JPH07248500A - Liquid crystal display panel and its production - Google Patents

Abstract

PURPOSE:To realize improved visual field characteristics by consisting oriented films formed on the inside walls of substrates of a specific polyimide film material. CONSTITUTION:The division of the orientation regions by irradiation with light or heat energy is made possible by using the polyimide having a specific functional group within the molecule as an oriented film material. This liquid crystal display panel is composed of the substrate 18 having the oriented film 26, the substrate 16 having the oriented film 22 and liquid crystals 20. At least the oriented film 22 consists of the single oriented film having microregions A, B adjacent to each other. The single oriented film is continuously rubbed in one direction along the microregions A, B and is subjected to another treatment separate from the rubbing in such a manner that the pretilt angle Y of the liquid crystals in contact with the oriented films varies from each other.

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 panel and a manufacturing method thereof, and more particularly to an alignment division type liquid crystal display panel having different alignment regions formed in pixels and a manufacturing method thereof. Here, the "alignment division type" is configured so that the alignment film applied to the inner wall of the substrate in order to obtain high viewing angle characteristics is divided into minute regions so that the alignment state of the liquid crystal is different for each minute region. Pointing to something.

[0002]

2. Description of the Related Art In recent years, the demand for active matrix type color liquid crystal display panels has been increasing. Further, with the increase of such demand, the demand for the liquid crystal display panel itself tends to be diversified, and among these, the improvement of the viewing angle characteristics is strongly demanded. That is, in such a liquid crystal panel, the contrast of the lightness and darkness of the image changes depending on the direction in which the viewer looks at the screen, so it is desirable to improve this (this is generally considered as the viewing angle characteristic of the liquid crystal panel. Recognized). For example, when viewing a liquid crystal panel that has undergone a certain orientation treatment from diagonally above, the transmissivity decreases significantly by applying a slight voltage, and the transmissivity increases again with increasing voltage. On the other hand, when the liquid crystal panel is viewed obliquely from below, the transmittance does not decrease easily even if the voltage is increased, and even if an attempt is made to obtain a black display, the display becomes relatively bright.

At present, a technique attracting attention for obtaining a high viewing angle characteristic is an alignment division technique for dividing a pixel to form different alignment regions. For example, JP-A-63-106
Japanese Patent Laid-Open No. 624 discloses that, by forming two regions having different alignment directions of liquid crystal molecules in one pixel and mixing the viewing angle characteristics in an obliquely upward direction and the viewing angle characteristics in an obliquely downward direction, We propose to improve.

FIG. 1 is a schematic view showing an alignment state of such a conventional liquid crystal display panel. This figure shows the area of one pixel for easy understanding.
A pixel is divided into two regions A and B having different alignment states of liquid crystal molecules. Light enters one of the substrates (here, the substrate on the light incident side is referred to as the lower substrate), passes through the liquid crystal sandwiched between the substrates, and exits from the other substrate (upper substrate). When the liquid crystal panel is viewed from above the upper substrate, the rubbing direction of the alignment film of the lower substrate is indicated by an arrow R _L , and the rubbing direction of the alignment film of the upper substrate is indicated by an arrow R _U.

In the region A of FIG. 1, the rubbing direction R _L of the alignment film on the lower substrate is 45 ° to the left and the rubbing direction R _U of the alignment film on the upper substrate is 45 ° to the left. The viewing angle characteristic in the case of such an alignment treatment is equivalent to that when the liquid crystal panel is viewed obliquely from above, and when a slight voltage is applied, the transmittance is significantly reduced, and the transmittance is increased again as the voltage is increased. Like This viewing angle characteristic is indicated by a double arrow in the figure. On the other hand, in the region B, the rubbing direction R _L of the alignment film on the lower substrate is 45 ° to the right and the rubbing direction R _U of the alignment film on the upper substrate is 45 ° to the right. The viewing angle characteristics in the case of such an alignment treatment are upside down from those in the above-mentioned area A.

[0006] Such a minute region A with different orientation treatment
And the minute area B are arranged side by side, the viewing angle characteristic with high transmittance and the viewing angle characteristic with low transmittance are added, and the viewing angle characteristic is as if divided by 2. The viewing angle characteristics are approached, and the viewing angle characteristics as a whole are improved. FIG. 2 is a cross-sectional view of the liquid crystal panel 1 having the minute area A and the minute area B of FIG. The liquid crystal panel 1 is, as shown in the figure, a TFT substrate 1 as a lower substrate.
6 and a CF substrate 18 as an upper substrate, and a liquid crystal 20 sandwiched between these substrates. The lower substrate 16 is provided with a transparent pixel electrode 5 and an alignment film 6, and the upper substrate 18 is provided with a transparent common electrode 7 and an alignment film 8. In Figure 1,
It is shown that the liquid crystal molecules in the minute area A rise with an upward slope to the left, and the liquid crystal molecules in the minute area B rise with an upward slope to the right. The viewing angle characteristics as described above are generated based on the tilt direction of the liquid crystal molecules.

In FIG. 2, the alignment films 6 and 8 are the alignment material layers 9 and 4 on the lower layer side and the alignment material layer 2 on the upper layer side, respectively.
It has a two-layer structure consisting of three. The alignment material layers 2 and 3 on the upper layer side are patterned by a lithographic technique so as to be minute portions corresponding to the minute areas A and B described above, and are formed on the lower layer side from the opening portion adjacent to each minute portion. The orientation material layers 9 and 4 are exposed. The orientation material layers 2 and 3 on the upper layer side, which are minute portions, are on the upper substrate 18 side and the lower substrate 1.
It is provided alternately on the 6 side. That is, in the minute area A, the alignment material layer 2 on the upper layer side of the lower substrate 16 is the upper substrate 1
8 facing the lower orientation material layer 4 side, and in the minute region B, the upper substrate 18 side orientation material layer 3 faces the lower substrate 16 side lower orientation material layer 9. It is supposed to do. Here, a minute area A in which the alignment state of the liquid crystal is different
In order to obtain the liquid crystal panel 1 having B and B, it is necessary to divide the alignment films 6 and 8 of the respective substrates into fine regions A and B and perform rubbing. When rubbing, use a mask etc. to do it selectively,
In the minute area A, the upper alignment material layer 2 on the lower substrate 16 side is rubbed in the direction indicated by the arrow _RL in the area A of FIG. 1 to form the lower alignment material layer 4 on the upper substrate 18 side. Rubbing is performed in the direction indicated by the arrow R _U in the area A of FIG. The same applies to the minute region B.

The manufacturing of the liquid crystal display panel 1 will be as shown in the flow sheet of FIG.
After the substrate is charged, the lower layer-side alignment material and the upper layer-side alignment material are sequentially applied to the inner wall of the substrate to form the alignment film. Then, a suitable resist material is applied to pattern the upper alignment layer. After forming the resist film, a series of steps of selective exposure, development / etching, and resist stripping are performed. After obtaining an alignment film patterned in a desired shape, the alignment film is rubbed, a spacer is applied, liquid crystals are injected, and a polarizing plate is attached to complete a panel.

[0009]

The structure and behavior of the conventional active matrix type color liquid crystal display panel can be easily understood from the above description with reference to FIGS. 1 and 2. Further, in the case of active matrix driving, the gate bus line C and the drain bus line (not shown) are provided on the lower substrate 16 having the pixel electrode 5. At the boundary between the minute regions A and B having different alignment states, the liquid crystal molecules tilting in the opposite directions come into contact with each other, so that the alignment of the liquid crystal is distorted and disclination occurs, and light easily leaks along the boundary line. Therefore, the gate bus line C is designed so as to come to the position of the boundary between the minute regions A and B, and the gate bus line C blocks light leaking due to disclination so that a good display can be obtained. There is.

However, as shown in FIG. 2, in the conventional structure in which the gate bus line C is designed to be located at the boundary between the minute regions A and B, the alignment material layer on the upper layer side on the lower substrate 16 side. The end portion 2a of No. 2 and the end portion 3a of the alignment material layer 3 on the upper side of the upper substrate 18 were formed at positions overlapping the gate bus line C. For this reason, the liquid crystal 20 is subject to electrolysis, ions are generated, and the liquid crystal 20 is easily deteriorated, and the performance of the liquid crystal panel 1 may be deteriorated.

One of the reasons why the liquid crystal 20 is electrolyzed
One is that the liquid crystal 20 is in contact with the upper layer side alignment material layer 2 and the lower layer side alignment material layer 4 which are made of different materials. That is, the electrolysis action is due to the same reason that two electrode pieces of different materials are inserted into the solution. Another one
One reason is that the liquid crystal 20 receives a direct current when it is driven. The number of gate bus lines C is, for example, 4
There are 00 lines, which are sequentially scanned. Each gate line C is
Only 1/400 has a positive value, and 399/400 has a constant negative value. Therefore, it can be said that the liquid crystal 20 constantly receives the DC voltage between the gate bus line C and the common electrode 7. In FIG. 2, a potential difference v ₁ is generated between the upper-layer-side alignment material layer 3 and the lower-layer-side alignment material layer 2 that face each other on the gate bus line C, and the lower substrate 16 side and the upper-layer-side alignment material layer It is shown that a potential difference v ₂ is generated between the third alignment layer 3 and the lower alignment layer 2. In particular, if the gate insulating film has a leak defect, the DC voltage applied to the liquid crystal layer and the alignment film becomes large. When the two gate bus lines C are formed side by side, the gap between the two gate bus lines C also has the same potential as the gate bus line C.

Therefore, a first object of the present invention is to provide a liquid crystal having a simple structure which can realize an improved viewing angle characteristic and can prevent the deterioration of the liquid crystal due to the generation of ions as described above. To provide a display panel. The conventional active matrix type color liquid crystal display panel is manufactured through a series of photolithography processes as described with reference to FIG. In order to form the alignment film, after the first layer (lower layer side) of the alignment material layer is applied, the second layer (upper layer side) of the alignment material layer is applied and patterned by photolithography. However, in this method, it takes a long time to divide the alignment region, and the cost is very high in terms of members and equipment. Further, since the photo process involves a wet process, there is a risk that the alignment film is damaged by the developing solution or the resist stripping solution. Damage to the alignment film causes a decrease in the pretilt angle and also causes alignment failure.

In addition, the rubbing process also has a problem. In a liquid crystal display panel with divided pixels, rubbing in opposite directions must be performed for every two minute regions. As described above, such a rubbing process requires the following two rubbing processes by photolithography. That is, in the first rubbing treatment, an alignment film is applied to the inner surface of the substrate, a resist is applied to the alignment film, an opening corresponding to one minute region is provided in the resist, and rubbing is performed in a certain direction there. , And removing the resist. Then, in the second rubbing treatment, a resist is applied to the alignment film subjected to the first rubbing, and the resist is provided with an opening corresponding to a region opposite to the one region, and rubbing in the opposite direction there. , And removing the resist.

Such a rubbing process requires two photolithography processes and two rubbing processes for the alignment film on each substrate. Therefore, it was necessary to perform the photolithography process and the rubbing process four times in total on both substrates.
However, since the photolithography process and the rubbing process are performed many times in this way, the manufacturing cost increases, and
There is a problem that the surface of the alignment film is rough and the alignment of the liquid crystal is not stable.

A second object of the present invention is, therefore, to provide an improved method for producing the improved liquid crystal display panel as described above by a simple and short-time dry process.

[0016]

The first object mentioned above is
According to the present invention, in a liquid crystal display panel in which a liquid crystal substance is sandwiched between opposing substrates, each of the substrates has an alignment film applied to its inner wall, and at least one alignment film is Polyimide film material selected from the group of: 1. Peroxide, which does not contain ether bond in the molecule,
Containing at least one moiety selected from the group consisting of ketones, esters, amines, amides and derivatives thereof, and under the action of light or heat energy, for example the reaction of said moieties with water, oxygen and / or hydrogen. As a result of, a polyimide capable of inducing a change in surface energy; 2. Containing a carbon-carbon double bond or a carbon-carbon triple bond in the molecule, and receiving the action of light or heat energy, for example, in the molecule Or a polyimide capable of causing a change in surface energy by reacting between molecules; 3. Containing a carbon-carbon double bond or a carbon-carbon triple bond in the molecule and receiving the action of light or heat energy A polyimide capable of causing a change in surface energy as a result of, for example, the reaction of said bond with water or hydrogen in air; and 4. carbon in the molecule It contains an elementary double bond or a carbon-carbon triple bond and is subjected to the action of light or thermal energy in the presence of a halogen to cause a change in surface energy, for example as a result of the reaction of said bond with a halogen. It is composed of a layer of possible polyimide;
The alignment film is composed of an aggregate of two adjacent minute regions, is continuously rubbed in one direction along the minute regions, and has different pretilt angles (liquid crystal from the substrate surface) in the minute regions. It can be achieved by a liquid crystal display panel characterized by having a rising angle of molecules.

A second object of the present invention is to apply a film material for forming the single alignment film onto a substrate in the method for manufacturing a liquid crystal display panel as described above, and then apply the film to the formed film. This can be achieved by a method for manufacturing a liquid crystal display panel, which is characterized in that light or heat energy is applied corresponding to the distribution pattern of the aggregate of the minute regions, and then rubbing treatment is performed.

The polyimide-based film material used as the alignment film material in the liquid crystal display panel of the present invention is polyimides 1 to 4 capable of inducing a change in surface energy under the action of light or heat energy. The light or heat energy applicable here can be generated from various light sources or heat sources, depending on the nature of the polyimide used, such as the particular functional groups contained in the polyimide molecule. For example, examples of light energy may include ultraviolet rays from a high-pressure or low-pressure mercury lamp, and examples of thermal energy may include heat from an infrared heater and heat from a laser.

The application of light or heat energy can be done under various conditions. For example,
When the polyimides used are the above-mentioned polyimides 1 and 3, it is preferable to expose them to the atmosphere having a humidity of 20% or more during or immediately after the application of light or heat energy. Also,
When the polyimide used is the polyimide 4,
It is preferred to apply light or heat energy in an atmosphere of halogen, such as bromine.

The mechanism by which the polyimide of the alignment film changes its surface energy upon application of light or heat energy depends on the specific functional group contained in the polyimide molecule, as described above. That is, as described below with reference to typical examples, the surface energy is changed as a result of the long chain of the polyimide being changed as described in the presence of light or heat. Reaction formula 1:

[0021]

[Chemical 1]

Reaction formula 2:

[0023]

[Chemical 2]

Reaction formula 3:

[0025]

[Chemical 3]

Reaction formula 4:

[0027]

[Chemical 4]

Reaction formula 5:

[0029]

[Chemical 5]

In the above formula, R ₁ and R ₂ each represent an arbitrary group located at the terminal of the polyimide, and specifically include, for example, the groups listed below.

[0031]

[Chemical 6]

Here, R ₁ and R ₂ may each contain an imide group or an amic acid group. The polyimide used in the present invention is not particularly limited as long as it can participate in the reaction as described above, but in selecting the polyimide, consider the factors such as the structure and performance of the liquid crystal display device and the manufacturing process. is necessary. Examples of suitable polyimides in the present invention are described below.

[0033]

[Chemical 7]

In the above formula, R ₃ and R ₄ can each have a structure as shown in Table 1 below, and n is an integer of several tens to several tens of thousands.

[0035]

[Table 1]

Further, in the present invention, instead of using polyimide as the material for the alignment film, polyamic acid which is its precursor may be used. That is, the polyamic acid is synthesized by reacting a diamine compound and an acid anhydride in a suitable solvent, and when light or heat energy is applied to the polyamic acid to effect dehydration ring closure, it becomes a polyimide. An example of the reaction in this case is as follows. Reaction formula 6:

[0037]

[Chemical 8]

As described above, the single alignment film included in the liquid crystal display panel of the present invention comprises an aggregate of two adjacent minute regions, and is continuously rubbed in one direction along the minute regions. In addition, the pre-tilt angles are different from each other in the minute area. Here, in order to make the pretilt angles of the liquid crystals contacting the alignment film in the two minute regions different from each other, it is recommended to perform a treatment different from the rubbing. Examples of the treatment different from the rubbing include, for example, selectively irradiating light such as ultraviolet rays, selectively heating with a heat source such as an infrared heater and a laser, and after applying the alignment film material. Prior to rubbing, it is possible to selectively pre-cure (pre-cure) a minute region so that the solvent evaporation time changes. In addition, as other usable processes, the shape (surface area) of the surface of the minute region is selectively changed, for example, unevenness is increased on the surface of one region, and the pretilt angle of the surface of the minute region is controlled. Selectively changing the concentration distribution of the chemical components to be formed, for example, intentionally cutting and removing the surface portion of one of the minute regions, selectively changing the hydrophobicity between the substrate and the alignment film, It is possible to selectively attach a material layer for increasing or decreasing the pretilt angle to the surface.

In the practice of the present invention, the structure of the liquid crystal display panel, the members used therein (including the liquid crystal substance sandwiched between the substrates), the manufacturing process thereof and the like can all be based on known ones. The description will be made with reference to a typical example. The details of the present invention are described in the examples described below with reference to the accompanying drawings. Before that, the outline of the liquid crystal display panel of the present invention will be described as follows.

The liquid crystal display panel according to the present invention comprises a first substrate 1 having an alignment film 26, as shown in cross section in FIG.
8, a second substrate 16 facing the first substrate and having an alignment film 22, and a liquid crystal 20 inserted between the first and second substrates, at least the first substrate 16. The alignment film 22 on the substrate is made of a single alignment film (hereinafter also referred to as an alignment material layer) having first and second adjacent minute regions A and B. The single alignment film is composed of the first and second minute regions A and B.
Is continuously rubbed in one direction along, and the rubbing is preferably performed so that the pretilt angles α and γ of the liquid crystals contacting the alignment film in the first and second minute regions A and B are different from each other. Processing different from is performed.

In the method of manufacturing a liquid crystal display panel as described above, a treatment different from the rubbing which is performed so that the pretilt angles α and γ of the liquid crystals contacting the first and second regions A and B are different from each other is performed. As described above, the first and second regions A and B are selectively irradiated with light (for example, ultraviolet rays), and the chemical components that control the pretilt angle of the surface of the first and second regions A and B. Selectively changing the concentration distribution of, the first and second regions A and B are selectively heated, and the like.

In the above structure, the alignment film 26 of the first substrate has the same liquid crystal alignment direction and pretilt angles α and γ.
Have first and second adjacent minute regions A and B which are different from each other. Regarding the second substrate, for example, the orientation film 22 of the second substrate has the orientation direction and the pretilt angle β of the first.
And the second adjacent minute regions A and B may be substantially the same, and α>β> γ. In the above structure, the alignment films on the first and second substrates both have a single-layer structure, which makes the structure simpler than the conventional structure.
The second substrate also has the same orientation direction of the liquid crystal and different first and second pretilt angles α and γ.
Can have minute regions B and A adjacent to each other.

In the case of α>β> γ, in the first area A, the pretilt angle of the liquid crystal in contact with the first substrate is α, and the pretilt angle of the liquid crystal in contact with the second substrate is β. . In the second region B, the pretilt angle of the liquid crystal in contact with the first substrate is γ, and the pretilt angle of the liquid crystal in contact with the second substrate is β. The liquid crystal molecules located between the first substrate and the second substrate have the first liquid crystal molecules when the voltage is applied.
Has a property of rising in accordance with the larger pretilt angle of the first substrate and the second substrate. In the first region A, the rising (tilt) follows the direction of the liquid crystal in contact with the first substrate, and in the second region B. In (1), rising (tilt) follows the direction of the liquid crystal in contact with the second substrate, and pixel division can be achieved.

The liquid crystal display panel shown in FIG. 4 can be manufactured through a series of steps shown by a flow sheet in FIG. That is, after the substrate is charged, the alignment film material is applied, and the obtained alignment film is selectively exposed or heated,
Minute regions A and B having different pretilt angles are formed. For example, when ultraviolet rays from a high pressure mercury lamp are used, selective exposure is performed with a photomask interposed between the mercury lamp and the alignment film. As a result of the selective exposure, a low pretilt angle β is obtained in the exposed portion (second region B),
Further, a high pretilt angle α is obtained in the non-exposed portion (first area A). After forming a desired minute region in the alignment film, a rubbing process is performed, a spacer is applied,
The substrates are bonded together, liquid crystal is injected, the liquid crystal injection port is sealed, and then a polarizing plate is applied to complete the panel. As will be readily appreciated, this manufacturing process is significantly shorter and simpler than that of the prior art described with reference to FIG. In particular, it is noteworthy that the photo process and the wet process, which are required in the conventional process, are not necessary, and the time and cost can be greatly reduced.

[0045]

In the present invention, in order to solve the problems in the alignment division process, attention is paid to the molecular structure of the polyimide used as the alignment film material, and by using the polyimide having a specific functional group in the molecule, light or It is possible to divide the alignment region by irradiation of thermal energy. In particular, by considering the introduction of a specific functional group from the stage of designing the polyimide molecule, it is possible to more easily and reliably divide the alignment region. Further, according to the present invention,
A stable, low-cost, high-yield alignment division type liquid crystal display panel can be obtained without worrying about damage to the alignment film.

[0046]

EXAMPLE Referring again to FIG. FIG. 4 shows the first of the present invention.
It is a figure which shows the liquid crystal display panel 10 for liquid crystal display devices of an Example. Polarizing plates 12 and 14 are provided on both sides of the liquid crystal panel 10.
Are arranged in a vertical relationship when in normally white mode, or in a parallel relationship when in normally black mode.

The liquid crystal panel 10 has a liquid crystal 20 enclosed between a pair of transparent glass substrates 16 and 18. Light from a light source (not shown) is directed to the liquid crystal panel 1 from the direction of arrow L.
0, and the viewer views the liquid crystal panel 10 from the direction opposite to the incident direction. In the following description, the substrate 16 on the light incident side will be referred to as the lower substrate, and the substrate on the viewer side will be referred to. 18
Will be called the upper substrate. However, the light incident side and the viewer side can be reversed.

The common electrode 2 of ITO is formed on the inner surface of the lower substrate 16.
1 and the alignment film 22 are provided, and the pixel electrode 24 and the alignment film 26 are provided on the inner surface of the upper substrate 18. A color filter layer (not shown) is provided below the common electrode 21 of the lower substrate 16. The common electrode 21 and the pixel electrode 24 can be provided in reverse. As shown in FIG. 6, the pixel electrode 24 provided on the upper substrate 18 is connected to the active matrix circuit. The active matrix circuit includes data bus lines 30 and gate bus lines 32 extending vertically and horizontally in a matrix, and the pixel electrodes 24 are connected to the data bus lines 30 and gate bus lines 32 via thin film transistors (TFTs) 34. .

As shown in FIG. 6, each pixel area represented by the pixel electrode 24 is divided into two minute areas A and B. The division pattern shown in FIG. 6 has a stripe shape formed by a line passing through the centers of the pixel electrodes 24 arranged in one horizontal line. For example, two minute regions A and B are alternately arranged in the pixel electrodes 24 arranged in one horizontal line. It can also be a staggered pattern.

In the illustrated example, the liquid crystal 20 is a twisted nematic (TN) liquid crystal. The rubbing basics and the alignment division basics when the twisted nematic liquid crystal is used will be described with reference to the accompanying FIGS. 7 to 13. FIG. 7 shows an example of a rubbing process when a twisted nematic liquid crystal (without alignment division) is used, a solid arrow 22a indicates a rubbing direction applied to the alignment film 22 of the lower substrate 18, and a broken arrow. Reference numeral 26a indicates the rubbing direction applied to the alignment film 26 of the upper substrate 16.

FIG. 8 shows liquid crystal molecules 20 in contact with the alignment film 22 of the lower substrate 16 when the rubbing treatment as shown in FIG. 7 is performed.
L and liquid crystal molecules 20U in contact with the alignment film 26 of the upper substrate 18
And the liquid crystal molecules 20C located between the lower substrate 16 and the upper substrate 18 are shown separately. In FIG. 8, the drawing on the left side of each step is a plan view showing the alignment direction of the liquid crystal molecules seen corresponding to FIG. 7, and the drawing on the right side of each step is a cross-sectional view seen from the direction of the arrow in the left figure. is there. Lower substrate 16
The alignment direction of the liquid crystal molecules 20L in contact with the alignment film 22 is aligned with the rubbing direction 22a of the alignment film 22 of the lower substrate 16 and is downward to the right. The alignment of the liquid crystal molecules 20U in contact with the alignment film 26 of the upper substrate 18 is aligned. The orientation is the alignment film 2 of the upper substrate 18.
6 corresponds to the rubbing direction 26a of 6 and faces upward to the left. The liquid crystal is twisted counterclockwise between the lower substrate 16 and the upper substrate 18, and the liquid crystal molecules 20C in the middle are in a uniform orientation in which the liquid crystal molecules 20C are directed to the upper left.

FIG. 9 is a sectional view of the rubbing-processed liquid crystal panel 10 shown in FIG. 7, taken along the line segment XX-XX in FIG. The arrow C indicates that the liquid crystal panel 10 is viewed from the normal direction of the upper substrate 18, the arrow U indicates that the liquid crystal panel 10 is viewed at an angle of 30 degrees obliquely upward, and the arrow L indicates that the liquid crystal panel 10 is obliquely downward 30 degrees. It shows to see from the direction.

FIG. 10 is a diagram showing the viewing angle characteristics of the liquid crystal panel 10 after the rubbing treatment shown in FIG. In the figure,
A chain line C is a voltage-transmittance curve when the liquid crystal panel 10 is viewed from the direction of arrow C in FIG. Broken lines U and L are voltage-transmittance curves when the liquid crystal panel 10 is viewed from the directions of arrows U and L in FIG. 9, respectively. In the case of the broken line L, since the decrease in the transmittance is small even if the voltage is increased, even if an attempt is made to obtain a black display, the display becomes relatively bright. In the case of the broken line U, when the voltage is slightly applied, the transmittance is significantly reduced, and an image with a large contrast ratio is obtained, but the transmittance is increased again as the voltage is increased, and the correspondence relationship between the voltage and the transmittance is increased. It can be inconvenient to invert and get an intermediate color between white and black.

In order to improve such viewing angle characteristics, pixel division as shown in FIG. 11 is performed. FIG. 11 shows
A basic form of pixel division having a minute area A and a minute area B is shown. In this minute area A, the same rubbing process as in FIG. 7 is performed. In the minute area B, the rubbing process opposite to that in the minute area A is performed. That is, the direction of the broken arrow 26a of the minute region B is the direction of the broken arrow 26a of the minute region A.
Is opposite to the direction of the arrow, and the solid line arrow 22a of the minute area B
Is opposite to the direction of the solid arrow 22a of the minute area A. As a result, the liquid crystal molecules 20C located between the lower substrate 16 and the upper substrate 18 of the minute region B face the opposite of those of the minute region A, and the viewing angle characteristics are also reversed.

When such a minute area A and a minute area B are arranged adjacent to each other, when the liquid crystal display panel 10 is viewed from the direction of the arrow U or L in FIG. 9, the characteristic indicated by the solid line I in FIG. 10 is obtained. . The characteristics of the solid line I are those obtained by adding the characteristics of the broken line L and the broken line U and dividing by 2, and are close to the characteristics of the alternate long and short dash line C seen from the normal direction, and are extremely high in the viewing angle direction where the transmittance is extremely high. The viewing angle direction with low transmittance is eliminated, and the viewing angle characteristics are improved. This is the effect of pixel division. But,
In order to perform the rubbing process shown in FIG. 11, it is necessary to perform rubbing twice for each substrate, as described above. Such a process is troublesome, and therefore, the applicant of the present application first invented the alignment process, an example of which is shown in FIGS. 12 and 13, as described in the specification of Japanese Patent Application No. 212722 of 1993. , Filed a patent application (hereinafter referred to as a prior application).

In FIG. 12, the rubbing process for the minute region A is the same as the rubbing process for the minute region B.
That is, the alignment film 22 of the lower substrate 16 may be rubbed in the direction of arrow 22a through the minute regions A and B, and the alignment film 26 of the upper substrate 18 may be rubbed in the direction of arrow 26a through the minute regions A and B. You can do rubbing on. However, it is necessary to set the pretilt angle of the liquid crystal as shown in FIG.

In FIG. 13, the alignment film 2 of the lower substrate 16 is formed.
Reference numeral 2 is a one-layered structure in which the pretilt angle of the liquid crystal in contact with the rubbing is β when the rubbing is performed. The alignment film 26 of the upper substrate 18 has a two-layer structure including a lower alignment material layer 51 and an upper alignment material layer 52, and the upper alignment material layer 52 corresponds to a minute region A or B. And is patterned so as to open. The upper alignment material layer 52 is made of a material in which the pretilt angle α of the liquid crystal in contact with the alignment material layer 52 is relatively large when rubbed.
The lower alignment material layer 51 is made of a material having a relatively small pretilt angle γ of the liquid crystal in contact with the alignment material layer 51 when it is rubbed. Here, there is a relationship of α>β> γ.

Then, in the minute region A, the pretilt angle of the liquid crystal molecules on the lower substrate 16 side is β, and the upper substrate 1
The pretilt angle of the liquid crystal molecules on the 8 side is γ, and β> γ. In the minute region B, the pretilt angle of the liquid crystal molecules on the lower substrate 16 side is β, the pretilt angle of the liquid crystal molecules on the upper substrate 18 side is α, and α> β. In the prior application, the inventors of the present application, if there is such a certain difference in the pretilt angle between the upper and lower sides, the liquid crystal molecules 20C in the middle between the lower substrate 16 and the upper substrate 18 have the same pretilt angle when the voltage is applied. Stand up according to the larger rubbing (tilt)
I found that. It has been found that the light transmission characteristics of the liquid crystal are mainly determined by the behavior of the intermediate liquid crystal molecule 20C.

Therefore, in FIG. 13, the liquid crystal molecules 20C in the middle of the minute region A rise in the rubbing direction of the alignment film 22 of the lower substrate 16. The rubbing direction of the alignment film 22 of the lower substrate 16 of FIG.
2a, and this is the same as the rubbing direction 22a of the minute area A in FIG. Therefore, the viewing angle characteristics of the minute area A in FIGS. 12 and 13 are the same as the viewing angle characteristics of the minute area A in FIG. 11.

Similarly, the liquid crystal molecules 20C in the middle of the minute region B of FIG. 13 are aligned according to the rubbing direction of the alignment film 26 of the upper substrate 18. The alignment film 26 of the upper substrate 18 of FIG.
11 corresponds to the rubbing direction 26a of FIG. 12, and this is the same as the rubbing direction 26a of the minute region B of FIG. Therefore, the viewing angle characteristics of the minute area B in FIGS. 12 and 13 are the same as the viewing angle characteristics of the minute area B in FIG. 11. That is, the same effect of pixel division as that of FIG. 11 can be achieved by the processing of FIG. 12 and FIG.
13 is simpler in manufacturing because the rubbing is performed once for each substrate, and the alignment of the liquid crystal is stable.

The present invention further improves on this earlier application, and FIG.
As shown in FIG. 3, for example, the alignment film 26 of the upper substrate 18 has a single layer structure so that different pretilt angles α and γ can be realized for each of the minute regions A and B.
Further, as shown in FIG. 14, the upper substrate 18 and the lower substrate 1
It is also possible to form the alignment films 26 and 22 of No. 6 as a single layer structure to form different pretilt angles α and γ for each of the minute regions A and B. In the case of this modification, the pretilt angles α and γ are opposed to each other at the top and bottom. Hereinafter, the configuration of FIG. 4 will be mainly described.

In the liquid crystal display panel of the present invention, as shown in FIG. 12, the single-layer alignment film 26 is continuously rubbed in one direction along the two minute regions A and B, and As described in, two small areas A,
In B, a treatment different from the rubbing is performed so that the pretilt angles α and γ of the liquid crystal contacting the alignment film 26 are different from each other.

FIGS. 15A to 15C are cross-sectional views sequentially showing a first embodiment of the process of making the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18 different. In FIG. 15, first, in step (a), the alignment film 26 is applied to the surface of the upper substrate 18 by spin coating. Here, to apply the alignment film 26 on the surface of the upper substrate 18 means to apply the alignment film 26 to the surface of the pixel electrode 24 or other material if it is formed on the upper substrate 18. is there. The alignment film 26 is made of polyimide having a high pretilt angle and an imidization ratio of 100%. This kind of polyimide is usually called soluble polyimide, and various kinds of polyimide components are dissolved in a solvent. The polyimide component includes a chemical component such as a diamine component, which particularly controls the pretilt angle. As such an aligning material, for example, JALS219, 214 manufactured by Japan Synthetic Rubber can be used.

In FIG. 15B, the alignment film 26 of the upper substrate 18 is cured in an oven or the like to remove the solvent and cure the alignment film 26. Then, in FIG.
In (c), the minute regions A and B are formed using the mask 60.
And selectively irradiate it with ultraviolet rays. The mask 60 includes a plate 60a made of a material made of quartz or synthetic quartz that transmits ultraviolet rays, and an ultraviolet blocking material layer 60b of chromium or the like provided on the plate corresponding to one of the minute regions A and B. Consists of.

Next, in FIG. 15D, the alignment film 26 is rubbed by using a rubbing roller 57. 12
Rubbing as shown in is possible. 16A to 16C are cross-sectional views sequentially showing a second embodiment of the process of making the liquid crystal pretilt angles α and γ of the alignment film 26 of the upper substrate 18 different.
In this embodiment, as in the embodiment of FIG.
In step (b), the alignment film 26 is applied to the surface of the upper substrate 18, and in step (b), the alignment film 26 of the upper substrate 18 is cured. Next, contrary to the embodiment of FIG. 15, the alignment film 26 is rubbed in step (c), and the minute regions A and B are selectively irradiated with ultraviolet rays using the mask 60 in step (d).

In FIG. 15 and FIG. 16, by selectively irradiating the minute regions A and B with ultraviolet rays, the minute regions A not irradiated with ultraviolet rays have the properties of the polyimide used as the alignment film material. Depending on and following rubbing before and after that, a high pretilt angle α is exhibited. On the other hand, in the minute region B irradiated with ultraviolet rays, the surface energy of the alignment film 26 in that portion increases, and the pretilt angle γ is smaller than that in the case where predetermined rubbing is performed depending on the property of the initial polyimide. Become. Thereby, for example, the pretilt angle α is 8 degrees, the pretilt angle β is 4 degrees,
It is possible to make a combination in which the pretilt angle γ is 1 degree.

The fact that the pretilt angle γ is reduced by irradiating with ultraviolet rays is shown in the relationship (graph) of FIGS. 17 and 18. As shown in FIG. 17, the pretilt angle becomes smaller as the irradiation time of ultraviolet rays becomes longer. The irradiation of ultraviolet rays increases the surface energy of the alignment film 26, but as shown in FIG. 18, the greater the surface energy of the alignment film 26, the better the wettability of the alignment film 26 and the lower the contact angle. ， And the pretilt angle becomes smaller. The experimental fact that the higher the surface energy of the alignment film 26, the smaller the pretilt angle is used in the examples described below.

In order to reduce the pretilt angle by utilizing the irradiation of ultraviolet rays, it is necessary to use ultraviolet rays having energy enough to break the polyimide bond on the surface of the alignment film 26. For this purpose, it is desirable to use ultraviolet rays having a wavelength of 300 nm or less, and it is more preferable to use ultraviolet rays having a wavelength of 260 nm or less. In the examples, mainly 253.7 nm and 184.9n
10mW low-pressure mercury lamp that generates ultraviolet rays of wavelength m
Used at / cm ² .

FIG. 19 is a schematic view showing an example of obtaining a combination of the alignment film 26 of the upper substrate 18 and the alignment film 22 of the lower substrate 16 as shown in FIG. 4 by utilizing ultraviolet irradiation. In this embodiment, as the alignment film 26 of the upper substrate 18 and the alignment film 22 of the lower substrate 16, the same alignment film material is used so that the liquid crystals show similar pretilt angles when the same rubbing treatment is performed. ing.

FIG. 19A shows the alignment film 26 of the upper substrate 18.
The orientation treatment of is shown. First, the entire surface is rubbed by the rubbing roller 57 so that the liquid crystal in contact with the alignment film 26 has the pretilt angle α. Then, the mask 60 is used to irradiate with ultraviolet rays so that the pretilt angle is kept at α in the minute area B not exposed to the ultraviolet rays, and the pretilt angle is set to γ in the minute area A exposed to the ultraviolet rays. Note that rubbing and ultraviolet irradiation may be performed in the reverse order.

FIG. 19B shows the alignment film 22 on the lower substrate 16.
The orientation treatment of is shown. First, the entire surface is rubbed by the rubbing roller 57 so that the liquid crystal in contact with the alignment film 26 has the pretilt angle α. Next, unlike FIG. 19A, ultraviolet rays are irradiated without using a mask, so that the pretilt angle becomes β. Also in this case, rubbing and ultraviolet irradiation may be performed in the reverse order. In this way, the alignment films 22 and 26 satisfying the relationship of α>β> γ can be obtained.

FIG. 20 is a schematic view showing another embodiment of the combination of the alignment film 26 of the upper substrate 18 and the alignment film 22 of the lower substrate 16. FIG. 20A shows the alignment treatment of the alignment film 26 on the upper substrate 18. First, the entire surface is rubbed by the rubbing roller 57, and the liquid crystal in contact with the alignment film 26 has a pretilt angle α.
So that Then, the mask 60 is used to irradiate with ultraviolet rays so that the pretilt angle is kept at α in the minute area B not exposed to the ultraviolet rays, and the pretilt angle is set to γ in the minute area A exposed to the ultraviolet rays.

FIG. 20B shows the alignment film 22 on the lower substrate 16.
The orientation treatment of is shown. Here, the liquid crystal in contact with the alignment film 26 is rubbed so as to have a pretilt angle β. In this case, the same material may be used as the film material of the alignment film 26 and the alignment film 22, or different materials may be used. In short, the pretilt angle is made different depending on the combination of the alignment film material and the rubbing. When the same film material is used, the number of times of rubbing is increased or decreased so that the pretilt angle is different. And in this case as well, α> β
It is necessary to satisfy the relation of> γ.

FIG. 21 is a sectional view showing a modified example of the mask 60 used to make the pretilt angles α and γ different by the irradiation of ultraviolet rays in the above example. Mask 60
Is a plate 60a made of quartz or synthetic quartz that transmits ultraviolet rays, and an ultraviolet ray blocking material layer 60b made of chromium that blocks ultraviolet rays is attached to the plate 60a. In this variation,
The plate 60a that transmits ultraviolet rays has a protrusion 60c, and the ultraviolet blocking material layer 60b is attached to the surface of the protrusion 60c. Therefore, the surface of the ultraviolet blocking material layer 60b is projected more than the surface 60d of the portion of the plate 60a that transmits ultraviolet rays between the ultraviolet blocking material layers 60b.

According to this structure, the ultraviolet blocking material layer 60
Ultraviolet irradiation can be performed by bringing b to the alignment film 26 of the upper substrate 18 as close as possible or in contact with it. By doing so, it is possible to prevent the ultraviolet rays from entering the region below the ultraviolet blocking material layer 60b when the ultraviolet rays are obliquely incident on the mask 60, as shown by the arrow P. If the ultraviolet blocking material layer 60b is at the position shown by the broken line 60e, the ultraviolet rays shown by the arrow P will wrap around the ultraviolet blocking material layer 60e and enter the region of the alignment film 26 where the ultraviolet blocking is desired. Not preferable.

When the plate 60a is flat, the plate 6 is used to prevent ultraviolet rays from wrapping around the ultraviolet blocking material layer 60e.
It is desirable that the entire surface 0a be close to the alignment film 26 as much as possible, but then the surface 60d of the portion of the plate 60a that is opened between the ultraviolet blocking material layers 60b is too close to the alignment film 26. The surface 60d of the opening of the mask 60 and the upper substrate 18
It was found that when the gap between the alignment film 26 and the alignment film 26 was small, the amount of ozone generated in the gap was small, and the effect of modifying the surface of the alignment film 26 by ultraviolet irradiation was reduced. That is, FIG. 22 shows a gap between the surface 60 d of the opening portion of the mask 60 and the alignment film 26 of the upper substrate 18,
6 is a graph showing the relationship with the surface energy of the alignment film 26 (related to the pretilt angle). As shown,
The smaller the gap between the mask and the substrate, the smaller the surface energy of the alignment film 26. Therefore, it is desirable that the ultraviolet blocking material layer 60b be as close as possible to the alignment film 26 so that there is an appropriate gap between the surface 60d of the opening and the alignment film 26 of the upper substrate 18.

FIG. 23 is a sectional view showing a modification of the mask shown in FIG. In this example, the ultraviolet ray blocking material layer 60b attached to the ultraviolet ray transmitting plate 60a of the mask 60 is made relatively thick, so that the same action as that of FIG. 21 is performed. In this case, the ultraviolet blocking material layer 60b is preferably made of an ultraviolet light blocking resin.

FIG. 24 shows the mask of FIG.
It is sectional drawing which shows one modification. In this example, the mask 6
A plate 60a that transmits 0 ultraviolet rays and an ultraviolet blocking material layer 60
A spacer 60f is provided between the spacer b and b, so that the same operation as that of FIG. 21 is performed. In this case, the ultraviolet blocking material layer 60b is made of chrome, and the spacer 60
f consists of a suitable resin.

FIG. 25 is a cross-sectional view showing in sequence the third embodiment of the process of making the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18 different. In this example, selective change of the concentration distribution of the chemical component that controls the pretilt of the surfaces of the minute regions A and B will be described. In FIG. 25, the alignment film 26 is applied to the surface of the upper substrate 18 in the step (a), the alignment film 26 of the upper substrate 18 is cured in the step (b), and the resist is formed on the alignment film 26 in the step (c). A mask 54 is formed to slightly etch the surface of the portion corresponding to the minute region A of the alignment film 26, and the alignment film 26 is rubbed with a rubbing roller 57 in step (d) as shown in FIG.

FIG. 14 is an enlarged sectional view showing a part of the alignment film 26 etched in the step (c) of FIG. The material of the alignment film 26 made of polyimide is usually referred to as soluble polyimide as described above, and various kinds of polyimide components are dissolved in a solvent. The polyimide component includes a chemical component such as a diamine component that particularly controls the pretilt angle and a chemical component that does not significantly affect the pretilt angle. The chemical component that governs the pretilt angle is usually hydrophobic and tends to concentrate on the surface of the film in a low humidity atmosphere such as air or nitrogen. When the temperature of the precure in the curing of the alignment film 26 is performed as low as possible, the chemical components that govern the pretilt angle are concentrated on the surface.

In FIG. 26, the hatching shows that the chemical components governing the pretilt angle are concentrated on the surface of the alignment film 26. When the surface of the alignment film 26 in which the chemical components controlling the pretilt angle are concentrated is selectively changed, a portion containing a large amount of the chemical components controlling the pretilt angle and a portion free of such components are formed. As a result, the pretilt angles α and γ of the liquid crystal can be made different. In the illustrated embodiment, the alignment film 26
26 is used as a means for changing the shape of the surface, and in FIG. 26, the surface portion 26x corresponding to the minute region A of the alignment film 26 is slightly cut and removed by the etching in the step (c) of FIG. . The adjacent minute region B contains a large amount of chemical components that control the pretilt angle. In order to reduce the damage caused by the developing solution at the time of resist patterning, it is preferable to perform the post-curing in the curing of the alignment film 26 as high as possible (for example, about 300 ° C.) (the alignment film material is Nippon Synthetic Rubber Co., Ltd. In the case of JALS-214 manufactured by
300 ° C). When a polyamic acid type polyimide is used, since it has relatively high chemical resistance, it is possible to keep the curing temperature at 200 ° C. or lower (for example, CRD4 manufactured by Sumitomo Bakelite Co., Ltd.).
022).

Further, FIG. 27 shows an alignment film 26 between the upper substrate 18 and the alignment film 26 as a means for selectively changing the distribution of the chemical components that govern the pretilt angle of the surfaces of the minute regions A and B. An example is shown in which a process for selectively changing the hydrophobicity of is used. More specifically, the amorphous silicon layer 61 is used as a base of the alignment film 26 in a region corresponding to the minute region A. Amorphous silicon without a surface oxide film exhibits hydrophobicity. Therefore, in the alignment film 26 that is in contact with the amorphous silicon layer 61 in the minute region A, the chemical components that control the pretilt angle are concentrated near the amorphous silicon layer 61, and the alignment film 2 as a whole.
On the surface side of 6, the chemical components that dominate the pretilt angle are small. In FIG. 27 as well, as in FIG. 26, the portion where the chemical components governing the pretilt angle are concentrated is shown by hatching. It can be seen that the adjacent minute region B contains a large amount of chemical components that control the pretilt angle.

FIG. 28 is a cross-sectional view showing in sequence the process of making the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18 different from each other in the fourth embodiment. In this example, selective deposition of a material layer for increasing or decreasing the pretilt angle on the surfaces of the minute regions A and B will be described. More specifically, the step of depositing the material layer for increasing / decreasing the pretilt angle includes the step of selectively depositing the material layer having the property of aligning the liquid crystal in the direction perpendicular to the substrate surface.

In FIG. 28, the alignment film 26 is applied on the surface of the upper substrate 18 in the step (a), the alignment film 26 of the upper substrate 18 is cured in the step (b), and the upper substrate 18 in the step (c). Is housed in the chamber 63,
Nitrogen gas containing 1000 ppm of siloxane gas is introduced into the chamber 63 to adhere the siloxane to the alignment film 26, and in the step (d), the alignment film 26 is rubbed using the rubbing roller 57 as shown in FIG.

Prior to the step (c), a resist mask 54 is formed on the alignment film 26, and a minute area A of the alignment film 26 is formed.
And the micro area B is covered.
The part corresponding to is exposed. Therefore, step (c)
In, the siloxane adheres to the portion corresponding to the minute region B of the alignment film 26. Siloxane is known as a material having a property of orienting liquid crystal in a direction perpendicular to the substrate surface, and therefore the pretilt angle of the liquid crystal in the minute region B is larger than that in the minute region A to which siloxane is not attached. It will be -10 degrees. In this case, the alignment film material has a pretilt angle of 1 to 2 by a normal rubbing treatment.
The pretilt angle of the minute area A is 1 to 2 degrees. When the alignment film 26 is left for 10 minutes in nitrogen gas containing 1000 ppm of siloxane,
The pretilt angle of the minute area B is 6 to 7 degrees. In addition,
Instead of treating the alignment film 26 in a siloxane gas, the alignment film 26 can be dipped in a siloxane solution.

FIGS. 29A to 29C are sectional views sequentially showing a fifth embodiment of the process of making the pretilt angles α and γ of the liquid crystal of the alignment film 26 of the upper substrate 18 different. In this embodiment, the step of selectively heating the minute regions A and B is included. In FIG. 29, the alignment film 26 is applied to the surface of the upper substrate 18 in the step (a), the alignment film 26 of the upper substrate 18 is cured in the step (b), and the rubbing roller 57 is used in the step (c). The alignment film 26 is rubbed as shown in FIG. 12, and in step (d), the alignment film 26 is selectively heated from a heat source such as an infrared heater through the mask 65 (for example, heated to 200 ° C.). When the alignment film 26 is rubbed, the pretilt angle of the liquid crystal contacting the alignment film 26 is α
If the micro area A is heated using an infrared heater after rubbing, the trace of rubbing on the alignment film 26 will be slightly alleviated, and the pretilt angle will decrease from α to γ.

FIG. 30 is a perspective view showing an infrared heater 66 which can be used as the heating means of FIG. In this case, the mask 65 has a portion 65a for transmitting heat,
It has a comb-teeth shape having a heat-shielding portion 65b. The heat-transmitting portion 65a and the heat-shielding portion 65b are each substantially half the pixel pitch.

FIG. 31 is a perspective view showing a laser source 67 that can be used as the heating means in FIG. In the figure,
A scanning means for selectively scanning the laser beam emitted from the laser source 67 is also shown. The laser beam scanning means is composed of a polygon mirror 68, which is rotatable about its own axis and scans the laser beam in the width direction (Y direction) of the minute area A to be heated. Further, the laser source 67 and the polygon mirror 68 are movable in the length direction (Z direction) of the minute area A to be heated. Therefore, the minute area A can be heated in a band shape.

FIG. 32 is a cross-sectional view sequentially showing a sixth embodiment of the process of making the liquid crystal pretilt angles α and γ of the alignment film 26 of the upper substrate 18 different. In this embodiment, after the alignment film 26 is applied to the upper substrate 18 in the step (a), the minute regions A and B are selectively pre-cured so that the solvent volatilization time is changed in the step (b). At the time of pre-cure, the upper substrate 18 is placed on the hot plate 69 and heated by an infrared heater from above. The mask 65 is used to positively heat only the minute area A while blocking the minute area B.

The pretilt angle changes due to the precure process. As shown in FIG. 33 as the relationship between the curing temperature and the pretilt angle, the lower the precure temperature (the longer the precure time), the larger the pretilt angle. Therefore, after completion of the pre-cure, post-cure is performed in step (c), and step (d)
When the rubbing is performed in (1), the pretilt angle of the minute region B pre-cured while being shielded by the mask 65 becomes α, and the pretilt angle of the minute region A becomes γ.

FIG. 33 shows a modification of the precure shown in FIG. That is, in this modification, the step (b) of FIG.
In Section 2, instead of selectively heating the alignment film 26 of the upper substrate 18 with the infrared heater, selectively cooling the alignment film 26 of the upper substrate 18 will be described. However, since the upper substrate 18 is placed on the hot plate 69, it is heated as a whole, and the cold air used is for adjusting the precure temperature.

Example 1 After washing a TFT substrate and a CF substrate with running water, a polyimide containing a ketone group was treated with N-methylpyrrolidone (NM).
The solution obtained by dissolving in P) was applied by a printing machine. The coating film on the substrate is heated at 120 ° C. for 1 minute to be pre-baked, then 18
It was baked by heating at 0 ° C. for 1 hour. The thickness of the obtained alignment film was 500Å. Then, the substrate is mounted on a proximity exposure machine, and the alignment film is irradiated with ultraviolet rays having a wavelength of 300 nm or more at an energy amount of 1000 mJ / cm ² through a photomask,
The alignment film was selectively modified. After the ultraviolet irradiation, the substrate was left in the atmosphere having a humidity of 20% or more for 1 minute. At this time, the long-chain portion of the polyimide molecule reacted with water molecules in the atmosphere to change the molecular structure (see the reaction formula 1). As a result, the surface energy of the alignment film was changed, and it was possible to obtain an alignment division type liquid crystal display panel having minute regions having different pretilt angles.

As a modification, the above method was repeated, except that the wavelength of ultraviolet rays used for the selective exposure of the alignment film was changed to less than 300 nm. In addition to the above reaction of the polyimide, a decomposition reaction of the long chain portion of the polyimide molecule occurred. As a result, the surface energy of the alignment film was further changed, and alignment regions having different pretilt angles were formed.

Example 2 The procedure described in Example 1 above was repeated. However, in this example, the following polyimide was used as the alignment film material instead of the polyimide containing a ketone group. -Polyimide containing peroxide-Polyimide containing ester-Polyimide containing amine-Polyimide containing amide Each of the above-mentioned polyimides has different pretilt angles by reacting with water, oxygen or hydrogen contained in the atmosphere. An alignment film having a micro region having

As a modification, the above method was repeated, except that the wavelength of ultraviolet rays used for the selective exposure of the alignment film was changed to a wavelength of less than 300 nm. In addition to the above reaction of the polyimide, a decomposition reaction of the long chain portion of the polyimide molecule occurred. As a result, the surface energy of the alignment film was further changed, and alignment regions having different pretilt angles were formed.

Example 3 After washing the TFT substrate and the CF substrate with running water, a solution obtained by dissolving a polyimide containing a carbon-carbon double bond in NMP was applied by a printing machine. The coating film on the substrate was heated at 120 ° C. for 1 minute to be pre-baked, and then at 180 ° C. for 1 hour to be baked. The thickness of the obtained alignment film was 500Å. Then, the substrate is mounted on the proximity exposure machine, and the wavelength of 300 is set.
The alignment film was irradiated with ultraviolet light having a wavelength of nm or more at an energy amount of 1000 mJ / cm ² through a photomask to selectively modify the alignment film. After the ultraviolet irradiation, the substrate was left in the atmosphere having a humidity of 20% or more for 1 minute. At this time, the long-chain portion of the polyimide molecule reacted between the molecules and the molecular structure was changed (see the reaction formula 2). As a result, the surface energy of the alignment film was changed, and it was possible to obtain an alignment division type liquid crystal display panel having minute regions having different pretilt angles.

As a modification, the above method was repeated, except that the wavelength of the ultraviolet rays used for the selective exposure of the alignment film was changed to less than 300 nm. In addition to the above reaction of the polyimide, a decomposition reaction of the long chain portion of the polyimide molecule occurred. As a result, the surface energy of the alignment film was further changed, and alignment regions having different pretilt angles were formed.

Example 4 A TFT substrate and a CF substrate were washed with running water, and then a solution obtained by dissolving a polyimide containing two carbon-carbon double bonds in NMP was applied by a printing machine. 12 on the substrate
It was heated at 0 ° C. for 1 minute to be pre-baked, and then at 180 ° C. for 1 hour to be baked. The thickness of the obtained alignment film is 500.
It was Å. Next, the substrate was mounted on a proximity exposure machine, and the alignment film was irradiated with ultraviolet rays having a wavelength of 300 nm or more at an energy amount of 1000 mJ / cm ² through the photomask to selectively modify the alignment film. After the ultraviolet irradiation, the substrate was left in the atmosphere having a humidity of 20% or more for 1 minute. At this time, the long-chain portion of the polyimide molecule reacted in the molecule to change the molecular structure (see the reaction formula 3). As a result, the surface energy of the alignment film was changed, and it was possible to obtain an alignment division type liquid crystal display panel having minute regions having different pretilt angles.

As a modified example, the above method was repeated, except that the wavelength of the ultraviolet rays used for the selective exposure of the alignment film was changed to less than 300 nm. In addition to the above reaction of the polyimide, a decomposition reaction of the long chain portion of the polyimide molecule occurred. As a result, the surface energy of the alignment film was further changed, and alignment regions having different pretilt angles were formed.

Example 5 After washing the TFT substrate and the CF substrate with running water, a solution obtained by dissolving a polyimide containing a carbon-carbon double bond in NMP was applied by a printing machine. The coating film on the substrate was heated at 120 ° C. for 1 minute to be pre-baked, and then at 180 ° C. for 1 hour to be baked. The thickness of the obtained alignment film was 500Å. Then, the substrate is mounted on the proximity exposure machine, and the wavelength of 300 is set.
The alignment film was irradiated with ultraviolet light having a wavelength of nm or more at an energy amount of 1000 mJ / cm ² through a photomask to selectively modify the alignment film. After the ultraviolet irradiation, the substrate was left in the atmosphere having a humidity of 20% or more for 1 minute. At this time, the long-chain portion of the polyimide molecule reacted with water molecules in the atmosphere to change the molecular structure (see the reaction formula 4). As a result, the surface energy of the alignment film was changed, and it was possible to obtain an alignment division type liquid crystal display panel having minute regions having different pretilt angles.

As a modification, the above method was repeated, except that the wavelength of ultraviolet rays used for selective exposure of the alignment film was changed to less than 300 nm. In addition to the above reaction of the polyimide, a decomposition reaction of the long chain portion of the polyimide molecule occurred. As a result, the surface energy of the alignment film was further changed, and alignment regions having different pretilt angles were formed.

Example 6 A TFT substrate and a CF substrate were washed with running water, and a solution obtained by dissolving a polyimide containing a carbon-carbon double bond in NMP was applied by a printing machine. The coating film on the substrate was heated at 120 ° C. for 1 minute to be pre-baked, and then at 180 ° C. for 1 hour to be baked. The thickness of the obtained alignment film was 500Å. Then, the substrate was mounted on a proximity exposure machine and exposed to ultraviolet light having a wavelength of 300 nm or more at 1000 mJ / cm ² in a bromine gas atmosphere.
The alignment film was irradiated through the photomask with an energy amount of 1 to selectively modify the alignment film. At this time, the long-chain portion of the polyimide molecule reacted with the bromine molecule to change the molecular structure (see the reaction formula 5). As a result, the surface energy of the alignment film was changed, and it was possible to obtain an alignment division type liquid crystal display panel having minute regions having different pretilt angles.

As a modification, the above procedure was repeated in an atmosphere of chlorine, fluorine or iodine, but comparable results were obtained. Further, as another modification, the above-mentioned method was repeated by changing the wavelength of ultraviolet rays used for the selective exposure of the alignment film to a wavelength of less than 300 nm. In addition to the above reaction of the polyimide, a decomposition reaction of the long chain portion of the polyimide molecule occurred. As a result, the surface energy of the alignment film was further changed, and alignment regions having different pretilt angles were formed.

Example 7 The procedure described in Examples 1 to 6 above was repeated. However, in the case of this example, instead of the polyimide described in each example, the precursor polyamic acid was used as the alignment film material. A solution obtained by dissolving polyamic acid in NMP was applied on a substrate, dried, and cured by heating to obtain a polyimide. Subsequently, an alignment film was formed according to the same method as described above and selectively exposed to ultraviolet rays. Similar to the above example, the molecular structure of the polyimide molecule is changed, and thus the surface energy of the alignment film is changed, so that an alignment division type liquid crystal display panel having minute regions having different pretilt angles can be obtained. did it.

As a modified example, when selective heating was performed instead of UV exposure for selective modification of the alignment film, comparable results were obtained in all cases. The conditions of the selective heating used here are: heating device: carbon dioxide gas laser, mask: not used (direct scanning on substrate), 1
It was 000 mJ / cm ² .

[0106]

As can be understood from the above detailed description, according to the present invention, it becomes easy to select an alignment film necessary for manufacturing an alignment division type liquid crystal display panel. As a result, the photo process and the wet process, which are required in the conventional alignment division process, are not required, and it is possible to significantly reduce the time and cost. Furthermore, since damage to the alignment film can be reduced, the reliability of the liquid crystal display panel is also improved. Further, regarding the polyimide used as the alignment film material, the alignment film required for alignment division can be easily obtained by allowing a specific functional group specific to the present invention to exist from the design stage. Further, the obtained liquid crystal display panel has a simple structure and is excellent in viewing angle characteristics and contrast.

[Brief description of drawings]

FIG. 1 is a schematic view showing an alignment treatment of a conventional liquid crystal display panel.

FIG. 2 is a cross-sectional view showing a configuration of a conventional liquid crystal display panel.

FIG. 3 is a flow sheet showing a manufacturing process of a conventional liquid crystal display panel.

FIG. 4 is a cross-sectional view showing a configuration of a liquid crystal display panel of the present invention.

FIG. 5 is a flow sheet showing a manufacturing process of the liquid crystal display panel of the present invention.

FIG. 6 is a schematic view showing the arrangement of pixel electrodes.

FIG. 7 is a schematic view showing a rubbing process of a TN liquid crystal.

FIG. 8 is a schematic view showing the orientation of TN liquid crystal molecules.

9 is a cross-sectional view taken along line XX-XX in FIG.

FIG. 10 is a graph showing viewing angle characteristics of a TN liquid crystal display panel.

FIG. 11 is a schematic view showing a basic form of pixel division.

FIG. 12 is a schematic diagram showing an advanced form of pixel division.

FIG. 13 is a cross-sectional view showing a configuration of a liquid crystal display panel of the prior application.

FIG. 14 is a cross-sectional view showing a modified example of the liquid crystal display panel.

FIG. 15 is a sectional view showing a first embodiment in which the pretilt angles are different.

FIG. 16 is a sectional view showing a second embodiment in which the pretilt angles are different.

FIG. 17 is a graph showing the relationship between UV irradiation time and pretilt angle.

FIG. 18 is a graph showing the relationship between surface energy and pretilt angle.

FIG. 19 is a cross-sectional view showing an example of manufacturing upper and lower substrates by UV irradiation.

FIG. 20 is a cross-sectional view showing another example of manufacturing the upper and lower substrates by UV irradiation.

FIG. 21 is a cross-sectional view showing a modified example of a mask used for UV irradiation.

FIG. 22 is a graph showing the relationship between the mask-substrate gap and the surface energy.

FIG. 23 is a cross-sectional view showing a modified example of a mask used for UV irradiation.

FIG. 24 is a cross-sectional view showing another modified example of the mask used for UV irradiation.

FIG. 25 is a sectional view showing a third embodiment in which the pretilt angles are made different.

FIG. 26 is an enlarged cross-sectional view of a substrate.

FIG. 27 is an enlarged cross-sectional view showing a modified example of the substrate.

FIG. 28 is a sectional view showing a fourth embodiment in which the pretilt angles are made different.

FIG. 29 is a sectional view showing a fifth embodiment in which the pretilt angle is different.

FIG. 30 is a perspective view showing an example of heating means.

FIG. 31 is a perspective view showing another example of heating means.

FIG. 32 is a sectional view showing a sixth embodiment in which the pretilt angle is different.

FIG. 33 is a graph showing the relationship between the curing temperature and the pretilt angle.

FIG. 34 is a sectional view showing a modified example of the precure.

[Explanation of Codes] 10 ... Liquid crystal display panel 16, 18 ... Substrate 20 ... Liquid crystal 22, 26 ... Alignment film A, B ... Micro area

Claims (8)

[Claims] 1. A liquid crystal display panel in which a liquid crystal substance is sandwiched between substrates facing each other, wherein each of the substrates is
At least one alignment film having an alignment film applied to its inner wall is a polyimide-based film material selected from the following group: 1. Peroxide containing no ether bond in the molecule,
Polyimide containing at least one moiety selected from the group consisting of ketones, esters, amines, amides and their derivatives, and capable of causing a change in surface energy under the action of light or heat energy; A polyimide containing a carbon-carbon double bond or a carbon-carbon triple bond therein and capable of causing a change in surface energy under the action of light or heat energy; 3. Carbon-carbon double bond in the molecule Or a polyimide containing a carbon-carbon triple bond and capable of causing a change in surface energy under the action of light or heat energy; and 4. a carbon-carbon double bond or a carbon-carbon triple bond in the molecule. A layer of polyimide, which is capable of causing a change in surface energy under the action of light or heat energy in the presence of halogen; In this case, the alignment film is composed of an assembly of two adjacent micro areas, is continuously rubbed in one direction along the micro areas, and has different pretilt in the micro areas. A liquid crystal display panel having a corner (a rising angle of liquid crystal molecules from a substrate surface). 2. The liquid crystal display panel according to claim 1, wherein the light energy is ultraviolet rays from a mercury lamp. 3. The liquid crystal display panel according to claim 1, wherein the thermal energy is heat from an infrared heater or a laser. 4. The method of manufacturing a liquid crystal display panel according to claim 1, wherein a film material for forming the single alignment film is applied on a substrate, and then the fine regions are aggregated in the formed coating film. A method for manufacturing a liquid crystal display panel, which comprises applying light or heat energy corresponding to a distribution pattern of a body, and subsequently performing a rubbing treatment. 5. The manufacturing method according to claim 4, wherein the light energy is ultraviolet rays from a mercury lamp. 6. The manufacturing method according to claim 4, wherein the thermal energy is heat from an infrared heater or a laser. 7. The manufacturing method according to claim 4, wherein the method is exposed to an atmosphere having a humidity of 20% or more during or immediately after the application of light or heat energy. 8. The manufacturing method according to claim 4, wherein light or heat energy is applied in a halogen atmosphere.