KR19990004389A - Wide viewing angle liquid crystal display using compensation film - Google Patents

Abstract

Using a vertically aligned liquid crystal and using a plate, c plate, and biaxial compensation film as appropriately combined, the slow axis with the highest refractive index of the a plate or biaxial compensation film coincides with the transmission axis of the adjacent polarizing plate. When the refractive index in the x, y, z-axis direction of the molecules constituting the compensation film is nx, ny, nz, respectively, the a plate compensation film, the c plate compensation film and / or the biaxial compensation film The difference between the sum of the retardation values (nx-nz) * d and the retardation value of the polarizing plate and the retardation value due to birefringence of the liquid crystal cell is 15% or less of the retardation value of the birefringence of the liquid crystal cell, and a plate compensation film or biaxial property By adding the delay value (nx-ny) * d of the compensation film to 0 to 100 nm, a liquid crystal display device having a high contrast ratio and an extended viewing angle can be obtained.

Description

Wide viewing angle liquid crystal display using compensation film

The present invention relates to a liquid crystal display device, and more particularly, to a wide viewing angle liquid crystal display device using a vertical alignment and a compensation film.

Liquid crystals have birefringence with different refractive indices in the long axis and short axis of the molecule. The birefringence causes a difference in the refractive index of light depending on the position at which the liquid crystal display device is viewed. There is a difference in the rate of change of state, so the amount of light and color characteristics when viewed from a position away from the front are different from those seen from the front. Accordingly, in the liquid crystal display having a twisted nematic structure, a change in contrast ratio, color shift, gray inversion, etc. may occur according to a viewing angle.

In order to compensate for the phase difference generated in the liquid crystal cell, a technology of a TN LCD using a phase difference compensation film has been developed. This solves the viewing angle problem by compensating for the change of the phase of light inside the liquid crystal in the opposite direction in the retardation film. However, even with this method, the TN LCD using a negative phase difference compensation film can only improve the gradation characteristics when viewed in a direction that forms an angle of 45 degrees with the transmission axis of the polarizing plate. The problem still exists. Meanwhile, vertically aligned TN-LCDs (VATN-LCDs) using liquid crystals having negative dielectric anisotropy different from conventional TN-LCDs have been developed. This device can be manufactured with a simpler process and less cost than the conventional TN-LCD, and has many advantages over the conventional TN-LCD, such as high contrast ratio, low threshold voltage and fast response time. .

In the case of TN-LCD, the arrangement of the liquid crystal molecules in a state in which no voltage is applied is in a spirally twisted state in which the long axis of the liquid crystal molecules is parallel to the substrate, and when the voltage is applied, the long axis of the liquid crystal molecules is perpendicular to the substrate. Will change. In contrast, the initial state of the VATN-LCD has an arrangement state of liquid crystal molecules similar to that of the TN-LCD, and is changed into a twisted arrangement when voltage is applied.

In the case of VATN-LCD, the liquid crystal molecules are vertically arranged in the off state, and there is no retardation of light when viewed in the same direction as the alignment direction of the liquid crystal molecules. Thus, when viewed from this angle, a very high contrast ratio can be maintained. However, when viewed from an angle different from the direction in which the liquid crystal molecules are arranged, the contrast ratio is low due to the delay of light due to the birefringence of the liquid crystal, and the contrast ratio is very low, especially when viewed in a direction of 45 degrees with the transmission axis of the polarizer. . The viewing angle characteristic of a typical VATN-LCD is as shown in FIG. 1, and FIG. 2 shows a three-dimensional luminance map of a typical VATN-LCD.

A cell in which liquid crystal molecules are arranged vertically has a plate-like property with positive birefringence. Therefore, this birefringence can be canceled by using a c plate compensation film having negative birefringence, and the optimum value of the retardation value of the c plate compensation film used at this time is almost the same as the retardation value caused by the birefringence of the liquid crystal cell. Would be desirable. 3 to 4 show the viewing angle characteristics and three-dimensional luminance of the VATN using the c plate compensation film. Compared with no compensation film, the viewing angle characteristic is much improved.

However, it can be seen that the contrast ratio is still low even when compensated using the c plate compensation film when viewed in a direction forming an angle of 45 degrees with the polarizing plate of the polarizing plate, because the inherent light leakage phenomenon by the polarizing plate occurs.

An object of the present invention is to provide a liquid crystal display having a high contrast ratio and an extended viewing angle using a VATN-LCD.

1 is a graph showing viewing angle characteristics of a vertically oriented twisted nematic liquid crystal display (VATN-LCD) without using a compensation film;

Figure 2 is a graph showing the three-dimensional brightness of the VATN-LCD without using a compensation film,

3 is a graph showing the viewing angle characteristics of the VATN-LCD using a c plate compensation film,

4 is a graph showing three-dimensional luminance of the VATN-LCD using a c plate compensation film,

5A to 14 are exploded perspective views showing the structure of the VATN-LCD according to the first to sixteenth embodiments of the present invention, respectively;

15 is a graph showing a contrast ratio of a VATN-LCD according to a tenth embodiment of the present invention,

16 is a graph showing a contrast ratio of a VATN-LCD according to an eleventh embodiment of the present invention,

17 is a graph illustrating a contrast ratio of a VATN-LCD according to a thirteenth embodiment of the present invention.

18 is a graph illustrating viewing angle characteristics of a VATN-LCD according to an eleventh embodiment of the present invention;

19 is a graph illustrating viewing angle characteristics of a VATN-LCD according to a thirteenth embodiment of the present invention;

20 is a graph showing three-dimensional brightness of a VATN-LCD according to an eleventh embodiment of the present invention,

21 is a graph showing three-dimensional brightness of a VATN-LCD according to a thirteenth embodiment of the present invention.

22A to 22C are graphs illustrating the eight-gradation display performance of the VATN-LCD according to the thirteenth embodiment of the present invention.

23A to 23D are graphs showing the eight-gradation display performance when the thirteenth embodiment of the present invention is applied to a two-region VATN-LCD.

24 is a graph showing the viewing angle characteristics when the tenth embodiment of the present invention is applied to a two-region VATN-LCD.

Fig. 25 is a graph showing viewing angle characteristics when the eleventh embodiment of the present invention is applied to a two-region VATN-LCD.

In order to solve this problem, in the present invention, a vertically aligned liquid crystal in which a liquid crystal material having negative dielectric anisotropy is enclosed is used, and a plate compensation film, c plate compensation film, and biaxial compensation film are appropriately combined and disposed.

In addition, the slow axis of the refractive index of the a-plate compensation film or the biaxial compensation film used at this time is parallel or perpendicular to the transmission axis of the adjacent polarizing plate.

Then, the delay value (nx-nz) * d of the a plate compensation film used at this time, the delay value (nx-nz) * d of the c plate compensation film and the delay value (nx-nz) * d of the biaxial compensation film And the difference between the sum of the delay values by the polarizing plates and the delay values due to the birefringence of the liquid crystal cell to be within 15% of the delay value due to the birefringence of the liquid crystal cell, and a delay value (nx-ny) * d of the plate compensation film It is preferable that the sum of the retardation values (nx-ny) * d of the biaxial compensation film is from 0 to 100 nm. Here, the z-axis is in the direction perpendicular to the surface of the liquid crystal cell, the x-axis in the direction of the liquid crystal cell and having the largest refractive index in the a plate compensating film or the biaxial compensating film, and in the surface of the liquid crystal cell When the direction perpendicular to the y axis is set, nx, ny, and nz represent refractive indexes in the x, y, and z axis directions of the compensation film, respectively, and d is the cell gap of the liquid crystal cell.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 5A-14 illustrate various embodiments of the present invention.

The structure of the liquid crystal display according to the first exemplary embodiment of the present invention is shown in FIG. 5A. The rear polarizer 10 is attached to the rear of the liquid crystal cell 50 into which the liquid crystal material having negative dielectric anisotropy is injected, and on the opposite side, a plate compensation film between the liquid crystal cell 50 and the front polarizer 11. 20 and c plate compensation film 30 are sandwiched. The buffing direction of the alignment film (not shown) applied to the entire surface of the liquid crystal cell 50 is from the lower left to the upper right, and arrows indicated by solid lines in the drawing indicate this direction. On the contrary, the buffing direction of the alignment layer applied to the rear surface of the liquid crystal cell 50 is directed from the upper left to the lower right, and is indicated by an arrow indicated by a dotted line on the drawing. In this embodiment, the transmission axis of the polarizing plate has the same e mode as the buffing direction of the adjacent alignment film.

The z-axis is perpendicular to the surface of the liquid crystal display, and the x-axis and y-axis are on the same plane as the surface of the liquid crystal display. When nx, ny and nz are respectively, a plate compensation film says the case where nxny = nz and c plate compensation film says the case where nx = nynz. a The x axis of the plate compensating film 20, i.e., the slowest axis of refraction, should be arranged to be parallel or perpendicular to the transmission axis of the adjacent polarizer, otherwise light leakage may occur and This is because there is a problem that the contrast ratio falls. In the case of the liquid crystal display shown in FIG. 5A, the x-axis of the a plate compensating film 20 is disposed in a direction connecting the lower left and the upper right, and is disposed to be parallel to the transmission axis of the front polarizing plate 11. In the figure, both arrows shown in a plate compensation film 20 indicate the direction of the x-axis.

As shown in FIG. 5B, the second embodiment of the present invention reverses the order of the a plate compensating film 20 and the c plate compensating film 30 from the first embodiment. The rear polarizer 10 is attached, the a plate compensation film 20 is attached to the liquid crystal cell 50 on the opposite side, and the c plate compensation film 30 and the front polarizer 11 on the outer side thereof. Attached. The buffing direction of the alignment layer, the transmission axis direction of the polarizing plate, and the x axis direction of the a plate compensating film 20 are the same as in the first embodiment.

In the third and fourth embodiments of the present invention, as shown in FIGS. 5C and 5D, respectively, a plate compensating film 20 and c plate compensating film 30 are disposed between the rear polarizer 10 and the liquid crystal cell 50. It is attached. In the third exemplary embodiment, the c plate compensation film 30 is attached to the rear surface of the liquid crystal cell 50, and the a plate compensation film 20 and the rear polarizer 10 are attached to the outer surface thereof. The front polarizing plate 11 is attached to the front surface of the liquid crystal cell 50 (FIG. 5C). The fourth embodiment changes the positions of the a plate compensating film and the c plate compensating film of the third embodiment (FIG. 5D). The buffing direction of the alignment layer and the transmission axis direction of the polarizing plate are the same as in the first embodiment. At this time, the x-axis of the a-plate compensation film 20 coincides with the transmission axis of the rear polarizing plate 10 which is an adjacent polarizing plate.

6A to 6D illustrate a case in which the o mode is a vertical transmission axis of the polarizing plate adjacent to the buffing direction of the alignment layer of the liquid crystal cell as the fifth to eighth embodiments of the present invention. The arrangement of the liquid crystal cell 50, the polarizing plates 10 and 11, the a plate compensating film 20, and the c plate compensating film 30 are the same as those of FIGS. 5A to 5D, respectively, but the polarizing plates adjacent to the buffing direction of the alignment layer are disposed. The difference is that the transmission axis is arranged perpendicularly.

7 shows a c plate compensation film 31 between the liquid crystal cell 50 and the rear polarizer 10 in which the compensation film is not inserted in the same structure as the first embodiment of the present invention shown in FIG. 5A. The ninth embodiment of the present invention is further illustrated, and the tenth embodiment of the present invention has a c plate compensation film 31 and a rear polarizer 10 having the same structure as that of the ninth embodiment as shown in FIG. 8. The a plate compensating film 21 is added in between.

The liquid crystal display according to the eleventh exemplary embodiment of the present invention is illustrated in FIG. 9. The rear polarizer 10 is attached to the rear side of the liquid crystal cell 50 injecting the liquid crystal material having negative dielectric anisotropy, and the biaxial compensation film is disposed between the liquid crystal cell 50 and the front polarizer 11 on the opposite side. 40 is fitted. Biaxial compensation film refers to a compensation film having a structure of nxnynz. As in the previous embodiments, the x-axis of the biaxial compensation film should be arranged to be parallel or perpendicular to the transmission axis of the adjacent polarizer, and both the e mode and the o mode are possible.

In the twelfth embodiment of the present invention, the biaxial compensation film 40 is attached between the rear polarizer 10 and the liquid crystal cell 50 as shown in FIG. 10, and in the thirteenth embodiment, as shown in FIG. The compensation films 40 and 41 are attached to both the front polarizer 11 and the liquid crystal cell 50 and between the rear polarizer 10 and the liquid crystal cell 50.

A liquid crystal display according to a fourteenth embodiment of the present invention is shown in FIG. 12. The rear polarizer 10 is attached to the rear side of the liquid crystal cell 50 injecting the liquid crystal material having negative dielectric anisotropy, and the biaxial compensation film is disposed between the liquid crystal cell 50 and the front polarizer 11 on the opposite side. 40 and c plate compensation film 30 are sandwiched. The x-axis of the biaxial compensation film 40 is parallel to the transmission axis of the adjacent polarizing plate 11, and is shown in the case where it is applied to an e mode in which the buffing direction of the alignment film of the liquid crystal cell 50 and the transmission axis of the adjacent polarizing plate coincide. . The biaxial compensation film 40 and the c plate compensation film 30 may be attached in reverse order, or may be attached between the rear polarizer 10 and the liquid crystal cell 50. In addition, a fifteenth embodiment of the present invention further attaches a c plate compensation film 31 between the rear polarizer 10 and the liquid crystal cell 50 in addition to the front polarizer 11 and the liquid crystal cell 50. A sixteenth embodiment is shown in FIG. 14, in which two sheets of the c plate compensation film 31 and the biaxial compensation film 41 are added. The x-axis of the biaxial compensation film may be perpendicular to the transmission axis of the adjacent polarizing plate, or may be applied to the o mode in which the buffing direction and the transmission axis of the polarizing plate are vertical.

In the VATN liquid crystal display, the contrast ratio CR may be expressed as follows.

CR = (luminance) on / (luminance) off

That is, in the normally black mode, the contrast ratio is obtained by dividing the luminance on of a state where voltage is applied to the liquid crystal display by the luminance off of an off state. Value. Therefore, the contrast ratio can be greatly improved if the luminance off can be reduced. The viewing angle characteristics and gray scale display performance of the liquid crystal display according to the exemplary embodiment of the present invention are calculated by using an optical simulation program. The geometry and related parameters used in the simulations are shown in Table 1, assuming that the polarizer itself produces a delay of -60 nm.

Table 1 Parameters of TN Cells Used in Optical Simulation

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Elastic constant (pN) K ₁ 16.6

K ₂ 6.5

K ₃ 18.5

Relative permittivity ε _∥ 3.5

ε _⊥ 7.7

Refractive Index n _e 1.5584

n _o 1.4757

Pretilt angle ( ^o ) θ _p 89

Torsion angle ( ^o ) Φ _TN 90

Cell spacing (μm) d4.0

Cell spacing / pitch d / p0.1

Off state voltage (V) V _off 0

On state voltage (V) V _on 5

Buffing Direction Front 45 ^o or 225 ^o

Rear 315^oOr 135^o

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The retardation value of all retardation films (including the retardation of light by the polarizing plate), that is, the sum of (nx-nz) * d, should be approximately equal to the retardation value by the birefringence of the liquid crystal cell. In the case of the liquid crystal cell used in the simulation of the present invention, the delay value due to birefringence is about 320 nm. However, the delay value (nx-ny) * d must be optimized for each case.

FIG. 15 illustrates contrast ratio (nx-ny) * d when the liquid crystal display according to the tenth exemplary embodiment of the present invention shown in FIG. 8 is viewed from an angle of 60 degrees up, down, left, and right.

Referring to FIG. 8, when the structure of the liquid crystal display according to the tenth exemplary embodiment of the present invention is described in detail, the c plate compensation film 30 may be formed on the front surface of the liquid crystal cell 50 into which the liquid crystal material having negative dielectric anisotropy is injected. ) And a plate compensation film 20 are attached in turn, and then the front polarizer 11 is attached. The c plate compensation film 31 and the a plate compensation film 21 are sequentially attached to the rear surface of the liquid crystal cell 50, and the rear polarizer 10 is attached. The transmission axis of the polarizing plate is in the e mode that coincides with the buffing direction of the adjacent alignment film, and the x axes of the a-plate compensation films 20 and 21 coincide with the transmission axes of the adjacent polarizing plates, respectively.

The optimum value (nx-ny) * d of the retardation value of a plate compensating film is about 20 nm as shown in the graph of FIG. 15, and the contrast ratio seen from the upper 60 degree direction is about 140: 1.

FIG. 16 illustrates contrast ratio (nx-ny) * d when the liquid crystal display according to the eleventh embodiment of the present invention shown in FIG. 9 is viewed from an angle of 60 degrees up, down, left, and right. According to the graph of FIG. 16, the optimum value of (nx-ny) * d is about 50 nm.

When the biaxial compensation film is used as in the eleventh embodiment of the present invention, it can be seen that a better contrast ratio can be obtained than in the tenth embodiment. As shown in FIG. 16, a high contrast ratio of 175: 1 or more is seen when viewed from the upper 60 degree direction, and a contrast ratio of about 250: 1 and 175: 1 is obtained when viewed from the left and right 60 degree directions, respectively.

FIG. 17 illustrates a contrast ratio (nx-ny) * d when the liquid crystal display according to the thirteenth embodiment of the present invention shown in FIG. 11 is viewed from an angle of 60 degrees up, down, left, and right.

Referring to FIG. 11, the configuration of the liquid crystal display according to the thirteenth embodiment of the present invention will be described in detail. The biaxial compensation is performed on the front and rear surfaces of the liquid crystal cell 50 into which the liquid crystal material having negative dielectric anisotropy is injected. The films 40 and 41 are attached, and the front polarizing plate 11 and the rear polarizing plate 10 are attached to the compensation films 40 and 41, respectively. The transmission axis of the polarizing plates is in the e mode that coincides with the buffing direction of the adjacent alignment films, and the x-axis of the biaxial compensation films 40 and 41 corresponds to the transmission axes of the adjacent polarizing plates, respectively.

As shown in the graph of FIG. 17, the optimum value of (nx-ny) * d in the thirteenth embodiment of the present invention is about 40 nm, and this case also shows a good contrast ratio similar to that of the eleventh embodiment of the present invention. The contrast ratio in the upper 60 degree direction is about 200: 1, and the contrast ratio in the left and right 60 degree direction is 250: 1 or more.

In the tenth embodiment of the present invention, when the retardation values (nx-nz) * d of the c plate compensation films 30 and 31 are 100 nm, the retardation value of the a plate compensation film is 20 nm and the retardation value by the polarizing plate is Since it is 60 nm, the sum of all (nx-nz) * d is 360 nm, which is almost equal to the delay value due to birefringence of the liquid crystal cell.

In the eleventh embodiment of the present invention, when the retardation value (nx-nz) * d of the biaxial compensation film 40 is set to 200 nm, the sum of all (nx-nz) * d becomes 320 nm, which is birefringence of the liquid crystal cell. Match the delay value by.

In the thirteenth embodiment of the present invention, when the retardation values (nx-nz) * d of the biaxial compensation films 40 and 41 are 100 nm, the sum of all (nx-nz) * d is the same as in the eleventh embodiment. It becomes 320nm.

As described above, the delay value (nx-nz) * d is a good compensation result when the difference between the sum of the total delay values and the delay value due to the birefringence of the liquid crystal cell does not exceed 15% of the delay value due to the birefringence of the liquid crystal cell. have.

18 and 19 show viewing angle characteristics of the liquid crystal display using the compensation films according to the eleventh and thirteenth embodiments of the present invention, respectively. It can be seen that the viewing angle characteristic is remarkably improved compared to the case of not using the compensation film (FIG. 1) or using only the c plate compensation film (FIG. 2).

20 and 21 show three-dimensional luminance maps of the liquid crystal display using the compensation films according to the eleventh and thirteenth embodiments of the present invention, respectively. In the case of the vertically aligned TN liquid crystal without a compensation film, a unique light leakage exists when viewed at an angle of 45 degrees with respect to the polarization direction in the off state, and the light leakage is compensated by using a c plate compensation film. According to an exemplary embodiment of the present invention, which can be reduced to one third and compensated using a biaxial compensation film, light leakage caused by a polarizing plate can also be reduced, thereby obtaining an optimal black state. In this case, therefore, a very high contrast ratio can be obtained.

The eight-step gray scale display performance in the VATN liquid crystal calculated in the mode using the optimized biaxial compensation film according to the thirteenth embodiment of the present invention is shown in FIGS. 22A to 22C. FIG. 22A is a graph illustrating a change in luminance according to a viewing angle when viewed from a direction forming an angle of 45 degrees with a transmission axis of a polarizer, and FIG. 22B is a graph when viewed from a direction perpendicular to the transmission axis of a polarizer, and FIG. 22C is It is a graph when it sees from the direction parallel to the transmission axis of a polarizing plate. In this case, the contrast ratio was greatly improved, but the gray scale display performance did not bring much improvement.

When the same structure is applied to the two-area VATN, gray scale display performance is greatly improved. 23A to 23D show the gray scale display performance when the structure according to the thirteenth embodiment of the present invention is applied to a two-region VATN. FIG. 23A is a graph illustrating a change in luminance according to a viewing angle when the liquid crystal display is viewed in a direction parallel to the transmission axis of the polarizer, and FIG. 23B is a graph when viewed from a direction perpendicular to the transmission axis of the polarizer, and FIG. 23C. And FIG. 23D is a graph showing the case viewed from the direction forming 45 degrees or 135 degrees with the transmission axis of a polarizing plate, respectively.

24 and 25 show viewing angle characteristics when the structures according to the tenth and eleventh embodiments of the present invention are applied to a two-region VATN, respectively.

The liquid crystal display according to the exemplary embodiment of the present invention illustrated in FIGS. 5A to 14 may be applied to a multi-domain vertically aligned TN-LCD by making the buffing direction coincide with the x-axis direction of the biaxial compensation film or the a-plate compensation film. have.

In addition, the liquid crystal display device of the present invention using a compensation film includes a voltage controlled birefringence (ECB) VATN-LCD, a fringe controlled multi-domain VATN-LCD, and an in-plane switching (IPS) mode VATN-. It can also be applied to LCD.

As described above, the present invention can provide a liquid crystal display having a wide viewing angle, high contrast ratio, and good gray scale display performance by using a vertically aligned liquid crystal and a compensation film.

Claims (26)

Vertically aligned liquid crystal cell having a negative dielectric anisotropy injected therein and having a first surface and a second surface opposite the first surface, and a first a plate compensation film attached to the first surface of the liquid crystal cell. And a pair of polarizing plates attached to an outer surface of a first c plate compensation film, a second surface of the liquid crystal cell, and a compensation film attached to an outer side of the first a plate compensation film and the first c plate compensation film. And a direction having the largest refractive index in the first a plate compensating film is parallel or perpendicular to a transmission axis of an adjacent polarizing plate. The liquid crystal display of claim 1, further comprising a second c plate compensating film attached to a second surface of the liquid crystal cell. The liquid crystal display of claim 2, further comprising a second a plate compensation film attached to an outer surface or an inner surface of the second c plate compensation film. The liquid crystal display of claim 3, wherein a direction having the largest refractive index in the second a plate compensating film is parallel or perpendicular to a transmission axis of an adjacent polarizing plate. 5. The liquid crystal display of claim 1, wherein the direction perpendicular to the first surface of the liquid crystal cell is a z-axis, is in the first surface of the liquid crystal cell, and is in the first or second a plate compensating film. The direction of having the largest refractive index is the x-axis, and the refractive indices in the x-axis and z-axis directions of the first or second a-plate compensating film or the first or second c-plate compensating film are referred to as nx and nz, respectively. When the cell spacing of the liquid crystal cell is d, when only the first a plate compensation film and the first c plate compensation film are attached, the retardation value (nx-nz) * d of the first a plate compensation film and c The difference between the sum of the retardation value (nx-nz) * d of the plate compensation film and the retardation value of the polarizing plate and the retardation value due to the birefringence of the liquid crystal cell is 15% or less of the retardation value due to the birefringence of the liquid crystal cell, and the first a plate compensating film, the first c plate compensating film and the When the second c plate compensating film is attached, a retardation value (nx-nz) * d of the first a plate compensating film, a retardation value (nx-nz) * d of the first c plate compensating film, and the second c The difference between the sum of the retardation values (nx-nz) * d of the plate compensation film and the retardation value of the polarizing plate and the retardation value due to birefringence of the liquid crystal cell is 15% or less of the retardation value due to birefringence of the liquid crystal cell, and the first a When the plate compensation film, the second a plate compensation film, the first c plate compensation film and the second c plate compensation film are attached, a delay value (nx-nz) * d of the first a plate compensation film; Retardation value (nx-nz) * d of the second a plate compensating film, retardation value (nx-nz) * d of the first c plate compensating film, retardation value of the second c plate compensating film (nx-nz ) * d and the difference between the sum of the delay values of the polarizing plates and the delay values due to the birefringence of the liquid crystal cell are the delays due to the birefringence of the liquid crystal cell. Of the liquid crystal display device is not more than 15%. The liquid crystal display according to any one of claims 1 to 4, wherein the direction perpendicular to the first surface of the liquid crystal cell is a z-axis, and is in the first surface of the liquid crystal cell and is in the first or second a plate compensating film. The direction of having the largest refractive index is in the x-axis, the direction in the first surface of the liquid crystal cell and perpendicular to the x-axis is in the y-axis, and the x- and y-axis directions of the first or second a plate compensating film When the refractive indices are nx and ny, respectively, and the cell spacing of the liquid crystal cell is d, when only the first a plate compensation film is attached, the retardation value of the first a plate compensation film (nx-ny) * d is between 0 and 100 nm, and when the first a plate compensation film and the second a plate compensation film are attached, the retardation value (nx-ny) * d of the first a plate compensation film and the second a Liquid crystal display in which the sum of the retardation values (nx-ny) * d of the plate compensation film is between 0 and 100 nm Value. The liquid crystal cell of claim 1, wherein the liquid crystal cell is applied to a pair of transparent substrates facing each other, and two or more regions each having different buffing directions and coated on inner surfaces of the two transparent substrates. And a liquid crystal material having negative dielectric anisotropy injected between the vertical alignment layers. The liquid crystal cell according to claim 7, wherein a direction perpendicular to the first surface of the liquid crystal cell is defined as a z-axis, and a difference between the delay values due to the refraction in the first surface of the liquid crystal cell is 15% or less of the delay value due to the birefringence of the liquid crystal cell. And a delay value of the first a plate compensation film when the first a plate compensation film, the second a plate compensation film, the first c plate compensation film and the second c plate compensation film are attached (nx−). nz) * d, retardation value of the second a plate compensating film (nx-nz) * d, retardation value of the first c plate compensating film (nx-nz) * d, retardation of the second c plate compensating film The difference between the sum of the values (nx-nz) * d and the delay value of the polarizing plate and the delay value due to birefringence of the liquid crystal cell is 15% or less of the delay value due to birefringence of the liquid crystal cell. 8. The liquid crystal display of claim 7, wherein a direction perpendicular to the first surface of the liquid crystal cell is a z-axis, and a direction within the first surface of the liquid crystal cell and having the largest refractive index in the first or second a plate compensating film. In the axial direction, a direction in the first surface of the liquid crystal cell and perpendicular to the x axis is represented as the y axis, and the refractive indices in the x and y axis directions of the first or second a plate compensating film are nx and ny, respectively. When the cell spacing of the liquid crystal cell is d, when only the first a plate compensating film is attached, the retardation value (nx-ny) * d of the first a plate compensating film is between 0 and 100 nm. When the first a plate compensation film and the second a plate compensation film are attached, a delay value (nx-ny) * d of the first a plate compensation film and a delay value of the second a plate compensation film ( liquid crystal display wherein the sum of nx-ny) * d is between 0 and 100 nm. Vertically aligned liquid crystal cell having a negative dielectric anisotropy injected therein and having a first surface and a second surface opposite the first surface, and a first biaxial compensation film attached to the first surface of the liquid crystal cell. And a pair of polarizing plates attached to an outer surface of a first c plate compensation film, a second surface of the liquid crystal cell, and a compensation film attached to an outer side of the first biaxial compensation film and the first c plate compensation film. And a direction having the largest refractive index in the first biaxial compensation film is parallel or perpendicular to a transmission axis of an adjacent polarizing plate. The liquid crystal display of claim 10, further comprising a second c plate compensating film attached to a second surface of the liquid crystal cell. The liquid crystal display of claim 11, further comprising a second biaxial compensation film attached to an outer surface or an inner surface of the second c plate compensation film. The liquid crystal display of claim 12, wherein a direction having the largest refractive index in the second biaxial compensation film is parallel or perpendicular to a transmission axis of an adjacent polarizing plate. The liquid crystal display according to any one of claims 10 to 13, wherein the direction perpendicular to the first surface of the liquid crystal cell is a z-axis, and is in the first surface of the liquid crystal cell and in the first or second biaxial compensation film. The direction of having the largest refractive index is the x-axis, and the refractive indices of the x-axis and z-axis directions of the first c plate, the second c plate, the first biaxial or second biaxial compensation film are nx and nz, respectively. When the cell spacing of the liquid crystal cell is d, when only the first c plate compensation film and the first biaxial compensation film are attached, the retardation value of the first c plate compensation film (nx-nz) * The difference between the sum of d, the retardation value (nx-nz) * d of the first biaxial compensation film and the retardation value of the polarizing plate, and the retardation value due to birefringence of the liquid crystal cell is 15% or less of the retardation value due to birefringence of the liquid crystal cell. And the first c plate compensation film, the first biaxial compensation film, and the second c plate When a YT compensation film is attached, a delay value (nx-nz) * d of the first c plate compensation film, a delay value (nx-nz) * d of the first biaxial compensation film, and the second c plate compensation The difference between the sum of the retardation value (nx-nz) * d of the film and the retardation value of the polarizing plate and the retardation value due to the birefringence of the liquid crystal cell is 15% or less of the retardation value due to the birefringence of the liquid crystal cell, and the first c plate compensation When the film, the first biaxial compensation film, the second c plate compensation film and the second biaxial compensation film is attached, the retardation value (nx-nz) * d of the first c plate compensation film, 1 delay value (nx-nz) * d of the biaxial compensation film, delay value (nx-nz) * d of the second c plate compensation film, and delay value (nx-nz) * of the second biaxial compensation film d and the difference between the sum of the delay values of the polarizing plate and the delay value due to the birefringence of the liquid crystal cell is not more than 15% of the delay value due to the birefringence of the liquid crystal cell When devices. The liquid crystal display according to any one of claims 10 to 13, wherein the direction perpendicular to the first surface of the liquid crystal cell is a z-axis, and is in the first surface of the liquid crystal cell and in the first or second biaxial compensation film. The direction having the largest refractive index is in the x-axis, the direction in the first surface of the liquid crystal cell and perpendicular to the x-axis is in the y-axis, and the x- and y-axis directions of the first or second biaxial compensation film When the refractive index of is nx and ny, respectively, and the cell spacing of the liquid crystal cell is d, when only the first biaxial compensation film is attached, the retardation value of the first biaxial compensation film (nx-ny) * d is between 0 and 100 nm, and when the first biaxial compensation film and the second biaxial compensation film are attached, the retardation value (nx-ny) * d of the first biaxial compensation film and the second A liquid crystal display device wherein the sum of the retardation values (nx-ny) * d of the biaxial compensation film is between 0 and 100 nm. The liquid crystal cell according to any one of claims 10 to 13, wherein the liquid crystal cell is applied to a pair of opposing transparent substrates and two or more regions each having an inner surface of the two transparent substrates and having different buffing directions. And a liquid crystal material having negative dielectric anisotropy injected between the vertical alignment layers. 17. The liquid crystal display of claim 16, wherein a direction perpendicular to the first surface of the liquid crystal cell is defined as a z-axis, and a direction within the first surface of the liquid crystal cell and having the largest refractive index in the first or second biaxial compensation film. The refractive indexes in the x-axis and z-axis directions of the first c plate, the second c plate, the first biaxial or second biaxial compensation film are referred to as nx and nz, respectively, and the cell spacing of the liquid crystal cell is In the case of d, when only the first c plate compensation film and the first biaxial compensation film are attached, the retardation value (nx-nz) * d of the first c plate compensation film and the first biaxial compensation The difference between the sum of the retardation value (nx-nz) * d of the film and the retardation value of the polarizing plate and the retardation value due to the birefringence of the liquid crystal cell is 15% or less of the retardation value due to the birefringence of the liquid crystal cell, and the first c plate compensation The film, the first biaxial compensation film and the second c plate compensation film is attached The retardation value (nx-nz) * d of the first c plate compensating film, the retardation value (nx-nz) * d of the first biaxial compensation film, and the retardation value of the second c plate compensation film (nx−) nz) * d and the difference between the sum of the delay values of the polarizing plate and the delay value due to birefringence of the liquid crystal cell is 15% or less of the delay value due to the birefringence of the liquid crystal cell, and the first c plate compensation film and the first biaxial property When the compensation film, the second c plate compensation film and the second biaxial compensation film are attached, the retardation value (nx-nz) * d of the first c plate compensation film and the delay of the first biaxial compensation film Value (nx-nz) * d, retardation value (nx-nz) * d of the second c plate compensation film, retardation value (nx-nz) * d of the second biaxial compensation film, and retardation value of the polarizing plate. A liquid crystal display device wherein the difference between the sum and the delay value due to birefringence of the liquid crystal cell is 15% or less of the delay value due to birefringence of the liquid crystal cell. 17. The liquid crystal display of claim 16, wherein a direction perpendicular to the first surface of the liquid crystal cell is defined as a z-axis, and a direction within the first surface of the liquid crystal cell and having the largest refractive index in the first or second biaxial compensation film. In the axis, the direction in the first surface of the liquid crystal cell and perpendicular to the x axis is the y axis, and the refractive indices of the x and y axis directions of the first or second biaxial compensation film are nx and ny, respectively. When the cell spacing of the liquid crystal cell is d, when only the first biaxial compensation film is attached, the retardation value (nx-ny) * d of the first biaxial compensation film is between 0 and 100 nm. , When the first biaxial compensation film and the second biaxial compensation film are attached, the retardation value (nx-ny) * d of the first biaxial compensation film and the retardation value (nx) of the second biaxial compensation film liquid crystal display wherein the sum of -ny) * d is between 0 and 100 nm. Vertically aligned liquid crystal cell having a negative dielectric anisotropy injected therein and having a first surface and a second surface opposite the first surface, and a first biaxial compensation film attached to the first surface of the liquid crystal cell. And a pair of polarizers attached to a second surface of the liquid crystal cell and an outer surface of the first biaxial compensation film, wherein the direction having the largest refractive index in the first biaxial compensation film is adjacent to the polarizer. Liquid crystal display device parallel or perpendicular to the transmission axis. The liquid crystal display of claim 19, further comprising a second biaxial compensation film attached to the second surface of the liquid crystal cell. The liquid crystal display of claim 20, wherein a direction having the largest refractive index in the second biaxial compensation film is parallel or perpendicular to a transmission axis of an adjacent polarizing plate. 22. The liquid crystal display according to any one of claims 19 to 21, wherein the direction perpendicular to the first surface of the liquid crystal cell is z-axis, and is in the first surface of the liquid crystal cell and in the first or second biaxial compensation film. When the direction having the largest refractive index is the x-axis, the refractive indexes in the x-axis and z-axis directions of the first or second biaxial compensation film are nx and nz, respectively, and the cell spacing of the liquid crystal cell is d. , When only the first biaxial compensation film is attached, the difference between the sum of the delay value (nx-nz) * d of the first biaxial compensation film and the delay value of the polarizing plate and the retardation value due to birefringence of the liquid crystal cell 15% or less of the delay value due to birefringence of the liquid crystal cell, and when the first biaxial compensation film and the second c plate compensation film are attached, the retardation value of the first biaxial compensation film (nx-nz) * The sum of d and the delay value (nx-nz) * d of the second biaxial compensation film and the delay value of the polarizing plate and The liquid crystal display device whose difference of the delay value by birefringence of a liquid crystal cell is 15% or less of the delay value by birefringence of a liquid crystal cell. 22. The liquid crystal display according to any one of claims 19 to 21, wherein the direction perpendicular to the first surface of the liquid crystal cell is z-axis, and is in the first surface of the liquid crystal cell and in the first or second biaxial compensation film. The direction having the largest refractive index is in the x-axis, the direction in the first surface of the liquid crystal cell and perpendicular to the x-axis is in the y-axis, and the x- and y-axis directions of the first or second biaxial compensation film When the refractive index of is nx and ny, respectively, and the cell spacing of the liquid crystal cell is d, when only the first biaxial compensation film is attached, the retardation value of the first biaxial compensation film (nx-ny) * d is between 0 and 100 nm, and when the first biaxial compensation film and the second biaxial compensation film are attached, the retardation value (nx-ny) * d of the first biaxial compensation film and the second A liquid crystal display device wherein the sum of the retardation values (nx-ny) * d of the biaxial compensation film is between 0 and 100 nm. 22. The liquid crystal cell according to any one of claims 19 to 21, wherein the liquid crystal cell is divided into a pair of opposing transparent substrates and two or more regions each having an inner surface of the two transparent substrates and having different buffing directions. And a liquid crystal material having negative dielectric anisotropy injected between the vertical alignment layers. 25. The liquid crystal display of claim 24, wherein the direction perpendicular to the first surface of the liquid crystal cell is a z-axis, and x is a direction within the first surface of the liquid crystal cell and having the largest refractive index in the first or second biaxial compensation film. The first biaxial compensation film when the refractive indexes in the x-axis and z-axis directions of the first or second biaxial compensation film are nx and nz, respectively, and the cell spacing of the liquid crystal cell is d. In the case where only is attached, the difference between the sum of the delay value (nx-nz) * d of the first biaxial compensation film and the delay value of the polarizing plate and the retardation value due to birefringence of the liquid crystal cell is the delay value due to birefringence of the liquid crystal cell. Is less than or equal to 15%, and when the first biaxial compensation film and the second c plate compensation film are attached, the retardation value (nx-nz) * d of the first biaxial compensation film and the second biaxial compensation The sum of the retardation value (nx-nz) * d of the film and the retardation value of the polarizing plate and the birefringence of the liquid crystal cell A liquid crystal display device wherein the difference between the delay values is 15% or less of the delay value due to birefringence of the liquid crystal cell. 25. The liquid crystal display of claim 24, wherein the direction perpendicular to the first surface of the liquid crystal cell is a z-axis, and x is a direction within the first surface of the liquid crystal cell and having the largest refractive index in the first or second biaxial compensation film. In the axis, the direction in the first surface of the liquid crystal cell and perpendicular to the x axis is the y axis, and the refractive indices of the x and y axis directions of the first or second biaxial compensation film are nx and ny, respectively. When the cell spacing of the liquid crystal cell is d, when only the first biaxial compensation film is attached, the retardation value (nx-ny) * d of the first biaxial compensation film is between 0 and 100 nm. When the first biaxial compensation film and the second biaxial compensation film are attached, the retardation value (nx-ny) * d of the first biaxial compensation film and the retardation value of the second biaxial compensation film ( liquid crystal display wherein the sum of nx-ny) * d is between 0 and 100 nm.