystal display device according to any one of claims 10 to 12, wherein the first liquid crystal device has a retardation of m or less.
Wherein the second retardation plate is made of a resin having a norbornene structure in the main chain, or the second retardation plate is as described in claim 15. 15. The liquid crystal according to claim 10, wherein an optical axis is disposed so as to be substantially orthogonal to at least one of the first and second main surfaces. The second retardation plate has a retardation of not more than twice the retardation of the liquid crystal layer by a display device or as described in claim 16, wherein the second retardation plate has a retardation of not more than twice the retardation of the liquid crystal layer. The liquid crystal display device according to claim 1, or as described in claim 17, further comprising a first gap between the first substrate and the first polarizer and the second substrate. The second polarizing plate Second at least one of the gap between, the liquid crystal display device according to claim 9, characterized in that is disposed a phase plate in optical biaxial, or claim 1
As described in 8, the optical biaxial retardation plate includes:
A slow axis included in a plane parallel to the first or second principal surface, wherein the slow axis is the optical biaxial phase difference of the first and second polarizing plates; 20. The optical biaxial retarder according to claim 17, wherein the optical biaxial retarder extends parallel to an absorption axis of a polarizing plate adjacent to the plate. Has a slow axis included in a plane parallel to the first or second principal surface, and the slow axis is the optically biaxial property of the first and second polarizing plates. The liquid crystal display device according to claim 17, which is orthogonal to an absorption axis of a polarizing plate adjacent to the retardation plate, or as described in claim 20, wherein the optically biaxial retardation plate is , Having an in-plane retardation of 120 nm or less, according to any one of claims 17 to 19, 22. The optical biaxial phase difference plate according to claim 21, wherein the retardation plate is twice as large as the retardation of the liquid crystal layer in a direction orthogonal to the first or second main surface. The liquid crystal display device according to any one of claims 17 to 21, wherein the liquid crystal display device further has the following retardation:
A first and a second optically uniaxial retardation plate in a first gap between the first substrate and the first polarizer and in a second gap between the second substrate and the second polarizer, respectively. The liquid crystal display device according to claim 9, wherein the first and second optically uniaxial retardation plates each comprise: 23. The liquid crystal display device according to claim 22, wherein the first and second polarizing plates are arranged such that a slow axis is parallel to an absorption axis of an adjacent polarizing plate. Alternatively, as described in claim 24, each of the first and second optically uniaxial retardation plates has an absorption axis of an adjacent one of the first and second polarizing plates. 23. The liquid crystal display according to claim 22, wherein the liquid crystal display is disposed such that a slow axis is orthogonal to the liquid crystal display. 26. The device according to claim 24, wherein the first and second optically uniaxial retardation plates have an in-plane retardation of 300 nm or less. The first and second optically uniaxial retardation plates have a norbornene structure in the main chain thereof. 28. The liquid crystal display device according to claim 25, wherein the first device is made of a resin.
And the second substrate forms a liquid crystal panel together with the liquid crystal layer interposed therebetween, and the liquid crystal display further includes a first liquid crystal panel.
And a second polarizing plate having a second absorption axis on the first side and the second opposite side of the liquid crystal panel, respectively. And the second absorption axis are orthogonal to each other, and the liquid crystal display device further comprises a first retardation plate having a first slow axis and a second retardation plate.
A second retardation plate having a slow axis between the liquid crystal panel and the second polarizing plate, wherein the first retardation plate is more than the second retardation plate in the liquid crystal panel. And the direction of the first slow axis is substantially perpendicular to the direction of the second absorption axis of the second polarizing plate. The problem is solved by the liquid crystal display device according to claim 7.

Hereinafter, the principle of the present invention will be described. FIG.
1 shows a basic configuration of a liquid crystal display device according to the present invention. Referring to FIG. 1, a liquid crystal display device 10 includes a liquid crystal panel including a pair of glass substrates 11A and 11B opposed to each other and a liquid crystal layer 12 sealed therebetween. A first polarizing plate (polarizer) 13A having an absorption axis in the direction indicated by arrow 13a is provided, and a second polarizing plate (analyzer) 13B having an absorption axis in the direction indicated by arrow 3b is provided above. You.

The liquid crystal forming the liquid crystal layer 12 is a liquid crystal having a positive or negative dielectric anisotropy.
In a non-driving state of the liquid crystal panel where no electric field is applied between B and B, the liquid crystal molecules 12a near the lower substrate 11A
To be oriented substantially perpendicular to. Similarly, the liquid crystal molecules 12b near the upper substrate 11B are oriented substantially perpendicular to the substrate 11B. In other words, the liquid crystal display device 10 has a so-called V
A liquid crystal display device that operates in the A mode is configured.

In the configuration example shown in FIG. 1, the lower substrate 11A has a first alignment film (not shown) rubbed in a direction offset by about 22.5 ° counterclockwise from its longitudinal direction.
Is carried on the upper main surface, and the director indicating the alignment direction of the liquid crystal molecules points to the direction inclined at an angle of about 89 ° above the rubbing direction of the first alignment film for the liquid crystal molecules 12a. Similarly, the lower substrate 11B carries on its lower principal surface a second alignment film (not shown) rubbed in a direction offset clockwise by about 22.5 ° from its longitudinal direction, and the lower substrate 11B carries liquid crystal molecules. The director indicating the orientation direction is
The liquid crystal molecules 12b point in a direction inclined at an angle of about 89 ° downward from the rubbing direction of the second alignment film. That is, in the liquid crystal layer 12, the liquid crystal molecules form a twist angle of 45 ° between the upper and lower substrates 11A and 11B. However, as shown in FIG.
When a liquid crystal panel is formed from 11B, the substrates 11A, 11
B is combined so that the rubbing directions face each other at an angle of 45 °.

A polarizer 13A having an absorption axis 13a is provided below the liquid crystal panel composed of the substrates 11A and 11B.
Is arranged to polarize light incident from below in a direction orthogonal to the absorption axis 13a. Similarly, an analyzer 13B having an absorption axis 13b is disposed above the liquid crystal panel, and polarizes light passing through the liquid crystal panel in a direction orthogonal to the absorption axis 13b. Therefore, when the polarizer 13A and the analyzer 13B are arranged so that the absorption axes 13a and 13b are orthogonal to each other, if the light polarized by the polarizer 13A passes through the liquid crystal panel as it is without any change in the polarization plane, the light is analyzed by the analyzer. 13B, and a black display is obtained.

A transparent electrode (not shown) is formed on the outside of the substrate 13A and on the inside of each of the alignment films on the substrate 13B.
The liquid crystal molecules in the liquid crystal layer 12 are the liquid crystal molecules 12a or 1
As shown in 2b, the light is oriented substantially perpendicular to the substrate surface, and as a result, the polarization state of light passing through the liquid crystal panel hardly changes. That is, the liquid crystal display device 10 realizes an ideal black display in the non-driving state. On the other hand, in the driving state, the liquid crystal molecules tilt substantially parallel to the substrate surface, and the light passing through the liquid crystal panel changes the polarization state by the tilted liquid crystal molecules. In other words, in the liquid crystal display device 10, white display is obtained in the driving state.

FIG. 2A shows the contrast ratio of the liquid crystal display device 10 when the angles φ and θ of the absorption axes 13a and 13b of the polarizer 13A and the analyzer 13B are variously changed. However, the angles φ and θ are defined as shown in the plan view of FIG. 2B, and the contrast ratio is a comparison between a non-drive state (drive voltage of 0 V) and a state in which a drive voltage of 5 V is applied. . In the example of FIG. 2A, Δn = 0.08 as the liquid crystal forming the liquid crystal layer 12.
13, Δε = -4.6 (for example, a liquid crystal product available under the trade name MJ95785 from Merck Japan)
And commercially available polarizing plates 13A and 13B, for example, G1220DU manufactured by Nitto Denko. The thickness of the liquid crystal cell, that is, the thickness d of the liquid crystal layer 12 is 3.5 μm.
Is set to Where Δn = n _e −n ₀ and n
_e, n _o is the extraordinary light and the refractive index of the ordinary ray in the respective liquid crystal. Δε represents dielectric anisotropy.

Referring first to FIG. 2B, this figure shows the twist angle of the liquid crystal molecules in the liquid crystal display device 10, the angle φ formed by the polarizer absorption axis 13a with respect to the center line of the twist, and further with respect to the center line of the twist. The angle θ formed by the analyzer absorption axis 13b is shown. However, FIG.
In the plan view of (B), in order to clearly show the twist angle and its center line, unlike the display of FIG. 1, the liquid crystal display device 10 is configured such that the orientation of the upper substrate 11B is inverted by 180 ° and the lower substrate 11A Are shown in the same direction.

Referring to FIG. 2A, the liquid crystal display 1
The contrast ratio of 0 is maximized when the polarizer 13A and the analyzer 13B are in the orthogonal Nicol state, that is, when the absorption axis 13a and the absorption axis 13b are orthogonal, and particularly φ = 45 °, ie, 0 ° − in FIG. In the state where the angle formed by the polarizer absorption axis 13a with respect to the twist center line corresponding to the straight line connecting 180 ° is 45 °,
It can be seen that the contrast is maximized. In the orthogonal Nicol state, the angle formed by the analyzer absorption axis 13b with respect to the twist center line is 135 °. It is apparent that the same maximum contrast can be obtained even when the angles φ and θ are set to −45 ° and −135 ° in FIG. 2B. In this case, in FIG. 1, the angle between the absorption axis 13a and the twist center line is 135 °, and the angle between the absorption axis 13b and the twist center line is 45 °.

As can be seen from FIG. 2 (A), in the liquid crystal display device 10 according to the present invention, a contrast ratio exceeding 700 can be obtained regardless of the setting of φ and θ, but this result is at most about 100. This shows the superiority of a VA liquid crystal display device over a normal twisted nematic (TN) liquid crystal display device that can only obtain a contrast ratio.

FIGS. 3A to 3D are diagrams for explaining the operating characteristics of the liquid crystal display device 10 of FIG. However, the liquid crystal and the polarizing plate use those described above. 3A is a waveform diagram showing a waveform of a voltage pulse applied to the liquid crystal display device 10, and FIG. 3B is a waveform diagram of FIG.
Liquid crystal display device 10 generated in response to voltage pulse (A)
Are shown by a solid line and a broken line when the chiral material is not added to the liquid crystal layer 12 and when the chiral material is added. However, the results in FIG. 3B are for the case where the thickness d of the liquid crystal cell is set to 3.5 μm, and the twist angle of the liquid crystal molecules is 4 as described above.
5 °. In the illustrated example, the pitch p of the chiral material
Is set so that the ratio d / p to the thickness d of the liquid crystal layer 12 is 0.25. As can be seen from FIG. 3B, when no chiral material was added, the liquid crystal display device 10 exhibited a substantially constant high light transmittance corresponding to the applied voltage pulse. It can be seen that the transmittance of the liquid crystal display device 10 decreases with time when the chiral material is added. In other words, in the VA mode liquid crystal display device 10, the addition of the chiral material generally used in the TN mode liquid crystal display device causes undesirable deterioration of dynamic response characteristics.

FIG. 3C shows that the thickness d of the liquid crystal cell is 3.5.
In the liquid crystal display device 10 of μm, the dynamic transmittance characteristic changes when the twist angle of the liquid crystal molecules is changed in the range of 0 ° to 90 °. As can be seen from FIG. 3C, the dynamic transmittance characteristic accompanying the input pulse in FIG. 3A is hardly affected by the twist angle of the liquid crystal molecules. The control of the twist angle is performed by the substrates 11A and 11A.
This is performed by controlling the rubbing direction of the molecular alignment film on B.

FIG. 3D shows that the thickness d of the liquid crystal cell is 4.5.
The change of the dynamic transmittance characteristic when changing in the range of μm to 2.5 μm is shown. As can be seen from FIG. 3 (D), the transmittance accompanying the input pulse in FIG. 3 (A) decreases as the cell thickness d decreases, but the index indicating the response speed, that is, the transmittance is 0% when on. To the saturation value (transmittance = 1
Time T _ON to reach 90% 00%), also the time T _OFF to transmittance during OFF decreases to 10% saturation value, decreased extent cell thickness is reduced, thus the response speed is increased You can see that In particular, when the cell thickness d is 2.5 μm
When it is set to m or less, the rise and fall of the dynamic transmittance characteristic curve become very steep.

FIGS. 4A and 4B show a configuration in which a liquid crystal having a negative dielectric anisotropy is used for the liquid crystal layer 12 in the liquid crystal display device of FIG. Referring to FIGS. 4A and 4B, an electrode pattern 11a is formed on a glass substrate 11A.
Further, an electrode pattern 11b and a molecular alignment film 11b 'are formed on the glass substrate 11B, and the liquid crystal layer 12 is sandwiched between the molecular alignment films 11a' and 11b '.

4A shows a non-drive state in which no drive voltage is applied between the electrode pattern 11a and the electrode pattern 11b. In this non-drive state, the liquid crystal molecules are molecules. By the action of the alignment films 11a 'and 11b', the alignment is performed substantially perpendicular to the main surface of the substrate. Next, when a driving voltage is applied between the electrode patterns 11a and 11b, as shown in FIG. 4B, the liquid crystal molecules having a negative dielectric anisotropy move in a horizontal direction substantially orthogonal to the driving electric field. Orient.

FIGS. 5A and 5B show a configuration in the case where a liquid crystal having a positive dielectric anisotropy is used for the liquid crystal layer 12 in the VA mode liquid crystal display device of FIG. However, parts corresponding to the parts described above are denoted by the same reference numerals, and description thereof will be omitted. In the configuration of FIGS. 5A and 5B,
The electrode pattern is not formed on the substrate 11B.
Only on A, a pair of adjacent electrode patterns 11a is formed.

In the non-driving state shown in FIG.
The liquid crystal molecules are aligned substantially perpendicular to the main surface of the substrate as in FIG.
In the driving state shown in (B), the semiconductor device is also oriented substantially horizontally along the electric field formed between the pair of electrodes.
FIG. 6 shows a liquid crystal panel 1 including substrates 11A and 11B and a liquid crystal layer 12 sealed between the substrates 11A and 11B in FIG.
1 shows a liquid crystal display device 20 having a configuration in which a phase difference compensation film 14A is inserted.

Referring to FIG. 6, the phase difference compensation film 1
4A is a negative retardation Δn · d ₁ (Δn
_{= N y -n z = n x} -n z; n x, n y, n z is the main axis x of the respective refractive index ellipsoid, y, z-direction of the refractive index, d ₁ is have a thickness) of the retardation film Each is disposed between the liquid crystal panel 11 and the polarizer 13A, and compensates for birefringence of light passing through the liquid crystal panel 11.

FIGS. 7 to 22 show the viewing angle characteristics of the liquid crystal display device 20 provided with such a phase difference compensation film 14A when the magnitude of the retardation R 'of the film 14A is variously changed. However, in FIGS. 7 to 22, circumferential angle values of 0.0 °, 90.0 °, 180.
0 ° and 270.0 ° are the respective azimuth angles, and concentric circles are the viewing angles measured with the panel front direction being 0 °.
Shown in ° intervals. Therefore, in the drawing, the outermost concentric circle is 8
Represents a viewing angle of 0.0 °. Each contour line has a contrast ratio CR of 500.0, 200.0, 100.0, 5
Represents the 0.0 and 10.0 isocontrast lines.

In any of the cases shown in FIGS. 7 to 22, the liquid crystal layer 12 is made of, for example, MJ9 manufactured by Merck Japan.
Using liquid crystal having negative dielectric anisotropy such as 41296,
The viewing angle characteristics are obtained when a driving voltage pulse of 0 V / 5 V is applied to the liquid crystal panel. However, similar viewing angle characteristics can also be obtained when a liquid crystal having a positive dielectric anisotropy is used as the liquid crystal layer 12. Therefore, the results of FIGS. 7 to 22 show the results for the VA mode liquid crystal display device using the liquid crystal having the negative dielectric anisotropy shown in FIGS. The same holds true for a VA mode liquid crystal display device using a liquid crystal having a positive dielectric anisotropy shown in FIGS.

In particular, in FIGS. 7 to 16, the birefringence Δn of the liquid crystal panel 11 is 0.0804, the cell thickness d is 3 μm,
Further, the twist angle of the liquid crystal molecules was 45 ° and the pretilt angle was 89 °. In this case, the retardation Δn · d of the liquid crystal panel 11 is 241 nm. In the example of FIG.
The retardation R ′ is 108 nm, and the ratio R ′ / Δn · d to the retardation value 241 nm of the liquid crystal panel is 0.45, whereas in the example of FIG. 8, the retardation R ′ is 144 nm, and the ratio R ′ / Δn・ D is 0.
It is 6. Further, in the example of FIG. 9, the retardation R ′ is 180 nm and the ratio R ′ / Δn · d is 0.7
5, the retardation R 'is 198n in the example of FIG.
m, the ratio R ′ / Δnd · d is 0.82. In the example of FIG. 11, the retardation R ′ is 216 nm and the ratio R ′ is Δ ′.
In the example of FIG. 12, the retardation R ′ is 234 nm and the ratio R ′ / Δnd is 0.
97, the ratio R ′ / Δn · d is 1.05 in the example of FIG. 13 when the total retardation value R ′ is 252 nm, and in the example of FIG. 14, the ratio R ′ / Δn · d is 270 nm in the retardation R ′. d is 1.12, and in the example of FIG. 15, the retardation R ′ is 288 nm and the ratio R ′ / Δn ·
d is 1.20, and in the example of FIG. 16, the retardation R ′ is 324 nm and the ratio R ′ / Δn · d is 1.3.
It is four.

Referring to FIG. 7 to FIG.
0 is the ratio R ′ / Δ shown in FIG. 11 or FIG.
It can be seen that particularly excellent viewing angle characteristics are exhibited when nd is in the vicinity of 1 (0.97 to 1.05). In other words, FIG.
16 show that the viewing angle characteristic of the liquid crystal display device 20 is significantly improved by disposing the retardation compensation film 14A having a retardation value substantially equal to the retardation value of the liquid crystal panel adjacent to the liquid crystal panel 11. Is shown.

The result described above is also valid when a phase difference compensation film 14B different from the phase difference compensation film 14A is provided above the liquid crystal panel 11 in the configuration of FIG. However, in this case, the retardation R 'is the total value of the retardation compensation films 14A and 14B. FIGS. 17 to 22 show that the total retardation R ′ of the phase difference compensation films 14A and / or 14B substantially matches the retardation Δn · d of the liquid crystal panel 11 in the configuration of FIG.
The viewing angle characteristics when the thickness d of the middle liquid crystal layer 12 is changed are shown. However, in FIGS. 17 to 22, the contour line represented by CR = 10 indicates a viewing angle at which a contrast ratio of 10 is obtained.

As can be seen from FIGS. 17 to 22, the thickness d is 1 μm, and therefore the retardation Δn ·
When d is 82 nm or less, the viewing angle characteristics are clearly deteriorated, and when the thickness d is 5 μm, and thus the retardation Δn · d of the liquid crystal panel 11 is 410 nm or more, the viewing angle characteristics are deteriorated again. From this, it is understood that in the liquid crystal display device 20 of FIG. 6, the retardation of the liquid crystal panel 11 is preferably set to about 80 nm or more, more preferably 82 nm or more, and about 410 nm or less, and more preferably 400 nm or less. A similar conclusion is:
In addition to the liquid crystal display device using the negative dielectric anisotropy liquid crystal shown in FIGS.
The present invention is equally applicable to a liquid crystal display device using a positive dielectric anisotropic liquid crystal shown in FIG.

FIGS. 23 to 28 show the transmittance in the front direction of the liquid crystal display device 20 of FIG. 6 when the thickness d of the liquid crystal layer 12 is variously changed.
= Blue, G = green, R = blue). However, the transmittance was measured while changing the applied voltage from 0 V to 6 V. As can be seen from FIGS. 23 to 26, when the thickness d of the liquid crystal layer is 1 μm or less (Δn · d = 82 nm), the transmittance is very low in any color even when a driving voltage of 6 V is applied. (FIG. 23).

On the other hand, when the thickness d of the liquid crystal layer is increased to 1 μm or more, the transmittance of each of the three primary colors at the time of driving the liquid crystal display device is greatly increased. In particular, as shown in FIGS. When the thickness d of the liquid crystal layer 12 is set to 4 to 5 μm, by setting the magnitude of the driving voltage pulse to about 4 V, substantially the same transmittance is realized for each of the R, G, and B colors. .

On the other hand, by further increasing the thickness of the liquid crystal layer d,
When the thickness is set to 6 μm or more as shown in FIG. 28, the driving voltage at which substantially the same transmittance is obtained for each of the colors R, G, and B is slightly lower than 3 V. The drive voltage range in which the transmittances for the G and B colors are substantially equal is narrower than in FIG. 26 or FIG. In other words, in the configuration of FIG. 28, there is a problem that the white display is colored by a slight change in the drive voltage. However, in a liquid crystal display device that is actually mass-produced, it is difficult to precisely control the driving voltage.

Accordingly, in the liquid crystal display of FIG. 6, the thickness d of the liquid crystal layer 12 is preferably 1 μm or more and 6 μm or less. Accordingly, the retardation of the liquid crystal layer 12 is preferably about 80 nm or more and about 400 nm or less. Similar conclusions are obtained not only for the VA mode liquid crystal display device using the negative dielectric anisotropy liquid crystal shown in FIGS. 4A and 4B, but also for FIGS. 5A and 5B. The same applies to a VA mode liquid crystal display using a positive dielectric anisotropy liquid crystal.

FIGS. 29 to 33 show color changes observed when the polar angle is changed from + 80 ° to −80 ° in the liquid crystal display device of FIG. 6 for each azimuth angle. 29 to 33 show the observed color change as CIE (1
931) is a diagram plotted in a standard color system. FIG. 29-
33, the thick solid line indicates the case where the azimuth is 0 °, the thin solid line indicates the case where the azimuth is 45 °, and the broken line indicates the case where the azimuth is 90 °.

First, referring to FIG. 29, when the thickness d of the liquid crystal layer 12 is 1 μm, and thus the retardation Δn · d of the liquid crystal panel 11 is 82 nm, even if either the polar angle or the azimuth angle changes, The observed color change is slight.
However, as shown in FIG. 30, the thickness d of the liquid crystal layer 12 is 3
In the case of μm (Δnd · 246 nm), the color change is slightly large. However, in the case of FIG. 30, the azimuth dependence of the color change is not yet observed.

On the other hand, the thickness d of the liquid crystal layer 12 is 4 μm.
In the case of FIG. 31 in which (Δn · d = 328 nm), the color change generated by the liquid crystal display device 20 is further increased, and when the azimuth is 90 ° and when the azimuth is 0 ° or 45 °. , A different color change is observed. Furthermore, when the thickness d of the liquid crystal layer 12 is set to 5 μm (Δn · d = 410 nm) as shown in FIG. 32, or as shown in FIG. 33, the thickness d is set to 6 μm (Δnd · =
492 nm), the observed color change is very large.

FIGS. 29 to 33 show that when the VA mode liquid crystal display device is applied to a full color liquid crystal display device requiring a wide viewing angle, the retardation Δn · d of the liquid crystal layer 12 is about 300 nm or less. For example, it is shown that it is preferable to set the wavelength to about 280 nm, which is the middle between FIGS. Similar conclusions are obtained not only for the VA mode liquid crystal display device using the negative dielectric anisotropy liquid crystal shown in FIGS. 4A and 4B, but also for FIGS. 5A and 5B. The same applies to a VA mode liquid crystal display using a positive dielectric anisotropy liquid crystal.

Further, the inventor of the present invention has shown that in the liquid crystal display device 20 shown in FIG. Twelve samples were examined by setting the thickness d to 3 μm.
34 to 36 show the twist angles of 0 °, 90 °, and 90 °, respectively.
9 shows viewing angle characteristics when the angle is set to 180 °. As can be seen from FIGS. 34 to 36, a substantial change in the viewing angle characteristics due to the twist angle is hardly observed. A similar relationship is shown in FIG.
V using a negative dielectric anisotropic liquid crystal shown in (A) and (B).
As for the A-mode liquid crystal display device, FIG.
The same holds true for the VA mode liquid crystal display device using the positive dielectric anisotropic liquid crystal shown in FIG.

In the above experiment described with reference to FIG. 6 and subsequent figures, the liquid crystal layer 12 constituting the liquid crystal display device 20 is provided with a chiral material generally used in a normal TN mode liquid crystal display device. No additions were made. FIG.
Is a liquid crystal MX94129 manufactured by Merck Japan Ltd. as a liquid crystal.
6 (Δn = 0.082, Δε = −4.6), and the transmittance of the liquid crystal display device 20 shown in FIG. 6 in the black display mode when the G1220DU of Nitto Denko is used as the polarizing plate is 90 °. In the case where the polar angle is changed from 0 ° to 80 ° at the azimuth angle shown in FIG. However, the thickness d of the liquid crystal layer 12 was 3.5 μm. In this case, the retardation Δn · d formed by the liquid crystal layer 12 is 287 nm.

As can be seen from FIG. 37, the transmittance in the black display mode can be minimized by setting the retardation value R 'of the phase difference compensating film 14A to around 287 nm which is equal to the retardation of the liquid crystal layer 12. . A similar relationship applies to the VA mode liquid crystal display device using the negative dielectric anisotropy liquid crystal shown in FIGS. The same holds true for a VA mode liquid crystal display device using a dielectric anisotropic liquid crystal.

The inventor of the present invention further studied the effect of the addition of a chiral material on the viewing angle characteristics in a VA mode liquid crystal display device. In a VA mode liquid crystal display device,
In the non-drive state where no drive voltage is applied, the liquid crystal molecules
As shown in (A), since they are substantially vertically oriented,
Although the effect of the chiral material on the viewing angle characteristics does not appear remarkably, it is considered that some effect appears due to the regulation of the chiral pitch by the chiral material in the driving state in which the liquid crystal molecules are horizontally aligned as shown in FIG. FIG. 38 (B)
In the state (1), the liquid crystal molecules are twisted by the chiral material in the thickness direction of the liquid crystal layer at a uniform twist angle determined by the chiral pitch p of the chiral material and the thickness d of the liquid crystal layer.
On the other hand, when no chiral material is added, FIG.
As shown in (A), even though the orientation of the liquid crystal molecules in the non-driving state is the same as in FIG. 38 (A) in which the chiral material is added, in the driving state, there is no regulation of the chiral pitch by the chiral material. The twist of liquid crystal molecules becomes non-uniform. That is, as shown in FIG. 39 (B), although the twist of the liquid crystal molecules is generated in the vicinity of the molecular alignment films supported on the upper and lower substrates, a region in the center in the thickness direction of the liquid crystal layer 12 (FIG. 39). In region C) in (B), twist of liquid crystal molecules hardly occurs.

FIG. 40 shows a case where the thickness d of the liquid crystal layer 12 is 3 μm and the twist angle of the liquid crystal molecules is 90 ° in the liquid crystal display device 20 of FIG. The viewing angle characteristics when the ratio is 0.25 are shown. The viewing angle characteristics in FIG. 40 are compared with FIG. 35 showing the viewing angle characteristics in a case where the chiral material is not added in the liquid crystal display device having the same configuration, and it can be seen that the region where the contrast ratio is 10 or more is reduced. That is, in the VA mode liquid crystal display device, it is concluded that it is preferable not to add a chiral material also from the viewpoint of viewing angle characteristics.

FIGS. 41 and 42 show the R, R and R in the liquid crystal panel front direction when the thickness d of the liquid crystal layer 12 is 3 μm and the twist angle of the liquid crystal molecules is 90 °.
The luminance characteristics of each of the G and B colors are shown. 41 shows the case where the chiral material was added, and FIG. 41 shows the case where the chiral material was not added. Obviously, the addition of the chiral material lowers the brightness of the liquid crystal display. This is because, when the chiral material is added, a uniform twist of the liquid crystal molecules occurs as shown in FIG. 38 (B) in the driving state, whereas when the chiral material is not added, FIG. 39 (B) As shown in (1), in the driving state of the liquid crystal display device, a region C where liquid crystal molecules are not twisted is formed. In this region C, it is considered that the light beam changes the polarization plane efficiently. That is, it is concluded that it is preferable not to add a chiral material also in the VA mode liquid crystal display device from the viewpoint of luminance characteristics. Similar conclusions apply to the VA mode liquid crystal display using the negative dielectric anisotropy liquid crystal shown in FIGS. 4A and 4B, and to the positive liquid crystal display shown in FIGS. 5A and 5B. The same applies to a VA mode liquid crystal display device using a dielectric anisotropic liquid crystal.

The inventor of the present invention further examined the change in the viewing angle characteristics by changing the pretilt angle of the liquid crystal molecules in the liquid crystal display device 20 shown in FIG. The results are shown in FIGS.
FIG. FIG. 43 shows that the pretilt angle is 89.99.
44 shows the case where the pretilt angle is set to 85 °, FIG. 45 shows the case where the pretilt angle is set to 80 °, and FIG. 46 shows the case where the pretilt angle is set to 75 °. . FIG. 47 shows the viewing angle characteristics of a standard TN mode liquid crystal display device.

Referring to FIGS. 43 to 47, in the case of FIG. 43 in which the pretilt angle is substantially 90 °, the widest viewing angle is realized, whereas as the pretilt angle decreases, the viewing angle decreases. When the pretilt angle shown in FIG. 46 is 75 °, the viewing angle becomes equal to the viewing angle of the standard TN mode liquid crystal display device shown in FIG. For this reason, in the VA mode liquid crystal display device, the pretilt angle of the liquid crystal molecules is preferably set to 75 ° or more, preferably 87 ° or more, more preferably 89 ° or more. The above results are obtained for the VA mode liquid crystal display using the negative dielectric anisotropy liquid crystal shown in FIGS. 4A and 4B, and also for the positive liquid crystal display shown in FIGS. 5A and 5B. The same holds true for a VA mode liquid crystal display device using a dielectric anisotropic liquid crystal.

[0050]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] FIG. 48 is a sectional view showing a structure of a liquid crystal display device 30 according to a first embodiment of the present invention. Referring to FIG. 48, a glass substrate 31 carrying a transparent electrode 31a 'made of ITO and an alignment film 31a having been subjected to a rubbing process is shown.
A and a glass substrate 31B carrying an ITO electrode 31b 'and an alignment film 31b having been subjected to the same rubbing treatment.
And the alignment film 31 using the polymer sphere 31C as a spacer.
a, 31b are oriented so that they face each other,
The liquid crystal panel is formed by sealing with a sealing material (not shown). Further, in the liquid crystal panel, a liquid crystal having a positive or negative dielectric anisotropy, for example, a liquid crystal MJ941296 (Δn = 0.080) manufactured by Merck Japan, is provided in a space defined by the alignment films 31a and 31b.
4, Δε = -4) by a vacuum injection method.
Form 2 In such a configuration, the thickness of the liquid crystal layer 32, that is, the cell thickness d is determined by the diameter of the polymer spacer sphere 31C.

Further, the phase difference compensating films 33A and 33 are formed on the upper and lower sides of the liquid crystal panel thus formed.
B, and a polarizer 34A and a phase difference compensation film 33 below the phase difference compensation film 33A.
Above B, an analyzer 34B is formed in an orientation based on the twist center line as shown in FIG. 1 or FIG. That is, the liquid crystal display device of FIG.
Corresponds to the case where the second retardation compensation film is provided between the liquid crystal panel 11 and the analyzer 13B.

[0052]

[Table 1]

Table 1 shows that, in the liquid crystal display device 30 in which the twist angle is set to 45 °, when the thickness d of the liquid crystal layer 32 is variously changed, the operating characteristics and the viewing angle characteristics of each liquid crystal display device are shown. The evaluation results at 25 ° C. are shown. However, in Table 1, the vertical alignment material RN783 manufactured by Nissan Chemical Co., Ltd. is used as the alignment films 31a and 31b, and the polarizing plates 34A and 34B are used.
The results when a G1220DU polarizing plate manufactured by Nitto Denko or an SK-1832AP7 polarizing plate manufactured by Sumitomo Chemical Co., Ltd. are used. In the liquid crystal display device of Table 1, the phase difference compensation films 33A and 33B shown in FIG. 48 are omitted, but the protective film of the polarizing plate performs a certain degree of retardation compensation. For example, the protective film associated with the G1220DU polarizer exhibits a negative retardation of about 44 nm in size, and the SK-1832AP7
The protective film associated with the polarizer shows a negative retardation of about 50 nm in size. No chiral material is added to the liquid crystal layer 32.

Referring to Table 1, the thickness d of the liquid crystal layer 32 is
Rise time T with decreasing _onAnd falling
Time T_offAnd the response speed of the LCD is improved.
It is understood that it is. Also, the thickness d of the liquid crystal layer decreases.
Viewing angle range that gives a contrast ratio of 10 or more
Increase. However, as explained earlier, the liquid crystal layer
As the thickness decreases, the brightness decreases.
Thus, the thickness of the liquid crystal layer 32 is such that the retardation Δn · d
It must be set within the range of about 80 to about 400 nm.
It is necessary.

The polarizing plate protective film having a negative retardation of about 44 or 50 nm is generally made of triacetate cellulose (TAC) and is called a TAC film. Since such a TAC film has a very small retardation, a general TN or STN liquid crystal display device has almost no influence on optical characteristics.
In a conventional TN or STN liquid crystal display device, it is widely used as a protective film of a polarizing plate. Typical T
The AC film has a positive retardation R of 5 to 15 nm in the plane and a negative retardation R 'of 38 to 50 nm in the thickness direction. Retardation R,
The size of R ′ can be changed by changing the film thickness.

However, the present inventor of the present invention has found that, in the VA mode liquid crystal display device, even a slight retardation of such a TAC film affects the viewing angle characteristics or the contrast ratio, and therefore, the optimal TAC film retardation. It has been found that it is necessary to further improve the viewing angle characteristics of the liquid crystal display device by such optimization. However, the TAC film outside the polarizing plate does not change the optical characteristics of the liquid crystal display device.

In a conventional TN or STN mode liquid crystal display device, the TAC film is arranged so that its slow axis is parallel to the absorption axis of an adjacent polarizing plate. It has been found that it is preferable to dispose the TAC film such that its slow axis is orthogonal to the absorption axis of the adjacent polarizing plate. In such a case, the effective retardation of the retardation compensation film is
From the positive retardation of the retardation compensation film, TAC
This value is obtained by subtracting the positive retardation of the film. Therefore, when a standard polarizing plate having such a TAC film is used, the retardation of the phase difference compensation film is set to be smaller than the theoretical optimum value by the two TAC films disposed above and below the liquid crystal panel. Just for the retardation,
It is necessary to increase it in advance. Conversely, when the TAC film is disposed so that its slow axis is parallel to the absorption axis of the adjacent polarizing plate, the effective retardation of the retardation compensation film increases by two TAC films. For this reason, the retardation of the phase difference compensation film must be reduced in advance by a positive retardation for two TAC films with respect to the theoretical optimum value.

FIGS. 49A and 49B show viewing angle characteristics when the cell thickness d is 3 μm and the twist angle is 45 ° in the liquid crystal display device having the structure shown in FIG. However, FIG.
In the above example, no chiral material was added, and the MJ941296 was used for the liquid crystal, and G1220DU was used for the polarizing plate. However, the results of FIGS. 49 (A) and (B) show that the polarizing plates 34A and 34B have the phase difference compensating films 33B and 34B.
This is for the case where B is also used.

In FIG. 49 (A), the area where the contrast ratio is 10 or more is shown in white, and it can be seen that the white area is very wide and a very wide viewing angle characteristic is obtained. Also,
As can be seen from FIG. 49B, in this liquid crystal display device, a contrast ratio close to 2000 can be obtained in the front direction. FIGS. 50A and 50B show a commercially available retardation compensation film (V, manufactured by Sumitomo Chemical Co., Ltd.) in the liquid crystal display device of FIG.
9 shows viewing angle characteristics when AC0) is used as the phase difference compensation films 33A and 33B. However, the LCD panel is 2
Since it has a retardation value Δn · d of 41 nm, the polarizing plates 34A and 34B and the retardation compensation films 33A,
33B, the magnitude of the total retardation value R ′ is 2
It is set to 218 nm, which is close to 41 nm.

As can be seen from FIG. 50A, in this case, the viewing angle region where the contrast ratio exceeds 10 is shown in FIG.
50 (A), the contrast ratio in the front direction of the panel is also 400% as shown in FIG. 50 (B).
It can be seen that it reaches zero. As described above with reference to FIGS. 43 to 47, when the pretilt angle is 75 ° or less, the viewing angle characteristics of the VA mode liquid crystal display device are deteriorated to about the same as the conventional TN mode liquid crystal display device. The phase difference compensation films 34A, 34A, 3
In the configuration having 4B, even when the pretilt angle is 75 °, as shown in FIG. 51, the contrast ratio is 10 (CR =
The region giving 10) is widened, and a viewing angle characteristic satisfactory as a liquid crystal display device can be obtained. However, FIG. 51 shows the case where the thickness of the liquid crystal layer 32 is 3 μm, the twist angle is 45 °, and the pretilt angle is 75 °. [Embodiment 2] Next, a liquid crystal display according to a second embodiment of the present invention will be described.

In this embodiment, in the liquid crystal display device having the structure shown in FIG.
Instead of the same Merck MX95785 (Δn =
0.0813, Δε = -4.6). The other configuration is the same as that of the device shown in FIG. FIG. 52 shows the rise characteristics of the liquid crystal display device according to the present embodiment when the cell thickness d of the liquid crystal layer 32 is 3 μm, and the twist angles are 0 °, 45 °, and 90 °.
It shows about the case. In this example, no chiral material is added to the liquid crystal layer 32. As can be seen from FIG. 52, the rise time T _ON is about 10 ms when the applied voltage is in the range of 4 to 8 V except when the twist angle is 0 °, and the liquid crystal display device has extremely excellent rise characteristics. I understand. On the other hand, in a TN mode liquid crystal display device, the rise time T _ON is generally 20 ms or more.

FIG. 53 shows the falling characteristics of the liquid crystal display according to the present embodiment when the cell thickness d is also 3 μm, when the twist angles are 0 °, 45 ° and 90 °. Also in this example, no chiral material is added to the liquid crystal layer 32. As can be seen from FIG. 53, the fall time T _OFF is 5 m at any twist angle.
s, which indicates that the liquid crystal display device has extremely excellent falling characteristics. In contrast, in a TN mode liquid crystal display device, the fall time T _OFF is generally 40
ms or more.

[0063]

[Table 2]

Table 2 shows the viewing angle characteristics, particularly the viewing angle characteristics when the total value of the negative retardation R 'formed by the polarizing plates 34A and 34B and the phase difference compensation films 33A and 33B is changed in the liquid crystal display device according to the present embodiment. 9 shows changes in a viewing angle range that gives a contrast ratio of 10 and 11 grayscale inversion angles. The eleventh grayscale inversion angle indicates a polar angle direction in which, when halftones are performed in the front direction of the liquid crystal panel by eleven grayscales, the luminances of the grayscales constituting such halftones appear to be inverted with respect to each other. When such gradation inversion occurs, the display is crushed and it becomes difficult to see. For this reason, the wider the grayscale inversion angle, the better. However, in this embodiment, the retardation Δn · d of the liquid crystal layer 32 is positive and has a value of 246 nm. Table 2
Are the phase difference compensation films 33A and 33B and the polarizing plate 3
By setting the total value of the retardation R ′ formed by 4A and 34B close to the retardation Δn · d of the liquid crystal layer 32, it can be seen that the viewing angle is increased at azimuth angles of 90 °, −90 °, and 180 °. .

[0065]

[Table 3]

Table 3 shows the viewing angle characteristics and the change in the eleventh gradation inversion angle when the twist angle is changed in this embodiment. The results in Table 3 show that there is substantially no viewing angle dependence due to the twist angle. However, the results in Table 3 show that the retardation compensation films 33A and 33B were not provided, and the retardation compensation action of the polarizing plates 34A and 34B (R '= 88 nm).
Only when there is. [Embodiment 3] FIG. 54 shows a structure of a liquid crystal display device 40 according to a third embodiment of the present invention. However, in FIG. 54, the same reference numerals are given to the parts described above, and description thereof will be omitted.

Referring to FIG. 54, the liquid crystal display device 40 has a configuration similar to that of the liquid crystal display device 30 described in FIG. 48. A first retardation compensation film (33B) having a retardation of ₁ and a second retardation compensation film (33B) having a negative retardation
B) ₂ and the positive retardation compensation film (33B) ₁
Are provided near the liquid crystal panel 31 and the negative retardation compensation film (33B) ₂ is provided outside the liquid crystal panel 31. The phase difference compensation film (33B) ₂ is the liquid crystal panel 31
The phase difference compensation film (33B) ₁ has an optical axis parallel to the main surface of the liquid crystal panel 31.

FIG. 55 shows a black display state (non-driving state) for various polar angles when the thickness d of the liquid crystal layer 32 is 3.5 μm and the twist angle is 45 ° in the liquid crystal display device 40 of FIG. ) Shows the transmittance. However, in FIG. 55, the retardation of the positive phase difference compensation film (33B) ₁ is set to 100 nm, and the optical axis angle θ is variously changed. The optical axis angle θ is defined as the angle formed by the optical axis of the phase difference compensation film (33B) ₁ with respect to the twist center axis as shown in FIG. At this time, the retardation value of the negative retardation film (33B) ₂ is set substantially equal to the retardation Δn · d of the liquid crystal panel 31, and the transmittance shown in the figure is in the 90 ° azimuth direction. .

Referring to FIG. 55, it can be seen that the transmittance in the black display state becomes minimum when the optical axis angle θ is about 45 ° at any polar angle. As described above, by minimizing the transmittance of black display for all viewing angles, it is possible to realize an improvement in viewing angle characteristics. In FIG. 55, when the polar angles are 0 ° and 20 °, the transmittance in the black display state is minimized even at an optical axis angle of about 135 °. To get bigger,
The desired viewing angle characteristics are not improved.

FIG. 56 shows the transmittance in the black display state for various polar angles when the retardation of the positive phase difference compensation film (33B) ₁ is changed in the liquid crystal display device 40 of FIG. However, also in the case of FIG. 56, the azimuth is set to 90 °. Referring to FIG. 56, the retardation value of the positive retardation compensation film (33B) ₁ is set to 20 to
By setting the range to 60 nm, the transmittance in the black display state can be minimized for all polar angles. In this case, the transmittance is below 0.002.

FIG. 57 shows the viewing angle characteristics of the liquid crystal display device 40 of FIG. However, in the characteristic of FIG. 57, the retardation R of the positive phase difference compensation film (33B) ₁ is 25n.
m, the retardation R ′ of the negative retardation compensation film (33B) ₂ is 240 nm. Further, the twist angle of the liquid crystal molecules is 45 °, and the thickness of the liquid crystal layer 32 is 3 μm. As can be seen from FIG. 57, a very wide viewing angle can be obtained by using a combination of the positive and negative phase difference compensation films.

On the other hand, when the same positive and negative phase difference compensating films are arranged in the reverse order, the viewing angle characteristics of the liquid crystal display device 40 are significantly reduced as shown in FIG. For this reason, when combining the positive and negative retardation compensation films in the liquid crystal display device 40, the positional relationship is important, and the negative retardation compensation film (33B)
₂ positive it can be seen that there is a need to provide the outside of the retardation film (33B) _1.

FIG. 59 shows viewing angle characteristics when the phase difference compensation film is omitted in the liquid crystal display device 40 of FIG. As can be seen from FIG. 59, the viewing angle characteristics are:
In this case, it becomes very narrow. [Embodiment 4] FIG. 60 further shows the liquid crystal display device 4 of FIG.
0, a liquid crystal display device 5 having a configuration in which another negative retardation compensation film (33A) ₂ having negative retardation is also provided between the lower polarizing plate 34A and the liquid crystal panel 31.
Indicates 0.

FIG. 61 shows that, in the liquid crystal display device 40, the total retardation value of the another negative phase difference compensation film and the phase difference compensation film (33B) ₂ is set substantially equal to the retardation value of the liquid crystal panel 31. In this case, the transmittance in the black display state is shown as a function of the retardation value of the positive phase difference compensation film (33B) ₁ .

As can be seen from FIG. 61, with this configuration, the transmittance in the black display state is minimized when the retardation of the phase difference compensation film (33B) ₁ is in the range of 50 to 60 nm. That is, in order for the retardation compensation film (33B) _{1 to} be effective, the retardation value of the retardation compensation film (33B) ₁ should be set to about 100.
It needs to be set to nm or less.

FIG. 62 shows the liquid crystal display device 50 of FIG. 60 in which the retardation value of the phase difference compensation film (33B) ₁ is fixed at 30 nm, and the retardation value of the negative phase difference compensation films (33B) ₂ and (33A) ₂ is fixed. This shows the transmittance in the black display state when the retardation value R 'is changed. However, as in the previous case, the transmittance is in the 90 ° azimuthal direction, and the value of the polar angle is changed in various ways.

As can be seen from FIG. 62, the transmittance is minimized when the value of the negative retardation R 'formed by the retardation film (33B) ₂ is about 250 nm. , The retardation Δn of the liquid crystal layer 32
・ Slightly smaller than the value of d. As described above, when the positive retardation compensation film (33B) ₁ is not provided, the optimal retardation value of the retardation compensation film (33B) ₁ is equal to the retardation value Δn · d of the liquid crystal layer 32. . That is, the negative retardation compensation film (33)
B) _2, (if 33A) in addition to the ₂ positive using retardation film (33B) _1, a negative retardation film (3
3B) The optimum value of ₂ is the retardation value Δ of the liquid crystal layer 32.
It must be set slightly smaller than n · d. In any case, the total retardation value R 'of the negative retardation compensation film is determined by the liquid crystal layer 32 regardless of whether only the retardation compensation film (32B) ₂ is used or if another negative retardation compensation film is used. Of the retardation value Δn · d of
Must be set to less than twice.

FIG. 63 shows viewing angle characteristics of the liquid crystal display device 50 of FIG. As compared with the result of FIG. 19 showing the corresponding viewing angle characteristics when only the negative retardation compensation film is used, it can be seen that the area of the region where the contrast ratio is 10 or more is enlarged. [Embodiment 5] FIG. 64 shows a structure of a liquid crystal display device 50 'according to a fifth embodiment of the present invention. However, the portions described earlier in FIG. 64 are denoted by the corresponding reference numerals, and description thereof will be omitted.

Referring to FIG. 64, the liquid crystal display device 50 '
Is the liquid crystal panel 31 and the negative retardation compensation film
(33A)_TwoBetween the positive retardation compensation film (33
A) ₁Excellent viewing angle characteristics shown in FIG. 65
Is obtained. Embodiment 6 FIG. 66 shows a liquid crystal according to a sixth embodiment of the present invention.
2 shows a configuration of a display device 60. However, the description in FIG.
Corresponding reference numerals are attached to the parts described above, and the description is omitted.
You.

Referring to FIG. 66, in this embodiment, in the liquid crystal display devices 50 and 50 'described above,
Instead of providing the positive retardation compensation film (33B) ₁ and the negative retardation compensation film (33B) ₂ , a single biaxial retardation compensation film 33B 'is provided between the liquid crystal panel 31 and the polarizing plate 34B. Insert Phase difference compensation film 33
B 'has an optical biaxial, x, y, a refractive index n _X in each direction of the z, n _y, for _{n z, n X> n y} > n z or n _y> n _X> n _z holds. Such a biaxial retardation compensation film is known, and is disclosed, for example, in JP-A-59-189.
325 may be used.

The biaxial retardation compensation film 33B '
Is formed by the formula R =
| N_X-N_y| · D, and the liquid crystal panel 3
R ′ = ｛(n_X+
n_y) / 2-n_z｝ · D. In this embodiment,
The in-plane retardation value is 120 nm or less,
The retardation is the retardation Δn · d of the liquid crystal layer 32.
Optimum results are obtained by setting
However, in the example of FIG. 66, the phase difference compensation film 33B '
Is such that the in-plane slow axis is substantially parallel to the absorption axis of the polarizing plate 34B.
It is arranged to become. The in-plane slow axis is n_X> N_y> N
_zWhen the relationship holds, the x-axis and n _y> N_X>
n_zIs satisfied, it coincides with the y-axis.

[0082] Figure 67, in the liquid crystal display device 60 of FIG. 66, in the case of changing the azimuth angle of the in-plane slow axis n _x of the biaxial retardation film 33B ', the transmittance in the black display mode Is shown. As can be seen from FIG. 67, the biaxial retardation film 33B 'is the azimuth angle θ of about 45 ° or 135 ° in the plane slow axis n _x, i.e. to perpendicular to the absorption axis of the adjacent polarizing plate 34B Or in parallel with each other, the transmittance in the black display mode can be minimized. In particular, by setting the azimuth angle θ to about 45 °, the transmittance in the black display mode can be suppressed to 0.2% or less over the entire range of polar angles from 80 ° to 0 °.

FIG. 68 shows the transmittance in the black display mode when the thickness of the biaxial retardation film 33B 'is changed in the liquid crystal display device 60 of FIG. As can be seen from FIG. 68, the transmittance becomes minimum at a thickness of about 130 μm, but the biaxial retardation film 33B ′ has an
240 nm retardation R or R 'in the thickness direction
Is generated. When the above result is generalized, the in-plane retardation R of the liquid crystal display device 60 of FIG.
m, preferably in the range of 20 to 60 nm, the retardation R ′ in the thickness direction is defined as the retardation Δn of the liquid crystal layer 32.
The transmittance in the black display mode can be minimized by setting d to be twice or less.

FIG. 69 shows the viewing angle characteristics of the liquid crystal display device 60 of FIG. However, in FIG. 69, n _x = 1.50
_{2, n y = 1.5017, n} z = 1.5, d = 120n
m. d is the thickness of the liquid crystal layer 32. As can be seen from FIG. 69, the liquid crystal display device 60 has excellent viewing angle characteristics. As the biaxial retardation film, a retardation film obtained by biaxially stretching polycarbonate (for example, a VAC film manufactured by Sumitomo Chemical Co., Ltd.) or a TAC film serving as a protective film for a polarizing plate can be used. [Embodiment 7] FIG. 70 shows a structure of a liquid crystal display device 70 according to a seventh embodiment of the present invention. However, the parts described earlier in FIG. 70 are denoted by the same reference numerals, and description thereof will be omitted.

Referring to FIG. 70, in this embodiment, in addition to the phase difference compensation film 33B ', an optical biaxial phase difference compensation film 33A' is arranged between the liquid crystal panel 31 and the polarizer 34A. In that case, the phase difference compensation film 3
3B ′ and 33A ′ are such that the slow axis of film 33B ′ is substantially orthogonal to the absorption axis of the adjacent analyzer, and the slow axis of film 33A ′ is orthogonal to the absorption axis of the adjacent polarizer. It is arranged as follows.

FIG. 71 shows the viewing angle characteristics of the liquid crystal display device 70. As can be seen from FIG. 71, the liquid crystal display device 70 provides excellent viewing angle characteristics. [Eighth Embodiment] FIG. 72 shows a structure of a liquid crystal display device 80 according to an eighth embodiment of the present invention. However, the parts described earlier in FIG. 72 are denoted by the same reference numerals, and description thereof will be omitted.
Referring to FIG. 72, the liquid crystal display device 80 is different from the liquid crystal display device 40 of FIG.
B) ₂ is omitted.

FIG. 73 shows a black display mode of the liquid crystal display device 80.
The transmittance in the positive phase difference compensation film (33
B)₁While rotating the film (33B)
₁N _xIt is obtained while changing the azimuth of the axis.
You. As can be seen from FIG. 73, the liquid in the black display mode
The transmittance of the crystal panel is n_xIs about the twist center axis.
Minimum when 45 ° or about 135 °
become. Of these, 0 ° especially at an azimuth of 45 °
Transmittance is minimum for all polar angles in the range of ~ 80 °
Therefore, it is most preferable.

FIG. 74 shows the transmittance of the liquid crystal display device 80 in the black display mode measured by the positive retardation compensation film (3).
3B) Shown as a function of ₁ thickness. Referring to FIG. 74, the transmittance of the liquid crystal display device 80 in the black indication mode is 140 to ₁ for the phase difference compensation film (33B) ₁ .
It can be seen that the minimum is obtained when the thickness is 50 μm. In-plane retardation R of phase difference compensation film (33B) ₁
Is 140 to 160 when the thickness is 140 to 150 μm.
It is in the range of μm. That is, when only the positive retardation compensation film (33B) ₁ is used in the liquid crystal display device 80, the in-plane retardation of the film (33B) ₁ is 3
It is preferably within 00 nm.

FIG. 75 shows the viewing angle characteristics of the liquid crystal display device 80 optimized according to FIGS. As can be seen from FIG. 75, the viewing angle characteristics of the liquid crystal display device 80 are significantly improved as compared with the case where the retardation compensation film shown in FIG. 59 is not provided. [Embodiment 9] FIG. 76 shows a structure of a liquid crystal display device 90 according to a ninth embodiment of the present invention.

Referring to FIG. 76, a liquid crystal display device 90
The liquid crystal display device 80 shown in FIG.
It has a configuration in which a positive retardation compensation film (33A) ₁ shown at 0 'is added. However, the retardation compensation film (3
3B) ₁ is analyzer 34 which plane slow axis n _x is adjacent
So as to be perpendicular to the absorption axis of B, also retardation film (33A) ₁ in-plane slow axis n _x is arranged perpendicular to the absorption axis of the adjacent polarizer 34A.

FIG. 77 shows the viewing angle characteristics of the liquid crystal display device 90. Referring to FIG. 77, the viewing angle characteristics of the liquid crystal display device 90 are greatly improved as compared with the viewing angle characteristics when the retardation compensation film shown in FIG. 59 is not provided. [Embodiment 10] FIG. 78 shows a structure of a liquid crystal display device 100 according to a tenth embodiment of the present invention.

Referring to FIG. 78, the liquid crystal display device 100
Has a configuration similar to that of the liquid crystal display device 90 described above, except that the retardation compensation film (33B) _{1 is connected} to the in-plane slow axis n.
_x forms an angle of 45 ° with the absorption axis of the adjacent analyzer 34B, and the phase difference compensation film (33A)
_1, the in-plane slow axis n _x is different in that is disposed so as the angle of the absorption axis 45 ° of the adjacent polarizer 34A.

FIG. 79 shows the viewing angle characteristics of the liquid crystal display device 100.
With a retardation compensation film (33A) ₁, (33B)₁of
When the retardation values R are each 75 nm,
Shown. As can be seen from FIG. 79, the liquid crystal display device 10
The viewing angle characteristic of 0 is obtained by setting the phase difference compensation film shown in FIG.
The comparison of the viewing angle characteristics with no
Although slightly inferior to those of the other examples
You. [Embodiment 11] FIG. 80 shows an eleventh embodiment of the present invention.
Active matrix drive type liquid crystal display device 110
The configuration is shown.

In this embodiment, in the configuration of FIG. 80, a plurality of transparent pixel electrodes (31) corresponding to the pixels defined in the liquid crystal panel are formed on the glass substrate 31A or 31B.
a ') _PIXEL and TFT driving it (31a')
_{A TFT} is formed. That is, the transparent pixel electrode (3
1a ') _PIXEL and TFT (31a') _TFT
Correspond to the electrodes 31a 'or 31b'. Further, on the substrate 31A or 31B, a data bus DATA for supplying a drive signal to the TFTs arranged in a matrix and an address bus ADDR for activating the data bus DATA extend.

FIG. 81 shows the viewing angle characteristics of the liquid crystal display device 110 in a case where Merck Japan MJ95785 is used as the liquid crystal and the thickness of the liquid crystal layer is 3 μm. In this case, the twist angle of the liquid crystal molecules is 45 °, the retardation Δn · d of the liquid crystal layer 32 is 241 nm, and Nissan Chemical RN783 is used as the molecular alignment films 31a and 31b (see FIG. 48). As can be seen from FIG. 61, an active matrix drive liquid crystal display having a very wide viewing angle range can be obtained. Embodiment 12 In each of the embodiments described above, as shown in FIGS. 82A to 82C, a so-called single domain molecular alignment configuration in which the liquid crystal molecular alignment is uniform in each pixel. I was using it. Note that FIG. 82A is a plan view of a region for one pixel of a liquid crystal display device, and FIG.
FIG. 82 (C) is a cross-sectional view taken along line AB in FIG. 82 (A), and FIG. 82 (C) shows a configuration in the case where incident light X and Y are made incident on the liquid crystal display device of FIG. 82 (B) from two different directions. The parts described above and described earlier in the figures are denoted by the same reference numerals. In FIG. 82A, the solid arrow indicates the upper substrate 3
The rubbing direction of the molecular alignment film 31b supported on 1B is
The dotted arrow indicates the rubbing direction of the molecular alignment film 31a carried on the lower substrate 31A. The rubbing direction of the molecular alignment film 31b and the rubbing direction of the molecular alignment film 31a are α
Intersect at an angle of ₁ , but the twist angle of liquid crystal molecules is 45 °
, The angle α ₁ is set to 45 °.

As can be seen from FIG. 82 (C), in the liquid crystal display device having such a single-domain molecular alignment configuration, in the driving state, the molecular alignment viewed from the direction of the incident light X and the incident light Y Since the molecular orientation viewed from the direction is different, a substantial reduction in viewing angle characteristics is inevitable. On the other hand, FIGS. 83A to 83C show a configuration of a liquid crystal display device 120 according to the twelfth embodiment of the present invention. However, the same reference numerals are given to the parts described above, and the description will be omitted.

In the configuration shown in FIGS. 83 (A) to 83 (C), FIG.
As shown in (B), in each pixel, ultraviolet-modified molecular alignment films 31a 'and 31b' are formed so as to cover a part of the molecular alignment films 31a and 31b, respectively. Such UV-modified molecular alignment films include, for example, the molecular alignment films 31a and 31.
After rubbing b, another molecular alignment film is deposited thereon,
It may be formed by irradiating this with ultraviolet rays to change the molecular orientation, and then patterning each pixel so as to leave only a part thereof.

At this time, as shown in the sectional view of FIG. 83 (B), the modified molecular orientation film 31a 'is formed in a region below the plane of the plan view of FIG. By forming the modified molecular alignment film 31b 'in the region, the structure shown in FIG.
When the incident lights X and Y are made incident from different directions as shown in FIG. 3 (C), the liquid crystal molecular orientations that are perceived by the light in any of the above directions become equal in the driving state of the liquid crystal display device, The viewing angle characteristics of the liquid crystal display device are further improved.

FIGS. 84A to 84C show a modification of this embodiment. Referring to FIG. 84 (A), in this embodiment, the rubbing direction is changed in the upper region and the lower region in the drawing. As a result, as shown in the cross-sectional view of FIG. The molecular orientation differs between the right region and the left region (corresponding to the upper region and the lower region in FIG. 84A) in each pixel. As a result, as shown in FIG.
When the incident lights X and Y are incident from two different directions, the orientation of the liquid crystal molecules in each direction is as shown in FIG.
This is equivalent to the case of (C), and the viewing angle characteristics of the liquid crystal display device are improved.

FIG. 85 shows a liquid crystal display device having the structure of FIG. 84 in which the angles α ₁ and α ₂ are both 45 ° and the liquid crystal layer 32
3 shows viewing angle characteristics when the thickness d of the sample is 3 μm. However, in FIG. 85, the liquid crystal display device uses MJ95785 manufactured by Merck Japan Ltd. as the liquid crystal layer 32, and no chiral material is added. That is, in this case, the liquid crystal layer 32 has a value of 287 nm as the retardation Δn · d, and the twist angle is set to 45 °. Further, the positive and negative phase difference compensation films shown in FIG. 64 were combined with the positive phase difference compensation films (33A) ₁ and (33A) _{1 so that} the total retardation value R was 25 nm and the negative phase difference compensation film (33
B) ₂ , so that the total retardation value R ′ is 160 nm.

Referring to FIG. 85, it can be seen that by configuring the liquid crystal display device in this way, the region where the contrast ratio is less than 10 is very limited, and very excellent viewing angle characteristics can be obtained. FIG. 86 shows the result of a simulation of the viewing angle characteristics of the liquid crystal display device having the same configuration. According to this, it can be seen that the liquid crystal display device can realize more excellent viewing angle characteristics by optimizing each member. .

FIG. 87 shows the structure of a direct-view liquid crystal display device 130 using the liquid crystal display devices described in the first to twelfth embodiments. Referring to FIG. 87, the direct-view type liquid crystal display device 130 includes the liquid crystal display devices 10 to 120.
VA mode liquid crystal display device 101
And a surface light source 103 provided behind the light source. A plurality of pixel regions 102 are defined in the liquid crystal display device 101, and optically modulates a backlight emitted from the surface light source 103. On the other hand, the surface light source 103 includes a light source unit 103 including a line light source such as a fluorescent tube, and a light diffusion unit that diffuses light emitted from the line light source and illuminates the entire surface of the liquid crystal display device 101 two-dimensionally. 104.

VA according to the present invention described in each embodiment above
Since the mode liquid crystal display device gives a particularly wide viewing angle characteristic, it is particularly suitable for a direct-view type liquid crystal display device having a configuration as shown in FIG. In each of the above embodiments, the liquid crystal layer 32
Used a liquid crystal having a negative dielectric anisotropy, but as described above, the present invention is not limited to such a liquid crystal having a negative dielectric anisotropy. It is also possible to use a liquid crystal having a rate anisotropy (a so-called p-type liquid crystal). The positive and negative of the dielectric anisotropy are related to the driving method shown in FIGS. 4 and 5, but are not related to the optical characteristics described in FIGS. The optimization of the compensation film is similarly established even when a liquid crystal having a positive dielectric anisotropy is used.

In the present invention, FIG.
In Example 4, a birefringent film having a retardation of 120 nm or less was used as a retardation compensation film (33).
A) ₁ or (33B) ₁ is used, but it has conventionally been difficult to produce such a retardation compensation film having a very small birefringence. On the other hand, the inventor of the present invention has noticed that a resin having a norbornene structure in the main chain is almost optically isotropic, and using the norbornene resin, the optimal retardation compensation film ( 33
A) ₁ and (33B) ₁ were successfully produced. [Embodiment 13] FIG. 88 shows a structure of a liquid crystal display device 140 according to a thirteenth embodiment of the present invention. However, in FIG.
The same reference numerals are given to the parts described above, and the description will be omitted.

Referring to FIG. 88, a liquid crystal display 140
Has the configuration similar to the liquid crystal display device 40 of FIG. 54, the phase difference compensation film having retardation retardation film (33B) ₁ of the slow axis with R ₁ and (n _x) the retardation R ₂ ( 33B) ₂ of the slow axis and (n _x), but is arranged perpendicular to each other. FIG.
9 is the transmittance Tb of the liquid crystal display device 140 in black display.
The retardation R ₂ of the retardation compensation film (33B) ₂ was set to 150 nm, and the retardation compensation film (33B)
The retardation R ₁ of B) ₁ shows the case where variously changed.

Referring to FIG. 89, it can be seen that the transmittance Tb becomes minimum when the sum of the retardations R ₁ and R ₂ is substantially equal to the retardation Δn · d of the liquid crystal layer 32. FIG. 90 shows the retardation compensation films (33B) ₁ and (33B) _{2 in} the liquid crystal display device 140 of FIG.
91A, 91B, 92A, and 92B.
7 shows the polar angle dependence of the black display transmittance Tb when variously changed as shown in FIG.

Referring to FIG. 90, the polar angle dependence of the transmittance Tb, that is, the viewing angle characteristic of the liquid crystal display device 140 is as follows.
The liquid crystal layer 32 shown in FIG. 91B or FIG.
The retardation axis of the retardation compensation film (33B) ₁ on the side closer to the liquid crystal layer 32 is opposite to the absorption axis of the polarizing plate 34B disposed on the same side as the retardation compensation film (33B) ₁ with respect to the liquid crystal layer 32. It can be seen that the configuration is greatly improved in the orthogonal configuration. On the other hand, in the configuration of FIG. 92 (C), the polar angle dependence of the transmittance Tb is worse than in the case where the retardation compensation film is not provided.

FIG. 93 (A) shows the viewing angle characteristics of the liquid crystal display device 140 in comparison with the viewing angle characteristics of the liquid crystal display device without the retardation compensation film shown in FIG. 93 (B).
However, in FIGS. 93 (A) and (B), the hatched portions indicate regions where the contrast ratio is 1 or less. FIG. 93 (A),
Comparing (B), it can be seen that the liquid crystal display device 140 has more excellent viewing angle characteristics than the liquid crystal display device having a configuration without the retardation compensation film.

The characteristic shown in FIG. 93A can be obtained by using a liquid crystal having a negative dielectric anisotropy or a liquid crystal having a positive dielectric anisotropy for the liquid crystal layer 32. Obtained similarly. [Embodiment 14] FIG. 94 shows a structure of a liquid crystal display device 150 according to a fourteenth embodiment of the present invention. However, in FIG.
The same reference numerals are given to the parts described above, and the description will be omitted.

Referring to FIG. 94, the liquid crystal display device 150
Uses a p-type liquid crystal composed of p-type liquid crystal molecules 32a as the liquid crystal layer 32, and controls the tilt angle of the liquid crystal molecules by a voltage applied to the electrodes 31a 'and 31b' formed on the glass substrates 31A and 31B. At this time, the p liquid crystal molecules 32a are substantially vertically moved in the non-driving state due to the interaction with the molecular alignment film (not shown) formed so as to cover the glass substrate 31A or 31B and the electrodes thereon. Orientation. Further, in the configuration of FIG. 94, a positive phase difference compensation film (33B) ₁ and a negative phase difference compensation film (33B) ₂ similar to the configuration of FIG. 54 are disposed on the upper glass substrate 31B.

FIG. 95 shows viewing angle characteristics of the liquid crystal display device 150 of FIG. However, the characteristic shown in FIG.
A liquid crystal ZLI- having a positive dielectric anisotropy manufactured by Merck
Using 4792, the retardation R of the retardation compensation film (33B) ₁ is 25 nm, and the retardation compensation film (33B) is
B) The case where the retardation R ′ of ₂ is 240 nm. In FIG. 95, JALS204 made by Japan Synthetic Rubber Co., Ltd. is used as the molecular alignment film, and the thickness of the liquid crystal layer 32 is set to 3.5 μm.

Referring to FIG. 95, the liquid crystal display device 150
It can be seen that the viewing angle characteristic has a pattern similar to that described in the previous embodiment, that is, for example, a pattern similar to the viewing angle characteristic in FIG. A similar excellent viewing angle characteristic pattern is
It can be obtained also in the liquid crystal display device shown in FIGS. Further, it is easy to transform the liquid crystal display device shown in FIGS. 5A and 5B or FIG. 94 into an active matrix configuration shown in FIG. Also in this case, a similar excellent viewing angle pattern is selected.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to such an embodiment, and various modifications or changes can be made within the scope of the claims.

[0114]

According to the first to third aspects of the present invention, a positive refractive index anisotropy is provided adjacent to a liquid crystal panel including a liquid crystal layer having a positive or negative dielectric anisotropy. A wide viewing angle can be realized in a vertical alignment type liquid crystal display device by sequentially arranging a retardation plate having the same and a retardation plate having a negative refractive index anisotropy from the liquid crystal panel side.

According to the features of the present invention, optically biaxial phase difference compensation is provided adjacent to a liquid crystal panel including a liquid crystal layer having a positive or negative dielectric anisotropy. By disposing the film, a wide viewing angle can be realized in the vertical alignment type liquid crystal display device. Claim 7
According to the features described in Nos. 27 to 27, in a vertical alignment type liquid crystal display device exhibiting positive or negative dielectric anisotropy, by setting the retardation of the liquid crystal layer to 80 nm or more and 400 nm or less, a wide viewing angle and high-speed response can be obtained. A bright, high-contrast liquid crystal display device having characteristics, without coloring, can be obtained. In particular, the contrast ratio of the liquid crystal display device can be optimized by optimizing the orientation of the polarizing plate with respect to the twist center line of the liquid crystal molecules. Further, as described in claim 10, an optically uniaxial positive phase difference compensation film and a negative phase difference compensation film are sequentially disposed adjacent to the liquid crystal layer. 23. An optically biaxial retardation compensation film is disposed adjacent to the liquid crystal layer as described in claim 17, or the positive retardation is disposed adjacent to the liquid crystal layer as described in claim 22. By providing the compensation film, the viewing angle characteristics of the liquid crystal display device can be greatly improved. Claims 11, 12, 15, 18, 1
By optimizing the orientation of such a retardation compensation film as described in 9, 23 or 24, or as described in claim 13, 16, 20, 21, or 25, By optimizing the retardation, the transmittance in the black display mode can be reduced, and the contrast ratio of the liquid crystal display device can be improved. Further, by using a resin having a norbornene structure in the main chain for the retardation compensation film as described in claim 14 or 26, a retardation compensation film having a desired very low retardation can be formed. .

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a basic configuration of a liquid crystal display device according to the present invention.

FIG. 2 is a diagram illustrating a relationship between a contrast ratio of the liquid crystal display device of FIG. 1 and an orientation of a polarizer and an analyzer with respect to a liquid crystal panel.

FIG. 3 is a diagram showing dynamic characteristics of the liquid crystal display device of FIG.

FIG. 4 is a diagram illustrating the operation of a VA mode liquid crystal display device of the present invention using a liquid crystal having negative dielectric anisotropy.

FIG. 5 is a diagram illustrating an operation of a VA mode liquid crystal display device of the present invention using a liquid crystal having a positive dielectric anisotropy.

6 is a diagram showing a configuration in which a phase difference compensating plate is further provided in the liquid crystal display device of FIG.

FIG. 7 is a view showing viewing angle characteristics when the ratio of the total retardation value of the phase difference compensator to the retardation value of the liquid crystal panel is 0.45 in the liquid crystal display device of FIG. 6;

8 is a diagram illustrating viewing angle characteristics when the ratio of the total retardation value of the retardation compensator to the retardation value of the liquid crystal panel is 0.6 in the liquid crystal display device of FIG. 6;

9 is a diagram showing viewing angle characteristics when the value of the ratio of the total retardation value of the retardation compensator to the retardation value of the liquid crystal panel in the liquid crystal display device of FIG. 6 is 0.75.

10 is a diagram showing viewing angle characteristics when the ratio of the total retardation value of the retardation compensator to the retardation value of the liquid crystal panel in the liquid crystal display device of FIG. 6 is 0.82.

11 is a diagram showing viewing angle characteristics when the value of the ratio of the total retardation value of the phase difference compensator to the retardation value of the liquid crystal panel is 0.90 in the liquid crystal display device of FIG.

12 is a diagram showing viewing angle characteristics when the ratio of the total retardation value of the retardation compensator to the retardation value of the liquid crystal panel is 0.97 in the liquid crystal display device of FIG. 6;

13 is a diagram showing viewing angle characteristics when the ratio of the total retardation value of the phase difference compensator to the retardation value of the liquid crystal panel is 1.05 in the liquid crystal display device of FIG.

14 is a diagram illustrating viewing angle characteristics when the ratio of the total retardation value of the phase difference compensator to the retardation value of the liquid crystal panel is 1.12 in the liquid crystal display device of FIG.

FIG. 15 is a diagram showing viewing angle characteristics when the ratio of the total retardation value of the retardation compensator to the retardation value of the liquid crystal panel is 1.20 in the liquid crystal display device of FIG. 6;

FIG. 16 is a view showing viewing angle characteristics when the ratio of the total retardation value of the retardation compensator to the retardation value of the liquid crystal panel is 1.34 in the liquid crystal display device of FIG.

17 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 1 μm and the retardation value of the liquid crystal layer is 82 nm in the liquid crystal display device of FIG.

18 is a view showing viewing angle characteristics when the thickness of the liquid crystal layer is 2 μm and the retardation value of the liquid crystal layer is 164 nm in the liquid crystal display device of FIG.

19 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 3 μm and the retardation value of the liquid crystal layer is 246 nm in the liquid crystal display device of FIG.

20 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 4 μm and the retardation value of the liquid crystal layer is 328 nm in the liquid crystal display device of FIG.

21 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 5 μm and the retardation value of the liquid crystal layer is 410 nm in the liquid crystal display device of FIG.

22 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 6 μm and the retardation value of the liquid crystal layer is 492 nm in the liquid crystal display device of FIG.

23 is a diagram showing transmittance characteristics when the thickness of the liquid crystal layer is 1 μm in the liquid crystal display device of FIG.

24 is a diagram showing transmittance characteristics when the thickness of the liquid crystal layer is 2 μm in the liquid crystal display device of FIG.

25 is a diagram showing transmittance characteristics when the thickness of the liquid crystal layer is 3 μm in the liquid crystal display device of FIG.

26 is a diagram illustrating transmittance characteristics when the thickness of the liquid crystal layer is 4 μm in the liquid crystal display device of FIG.

FIG. 27 is a diagram showing transmittance characteristics when the thickness of the liquid crystal layer is 5 μm in the liquid crystal display device of FIG.

28 is a diagram showing transmittance characteristics when the thickness of the liquid crystal layer is 6 μm in the liquid crystal display device of FIG.

29 is a diagram showing coloring characteristics when the thickness of the liquid crystal layer is 1 μm in the liquid crystal display device of FIG.

30 is a diagram showing coloring characteristics when the thickness of the liquid crystal layer is 3 μm in the liquid crystal display device of FIG.

31 is a diagram showing coloring characteristics when the thickness of the liquid crystal layer is 4 μm in the liquid crystal display device of FIG.

32 is a diagram showing coloring characteristics when the thickness of the liquid crystal layer is set to 5 μm in the liquid crystal display device of FIG.

FIG. 33 is a diagram showing coloring characteristics when the thickness of the liquid crystal layer is 6 μm in the liquid crystal display device of FIG.

34 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 3 μm and the twist angle is 0 ° in the liquid crystal display device of FIG.

FIG. 35 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 3 μm and the twist angle is 90 ° in the liquid crystal display device of FIG.

FIG. 36 is a diagram showing viewing angle characteristics when the thickness of the liquid crystal layer is 3 μm and the twist angle is 180 ° in the liquid crystal display device of FIG.

FIG. 37 is a diagram showing the transmittance of the liquid crystal display device of FIG. 6 during black display.

FIGS. 38A and 38B are diagrams showing a molecular orientation in a liquid crystal layer containing a chiral material in a non-driving state and a driving state, respectively, in the liquid crystal display device of FIG.

FIGS. 39 (A) and (B) are diagrams showing a molecular orientation in a liquid crystal layer containing no chiral material in a non-driving state and a driving state, respectively, in the liquid crystal display device of FIG. 6.

40 is a diagram showing viewing angle characteristics when a chiral material is added to a liquid crystal layer in the liquid crystal display device of FIG.

41 is a diagram showing transmittance characteristics when a chiral material is added to a liquid crystal layer in the liquid crystal display device of FIG.

42 is a diagram showing transmittance characteristics when a chiral material is not added to a liquid crystal layer in the liquid crystal display device of FIG.

FIG. 43 is a diagram illustrating viewing angle characteristics when the pretilt angle is set to 90 ° in the liquid crystal display device of FIG. 6;

FIG. 44 is a diagram showing viewing angle characteristics when the pretilt angle is set to 85 ° in the liquid crystal display device of FIG. 6;

FIG. 45 is a diagram illustrating viewing angle characteristics when the pretilt angle is set to 80 ° in the liquid crystal display device of FIG. 6;

FIG. 46 is a diagram showing viewing angle characteristics when the pretilt angle is set to 75 ° in the liquid crystal display device of FIG. 6;

FIG. 47 is a diagram showing viewing angle characteristics of a standard TN mode liquid crystal display device.

FIG. 48 is a view illustrating a configuration of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 49 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG. 48.

50 is a diagram illustrating viewing angle characteristics when a phase difference compensating plate is provided in the liquid crystal display device of FIG. 48.

FIG. 51 is a diagram illustrating viewing angle characteristics when a pretilt angle is set to 75 ° and phase difference compensation films are provided above and below a liquid crystal panel in the liquid crystal display device in FIG. 48.

FIG. 52 is a view illustrating a rising characteristic of the liquid crystal display device according to the second embodiment of the present invention.

FIG. 53 is a view showing fall characteristics of the liquid crystal display device according to the second embodiment of the present invention.

FIG. 54 is a view illustrating a configuration of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 55 is a diagram showing the transmittance of the liquid crystal display device of FIG. 54 in the black display state.

FIG. 56 is another diagram showing the transmittance of the liquid crystal display device of FIG. 54 in the black display state.

FIG. 57 is a diagram showing viewing angle characteristics of the liquid crystal display device of FIG. 54.

FIG. 58 is a diagram illustrating viewing angle characteristics when the order of the positive phase difference compensation film and the negative phase difference compensation film is reversed in the liquid crystal display device of FIG. 54;

FIG. 59 is a diagram showing viewing angle characteristics when the retardation compensation film is omitted in the liquid crystal display device of FIG. 54.

FIG. 60 is a view illustrating a configuration of a liquid crystal display according to a fourth embodiment of the present invention.

FIG. 61 is a diagram showing the transmittance of the liquid crystal display device of FIG. 60 in the black display state.

62 is another diagram showing the transmittance of the liquid crystal display device of FIG. 60 in the black display state.

63 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG.

FIG. 64 is a view illustrating a configuration of a liquid crystal display device according to a fifth embodiment of the present invention.

65 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG. 64.

FIG. 66 is a view illustrating a configuration of a liquid crystal display according to a sixth embodiment of the present invention.

FIG. 67 is a diagram showing transmittance in a black display state in the liquid crystal display device of FIG. 66.

FIG. 68 is another diagram showing the transmittance of the liquid crystal display device of FIG. 66 in the black display state.

69 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG.

FIG. 70 is a view illustrating a configuration of a liquid crystal display device according to a seventh embodiment of the present invention.

FIG. 71 is a diagram showing viewing angle characteristics of the liquid crystal display device of FIG. 70.

FIG. 72 is a view illustrating a configuration of a liquid crystal display according to an eighth embodiment of the present invention.

73 is a diagram showing transmittance in a black display state in the liquid crystal display device of FIG. 72.

74 is another diagram showing the transmittance of the liquid crystal display device of FIG. 72 in the black display state.

75 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG. 72.

FIG. 76 is a view showing a structure of a liquid crystal display according to a ninth embodiment of the present invention.

77 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG. 76.

FIG. 78 is a view showing a structure of a liquid crystal display according to a tenth embodiment of the present invention.

79 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG. 78.

FIG. 80 is a view showing a structure of a liquid crystal display according to an eleventh embodiment of the present invention.

FIG. 81 is a diagram showing viewing angle characteristics of the liquid crystal display device of FIG. 80.

FIG. 82 is a diagram illustrating a configuration of a liquid crystal display device having a single domain configuration.

FIG. 83 is a view showing a configuration of a liquid crystal display device according to a twelfth embodiment of the present invention having a split orientation configuration.

FIG. 84 is a view showing a modification of the liquid crystal display device of FIG. 83.

85 is a diagram illustrating viewing angle characteristics of the liquid crystal display device of FIG. 84.

86 is a diagram showing a simulation result of viewing angle characteristics of the liquid crystal display device of FIG. 84.

FIG. 87 is a diagram showing a configuration of a direct-view type liquid crystal display device using the vertical alignment liquid crystal display device according to the present invention.

FIG. 88 is a view showing a structure of a vertical alignment liquid crystal display according to a thirteenth embodiment of the present invention.

FIG. 89 is a diagram showing black display transmittance characteristics of the liquid crystal display device of FIG. 88.

90 is a diagram showing the polar angle dependence of the black display transmittance of the liquid crystal display device of FIG. 88 for various configurations.

FIGS. 91A and 91B are diagrams (part 1) illustrating various configurations of the liquid crystal display device in FIG. 90;

FIGS. 92 (C) and (D) are diagrams (part 2) showing various configurations of the liquid crystal display device in FIG. 90.

FIGS. 93 (A) and (B) are diagrams showing viewing angle characteristics of the liquid crystal display device of FIG. 88.

FIG. 94 is a view showing a structure of a vertical alignment liquid crystal display according to a fourteenth embodiment of the present invention.

FIG. 95 is a diagram showing viewing angle characteristics of the liquid crystal display device of FIG. 94.

[Explanation of symbols]

 10, 20, 30, 40, 50, 60, 70, 80, 9
0,100,110,120,130,140 Liquid crystal table
Display device 11, 31 Liquid crystal panel 11A, 11B, 31A, 31B Glass substrate 12, 32 Liquid crystal layer 12a, 32a Liquid crystal molecules 13A, 13B, 33A, 33B Polarizing plate 14A, 14B, 34A, 34B, (34A)₁, (3
4B)₁, (34A) _Two, (32B)_Two Phase difference compensation
Films 31a, 31b Molecular alignment films 31a ', 31b' (31a ')_PIXELElectrode (31a ')_TFTTFT 31c Spacer 130 Direct view liquid crystal display device 101 Vertical alignment liquid crystal display device 102 Pixel 103 Surface light source 104 Light source unit 106 Line light source

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takahiro Sasaki, Inventor 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Hideaki Tsuda 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Co., Ltd. (72) Inventor Hideo Senda 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture

Claims (27)

[Claims] A first polarizing plate disposed on a side of the first substrate opposite to a side in contact with the liquid crystal layer, the first and second substrates sandwiching a liquid crystal layer; A second polarizing plate disposed on a side of the second substrate opposite to the side in contact with the liquid crystal layer, wherein a second polarizing plate is disposed between the first substrate and the first polarizing plate. A first retardation plate having a positive refractive index anisotropy is provided in at least one of a first gap and a second gap between the second substrate and the second polarizing plate, A second retardation plate having a refractive index, wherein the second retardation plate is disposed outside the first retardation plate with respect to the liquid crystal layer. Liquid crystal display device. 2. The liquid crystal display device according to claim 2, wherein said liquid crystal layer is made of liquid crystal having a positive dielectric anisotropy. 3. The liquid crystal display device according to claim 2, wherein the liquid crystal layer is made of a liquid crystal having a negative dielectric anisotropy. 4. A first and a second substrate sandwiching a liquid crystal layer, a first polarizer disposed on a side of the first substrate opposite to a side in contact with the liquid crystal layer, and A second polarizing plate disposed on a side of the second substrate opposite to the side in contact with the liquid crystal layer, wherein a second polarizing plate is disposed between the first substrate and the first polarizing plate. Liquid crystal characterized in that an optical biaxial retardation plate is disposed in at least one of a first gap and a second gap between the second substrate and the second polarizing plate. Display device. 5. The liquid crystal display device according to claim 4, wherein the liquid crystal layer is made of liquid crystal having a positive dielectric anisotropy. 6. The liquid crystal display device according to claim 4, wherein the liquid crystal layer is made of a liquid crystal having a negative dielectric anisotropy. 7. A first and second substrate parallel to each other;
First electrode means formed on a first main surface of the first substrate facing the second substrate; and
A second substrate formed on a second main surface facing the first substrate;
And a first molecular alignment film covering the first electrode means on the first main surface of the first substrate;
On the second main surface of the second substrate, the second substrate
A liquid crystal display device comprising: a second molecular alignment film covering the electrode means; and a liquid crystal layer made of liquid crystal molecules sealed between the first and second substrates. A liquid crystal display device having a long axis of liquid crystal molecules oriented substantially perpendicular to one main surface of the substrate, and wherein the liquid crystal layer has a retardation of 80 nm or more and 400 nm or less. 8. The liquid crystal display device according to claim 7, wherein the liquid crystal molecules have a positive dielectric anisotropy. 9. The liquid crystal panel according to claim 1, wherein the first and second substrates form a liquid crystal panel together with the liquid crystal layer interposed therebetween, and the liquid crystal display further comprises a first polarizing plate having a first absorption axis. And a second polarizing plate having a second absorption axis, and the first absorption axis and the second absorption axis are orthogonal to each other on a first side and a second opposite side of the liquid crystal panel, respectively. Wherein the first and second polarizers are arranged such that the first absorption axis has an angle of about 45 ° with respect to a twist center axis bisecting the twist angle in the liquid crystal layer. The liquid crystal display device according to claim 7, wherein the liquid crystal display device is disposed so as to satisfy the following. 10. The liquid crystal display device further includes the first liquid crystal display device.
A first gap having a positive refractive index anisotropy in at least one of a first gap between the first substrate and the first polarizing plate and a second gap between the second substrate and the second polarizing plate. A phase difference plate and a second phase difference plate having negative refractive index anisotropy,
10. The liquid crystal display device according to claim 9, wherein the second retardation plate is disposed farther from the liquid crystal panel than the first retardation plate. 11. The first retardation plate has an optical axis parallel to an absorption axis of a polarizing plate adjacent to the first retardation plate among the first and second polarizing plates. The liquid crystal display device according to claim 10, wherein the liquid crystal display device is disposed in a liquid crystal display. 12. The first phase difference plate such that an optical axis is orthogonal to an absorption axis of a polarization plate adjacent to the first phase difference plate among the first and second polarization plates. The liquid crystal display device according to claim 10, wherein the liquid crystal display device is provided. 13. The device according to claim 10, wherein the first retardation plate has a retardation of 120 nm or less.
13. The liquid crystal display device according to claim 12, wherein 14. The liquid crystal display device according to claim 13, wherein the first retardation plate is made of a resin having a norbornene structure in a main chain. 15. The apparatus according to claim 15, wherein the second retardation plate is disposed such that an optical axis is substantially orthogonal to at least one of the first and second main surfaces. 10
15. The liquid crystal display device according to claim 14. 16. The liquid crystal display device according to claim 10, wherein the second retardation plate has a retardation that is twice or less than a retardation of a liquid crystal layer. 17. The liquid crystal display according to claim 17, further comprising:
An optical biaxial retardation plate is disposed in at least one of a first gap between the first substrate and the first polarizing plate and a second gap between the second substrate and the second polarizing plate. The liquid crystal display device according to claim 9, wherein: 18. The optical biaxial retardation plate has a slow axis included in a plane parallel to the first or second main surface, and the slow axes are the first and second principal axes. 18. The liquid crystal display device according to claim 17, wherein the second polarizing plate extends parallel to an absorption axis of a polarizing plate adjacent to the optically biaxial retardation plate. 19. The optical biaxial retardation plate has a slow axis included in a plane parallel to the first or second main surface, and the slow axes are the first and second principal axes. 18. The liquid crystal display device according to claim 17, wherein the second polarizing plate is orthogonal to an absorption axis of a polarizing plate adjacent to the optically biaxial retardation plate. 20. The optical biaxial retardation plate according to claim 12, wherein
The liquid crystal display device according to any one of claims 17 to 19, wherein the liquid crystal display device has an in-plane retardation of 0 nm or less. 21. The optical biaxial retardation plate has a retardation of not more than twice the retardation of a liquid crystal layer in a direction orthogonal to the first or second main surface. Item 22. The liquid crystal display device according to any one of Items 17 to 21. 22. The liquid crystal display device, further comprising:
A first and a second optically uniaxial retardation plate in a first gap between the first substrate and the first polarizer and in a second gap between the second substrate and the second polarizer, respectively. The liquid crystal display device according to claim 9, further comprising: 23. Both the first and second optically uniaxial retardation plates are retarded in phase with respect to the absorption axis of an adjacent one of the first and second polarization plates. 23. The liquid crystal display device according to claim 22, wherein the liquid crystal display device is arranged so that the axes are parallel. 24. The first and second optically uniaxial retardation plates, each of which is slow in phase with respect to the absorption axis of an adjacent one of the first and second polarization plates. 23. The liquid crystal display device according to claim 22, wherein the liquid crystal display device is arranged so that axes are orthogonal to each other. 25. The optical device according to claim 22, wherein the first and second optically uniaxial retardation plates have an in-plane retardation of 300 nm or less. Liquid crystal display device. 26. The liquid crystal display device according to claim 25, wherein the first and second optically uniaxial retardation plates are made of a resin having a norbornene structure in a main chain. 27. A liquid crystal panel, comprising: the first and second substrates together with the liquid crystal layer interposed therebetween; and the liquid crystal display further comprises a first polarizing plate having a first absorption axis. And a second polarizing plate having a second absorption axis, and the first absorption axis and the second absorption axis are orthogonal to each other on a first side and a second opposite side of the liquid crystal panel, respectively. The liquid crystal display device further comprises a first retardation plate having a first slow axis and a second retardation plate having a second slow axis, the liquid crystal panel and the second retardation plate having a second slow axis. The first retardation plate is located closer to the liquid crystal panel than the second retardation plate between the second retardation plate and the second polarizing plate, and the direction of the first slow axis is the second retardation plate. 8. The liquid crystal according to claim 7, wherein the second polarizer is disposed so as to be substantially orthogonal to the direction of the second absorption axis. Display device.