JPH0973093A - Liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal display device having good display performance at a high yield by forming columnar spacers at a high density in the regions of the display in the outer peripheral parts of substrates, thereby decreasing the display defects by a cell gap defect. SOLUTION: A counter substrate 2 is constituted by forming black light shielding layers 11 on a glass substrate 10 and three colors of colored layers 12 (R), 12 (G), 12 (B) in the spacings between the black light shielding layers 11. The parts between respective pixels are formed to a matrix shape and the outer periphery parts are formed to a broad band shape. The inner side of the light shielding layers 11 disposed in the outer peripheral parts thereof is formed as the display regions. The parts including the light shielding layers 11 disposed in the outer periphery parts and the side outer than these layers are formed as the regions off the display. The outer side of a sealing material 4 is included in the regions off the display as well and further, the columnar spacers 13 are built into the display regions and the regions off the display of the counter substrate 2. The columnar spacers 13 are formed on the light shielding layers 11 and the density of the number of pieces of the columnar spacers 13 formed in the regions off the display is set higher than the density of the number of pieces of the columnar spacers formed in the display regions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a columnar spacer structure.

[0002]

2. Description of the Related Art At present, in a liquid crystal display device, when two substrates are bonded together in a forming process, a sealing material is applied to one of the two substrates and the other substrate is overlaid, and a pressing device is used. A method of curing the sealing material while applying pressure is used. At this time, a strong pressure is likely to be applied to the outer peripheral portion of the substrate, so that the substrate spacing in the outer peripheral portion is likely to be small, which may cause display defects due to defective cell gaps. On the other hand, when the spacer density on the entire surface of the substrate is increased as a countermeasure against the cell gap defect, there is a problem that vacuum bubbles are easily generated in the liquid crystal layer.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display device which reduces display defects due to cell gap defects and has a high yield and good display performance. To do.

[0004]

According to the structure and manufacturing method of the liquid crystal display device of the present invention, the columnar spacers are formed at a high density in the non-display area of the peripheral portion of the substrate, or the columnar spacers of the non-display area are thickened. By forming, even if a strong pressure is applied to the outer peripheral portion of the substrate at the time of bonding the substrates,
It can withstand strong pressure and does not reduce the outer gap.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a cross-sectional view of the liquid crystal display device of this embodiment, and FIG. 2 is a plan view showing an array pattern.
FIG. 3 shows a thin film transistor (TFT).
7 is an enlarged cross-sectional view of a Transistor) 6 portion.
Note that FIG. 1 is a sectional view taken along the line AA ′ in FIG.
First, an array substrate 1 which is a lower substrate and a counter substrate 2 which is an upper substrate are arranged in parallel, sandwiching a liquid crystal 3 and sealed by a sealing material 4.

First, in the array substrate 1, TFTs 6 (FIGS. 2 and 3) are formed as switching elements on a glass substrate 5 having a thickness of 1.1 mm, and the pixel electrodes 7 are connected to the TFTs 6. The alignment film 8 is formed on the uppermost layer. Further, the array substrate 1 is formed with a dummy pattern 25 for adjusting the height to a portion where the columnar spacers 13 formed on the counter substrate 2 come into contact when it is later bonded to the counter substrate 2.

Next, the counter substrate 2 is a glass substrate 10 having a thickness of 1.1 mm, and black colored light-shielding layers 11 and colored layers 12 (R), 12 of three colors of R, G, B in a gap between the light-shielding layers 11. (G), 1
2 (B) is formed. The light-shielding layer 11 is formed in a matrix shape between the pixels and in a wide band shape in the outer peripheral portion.
Then, the inside of the light shielding layer 11 arranged on the outer peripheral portion is set as a display area, and the outer side including the light shielding layer 11 arranged on the outer peripheral portion is set as an outer display area. The non-display area also includes the outside of the sealing material 4. Further, on the counter substrate 2, columnar spacers 13 are formed in the display area and the non-display area. The columnar spacers 13 are formed on the light-shielding layer 11, and the density of the columnar spacers 13 formed in the non-display area is higher than the density of the columnar spacers formed in the display area. Further, a common electrode 14 is formed on the entire surface of the counter substrate 2, and an alignment film 15 is formed on the uppermost layer.

The first substrate of the present invention corresponds to the counter substrate 2 in this embodiment, and similarly, the second substrate is the array substrate 1
In addition, the first transparent electrode corresponds to the common electrode 14, and the second transparent electrode corresponds to the pixel electrode 7.

Next, the manufacturing process of the liquid crystal display device of this embodiment will be described. First, the manufacturing process of the counter substrate 2 will be described. A photosensitive black resin is applied onto a glass substrate 10 having a thickness of 1.1 mm using a spinner or the like, dried at about 90 ° C. for 10 minutes, and then exposed using a photomask having a predetermined pattern shape, Develop with alkaline solution, 200 ℃
By baking for 60 minutes, the light shielding layer 11 having a film thickness of about 2.0 μm is formed.

Next, an ultraviolet-curable acrylic resin in which a red pigment is dispersed is applied by a spinner, and a photomask is irradiated so that the portion to be colored red and the portion to form the columnar spacer 13 are irradiated with ultraviolet rays. Irradiate with ultraviolet light through, for example, develop with a 1% aqueous solution of KOH for about 10 seconds,
Red colored layer 12 (R) and columnar spacer 13 having a three-layer structure
Forming one layer of. Here, the outer peripheral portion of the substrate will be cut off later, but the columnar spacers 13 are also formed in the cut-off region. (Refer to FIG. 4) This has an effect that a cell gap defect is less likely to occur at the time of bonding. Similarly, for green and blue, the colored layers 12 (G) and 12 (B) are repeatedly formed on the portions to be colored and the portions on which the columnar spacers 13 are to be formed, and each is baked at 230 ° C. for 60 minutes. In this manner, the colored layers 12 (R), 12 (G), 12 (B) and the columnar spacer 13 are formed. At this time, the red, green, and blue colored layers 12
(R), 12 (G), and 12 (B) have film thicknesses of 1.
The diameter of the pillar of the pillar spacer is 10 μm for 12 (R), 13 μm for 12 (G), and 16 μ for 12 (B).
The upper layer was thicker in m. By doing so, the columnar spacers 13 have a reverse taper shape, and when the common electrode 14 is coated on the entire surface of the substrate later, it becomes difficult for the common electrodes 14 to be attached to the side surfaces of the columnar spacers 13. The chance of conduction is very small. Then, about 30 per display area 1 mm ^2, the non-display region to form about 60 columnar spacer per 1 mm ^2.
At this time, the columnar spacers 13 are formed on the light shielding layer 11, and the columnar spacers 13 formed in the display region are further formed.
Is arranged so as to be on the gate line 20 or the signal line 30 when it is bonded to the array substrate 1, and the non-display area is arranged so as to be on the dummy pattern 25 in order to adjust the height. ing. In the display region of the columnar spacer 13 in this embodiment, the gate insulating film 21 and the signal line 30 are provided.
In addition, the non-display area is covered with the gate line 20 and the gate insulating film 21.
It is on the top 25 of the dummy pattern. Further, since the columnar spacer 13 becomes an obstacle in the rubbing process later and a shadow area of the rubbing is formed, the shadow area is settled in the area of the light shielding layer 11 so as not to affect the display. It is also necessary to consider the arrangement of the columnar spacers 13.

By forming the columnar spacers 13 at the same time as the colored layer 12 as in the present embodiment, the number of steps for forming the spacers can be reduced by one, but the colored layer can be formed without forming the spacers at the same time. After that, a resin not containing a pigment may be separately formed.

Thereafter, ITO (In
1Din Tin Oxide) film by sputtering method
Form to a thickness of 500 Å. On top of this,
For example, polyimide is formed and a rubbing process is performed to form the alignment film 15, and the counter substrate 2 is completed.

Next, the method for manufacturing the array substrate 1 has a thickness of 1.
The TFT 6 is formed by repeating film formation and patterning on the 1 mm glass substrate 5. As shown in FIG. 3, a gate line 20 made of MoW (molybdenum / tungsten) or MoTa (molybdenum / tantalum), an auxiliary capacitance line (not shown), and a lead-out electrode for transfer integrated with the auxiliary capacitance line are formed. SiO _x is deposited at a heat of 4000 angstrom by plasma CVD method to form a gate insulating film 21. Here, a dummy pattern 25 is formed by the gate line 20 and the gate insulating film 21 for height adjustment at a position where the columnar spacer 13 formed on the counter substrate 2 is abutted when it is later bonded to the counter substrate 2. I'll do it. The dummy pattern 25 may be formed by the gate insulating film 21 and the signal line 30.

A semiconductor layer 22 made of a-Si (amorphous silicon) is formed thereon by a plasma CVD method and patterned into a predetermined shape. Further, depending on the case, an electrode made of Mo / Al / Mo is formed via an n ⁺ a-Si ohmic contact layer (not shown), and patterned into a desired shape to form the source electrode 2
3, the drain electrode 24 is formed.

Next, the pixel electrode 7 is formed by patterning the transparent electrode ITO so as to contact the source electrode 23. Finally, polyimide or the like is formed and a rubbing process is performed to form the alignment film 8.

After that, the sealing material 4 is printed along the periphery of the alignment film 15 of the counter substrate 2 except the injection port. Next, the alignment film 8 of the array substrate 1 and the alignment film 15 of the counter substrate 2 face each other and are stacked so that the rubbing direction forms an angle of 90 °, and the sealing material 4 is hardened and bonded by heating. To match.

Next, the liquid crystal 3 can be injected by placing an empty cell in a vacuum and gradually returning the vacuum state to atmospheric pressure with the liquid crystal material immersed in the inlet. And
The desired liquid crystal display device in this embodiment is obtained by cutting off the outer peripheral portion of the substrate.

Although this embodiment is an active matrix type liquid crystal display device using a TFT array substrate and has a structure in which a light shielding layer is formed on the counter substrate side, the present invention forms the light shielding layer on the array substrate. It is also applicable to a liquid crystal display device having the above structure. In this case, the substrate on which the columnar spacer is formed may be different from the substrate on which the light shielding layer is formed.

Further, the structure of the TFT is not limited to the inverted staggered type as in the present embodiment, and it is also applicable to a simple matrix type liquid crystal display device having striped electrodes on the upper and lower substrates.

As described above, it goes without saying that many changes and modifications can be added to this embodiment. (Embodiment 2) In this embodiment, as shown in FIG.
The non-display area of the counter substrate 2 is divided into two areas, that is, the area (D1) near the display area and the area (D2) far from the display area, and the density of the number of columnar spacers is
About 30 in the display area is 1 mm ^2, D1 is about to 1 mm ² 45
And D2 was about 60 per 1 mm ² .

It should be noted that the density may be gradually increased as the distance from the display area is increased without clearly dividing the areas as D1 and D2. Other configurations and the like are similar to those of the first embodiment.

According to this embodiment, it is possible to prevent vacuum bubbles, which are easily generated by increasing the density of the columnar spacers 13, from being generated in the vicinity of the display area, and also to reduce cell gap defects. .

(Embodiment 3) In this embodiment, as shown in FIG. 6, the volume of the columnar spacer 13 is changed between the display area and the non-display area. In the case of a liquid crystal display device, since the two substrates are arranged substantially in parallel, it can be said that changing the volume of the columnar spacer is substantially synonymous with changing the thickness of the columnar spacer. However, this is not the case when the columnar spacer has a tapered shape or the columnar spacer has a thickness that changes in the middle.

In the present embodiment, the diameter of 12 (R) forming the columnar spacers 13 is about 10 μm and 12 in the display area.
The diameter of (G) is about 13 μm, and the diameter of 12 (B) is about 16 μm.
In the non-display area, the diameter of 12 (R) is about 20 μm, the diameter of 12 (G) is about 26 μm, and 12 (B).
Columnar spacer 1 with a diameter of about 32 μm
3 was formed.

Other configurations are similar to those of the first embodiment. (Fourth Embodiment) In this embodiment, as shown in FIG. 7, the non-display area is divided into the area D3 near the display area and the area far from the display area. The columnar spacer 1 is divided into a region D4 and a display region.
The diameter of 12 (R) forming 3 is about 10 μm, 12
The diameter of (G) is about 13 μm, and the diameter of 12 (B) is about 16 μm.
The diameter of 12 (R) is about 15 μm, and the diameter of 12 (G) is about 20 μm in D3 of the non-display area.
A columnar spacer 13 having a diameter of (B) is formed with a thickness of about 24 μm, and a diameter of 12 (R) is about 20 μm and a diameter of 12 (G) is about 26 μm in D4 of the non-display area.
A columnar spacer 13 having a diameter of 2 (B) and a thickness of about 32 μm was formed.

Incidentally, the diameter of the columnar spacer may be gradually increased as the distance from the display area is increased without dividing the area clearly like D3 and D4.
(See FIG. 8) Other configurations and the like are similar to those of the first embodiment. Needless to say, each embodiment can be modified in various ways, such as a structure in which the light-shielding layer is formed on the array substrate, as in the first embodiment.

[0027]

According to the present invention, it is possible to provide a liquid crystal display device having a good display performance at a low cost by improving the poor yield due to the defective cell gap caused by the bonding.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an array pattern of a liquid crystal display device according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing a structure of a thin film transistor of a liquid crystal display device according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention, showing a columnar spacer and a dummy pattern formed in a region to be cut off in the outer peripheral portion of the substrate.

FIG. 5 is a sectional view of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view of a liquid crystal display device in a modified example of Example 4 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Array substrate 2 ... Counter substrate 3 ... Liquid crystal 4 ... Sealing material 5, 10 ... Glass substrate 6 ... Thin film transistor 7 ... Pixel electrode 8, 15 ... Alignment film 11 ... Light-shielding layer 12 (R), 12 (G), 12 ( B) ... Colored layer 13 ... Columnar spacer 14 ... Common electrode 20 ... Gate line 21 ... Gate insulating film 25 ... Dummy pattern 30 ... Signal line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shoichi Kurauchi, 8 Shinsitada-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Yokohama Corporation, Ltd. (72) Inventor, Teruyuki Midorikawa 7-1, Nisshin-cho, Kawasaki-ku, Kawasaki, Kanagawa Shiba Electronics Engineering Co., Ltd.

Claims (11)

[Claims] 1. A liquid crystal is sandwiched between a first substrate and a second substrate, and the first substrate is provided with a plurality of columnar spacers for maintaining a space between the first substrate and the second substrate. A liquid crystal display device comprising: a first transparent electrode for applying a voltage to the liquid crystal; and a second transparent electrode for applying a voltage to the liquid crystal on the second substrate, wherein the liquid crystal display device is provided on an outer peripheral portion. There is a non-display area that does not perform display and a display area that performs display inside thereof, and the density of the number of the columnar spacers formed in the non-display area is equal to that of the columnar spacers formed in the display area. A liquid crystal display device having a higher density than the number of liquid crystal display devices. 2. The liquid crystal display device according to claim 1, wherein the density of the number of columnar spacers formed in the non-display area increases as the distance from the display area increases. 3. The non-display area is divided into a plurality of areas according to a distance from the display area, and the area farther from the display area among the divided areas has a higher density of the columnar spacers. Item 3. The liquid crystal display device according to item 1. 4. A liquid crystal is sandwiched between a first substrate and a second substrate, and the first substrate is provided with a plurality of columnar spacers for keeping a distance between the first substrate and the second substrate. A liquid crystal display device comprising: a first transparent electrode for applying a voltage to the liquid crystal; and a transparent electrode for applying a voltage to the liquid crystal on the second substrate, wherein the liquid crystal display device performs display on an outer peripheral portion. There is a non-display area and a display area for displaying inside, and the volume of the columnar spacer formed in the display area is larger than the volume of the columnar spacer formed in the display area. Characteristic liquid crystal display device. 5. The liquid crystal display device according to claim 4, wherein the volume of the columnar spacer formed in the non-display area increases as the distance from the display area increases. 6. The non-display area is divided into a plurality of areas according to a distance from the display area, and a volume of the columnar spacer is larger in a region farther from the display region among the divided regions. The described liquid crystal display device. 7. The liquid crystal display device according to claim 1, wherein a dummy pattern is formed on a region of the second substrate which is in contact with the columnar spacer. 8. A liquid crystal is sandwiched between a first substrate and a second substrate, and the first substrate and the second substrate are attached to the first substrate.
A plurality of columnar spacers for keeping a distance from the substrate and a first transparent electrode, and the second substrate includes a thin film transistor including a gate line, a gate insulating film and a signal line, and a second transparent electrode. A method of manufacturing a liquid crystal display device comprising: forming a dummy pattern in a region corresponding to the columnar spacer, which is a part of a process of forming the thin film transistor. Method for manufacturing liquid crystal display device. 9. The step of forming the dummy pattern comprises:
9. The method for manufacturing a liquid crystal display device according to claim 8, comprising a step of forming the gate line and a step of forming the gate insulating film. 10. The method of manufacturing a liquid crystal display device, wherein the step of forming the dummy pattern includes a step of forming the gate insulating film and a step of forming the signal line. 11. A liquid crystal is sandwiched between a first substrate and a second substrate, and the first substrate includes a plurality of columnar spacers for keeping a distance between the first substrate and the second substrate. , First
A step of forming the columnar spacers on the first substrate, and a step of forming a dummy pattern in a region of the substrate of the striking 2 where the columnar spacers contact, In a method of manufacturing a liquid crystal display device, including a step of bonding the first substrate and the second substrate, and a step of cutting off the bonded first and second substrates, forming a columnar spacer In the step of forming the columnar spacer in the cut-off region of the first substrate and forming the dummy pattern, the dummy pattern is also formed in the region where the columnar spacer formed in the cut-out region hits. A method for manufacturing a characteristic liquid crystal display device.