JPH10206834A - Liquid crystal display device and its manufacture method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a liquid crystal display device which has a wide field angle, responds fast, and prevents display defects such as sticking and a flicker. SOLUTION: This liquid crystal display device is provided with a 1st substrate 1 and a 2nd substrate 2 which have their opposite surfaces sectioned into 1st areas 18 where liquid molecules are vertically oriented and 2nd areas 19 wherein liquid crystal molecules 17 are horizontally oriented so that a 1st area 18 and a 2nd area 19 face each other and a liquid crystal layer 3 which is sandwiched between the 1st substrate 1 and 2nd substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely used as display devices for watches, calculators and the like because they can be made thinner and can be driven at a low voltage. In particular, a TN type liquid crystal display device in which an active switch element such as a TFT (thin film transistor) is incorporated in each pixel exhibits a display performance comparable to that of a CRT and is used for a display of a personal computer, a television, or the like. However, the TN type liquid crystal display device has the disadvantage that the response speed is slow and the viewing angle is narrow.

As a display method having a fast response speed, HAN is used.
(Hybrid Aligned Nematic) type liquid crystal display devices. In this method, a substrate subjected to a vertical alignment process and a substrate subjected to a horizontal alignment process are opposed to each other, and a liquid crystal between the substrates is hybrid-aligned. The HAN type has a faster response speed than the TN type, but has a strong viewing angle dependency in the rising direction of the molecule,
The viewing angle is narrower than the TN type. To solve the above problem, a D-HAN type display method has been proposed ("Kobayashi et al., Technical Report of IEICE", 199).
March 2006, P.S. 1 ").

FIG. 9 shows a D-HAN type liquid crystal display device.
FIG. 3 is a diagram schematically illustrating a configuration for pixels. Reference numeral 1 denotes a first support substrate 11, a pixel electrode 13, and an alignment film 15.
2 is a second substrate composed of a second support substrate 12, a counter electrode 14 and an alignment film 16, and 3 is a first substrate 1 and a second substrate 2.
Is a liquid crystal layer sandwiched between the substrate 2 of FIG. This DH
In the AN type liquid crystal display device, pixels on one substrate are divided into two regions, and the rotation directions of rising of the liquid crystal molecules 17 are opposite to each other. These two regions have a wide viewing angle to compensate for the viewing angle with each other.

[0005]

As a result of studying the characteristics of the D-HAN type cell manufactured by the present inventors, if the same image is displayed for several seconds to several minutes, the display shifts to the next image. "Burn-in" in which the previous image remains thin even after
It was found that the phenomenon referred to as remarkable occurred. Therefore, it has been found that when the same display is maintained for several minutes or longer, such as a personal computer monitor, the display quality is remarkably reduced, and the function as a monitor is not sufficiently performed.

[0006] When the cause was examined, it was found that the alignment films formed on the first and second substrates had different properties (polarity, hydrophilicity, surface energy, water absorption, etc.), so that seizure could occur. all right.

Hereinafter, this phenomenon will be described in the case where the potential of the counter electrode 14 of the second substrate 2 is fixed (= 0 V) and the voltage applied to the pixel electrode 13 of the first substrate 1 is inverted for each frame (frame Inversion drive) will be described in detail as an example.

When the liquid crystal display device is off, there is no potential difference between the counter electrode 14 and the pixel electrode 13, and ionic impurities contained in the liquid crystal are dispersed in the liquid crystal layer 3. When the liquid crystal display device is turned on, the ionic impurities are affected by the electric field between the counter electrode 14 and the pixel electrode 13. That is, when a positive voltage is applied to the pixel electrode 13,
Cations move toward the counter electrode 14 and anions move toward the pixel electrode 13. In the next frame, since the polarity is inverted and a negative voltage is applied to the pixel electrode 13, the anions move toward the counter electrode 14 and the cations move toward the pixel electrode 13.
Move towards. In this way, the ions repeatedly move in the opposite electrode direction every frame inversion.

However, when the properties of the alignment film 15 of the first substrate 1 and the alignment film 16 of the second substrate 2 are different, such as D-HAN, the alignment film 15 of the first substrate 1 and the second substrate In the second alignment film 16, the interaction between these alignment films and ionic impurities is different from each other. Therefore, the speed at which anions (or cations) move from the vicinity of the first substrate 1 to the vicinity of the second substrate 2 is different from the speed of movement from the vicinity of the second substrate 2 to the vicinity of the first substrate 1. As a result, while the liquid crystal display device continues to be driven, the vicinity of the first substrate 1 and the second substrate 2
In the vicinity, the bias of the charges occurs.

FIG. 10 is an explanatory diagram showing the offset of the charge. Here, as an example, a case where the first substrate is vertically aligned using a chromium carboxylate complex and the second substrate is horizontally aligned using a polyimide alignment film will be described.

When an electric field is applied between the electrodes 13 and 14,
As shown in FIGS. 10A and 10B, ionic impurities (cations 21 and anions 22) move in the direction of the electrodes of opposite polarity. Near the opposing surfaces of the first and second substrates,
These ions form an electric double layer (not shown).

The polyimide alignment film 16 for providing horizontal alignment has a property that anions are more easily adsorbed than the alignment film 15 for providing vertical alignment. Therefore, the anion is
The speed of moving from the vicinity of the substrate 2 to the vicinity of the first substrate 1 is
It is slower than the moving speed from the vicinity of the first substrate 1 to the vicinity of the second substrate 2. Therefore, when driven for several minutes, FIG.
As shown in (c) and (d), the anions are adsorbed on the alignment film 16 of the second substrate 2, causing a bias of the charges.

The following image is displayed by the liquid crystal display device. That is, as shown in FIG. 11A, after the display area A is turned off (pixel voltage = 0 V) for several minutes and the display area B is turned on (pixel voltage = ± 5 V) for several minutes,
Both display areas A and B are in a halftone state (pixel voltage = ± 3 V)
To In this case, in the display area B, the charges are biased in the ON state, and thus the effective voltage applied to the liquid crystal in the halftone state is different from that in the display area A. For example, assuming that the electric field intensity due to the bias of the electric charge is 0.5 V, the display area A
While +3 V and -3 V are applied to the liquid crystal of +, +3.5 V and -2.5 V are applied to the liquid crystal of the display area B. Therefore, as shown in FIG. 11B, the image of the display area B appears to remain thin. This is the "burn-in" phenomenon. Further, in the display region B, due to the bias of the charges,
The absolute value of the effective voltage applied to the liquid crystal differs between a positive polarity and a negative polarity. For this reason, the brightness of the display screen changes between the time of positive polarity and the time of negative polarity, and flicker occurs.

As shown in FIG. 9, in the D-HAN, one pixel is divided into two regions in which the rising directions of the liquid crystal are different from each other (region 91 on the second substrate 2).
And region 92). The angle β ′ formed by the main axis of the liquid crystal molecules in the region 91 on the second substrate 2 and the main axis of the liquid crystal molecules in the region 92 is 16
It is as large as 0 to 175 degrees. For this reason, the liquid crystal alignment becomes discontinuous at the boundary between the regions 91 and 92 at the time of applying a voltage (particularly halftone), and a disclination line occurs. The disclination line causes light leakage, and significantly lowers display quality.

The present invention has been made to solve the above problems, and has a wide viewing angle, a high-speed response, and a liquid crystal display device capable of preventing display defects such as image sticking and flicker, and manufacturing thereof. The aim is to provide a method.

[0016]

According to the liquid crystal display device of the present invention, each opposing surface is divided into a first region for giving vertical alignment to the liquid crystal molecules and a second region for giving horizontal alignment to the liquid crystal molecules. A first region and a second substrate disposed so that the first region and the second region face each other; and a liquid crystal layer sandwiched between the first and second substrates. Features.

In the liquid crystal display device, a rising direction of liquid crystal molecules of the liquid crystal layer sandwiched between a second region of the first substrate and a first region of the second substrate; Preferably, the rising directions of the liquid crystal molecules of the liquid crystal layer sandwiched between the second region of the second substrate and the first region of the first substrate are opposite to each other.

In the liquid crystal display device, the pretilt angle α01 in the first area is in a range of 60 to 90 degrees (more preferably, 75 to 90 degrees), and the pretilt angle α02 in the second area is Is 0 to 30
Degrees (more preferably 0 to 15 degrees), and the difference between the two pretilt angles α01 and α02 is preferably 60 degrees or more (more preferably 75 degrees or more).

The pretilt angle is an angle between the major axis of the liquid crystal molecules near the substrate facing surface (near the alignment film) and the substrate facing surface. In the liquid crystal display device, the first
And the second region are preferably provided with substantially equal areas in one pixel.

When manufacturing the liquid crystal display device, the first region can be vertically aligned by irradiating a charged or neutron particle bundle containing a halogen element as a constituent element.

Further, when manufacturing the liquid crystal display device,
Preferably, a direction of a rubbing alignment process for performing a horizontal alignment process on the second region is parallel to each other on the first and second substrates.

The liquid crystal display device of the present invention is a HAN type liquid crystal display device in which the first region for giving vertical alignment to the liquid crystal molecules and the second region for giving horizontal alignment to the liquid crystal molecules are opposed to each other. Is possible.

Also, the rising rotation direction of the liquid crystal molecules of the liquid crystal layer sandwiched between the second region of the first substrate and the first region of the second substrate, and the second rotation direction of the second substrate Area and the first
By mutually reversing the rotation directions of the rising of the liquid crystal molecules of the liquid crystal layer sandwiched between the first region of the substrate and the first region, the viewing angle characteristics are mutually compensated to achieve a wide viewing angle. be able to.

Further, the first and second substrates have one of the first and second substrates.
And the other second region are arranged so as to face each other. Accordingly, by setting the regions where the rotation directions of the rising of the liquid crystal molecules are opposite to each other, for example, to have substantially the same area in one pixel, it is possible to prevent display defects such as burn-in and flicker.

Further, if the first region is vertically oriented by irradiating a charged or neutron particle bundle containing a halogen element as a constituent element, the orientation film which has been horizontally oriented by rubbing can be easily partially vertically oriented. Can be done.

The pretilt angle α in the first region
01 is in the range of 60 to 90 degrees, the pretilt angle α02 in the second region is in the range of 0 to 30 degrees, and if the difference between the two pretilt angles α01 and α02 is 60 degrees or more, disclination at the boundary portion Since the line is not visible, the display quality can be further improved.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. First, a basic embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a diagram schematically showing a configuration for one pixel of the liquid crystal display device according to the present embodiment. 1 is a first substrate composed of a first support substrate 11, a pixel electrode 13 and an alignment film 15, 2 is a second substrate composed of a second support substrate 12, a counter electrode 14 and an alignment film 16, and 3 is a first substrate. Is a liquid crystal layer sandwiched between the first substrate 2 and the second substrate 2. The opposing surfaces of the first substrate 1 and the second substrate 2 are liquid crystal molecules 1
7 are divided into a first region 18 for giving vertical alignment to the liquid crystal molecules 17 and a second region 19 for giving horizontal alignment to the liquid crystal molecules 17.
The first region 18 and the second region 19 are arranged so as to face each other. Note that FIG. 1A shows a case where the liquid crystal display device is in an off state, and FIG. 1B shows a case where the liquid crystal display device is in an on state.
Is the liquid crystal molecule 1 circled in FIGS. 1 (a) and 1 (b).
Numeral 7 indicates a state that rises when transitioning from off to on.

In this example, the potential of the counter electrode 14 of the second substrate 2 is kept constant (= 0 V), and the pixel electrode 1 of the first substrate 1 is
The case where the voltage applied to 3 is inverted for each frame (frame inversion driving) will be described in detail as an example.

When the liquid crystal display device is off, there is no potential difference between the counter electrode 14 and the pixel electrode 13, and the ionic impurities contained in the liquid crystal layer 3 are dispersed in the liquid crystal layer 3. When the liquid crystal display device is turned on, the ionic impurities are affected by the electric field between the counter electrode 14 and the pixel electrode 13. That is, when a positive voltage is applied to the pixel electrode 13, positive ions move toward the counter electrode 14 and negative ions move toward the pixel electrode 13. In the next frame, since the polarity is inverted and a negative voltage is applied to the pixel electrode 13, the anions move toward the counter electrode 14 and the cations move toward the pixel electrode 13. As described above, the ions repeatedly move in the opposite electrode direction every frame inversion.

In the liquid crystal display device according to the present embodiment, the first region 18 and the second region 19 have different properties of the alignment film, so that the interaction between the alignment film and the ionic impurities is different. Therefore, anions (or cations)
Is moving from the vicinity of the first region 18 of one substrate to the vicinity of the second region 19 of the other substrate, and the speed of moving from the vicinity of the second region 19 of the one substrate to the vicinity of the first region 18 The speed of moving to is different.

As an example, in the case where the first region 18 is vertically aligned by performing a fluorine plasma treatment and the second region 19 is horizontally aligned using a polyimide alignment film.
This will be described with reference to FIG.

When an electric field is applied between the electrodes 13 and 14,
As shown in FIGS. 2A and 2B, ionic impurities (cations 21 and anions 22) move in the direction of the electrodes of opposite polarity. As a result, these ions form an electric double layer (not shown) near the opposing surfaces of the first substrate 1 and the second substrate.

As compared with the first region 18 providing the vertical alignment, the second region 19 providing the horizontal alignment has a higher polarity, so that the anion 22 is more easily adsorbed. Therefore, anion 2
The speed at which 2 moves from the vicinity of the second region 19 to the vicinity of the first region 18 is lower than the speed of moving from the vicinity of the first region 18 to the vicinity of the second region 19. Therefore, after driving for several minutes, as shown in FIGS.
The anion 22 is adsorbed on the region 19 of FIG. However, since the areas of the first region 18 and the second region 19 are substantially equal, the bias of the electric charge does not occur when viewed as one pixel as a whole.

The following image is displayed on such a liquid crystal display device. That is, as shown in FIG. 3A, after the display area A is turned off (pixel voltage = 0 V) and the display area B is turned on (pixel voltage = ± 5 V) for several minutes, both the display areas A and B are turned on. Halftone state (pixel voltage = ± 3
V). In this case, in the display region B, the effective voltage applied to the liquid crystal is different between the right half and the left half of one pixel, so that the light transmittance of these two regions is different. However, these two regions exist with approximately equal areas in one pixel. Since the resolution of the human eye is not high enough to distinguish a half area of one pixel, these two areas (the first area 18 and the second area 19 in FIG. 1).
Display colors appear mixed. In other words, there is no deviation of the charges as a whole for one pixel, and the light transmittance of the pixels in the display area B is equal to the light transmittance of the pixels in the display area A in the off state. Therefore, as shown in FIG. 3B, burn-in and flicker disappear.

Further, the D-type as shown in FIG.
In the case of the HAN type liquid crystal display device, the pixels on one substrate are divided into two regions, and the rotation directions of the rising of the liquid crystal molecules 17 are opposite to each other. In order to stably form these two regions, the pretilt angle (α0)
Must be given at least eight times. When the pretilt angle is less than 8 degrees, the alignment order of liquid crystal molecules decreases during driving,
Either of the two areas will dominate. as a result,
The viewing angle characteristics are no longer compensated, resulting in a decrease in viewing angle and poor display. It is technically difficult to stably provide a pretilt angle of 7 degrees or more with polyimide generally used as an alignment film. This is because, as the value of the pretilt angle departs from 0 degrees or 90 degrees, the free energy of the liquid crystal molecule alignment increases and becomes unstable.

On the other hand, in the liquid crystal display device of the present invention, the first and second regions are vertically and horizontally aligned, respectively, and the alignment state of the first and second regions, that is, the pretilt angle is different. It is very different. Therefore, it is possible to prevent the above-described problem from occurring.

In the liquid crystal display device of the present invention, the angle β formed by the main axis of the liquid crystal molecules in the first region and the main axis of the liquid crystal molecules in the second region is 120 degrees or less. As a result of the inventors 'earnest research, β (including β' of D-HAN shown in FIG. 9)
When 125 ° or more, disclination lines were found to occur during voltage application (particularly in halftone). That is, when β is equal to or less than 120 degrees, a liquid crystal alignment intermediate between the first region and the second region is taken at the boundary between the first region and the second region regardless of the magnitude of the applied voltage. Is energetically stable. On the other hand, β is 12
At 5 degrees or more, forming a discontinuous surface (disclination) at the boundary between the first region and the second region is more energy stable.

As described above, in the liquid crystal display device of the present invention,
Since β is 120 degrees or less, a disclination line does not occur, and a high-contrast liquid crystal display device with excellent display quality can be obtained.

The alignment films 15 and 16 of the first substrate 1 and the second substrate 2 are irradiated with a charged or neutral particle flux containing a halogen element as a constituent element, so that the alignment films 15 and 16 are irradiated.
6 is subjected to a vertical alignment process, which will be described in detail below.

The halogen element includes F, Cl, Br and the like. The charged or neutral particle flux includes an ion beam, plasma, and the like. Further, in the present application, irradiation with a charged or neutral particle flux is referred to as plasma treatment or ion beam irradiation for simplicity, but is not limited thereto. In a charged or neutral particle, when a halogen element is X, X ⁺ ion, X ⁻ ion, excited X atom, excited molecule having X as a constituent, cation having X as a constituent, and X as a constituent And the like.

Gases used for producing charged or neutral particle bundles include NF ₃ , CF ₄ , C ₃ F ₈ , XeF ₂ , N
HF ₂ , NH ₂ F, NCl ₃ , NHCl ₂ , NH ₂ C
1, CHF ₃ , CH ₂ F ₂ , CH ₃ F, CCl ₄ , CH
Cl ₃ , CH ₂ Cl ₂ , CHCl _{3 and the} like. In particular, a gas containing a molecule containing fluorine, such as NF ₃ , CF ₄ , and XeF ₂ , is preferable.

In a charged or neutral particle flux such as plasma,
Radicals such as fluorine atoms and chlorine atoms, excited atoms and ions, and the like are generated and collide with the alignment film surface.
Due to the collision, C-C and C-
Bonds such as H, C—O—C, C ＝ O, and C—N are broken;
After that, it is recombined with a fluorine atom or a chlorine atom (C-F or the like). The surface of the alignment film is made hydrophobic by the action of the fluorine atoms and chlorine molecules introduced in this manner, and vertical alignment can be given to the liquid crystal molecules.

As a plasma system, a parallel plate type, a magnetic field type, an electron cyclotron resonance type, or the like can be applied. By confining the plasma with a magnetic field, the processing time for hydrophobization can be reduced.

The pressure of the reaction gas is preferably 0.1 to 10 Torr, and the high frequency (13.56 MHz) power is 3 W to 3 Torr.
00W (particularly 10 to 100W) is preferable. As the alignment film, a transparent organic thin film such as polyimide, polyamide, BCB (benzocyclobutene polymer), or polyvinyl alcohol is preferable. In particular, a polyimide film obtained by imidizing a polyamic acid synthesized from the following diamine and acid anhydride is preferable. Examples of the acid anhydride include aliphatic and alicyclic tetracarboxylic dianhydrides such as butanetetracarboxylic dianhydride and 2,3,5-tricarboxycyclopentylacetic dianhydride, and pyromellitic dianhydride. And aromatic tetracarboxylic dianhydrides. Examples of the diamine include aliphatic or alicyclic diamines such as p-phenylenediamine and 4,4'-diaminodiphenylmethane.

Next, a more specific embodiment of the present invention will be described. First, a first specific embodiment will be described with reference to FIGS. Note that components corresponding to the components shown in FIGS. 1 and 2 are denoted by the same reference numerals as those in FIGS. 1 and 2.

FIG. 4 shows a liquid crystal display device according to this embodiment.
FIG. 5A is a diagram schematically illustrating a configuration of pixels, and FIG. 5A is a diagram schematically illustrating a configuration of a main part of a first substrate 1 on which a TFT (not shown) and the like are formed. FIG. 5B is a diagram schematically showing a configuration of a main part of the second substrate 2 on which a color filter (not shown) and the like are formed. 31 is an auxiliary capacitance line,
31a is a region of the second substrate facing the auxiliary capacitance line 31 formed on the first substrate, 32 is a signal line, and 33 is a gate line.

Hereinafter, the manufacturing process and the like will be described in detail. A gate metal made of a MoTa alloy was formed on the first support substrate 11 by using a magnetron sputtering method.
Next, a gate insulating film made of silicon oxide and silicon nitride was formed. An a-Si film and a channel protection film made of silicon nitride were formed thereon by a CVD method. Subsequently, after an island of a-Si was formed by etching, an ohmic layer was formed. Thereafter, a pixel electrode was formed, and a source / drain electrode made of Mo / Al was further formed. Thus, a TFT portion was formed. Finally, a passivation film using silicon oxide having a thickness of 2500 angstroms was formed on the TFT portion.

A solution prepared by dispersing a red pigment in a photosensitive BCB varnish was applied on the second support substrate 12, and an area where a red color filter was to be formed was exposed. Thereafter, the unexposed portions were removed using a developing solution to form a red color filter. Similarly, blue and green color filters were also formed on the second support substrate 12. A transparent electrode using indium tin oxide (ITO) was formed on the second support substrate 12 on which the color filters were formed. Color filters using photosensitive BCB are chemically resistant.
Excellent heat resistance.

The first support substrate 11 on which TFTs are formed and the second support substrate 12 on which color filters are formed,
After printing soluble polyimide (AL-3046 manufactured by Nippon Synthetic Rubber Co., Ltd.) used as the alignment films 15 and 16, it was baked at 80 ° C. for 1 minute using a hot plate, and further baked at 180 ° C. for 30 minutes in a N ₂ oven. Was volatilized. The thickness of the polyimide was 500 angstroms.

The polyimide alignment films 15 and 16 formed on the first and second support substrates 11 and 12 were rubbed. The rubbing cloth is made of rayon and the tip of the hair has a diameter of 0.1.
Those of 〜１０10 microns were used. The rubbing conditions were as follows: the number of rotations of the roller was 500 rpm, the moving speed of the substrate was 50 mm / s, the pushing amount was 0.5 mm, and the number of rubbing was one.
The substrate thus treated was washed with an aqueous solution containing a neutral surfactant as a main component to remove dirt (such as rubbing cloth hair) from the rubbing cloth.

The rubbed substrate was placed in a plasma chamber, and a stainless steel mask having the first region 18 as an opening was placed on the substrate. Then, the inside of the chamber was evacuated to generate plasma, and the first regions 18 on the surfaces of the alignment films 15 and 16 were subjected to a hydrophobic treatment. Specifically,
After the pressure in the chamber was set to 10 ^-6 Torr, NF ₃ gas was introduced into the chamber to 0.2 Torr, and 2
Minutes of plasma treatment. The area of the parallel plate electrode is 9
00 cm ² , distance between electrodes is 3.5 cm, high frequency power is 1
It was 3.56 MHz and 15 W. Note that the electrode on which the substrate having the alignment film was formed was grounded, and a high-frequency voltage was applied to the electrode facing the electrode so that the alignment film was not etched by the ions accelerated by the electric field. The substrate was baked in an N ₂ oven at 180 ° C. for 30 minutes, and further washed with an aqueous solution containing a neutral surfactant as a main component.
The NF ₃ gas physically adsorbed on the alignment film surface was removed.

Next, spacer particles having a diameter of 5 μm were scattered on the first substrate 1, and an epoxy sealing material mixed with a fiber having a diameter of 5 μm was applied to the periphery of the second substrate 2. Then, the first substrate 1 and the second substrate 2 were opposed to each other, the positions of both substrates were accurately adjusted, and both substrates were placed in an oven while being pressurized, and heat-treated at 160 ° C. for 3 hours. By this heat treatment, the sealing material was completely cured, and the first substrate 1 and the second substrate 2 were bonded to form a cell. After the nematic liquid crystal material was injected into this cell, the injection port was cured with an epoxy-based adhesive. A drive circuit was mounted thereon to produce a 9-inch diagonal liquid crystal display device.

In the liquid crystal panel manufactured in this manner, no disclination line is generated, and the contrast 15
0: 1 was obtained. In addition, since the liquid crystal of the present liquid crystal display device is hybrid-oriented, a high-speed response was achieved.
That is, the response time between two values (the time required to switch the display from white to black or from black to white) is 2 milliseconds (TN
The response time between gray scales was 4 ms (180 ms for the TN type).

Further, there are two regions in one pixel having substantially the same area, and the rotation directions of the rising of the liquid crystal molecules are opposite to each other. Therefore, the viewing angle characteristics can be widened by mutually compensating the viewing angle characteristics, and the contrast 10: 1 can be obtained.
The angle obtained above is a polar angle of 50 degrees in all directions,
No gradation inversion occurred even when viewed from the direction of the polar angle of 70 degrees. In addition, since there is no shift in electric charge in one pixel as a whole, image sticking or flicker does not occur, and good display quality can be obtained.

Since the vertical alignment of the first region is performed by plasma processing using a gas containing fluorine-containing molecules, the alignment film horizontally aligned by rubbing can be easily partially vertically aligned. Was completed.

Further, the alignment film was treated in the same manner as in this example, and the first region and the second region were opposed to each other to form an antiparallel cell, and the pretilt angle was measured by the crystal rotation method. As a result, the pretilt angle in the first area was 85 degrees, and the pretilt angle in the second area was 5 degrees.

Further, the liquid crystal display device of this example has good liquid crystal alignment, voltage holding ratio and contrast,
The display quality was good even after driving for 0 hours. Further, even when a liquid crystal material containing a relatively large amount of impurity ions having a resistivity of 10 ⁻¹² Ω · cm was used, no image sticking failure occurred.

Next, a second specific example embodiment will be described.
This will be described with reference to FIGS. 1 and 2
Components corresponding to the components shown in FIGS. 4 and 5 are denoted by the same reference numerals as those in FIGS. 1 and 2 and FIGS.

In the first specific embodiment described above,
One pixel is provided with two regions having the same area and in which the rotation directions of the rising of the liquid crystal molecules are opposite to each other. On the other hand, in the present embodiment, two regions having substantially the same area and having the rotation directions of the rising of the liquid crystal molecules opposite to each other are provided in four adjacent pixels, and these regions are arranged in a checkered pattern. .

Hereinafter, the manufacturing process and the like will be described in detail. The fabrication of the TFT and the like on the first substrate 1 and the fabrication of the color filter on the second substrate are the same as in the first specific embodiment described above. However,
In the present embodiment, a photosensitive acrylic varnish was used instead of the photosensitive BCB varnish when producing the color filter.

After printing a polyimide having a large number of fluorine atoms in a side chain as a vertical alignment film, on a first support substrate 11 on which a TFT is formed and on a second support substrate 12 on which a color filter is formed, 80 using a hot plate
° C. for 1 minute, was further imidized by baking 30 minutes at 180 ° C. in a N ₂ oven. The thickness of the polyimide was 500 angstroms.

Next, a region other than the region where the horizontal alignment treatment was performed on the first and second substrates was masked with a negative resist (OMR-83 manufactured by Tokyo Ohka) by a photolithography process, and rubbing treatment was performed. The rubbing cloth used was made of rayon and had a hair tip diameter of 0.1 to 10 microns. The rubbing conditions were as follows: the number of rotations of the roller was 500 rpm, the substrate moving speed was 20 mm / s, the pushing amount was 0.7 mm, and the number of rubbing times was one. After the rubbing, the negative resist was immersed in a stripping solution, peeled off, and washed with a rinse solution. further,
The rubbing cloth was washed with an aqueous solution containing a neutral surfactant as a main component to remove stains (such as rubbing cloth hairs) from the rubbing cloth. As described above, by selectively rubbing only the second region, only the second region provides horizontal alignment.

Next, 10 μm diameter spacer particles are sprayed on the first substrate 1, and a 10 μm diameter
m-fiber mixed epoxy-based sealing material was applied. Then, the first substrate 1 and the second substrate 2 were opposed to each other, the positions of both substrates were accurately adjusted, and both substrates were placed in an oven while being pressurized, and heat-treated at 160 ° C. for 3 hours.
By this heat treatment, the sealing material was completely cured, and the first substrate 1 and the second substrate 2 were bonded to form a cell.
After the nematic liquid crystal material was injected into this cell, the injection port was cured with an epoxy-based adhesive. A drive circuit was mounted on this to produce a 15-inch diagonal liquid crystal display device.

In the liquid crystal panel manufactured as described above, as shown in FIGS. 6 and 7, the boundary between the first region 18 and the second region 19 is located below the signal line 32 and the gate line 33. And the contrast was 150: 1.

Further, since the liquid crystal of the present liquid crystal display device is hybrid-oriented, a high-speed response was achieved. That is, the response time between the two values (the time required to switch the display from white to black or from black to white) is 2 milliseconds (30 milliseconds in the case of the TN type), and the response time between gradations is 4 ms. Milliseconds (180 milliseconds for the TN type).

Further, in four adjacent pixels, the area is almost the same,
There are two regions where the rotation directions of the rising of the liquid crystal molecules are opposite to each other. Therefore, the viewing angle characteristics can be mutually compensated and the viewing angle can be widened, and the angle at which a contrast of 10: 1 or more can be obtained is a polar angle of 50 degrees in both the upper, lower, left, and right directions. No key reversal occurred. In addition, since the electric charges do not shift in these four pixels, image sticking and flicker did not occur, and good display quality could be obtained.

Further, the alignment film was treated in the same manner as in this example, and the first region and the second region were opposed to each other to produce an antiparallel cell, and the pretilt angle was measured by the crystal rotation method. As a result, the pretilt angle in the first area was 90 degrees, and the pretilt angle in the second area was 10 degrees.

Further, the liquid crystal display device of this embodiment has good liquid crystal alignment, voltage holding ratio and contrast,
The display quality was good even after driving for 0 hours. Further, even when a liquid crystal material containing a relatively large amount of impurity ions having a resistivity of 10 ⁻¹² Ω · cm was used, no image sticking failure occurred.

Next, a third specific example embodiment will be described.
This will be described with reference to FIG. In addition, regarding the plane configuration,
Since FIG. 5 is similar to FIG. 5, reference is made to FIG. Components corresponding to those shown in FIGS. 1 and 2 and FIGS. 4 and 5 are denoted by the same reference numerals as those in FIGS. 1 and 2 and FIGS.

The first specific embodiment described above is
It differs in the method of orientation treatment and the like. Hereinafter, the manufacturing process and others will be described in detail. TFT on the first substrate 1
The production of the color filter on the second substrate and the like are the same as those of the first specific embodiment described above, and thus the description is omitted.

On the first support substrate 11 on which TFTs are formed and on the second support substrate 12 on which color filters are formed, soluble polyimide (AL-1051 manufactured by Nippon Synthetic Rubber Co., Ltd.) used as alignment films 15 and 16 Was printed, and baked at 80 ° C. for 1 minute using a hot plate and further at 180 ° C. for 30 minutes in a N ₂ oven to evaporate the solvent. The thickness of the polyimide was 500 angstroms.

The first and second substrates were placed in a plasma chamber, and a stainless steel mask having the first region 18 as an opening was placed on the substrate. At this time, the first substrate was fixed at an angle of 5 degrees and the second substrate was inclined at −5 degrees with respect to the electrode plane between the parallel plate electrodes. Then, the inside of the chamber was evacuated to generate plasma, and the first regions 18 on the surfaces of the alignment films 15 and 16 were subjected to a hydrophobic treatment. More specifically, after the pressure in the chamber was set to 10 ⁻⁶ Torr, CF ₄ gas was introduced into the chamber to 0.2 Torr, and plasma processing was performed for 2 minutes. The area of the parallel plate electrode is 90
0 cm ² , distance between electrodes is 3.5 cm, high frequency power is 1
It was 3.56 MHz and 15 W. A high-frequency voltage was applied to the electrode to which the substrate was fixed. Thereafter, the substrate was washed with an aqueous solution mainly containing a neutral surfactant. Since the substrate was tilted, the same effect as that obtained by performing the plasma treatment on the rubbed alignment film could be obtained.

Next, spacer particles of 5 μm in diameter were scattered on the first substrate 1, and an epoxy sealing material mixed with a fiber of 5 μm in diameter was applied to the periphery of the second substrate 2. Then, the first substrate 1 and the second substrate 2 were opposed to each other, the positions of both substrates were accurately adjusted, and both substrates were placed in an oven while being pressurized, and heat-treated at 160 ° C. for 3 hours. By this heat treatment, the sealing material was completely cured, and the first substrate 1 and the second substrate 2 were bonded to form a cell. After the nematic liquid crystal material was injected into this cell, the injection port was cured with an epoxy-based adhesive. A drive circuit was mounted thereon to produce a 9-inch diagonal liquid crystal display device.

In the liquid crystal panel manufactured in this manner, no disclination line is generated, and the contrast 15
0: 1 was obtained. In addition, since the liquid crystal of the present liquid crystal display device is hybrid-oriented, a high-speed response was achieved.
That is, the response time between two values (the time required to switch the display from white to black or from black to white) is 2 milliseconds (TN
The response time between gray scales was 4 ms (180 ms for the TN type).

Further, there are two regions in one pixel which have substantially the same area and in which the rising directions of the liquid crystal molecules are opposite to each other. Therefore, the viewing angle characteristics can be widened by mutually compensating the viewing angle characteristics, and the contrast 10: 1 can be obtained.
The angle obtained above is a polar angle of 50 degrees in all directions,
No gradation inversion occurred even when viewed from the direction of the polar angle of 70 degrees. In addition, since there is no shift in electric charge in one pixel as a whole, image sticking or flicker does not occur, and good display quality can be obtained.

Further, the alignment film was treated in the same manner as in this example, and the first region and the second region were opposed to each other to produce an antiparallel cell, and the pretilt angle was measured by the crystal rotation method. As a result, the pretilt angle in the first area was 85 degrees, and the pretilt angle in the second area was 0 degrees.

Further, the liquid crystal display device of this embodiment has good liquid crystal alignment, voltage holding ratio and contrast,
The display quality was good even after driving for 0 hours. Further, even when a liquid crystal material containing a relatively large amount of impurity ions having a resistivity of 10 ⁻¹² Ω · cm was used, no image sticking failure occurred. The present invention is not limited to the above embodiments, and can be implemented with various modifications without departing from the spirit thereof.

[0079]

According to the present invention, a wide viewing angle and a high-speed response of a liquid crystal display device can be achieved, and display defects such as burn-in and flicker can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross-sectional configuration of a basic embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of FIG. 1;

FIG. 3 is a diagram showing a display state obtained by the configuration of FIG. 1;

FIG. 4 is a diagram schematically showing a cross-sectional configuration of the first specific embodiment of the present invention.

FIG. 5 is a diagram schematically showing a plan configuration of first and third specific embodiments of the present invention.

FIG. 6 is a diagram schematically showing a cross-sectional configuration of a second specific embodiment of the present invention.

FIG. 7 is a diagram schematically showing a plan configuration of a second specific embodiment of the present invention.

FIG. 8 is a diagram schematically showing a cross-sectional configuration of a third specific embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional technique.

FIG. 10 is a view for explaining the operation of FIG. 9;

FIG. 11 is a diagram showing a display state obtained by the configuration of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate 2 ... 2nd board | substrate 3 ... Liquid crystal layer 18 ... 1st area 19 ... 2nd area

Claims (4)

[Claims] A first region for providing vertical alignment to the liquid crystal molecules, and a second region for providing horizontal alignment to the liquid crystal molecules.
And the first and second substrates are arranged so that the first region and the second region are opposed to each other, and are sandwiched between the first and second substrates. A liquid crystal display device comprising a liquid crystal layer. 2. The second region of the first substrate and the second region of the first substrate.
The rising direction of the liquid crystal molecules of the liquid crystal layer sandwiched between the first region of the substrate and the second region of the second substrate;
2. The liquid crystal display according to claim 1, wherein the rising directions of the liquid crystal molecules of the liquid crystal layer sandwiched between the first region and the first region of the first substrate are opposite to each other. apparatus. 3. The pretilt angle α in the first region
01 is in the range of 60 degrees to 90 degrees, the pretilt angle α02 in the second region is in the range of 0 degrees to 30 degrees, and the difference between the two pretilt angles α01 and α02 is 60 degrees or more. The liquid crystal display device according to claim 1. 4. A first region for providing vertical alignment to liquid crystal molecules and a second region for providing horizontal alignment to liquid crystal molecules.
And first and second substrates, each of which is arranged so that the first region and the second region are opposed to each other, and sandwiched between the first and second substrates. A method for manufacturing a liquid crystal display device, comprising: a liquid crystal layer; and irradiating a charged or neutron particle bundle containing a halogen element as a constituent element to vertically align the first region.