JPH043110A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To allow displaying with high quality for a wide range of visual angles by specifying the value of the product of the difference between the max. main refractive index and min. main refractive index of a visual angle compensating means and the optical path length of the visual angle compensating means. CONSTITUTION:A liquid crystal display element and a pair of polarizing members are provided in order to make liquid crystal displaying. The visual angle compensating means optically having double refractiveness is inserted between the liquid crystal display element and the polarizing member on at least one side in the lamination direction thereof. The direction of the max. main refractive index of this visual angle compensating means is so set as to be nearly paralleled with substantially the normal direction of the liquid crystal display element. The value of the product of the difference between the max. main refractive index and the min. main refractive index and the optical path length of the visual angle compensating means is set in a range from 200nm to 900nm. The display grade is greatly improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to improving viewing angle characteristics in a liquid crystal display.

Conventional technology Liquid crystal display devices have traditionally been used as numeric segment display devices for watches, calculators, etc., taking advantage of their characteristics of being thin, lightweight, and low power consumption! has been widely used. In recent years, matrix display systems have been adopted to display even more information. Matrix type liquid crystal display devices can be used in personal computers, text processing machines (word processors), etc. by selectively driving multiple display pixels.
Office automation such as , copiers, etc.
It is used as a display terminal for e＾automation) equipment.

Furthermore, in response to the increasing density, larger area, and diversification of display information, many technological developments have been made in connection with color display systems, such as color liquid crystal display devices that add color information. For example, (1) a guest-host effect liquid crystal in which a dye is mixed into the liquid crystal whose transmitted color varies depending on the direction of the dye molecule, and the alignment of the dye molecules follows the change in the alignment direction of the liquid crystal molecules to display two colors; (2) A method that displays color by combining a twisted nematic (abbreviated as TN) liquid crystal cell and a color polarizing plate; (3) A method that uses the change in birefringence of liquid crystal according to an applied electric field. Electric field-controlled birefringence interference (Electrieil
ly Controlled Birefringen
(4) red, green,
In a liquid crystal cell provided with a color filter layer for blue or the like, the liquid crystal layer is used as a light shutter to perform color display.

In particular, the method (4) above has the feature of being able to perform high-contrast matrix-type full-color display.
This is the display method that is currently receiving the most attention. In this method, an active element such as a thin film transistor is formed as a switching means for selecting display pixels in a liquid crystal display device, and an active drive type TN liquid crystal display method in which nematic liquid crystal molecules are twisted and oriented by 90 degrees, and a twist angle of the liquid crystal molecules are used. A multiplex drive type sub-twisted nematic ink (abbreviated as 5TN) liquid crystal display system is common, which takes advantage of the sharpness of the transmittance-applied voltage characteristic by setting the angle to 90 degrees or more.

Furthermore, active drive type TN liquid crystal display systems can be roughly divided into two types depending on how a pair of polarizing plates are arranged. In other words, there is a normally black method in which the polarization directions of a pair of polarizing plates are arranged parallel to each other and black is displayed when no voltage is applied to the liquid crystal layer (off state), and a method in which the polarization directions are arranged orthogonal to each other. The normally white method is advantageous from the viewpoint of display characteristics such as 0 display contrast, color reproducibility, and viewing angle dependence of display.

In addition, in the multiplex drive type STN liquid crystal display system, a system with an optical compensator that has a light shutter effect (black and white display) with little wavelength dependence is promising; Two-layer type <D S T N using a liquid crystal cell twisted and oriented at a twist angle
, Double SuperTwistedNes+
1tie) A liquid crystal display system and a film-added liquid crystal display system using a film having optical anisotropy. Among these, film-added liquid crystal display systems are considered promising from the viewpoint of low cost and light weight.

Problems to be Solved by the Invention FIG. 8 is an exploded sectional view of a liquid crystal display cell 33 in a conventional super twisted nematic type liquid crystal display device that performs black and white display using a retardation compensator. Here, the same reference numerals are used for members corresponding to the embodiments described later. The liquid crystal display cell 33 includes a pair of glass substrates 3.
Transparent electrodes 5 and 6 made of ITo are patterned on each opposing surface of 4, and the surfaces are coated with alignment films 7a and 8a. These glass substrates 3.4 are bonded together via a sealing resin (not shown), and a liquid crystal layer 34 is encapsulated to form a liquid crystal display cell 33.

The surfaces of the orientations M7a and M8a are subjected to a rubbing treatment in advance, whereby the encapsulated nematic liquid crystal 34 is attached to the glass substrates 3 and 4 as schematically shown in FIG.
In between, a twisted orientation of 180 degrees to 260 degrees, that is, a super twist orientation is achieved.

Normally, supertwisted nematic liquid crystal display devices exhibit remarkable birefringence due to the supertwisted orientation of the liquid crystal.
It is colored yellow green (so-called yellow green mode) or blue (so-called blue mode).

In order to prevent this coloration and improve visibility, a black and white super twisted nematic liquid crystal display device equipped with an optical retardation compensator has been developed. FIG. 8 shows a super twisted nematic type liquid crystal display device in which -axis-stretched polymer films are provided as optical retardation compensators 28, 29, 30. By using 29°30, a super twisted nematic liquid crystal display device that performs black and white display is capable of high time division driving, has a large display capacity, has a high contrast ratio in black and white display, and can provide clear display. . Furthermore, since color display is possible by providing a color filter layer, it is used as a display device for personal computers, word processors, etc.6 However, on the other hand, the viewing angle is highly dependent on the elevation angle from which the liquid crystal display panel is viewed. To,
It has the disadvantage of poor viewing angle characteristics.

An object of the present invention is to solve the above-mentioned technical problems and provide a liquid crystal display device capable of displaying high quality over a wide range of viewing angles.

Means for Solving the Problems The present invention provides a liquid crystal display element configured by interposing a liquid crystal layer between a pair of light-transmitting substrates, and an optical display element disposed on at least one side in the stacking direction of the liquid crystal display element. The direction of the maximum principal refractive index of the viewing angle compensation means is substantially In the liquid crystal display device, the maximum principal refractive index nb and the minimum principal refractive index n of the viewing angle compensation means are substantially parallel to the normal direction of the liquid crystal display element.
The product of the difference in a and the optical path length d of the viewing angle compensation means (nb-na
)-d is in the range of 200 nm to 900 nm.

The present invention also provides a liquid crystal display element configured by interposing a liquid crystal layer between a pair of transparent substrates, and an optically biaxial viewing angle disposed on at least one side in the stacking direction of the liquid crystal display element. and a pair of polarizing members arranged on opposite sides of the liquid crystal display element and the viewing angle compensating means, the direction of the maximum principal refractive index of the viewing angle compensating means being substantially in the direction of the maximum principal refractive index of the liquid crystal display element. In a liquid crystal layer display device that is substantially parallel to the normal direction, the difference between the next largest principal refractive index nc and the smallest principal refractive index na after the largest principal refractive index nb of the viewing angle compensation means, and the optical path length d of the viewing angle compensation means When the value of nc-na>・d is 20 nm to 1
This is a liquid crystal display device characterized in that it is in the range of 100n.

Function: In the liquid crystal display device of the present invention, a liquid crystal display element and a pair of polarizing members are provided to perform liquid crystal display. A viewing angle compensation means having optical birefringence is inserted between the liquid crystal display element and the polarizing member on at least one side in the stacking direction. The direction of the maximum principal refractive index of this viewing angle compensation means is set to be substantially parallel to the normal direction of the liquid crystal display element. Here, the direction of the maximum principal refractive index is the direction in which the optical means having optical birefringence has the maximum refractive index value.

More preferably, in the light transmittance-applied voltage characteristics exhibited by the liquid crystal display element and the pair of polarizing members, the sum of the thickness of the liquid crystal display element and the thickness of the viewing angle compensation means in all viewing angle directions. Set so that they are equal. Here, retardation refers to 2Ii, which includes normal light and extraordinary light propagating through an optically anisotropic medium.
This is the phase difference that occurs between different types of light.

The light that passes through the polarizing member is linear light, and when this light passes through the liquid crystal layer, normal light and extraordinary light are generated due to the birefringence of the liquid crystal, and elliptically polarized light and elliptically polarized light corresponding to the phase difference between them are generated. It may happen. Therefore, by eliminating this phase difference using the viewing angle compensating means, the light that has passed through the viewing angle compensating means becomes direct 11 (li) light. In other words, in general, the retardation value of the light that has passed through the liquid crystal display element is determined by the viewing angle. Therefore, by superimposing a viewing angle compensation means on the liquid crystal display element, which has a characteristic that the retardation value increases as the viewing angle increases, the retardation in transmitted light is canceled out and the phase difference is eliminated. do.

As a result, in the liquid crystal display device of the present invention, good display characteristics can be obtained over a wide range of viewing angles. Therefore, according to the present invention, the display quality of the liquid crystal display device is improved.

In particular, according to the present invention, the viewing angle compensating means is disposed on at least one side in the stacking direction of the liquid crystal display element and has optical biaxiality. The refractive index nb, nc, n in each of the three axial directions in the coordinate system
represents that a are different from each other, where nb>nc
>na and the optical path length approximately equal to the thickness of the viewing angle compensation means is d, then 200 nm≦(nb-na)-d≦900 nm.

Here, the rubbing directions of the alignment films formed on the pair of substrates of the liquid crystal display element intersect in a plane parallel to the substrates, and the smaller angle formed by these two rubbing directions is bisected. The line is called the 3 o'clock and 9 o'clock direction, and a first plane that includes this 3 o'clock-9 o'clock direction and the normal to the substrate is defined, and the 2nd plane of the larger angle of the two rubbing directions is defined.
The equal dividing line will be referred to as the 6 o'clock-12 o'clock direction of the clock, and a second plane including the 6 o'clock-12 o'clock direction and the normal to the substrate will be defined. The contrast ratio is set to 20 or more, which is a value that does not cause any practical problems in the applications of the liquid crystal display element, such as electronic devices such as desk-top electronic calculators that perform multiplex drive, and watches. In order to make the range of the visual angle formed by the person's line of sight and the normal line as large as possible within the first and second planes, first, it is set to a range that satisfies the above equation. In this formula,
Below 200 nm, within the first plane, i.e. 3 o'clock -
The viewing angle range cannot be increased within the plane that includes the 9 o'clock direction, and when it exceeds 900 nm, the viewing angle range cannot be increased within the second plane, that is, the plane that includes the 6 o'clock = 12 o'clock direction.

Furthermore, according to the present invention, the following equation is determined to hold.

20nm≦(nc-na)d≦100n When it is less than 100n and exceeds 1100n, it is impossible to make the contrast ratio 20 or more and to enlarge the viewing angle range in the first plane and the second plane.

Embodiment FIG. 1 is an exploded sectional view of a liquid crystal display device according to an embodiment of the present invention. In the liquid crystal display cell 36, the display liquid crystal cell 37 has transparent electrodes 5 made of ITO (indium fI5B compound) on each opposing surface of a pair of glass substrates 3.4.
．． 6 is patterned, and its surface is coated with alignment films 7a and 8a made of polyimide polymer. Each surface of orientation gi7a and gi8a is formed when a liquid crystal layer 34 is formed by sealing a liquid crystal material to be described later between the glass substrates 3 and 4.
The surface is subjected to a rubbing treatment in advance so that the liquid crystal molecules are oriented in a 240 degree supertwisted manner. These glass substrates 3.4 are bonded together via a sealing resin (not shown), and a liquid crystal layer 34 is encapsulated to form a liquid crystal display cell 36. As the liquid crystal material of the liquid crystal layer 34, for example, S-811 (manufactured by Merck & Co., Ltd.) is used as a chiral dopant to regulate the twist direction in phenylcyclohexane (PCH)-based and pyrimidine-based nematic liquid crystals having positive dielectric constant anisotropy. A mixed solution containing 0.76 wt% of is used. The refractive index anisotropy Δn of the liquid crystal layer 34 was 0.123, and the layer thickness d of the liquid crystal layer 34 was set to 7.5 μm.

On mutually opposite sides of the glass substrates 3 and 4 in the liquid crystal cell 37, a phase difference compensation plate 29 and a laminated phase difference compensation plate 2 are disposed.
8a is placed. The laminated phase difference compensating plate 28a consists of phase difference compensating plates 39 and 40. Further, on the mutually opposite N side of the phase difference compensating plates 28a and 29, there is a pair of polarizing plates 15.
16 are placed. Furthermore, a phase difference compensating plate 29 and a polarizing plate 1
6, a viewing angle compensation plate 38 according to the present invention is inserted.

Retardation compensation plate 39.40; 29 is a uniaxially stretched film made of polycarbonate;
．． 40; The retardation values for light propagating in the normal direction of 29 are 200 nm and 200 nm, respectively.
, 400 nm.

Further, the viewing angle compensation plate 38 is made of Boristine, and the second
As shown in the figure, the retardation values for light propagating in the normal direction, that is, the two principal refractive indices in the direction along the plane of the viewing angle compensation plate 38 are nc and na (nc>
na>, and the thickness (optical path length) of the viewing angle compensator 38 is d (
The value of nc-na)·d is 60 nm. Viewing angle compensation plate 3
8, the retardation value for the light propagating in the plane direction, that is, the principal refractive index along the normal direction of the viewing angle compensator 38 is Nb (nb>nc>na>(nb
The value of -na)·d is 450 nm.

FIG. 3 is a perspective view of the liquid crystal display cell 36.

The substrates 3, 4 of this liquid crystal display cell 36 are parallel to each other, a plane parallel to these substrates 3, 4 is designated by reference numeral 51, and a normal direction perpendicular to this plane 51 is designated by reference numeral 50.

FIG. 4 shows the orientation angle of liquid crystal molecules in the liquid crystal display cell 36 within the plane 51 and the phase difference compensation plate 39.40.2]
, the viewing angle compensation plate 38, and the polarizing plate 15.16. In the liquid crystal layer 34, the long axis direction of the liquid crystal molecules at the interface on the glass substrate 4 side is an arrow of 60 degrees from the 6 o'clock direction to the 9 o'clock direction. Therefore, the long axis direction of the liquid crystal molecules at the interface on the glass substrate 3 side is in the direction of arrow a3, which is twisted 240 degrees counterclockwise from the a4 direction. That is, the rubbing direction of the orientation film 8a of the glass substrate 4 is arrow a4, and the rubbing direction of the orientation W7a of the glass substrate 3 is arrow a.
It is 3.

This rubbing direction a3. The bisector of the smaller angle γ1 in the plane 51 of a4 is called the 3 o'clock-9 o'clock direction of the clock, and the larger angle γ of the rubbing direction a3a4
The bisector of 2 is called the 6 o'clock-12 o'clock direction, and the 1,000th plane 52 including the 3 o'clock-5 o'clock direction and the normal direction 50 is 6
It is orthogonal to a second plane 53 that includes the o'clock-12 o'clock direction and the normal direction 50.

In the 1,000th plane 52, the angle formed by the normal direction 50 and the line of sight 5455 is set to +θ on the 3 o'clock side or 10 on the 9 o'clock side, and this value ±θ is called a viewing angle. Also, in the second plane 53, the angle formed by the line of sight with the normal direction 50 within the 2,000th plane 53 is +θ or 1 in the 6 o'clock direction.
The 2 o'clock direction is assumed to be 1 θ and will be referred to as the viewing angle.

The maximum refractive index direction (optical axis direction) of the phase difference compensating plate 39 is 6
It is in the direction of arrow A39, which is 55 degrees from the o'clock direction to the 9 o'clock direction,
The maximum refractive index direction of the phase difference compensating plate 40 is the arrow a40 direction, which is 25 degrees from the 6 o'clock direction to the 9 o'clock direction. Therefore, the phase difference compensating plates 39 and 40 each have a maximum refractive index compensation of 3
Forms an angle of 0 degrees.

Further, the maximum refractive index direction of the phase difference compensating plate 29 is in the direction of arrow a29, which is 25 degrees from the 6 o'clock direction to the 3 o'clock direction.

Furthermore, the polarization direction a15 of the polarizing plate 15 changes from the 6 o'clock direction to the 9 o'clock direction.
It has an angle of 40 degrees toward the hour direction, and the polarization direction a of the polarizing plate 16 is
16 has an angle of 75 degrees from the 6 o'clock direction to the 3 o'clock direction.

Arrow a38 giving the principal refractive index nc of the viewing angle compensator 38
The direction is parallel to the polarization direction a16 of the polarizing plate [6].

FIG. 5 shows a duty ratio of 1/1 in the liquid crystal display cell 36.
3 is a graph showing the viewing angle dependence of contrast ratio when multiplex driving of 240 pixels is performed. Here, the viewing angle θ
As described above, is the angle from the normal direction of the substrate of the liquid crystal display cell 36. FIG. 5(1) shows the second direction including the 6 o'clock-12 o'clock direction perpendicular to the substrate surface of the liquid crystal display cell 36.
Contrast ratio when viewed from a thousand planes 53 - viewing angle characteristics p1
9 and the same characteristics p18 of the conventional liquid crystal display cell 33 are shown. It can be seen from FIG. 5(1) that the viewing angle characteristic in the second plane 53 including the 6 o'clock-12 o'clock direction is 28 degrees wider at a contrast ratio of 20 than in the conventional case shown in FIG. FIG. 5(2) shows the contrast ratio-viewing angle characteristic 121 when viewed from the 1,000th plane 52 including the 3 o'clock-9 o'clock direction perpendicular to the substrate surface of the liquid crystal display cell 36, and the conventional technique shown in FIG. The same characteristics in the liquid crystal display cell 33! 20 is shown.

In the present invention, the viewing angle at a contrast ratio of 20 is 10 degrees wider in the 1,000th plane 52 including the 3 o'clock to 9 o'clock direction than in the conventional case. By adding the viewing angle compensation plate 38 in this way, the contrast ratio can be increased and clear black and white display can be achieved.

In addition, as can be seen from the (nb-na)·d dependence of the viewing angle range in which the contrast ratio is 20 or more shown in FIG.
3.52 In order to obtain wider viewing angle characteristics than in the case of the conventional liquid crystal cell 33, (nb-na)・
The value of d needs to be set in the range of 200 nm to 900 nm. To explain this in more detail, the lines 122 and 123 in FIG. 6(1) indicate the viewing angle range (boundary) in which the contrast ratio is 20 or more in the 6 o'clock direction, and the line 1221.1' 231 indicates the range in which the contrast ratio is 20 or more in the 6 o'clock direction. Also, line l 24 in FIG. 6(2) shows the case of
．． 125 is a visual angle node I with a contrast ratio of 20 or more in the 3 o'clock direction! ! (boundary), line e 241.
1251 indicates the case in the 9 o'clock direction, that is, line l
22.123 indicates the range of the visual angle formed from the normal direction 50 to the 6 o'clock direction within the second plane 53, and the line 1221. l 2
31 is a broken line 122 indicating the viewing angle range on the 12 o'clock direction side formed with the normal direction 50 within this 2,000th plane 53.
, N221 show the characteristics of the prior art shown in FIG.

It can be seen from lines 122 and 123 that when (nb-na)-d exceeds 900, the visual angle range in the 6 o'clock direction in the second plane 53 decreases.

Also, the line l24 in FIG. 6(2) mentioned above. l 25
indicates the viewing angle range on the 3 o'clock direction side with respect to the normal direction 50 within the 1,000th plane 52, and the line r241.125
1 indicates the viewing angle in the 9 o'clock direction with respect to the normal direction 50 within this 1,000th plane 52. (nb-na)・d is 200 nm without groove, line l 24. l 25 +p
241. It can be seen from l 251 that the viewing angle range becomes smaller. Line p24°1241 shows the characteristic of the prior art of FIG.

From this, 200nm≦(nb-na)-d≦900nm =
It can be seen that by setting il), the viewing angle range can be widened.

Furthermore, with reference to FIG. 7(1), the viewing angle range (nc-na) where the contrast ratio of the liquid crystal display cell 36 is 20 or more is
)・d As can be seen from the dependence of d, FIG.
Figure 7 (1) showing the characteristics of the 1,000th plane 52 including the 9 o'clock direction
In either case, it is necessary to set (nc-na)-d in the range of 20 nm to 1100 nm in order to obtain wider viewing angle characteristics than the prior art shown in FIG.

In other words, the 70th (1) lines 132 and 133 are
The line 13211331 indicates the visual angle range in the 6 o'clock direction with respect to the normal direction 50 in the plane 53, and the line 13211331 indicates the visual angle range in the 12 o'clock direction with respect to the normal direction 50 in the second plane 53. .1321 is the 8th
Figure 1 shows the characteristics of the prior art. Lines 134 and 135 shown in FIG. 7(2) indicate the viewing angle range in the 3 o'clock direction with respect to the normal direction 50 within the 1,000th plane 52, and lines 1341. & 351 is a line l indicating the viewing angle range in the 9 o'clock direction with respect to the normal direction 50 on the first plane 52.
34.1341 shows the viewing angle characteristics of FIG.

Lines 132 and 133 in Figure 7 (1) above:
1321. I 331 and line Z in Figure 7, 2)
34. j'35;i! 341. f 351 empty, (
It can be seen that when d is less than 20 nm, the viewing angle range becomes smaller.

Also, lines 132 and 133 in FIG. 7(1) and line 134 in FIG. 7(2). l'3'5:1341.13
51, it can be seen that the viewing angle range becomes smaller when (nc-nal d exceeds 1100n. Therefore, 20 nm≦(nc-na> ・d≦1100ri
By setting (2), a wide viewing angle range can be obtained.

As explained above, the viewing angle compensating means, which has optical birefringence and whose maximum principal refractive index direction is substantially normal to the substrate surface of the display liquid crystal cell, is made of polymeric material. This can be achieved by using a film-like material formed from a liquid crystal material or an ionic crystal material, or a polymeric material in which the distribution density of electrons is uneven in the thickness direction, such as a film-like material made of polystyrene.

In such viewing angle compensating means, generally, the turbidity value of light propagating in the direction perpendicular to the liquid crystal cell substrate or in the thickness direction of the film-like material increases as the viewing angle increases. Preferably, the sum of the radiance value of the display liquid crystal cell and the radiance value of the viewing angle compensation means is set so as not to change depending on the viewing angle. By using such viewing angle compensating means in combination with a display liquid crystal cell, it is possible to eliminate the phase difference that occurs in the transmitted light of the display liquid crystal cell, realize a liquid crystal display with wide viewing angle characteristics, and improve display quality. be able to.

Further, the present invention can be applied to thin film transistors, MIM (Met
Of course, the present invention can also be suitably applied to an active drive type liquid crystal display device that performs display drive using active elements such as Al In5ulator Metal elements, diodes, and the like.

Effects of the Invention According to the present invention, since a liquid crystal display device is constructed by laminating a viewing angle compensating means on a liquid crystal display element, viewing angle dependence of display in a liquid crystal display is improved. Therefore, the display quality of the liquid crystal display device is significantly improved.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing the structure of a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 shows the refractive index na of the viewing angle compensation plate 38.
, nb, and nc; FIG. 3 is a perspective view for explaining the 3 o'clock-9 o'clock direction and the 6 o'clock-12 o'clock direction;
FIG. 4 is a diagram showing the mutual relationship between the arrangement angles of the liquid crystal display cell 36, FIG. 5 is a graph showing the viewing angle dependence of the contrast ratio in the liquid crystal display cell 36, and FIG. 6 is a graph showing the viewing angle compensation plate 38 in the viewing angle range. FIG. 7 is a graph showing the retardation (nc-na) and d dependence of the viewing angle compensation plate 38 in the viewing angle range. FIG. FIG. 3 is an exploded cross-sectional view showing the configuration of a liquid crystal display cell 33 in FIG. 3.4...Glass substrate, 5,6...Transparent electrode, 7a8
a. Alignment film 534...Liquid crystal layer, 15.16...Polarizing plate, 33.36...Liquid crystal display cell, 29.39.40.
・・Phase difference compensation plate, 38... Viewing angle compensation plate agent Patent attorney Keiichi Nishiki 1st figure nb 2nd figure Question 3 Direction diagram (nb-na>・d (40Lm) /33 i Diagram

Claims (2)

[Claims] (1) A liquid crystal display element configured by interposing a liquid crystal layer between a pair of transparent substrates, and an optically biaxial viewing angle compensation means disposed on at least one side in the stacking direction of the liquid crystal display element. and a pair of polarizing members disposed on mutually opposite sides of a liquid crystal display element and a viewing angle compensating means, the direction of the maximum principal refractive index of the viewing angle compensating means being substantially normal to the liquid crystal display element. In a liquid crystal display device that is substantially parallel to the direction, the maximum principal refractive index nb and the minimum principal refractive index na of the viewing angle compensation means
and the optical path length d of the viewing angle compensation means (nb-na)
- A liquid crystal display device characterized in that the value of d is in the range of 200 nm to 900 nm. (2) A liquid crystal display element configured with a liquid crystal layer interposed between a pair of transparent substrates, and an optically biaxial viewing angle compensation means disposed on at least one side in the stacking direction of the liquid crystal display element. and a pair of polarizing members disposed on mutually opposite sides of a liquid crystal display element and a viewing angle compensating means, the direction of the maximum principal refractive index of the viewing angle compensating means being substantially normal to the liquid crystal display element. In a liquid crystal layer display device that is almost parallel to the direction,
The value of the product (nc-na)·d of the difference between the next largest principal refractive index nc and the smallest principal refractive index na after the largest principal refractive index nb of the viewing angle compensation means and the optical path length d of the viewing angle compensation means is 20 nm. from 1
A liquid crystal display device characterized in that the wavelength is in the range of 00 nm.