JPH01134336A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display device in which spacers do not exist in picture element parts and do not deteriorate the degree of orientation by disposing and fixing the spacers to island shapes on the oriented film formed on at least one substrate with electrodes. CONSTITUTION:The oriented film 1 consisting of UV curing type or thermosetting type polyamide is formed on at least one substrate of one set of the substrates 2 with the electrodes. Photosensitive polyimide 3 consisting of the UV curing type polyamide or a mixture composed of a pigment and the UV curing type polyimide is applied on this oriented film 1 to a prescribed film thickness. Only the prescribed part is exposed by photolithography and is then worked to the spacers 5 of the prescribed shape. The spacers 5 are thereby fixed to the surface of the oriented film 1 except the picture element parts on the substrate 2 with the electrodes, by which the light leakage, etc., in the picture elements are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 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 that determines the alignment of liquid crystal molecules. and its manufacturing method.

BACKGROUND OF THE INVENTION Conventional methods for manufacturing liquid crystal display devices include printing methods such as letterpress printing and coating methods using a spinner or gun spray to form an alignment film. Further, spacers interposed between electrode-attached substrates in a liquid crystal display device are made of glass, organic resin, or the like, and have a cylindrical or spherical shape. At this time, it is desirable to minimize the amount of alkaline elements in the glass composition from the viewpoint of reliability with the liquid crystal. For example, with S10□ as the main component and M
05+Fe 203. Na2O, contains 20 etc.
A material containing about 0.7 ppm of Na and K is used. In addition, benzoguanamine formaldehyde condensate (existing chemical substance structure classification reference number 7-31) is added to organic resin.
) was used. There are two methods for dispersing spacers: an in-air method and an in-liquid method. The air method is a method in which the spacer is dispersed with the airflow within the device, and the discharge airflow is about 0.3Ks+/i or 1ts d/win and is allowed to fall freely, or conversely, the discharge airflow is set to 4Kg/crl.
There are some that are forced to fall at a rate of about 200 l/win. The former can be dispersed relatively uniformly, but requires a long time to fall. Although the latter method can relatively shorten the falling time, it requires some ingenuity and may result in a lump of spacer being ejected.

The ideas mentioned here include, for example, removing static electricity from the substrate and neutralizing it electrostatically, using a spray principle to increase the flow rate and preventing spacers from clumping, and passing the spacers through a filter to remove any clumping beforehand. etc. The fine powder used for spacers, whether cylindrical or spherical, is susceptible to static electricity, so static electricity countermeasures are especially necessary in the air method.

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 fluorocarbon solution, the solution containing the spacer was formed into droplets on the alignment film on the electrode-equipped substrate set on a spinner, and 100 r, p, m,
After about 60 seconds, 200 Or, p, m, about 3
Operate for about a minute to disperse the spacers. Further, instead of dropping the solution mixed with spacers, the solution mixed with spacers can be evenly dropped on the surface of the alignment film and then the spinner can be operated to achieve more uniform dispersion.

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 solvent is approximately 7.54 W.
When applying with a spinner, it is approximately 4.51
Wt, and when applied with a spray gun, approximately 3%wt
It is. After the alignment film is applied, it is cured by heating in a N2 atmosphere at a temperature ranging from about 170'C to about 350C for several hours using a heating furnace.

FIG. 7 shows a state in which spacers are dispersed after forming an alignment film in this manner. A liquid crystal display device such as a color liquid crystal television uses a substrate with an electrode with a color filter and a substrate with an electrode with a TPT element (thin film switching element). The figure shows a state in which the spacers 24 are dispersed by an air method after forming.

The spacer 24 is connected to the TFT element section 26. The wiring portion 26° and the pixel portion 27 are evenly and almost uniformly distributed. Almost the same results are obtained whether the dispersion method is an air method or a liquid method.

Furthermore, it is difficult to perform selective dispersion without the presence of spacers in the pixel portion using these methods.

Problems that the invention sought to solve As described above, in the conventional manufacturing method of a liquid crystal display device, a cylindrical or spherical spacer is used to form a gap between a pair of electrode-attached substrates in a liquid crystal display device. However, although it was possible to disperse the particles evenly and almost uniformly on the electrode-attached substrate, it was difficult to selectively disperse the particles so that no spacers were present in the pixel portions.

Therefore, due to the spacer present in the pixel portion, the liquid crystal is not present in that portion, causing light leakage, resulting in a decrease in contrast and the like, resulting in deterioration of image quality.

The present invention has been made in view of the above points, and includes a liquid crystal display device having a simple configuration, a spacer not being present in the pixel portion, fixed on the alignment film, and not deteriorating the degree of alignment, and manufacturing thereof. The purpose was to provide a method.

Means for Solving the Problems In order to solve the above problems, the present invention is composed of a set of electrode-equipped substrates, an alignment film formed on the electrode-equipped substrates, and a spacer, and the spacers include at least The liquid crystal display device is characterized in that the spacers are fixed on the alignment film formed on one of the electrode-equipped substrates and are arranged in an island shape.

The present invention also provides a step of applying the alignment film onto the substrate when manufacturing a liquid crystal display device comprising a set of electrode-equipped substrates, an alignment film formed on the electrode-equipped substrate, and a spacer. a step of curing the alignment film; a step of applying a material for forming the spacer; a step of exposing the spacer to a predetermined shape by photolithography; and a step of processing the spacer into a predetermined shape by etching. A method of manufacturing a liquid crystal display device is characterized in that it comprises the steps of:

Function The liquid crystal display device of the present invention has a structure in which a spacer is formed on the alignment film other than the pixel area after forming the alignment film, and has the effect of preventing light leakage due to the spacer in the pixel area and improving image quality. It is. In addition, in the method for manufacturing a liquid crystal display device of the present invention, the surface of the alignment film is hardened in advance when forming the spacer after forming the alignment film, so that the alignment characteristics of the surface of the alignment film are not deteriorated, and the pixel Since the spacer is selectively formed in areas other than the pixel area, it has the effect of preventing light leakage due to the spacer in the pixel area and improving image quality.

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.

In FIG. 5, the liquid crystal display device includes a front glass plate 16 having a transparent electrode 13 and an alignment film 14 thereon, a TPT element (a transistor element composed of a thin film transistor and used for switching the voltage applied to the pixel electrode) part 16, and Between the pixel part 17 and the liquid crystal display substrate 19 on which the alignment film 18 is attached, there is a sealant 20 mixed with a predetermined spacer in the peripheral part, and the inside of the panel surrounded by the sealant 20 is A liquid crystal 21 is present on the screen. And polarizing plate 22゜2
3 is attached to both sides of the front glass plate 16 and the liquid crystal display substrate 19.

FIG. 6 shows the structure on the substrate 19 side, where G is TPT.
The gate electrode of the device, I is an insulating film, M is a channel active region made of amorphous silicon, and M is a source and drain electrode.

FIG. 1 is a cross-sectional view of the vicinity of an alignment film manufactured by the method for manufacturing a liquid crystal display device of the present invention. Each step is shown from a to d. FIG. 1a is a cross-sectional view of the substrate in the step of forming an alignment film on the electrode-attached substrate.

Methods for forming the alignment film 1 on the electrode-attached substrate 2 include a letterpress printing method, a spinner coating method, a gun spray method, and the like. In the present invention, photosensitive polyimide was applied using a spinner coating method. The spinner conditions are approximately 10 Or, p, m, ,
After about 30 seconds, about 400 Or, p, m, and about 180 seconds were carried out. The photosensitive polyimide could be coated into a substantially uniform film with a thickness of about 200m. After quickly drying the film surface at about 90° C. for 10 seconds, only a predetermined pattern was exposed. The exposure light source is Ha-
(, d laser was used.Although an alignment film is applied to the wiring part and the counter electrode extraction part, if it is not exposed to light, the photosensitive polyimide is a negative type and can be removed.Also, an alignment film with a smooth surface can be obtained, and it can be removed by etching. After cleaning, a predetermined pattern could be formed.The polyimide portion was further hardened by placing it in a heating furnace.

Next, FIG. 1 shows a sectional view of a substrate with electrodes in which a photosensitive polyimide is further coated on the formed alignment film. Apply photosensitive polyimide 3 using a spinner.

In order to obtain a film thickness of about 3 μm, we tried a method of applying the film several times and a method of applying it once. When applying once, it was difficult to control the viscosity, but the undiluted solution had a relatively slow rate of approx.
p, m,, about 50 Or, p, m,, about 12 after about 30 seconds
The film thickness could be achieved under conditions of 0 seconds.

FIG. 1C is a sectional view of the electrode-attached substrate showing how only a predetermined spacer portion is exposed. The exposed portion 4 is a spacer of a predetermined shape. A He-Cd laser was used as a light source. Exposure time is about 30 seconds.

FIG. 1d is a cross-sectional view of the electrode-attached substrate showing the spacer heated and hardened after the etching process.

When etching is performed, the portions exposed in the previous step are formed as spacers 6. Further heating and curing forms spacers as shown in the figure.

As described above, the spacers are formed at predetermined positions facing each other on a pair of electrode-equipped substrates. FIG. 2 is a cross-sectional view of a pair of electrode-attached substrates showing how opposing spacers are in contact with each other. The spacer 6 can be easily aligned in a predetermined position by aligning a pair of electrode-attached substrates.

FIG. 3a is a plan view of an electrode substrate with a TPT element portion, and FIG. 3 is a sectional view of the same substrate. When a spacer is formed on the TPT element portion T, the spacer 8 can cover the semiconductor portion 9 as shown in b.

When a spacer is formed by pre-mixing a pigment in this photosensitive polyimide, it becomes a light-shielding film and improves TPT characteristics.

In this case, it is desirable that the spacer be formed on each TPT element portion. A considerable number of spacers are required to achieve a spacer suppression of approximately 0.6 Kg/6i. The presence of a spacer in each element portion prevents the element portion from being damaged.

FIG. 4a is a plan view of an electrode substrate with a TPT element portion, and FIG. 4 is a sectional view of the same substrate. Wiring section 1 other than TPT element section
In the case where the spacer 11 is formed in the area o, the spacer 11 can be formed in the state shown in FIG. A predetermined number of spacers 11 can be freely formed, and a predetermined number of spacers corresponding to a predetermined pressing force of the spacers can be formed. Wiring section 10
When the spacer 11 is formed in the TPT element portion 12, it is possible to prevent the source and the drain from being short-circuited or damaged due to damage to the TPT element portion 12.

Therefore, as described above, spacers can be formed on areas other than the pixel areas on the alignment film, and since the surface of the alignment film is not damaged, there is no problem with the alignment of liquid crystal molecules and the effect of improving image quality is achieved. have

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 liquid crystal display device with excellent display quality can be obtained.

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

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a substrate in a process based on a method for manufacturing a liquid crystal display device that is an embodiment of the present invention, FIG. 2 is a cross-sectional view of a liquid crystal display device that is an embodiment of the present invention, and FIG. &,
4b is a plan view and an x-x' sectional view of a liquid crystal display device which is an embodiment of the present invention, respectively, and FIGS. 4a and 4b are a plan view and Y -Y'
6 is a sectional view of a liquid crystal display device manufactured using the method of manufacturing a liquid crystal display device of the present invention, FIG. 6 is a sectional view of a TPT element portion and a pixel portion of the same device, and FIG. 7 is a sectional view of a conventional liquid crystal display device. FIG. 2 is a plan view of a liquid crystal display device in an example. 1...Alignment film, 2...Substrate with electrode, 3
...Photosensitive polyimide, 4...Exposed portion, 5...Spacer, 6...Spacer, 7. Mountain...TFT element part, 8 ...Spacer, 9...Semiconductor part, 1o...Wiring part, 11...Spacer, 12...TF
T element part, 13...Transparent electrode, 14...
・Alignment film, 16...Front glass plate, 16...
...TFT element section, 17... Pixel section, 18.
...Alignment film, 19...Liquid crystal display substrate,
20... Seal agent, 21... River/liquid crystal, 22.
23...Polarizing plate, 24...Spacer,
25...Mark TFT element part, 26...Wiring part,
27...TFT element section. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure Cα) (b) (d) Figure 2 Figure 3 (0L) (b) 94 conductor first Figure 4 (α)

Claims (4)

[Claims] (1) Consisting of a pair of electrode-equipped substrates, an alignment film formed on the electrode-equipped substrate, and a spacer, wherein the spacer is arranged on the alignment film formed on at least one of the electrode-equipped substrates. A liquid crystal display device, wherein the spacers are fixed and arranged in an island shape. (2) The liquid crystal display device according to claim 1, wherein the alignment film is made of ultraviolet curing or thermosetting polyimide. (3) Is the spacer made of ultraviolet curing polyimide?
Alternatively, the liquid crystal display device according to claim 1 is made of a mixed material of a pigment and an ultraviolet curable polyimide. (4) 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, a step of applying the alignment film on the substrate; , a step of curing the alignment film, a step of applying a material for forming the spacer, a step of exposing the spacer to a predetermined shape by photolithography, and a step of processing the spacer into a predetermined shape by etching. A method for manufacturing a liquid crystal display device, comprising: