JPH05107534A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display element whose visual angle characteristic is improved, whose visual angle characteristic is freely controlled, and which is excellent in visibility. CONSTITUTION:This liquid crystal display element is provided wit a liquid crystal cell 3 for display where nematic liquid crystal composition is interposed and held between two substrates respectively having electrodes and which is driven by a voltage impressing means, and one or more liquid crystal cells 3 for optical compensation arranged adjacently to the cell 3 between two polarizing plates 1 and 4. The layer for optical compensation of the cell 2 is twisted and oriented at a screw axis nearly parallel with the normal of the substrate of the cell 3, and the voltage is impressed thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which the viewing angle dependence such as contrast ratio and display color is controlled.

[0002]

2. Description of the Related Art In recent years, liquid crystal display elements, which have the great advantages of thinness, light weight, and low power consumption, have been actively used as display devices for personal OA equipment such as Japanese word processors and desktop personal computers. Most of liquid crystal display elements (hereinafter abbreviated as LCD) use twisted nematic liquid crystal, and the display system can be roughly classified into two systems of an optical rotation mode and a birefringence mode.

The LCD of the optical rotation mode is, for example, a twisted nematic (TN) having a molecular arrangement twisted by 90 °.
Since it is a liquid crystal display, it displays black and white in principle, has a high contrast ratio and good gradation display, and has a high response speed (tens of milliseconds), so it is used for clocks, calculators, simple matrix drives, and switching elements. LCD with full color display (TFT-L
It is applied to CDs and MIM-LCDs (TN method).

On the other hand, a birefringence mode display type LCD
Is a super twist (ST) type liquid crystal having a molecular arrangement twisted by 90 ° or more, and has steep electro-optical characteristics. Therefore, even if there is no switching element (thin film transistor or diode) for each pixel, a simple matrix shape is used. Even with the electrode structure, a large capacity display can be easily obtained by time-division driving.
However, in this ST method, since the birefringence effect is used, the display colors are so-called yellow mode display of yellow and dark blue, or so-called blue mode display of white and blue due to light interference, and black and white display. Color display was impossible.

As a means for eliminating such coloring of the display, it is possible to realize a black and white display by disposing a second liquid crystal cell which is twisted in the opposite direction between the polarizing plate and the liquid crystal cell, as disclosed in Japanese Patent Publication No. 63-53528. Is disclosed in. The principle of black and white is that the light of the ordinary light component and the extraordinary light component, which are elliptically polarized in the display liquid crystal cell in which the liquid crystal molecules are arranged in a twisted arrangement, are exchanged with each other by the second liquid crystal cell which is the optical compensation plate. Elliptically polarized light is converted into linearly polarized light. As a result, coloring due to light interference is eliminated, and black and white display can be realized.

In order to convert the elliptically polarized light into the linearly polarized light as described above, the retardation value of the optical compensator is almost the same as that of the display liquid crystal cell, and the twist directions are opposite to each other. The arrangement is such that the alignment directions of the liquid crystal molecules closest to each other are orthogonal to each other. But,
In such an LCD, the display color is colored at an oblique angle deviating from the normal to the display surface, and black and white display cannot be obtained.

However, the liquid crystal display element utilizing the birefringence mode or the optical rotation mode has the viewing angle dependency that the display color and the contrast ratio change depending on the viewing angle and the azimuth, and the display performance of the cathode ray tube (CRT). It's too late to completely exceed.

For example, FIG. 20 shows the measurement results of the equal contrast ratio-azimuth angle characteristics of a TN type liquid crystal display element.
Here, the equal contrast ratio-azimuth characteristic indicates the viewing angle characteristic of the liquid crystal display element, and the point of observing the liquid crystal display element is defined by the azimuth angle Φ and the viewing angle θ as shown in FIG. It is the one shown in polar coordinates as shown in FIG. 20, which is obtained by measuring the vision showing a certain contrast ratio when the azimuth is changed.
Therefore, the viewing angle θ is large in the azimuth with a high contrast ratio, and it is desired that the vision is large in any azimuth angle as an ideal liquid crystal display element.

As can be seen from the measurement results of FIG. 20, the orientation directions of the upper and lower substrates are indicated by arrows in the drawing of FIG.
Is the orientation of the upper substrate, 14 is the orientation of the lower substrate), and when the tilting direction of the liquid crystal molecules near the center of the liquid crystal cell is 90 °, 90 °, 210 °, 330 °
The viewing angle is widest in the azimuth, and the 45 ° and 135 ° azimuths are narrow. The tilt direction of the liquid crystal molecules near the center of the liquid crystal cell depends on the tilt direction of the liquid crystal molecules on the upper and lower substrate surfaces,
When the pretilt angles (angles formed by the liquid crystal molecules and the substrates) on the upper and lower substrates are the same, the directions are almost in the middle of the tilt directions of the upper and lower substrate surfaces. When the polarizing plates are placed on the upper and lower substrates in such an alignment state and the absorption axes of the polarizing plates are aligned with the alignment directions of the respective substrates, the contrast ratio (luminance in bright state / luminance in dark state) The direction in which) is the highest almost coincides with the direction in which the liquid crystal molecules in the vicinity of the center of the liquid crystal cell are inclined.

As described above, at present, the liquid crystal display element does not have a characteristic such as a cathode ray tube (CRT) that shows a substantially uniform contrast ratio from any direction, but a viewing angle
The contrast ratio changes greatly depending on the azimuth. That is, since the liquid crystal display element has a viewing angle characteristic, it is necessary to expand the viewing angle characteristic of the liquid crystal display element or to design the viewing angle characteristic in accordance with the specifications depending on the application of the liquid crystal display element. On the other hand, for a liquid crystal display device having a structure in which a nematic liquid crystal cell in which a nematic liquid crystal having a negative dielectric anisotropy is vertically aligned is sandwiched between polarizing plates, an attempt to improve the viewing angle by sandwiching a cholesteric liquid crystal between the nematic liquid crystal cell and the polarizing plate has been made. It is described in JP-A-3-67219.

In this case, however, a nematic liquid crystal cell in which a nematic liquid crystal having a negative dielectric anisotropy is vertically aligned does not cause a problem of alignment technology, a response speed of a liquid crystal material, or a liquid crystal specific resistance. The TN liquid crystal or the ST liquid crystal described above is preferable as the nematic liquid crystal which is not suitable for use in the active matrix drive liquid crystal display. Further, the cholesteric liquid crystal for optical compensation does not apply a voltage, its alignment state is fixed, and the viewing angle cannot be positively controlled. As described above, the present technology has a practical problem.

On the other hand, for color display, a cholesteric liquid crystal cell showing a certain hue utilizing selective scattering when no voltage is applied is arranged between the polarizing plate and the nematic liquid crystal cell,
It is possible to switch to a two-color display mode of a specific hue and its complementary color or a monochrome display mode by combining the presence or absence of voltage application to the cholesteric liquid crystal cell and the nematic liquid crystal cell Mol. Cryst. Liq. Cryst. ，
1977, VOL. 39, PP. 127-138.

[0013]

As described above, currently, the liquid crystal display element does not have a characteristic that a substantially uniform contrast ratio is seen from every direction like a cathode ray tube (CRT), but the contrast ratio depends on the viewing angle and direction. Changes greatly. That is, the liquid crystal display element has a viewing angle characteristic, and therefore, the liquid crystal display element has a narrow viewing angle characteristic and is good only in a limited direction. Further, in the related art, the viewing angle cannot be positively controlled by a control signal such as a voltage from the outside, and for example, the viewing angle characteristic is fixed.

The present invention solves the above inconvenience.

[0015]

DISCLOSURE OF THE INVENTION The present invention provides a display liquid crystal cell in which a nematic liquid crystal layer is sandwiched between two substrates each having an electrode between two polarizing plates and which is driven by voltage application means. In a liquid crystal display device including one or more optical compensation liquid crystal layers arranged adjacent to a display liquid crystal cell, at least one of the optical compensation liquid crystal layers is substantially parallel to a substrate normal line of the display liquid crystal cell. A liquid crystal display element is characterized in that it is twisted and oriented along a spiral axis and has a voltage applying means.

[0016]

The liquid crystal display device has a pretilt angle for manufacturing and stabilizing the alignment, which affects the viewing angle characteristics. When a voltage above the threshold value is applied to the liquid crystal cell, most of the liquid crystal molecules in the liquid crystal cell are tilted with respect to the substrate surface, except near the substrate surface. FIG. 3 is a schematic view showing such an alignment state of the liquid crystal with a three-dimensional index ellipsoid. The birefringence phenomenon is a phenomenon relating to the difference in the refractive index in the two-dimensional plane when the refractive index ellipsoid 5 is viewed from a certain direction, and therefore when viewed from the z direction (5.1) (that is, the liquid crystal cell is The refractive index body (5.2) in the two-dimensional plane when viewed from the front is an ellipse, and the refractive index body (5. 5) when viewed from the major axis direction (5.3) of the three-dimensional refractive index ellipsoid. Different from 4). Therefore, the place where the contrast ratio becomes maximum is where the refractive index body in the two-dimensional plane becomes completely circular, which is in the major axis direction of the three-dimensional refractive index ellipsoid. Therefore, by changing the shape of the three-dimensional index ellipsoid of the liquid crystal display element by the index ellipsoid for optical compensation,
It is possible to improve the viewing angle characteristic in the azimuth where the contrast ratio is maximized. The refractive index ellipsoid for optical compensation is set to a shape corresponding to the shape of the three-dimensional refractive index ellipsoid of the liquid crystal cell, and as shown in FIG. By arranging the axis (6.1) substantially parallel to the long axis of the three-dimensional index ellipsoid 5 of the liquid crystal cell, the viewing angle characteristics in the viewing angle direction, that is, the direction where the viewing angle is large can be easily expanded.

Such an index ellipsoid for optical compensation is
It has a characteristic of being optically negative and having an optical axis oblique to the display surface. As an optically negative optical anisotropy,
A cholesteric liquid crystal cell can be given. Cholesteric liquid crystals are liquid crystal molecules that are arranged in a spiral twist,
Cholesteric liquid crystals show optically negative optical anisotropy due to a helical twist arrangement, whereas general liquid crystals have positive optical anisotropy. In this case, the cholesteric liquid crystal layer itself does not have optical activity. By combining such a cholesteric liquid crystal with a driving liquid crystal cell, the shape of the index ellipsoid can be compensated, and as a result, the visual field characteristics can be compensated and the viewing angle can be expanded.

Further, in the case of a liquid crystal having a pitch smaller than that of the cholesteric liquid crystal, it cannot be said that the optical axis of the cell is perpendicular to the substrate normal and does not have optically negative uniaxial anisotropy, and thus has optical rotatory power. In this case, although the characteristics are slightly different, the visual field characteristics can be similarly changed and improved.

In the liquid crystal cell for driving the display, all the liquid crystal molecules are not aligned in the direction of the substrate line when a voltage is applied, but there is a portion where they are not aligned due to the alignment force of the substrate, and twistability remains. However, the resulting elliptically polarized light can be compensated by the compensating liquid crystal layer whose pitch is not too small.

The viewing angle can be improved by the above phenomenon when the display liquid crystal is various liquid crystal such as TN liquid crystal and ST liquid crystal.

As an example, a TN type liquid crystal cell is used as a driving liquid crystal cell, a birefringence Δn of a liquid crystal material is 0.044 as an optically compensating liquid crystal layer, and a twisting rotational speed of liquid crystal at a distance between two substrates ( d / P, d: substrate distance, P: pitch)
= 16.25 rotations (counterclockwise), the distance (cell thickness) d between the two substrates is 3.5 μm, 7.5 μm, 10.0 μ
m, 15.0 μm was changed to create an optical compensation cell, the display TN cell and these optical compensation cells were superposed, and the isocontrast curve when these were sandwiched between two polarizing plates was d. FIG. 5 with 3.5 μm to FIG. 8 with d of 15.0 μm are shown correspondingly. 20 shows the isocontrast curve of the conventional device without the optical compensation cell. From these, it can be seen that the viewing angle range changes as the cell thickness of the optical compensation cell changes.

Similarly, a TN type liquid crystal cell is used as the driving liquid crystal cell, and the birefringence index Δn of the liquid crystal material is 0.044, the cell thickness is 10 μm, and the liquid crystal at the distance between the two substrates is used as the optical compensation liquid crystal layer. Twisting rotation speed (d / P, where d: distance between substrates, P: pitch) is 2.75 rotations (counterclockwise),
Create optical compensation cells that are changed to 1.75 rotations (counterclockwise), 2.75 rotations (clockwise) and 1.75 rotations (clockwise), and superimpose these display compensation TN cells on these optical compensation cells. Corresponding isocontrast curves when these are sandwiched between two polarizing plates are shown in FIGS. 9 to 12, respectively. From these, it can be seen that the viewing angle range changes as the d / P of the optical compensation cell changes. In particular, it can be seen that the viewing angle moves upward in the counterclockwise cell, and the viewing angle moves downward in the clockwise cell.

In the present invention, as the liquid crystal layer for optical compensation, there is provided at least one liquid crystal layer for optical compensation which is twisted and aligned with a spiral axis substantially parallel to the substrate normal line of the driving liquid crystal cell, It has means for applying a voltage to each of the optical compensation liquid crystal layers.

When a voltage is applied to the optical compensating cell having the optical compensating liquid crystal layer, the liquid crystal molecule orientation is changed, the twist is released, and the optical compensating effect as described above is changed. This corresponds to a change in cell thickness of the optical compensation cell, a change in rotation speed d / P, or a change in Δn of the liquid crystal material.

For example, as the optically-compensatory liquid crystal layer, the birefringence Δn of the liquid crystal material is 0.044, the cell thickness is 10 μm, and d / P.
Consider a case where a cell of 2.75 rotations in the counterclockwise direction and a cell of one rotation in the clockwise direction are used, and these cells and the TN cell are overlapped and sandwiched between two polarizing plates. When a voltage is not applied to any of these two optical compensation cells, the characteristics are equivalent to and similar to the case of using the counterclockwise 1.75 rotation cell.
Further, when the voltage is applied to the cell of one clockwise rotation to release the twist, it corresponds to the case of using the cell of 2.75 counterclockwise rotation, and conversely, the cell of 2.75 rotation counterclockwise. The case where the voltage is applied to and the twist is released corresponds to the case where a cell that makes one clockwise rotation is used. Therefore, the viewing angle range can be freely controlled by applying a voltage to the optical compensation cell.

The TN type liquid crystal has been described above as the liquid crystal for display. However, in addition to the ST type liquid crystal, a nematic liquid crystal cell in which a nematic liquid crystal having a negative dielectric anisotropy is vertically aligned is also used as the display liquid crystal. Similarly, it is needless to say that the viewing angle characteristics can be controlled by controlling the orientation of the compensating liquid crystal layer with a voltage.

With respect to the structure of the optical compensation cell, the viewing angle can be controlled by applying a voltage to itself with a single cell, or with a plurality of cells in the same rotation direction or in the opposite rotation direction. In this case, the number of rotations in one cell can be freely set such as when the number of rotations is larger than 1 or smaller than 1. Further, in the case of stacking a plurality of liquid crystal layers for compensation, for example, in the adjacent liquid crystal layers, if the liquid crystal alignment direction is the same on the surface, or conversely orthogonal, the resulting optical compensation effect is different, Since the characteristics of the viewing angle are also different, they can be freely set as needed.

In the present invention, various optical compensation liquid crystal layers are not used only in the direction of widening the viewing angle,
Depending on the application, if a limited narrow viewing angle is desired, the optical design may be designed so as to narrow the viewing angle.

[0029]

EXAMPLES Examples of the liquid crystal display device of the present invention will be described in detail below.

(Embodiment 1) FIGS. 1 and 2 show the cell structure in this embodiment. The liquid crystal display element 10 has a structure in which two polarizing plates 1 and 4 and an optical compensation liquid crystal cell 2 and a display liquid crystal cell 3 are sandwiched therebetween. The polarizing plate 1 is formed by attaching the polarizing film 1b to the inside of the transparent substrate 1a, and the polarizing plate 4 is also formed by attaching the polarizing film 4b to the transparent substrate 4a. Also, the absorption axes (1.1) of these polarizing plates 1 and 4
(4.1) are arranged so as to be orthogonal to each other.

The optical compensating liquid crystal cell 2 is disposed between the polarizing plates 1 and 4, and is adjacent to the display liquid crystal cell 3 so as to face or face each other. Cell 2 is transparent electrode 2
The liquid crystal layer 2e is formed between the transparent substrates 2a and 2b on which c and 2d are formed.
It has a liquid crystal cell structure in which is interposed. A normal nematic liquid crystal was used for the liquid crystal layer 2e. The electrodes 2c and 2d of the liquid crystal cell 2 are connected to the driving power supply 2f.

The display liquid crystal cell 3 is an optical compensation liquid crystal cell 2.
And the polarizing plate 4. Upper substrate 3a and lower substrate 3
b and transparent electrodes 3c and 3d, respectively, are formed and connected to the driving power source 3f.

A twisted nematic liquid crystal layer 3e is introduced between the substrates 3a and 3b with a twist angle of 90 °, and a driving power source 3f
The state changes according to the applied voltage from the.

The optical axis of the liquid crystal of the display liquid crystal cell 3 is twisted counterclockwise from the upper substrate 3a to the lower substrate 3b (left twist). (3.1) and (3.2) are rubbing axes of the upper and lower substrates, respectively, which are orthogonal to each other. The retardation value of the liquid crystal cell 3 is 450 nm.

The optical compensating liquid crystal cell 2 is a liquid crystal cell having a left twist (2.75 rotations) of 990 ° about a spiral axis parallel to the normal line (Z axis) of the substrates 3a and 3b of the display liquid crystal cell. (2.1) and (2.2) are rubbing axes of the upper and lower substrates 2a and 2b, respectively, which are orthogonal to each other.

The absorption axis (1.1) of the polarizing plate 1 and the rubbing axes (2.2) and (3.2) of the lower substrate are parallel to each other, and the polarizing plate 4
Absorption axis (4.1) and the rubbing axis (2.
1) and (3.1) are parallel.

The liquid crystal display element of this embodiment is applied to the display liquid crystal cell 3 under the following conditions: bright state: 1 V is applied between the driving power source 3f and the liquid crystal cell electrode, and dark state: 5 V is applied between the driving power source 3f and the liquid crystal cell electrode. Then, the equal contrast ratio-azimuth characteristic was measured.
In this case, FIG. 13 shows the equal contrast ratio-azimuth characteristics when no voltage is applied to the liquid crystal cell for optical compensation. The figure shows that the viewing angle characteristics in the 45 ° and 135 ° azimuths are good. On the other hand, FIG. 14 shows an equal contrast ratio-azimuth characteristic when a voltage of 5 V is applied to the optical compensation liquid crystal cell 2. In this case, the viewing angle characteristics in the 90 °, 210 °, and 330 ° azimuths are good. In this way, the viewing angle can be controlled by the voltage applied to the liquid crystal cell for optical compensation.

(Example 2) In Example 1, in addition to the optical compensation liquid crystal cell 2, that is, the first optical compensation liquid crystal cell, a second optical compensation liquid crystal cell (not shown) was added to the polarizing plate 1.
Sandwiched between. The second liquid crystal cell for optical compensation is clockwise 3
Other characteristics were the same as those of the first optical compensation liquid crystal cell 2 at 60 °. The orientation directions of liquid crystal molecules on the surfaces of the first optical compensation liquid crystal cell 2 and the second optical compensation liquid crystal cell adjacent to each other were parallel to each other.

The liquid crystal display device of this structure is used as a display liquid crystal cell 3
Then, the equal contrast ratio-azimuth characteristics were measured under the following conditions: bright state: 1 V applied between the driving power source 3f and the liquid crystal cell electrode, and dark state: 5 V applied between the driving power source 3f and the liquid crystal cell electrode. In this case, the isocontrast ratio-azimuth characteristics when no voltage is applied to the first and second optical compensation liquid crystal cells are shown in FIG.
5 shows.

FIG. 16 shows the iso-contrast ratio-azimuth characteristics when 5 V is applied to the second optical compensation liquid crystal without applying a voltage to the first optical compensation liquid crystal cell 2.

FIG. 17 shows the isocontrast ratio-azimuth characteristics when 5 V is applied to the first optical compensation liquid crystal cell without applying a voltage to the second optical compensation liquid crystal cell.

In addition, the first optical compensation liquid crystal cell has 3
FIG. 18 shows the contrast ratio-azimuth characteristics when V and 5 V are applied to the second optical compensation liquid crystal cell. In this way, the viewing angle characteristics can be controlled by the voltages applied to the first and second liquid crystal cells for optical compensation.

The present invention has been described above with reference to the examples. However, without being restricted to the constitution of the examples, for example, a film having uniaxial or biaxial optical anisotropy or a film having twisted optical properties is used as an optical compensation layer. In addition to the above structure, a layer may be laminated, and the liquid crystal layer for optical compensation may be a polymer liquid crystal.

As a driving cell for displaying,
In addition to TN type liquid crystal and super twist type liquid crystal, various types of liquid crystal such as vertically aligned cells of liquid crystal with negative dielectric anisotropy, ferroelectric liquid crystal, etc. can be used. For example, an active matrix driven liquid crystal display device using a TFT or the like, and various devices such as one using a color filter or a projection type liquid crystal display device can be used depending on the case.

[0045]

According to the present invention, it is possible to provide a high-quality liquid crystal display device which has improved viewing angle characteristics of the liquid crystal display element and can be freely controlled in viewing angle characteristics and has excellent visibility.

Needless to say, even if the present invention is applied to an active matrix liquid crystal display device using a 3-terminal or 2-terminal element such as TFT or MIM, excellent effects can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the configuration of the element of the embodiment shown in FIG.

FIG. 3 is a diagram showing a three-dimensional refractive index ellipsoid with liquid crystal molecules standing.

FIG. 4 is a view for explaining a refractive index ellipsoid for optically compensating the refractive index ellipsoid of FIG.

FIG. 5 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 6 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 7 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 8 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 9 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 10 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 11 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 12 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the present invention.

FIG. 13 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the first embodiment of the present invention.

FIG. 14 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the first embodiment of the present invention.

FIG. 15 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the second embodiment of the present invention.

FIG. 16 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the second embodiment of the present invention.

FIG. 17 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the second embodiment of the present invention.

FIG. 18 is an equal contrast ratio-azimuth characteristic diagram for explaining the function and effect of the second embodiment of the present invention.

FIG. 19 is a view for explaining that an observation point is defined by an azimuth angle Φ and a viewing angle θ, and an equal contrast ratio-azimuth characteristic is obtained by polar coordinates.

FIG. 20 is an equal contrast ratio-azimuth characteristic diagram for explaining the conventional operation and effect.

[Explanation of symbols]

 1, 4 ... Polarizing plate 2 ... Optical compensation liquid crystal cell 3 ... Display liquid crystal cell

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junko Hirata 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock company Toshiba Yokohama office

Claims (1)

[Claims] 1. A display liquid crystal cell driven by a voltage applying means by sandwiching a nematic liquid crystal layer between two substrates each having an electrode between two polarizing plates, and adjacent to the display liquid crystal cell. In a liquid crystal display device comprising one or more optical compensation liquid crystal layers arranged, at least one of the optical compensation liquid crystal layers is twisted and aligned with a spiral axis substantially parallel to a substrate normal line of the display liquid crystal cell. And a liquid crystal display device comprising a voltage applying unit.