JPH05281545A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device simple in structure and easy to manufacture with a desirable visual angle characteristic. CONSTITUTION:A liquid crystal display device is provided with two bases having picture element electrodes 7 disposed opposedly so as to form plural picture elements, and a liquid crystal 21 held in a clearance between the bases. Each element of the display picture element electrode 7 has two regions 8, 9 different in the orientation azimuth of the liquid crystal in one picture element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having improved viewing angle characteristics so that a good image can be viewed from a wide angle on a screen.

[0002]

2. Description of the Related Art Liquid crystal display devices are used as OA devices such as word processors and personal computers, and image display devices such as portable televisions and information processing devices by taking advantage of their features such as thinness, light weight and low power consumption. .. Furthermore, it is attracting attention as a next-generation image display device that replaces cathode ray tubes in televisions and various information devices, and has a large number of pixels and a high definition screen to realize a high-quality image display over a larger area. Research and development on a driving method in that case are underway.

However, the liquid crystal display device has a drawback that the viewing angle characteristic is inferior to that of a CRT or the like. An active matrix type liquid crystal display device using a TFT switching device is effective as a liquid crystal display device that realizes a large number of pixels and high definition of a screen as described above, and a normal TN (twist nematic) type liquid crystal is used as the liquid crystal. Used, but this TN
Type liquid crystal has a relatively narrow viewing angle range. Therefore, the active matrix type liquid crystal display device using the NT type liquid crystal is
There was a problem that the viewing angle characteristics were inferior and it was difficult to see the image from an oblique direction. Therefore, it is particularly remarkable when the active matrix type liquid crystal display device using the NT liquid crystal is adopted in an application field such as a large wall television which is expected to realize high quality image display on a large screen. ,
It becomes a serious problem.

As a means for solving such a problem,
As disclosed in JP-A-61-67021, JP-A-61-198211, JP-A-61-245186, etc., the surface of a glass substrate or an insulating film underlayer formed on the surface of the glass substrate is provided in an amount of 1-100. The wave structure is formed on the order of μm, or the surface grain system of the insulating film underlayer is set to about 0.1 to 1 μm to form a wave structure. There is known a technique for improving the viewing angle characteristics by swinging the lens to the right.

However, it is difficult to form the insulating film underlayer on the surface of the glass substrate or the insulating film underlayer on the surface of the glass substrate in the order of 1 to 100 μm in this manner, which is difficult in the actual manufacturing process, and the transmission Since the light is scattered by the wavy structure, there is a problem that the displayed image is darkened as a whole and the display quality is deteriorated.

In addition, Kalluri R. Sarma et al., "A Wide
-Viewing-Angle 5-in.-Diagonal AMLCD Using Halftone
Grayscale ”, SID 1991 Digest, Paper No.27.7 p555 ~
557 discloses a technique in which an insulating film having an outer dimension slightly smaller than that of the pixel electrode is provided on the pixel electrode to improve the viewing angle characteristics.

FIG. 11 is a plan view of such a conventional liquid crystal display device, and FIG. 12 is a sectional view taken along line A ₁ -A ₂ .

The TFT 4 formed on the TFT substrate 401
Reference numeral 03 denotes a gate electrode 407 integrated with the scanning line 405, a drain electrode 411 integrated with the signal line 409, a display pixel electrode 4
Source electrode 415 and semiconductor layer 41 connected to
It is a general one whose main part is composed of 7. An insulating film 419, which is a feature of the liquid crystal display device according to this technique, is formed on the display pixel electrode 413. The insulating film 419 is provided as one large pattern of a substantially rectangular shape in which the display pixel electrode 413 is made one size smaller so as to cover the central portion of the display pixel electrode 413 while leaving the peripheral portion thereof. In addition, an alignment film 423 is formed on the surface which is in contact with the liquid crystal 421. On the other hand, the counter substrate 4
A common electrode 425 and an alignment film 427 are formed on 30. Then, the display pixel electrode 413 and the common electrode 425
The TFT substrate 401 and the counter substrate 430 are combined so as to face each other, and the liquid crystal 421 is sandwiched between the both substrates.

In the liquid crystal display device having such a structure, when a video signal voltage is applied to the display pixel electrode 413, a portion where the insulating film 419 is not disposed on the display pixel electrode 413, that is, the display pixel electrode 413 is formed. The liquid crystal 421 in the portion in contact with the peripheral portion is applied with the superimposed voltage of the video signal voltage and the voltage applied to the common electrode, and the insulating film is provided on the display pixel electrode 413, that is, the display pixel electrode. 413
A capacitance division voltage is applied to the liquid crystal 421 in the portion in contact with the center of the liquid crystal 421 via the capacitance in series with the capacitance of the liquid crystal 421 and the capacitance of the insulating film 419. In this way, the voltage applied to the liquid crystal 421 differs within one pixel.
As a result, two regions with different light transmittance of liquid crystal are formed within one pixel,
It is intended to improve the viewing angle characteristics by making the brightness of the screen when viewed from the front direction and that when viewed from the diagonal direction entirely uniform.

However, in the case where the insulating film 419 is provided on the display pixel electrode 413 as described above, the brightness of a bright portion having a high viewing angle characteristic of the screen is suppressed to make the entire viewing angle characteristic uniform. Therefore, there is a problem that the average screen of the entire screen looks dark. Alternatively, since there are two areas where the light transmittance of the liquid crystal changes stepwise within one pixel, the image displayed with this as one pixel may appear grainy or have periodicity. There is a problem that the display quality of the image deteriorates, such as when it looks like noise.

By the way, in the prior art, they are opposed to each other.
An alignment film that has been subjected to an alignment treatment such as rubbing is provided on each of the two substrates. For example, when TN liquid crystal is used, the angle between the alignment directions of the alignment films is 90 degrees.
The substrates are combined to orient the molecules of the TN liquid crystal on the substrates. A polarizing plate is provided outside the liquid crystal cell, and an image is displayed by changing the amount of light that can pass through the polarizing plate depending on the polarization angle of light that has passed through the liquid crystal.

However, in such a liquid crystal display device according to the prior art, there is a deviation in the viewing angle dependence that the display is bright and easy to see from one direction, and dark and hard to see from another direction. This is because the pretilt direction of the liquid crystal matches the vector direction of the rubbing, and the liquid crystal molecules rise in the pretilt direction when a voltage is applied. Therefore, when viewed from this direction, the optical rotatory property is easily eliminated. This is because the display is bright and easy to see, and when viewed from the opposite direction, the display is dark and difficult to see.
For example, in the case of the normally white mode, FIG.
T having a substrate subjected to rubbing orientation treatment as shown in FIG.
The screen of the FT active matrix type liquid crystal display device is
When viewed from the top to the bottom shown in A in FIG. 13, bright and good contrast appears, but when viewed from the bottom to the top shown in B in the same figure, it is dark and the contrast is lowered as a whole. appear.

As described above, in the liquid crystal display device according to the conventional technique, there is a problem that the display image becomes difficult to view because it has a viewing angle dependency, and it looks dark and has low contrast depending on the viewing direction.

[0014]

As described above, in the conventional liquid crystal display device, the one using the TN type liquid crystal has a problem that the viewing angle range is narrow and the screen is difficult to see. And even in the technology devised to solve this problem,
Set the surface of the glass substrate or the insulating film underlayer on it to 1 to 10
In the case of forming a wavy structure on the order of 0 μm, it is difficult to form the wavy structure in the actual manufacturing process, and transmitted light is scattered by the wavy structure, so that the displayed image is However, there is a problem that the display quality is deteriorated and the display quality is deteriorated.In the case of an insulating film provided on the display pixel electrodes, the displayed image looks rough and the periodic noise is generated. There is a problem in that the display quality of the image is deteriorated, such as when you see or the screen looks dark.

The present invention has been made to solve such a problem, and its purpose is to improve the display quality of an image such that the displayed image has a rough image quality or the screen looks dark. It is an object of the present invention to provide a liquid crystal display device in which the viewing angle characteristics are improved, the viewing angle is wide, and the quality of displayed images is good without causing deterioration and in actual manufacturing.

[0016]

In order to solve the above problems, a liquid crystal display device of the present invention includes two substrates having display pixel electrodes which are arranged to face each other and form a plurality of pixels, and In a liquid crystal display device having a liquid crystal sandwiched between the substrates, each pixel of the display pixel electrode is
It is characterized by having a plurality of regions having different orientations of liquid crystal in each pixel.

The angle formed by two different orientations of the liquid crystals in the two different regions is preferably 180 degrees in the case of the TN type liquid crystal.

In addition, the alignment of the liquid crystal is disturbed at the boundary between two regions having different alignment directions of the liquid crystal in one pixel.
Since so-called disclination may occur, such a boundary portion may be covered with a covering material made of a material having a high light-shielding property. As the covering material, for example, a black mask used together with a color filter, or a storage capacitor electrode made of a metal material such as Al or Cr in a TFT active matrix type liquid crystal display device is suitable.

The liquid crystal has a twist angle of 90.
A TN-type liquid crystal of about 1 degree is suitable, but not limited to this.

For example, STN (Super-Twisted Nemati) having a twist angle of about 180 to 270 degrees.
A c: super twisted type liquid crystal may be used. However, in this case, the angle formed by the two different orientations of the liquid crystals in the two different regions is set according to the viewing angle characteristics of the STN type liquid crystal used. Further, the angle formed by the opposing polarizing plates used at this time and the correction of the coloring state by the retardation plate or the like are set corresponding to the twist angle of the STN type liquid crystal used. When the angle formed by the two different orientations of the liquid crystal in the two different regions is set to an angle other than about 180 degrees, the angle formed by the two different regions is set respectively. The polarizing plates are individually arranged, and similarly, the retardation plates are also individually arranged with the correction of the coloring state corresponding to each of the two different regions.

[0021]

In the display pixel electrode, each pixel is composed of two regions having different liquid crystal orientations, and the orientation direction of one of these regions and the orientation direction of the other region form an angle of 180 degrees. The above two areas are set in different orientations so that, for example, one area looks bright when viewed from above and dark when viewed from below. The other area has the viewing angle characteristics, and the other area has the viewing angle characteristics such that it is dark and hard to see when viewed from above and bright and easy to see when viewed from below. Therefore, when viewed from each pixel, one area looks bright when viewed from above, and the other area looks bright when viewed from below. Even in the case of the entire screen including such pixels, the image looks bright and has high contrast in both directions such as the upper and lower directions.

Moreover, since the rubbing direction of the alignment film may be changed in the above two regions and the other configurations may be set to be the same in the two regions, the manufacturing process is not complicated as in the prior art, and Since conditions such as cell gap and light transmittance do not differ between the two areas, the image displayed on the liquid crystal display device according to the prior art appears to have a rough image quality, or the screen looks dark overall. The problem of deterioration of the display quality of the image is solved.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram schematically showing a planar structure of a pixel portion of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line A1-A2 thereof. is there.

The liquid crystal display device of the present embodiment has a TFT substrate 4
It is a TFT active matrix type liquid crystal display device having 0.

The TFT substrate 40 is arranged in the vicinity of a plurality of gate lines 2 and signal lines 3 arranged in a matrix on the glass substrate 11 and the intersections thereof, and is connected to the gate lines 2 and the signal lines 3. And a pixel electrode 7 arranged in a position surrounded by a matrix composed of the gate line 2 and the signal line 3 and connected to the TFT 4, a storage capacitor 19 connected to the pixel electrode 7, The membrane 14 and its main parts are constituted.

The counter substrate 50 is mainly composed of a common counter electrode 15 provided on the glass substrate 12, an alignment film 16, a black mask 17, and a color filter 18.

The TFT substrate 40 and the counter substrate 50 are approximately
The TN type liquid crystal 21 is sandwiched between the substrates with the cell gap of 5 .mu.m facing each other. The TN liquid crystal 21 has a twist angle of 90 degrees.

Further, the polarizing plate 19 and the polarizing plate 19, respectively, are provided on the outward sides of the TFT substrate 40 and the counter substrate 50 combined in this way.
20 is pasted. The two polarizing plates 19 and 20 are arranged so that the azimuth angles form 90 degrees.

The pixel electrode 7 and the common counter electrode 15 are I
It is composed of a transparent electrode such as TO.

The orientation films 14 and 16 have a thickness of about 100 nm.
The polyimide film is formed by subjecting this polyimide film to a rubbing alignment treatment for aligning the alignment of liquid crystal molecules.

In the TFT substrate 40, this rubbing orientation is in the region 8 of the pixel electrode 7 in the direction shown by the solid arrow C in FIG. Direction, and in the region 9 of the pixel electrode 7, in the direction indicated by the solid arrow D in FIG. 1, that is, with respect to each side of the pixel electrode 7.
They are arranged at an angle of 45 degrees to the left and downward, respectively, with the directions turned 180 degrees. On the other hand, in the counter substrate 50,
Each of the regions 8 and 9 has a direction changed by 180 degrees so as to intersect the rubbing orientation direction of the TFT substrate 40 at an angle of 90 degrees when the TFT substrate 40 is opposed. It is arranged. That is, in the region corresponding to the region 8 of the pixel electrode 7, the direction indicated by the dotted arrow E in FIG.
That is, the pixel electrode 7 is inclined obliquely downward to the right with an inclination of 45 degrees, and in the region 9 of the pixel electrode 7, in the direction shown by the dotted arrow F in FIG. 1, that is, with respect to each side of the pixel electrode 7. They are arranged at an angle of 45 degrees to the upper left and 180 degrees, respectively.

As described above, when the orientation direction is set in the portion of the pixel electrode 7 and the common counter electrode 15 corresponding to each pixel of the pixel electrode 7, each pixel is divided into two regions 8 and 9 having different liquid crystal orientations. In other words, one region 8 has a viewing angle characteristic that makes it easy to see brightly when viewed from above in FIG. 1 and becomes dark and difficult to see when viewed from below,
In addition, the other region 9 has a viewing angle characteristic that makes it dark and hard to see when viewed from above, and bright and easy to see when viewed from below. Therefore, when viewed from each pixel, one area looks bright when viewed from above, and the other area looks bright when viewed from below. Similarly, as a whole, when viewed from both directions such as the top and bottom, the image looks bright and has high contrast.

Moreover, the above two regions 8 and 9 are the alignment film 1
Since the rubbing directions of 4 and 16 can be changed, and the other configurations can be set the same in the two areas, the manufacturing process is not as complicated as the conventional technique, and the two areas 8 and
Since the conditions such as the cell gap and the light transmittance do not differ in 9, the displayed image looks like a rough image quality like the liquid crystal display device according to the related art, or the screen looks dark as a whole. It is possible to solve the problem of deterioration of display quality.

In addition, the two regions 8 and 9 are the alignment film 1
Since the rubbing directions of Nos. 4 and 16 are changed by 180 degrees, the two polarizing plates arranged in such a way that the azimuth angles form 90 degrees used in the conventional technique can be used as they are.

The metal electrode 1 of the storage capacitor 19 is arranged so as to cover the boundary between the two regions 8 and 9 and prevent light from passing therethrough. The metal electrode 1, the insulating layer 13, and the pixel electrode 7 sandwiching the metal electrode 1 and the insulating layer 13 sandwiches the storage capacitor 1
9 are configured.

The method of forming the alignment film of the liquid crystal display device according to the present invention will be described by focusing on the rubbing process.

First, as shown in FIG. 3, a polyimide film before the alignment treatment, which is to be the alignment film 14, is formed on the TFT substrate 40 by printing or spin coating. And area 9
Is masked with a resist 22 in advance and rubbed by a rubbing machine 60 to perform an alignment treatment of the region 8 to give the alignment film 14 the alignment direction C as shown in FIG. Then, the resist 22 is peeled off. Next, the region 8 is masked in advance with the resist 23 and rubbed by a rubbing machine 60 to perform the alignment treatment of the region 9 as shown in FIG. 1, and the alignment direction D as shown in FIG. give. Then, the resist 23 is peeled off.

Similarly, in the counter substrate 50, as shown in FIG.
As shown in FIG. 1, first, the portion corresponding to the region 9 is masked in advance with a resist and rubbed by a rubbing machine 60 to perform the alignment treatment of the region 8 to give the alignment film 16 the alignment direction E as shown in FIG. And resist 2
4 is peeled off. Next, the portion corresponding to the region 8 is masked in advance with the resist 25 and rubbed by the rubbing machine 60 to perform the alignment treatment of the region 9 as shown in FIG. 1, and the alignment direction F as shown in FIG. Alignment film 16
Give to. Then, the resist 25 is peeled off.

The orientation process is performed in this manner. In addition,
As the resists 22 to 25, general photoresists are used in this embodiment, but other than this, for example, Mo is used.
You may use such a metal thin film. In this case, since the resist has a film thickness smaller than that of the photoresist described above, it is possible to avoid the occurrence of rubbing defects near the boundary of masking by the resist.

A test pattern was displayed on such a liquid crystal display device of the present invention, and the viewing angle characteristics and the quality of the displayed image were verified. The display system was a raster system, and the signal voltage waveform of the image was a square wave.

FIG. 5 is a diagram showing the viewing angle characteristics of the liquid crystal display device of the present invention. In the figure, the horizontal axis represents the vertical angle with respect to the cell, and the vertical axis represents the screen brightness when viewed from that direction. The parameter of each curve is the signal voltage, and since the liquid crystal display device of the present embodiment adopts the normally white mode, the brightness is high when the signal voltage is 0 [V], and the brightness when it is 5 [V]. Is low.

In the figure, dashed curves 511, 51
Reference numerals 2 and 513 show the viewing angle characteristics of the liquid crystal display device according to the related art in which a single orientation is provided over the entire screen, and solid curves 501, 502, and 503 show the viewing angle characteristics of the liquid crystal display device according to the present invention. ..

As is clear from FIG. 5, the viewing angle characteristics are
When the signal voltage was 0 [V] and when the signal voltage was 5 [V], the liquid crystal display device according to the related art and the liquid crystal display device according to the present invention were almost the same. However, signal voltage 5
In the black display of [V], in the liquid crystal display device of the present embodiment, the variation in luminance in the positive direction is larger than that of the liquid crystal display device according to the related art, but it is acceptable and there is no problem. ..

On the other hand, in the halftone display of the signal voltage of 2.8 [V], the viewing angle characteristics of the liquid crystal display device according to the prior art have a great variation as shown in FIG. 5, but in the liquid crystal display device according to the present invention. The curve showing the viewing angle characteristics is almost flat, and the screen brightness seen from any angle is within 40% with little variation. From this, it was confirmed that the viewing angle characteristics of the liquid crystal display device according to the present invention are dramatically improved as compared with the liquid crystal display device according to the related art.

The curved line shown by the alternate long and short dash line in FIG. 5 is obtained by moving the metal electrode 1 of the storage capacitor 19 of the liquid crystal display device of this embodiment to a position other than the position covering the boundary between two regions having different alignment directions. 9 is a curve showing a viewing angle characteristic in the case where a display is executed by providing the transmitted light on the screen without blocking the vicinity of the boundary. As is clear from the figure, when the signal voltage is 0 [V], there is almost no difference, but when the signal voltage is 2.8 [V] and the signal voltage is 5 [V], the brightness is generally high, but It has been found that the brightness in black display at a voltage of 5 [V] does not drop to about several percent or less, and the deterioration of the contrast ratio thereby significantly impairs the display quality of the screen. In addition, when the transmitted light of this boundary portion was made visible on the screen and the display quality of the screen was examined in detail by changing the signal voltage and the setting of the liquid crystal display device in detail, the deterioration of the contrast ratio as described above was observed. In addition, it was found that display irregularities occurred, and display defects frequently occurred in this portion.

It is considered that this is because alignment disorder occurs due to disclination, misalignment between the two substrates, and the like at the boundary between the two regions having different alignment directions.

Therefore, it was confirmed that a member having a high light blocking property, such as a metal, should be provided so as to cover up such a display defect at the boundary portion as in the present embodiment. In particular,
In this embodiment, the storage capacitor 1 is used as such a member.
Since it also serves as the metal electrode 9 of 9, the aperture ratio of the pixel electrode 7 is higher than that in the case where a black mask is provided separately from the metal electrode 1, and it also has the effect of increasing the screen brightness. ing.

Further, in the present embodiment, the boundary portion between the two regions having different orientation directions is located on the metal electrode 1 of the storage capacitor 19, and the thickness of the metal electrode 1 causes the orientation film 14 in that portion. Is high. Therefore, it was confirmed that the rubbing strength at the boundary portion was increased and the alignment was made stronger, and thus the above-mentioned disorder of the alignment was suppressed. Further, since the width of the region where the contrast ratio is reduced becomes small, the area covering that portion can also be made small. This can prevent the aperture ratio of the pixel electrode 7 from decreasing, and as a result, the brightness of the screen can be increased. In this embodiment, the width of the metal electrode 1 is set to a minimum of 10 μm, taking into consideration the electrostatic capacitance of the storage capacitor 19. In this embodiment, there are two regions having different liquid crystal orientations, but the present invention is not limited to this. It may be a larger number.

(Embodiment 2) FIG. 6 is a diagram schematically showing a planar structure of a pixel portion of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 7 is a sectional view taken along line A1-A2 thereof. .. For simplification of description, the same parts are denoted by the same reference numerals as in the first embodiment.

In the liquid crystal display device of the second embodiment, the pixel electrode 7 corresponding to one pixel is divided into two with a gap provided at the boundary between the regions 8 and 9. It is different from the example. The other structure is almost the same as that of the first embodiment.

This gap is provided to prevent a display defect due to disclination which occurs at the boundary between the regions 8 and 9. That is, due to this gap, lines of electric force are emitted from the metal electrode 1 of the storage capacitor 19 and the liquid crystal 2
It will spread within 1. Then, if the alignment direction of the liquid crystal in the regions 8 and 9 is set so as to lie to the left and right around this gap, the liquid crystal tilts along the line of electric force,
Disturbance in the alignment of the liquid crystal such as disclination at the boundary is less likely to occur, and display defects at the boundary can be suppressed.

(Embodiment 3) FIG. 8 is a diagram schematically showing a two-dimensional configuration of an alignment direction of pixel portions and an arrangement of color filters 18 in a liquid crystal display device according to a third embodiment of the present invention. For simplification of description, the same parts are denoted by the same reference numerals as in the first embodiment.

The liquid crystal display device of the third embodiment is different from that of the first embodiment in that the TFT substrate 40 is characterized.
A pretilt angle is provided on the side alignment film 14 and the counter substrate 50
This is that the alignment treatment is performed so that the pretilt angle is not provided on the side alignment film 16 (the pretilt angle becomes almost 0).

In the present embodiment, a linear pattern is formed on the alignment film 16 by photolithography to perform the alignment treatment. Since such a grating does not have a pretilt angle, the directionality of the alignment is a linear pattern. It is established in both the longitudinal and longitudinal directions. That is, the alignment film 16
Even if a pretilt angle is not provided in the alignment film 14, a pretilt angle is provided in the alignment film 14 on the TFT substrate 40 side and a chiral agent or the like is added, and the pretilt angle of this alignment film 14 determines the alignment direction of the liquid crystal in that part. This is because that.

The advantage of this case is that when the TFT substrate 40 and the counter substrate 50 are combined, it is not necessary to perform highly accurate alignment between the alignment film 14 and the alignment film 16 as in the first embodiment. It is possible to avoid the disorder of the alignment caused by the misalignment. Further, since the width of the electrode 1 and the black mask 17 for covering the portion where the orientation is disturbed can be reduced, it is possible to prevent the aperture ratio from decreasing.

As a method of eliminating the pretilt angle of the alignment film 16, in addition to the above, rubbing may be performed twice so as to reciprocate.

(Embodiment 4) FIG. 9 is a diagram schematically showing a planar structure of a pixel portion of a liquid crystal display device according to a fourth embodiment of the present invention. For simplification of description, the same parts are denoted by the same reference numerals as in the first embodiment.

The liquid crystal display device of the fourth embodiment is different from that of the first embodiment in that a covering member 47 made of the same material as the signal line 2 is arranged at the boundary between the regions 8 and 9. Is. The covering member 47 may be formed by patterning when forming the signal line 2. The other structure is almost the same as that of the first embodiment.

In this case, the storage capacitor 19 is arranged so as to overlap a part of the lower portion of the pixel electrode 7 as shown in FIG. By doing so, the width of the metal electrode 1 of the storage capacitor 19 can be freely set in accordance with the required capacitance, regardless of the width of the portion where the display defect of the boundary between the regions 8 and 9 occurs. can do. It should be noted that, as an example thereof is shown in FIG. 10, a black mask 17 is used instead of the covering member 47.
The boundary between the areas 8 and 9 may be covered with.

In the first to fourth embodiments described above,
Although the case of the TFT active matrix type liquid crystal display device has been described, the present invention is not limited to this. Other XY
The present invention can be applied to a simple matrix type liquid crystal display device.

Further, as described above, the liquid crystal used is not limited to the TN type liquid crystal. STN type liquid crystal or the like may be used.

Further, the form of the division of the regions 8 and 9 is as follows.
It is not necessarily limited to the form of being divided vertically. In addition to this, for example, it may be divided into left and right to improve the viewing angle characteristics in the left and right directions. Alternatively, it can be divided into a central portion and a peripheral portion.

The areas of the regions 8 and 9 do not necessarily have to be the same. For example, as shown in FIG. 9 above,
The area 8 may have a larger area than the area 9. The area ratio of the region 8 and the region 9 may be appropriately changed according to the setting of the viewing angle characteristics and the contrast ratio of each liquid crystal display device.

Further, the pixels may be grouped and the orientation direction may be changed for each group. For example, as shown in FIG. 10 described above, three pixels in the horizontal direction may be set as one set, and the orientation direction may be changed by 180 degrees for each set. in this case,
Pixels that appear bright when viewed from an oblique direction are not visible in a line as in the first embodiment and are appropriately divided, so that uneven brightness when viewed from an oblique direction of the screen is not noticeable. Can be

Further, the orientation direction is not limited to the direction of 45 degrees with respect to the peripheral side of the pixel electrode 7 as in the above embodiment. For example, it may be parallel to the pixel electrode 7.

The alignment film can also be formed by an oblique evaporation method using SiO or the like.

It is also possible to partially provide an insulating film in the pixel portion.

[0069]

As described above in detail, according to the present invention, the display quality of a displayed image looks rough, or the screen looks dark, thereby deteriorating the display quality of the image. It is possible to provide a liquid crystal display device which has improved viewing angle characteristics, a wide viewing angle, and good image quality to be displayed without causing difficulty in actual manufacturing.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a planar configuration of a pixel portion of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is an A1-A2 cross-sectional view of a pixel portion of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an alignment treatment of a region 8 of the TFT substrate 40 according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an alignment treatment of a region 9 of the TFT substrate 40 according to the first embodiment of the present invention.

FIG. 5 is a diagram showing viewing angle characteristics of the liquid crystal display device of the present invention.

FIG. 6 is a diagram schematically showing a planar configuration of a pixel portion of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 7 is an A1-A2 cross-sectional view of a pixel portion of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 8 is a diagram schematically showing a planar configuration of an alignment direction of pixel portions and an array of color filters of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 9 is a diagram schematically showing a planar configuration of a pixel portion of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 10 is a view showing a black mask 17 arranged so as to cover a boundary portion between regions 8 and 9.

FIG. 11 is a plan view of a liquid crystal display device according to a conventional technique.

FIG. 12 is an A ₁ -A ₂ cross-sectional view of a liquid crystal display device according to a conventional technique.

FIG. 13 is a plan view showing an alignment direction of a liquid crystal display device according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal electrode 2 ... Gate line 3 ... Signal line 4 ... TFT 7 ... Pixel electrode 8, 9 ... Pixel electrode region 11 ... TFT substrate side glass substrate 12 ... Opposing substrate side glass substrate 14 ... TFT substrate side alignment Film 15 ... Common counter electrode 16 ... Alignment film on counter substrate 17 ... Black mask 18 ... Color filter 19 ... Polarizing plate on TFT substrate 20 ... Polarizing plate on opposing substrate 21 ... Liquid crystal 22, 23 ... Resist

Claims (1)

[Claims] 1. A liquid crystal display device, comprising: two substrates having display pixel electrodes arranged opposite to each other to form a plurality of pixels; and a liquid crystal sandwiched in a gap between the substrates. A liquid crystal display device in which each pixel has a plurality of regions having different liquid crystal orientations.