JPH01233421A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To prevent escape of light from a light source without using spacers which exist in picture element parts by disposing the spacers fixed by adhesive materials having photosensitive resins which are interposed between the spacers and the oriented film formed on a substrate with electrodes and are sufficiently thinner than the size of the spacers to island shapes onto the oriented film. CONSTITUTION:The spacers 1 fixed by the adhesive materials 2 having the photosensitive resins which are interposed between the spacers 1 and the oriented film 10 formed on at least one substrate 11 with electrodes and are sufficiently thinner than the size of the spacers 1 are disposed to the island shapes on the oriented film. For example, the sealing materials 12 previously mixed with the prescribed spacers exist in the peripheral part between the front glass plate 7 attached with the transparent electrodes 5 and the oriented film 6 thereon and the substrate 11 for liquid crystal display attached with thin-film transistor element parts 8 and the picture element parts 9 and the oriented film 10 thereon. The spacers 1 are thereby fixed to the surface of the oriented film 6 except the picture element parts 9 on the substrate 11 with electrodes, by which the escape of the light, etc., are obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal display device for displaying characters or images, and more particularly to a liquid crystal display device having a substrate with electrodes on which spacers are fixed on an alignment film, and a method for manufacturing the same. It is.

BACKGROUND OF THE INVENTION Conventional methods for manufacturing liquid crystal display devices include a printing method using a letterpress printing method and a coating method using a spinner or gun spray to form an alignment film. In addition, a spacer interposed between electrode-attached substrates in a liquid crystal display device is made of glass, plastic, or the like, and has a cylindrical or spherical shape. At this time, the composition of the glass should preferably contain very few alkaline elements (for example, 5in2 as the main component and A
It contains 1203, Fe20s, Na2O, K20, etc., and contains about 0.7 ppm of Na and K. In addition, hardened spherical fine particles containing a benzoguanamine formaldehyde condensate (existing chemical substance structure classification reference number 7-31) were used as a plastic spacer. There are generally two methods for dispersing spacers: an in-air method and an in-liquid method.

The air method is a method in which spacers are dispersed together with the airflow within the device, and the discharge airflow is approximately 0.3 kg/cj and 15 liters/min and allowed to fall freely, or conversely, the discharge airflow is approximately 4 kg/cj. /cj, 200 liters/m
There are some that are strong enough to make you fall.

The former can be dispersed relatively uniformly, but requires a long time to fall. Also, the latter can relatively shorten the falling time, but
This requires some ingenuity, and may result in a lump of spacer being ejected. The measures mentioned here include, for example, removing static electricity from the substrate and neutralizing it electrostatically, using the atomizing principle for supplying spacers to increase the flow rate and preventing spacers from clumping, and passing the spacers through a filter to remove any clumping beforehand. etc. Furthermore, whether the spacer is cylindrical or spherical, the fine powder used for the spacer is easily affected by static electricity, so in the air method, special measures against static electricity are required.

As the submerged method, a method of dispersing using a spinner or the like is generally known. If alcohol or acetone is used as a liquid to mix spacers, it will attack the surface of the alignment film and deteriorate the alignment properties. Therefore, using a chemically stable Freon liquid,
The solution mixed with the spacers is dropped onto the alignment film on the electrode-attached substrate set in a spinner, and the spinner is operated at about 100 r, p, m for about 3 minutes to disperse the spacers. Further, instead of dropping the liquid, it is possible to achieve even more uniform dispersion by dropping the liquid (mixed with spacers) evenly on the surface of the alignment film and then operating a spinner.

Organic materials such as polyimide and polyvinyl alcohol are used for the alignment film. For example, when printing using letterpress printing,
The ratio of the weight of polyimide to the weight of the solvent is about 7.5%wt, and in the case of spinner coating, it is about 3%wt. After applying the alignment film, a heating furnace was used to cure it, and it was heated in N2 for 1
Heat in the range of about 70°C to about 350°C for several hours.

FIG. 5 shows a state in which spacers are dispersed after forming an alignment film in this manner. A substrate with an electrode with a color filter and a substrate with an electrode with a TPT element (thin film switching element) are used in liquid crystal display devices such as color LCD televisions.
The figure shows a state in which spacers 16 are dispersed by an air method after an alignment film is formed on the electrode-attached substrate with the TPT element. The spacers 16 are evenly and almost uniformly distributed in the TFT element section 17, wiring section 18, and pixel section 19. Almost the same results are obtained whether the dispersion method is an in-air method or a sub-liquid method.

As a conventional technique, for example, Japanese Patent Application Laid-Open No. 59-222817
As shown in the publication, it had a structure as shown in Figure 6. A spacer material mixed with a photosensitive resin is applied onto a substrate, and spacers are formed at predetermined locations by a photomask process. Also, the spacer positions are changed to spacers 21, 22 located within the hatched area on the gate line 20 on the substrate, spacers 24, 25, 26 located on the source line 23, or spacers 24, 25, 26 located within the shaded area on the drain electrode 27. Installed at position 28, 29, 30 etc.
Avoid overlapping the thin film transistor part or the cross-over part with multilayer wiring. The structure is such that a spacer material such as a glass fiber is mixed into a photosensitive resin and applied to the entire surface by printing or other methods, patterned by a photomask process, developed, and then baked and hardened. In this way, in the conventional manufacturing method of liquid crystal display devices, glass fibers are mixed in and formed on the gate line and drain electrodes, which are wider than the line width (and may also be formed in the pixel area, resulting in poor image quality). In addition, the alignment treatment was insufficient in areas that protruded outside the line.Furthermore, the photosensitive resin used here was "Photonice UR-3100J" manufactured by Toshisha Co., Ltd., and the viscosity was Spacers exist in the photosensitive resin, and pressing is required to remove the photosensitive resin existing between the substrates in order to form a predetermined gap in the liquid crystal display device. etc. Moreover, since the adhesive is thick, it seems that the accuracy of the gap cannot be expected due to its viscosity.

Problems to be Solved by the Invention As described above, in the spacer manufacturing method used in the conventional manufacturing method of a liquid crystal display device, it is difficult to selectively form spacers, and even if spacers can be selectively formed, it is difficult to perform sufficient alignment treatment. In addition, since there is a spacer in the pixel portion, there is a problem in light extraction from the light source, which significantly deteriorates the image quality.

The present invention has been made in view of these points, and has an object to selectively form spacers with a simple configuration, provide sufficient alignment processing, eliminate the presence of spacers in pixel areas, and prevent light leakage from the light source. The purpose was

Means for Solving the Problems In order to solve the above problems, the present invention includes a set of substrates with electrodes, an alignment film formed on the substrate with electrodes, and a spacer fixed on the alignment film. , a small amount (both are fixed on the alignment film formed on one of the electrode-attached substrates by an adhesive having a photosensitive resin that exists between the spacer and the alignment film and is sufficiently thin compared to the size of the spacer. This is to obtain a liquid crystal display device in which spacers are arranged in an island shape, and is composed of a set of substrates with electrodes, an alignment film formed on the substrate with electrodes, and a spacer fixed on the alignment film. When manufacturing a liquid crystal display device, there are two steps: a step of mixing spacers and an adhesive, a step of applying the spacers and adhesive onto the alignment film on the substrate with electrodes, and a region where the spacers and the adhesive are mixed. This process consists of a step of forming the wafer into an island shape.

Function: The liquid crystal display device of the present invention has a photosensitive material that is present on the alignment film formed on one of the substrates with electrodes, between the spacer and the alignment film, and is sufficiently thin compared to the size of the spacer. Since the spacers fixed with an adhesive containing resin are arranged in an island shape, by fixing the spacers to the surface of the alignment film other than the pixel area on the substrate with electrodes, light leakage etc. can be eliminated and the surface of the alignment film can be fixed. Since there is no dripping or the like at the boundary between the liquid crystal display and the spacer, good alignment of the liquid crystal can be obtained, and a predetermined gap inside the liquid crystal display device can be precisely formed.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. A liquid crystal display device manufactured based on the manufacturing method of the present invention is shown in FIGS. 3 and 4.

In FIG. 3, the liquid crystal display device includes a front glass plate 7 having a transparent electrode 5 and an alignment film 6 thereon, a TFT element (a transistor element composed of a thin film transistor and used for switching the voltage applied to the pixel electrode) part 8, and Between the pixel part 9 and the liquid crystal display substrate 11 on which the alignment film 10 is attached, there is a sealing material 12 mixed with a predetermined spacer in the peripheral part, and the inside of the panel surrounded by the sealing material 12 is A liquid crystal 13 is present on the screen. Polarizing plates 14 and 15 are attached to both sides of the front glass plate 7 and the liquid crystal display substrate 11.

FIG. 4 shows the structure of 11 examples of substrates, where G is TPT.
The gate electrode of the device, ▪ is an insulating film, A is a channel active region made of amorphous silicon, and M is a source and drain electrode.

First, a method for manufacturing a liquid crystal display device according to the present invention will be explained. A printing method was used to form an alignment film made of polyimide on a substrate with electrodes. Screen printing and letterpress printing are generally used as printing methods, and letterpress printing was used in the present invention. Using a diluting solution consisting of NMP (N-methyl 2-pyrrolidinone) and butylcellolove, the polyimide stock solution was diluted to an approximately 8% solution, a predetermined pattern was printed by letterpress printing, and the mixture was heated in a clean oven.
It was cured at 70°C for 2 hours. Furthermore, it has been confirmed that the material cures similarly under conditions of 350° C. for 1 hour. A spacer that forms a gap between the liquid crystal panels on this alignment film,
Apply a solution containing a photosensitive resin. In this case, the photosensitive resin may be either a positive-type photoresist or a negative-type photoresist (in particular, a negative-type photoresist polyimide, which is the same material as the alignment film, was used for the intervening surface.

Further, the viscosity was adjusted to about 10 cps, and a spacer was added in a glass container, followed by thorough stirring. Although the spacer may be spherical or cylindrical, a spherical spacer made of plastic was used in this embodiment. The spacer is provided to regulate the gap between the substrates with transparent electrodes, and has a diameter of approximately 6μ.
The size is m. Methods for applying a solution containing a mixture of spacers and a photosensitive resin onto an alignment film previously formed on a substrate with transparent electrodes include printing using a spinner, spray, roll coater, screen printing, offset printing, and the like. In this example, the coating was particularly performed using a spinner.

The conditions for the spinner are as follows: A solution containing a sufficient mixture of spacers and photosensitive resin is evenly dropped onto the alignment film formed on the substrate with transparent electrodes, and after 30 seconds at 1100 rpm, the solution is heated at 3000 rpm.
pm for 10 minutes. The mixing ratio of the spacer and the above solution is approximately 1:100. In this state, photolithography exposure using ultraviolet rays and further etching were performed to form a predetermined pattern. FIG. 2 shows a state in which a predetermined pattern has been formed. When doing this, the predetermined pattern 3 was formed on the wiring section 4 on the liquid crystal display substrate, and was made smaller than the width thereof. On the opposite side of the liquid crystal display device, there is a color filter in which a light shielding part is formed, and the width of the predetermined pattern is sufficiently smaller than the width of the light shielding part formed in the color filter.

In addition, a solution containing a sufficient mixture of spacers and photosensitive resin was evenly dropped onto the alignment film of the color filter located on the opposite side of the liquid crystal display substrate, and the coating was applied at 1100 rpm for 30 seconds and then at 3000 rpm for 10 minutes. Similarly, a predetermined pattern can be formed by performing photolithography exposure and etching. Furthermore, in this example, after forming a predetermined pattern on a liquid crystal display substrate, alignment treatment was performed, and it was confirmed that the image quality of the liquid crystal display device was good. A liquid crystal display device is completed by bonding a liquid crystal display substrate and a color filter on the opposite side with an intervening adhesive, and then injecting and sealing liquid crystal.

FIG. 1 shows a state in which spacers coated on an alignment film on a liquid crystal display substrate are cured with a photosensitive resin.

While the size of the spacer 1 formed on the alignment film is 6 μm, the size of the adhesive 2 made of photosensitive resin is at most 20 μm.
0.008, which is sufficiently thin, so that the gap between the substrates in a liquid crystal display device is approximately equal to the size of the spacer. Furthermore, the pattern consisting of the spacer is formed on the wiring part within the screen, is island-shaped, and is smaller than the width of the wiring part, and as mentioned earlier, the wiring part within the screen is shielded from light by the light-shielding part of the color filter. has been
Since the pattern made of spacers is not visible within the screen, the image quality is good. The wiring portion is made of Ae or the like, and has a thickness of about 7000A. The value of the compressive strength of Ae is much larger in a thin film form than in a bulk form. The concrete compressive strength of At is approximately 0.25 kg/c in bulk form.
d or more, and in the case of a thin film, about 1 k+r / cd
That's all. Therefore, even if an island-shaped spacer is formed on the wiring board, the wiring portion will not be destroyed by the pressure as long as the pressure is less than about 1kIr/cr1 in the manufacturing process of a liquid crystal display device. Furthermore, when only a cylindrical spacer made of a glass component was dispersed, it was confirmed by visual inspection that the transistor part was destroyed and a point defect was caused, and it was also confirmed that the cylindrical spacer itself was destroyed. Furthermore, when only plastic spherical spacers are dispersed,
It was confirmed that the spherical spacer was compressed and deformed under pressure. However, it was not possible to visually inspect the wiring for damage or spacer impressions. Furthermore, when an island-shaped spacer is formed on a wiring part, it is not possible to visually inspect the wiring part for destruction as in the case of a cylindrical spacer made of glass and a spherical spacer made of plastic.

In addition, there are methods for applying a solution containing a spacer and a photosensitive resin onto a substrate with electrodes, in addition to the above-mentioned method using a spinner, methods such as spraying, using a roll coater, etc.
There are methods using screen printing, etc., and both can form a thin film similar to that using a spinner, and can also fix the spacer on the substrate.

Further, photolithography exposure and etching are used to form the thin film formed by the above method into a predetermined shape and a precise pattern.

After forming spacers on the alignment film, alignment treatment is performed. The oblique vapor deposition method and the rubbing method are well known as orientation processing methods. The rubbing method is a method of rubbing the surface of an alignment film formed on a substrate with a cloth such as nylon or rayon, and is a process performed to give directionality to liquid crystal molecules in a liquid crystal display device. When the surface of the alignment film formed on the substrate was visually inspected after rubbing, it was found that about 1% of the spacers had fallen off. However, this amount of reduction had little effect on forming the gap in the liquid crystal display. When using the rubbing method, it is appropriate to perform it after forming spacers on the surface of the alignment film. However, when using the oblique vapor deposition method, it may be performed either before or after forming the spacer on the surface of the alignment film.

In this example, a liquid crystal display device was manufactured using a rubbing method, and the image quality was evaluated.

If a spacer exists within a pixel, the spacer prevents the liquid crystal from existing, and in a state where it blocks light from a light source, light leaks out as an image, resulting in a defect in which stars appear to be in the night sky. Further, since the film thickness of the photosensitive resin mixed in the spacer was thin, no sagging was caused by coating around the spacer.

As described above, according to this embodiment, since there are no spacers in the pixels within the screen of the liquid crystal display device, there is no light leakage, and the image quality is good.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) By fixing the spacer to the surface of the alignment film other than the pixel portion on the substrate with electrodes, light leakage etc. is eliminated.

(2) Since there is no dripping or the like at the boundary between the alignment film surface and the spacer, good liquid crystal alignment can be obtained.

(3) A predetermined gap inside the liquid crystal display device can be formed with high precision.

(4) You can change to a liquid crystal display device with superior display quality.

(5) A large amount of processing can be performed relatively stably.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a spacer of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a plan view of a substrate showing the position of the spacer, and FIG. 3 is a sectional view of a liquid crystal display device of the present invention. Figure 4 is a cross-sectional view of the TPT element part and pixel part of the same liquid crystal display device.
FIG. 5 is a plan view of a substrate showing the position of spacers in a conventional example;
FIG. 6 is a plan view of a conventional substrate with the positions of spacers enlarged. DESCRIPTION OF SYMBOLS 1... Spacer, 2... Adhesive, 3... Pattern, 4... Wiring part, 5... Transparent electrode, 6... Alignment film, 7... Front glass, 8...・TPT element part, 9...
- Pixel portion, 10... Alignment film, 11... Liquid crystal display substrate, 12... Sealing agent, 13... Liquid crystal, 14.15
...Polarizing plate, 16...Spacer, 17...TPT
Element section, 18... Wiring section, 19... Pixel section, 20.
...Gate line, 21.22...Spacer, 23.
...Source line, 24,25.26...Spacer,
27...Drain electrode, 28.29.30...Spacer. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 m2

Claims (8)

[Claims] (1) A set of substrates with electrodes, an alignment film formed on the substrate with electrodes, and a spacer fixed on the alignment film, wherein the substrates with electrodes are formed on at least one of the substrates with electrodes. The spacer is arranged in an island shape on the alignment film, and is fixed by an adhesive having a photosensitive resin that is sufficiently thin compared to the size of the spacer and is present at the interface between the spacer and the alignment film. LCD display device. (2) The spacer exists outside the pixel part of the substrate with electrodes,
2. The liquid crystal display device according to claim 1, wherein the width of the spacer is sufficiently smaller than the width of the light-shielding portion of the pair of electrode-equipped substrates. (3) When manufacturing a liquid crystal display device composed of a set of electrode-equipped substrates, an alignment film formed on the electrode-equipped substrate, and a spacer fixed on the alignment film, the spacer and the adhesive are bonded together. a step of applying the spacer and the adhesive onto the alignment film on the electrode-equipped substrate; and a step of forming an island-like region in which the spacer and the adhesive are mixed. A method for manufacturing a liquid crystal display device, comprising: (4) The step of applying the spacer and the adhesive onto the alignment film on the electrode-equipped substrate includes applying the spacer and the adhesive onto the orientation film on the electrode-equipped substrate using a spinner. 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein the method is a step. (5) The step of applying the spacer and the adhesive onto the alignment film on the substrate with electrodes includes applying the spacers and the adhesive onto the alignment film on the substrate with electrodes by spraying. 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein the method is a step. (6) The step of applying the spacers and the adhesive onto the alignment film on the electrode-equipped substrate includes applying the spacers and the adhesive onto the electrode-equipped substrate using a printing method using a roll coater. The method for manufacturing a liquid crystal display device according to claim 3, characterized in that the step is a step of coating. (7) The step of applying the spacer and the adhesive onto the alignment film on the electrode-equipped substrate includes applying the spacer and the adhesive onto the electrode-equipped substrate using a screen printing method. 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein the method is a coating step. (8) The step of forming an island-like region in which the spacer and the adhesive are mixed forms the spacer and the adhesive into a predetermined shape on the alignment film on the electrode-equipped substrate by photolithography exposure and etching. 4. The method for manufacturing a liquid crystal display device according to claim 3, wherein the step is to form a liquid crystal display device.