JPH09179123A - Liquid crystal display element and production of liquid crystal display element. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody the formation of a liquid crystal display element to a large capacity while well maintaining its display grade. SOLUTION: The liquid crystal display element 8 of an OCB mode (optically compensated birefringence mode) is constituted by forming oriented films A18a of a pretilt angle 5 deg. in the central parts of pixel regions 17 and forming oriented films B18b of a pretilt angle 7 deg. in the peripheral parts of the pixel regions 17, thereby shortening the time before the entire surface of the liquid crystal display element 8 of the OCB mode attains bend arrangement. The liquid crystal display element 47 of TFT drive by a TN system is constituted by forming the oriented films E57a of the pretilt angle 5 deg. in the central parts of the pixel electrode regions 56 and forming the oriented films F57b of the pretilt angle 7 deg. in the peripheral parts of the pixel regions 56, thereby lessening the occurrence of a tilt reverse and increasing the capacity. The high-fineness display is thus obtd.

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 element, and more particularly to a liquid crystal display element and a method for manufacturing the liquid crystal display element, which can easily obtain a large capacity and high definition.

[0002]

2. Description of the Related Art In recent years, because of the great advantages of thinness, light weight and low power consumption, various devices ranging from small ones such as wristwatches and calculators to word processors and personal OA devices such as desktop personal computers. A liquid crystal display element is often used as the display element. Most of these liquid crystal display elements use nematic liquid crystal, and the display system can be roughly classified into two systems of a birefringence mode and an optical rotation mode.

As a birefringence mode liquid crystal display element using twisted nematic liquid crystal, for example, STN (Super Twisted N) having a molecular arrangement twisted by 180 ° or more.
The STN type liquid crystal display element has a steep electro-optical characteristic, so that the structure is simple and the manufacturing cost is low. This makes it possible to easily realize a large screen display.

On the other hand, the liquid crystal display element of the optical rotation mode is 90 °
TN (Twisted Nem) with twisted molecular arrangement
atic) type liquid crystal display element, and since this TN type liquid crystal display element exhibits a high contrast ratio, it is used for clocks, calculators, etc., and exhibits good gradation displayability.
Since the response speed is relatively fast (tens of milliseconds), TFT
A switching element such as a (thin film transistor) is provided for each pixel, and is applied to OA equipment and the like, which is required to have large-capacity and high-contrast display performance.

By the way, in recent years, this TN type TFT liquid crystal display element performs gradation display, but the contrast ratio and the display color change depending on the viewing angle and direction due to display inversion, black crushing, white spots and the like. There is a visual angle dependency.

Therefore, in order to improve the viewing angle dependency, as disclosed in JP-A-64-88520,
The direction in which liquid crystal molecules rise from the electrode substrate within one pixel (hereinafter abbreviated as pretilt direction) differs by 180 ° 2.
Two Domain TN (hereinafter referred to as TDTN) method for improving the viewing angle dependence by using a liquid crystal display element having two regions
Is abbreviated. ), And Y. Koike, et. al (1
992, SID, p798), a splay array is used, and two regions having different pretilt directions are provided in one pixel to obtain the same effect as TDTN.
A method of dividing one pixel into two regions having different molecular arrangements, such as ain Divided TN (hereinafter abbreviated as DDTN), has been proposed.

However, in these methods, in order to form two kinds of alignment films that change the pretilt direction in a fine region, after applying a resist on the alignment film subjected to the alignment treatment in a predetermined direction, Further, this is exposed to a mask, patterned by development, and then rubbed in the opposite direction, so that the number of steps is increased as compared with the conventional TN type liquid crystal display element, resulting in a significant cost increase, which is suitable for practical use. Had the problem of not having.

In order to solve such a problem, Y. Ymag
uchi, et. al (SID93DIGEST, p
p277-280), a voltage is applied to a nematic liquid crystal layer having a non-twisted splay alignment to generate a bend alignment, and the tilt state of liquid crystal molecules is controlled by an applied voltage value within an applied voltage range that maintains this bend alignment. However, the phase difference in the liquid crystal layer is controlled by a voltage to improve the viewing angle dependence, and the output is a birefringence effect type liquid crystal display mode.
cally Compensated Birefri
It has been proposed that the distance mode (hereinafter abbreviated as OCB mode). In addition, P. Bos, et. al
(SID83DIGEST, pp30-31) also proposes a similar liquid crystal display mode.

This OCB mode liquid crystal molecular alignment is shown in FIG.
As shown in FIG. 9, the upper half 2a and the lower half 2b of the liquid crystal layer 2 of the liquid crystal display element 1 are always symmetrical. Accordingly, the viewing angle (observation angle) is shown in the horizontal direction of FIG.
Even if the lens is tilted, the viewing angle characteristics become symmetric, and by disposing the retardation plate 3 having biaxial optical anisotropy, the refractive index ellipses of the liquid crystal layer 2 and the retardation plate 3 can be set in any voltage state. The body becomes a sphere (that is, it becomes an optical medium that does not have three-dimensional refractive index anisotropy), and from this state where the refractive index ellipsoid is a sphere, a phase difference is generated in the left and right directions, so that all viewing angles In, the voltage control in which the phase difference changes from 0 to 1/2 wavelength is possible, and the display mode has almost no viewing angle dependency.

[0010]

Conventionally, an OCB-mode liquid crystal in which a phase difference in a liquid crystal layer is controlled by a voltage is used as a liquid crystal display device which can realize a low cost because of improved viewing angle dependence and easy manufacture. Display devices have been proposed.

However, in this OCB-mode liquid crystal display element, the electro-optical characteristics are not so steep, so in a large-sized display device, driving is usually performed by active elements such as TFTs, and the electrode substrate is used. A gate line and a signal line are arranged around the upper pixel electrode. Therefore, an electric field may be generated between the pixel electrode and the wiring around the pixel electrode, and in this state, there is a problem that transfer from the spray arrangement to the bend arrangement is unlikely to occur at the peripheral edge of the pixel electrode.

Therefore, if the angle formed by the liquid crystal molecules and the electrode substrate (hereinafter abbreviated as the pretilt angle) is increased to facilitate the bend alignment, the liquid crystal molecules tend to form the twist alignment, and the stable operation is ensured. However, there is a new problem that the response speed and the viewing angle characteristics are deteriorated.

Further, not only in the OCB mode liquid crystal display element but also in the twisted nematic mode liquid crystal display element, when driving is performed by an active element such as a TFT with the increase in capacity, as shown in FIG. 4 and a gate line 5 or a signal line (not shown), a horizontal electric field 6 is generated, so that liquid crystal molecules 7 are formed in a peripheral direction of the pixel electrode 4 in a direction different from a pretilt direction such as a reverse direction or a horizontal direction. There is a problem in that a force for tilting acts and a reverse tilt domain is generated in the vicinity of the end portion of the pixel electrode 4, resulting in deterioration of display quality.

If the pretilt angle is increased in order to prevent tilt reverse or the like due to the lateral electric field, the liquid crystal molecules can easily take a twisted arrangement, stable operation cannot be obtained, and the response speed and viewing angle dependency deteriorate. Was causing a new problem.

In view of the above, the present invention eliminates the above-described problems, and in an OCB-mode liquid crystal display element that improves viewing angle dependence, the display operation is stabilized when an active element is used to realize a large-capacity display image. , The purpose is to improve the display quality. Further, also in a liquid crystal display element of a twisted nematic mode or the like, it is an object to improve the display quality by stabilizing the display operation when driven by the active element.

[0016]

As a first means for solving the above problems, the present invention provides a first electrode having a first electrode.
A liquid crystal display device comprising: an electrode substrate, a second electrode substrate having a second electrode and opposed to the first electrode substrate with a gap therebetween, and a liquid crystal composition sandwiched in the gap. An angle (pretilt angle) formed between liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate is formed by the first electrode substrate and the second electrode substrate. The peripheral portion is set to be larger than the central portion of the pixel area.

The present invention also provides a second object for solving the above problems.
As means, a first electrode substrate having a first electrode and a first alignment film is opposed to the first electrode substrate having a second electrode and a second alignment film with a gap therebetween. A liquid crystal display device comprising a second electrode substrate and a liquid crystal composition sandwiched in the gap and in which a molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film forms a bend alignment. In, the angle (pretilt angle) formed between the liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate is defined as the first electrode substrate and the second electrode substrate.
The peripheral portion is set to be larger than the central portion of the pixel region formed by the electrode substrate.

The present invention also provides a third aspect for solving the above problems.
As means, a first electrode substrate having a first electrode and a first alignment film is opposed to the first electrode substrate having a second electrode and a second alignment film with a gap therebetween. A second electrode substrate; and a liquid crystal composition sandwiched in the gap and in which the molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film forms a twisted arrangement of about 90 °. In the liquid crystal display element, the angle (pretilt angle) formed between the liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate is set to the first electrode substrate and the second electrode substrate. The peripheral portion is set to be larger than the central portion of the pixel region formed by the electrode substrate.

The present invention also provides a fourth aspect for solving the above-mentioned problems.
As the means, in any one of the first means to the third means, the peripheral portion of the pixel region is shielded by the shield means.

The present invention also provides a fifth aspect for solving the above problems.
As the means, in the second means or the third means, the first alignment film and / or the second alignment film is composed of two kinds of alignment films formed by a photolithography technique.

The present invention also provides a sixth aspect for solving the above problems.
As means, a first electrode substrate having a first electrode and a first alignment film and a second electrode substrate having a second electrode and a second alignment film are opposed to each other with a gap therebetween. A method for manufacturing a liquid crystal display device, comprising a liquid crystal composition sandwiching between a second electrode substrate a liquid crystal composition in which a molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film forms a bend alignment. At a wavelength of 400 nm or less in the first alignment film and / or the second alignment film located in the central portion or the peripheral portion of the pixel region formed by the first electrode substrate and the second electrode substrate. Comprises a step of irradiating light,
Angle formed between liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate (pretilt angle)
Is such that the peripheral portion is larger than the central portion of the pixel region.

The present invention also provides a seventh object for solving the above problems.
As means, a first electrode substrate having a first electrode and a first alignment film and a second electrode substrate having a second electrode and a second alignment film are opposed to each other with a gap therebetween. Between the second electrode substrates, the molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film is approximately 90.
In a method of manufacturing a liquid crystal display device that sandwiches a liquid crystal composition that forms a twisted array, the liquid crystal composition is located at a central portion or a peripheral portion of a pixel region formed by the first electrode substrate and the second electrode substrate. The method further comprises the step of irradiating the first alignment film and / or the second alignment film with light having a wavelength of 400 nm or less, and liquid crystal molecules in the liquid crystal composition, the first electrode substrate and / or the second alignment film. The angle formed with the electrode substrate (pretilt angle) is set such that the peripheral portion is larger than the central portion of the pixel region.

With such a structure, according to the present invention, the wiring for driving is provided around the pixel electrode in accordance with the increase in capacity, and the display image can be made finer even though the peripheral portion of the pixel region is affected by the electric field. To achieve high-quality image display.

Particularly, in the OCB mode liquid crystal display element, the transition from the splay alignment to the bend alignment of the liquid crystal molecules in the peripheral portion of the pixel region can be easily performed.
The present invention aims to increase the capacity and the definition of a liquid crystal display device that maintains good viewing angle dependence. Further, even in a twisted nematic mode liquid crystal display element, tilt reverse of liquid crystal molecules in the peripheral portion of the pixel region due to increase in capacity is prevented, and high definition display is achieved.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. Reference numeral 8 denotes a dot matrix type OCB mode liquid crystal display element, which has a thickness of 1500 angstroms on the surfaces of the first and second glass substrates 12 and 13 forming the first and second electrode substrates 10 and 11. First and second transparent electrodes 14 and 16 formed of ITO (indium-tin-oxide) and having a width of 10 mm and a pitch of 12 mm are formed in a stripe pattern, and the liquid crystal display element 8 has a 10 mm square pixel area. 17 are patterned in a matrix.

Alignment film A1 is formed on both transparent electrodes 14 and 16 of the first and second electrode substrates 10 and 11 as follows.
8a and an alignment film B18b are formed.

That is, first, an alignment film A18a made of polyimide (SE-150; manufactured by Nissan Chemical Industries, Ltd.) having a pretilt angle of 5 ° is formed on both transparent electrodes 14 and 16 by a printing method.
The film was formed to a thickness of angstrom. Furthermore, a polyimide having a pretilt angle of 7 ° (SE-72
An alignment film B18b made of 10: Nissan Chemical Co., Ltd.) was formed to a thickness of 1000 angstrom by the printing method.

As a result, the alignment film A18a having a pretilt angle of 5 ° is formed in the central portion of the pixel region 17 surrounded by the dotted line in FIG. 1, and the pretilt angle is formed in the peripheral portion of the pixel region 17. An alignment film B18b of 7 ° is formed.

Here, the alignment film A18a and the alignment film B18b
Is oriented in the direction of the arrow s in the first electrode substrate 10 and oriented in the direction of the arrow t in the second electrode substrate 11.

The first and second electrode substrates 10 and 11 thus formed each have a spacer 2 having a grain size of 7.5 μm.
And a sealing agent (not shown) made of a thermosetting resin are bonded to form a liquid crystal cell having a thickness of 7.5 μm. The liquid crystal composition (ZLI-1
132; E.I. 22 manufactured by Merck Co., Ltd. (without chiral agent) is injected.

Reference numeral 23 is a polycarbonate retardation plate which is a biaxial optical compensation film attached to a liquid crystal cell (when the in-plane component of the refractive index is ndx, ndy and the thickness component is ndz ( ndx-ndz) / (ndx-n
dy) value is 9 and retardation value is 100 nm
24a and 24b are first and second polarizing plates whose polarization axes are orthogonal to each other. This phase plate 23
The direction of the highest refractive index of the alignment films A18a and B18b
Is arranged so as to be orthogonal to the orientation direction of the polarizing plate 24a,
24b is attached to the liquid crystal cell and the retardation film 23 so that the optical axis forms an angle of 45 ° with the alignment direction.

By applying a drive voltage of 1.5 to 5 V to all the pixels of the dot matrix type OCB mode liquid crystal display element 8 thus formed, it takes time until the entire display area is changed from the splay arrangement to the bend arrangement. As a result of the measurement, the liquid crystal display element 8 was transferred at a driving voltage of 5 V for 2 seconds, which was extremely rapid.

When the liquid crystal display element 8 was driven and the viewing angle dependence of the contrast was measured, as shown in the isocontrast curve in FIG. 5, almost uniform high-quality display was obtained in all directions.

Further, the occurrence of tilt reverse was not observed and a high quality display was obtained.

The first embodiment and the second embodiment described later
Table 1 shows the driving time and the alignment state of the embodiment and Comparative Examples 1 and 2.

[0036]

[Table 1] From the above, in such a configuration, in the OCB mode liquid crystal display element 8 for improving the viewing angle dependency, the pixel region 1
Since the pretilt angle of the liquid crystal molecules in the peripheral portion of 7 is made larger than the pretilt angle of the liquid crystal molecules in the central portion, the liquid crystal molecules can be rapidly transferred from the splay alignment to the bend alignment during driving, and the good viewing angle dependence is obtained. It is possible to realize high-speed driving of the liquid crystal display device while maintaining the above, and it is possible to apply to a device having a large capacity.

[Comparative Example 1] This [Comparative Example 1] is the same as in the above-mentioned [First Embodiment] except that the polyimide having a pretilt angle of 5 ° is formed on the entire surfaces of the first and second transparent electrodes 14 and 16. SE-150; Nissan Chemical Co., Ltd.) 1000 by printing method
The film is formed to have an angstrom thickness to form an alignment film, and the rest is the same as that of the first embodiment. That is,
The pretilt angle due to the alignment film of the liquid crystal display element in [Comparative Example 1] is uniformized to 5 ° over the entire pixel region.

A driving voltage of 1.5 to 5 V was applied to all the pixels of the liquid crystal display device thus obtained, and the time taken for the entire display area to change from the splay array to the bend array was measured. It took 20 seconds at 5 V, which was extremely long, and the display quality was also deteriorated due to the occurrence of tilt reverse.

[Comparative Example 2] This [Comparative Example 2] is the same as the above-mentioned [First Embodiment] except that the polyimide having a pretilt angle of 7 ° is formed on the entire surface of the first and second transparent electrodes 14 and 16. SE-7210; Nissan Chemical Co., Ltd.) 100 by printing method
The alignment film is formed by forming a film having a thickness of 0 angstrom, and the rest is the same as that of the first embodiment. That is,
[The pretilt angle due to the alignment film of the liquid crystal display element in Comparative Example 2 is made uniform to 7 ° over the entire pixel region.

A driving voltage of 1.5 to 5 V was applied to all the pixels of the liquid crystal display device thus obtained, and the time required for the entire display area to change from the splay array to the bend array was measured. Although the transfer was extremely quick at 5 V for 1 second, the display quality was deteriorated due to the occurrence of twist reverse.

[Second Embodiment] Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 6 to 9. 27
Is a TFT-driven OCB mode liquid crystal display element,
The red (R), green (G), and blue (B) color filters 29 are formed on the first glass substrate 31 of the electrode substrate 28, and a thickness of 150 is provided between the color filters 29.
A black matrix 37, which is made of 0 angstrom chromium (Cr) and covers the peripheral portion of the pixel region 36, is provided.
A common electrode 33 made of ITO of 00 angstrom is formed.

Further, on the second glass substrate 32 of the second electrode substrate 30, it is driven by the TFT driving element 34 which is made of ITO having a thickness of 1500 angstroms and which receives a driving signal from the signal line 34a and the gate line 34b. A pixel electrode 35 having a pixel size of 110 × 330 μm is formed.

Alignment made of polyimide (SE-150; manufactured by Nissan Chemical Industries, Ltd.) having a pretilt angle of 5 ° in the central portion surrounded by the dotted line in FIG. 6 in the pixel area 36 formed by both electrodes 33, 35. A film C38c is formed to a thickness of 1000 angstroms by a printing method, and a polyimide (SE-721) having a pretilt angle of 7 ° is formed on the peripheral portion of the pixel region 36.
0; manufactured by Nissan Kagaku Co., Ltd.), an alignment film D38d having a thickness of 1000 Å is formed by a printing method.

That is, first, an alignment film C18c made of polyimide (SE-150; manufactured by Nissan Chemical Industries, Ltd.) having a pretilt angle of 5 ° was formed on both electrodes 33 and 35 by a printing method to a thickness of 1000 angstrom. Further, an alignment film D18d made of polyimide (SE-7210; manufactured by Nissan Chemical Industries, Ltd.) having a pretilt angle of 7 ° is formed on the entire surface of the alignment film C18c by a printing method.
After forming a film having a thickness of 00 angstrom, a resist coating process, an exposure process, and a development / etching process are performed to form an alignment film D3 having a pretilt angle of 7 ° only on the peripheral portion of the pixel region 36.
It is running 8d.

Further, the alignment films C38c and D38 formed on the first electrode substrate 28 and the second electrode substrate 30 are formed.
The d is oriented in the arrow u direction and the arrow v direction shown in FIG. 7, respectively.

The first and second electrode substrates 28 and 30 formed in this way are the spacers 3 having a grain size of 7.5 μm.
9 is bonded with a sealant made of thermosetting resin through 9,
A liquid crystal cell having a thickness of 7.5 μm is obtained. The liquid crystal composition (ZLI-1132; E. Merck;
(Manufactured by the company: no chiral agent) 40 is injected.

Reference numeral 41 denotes a polycarbonate retardation plate which is a biaxial optical compensation film attached to a liquid crystal cell (when the in-plane component of the refractive index is ndx, ndy and the thickness component is ndz, (ndx -Ndz) / (ndx-nd
y) has a value of 9 and a retardation value of 100 nm), and 42a and 42b are first and second polarizing plates whose polarization axes are orthogonal to each other. The direction in which the retardation plate 41 has the largest refractive index is arranged so as to be orthogonal to the alignment directions of the alignment films C38c and D38d, and the polarizing plates 42a and 42b are arranged so that the optical axis forms an angle of 45 ° with the alignment direction.
It is attached to the liquid crystal cell and the retardation plate 41.

Using the TFT-driven OCB mode liquid crystal display element 27 thus formed, a driving voltage of 2 to 6 V is applied to all pixels to measure the time until the entire display area is changed from the splay arrangement to the bend arrangement. As a result, as shown in [Table 1], when the driving voltage of the liquid crystal display element 27 was 6 V, the transition was extremely quick in 2 seconds.

When the liquid crystal display element 27 was driven and the viewing angle dependence of the contrast was measured, it was possible to obtain a high-quality display which was almost uniform in all directions, as in the first embodiment.

[Third Embodiment] Next, the third embodiment of the present invention will be described.
An embodiment will be described with reference to FIGS. 10 to 12.
Reference numeral 47 is a TN type TFT driven liquid crystal display element,
On the first and second glass substrates 51 and 52 of the first and second electrode substrates 48 and 50, a common electrode 53 made of ITO having a thickness of 1500 angstrom and a signal line 5 are formed.
4a, TFT to which a drive signal is sent by the gate line 54b
Pixel size 800 × 80 driven by the driving element 54
A pixel electrode 55 of 0 μm is formed.

Polyimide (SE having a pretilt angle of 5 ° is formed in the center of the pixel region 56 formed by both electrodes 53 and 55.
-150; manufactured by Nissan Kagaku Co., Ltd.), an alignment film E57a having a thickness of 1000 angstroms is formed by a printing method, and polyimide (SE- having a pretilt angle of 7 ° is formed around the alignment film E57a which is the peripheral portion of the pixel region 56). 7210; manufactured by Nissan Kagaku Co., Ltd.), and an alignment film F57b having a thickness of 800 Å is formed by an inkjet method.

Here, the alignment film E57a and the alignment film F5 formed on the first electrode substrate 48 and the second electrode substrate 50, respectively.
7b is oriented so that the liquid crystal molecules of the liquid crystal composition 59 held between the two electrode substrates 48 and 50 are twisted by 90 °.

The first and second electrode substrates 48 and 50 thus formed are bonded together by a sealant made of a thermosetting resin via a spacer 58 having a particle size of 5 μm, and a liquid crystal having a thickness of 5 μm. Get the cell. A liquid crystal composition (ZLI-1132; manufactured by E. Merck: no chiral agent) 59 is injected into the gap of the liquid crystal cell.

Reference numerals 61a and 61b denote first and second polarizing plates whose polarization axes are orthogonal to each other. The first and second polarizing plates 61a and 61b are attached to the liquid crystal cell so as to be orthogonal to the alignment directions of the alignment films E57a and F57b.

When the thus-formed TN-type TFT-driven liquid crystal display element 47 was driven, the edge reverse generated at the peripheral portion of the pixel region 56 was small, the contrast ratio was 120, and high-quality display was obtained. .

Table 2 shows the contrast ratios of the third embodiment, fourth and fifth embodiments described later, and Comparative Example 3.

[0057]

[Table 2] With this configuration, in the TFT-driving liquid crystal display element 47 for increasing the capacity, the pretilt angle of the liquid crystal molecules in the peripheral portion of the pixel region 56 is made larger than the pretilt angle of the liquid crystal molecules in the central portion. As compared with the prior art, the edge reverse of the peripheral portion can be reduced, and a high-quality display with good contrast can be obtained.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, a black matrix is arranged in the third embodiment described above, and the same parts as those in the third embodiment are designated by the same reference numerals and the description thereof will be omitted.

That is, the first electrode substrate 64 constituting the TN type TFT driven liquid crystal display element 63 is formed of chromium (C) having a thickness of 1500 angstroms on the first glass substrate 51.
r) and has a black matrix 66 which covers the peripheral portion of the pixel region 56, and the common electrode 53 made of ITO having a thickness of 1500 angstrom is formed on the black matrix 66.

When the liquid crystal display element 63 of the TN type TFT drive formed in this way is driven, the edge reverse occurring at the peripheral portion of the pixel region 56 is small and the peripheral portion causing the edge reverse is covered with the black matrix 66. As a result, the edge reverse did not reach the opening of the pixel region 56, the contrast ratio became 170, and high-quality display was obtained.

[Fifth Embodiment] Next, the fifth embodiment of the present invention will be described.
An embodiment will be described with reference to FIGS. 16 to 18.
Reference numeral 67 is a TN-type TFT-driven liquid crystal display element, and the first electrode substrate 68 has a thickness of 1 on the first glass substrate 70.
A black matrix 72 made of chromium (Cr) having a thickness of 500 angstroms and covering the peripheral portion of the pixel region 71.
On the black matrix 72, a common electrode 7 made of ITO having a thickness of 1500 angstrom is formed.
3 are formed.

Further, on the second glass substrate 76 of the second electrode substrate 74, it is driven by the TFT drive element 77 which is made of ITO having a thickness of 1500 angstrom and which sends a drive signal by the signal line 77a and the gate line 77b. A pixel electrode 78 having a pixel size of 110 × 330 μm is formed.

An alignment film G80 is formed on both electrodes 73, 78 of the first and second electrode substrates 68, 74 as follows.
a, an alignment film H80b is formed.

That is, first, an alignment film G80a made of polyimide (SE-7210; Nissan Chemical Co., Ltd.) having a pretilt angle of 7 ° is formed on both electrodes 73 and 78 by a printing method.
Form a film with a thickness of angstrom. Further, the periphery of the pixel region 71 is covered with a mask pattern, and the alignment film G80a at the center of the pixel region 71 is irradiated with a light beam having a wavelength of 254 nm, and the pretilt angle of the light irradiation portion is changed to 5 ° for alignment. The film H80b is formed.

As a result, an alignment film H80b having a pretilt angle of 5 ° is formed in the center of the pixel region 71,
An alignment film G80a having a pretilt angle of 7 ° is formed on the peripheral portion of the pixel region 71.

The alignment films G80a and H80b formed on the two electrode substrates 68 and 74 are the same as the two electrode substrates 6 and 6, respectively.
The liquid crystal composition 82 sandwiched between 8 and 74 has 9 liquid crystal molecules.
Orientation treatment is performed so that it is twisted by 0 °.

The first and second electrode substrates 68 and 74 thus formed are adhered to each other with a sealant made of a thermosetting resin via a spacer 83 having a particle diameter of 5 μm, and a liquid crystal having a thickness of 5 μm. A cell is formed, and a liquid crystal composition (ZLI-1132; manufactured by E. Merck: without chiral agent) 82 is injected into a gap between the liquid crystal cells.

Reference numerals 86a and 86b denote first and second polarizing plates whose polarization axes are orthogonal to each other. The first and second polarizing plates 86a and 86b are attached to the liquid crystal cell so as to be orthogonal to the light distribution directions of the alignment films G80a and H80b.

When the liquid crystal display element 67 of the TN type TFT drive formed as described above is driven, the edge reverse occurring at the peripheral portion of the pixel region 71 is small and the peripheral portion causing the edge reverse is covered with the black matrix 72. Therefore, the edge reverse does not reach the opening of the pixel region 71, the contrast ratio becomes 200, and high-quality display,
Was obtained.

[Comparative Example 3] This [Comparative Example 3] is different from the above-mentioned [Fifth Embodiment] in the manufacturing method of the alignment film G80a and the alignment film H80b, and the alignment film G and the alignment film H are different.
Are formed by a printing method, and the others are the same as those in the fifth embodiment.

However, when the liquid crystal display device thus obtained was driven, the manufacturing accuracy of the alignment film was inferior to that in the "fifth embodiment", and the pixel region and the alignment film G,
Since there is a shift in H, edge reverse is likely to occur, and the one with edge reverse on the opening is 4 / 5P.
However, the contrast ratio was as low as 80, and the display quality was impaired.

The present invention is not limited to the above-described embodiment, and changes can be made without departing from the spirit of the present invention. For example, the set angles of the pretilt angles of the central portion and the peripheral portion of the pixel region are good. The liquid crystal material may be STN type or the like, and the driving means of the liquid crystal display element may be replaced with TFT and MIM may be used.

[0073]

As described above, according to the present invention, by increasing the pretilt angle of the liquid crystal molecules in the peripheral portion of the pixel region as compared with the central portion of the pixel region, the liquid crystal generated in the peripheral portion of the pixel region during the conventional driving. It is possible to prevent tilt reversal of molecules and easily realize a large-capacity and high-definition liquid crystal display element.

[Brief description of the drawings]

FIG. 1 is a partial plan view showing an alignment film A and an alignment film B on first and second electrode substrates according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the liquid crystal display element of the first embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram showing a pretilt angle of a pixel region according to the first embodiment of the present invention.

FIG. 4 is a schematic explanatory view showing a rubbing direction according to the first embodiment of the present invention.

FIG. 5 is a graph showing isocontrast characteristics of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 6 is a partial plan view showing a first electrode substrate of a liquid crystal display element according to a second embodiment of the present invention,
(B) is a partial plan view showing the second electrode substrate.

FIG. 7 is a schematic sectional view taken along the line 6B-B ′ of the second embodiment of the present invention.

FIG. 8 is a schematic sectional view taken along the line 6C-C ′ of the second embodiment of the present invention.

FIG. 9 is a schematic explanatory diagram showing a pretilt angle of a pixel region according to the second embodiment of the present invention.

FIG. 10 shows a liquid crystal display element of a third embodiment of the present invention, (a) is a partial plan view showing the first electrode substrate thereof,
(B) is a partial plan view showing the second electrode substrate.

FIG. 11 is a view of a third embodiment of the present invention shown in FIGS. 10D-D ′.
It is a schematic sectional drawing in a line.

FIG. 12 is a schematic explanatory diagram showing a pretilt angle of a pixel region according to the third embodiment of the present invention.

FIG. 13 is a partial plan view showing a first electrode substrate of a liquid crystal display element according to a fourth embodiment of the present invention,
(B) is a partial plan view showing the second electrode substrate.

FIG. 14 is a view of FIGS. 13E-E ′ of the fourth embodiment of the present invention.
It is a schematic sectional drawing in a line.

FIG. 15 is a schematic explanatory diagram showing a pretilt angle of a pixel region according to the fourth embodiment of the present invention.

FIG. 16 is a partial plan view showing a first electrode substrate of a liquid crystal display element according to a fifth embodiment of the present invention,
(B) is a partial plan view showing the second electrode substrate.

FIG. 17 shows a fifth embodiment of the present invention, FIG. 16F-F ′.
It is a schematic sectional drawing in a line.

FIG. 18 is a schematic explanatory diagram showing a pretilt angle of a pixel region according to the fifth embodiment of the present invention.

FIG. 19 is a cell configuration diagram showing a configuration of a conventional OCB mode liquid crystal display element.

FIG. 20 is a schematic explanatory diagram showing an electric field and a molecular tilt direction of a conventional TFT liquid crystal display element.

[Explanation of symbols]

 8 ... Liquid crystal display element 10, 11 ... 1st and 2nd electrode substrate 12, 13 ... 1st and 2nd glass substrate 14, 16 ... 1st and 2nd transparent electrode 17 ... Pixel area 18a ... Alignment film A 18b ... Alignment film B 22 ... Liquid crystal composition 23 ... Retardation plate 24a, 24b ... First and second polarizing plates

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahito Ishikawa, 8th Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock company, Toshiba Yokohama Works (72) Inventor, Atsushi Manabe 8th, Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Company Toshiba Yokohama Office

Claims (7)

[Claims] 1. A first electrode substrate having a first electrode, a second electrode substrate having a second electrode and opposed to the first electrode substrate with a gap therebetween, and sandwiched in the gap. In the liquid crystal display device including the liquid crystal composition, the angle between the liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate (pretilt angle).
Is set so that the peripheral portion is larger than the central portion of the pixel region formed by the first electrode substrate and the second electrode substrate. 2. A first electrode substrate having a first electrode and a first alignment film, and a first electrode substrate having a second electrode and a second alignment film facing each other with a gap. A liquid crystal display comprising: a second electrode substrate, and a liquid crystal composition that is sandwiched in the gap and has a bend alignment in a molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film. In the element, an angle (pretilt angle) formed between liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate.
Is set so that the peripheral portion is larger than the central portion of the pixel region formed by the first electrode substrate and the second electrode substrate. 3. A first electrode substrate having a first electrode and a first alignment film, and a first electrode substrate having a second electrode and a second alignment film facing each other with a gap. A second electrode substrate, and a liquid crystal composition sandwiched in the gap and in which the molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film forms a twisted arrangement of about 90 °. In a liquid crystal display device provided, an angle (pretilt angle) formed between liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate.
Is set so that the peripheral portion is larger than the central portion of the pixel region formed by the first electrode substrate and the second electrode substrate. 4. The liquid crystal display device according to claim 1, wherein a peripheral portion of the pixel region is shielded by a shield means. 5. The method according to claim 2, wherein the first alignment film and / or the second alignment film is composed of two kinds of alignment films formed by a photolithography technique. Liquid crystal display element. 6. A first electrode substrate having a first electrode and a first alignment film, and a first electrode substrate having a second electrode and a second alignment film, which are opposed to each other with a gap therebetween. Manufacture of a liquid crystal display device in which a liquid crystal composition having a bend alignment in a molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film is sandwiched between second electrode substrates In the method, the first alignment film and / or the second alignment film located in the central portion or the peripheral portion of the pixel region formed by the first electrode substrate and the second electrode substrate is 400 nm thick.
An angle formed by the liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate (pretilt angle)
The method of manufacturing a liquid crystal display element is characterized in that the peripheral portion is larger than the central portion of the pixel region. 7. A first electrode substrate having a first electrode and a first alignment film, and a first electrode substrate having a second electrode and a second alignment film, which are opposed to each other with a gap therebetween. Between the second electrode substrates, the molecular alignment state defined by the alignment ability of the first alignment film and the second alignment film is about 90.
In a method of manufacturing a liquid crystal display device sandwiching a liquid crystal composition having a twisted arrangement, the liquid crystal composition is located at a central portion or a peripheral portion of a pixel region formed by the first electrode substrate and the second electrode substrate. 400 nm in the first alignment film and / or the second alignment film
An angle formed by the liquid crystal molecules in the liquid crystal composition and the first electrode substrate and / or the second electrode substrate (pretilt angle)
The method of manufacturing a liquid crystal display element is characterized in that the peripheral portion is larger than the central portion of the pixel region.