JPH1010543A - Liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the deterioration in image quality by the low luminance defect of a display section by arranging sealing materials and spacers between substrates and changing the spraying density on the substrates. SOLUTION: Oriented films 105, 106 adhered to both substrates of the counter substrate 101 and the TFT substrate 102 are baked. A rubbing stage of forming fine grooves by rubbing the glass substrate surfaces adhered with the oriented films 105, 106 with buffing cloth (fibers of rayon, nylon, etc.) of, for example, 2 to 3mm in hair length to a specified direction is thereafter executed. The spherical spacers 107, such as polymer system and silica system, are then sprayed on the TFT substrate 102 or counter substrate 101. At this time, the spraying density of the specers 107 is changed according to purposes. As a result, the unequalness of the cell gap of the liquid crystal display device is corrected and the spacer spraying amt. of the pixel parts is decreased. The occurrence of the low luminance defect of the display section by spraying of the spacers is lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention aims at improving the display state of a liquid crystal display device. In particular, it is to reduce the cell gap unevenness of the panel. The present invention also aims at improving the display state by reducing the amount of spacers scattered in the pixel portion.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have shown remarkable development,
Due to its low power consumption and portability, it is widely used in various devices. However, with the practical use of liquid crystal display devices, various improvements are required.

In particular, there is a demand for an improved display state as a display device. For example, the display area is enlarged. A display area as large as possible is required even with the same panel size. There is also a strong demand for improving the quality of the display state of the liquid crystal panel.

Among them, in an active matrix type liquid crystal display device including a thin film transistor (TFT) using crystalline silicon, a peripheral driving circuit and a pixel driving circuit can be formed on the same substrate.

[0005] For this reason, this device has a very large display area of pixels with respect to the size of the display device. Further, since the pixel pitch can be reduced, a high-definition image can be provided. Further, in the active matrix type liquid crystal display device, a display material is further enlarged by forming a sealant on a peripheral driving circuit.

However, in a conventional liquid crystal display device, a filler having high hardness is mixed in a sealing material. The filler is a substance formed of glass fiber or the like for controlling the distance between substrates, and has a rod-like or spherical shape.

In this case, if a sealing material is used on the driving circuit in the liquid crystal display device with a built-in driving circuit, the driving circuit element is destroyed by the pressure applied during cell formation. For this reason, the display state of the panel has been impaired, and the yield has been reduced. In order to prevent this, a method has been adopted in which a filler for maintaining a space between substrates is not mixed into a sealing material on a driving circuit.

By the way, in a liquid crystal display device, uneven substrate spacing directly leads to display color unevenness or the like. For this reason, the liquid crystal display device generally uses a spacer to make the distance between the substrates uniform.

It is known that the cell gap of a liquid crystal display device depends on the density of spacers. For this reason, the spacers are distributed in the cells at a uniform density. Changes in the spacer diameter also affect the cell gap. For this reason, the spray spacer diameter in the panel is usually uniform.

The spacer is a spherical spacer mainly made of silica, resin or the like, and is used for controlling the distance between the substrates by dispersing the spacer between the substrates. In particular, since the spacer formed of resin or the like has a certain degree of elasticity, there is little risk that the TFT or the like on the substrate is damaged by the spacer.

[0011]

2. Description of the Related Art As described above, in a liquid crystal display device, a spacer has an effect of maintaining a distance between substrates. However, there has been reported an example in which the spacers are sprayed on the pixel portions to impair the display state of the panel. For example, when a light-transmitting spacer is used, light leakage occurs in a dark state of the panel. This is called a low luminance defect.

Particularly, a liquid crystal panel used as a projection type has an enlarged display portion. Thereby, the low-luminance defect of the spacer is enlarged and displayed. This has led to a decrease in the contrast of the display unit and a deterioration in the display quality.

However, in practice, in order to maintain the distance between the substrates, it is unavoidable to spray some spacer. Therefore, in order to reduce the amount of spacers to be scattered in the pixel region, it is conceivable to increase only the amount of scattered spacers in regions other than the pixel region.

However, as described above, the spacer distribution density affects the cell gap. Therefore, if the spacer distribution density of the pixel portion and the spacer distribution density of the region other than the pixel portion are changed, the cell gap changes around the pixel portion. Since such a change in the cell gap causes disorder of the display state, the above-described method cannot improve the display state of the liquid crystal display device.

[0015] Further, as described above, in the case where the filler for maintaining the substrate interval is not included in the sealing material on the drive circuit, it is significant in that damage to the drive circuit element is prevented. It has been found that the display state of the liquid crystal panel has the following serious drawbacks.

In a liquid crystal display device, two glass substrates are bonded after the application of a sealing material. For example, the sealing material is cured while uniformly applying pressure to the inside of the substrate. The curing method of the sealing material includes curing by UV irradiation, curing by heat, and curing using both UV irradiation and thermal curing.

During the thermal curing of the sealing material, heat of about 160 ° C. is applied. Also, when UV irradiation and thermal curing are used in combination, heat of about 90 ° C. is required. After the sealing material is cured, the liquid crystal panel is returned to room temperature.

In a liquid crystal panel in which a filler for maintaining a distance between substrates is not mixed in a sealing material, the cell gap becomes non-uniform due to the temperature change. FIGS. 3 and 5 show the results of actual measurement.

FIG. 3 shows the distribution density of the spacer in the substrate as 50.
This is a result of examining the cell gap distribution in the substrate when the cell gap was changed to about 300 cells / mm ² . The horizontal axis indicates the distance from the center of the substrate, and the vertical axis indicates the cell gap. Also,
FIG. 5 is a three-dimensional view showing the cell gap distribution in the substrate when the spacers are uniformly sprayed at 50 pieces / mm ² .

In this experiment, a cell was manufactured without using a filler for maintaining the distance between the substrates in the sealing material. The cell is formed through the steps of dispersing spacers, applying a sealing material, and thermally curing the sealing material (substrate bonding). The size of the substrate used here is 5.0 inches in width (the distance from the center of the substrate is 2.5 inches in FIG. 3) and 5.0 inches in height. No liquid crystal injection was performed. The spacer is made of resin. The spacer diameter is 4.0 μm.

In FIG. 3, it can be seen that the cell gap differs between the cell center and the cell outer part, and the cell gap is thicker in the cell center than in the cell outer part. Further, the difference is as large as 1.0 to 1.2 μm. This means that the cell gap is the largest at the center of the substrate (corresponding to the address 3-3) in FIG.
It is also evident from the fact that it is the smallest.

As a driving method of a liquid crystal display device used in recent years, a TN method, an STN method, and the like are generally used.
Here, the cell gap control accuracy required to obtain good display uniformity is ± 0.1 μm in the TN method.
m, ± 0.03 μm in the STN system.

Therefore, the cell gap unevenness observed in FIG. 5 indicates that the liquid crystal display device is not practical. This can be presumed to be due to the fact that the sealing material does not use a filler for maintaining the distance between the substrates, so that the sealing material undergoes thermal contraction, and slight warpage of the substrate changes the cell gap.

[0024]

The invention disclosed in this specification aims at improving the display state of a liquid crystal display device. Specifically, it is to reduce the cell gap unevenness of the liquid crystal panel. Another object of the present invention is to reduce deterioration of image quality due to a low-luminance defect of a display unit due to a spacer, which causes display deterioration particularly in a projection display.

[0025]

In order to solve the above problems, the present invention provides a pair of substrates at least one of which is transparent,
An electrode formed on at least one of the substrates, and a liquid crystal layer sandwiched between the substrates, a sealing material and a spacer are disposed between the substrates, and the density of the spacers on the substrate is reduced. A liquid crystal display device characterized by changing.

Further, in the region where the sealing material is arranged in the preceding stage, the distribution density of the spacer is constant, and the distribution density of the spacer gradually decreases inward from the region surrounded by the sealing material. A liquid crystal display device characterized by the following. Alternatively, the liquid crystal display device is characterized in that the scattering density of the spacer increases substantially concentrically from the center of the region surrounded by the sealing material.

Further, the present invention includes a pair of substrates, at least one of which is transparent, electrodes formed on at least one of the substrates, and a liquid crystal layer sandwiched between the substrates, wherein at least one of the substrates is provided. A drive circuit and a pixel region are formed, a sealant is present on the drive circuit of the substrate, a filler for keeping a substrate interval is not mixed in the sealant, and the substrate interval is arranged between the substrates. A liquid crystal display device, wherein the liquid crystal display device is secured by a spacer provided, and the distribution density of the spacer changes on the substrate.

Also, in the preceding stage, the distribution density of the spacers is constant in the region surrounded by the sealing material, and the distribution density of the spacers gradually decreases inward from the region surrounded by the sealing material. A liquid crystal display device characterized by the following. Alternatively, the liquid crystal display device is characterized in that the scattering density of the spacer increases substantially concentrically from the center of the region surrounded by the sealing material.

Further, the present invention includes a pair of substrates at least one of which is transparent, electrodes formed on at least one of the substrates, and a liquid crystal layer sandwiched between the substrates, wherein at least one of the substrates is provided. A pixel region is formed, a sealant and a spacer are arranged between the substrates, the spacer distribution density of the pixel region is uniform, and the distribution density of the spacer from the pixel region to a region outside the pixel region. Is gradually increased.

Further, in the liquid crystal display device in the preceding stage, particularly, the distribution density of the spacers in the region surrounded by the sealing material is equal.

According to the present invention, the cell gap is made uniform by changing the distribution density of the spacers in the pixel region in the liquid crystal display device. Specifically, by gradually increasing the spacer scattering density toward the outside of the panel, cell gap unevenness in the panel is prevented.

Further, in the present invention, by gradually increasing the distribution density of the spacers toward the outside of the pixel area, it is possible to prevent the cell gap unevenness near the pixel portion due to the increase of the spacer distribution amount. By adopting this method, it is possible to reduce the amount of spacers to be scattered in the pixel area without impairing the display state.

FIG. 1 shows an example of a configuration utilizing the invention disclosed in this specification. The substrate shown in FIG. 1 has a driving circuit built-in type in which a pixel TFT and a driving circuit TFT are formed on the same substrate. Spacer distribution density is pixel area (A)
From the pixel region toward the pixel region end (B). Further, a sealant is formed on the drive circuit. No filler for maintaining the distance between the substrates is mixed in the sealing material.

In the configuration shown in FIG.
Are the first and second substrates, 103 and 104 are transparent electrodes, 105 and 106 are alignment films, 107 is a spacer,
08 denotes a pixel TFT, 109 denotes a driving circuit TFT, 110 denotes a sealing material, 111 and 112 denote polarizing plates, and 113 denotes a pixel region. In the pixel region (113), the spacer scatter density gradually increases from A to B. The liquid crystal material is not shown in this drawing.

The configuration of the present invention will be described below. First, for the first and second substrates (101, 102), a material having a light-transmitting property and a certain strength against external force, for example, an inorganic material such as glass or quartz can be used. .

A non-alkali glass or quartz glass is used for a substrate on which a TFT or the like is formed (hereinafter, referred to as a TFT substrate). When the purpose is to reduce the weight of the liquid crystal electro-optical device, a film having low birefringence, for example, PES (polyethylene sulfate) can be used.

As the transparent electrodes (103, 104), I
A light-transmitting conductive material such as TO (indium tin oxide), tin oxide, and indium oxide is used.

As the alignment film (105, 106), polyimide or polyamic acid obtained by dissolving 5 to 10% by weight in a solvent is used.

As the spacer (107), a spacer of polymer type, silica type or the like is used at a predetermined spray density. In the pixel area (113), any area (A) in the pixel area
From the direction toward the pixel region end (B), the spacer scattering density gradually increases.

As the TFTs (108, 109), those using crystalline silicon for the active layer can be used.
As the configuration of the driving element, a known configuration such as a planar type, a stagger type, and an inverted stagger type can be used.

Since a transistor using crystalline silicon is used, a driving circuit TFT (1) constituting a peripheral driving circuit is used.
09) and the pixel TFT (108) constituting the pixel area can be formed on the same substrate.

The peripheral drive circuit can be manufactured by the same process as that for manufacturing the TFT constituting the active matrix circuit. Peripheral drive circuits are generally nc
It is formed from a complementary element combining an h-type TFT and a p-ch type TFT.

Metal materials such as copper, aluminum, tantalum, titanium, and chromium are used as materials for forming each electrode of the TFT in the pixel region and the drive circuit region, such as the drain electrode, the gate electrode, and the gate line. Also, I
A light-transmitting conductive material such as TO (indium tin oxide), tin oxide, or indium oxide may be used.

Further, silicon oxide or silicon nitride can be used for each interlayer insulator and TFT protective film. Here, when a transparent organic film is used, not only an effect as an interlayer film and a protective film but also an effect as a flattening film can be provided.

As the sealing material (110), a resin material such as a thermosetting type or an ultraviolet setting type is used. As the resin material, an epoxy-based material, a urethane acrylate-based material, a silicon-based material, or the like can be used. Further, no filler for controlling the distance between the substrates is mixed in the sealing material.

Further, by the polarizing plates (111, 112),
Light modulation by a liquid crystal material (not shown) can be made visible.

[0047]

According to the structure of the present invention, it is possible to correct the uneven cell gap of the liquid crystal display device. Further, the present invention can be applied to all panels having uneven cell gaps after the formation of the substrate.

It is particularly effective to apply the present invention to a liquid crystal display device with a built-in drive circuit. With the structure of the present invention, a uniform cell can be provided without using a filler in the sealing material. Of course, not including a filler having high hardness in the sealant is effective in preventing the drive circuit from being damaged.

Further, by adopting the structure of the present invention, it is possible to reduce the amount of scattered pixel portion spacers. This can reduce the occurrence of low-luminance defects in the display section due to the spacers. At this time, no cell gap unevenness occurs in the pixel portion.
This is particularly effective when the panel is used as a projection display.

[0050]

【Example】

[Embodiment 1] In this embodiment, an example of a process of assembling a liquid crystal panel by changing the density of the used spacers will be described. The description follows FIG. 1 and FIG. FIG. 1 shows an example in which a cell is formed using a TFT substrate and a counter substrate. FIG. 4 shows a driving circuit TFT and a pixel TF on the same substrate.
4 shows an example of a method for forming T.

A manufacturing process for obtaining the active matrix circuit of this embodiment will be described with reference to FIGS. The left side of the figure shows the manufacturing process of the TFT of the peripheral driving circuit, and the right side shows the manufacturing process of the TFT of the active matrix circuit.

First, a quartz substrate or a glass substrate (40
1) A thickness of 1000 to 3 as a base oxide film (402) on top
A silicon oxide film of 2,000 ° is formed. As a method for forming the silicon oxide film, a sputtering method in an oxygen atmosphere or a plasma CVD method may be used.

Next, an amorphous or polycrystalline silicon film is formed by plasma CVD or LPCVD.
0 to 1500 °, preferably 500 to 1000 °.

Then, at a temperature of 500 ° C. or more, preferably 80 ° C.
Thermal annealing is performed at a temperature of 0 to 950 ° C. to crystallize the silicon film. After crystallization by thermal annealing, optical annealing may be performed to further improve the crystallinity. In addition, during crystallization by thermal annealing,
As described in -244103 and 6-244104, an element (catalytic element) for promoting crystallization of silicon such as nickel may be added.

Next, the silicon film is etched, and the active layers (403) (for P-channel TFTs) and (404) (for N-channel TFTs) of the TFTs of the island-shaped peripheral drive circuit and the TFTs of the matrix circuit (for the N-channel TFTs) are formed. Pixel TFT) active layer (40
5) is formed.

Further, a gate insulating film (406) of silicon oxide having a thickness of 500 to 2000 Å is formed by a sputtering method in an oxygen atmosphere. As a method for forming the gate insulating film, a plasma CVD method may be used. Plasma CV
When the silicon oxide film is formed by the method D, the source gas is dinitrogen monoxide (N ₂ O) or oxygen (O ₂ ).
And monosilane (SiH ₄ ).

Then, a thickness of 2000 to 50,000 mm,
Preferably, 2000-6000 ° aluminum is formed on the entire surface of the substrate. Then, this is etched to form gate electrodes (407, 408, 409). (FIG. 4
(A))

Thereafter, phosphorus is implanted into all the island-shaped active layers in a self-aligned manner using phosphine (PH ₃ ) as a doping gas by using the gate electrode as a mask by an ion doping method. The dose is 1 × 10 ^{12 to} 5 × 10 ¹³ atoms /
cm ² to. As a result, the weak N-type regions (410, 41
1, 412) are formed. (FIG. 4 (B))

Next, the active layer of the P-channel TFT (40
3) and a photoresist mask (413) that covers a portion of the active layer (405) of the pixel TFT that is 3 μm away from the end of the gate electrode (409) in parallel with the gate electrode (409). 414).

Then, phosphorus is again implanted by ion doping using phosphine as a doping gas. The dose is 1 × 10 ^{14 to} 5 × 10 ¹⁵ atoms / cm ² . As a result, a strong N-type region (source / drain)
(415, 416) are formed. In the weak N-type region (412) of the active layer (405) of the pixel TFT, the region (417) covered by the mask (414) remains weak N-type because phosphorus is not implanted in this doping. . (FIG. 4 (C))

Next, the active layer of the N-channel TFT (40
4, 405) is covered with a photoresist mask (418), and boron is implanted into the island region (403) by ion doping using diborane (B ₂ H ₂ ) as a doping gas. The dose is 5 × 10 ¹⁴ to 8 × 10 ¹⁵ atoms / c.
and m ^2.

In this doping, the dose of boron exceeds the dose of phosphorus in FIG. 4C, so that the previously formed weak N-type region (410) is replaced by the strong P-type region (4).
Invert to 19). With the above doping, a strong N-type region (source / drain) (415, 416) and a strong P
A type region (source / drain) (419) and a weak N-type region (low-concentration impurity region) (417) are formed. In this embodiment, the width of the low-concentration impurity region (417) is about 3 μm. (FIG. 4 (D))

Thereafter, thermal annealing is performed at 450 to 850 ° C. for 0.5 to 3 hours to recover damage due to doping, activate doping impurities, and recover silicon crystallinity.

Thereafter, a silicon oxide film having a thickness of 300 is formed on the entire surface as an interlayer insulator (420) by a plasma CVD method.
0 to 6000 °. This may be a nitride film or a multilayer film of a silicon oxide film and a silicon nitride film. Then, the interlayer insulator (420) is etched by a wet etching method to form contact holes in the source / drain.

Then, a thickness of 200
A titanium film of 0 to 6000 ° is formed and etched to form electrodes and wirings (421, 422, 42) of peripheral circuits.
3) and pixel TFT electrode / wiring (424, 425)
To form Further, a silicon nitride film (426) having a thickness of 1000 to 3000 ° is formed as a passivation film by plasma CVD, and is etched to form a contact hole reaching the electrode (425) of the pixel TFT.

Finally, a film having a thickness of 500
A pixel electrode (427) is formed by etching and baking an ITO (indium tin oxide) film of about 1500 °. Thus, the peripheral driver circuit and the pixel region can be formed over the same substrate. (FIG. 4E)

FIG. 1 shows a TFT manufactured by the above steps.
This shows a structure in the case where a cell is formed using a substrate. Here, the liquid crystal panel is assembled by changing the spacer application density. The description follows FIG.

As the TFT substrate (102), a substrate manufactured by the process shown in FIG. 4 is used. The glass substrate (101) for the counter substrate is washed and dried. Counter substrate (10
Regarding 1), the same type of material as the substrate on which the TFT is formed can be used.

Next, an ITO (indium tin oxide) film (103) having a thickness of 500 to 1500 ° is formed on the counter substrate by sputtering. Here, the film thickness is set to 120
0 °. Then bake at 150 ° C for 60 minutes,
Cure the ITO film.

The TFT substrate (102) and the counter substrate (10
In 1), various chemicals such as an etching solution and a resist stripping solution used for the surface treatment are sufficiently washed.

Next, an alignment film (105, 106) is attached to the counter substrate (101) and the TFT substrate (102). As a method for attaching the alignment film, there is a method using a spin coater or a method using flexographic printing. As the alignment film material, a material obtained by dissolving about 10% by weight of polyimide in a solvent such as butyl cellosolve or n-methyl 2-pyrrolidone is used.

Then, the alignment films (105, 10) adhered to both the opposing substrate (101) and the TFT substrate (102).
6) Bake. The bake is to heat and send hot air at a maximum operating temperature of about 300 ° C. to bake and harden the polyimide varnish.

Thereafter, the surface of the glass substrate on which the alignment films (105, 106) are adhered is rubbed in a certain direction with a buff cloth (fiber such as rayon nylon) having a bristle length of 2 to 3 mm to form fine grooves. Perform the process.

Thereafter, a spherical spacer (107) of polymer type, silica type or the like is applied to the TFT substrate or the opposite substrate.
Spray. At this time, the spacer application density is changed according to the purpose. As a spacer spraying method, a dry method in which spacers are sprayed without using any solvent can be adopted.

As a method for changing the spacer distribution density, a mask having a stitch-shaped hole corresponding to the change in the distribution density is used. A screen mask used for screen printing is used as the mask.

Here, the above-mentioned mesh pattern is formed on the screen mask by photolithography. A spacer is arranged on the mask. From this state, the spacer is dropped onto the substrate. This method is an application of Japanese Patent Publication No. 61-33166.

The density of the spacers to be sprayed changes according to the density distribution of the screen mask holes. Here, the drop amount of the spacer is reduced in the portion where the stitches are dense, and the spacer application density is reduced. Further, in a portion where the stitches are sparse, the amount of drop of the spacer increases, and the spacer application density increases.

Next, a sealing material (110) is applied to the outer frame of the TFT substrate and the drive circuit area. In order to prevent damage to the drive circuit elements, no filler for controlling the distance between the substrates was mixed in the seal material. The application of the sealing material has a role of bonding the TFT substrate to the counter substrate and a purpose of preventing the injected liquid crystal material from flowing out.

To attach the sealant to the glass substrate, there are a method of applying the sealant from a syringe-shaped dispenser and a method of printing the sealant.

Finally, the counter substrate (101) and the TFT substrate (102) are bonded. Thereafter, a liquid crystal material (not shown) is charged from the liquid crystal injection port, and after the liquid crystal material is injected, the liquid crystal injection port is sealed with an epoxy resin or the like.

Thereafter, the polarizing plates (112, 113) are attached. The angle between the polarizer of the polarizing plate and the analyzer can be arbitrarily set according to the liquid crystal drive mode. As described above, a liquid crystal panel as shown in FIG. 1 can be manufactured.

[Embodiment 2] In this embodiment, an example is shown in which the density of the spacers is changed within the pixel area when forming a cell without using a filler in the sealing material.

In this embodiment, "Micropearl SP" manufactured by Sekisui Fine Chemical is used as a resin spacer.
The spacer diameter is 4.0 μm. The glass substrate used is a Corning substrate. This is 5 inches wide and 5 inches high
Of inches. Use two of them.

Next, spacers are sprayed on one of the substrates. In this embodiment, the spacer is sprayed by a dry method. The equipment used is a dry spacer sprayer manufactured by Nisshin Engineering.

Next, a sealing material is applied as an outer frame on the drive circuit area of the TFT substrate. "XN-21S" manufactured by Mitsui Toatsu is used as a sealing material. No filler for maintaining the distance between the substrates is mixed in the sealing material.

In this embodiment, the spacer application density was changed substantially concentrically from the center of the area surrounded by the sealing material. This is because, in FIG. 5, the cell gap unevenness is seen substantially concentrically from the center of the region surrounded by the sealing material.

The spacer spray density was 50 pieces / pixel at the center of the pixel.
It was mm ^2. Then, the spacer spray density was changed from the pixel center to the vicinity of the sealing material. The spacer spray density near the sealing material was set to 300 pieces / mm ² . This is based on the data in FIG. FIG. 3 shows the relationship between the spacer scatter density and the cell gap distribution when a cell was fabricated under the same conditions as in this example.

More specifically, for example, a line parallel to the horizontal axis is drawn at a cell gap of 4.6 μm in FIG. Then, it is found that it is effective to change the spacer distribution density in order to keep the cell gap at 4.6 μm.

According to FIG. 3, when the distance from the center is 0 inch, 50 pieces / mm ² , when the distance from the center is about 1 inch, 100 pieces / mm ² , and when the distance from the center is about 1.6 inches, 200 pieces / mm ^2. ,
In the case of about 2.2 inches, it is possible to keep the cell gap uniform by setting the spacer distribution density to 300 pieces / mm ² .

The cell gap distribution of the cell manufactured in this example was as shown in FIG. In other words, the uniformity of the cell gap could be kept remarkably as compared with the conventional example by setting the spacer scattering density of the present example. Further, by changing the spacer distribution density as in this example, a uniform cell gap could be maintained even when no filler was used in the sealing material.

The density of the spacers may be changed according to the state of the cells. For example, an area generally surrounded by a sealing material often has a rectangular shape. In this case, the cell is determined in advance by forming cells in which the spacer distribution density is made uniform and considering the cell gap unevenness in that state. Whether or not the spacers are scattered in the sealing material is optional and may be determined according to the state at that time.

[Embodiment 3] In this embodiment, the dispersion density of the spacers is made uniform within the pixel region, and the spacers are gradually formed outside the pixel region between the edge of the pixel region and the sealing material toward the outside of the substrate. A favorable display state was obtained by increasing the scatter density of.

In this embodiment, the cell gap unevenness is small,
Further, an object is to manufacture a panel with few low-luminance defects. The substrate manufactured in Example 1 is used. The finished panel size is 3 inches.

In this embodiment, the silica spacer is
"Shinito Ball-SW" manufactured by Catalyst Chemical Industry was used. Spacer spraying is a dry method. The equipment used is a dry spacer sprayer manufactured by Nisshin Engineering. . The spacer diameter is 4.0 μm. Here, a filler was mixed to maintain the cell gap. The filler concentration is 3.0 wt%.

At this time, outside the pixel area, the density of the spacers was changed between the edge of the pixel area and the sealing material. The spacer distribution density in the pixel area is 30 pieces / mm ² . Further, the density of the spacer scatter at the edge of the pixel area is 30 pieces / m.
m ^2, and the spacer spray density near the seal material is 100
The number of pieces / mm ² was set so that the spacer spray density was changed between them.

Next, a sealing material is applied to the outer frame of the drive circuit section of the TFT substrate. "XN-" made by Mitsui Toatsu as a sealing material
21S "was used. After the application of the sealing material, the two glass substrates were bonded to each other. The method employed a heat curing method in which the sealing material was cured by a high-temperature press at about 160 ° C. in about 3 hours. The pressing pressure during high-temperature pressing is 0.3 kgf /
cm ² .

In this embodiment, the spacer density in the pixel area is as small as 30 pieces / mm ² .
It is possible to sufficiently keep the cell gap uniform. This is to increase the spacer distribution density outside the pixel area,
This is because the cell gap can be precisely controlled.

Therefore, in this embodiment, it is possible to keep the spacer distribution density in the pixel area relatively small as compared with the area outside the pixel area. That is, it is possible to obtain a panel with less cell gap unevenness and reduced occurrence of low-luminance defects due to spacers. This is particularly effective when the panel is used as a projection display.

The state in which the spacers are scattered in this embodiment is an example. The dispersion state of the spacer can be set arbitrarily according to the state of the cell. Further, the configuration of this embodiment can be applied even when no filler is used in the sealing material.

[0100]

According to the present invention, the cell gap unevenness of the liquid crystal display device can be improved. Further, according to the present invention, it is possible to reduce the spacer distribution density of the pixel portion in the liquid crystal display device. This can reduce the occurrence of a low-luminance defect in the display unit due to the spacer.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a liquid crystal display device of the present invention.

FIG. 2 is a diagram showing a cell gap distribution in a substrate in Example 2.

FIG. 3 is a graph showing the dependence of the cell gap on the spacer distribution density in Example 2.

FIG. 4 is a diagram showing a TFT substrate manufacturing process of the first embodiment.

FIG. 5 is a diagram showing a cell gap distribution in a substrate of a conventional example.

DESCRIPTION OF SYMBOLS 101, 102 Substrate 103, 104 Transparent electrode 105, 106 Alignment film 107 Spacer 108 Pixel TFT 109 Drive circuit TFT 110 Sealant 111, 112 Polarizer 113 Pixel region 401 Substrate 402 Underlayer 403-405 Active layer 406 Gate insulating film 407-409 Gate electrode, gate line 410-412 Weak N-type region 413,414 Photoresist mask 415,416 Strong N-type region (source, drain) 417 Low concentration impurity region 418 Photoresist mask 419 Strong P Mold region (source, drain) 420 Interlayer insulating film 421 to 425 Metal wiring, electrode 426 Passivation film 427 Pixel electrode

Claims (10)

[Claims] An electronic device comprising: a pair of substrates, at least one of which is transparent; an electrode formed on at least one of the substrates; and a liquid crystal layer sandwiched between the substrates, wherein a sealing material is provided between the substrates. And a spacer, wherein the density of the spacer on the substrate varies. 2. The dispersion density of the spacer according to claim 1, wherein the distribution density of the spacer is constant in a region where the sealing material is arranged, and the distribution density of the spacer gradually decreases inward from a region surrounded by the sealing material. A liquid crystal display device comprising: 3. The liquid crystal display device according to claim 1, wherein the scatter density of the spacer increases substantially concentrically from the center of the region surrounded by the sealing material. 4. The device according to claim 1, wherein a driving circuit and a pixel region are formed on at least one of the substrates, a sealing material is present on the driving circuit of the substrate, A liquid crystal display device characterized in that no filler is mixed. 5. The dispersion density of the spacer according to claim 4, wherein the distribution density of the spacer is constant in a region where the sealing material is arranged, and the distribution density of the spacer gradually decreases inward from a region surrounded by the sealing material. A liquid crystal display device comprising: 6. The liquid crystal display device according to claim 4, wherein the scatter density of the spacer increases substantially concentrically from the center of the region surrounded by the sealing material. 7. At least one of a pair of transparent substrates, an electrode formed on at least one of the substrates, and a liquid crystal layer sandwiched between the substrates, wherein at least one of the substrates has a pixel region. Is formed, wherein a sealing material and a spacer are arranged between the substrates, wherein the density of the spacers in the pixel region is uniform, and the density of the spacers is increased from the pixel region toward a region outside the pixel region. A liquid crystal display device, wherein a spray density gradually increases. 8. The liquid crystal display device according to claim 7, wherein the distribution density of the spacers in the region surrounded by the sealing material is equal. 9. The driving circuit according to claim 7, wherein a driving circuit and a pixel region are formed on at least one of the substrates, a sealing material is present on the driving circuit of the substrate, A liquid crystal display device characterized in that no filler is mixed. 10. The liquid crystal display device according to claim 9, wherein the density of the spacers in the region surrounded by the sealing material is equal.