JP2000035583A - Manufacturing method of flat display device and flat display device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the yield by suppressing damage to an alignment film due to spacer pillars to reduce alignment defects. SOLUTION: In a liquid crystal display device in which a gap between two substrates 11 and 21 sandwiching a liquid crystal is held by a spacer column 25, a spacer column having a truncated pyramid shape made of photoresist is disposed on one substrate 21. A projection 27 projecting upward is formed around the top surface 26 of the spacer pillar, and the alignment film 1 of the substrate is opposed to the projection 27 of the spacer pillar in the substrate alignment step.
6, so that even if the alignment film 16 may be damaged, it is minimized so as not to substantially affect the liquid crystal alignment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flat panel display, and more particularly to a liquid crystal display.

[0002]

2. Description of the Related Art A liquid crystal display device, which is a kind of flat display device, is widely used as a display device for TV and OA because of its thinness and light weight. The liquid crystal display device has a structure in which a liquid crystal layer is sandwiched between two glass substrates on which a number of pixels are formed, and a spacer is inserted between the substrates in order to ensure the thickness of the liquid crystal layer accurately. As a typical spacer arrangement, there is a method of dispersing spherical fine particles between the substrates. However, it is inevitable that the spacer blocks the pixel opening, and a pixel defect occurs.

In order to prevent this, there has been proposed a method of maintaining a gap between substrates by disposing a resin spacer pillar in a non-opening portion that partitions pixels on one substrate. The use of the spacer columns is effective in improving the quality of the liquid crystal display device, reducing costs, saving processes, and the like.

[0004]

In a liquid crystal display device, an alignment film for aligning a liquid crystal layer is applied to both substrate surfaces. In a cell assembling process before injecting liquid crystal, both alignment processed substrates are cleaned. Then, a sealant is applied to the periphery of one of the substrates, and the substrates are bonded by a substrate bonding machine (mounter) by two operations of temporary positioning and final positioning. In the temporary bonding, the top of the spacer pillar arranged on one substrate may come into contact with the pixel opening, and the temporary bonding is a rough alignment,
Alternatively, when the position of the spacer column is displaced in the main alignment when the accuracy of the mounter is not good, the alignment film of the other substrate may be damaged, resulting in poor alignment of the liquid crystal.

[0005] In the conventional spacer column shape, the truncated pyramid apex makes surface contact, so that the orientation disorder of the contact portion becomes large,
If the light is turned on in a cell or a module, a display failure occurs.

An object of the present invention is to prevent a display defect due to such contact of the spacer pillar with the opening of the substrate.

[0007]

According to the present invention, two substrates having an electrode for forming a pixel and an alignment film are arranged so that the alignment films face each other, and spacer pillars are formed on the one substrate. In the method of manufacturing a flat display device, the top surface of the spacer pillar is brought into contact with the other substrate to hold a gap between the two substrates, and the periphery of the substrate is bonded with a sealant. The present invention relates to a method for manufacturing a flat panel display device, comprising a projection formed on at least a part of a periphery of a top surface of a spacer column.

In the method of manufacturing a flat display device, the spacer pillar may be crushed when the two substrates are bonded, and the top surface may contact the other substrate.

[0009] Further, there is provided a method for manufacturing a flat display device, wherein the spacer pillar is formed in a non-opening portion between the pixels.

Also, a top surface is arranged to hold a gap between two substrates having electrodes for forming pixels and a liquid crystal alignment film, and a spacer pillar formed on one substrate and in contact with the other substrate is in contact therewith. In a flat panel display device having a projection formed thereon.

As described above, according to the present invention, for example, a projection is provided around the top surface of a truncated pyramid-shaped spacer column.
At the time of bonding by a mounter or the like, the opposing substrate and this projection are brought into point contact. As a result, even if the spacer pillars come into contact with the openings and the spacer pillars come into contact with the openings, they are in point contact with each other. Therefore, even if the cells or the modules are turned on, it is not possible to visually confirm display defects. Further, the projections are crushed by the sealing after assembly, and the tops of the spacer pillars become flat, so that the gap between the color filter substrate and the electrode substrate can be supported.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) As shown in FIGS. 1 to 4, this embodiment is an active matrix type liquid crystal display device, and a first substrate 11 made of glass forming a 12-inch array substrate. And the second of the glass forming the opposing substrate.
The substrates 21 are held opposite to each other with a predetermined gap by a sealant 30. The array substrate 11 has wirings 13 such as signal lines and scanning lines, switching thin film transistors 14 and pixel electrodes 15 formed on the substrate, and a liquid crystal alignment film 16 made of polyimide is coated thereon. A circuit 17 and an electrode pad 18 are formed.
As shown in FIG. 2, the wiring 13 extends to a non-opening between the pixel electrodes 15, and a region of each pixel electrode 15 becomes an opening of the pixel.

The opposing substrate 21 includes a color filter 22, an IT
A common electrode 23 made of an O transparent conductive film and a liquid crystal alignment film 24 are formed on the common electrode 23. The color filter 22 includes a red filter 22R, a green filter 22G, and a blue filter 22B.
Are sequentially arranged, and a light absorber 22BM is arranged between the filters.

As shown in FIG. 3, a spacer column 25 is provided on the light absorbing body 22BM on the counter substrate 21, and a set of red, green, and blue pixels corresponding to the positions of the non-opening portions shown in FIG. Placed in

As shown in FIG. 4, the spacer pillar 25 has a truncated pyramid shape with a bottom area of 20 μm × 15 μm, and has an edge-like projection 27 protruding above the top surface 26 around the top surface 26.
The spacer pillar 25 can be formed of a photoresist, and a resist film of an acrylic resin formed on one surface of the substrate is patterned by photoetching. The edge protrusion 27 can be realized by adjusting the exposure time of the photoresist. For example, ultraviolet irradiation, 300 mJ / cm ²
When light irradiation is performed twice or more, for example, at 1000 mJ / cm ² to form a spacer column, a burr-like edge-shaped protrusion can be formed on the periphery of the truncated pyramid. Since this projection is narrow and has a sharp tip, even if it comes into contact with the alignment film 16 on the array substrate, the area in contact with the alignment film is small and the area that damages the alignment film is small. Further, since the two substrates are mechanically weak and have flexibility, when the two substrates are opposed to each other with a gap therebetween, the protrusion is crushed and the retention of the gap is substantially determined by the distance h to the top surface 26 of the spacer column. If the gap is, for example, 5 μm for obtaining the thickness of the liquid crystal layer, the distance h may be determined accordingly.

The two substrates 11 and 21 are bonded together by applying a sealant 30 to the periphery of the counter substrate 21 and temporarily aligning the two substrates on a mounter such that the respective alignment films face each other. Attach at proper position.

When a cell was manufactured using such a spacer column and evaluated, it was found that when the bonding accuracy of the mounter was poor and the top of the spacer column contacted the pixel opening, the four corners of the top were point-contacted with a microscope. However, poor display could not be confirmed with the naked eye.

(Embodiment 2) FIG. 5 shows this embodiment. An amorphous silicon film 41 and a gate insulating film 42 are stacked on the array substrate 11, a gate line 43 serving as a gate electrode and an interlayer insulating film 44 are formed thereon, and a drain electrode 45 is formed on the amorphous silicon 41 through a through hole.
The source electrode 46 is connected. This constitutes a thin film transistor (TFT). A protective film 47 is coated on the interlayer insulating film 44, a light-shielding film 48 is provided in a region of the thin film transistor on the upper surface thereof, and a transparent film of ITO connected to the source electrode 46 is arranged as the pixel electrode 15. The protection film 47 is formed of a low-temperature oxide film of silicon or the like.
8 is also formed of an inorganic film or the like. This light shielding film 48
A large number of minute spacer columns 50 are formed on the array substrate 11 to maintain a gap between the array substrate 11 and the counter substrate 21. The uppermost layer is covered with a liquid crystal alignment film 16, and an alignment process is performed.

A color filter 22, a common electrode 23 of ITO and a liquid crystal alignment film 24 are adhered to one surface of the counter substrate 21, and an alignment process is performed on the surface of the liquid crystal alignment film.

The substrates 11 and 21 are sealed with a sealing agent at a predetermined gap by spacer columns 50 so that the surfaces on the respective electrode forming sides, that is, the alignment film surfaces are opposed to each other. The gap is filled with a liquid crystal composition and sandwiched as a liquid crystal layer 60.

The spacer column 50 is made of a negative photosensitive organic resin (manufactured by Nippon Synthetic Rubber Co., Ltd.) of 6.0 μm by spin coater.
And exposed to ultraviolet light at 1000 mJ / cm ² and developed with a weak alkaline solution (TMAH (tetramethylammonium hydride) 0.5% aqueous solution) to form columns with protrusions 51. . further,
Curing is performed at 200 ° C. in an oven to stabilize and form spacer pillars.

When the cell having the spacer pillar was evaluated, no defective display could be confirmed with the naked eye even when the top of the spacer pillar was in contact with the pixel opening during the temporary alignment.

The same effect can be obtained by forming the spacer column from a truncated pyramid as described above, or from a conical prism or column.

[0025]

According to the spacer pillar of the present invention, since the spacer pillar reduces the alignment failure due to the contact with the opening of the counter substrate, the yield of the liquid crystal cell is improved. In addition, it is not necessary to improve the bonding accuracy with a mounter for bringing the spacer pillar into contact with the non-opening portion, so that the cost of remodeling the manufacturing apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating Embodiment 1 of the present invention,

FIG. 2 is a plan view of a part of the first embodiment of the present invention,

FIG. 3 is a partial cross-sectional view of Embodiment 1 of the present invention;

FIG. 4 shows a spacer column according to the first embodiment of the present invention;
(A) is a plan view, (b) is a cross-sectional view taken along line AA, (c) is a cross-sectional view taken along line BB,

FIG. 5 is a partial cross-sectional view of Embodiment 2 of the present invention.

[Explanation of symbols]

 11: Array substrate 15: Pixel electrode 16: Alignment film 21: Counter substrate 22: Color filter 23: Common electrode 24: Alignment film 25: Spacer pillar 26: Top surface 27: Projection

Continuation of the front page F term (reference) 2H089 LA09 LA10 LA16 MA04X NA14 QA16 TA09 TA12 TA13 5C094 AA01 AA31 AA42 AA43 AA44 DA03 EA04 EC03 FA02

Claims (4)

[Claims] 1. An electrode for forming a pixel and two substrates having an alignment film are arranged so that the alignment films face each other, a spacer column is formed on the one substrate, and the spacer column is formed on the other substrate. In a method of manufacturing a flat display device in which a top surface of the spacer pillar is abutted to hold a gap between the two substrates and a periphery of the substrate is bonded with a sealant, the periphery of the top surface of the spacer pillar abutting the other substrate A method of manufacturing a flat panel display device, wherein a projection projecting from the top surface is formed at least partially. 2. The method according to claim 1, wherein the spacer pillar is configured such that when the two substrates are bonded together, the projection is crushed and the top surface abuts on the other substrate. 3. The method according to claim 1, wherein the spacer pillar is formed in a non-opening between the pixels. 4. A top surface which is arranged to hold a gap between two substrates having an electrode forming a pixel and a liquid crystal alignment film, and which is formed on one substrate and which comes into contact with a spacer column which is in contact with the other substrate. A flat display device having projections formed on the flat display device.