JP2002318387A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve display quality and production efficiency of a liquid crystal display device by proposing a transfer post causing no display defect due to difference in a gap between itself and a spacer or a sealant defining the cell gap. SOLUTION: A recessing part 7 is provided on a place of one out of a pair of substrates where the transfer post 6 is arranged. When a height of the transfer post 6, a height of the recessing part 7 and a diameter of the spacer 4 are represented by a, b and c respectively, the heights of the transfer post 6 and the recessing part 7 are defined so as to satisfy an inequality a-c>=b. Thereby the liquid crystal display device with the high display quality, hardly influenced by the spacer 4 and the sealant 5 defining the cell gap and causing no display defect due to the difference in the gap between the transfer post 6 and them is obtained. Also the transfer post 6 is not influenced by a thermo compression condition unlike a conventional transfer material because it is patterned with photoengraving and consequently its height is easily controlled and the productivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device, and more particularly to a transfer column for electrically connecting a TFT array substrate and a counter electrode substrate.

[0002]

2. Description of the Related Art In a liquid crystal display device, a liquid crystal is arranged between a pair of electrode substrates, for example, a TFT array substrate and a counter electrode substrate, and a voltage is applied between the electrodes of these substrates to control the movement of the liquid crystal and display. Is what you do. Conventionally, in order to apply a voltage to the electrodes of the pair of substrates, a power supply is connected to only one of the substrates, these substrates are electrically connected by transfer posts arranged at the peripheral portion of the substrate, and the other substrate is connected to the other substrate. Was also applying voltage. FIG. 4 is a cross-sectional view schematically showing a liquid crystal display device using a conventional general transfer support. In the drawing, reference numeral 1 denotes a TFT array substrate on which a plurality of thin film transistors and pixel electrodes are arranged in a matrix, 2 denotes a common electrode, a color filter, and the like.
A counter electrode substrate disposed opposite to the array substrate 1 at a fixed distance, 3 is a liquid crystal disposed between a pair of substrates, 4 is a spacer for defining a gap between the pair of substrates, and 5 is a device for bonding the pair of substrates. A sealing material for determining an injection region of the liquid crystal 3;
It contains a spacer not shown. Further, reference numeral 6a denotes a transfer column for electrically connecting the pair of substrates.
A conventional general transfer support 6a is formed by transferring a viscous transfer material, for example, a paste-like mixture of an acrylic or epoxy-based organic resin and silver powder (hereinafter referred to as a silver paste) to the TFT array substrate 1 or the counter electrode substrate. It was formed by applying a liquid to a peripheral portion of one of the substrates 2 using a dispenser or the like, applying heat to cure the substrate, and pressing both substrates together. FIG. 5 is a cross-sectional view schematically showing a liquid crystal display device using another conventional transfer support. In the figure, reference numeral 6b denotes a transfer column formed by depositing a transfer material by a sputtering method or a CVD method and forming a pattern by a photoengraving method. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

[0003]

However, in the case of the transfer column 6a made of silver paste, the transfer column 6a is not provided due to variations in the thermocompression bonding conditions in the plane of the substrate.
The difference occurs in the curing speed of the material a. In addition, the sealing material 5 similarly has a difference in curing speed due to a variation in thermocompression bonding conditions. Therefore, the material of the transfer support 6a and the sealing material 5
If the two curing speeds are different from each other, and there is a variation in each, there is a problem that a gap difference occurs around the transfer pillar 6a forming portion and the seal material 5 forming portion, and display defects such as gap unevenness occur. In the case of the transfer support 6b patterned by the photoengraving method,
Although it is not affected by the thermocompression bonding conditions, it is necessary to form the spacer exactly in height with the spacer 4 disposed in the display unit or the spacer included in the sealing material 5, and it is difficult to control the cell gap value. It has not been put to practical use.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is less susceptible to the influence of a spacer or a sealing material for defining a cell gap, and does not cause display failure due to a gap difference therefrom. An object of the present invention is to propose a support and to improve display quality and productivity of a liquid crystal display device.

[0005]

A liquid crystal display device according to the present invention has a TFT array substrate on which a plurality of thin film transistors and pixel electrodes are arranged in a matrix, a common electrode and a color filter, and is fixed to the TFT array substrate. A counter electrode substrate, which is disposed to be opposed at a distance, a liquid crystal, which is disposed between the pair of substrates, and a spacer, which is disposed between the pair of substrates and defines a gap between the pair of substrates, and adheres the pair of substrates. A sealing material that determines the liquid crystal injection region, and a concave portion formed in the peripheral portion of one of the pair of substrates,
A transfer column is provided between the substrate and a peripheral portion of the other substrate facing the concave portion and electrically connects the pair of substrates. Also, the height of the transfer support is a,
When the height of the recess is b and the spacer diameter is c, a−c ≧
The height of the transfer column and the concave portion is set so as to be b. Also, the transfer support is gold,
It is made of a material such as silver, platinum or copper. Further, the transfer support is formed by depositing a transfer support material on a substrate by a sputtering method, a CVD method, or the like, and forming a pattern by a photoengraving method. The transfer support is provided on either the inside or the outside of the sealing material. In addition, the concave portion is formed by making the thickness of the substrate on which the concave portion is provided or the thickness of any one of the film formation layers on the substrate smaller than other portions.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view schematically showing the liquid crystal display device according to the first embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of the liquid crystal display device shown in FIG. In the figure, reference numeral 1 denotes a TFT array substrate on which a plurality of thin film transistors (see FIG. 3) and pixel electrodes are arranged in a matrix, and 2 has a common electrode, a color filter, and the like, and faces the TFT array substrate 1 at a certain distance. The disposed counter electrode substrate, 3 is a liquid crystal disposed between a pair of substrates, 4 is disposed between a pair of substrates, and a spacer that defines a gap between the pair of substrates, that is, a cell gap, and 5 adheres the pair of substrates. In addition, it is a sealing material for determining an injection region of the liquid crystal 3 and includes a spacer (not shown). Also, 6
Is provided at a predetermined position in a peripheral portion between the pair of substrates, and is a transfer column electrically connecting the pair of substrates. Reference numeral 7 is one of the pair of substrates. In the present embodiment, the transfer column is a transfer column 6 of the TFT array substrate 1. A concave portion provided at the arrangement location,
Reference numeral 8 denotes an alignment control film provided on each of the opposing surfaces of the pair of substrates. Reference numeral 9 denotes an IT control
An extraction electrode 18a made of an O film 17a and a silicon nitride film 18a forming an interlayer insulating film described later. FIG. 3 is a cross-sectional view showing a structure of a thin film transistor formed on the TFT array substrate 1. In the figure, 11 is a transparent insulating substrate, 12 is a gate electrode, 14 is a gate electrode 12
A semiconductor layer provided thereon with a gate insulating film 13 interposed therebetween;
The semiconductor layer 13 and the source electrode 15 and the drain electrode 1
6 constitute a thin film transistor. further,
Reference numeral 17 denotes a pixel electrode made of an ITO film 17a, and reference numeral 18 denotes an interlayer insulating film made of a silicon nitride film 18a having a contact hole 19 for connecting the drain electrode 16 and the pixel electrode 17.

A method of manufacturing a liquid crystal display device according to the present embodiment will be described with reference to FIGS. First, the TFT array substrate 1 is formed. After depositing a metal film made of Cr or the like on the transparent insulating substrate 11 by a sputtering method or the like, patterning is performed to form a gate electrode 12 and a gate wiring (not shown). Next, after depositing the gate insulating film 13 and the semiconductor layer 14 by a plasma CVD method or the like, the semiconductor layer 14 is patterned. Next, a metal film made of Cr or the like is deposited by sputtering or the like, and is patterned to form a drain electrode 1.
6, a source electrode 15 and a source wiring (not shown) are formed. Subsequently, a film thickness of 0.1 μm is formed by a plasma CVD method or the like.
Then, a contact hole 19 is formed by forming an interlayer insulating film 18 made of a silicon nitride film 18a having a thickness of m. At this time, by preventing the silicon nitride film 18a from covering the region of the lead electrode 9 formed in the peripheral portion of the substrate later,
0.1μ height at the position corresponding to the transfer post 6 position
m concave portions 7 are formed. Further, an ITO film 17a is formed to a thickness of 0.05 to 0.1 μm by a sputtering method or the like.
The pixel electrode 17 is formed by patterning, and is connected to the drain electrode 16 via the contact hole 19. Also,
At this time, a lead electrode 9 made of an ITO film 17a is also formed around the substrate. Through the above steps, the TFT array substrate 1 having pixels for applying a voltage to the liquid crystal 3 is completed.

Next, a counter electrode substrate 2 is formed. A color filter layer having R, G, and B color layers and a light-shielding layer (all not shown) are formed on a transparent insulating substrate, and a common electrode (not shown) made of an ITO film is formed on the entire surface of the substrate. ) Is formed. Next, silver (Ag) is deposited by sputtering at a plurality of predetermined positions around the counter electrode substrate 2, in this embodiment, outside the sealing material 5 formed later.
A transfer support 6 having a height of 4.6 μm is formed by pattern formation by photolithography.

Next, an alignment control film 8 is formed on the surface of the TFT array substrate 1 and the counter electrode substrate 2 to a thickness of 0.05 μm, respectively, and a rubbing treatment is performed in a predetermined direction. At this time, the orientation control film 8 is not formed on the portion of the extraction electrode 9 of the TFT array substrate 1 and the portion of the transfer support 6 of the counter electrode substrate 2, and the extraction electrode 9 and the transfer support 6 are exposed. Subsequently, a bead-shaped spacer 4 having a diameter of 4.4 μm, which defines a cell gap, is sprayed on one of these substrates. Further, a sealing material 5 including a spacer for keeping a space between the substrates is applied to one of the substrates. In the present embodiment, a sealing material 5 including a 4.5 μm glass microrod is used as the epoxy resin. Next, the TFT array substrate 1 and the counter electrode substrate 2 are overlapped so that the pixels coincide with each other, and the sealing material 5 is cured while applying substantially uniform pressure and heat to the entire surface of the substrate, and the two substrates are bonded. At this time, the extraction electrode 9 formed on the TFT array substrate 1 and the transfer support 6 formed on the counter electrode substrate 2 are connected, and the pair of substrates is also electrically connected. Thereafter, the substrate is cut out to a predetermined size, the liquid crystal 3 is sealed between the substrates, and the liquid crystal display device according to the present embodiment is completed through a predetermined process.

In the present embodiment, when the height of the transfer support 6 is a, the height of the recess 7 is b, and the diameter of the spacer 4, that is, the cell gap value is c, a = 4.6 μm and b =
0.1 μm, c = 4.4 μm, and the height of the transfer column 6 and the concave portion 7 are set so that a−c ≧ b. The cell gap value c is a constant determined at the time of panel design and cannot be changed. On the other hand, the height a of the transfer support 6 and the height b of the concave portion 7 are determined by the cell gap value c, and are values that can be changed to control the panel to have the cell gap value c. When the cell gap is corrected, when a−c ≧ b, the correction can be performed by a method such as reducing the spacer diameter.
In the case of <b, for example, it is necessary to change the thickness of the ITO film layer of the TFT array substrate 1 or the height a of the transfer support 6, and the former is easier to correct. Then, a−c ≧ b. As described above, the height a of the transfer support 6 is formed to be higher than the cell gap value c, while the concave portion having a height equal to or smaller than the difference between the transfer support 6 and the cell gap value is provided at a position corresponding to the position of the transfer support 6. By forming 7, the display quality is less affected by the spacers 4 defining the cell gap and the spacers included in the sealing material 5 and the display quality does not occur due to the gap difference between the spacers 4 and the spacers included in the sealing material 5. , A liquid crystal display device having a high The transfer support 6 in the present embodiment is formed by depositing silver, which is a material of the transfer support, on the counter electrode substrate 2 by a sputtering method and forming a pattern by a photoengraving method. Unlike the columns, they are not affected by the thermocompression bonding conditions, so that the height can be easily controlled, and the yield of products in the panel assembly process is improved.

In this embodiment, the counter electrode substrate 2
Silver was deposited on the outer side of the sealing material 5 by sputtering to form the transfer column 6, but the transfer column 6 was formed.
May be formed on the TFT array substrate 1. Also, the recess 7
May be formed on either of the pair of substrates. Further, the position of the transfer support 6 may be either inside or outside of the sealing material 5, but it is preferable that the outside is less affected by the spacer 4 and the like. Further, as the material of the transfer support 6, a highly conductive material such as gold, platinum, or copper can be used in addition to silver. Further, as a method of forming the transfer column 6, a plasma CVD method or the like may be used instead of the sputtering method. Further, in the present embodiment, the recess 7 having a height of 0.1 μm is formed at a position corresponding to the position of the transfer column 6 by preventing the silicon nitride film 18 a from covering the region of the extraction electrode 9. 7 may be formed by making the thickness of the substrate on which the concave portion 7 is provided or the thickness of any one of the film formation layers on this substrate smaller than other portions.

[0012]

As described above, according to the present invention, a transfer column is provided at a predetermined position in a peripheral portion between a pair of substrates.
When a recess is provided at a position corresponding to one of the transfer posts on a pair of substrates, and the height of the transfer post is a, the height of the recess is b, and the spacer diameter is c, a-
By setting the height of the transfer column and the concave portion so that c ≧ b, the display is less likely to be affected by the spacer and the sealing material that define the cell gap, and the display failure does not occur due to the gap difference between the spacer and the sealing material. A high-quality liquid crystal display device can be obtained.

[0013] Further, the transfer support according to the present invention comprises:
Transfer pillar material is deposited on the substrate by sputtering or CVD, and patterned by photoengraving. The height is controlled because it is not affected by the thermocompression bonding conditions unlike conventional transfer materials. Easy,
Productivity is improved.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view illustrating a structure of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a thin film transistor of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a liquid crystal display device using a conventional general transfer support.

FIG. 5 is a cross-sectional view schematically showing a liquid crystal display device using another conventional transfer support.

[Explanation of symbols]

1 TFT array substrate, 2 counter electrode substrate, 3 liquid crystal,
DESCRIPTION OF SYMBOLS 4 Spacer, 5 sealing material, 6, 6a, 6b transfer support, 7 recess, 8 orientation control film, 9 extraction electrode, 11 transparent insulating substrate, 12 gate electrode, 13
Gate insulating film, 14 semiconductor layers, 15 source electrodes,
16 drain electrode, 17 pixel electrode, 17a ITO
Film, 18 interlayer insulating film, 18a silicon nitride film, 19
Contact hole.

Claims (6)

[Claims] 1. A TFT array substrate having a plurality of thin film transistors and pixel electrodes arranged in a matrix, a common electrode and a color filter, and a counter electrode substrate arranged to face the TFT array substrate at a predetermined distance. A liquid crystal arranged between a pair of substrates, a spacer arranged between the pair of substrates and defining a gap between the pair of substrates, a sealant for bonding the pair of substrates and determining an injection region of the liquid crystal, A transfer post is provided between a concave portion formed on one of the peripheral portions of the pair of substrates and a peripheral portion of the other substrate facing the concave portion and electrically connects the pair of substrates. A liquid crystal display device characterized by the above-mentioned. 2. The height of the transfer column and the concave portion is set so that a−c ≧ b, where a is the height of the transfer column, b is the height of the concave portion, and c is the spacer diameter. The liquid crystal display device according to claim 1, wherein: 3. The liquid crystal display device according to claim 1, wherein the transfer support is made of a material such as gold, silver, platinum, or copper. 4. The transfer post according to claim 1, wherein said transfer post material is deposited on a substrate by a sputtering method, a CVD method, or the like, and is patterned by a photoengraving method. The liquid crystal display device according to claim 1. 5. The liquid crystal display device according to claim 1, wherein the transfer support is provided inside or outside of the sealing material. 6. The concave portion is formed by making the thickness of the substrate on which the concave portion is provided or the thickness of one of the film formation layers on the substrate smaller than other portions. The liquid crystal display device according to claim 1.