JP2002107734A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spacer structure which reduces the filling time required for filling a liquid crystal composition into a liquid crystal cell and bubbles or the like which may occur at the time of filling. SOLUTION: In a liquid crystal cell 1, a liquid crystal composition 50 is held between two substrates 10 and 100 which face each other with a prescribed gap between them, and two substrates are brought into close contact with each other by a seal material 32 except a liquid crystal filling port 33 formed on an arbitrary side. One substrate is provided with spacers 31 which are used to keep the distance between the substrates. A condition of a/b<=1.5, where (a) is the orthogonal projection length to the side having the liquid crystal filling port and b is the orthogonal projection length to the side orthogonal to (a), is given to the spacer 31 for which the distance from a segment 32a connecting one end and the other of the seal material 32 is the shortest.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, light-weight, small-sized, and high-definition liquid crystal display devices have been developed in the field of information equipment mainly for computers and the field of video equipment mainly for televisions.

At present, most of the liquid crystal cells generally used are composed of two glass substrates having electrodes and a liquid crystal layer sandwiched between them.

For example, in a color active matrix type liquid crystal display device, a thin film transistor using amorphous silicon or polysilicon as a semiconductor layer on an array substrate as a first substrate, a pixel electrode connected to the thin film transistor, a scanning line, and A signal line is provided, and a color filter layer, which is a coloring layer corresponding to three primary colors of light, and a counter electrode are formed on the counter substrate, which is the second substrate. A spacer is provided between the two substrates to keep the distance between the two substrates constant. The two substrates are fixed with an adhesive disposed on the peripheral edge of the substrate.

On the other hand, in recent years, in order to reduce the accuracy required when two substrates are bonded, a peripheral light-shielding layer is formed on an array substrate, or light leakage caused by a spacer provided in a display area is reduced. In order to prevent this, a method of patterning and forming a spacer on an array substrate has been used.

[0006]

In the above-described method and structure for forming a liquid crystal cell, depending on the shape of the spacer, the injection time for injecting the liquid crystal composition into the liquid crystal cell increases, and the production capacity decreases. Problems arise. Also,
Depending on the size and shape of the spacer, there is a problem that bubbles are generated when the liquid crystal composition is injected into the liquid crystal cell.

An object of the present invention is to provide a spacer structure capable of reducing an injection time for injecting a liquid crystal composition into a liquid crystal cell and reducing bubbles and the like which may be generated during the injection in order to solve the above-mentioned problems. Things.

[0008]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned problems, and has a liquid crystal display device in which a liquid crystal composition is sandwiched between two substrates opposed at a predetermined interval. In the two substrates, a spacer having a function of maintaining a constant distance between the two substrates is formed on at least one of the substrates, and one end of a sealing material for sealing the two substrates among the spacers and the other end. The spacer having the shortest distance from the line connecting the liquid crystal composition has an orthogonal projection length "a" in the direction of the liquid crystal injection port into which the liquid crystal composition is injected, and has a positive projection length in the direction orthogonal to the direction of the liquid crystal injection port. An object of the present invention is to provide a liquid crystal display device, wherein a relationship of “a / b ≦ 1.5” is given when a projection length is “b”.

[0009]

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

Embodiment 1 FIGS. 1 and 2 are schematic views illustrating a liquid crystal cell of a liquid crystal display device according to an embodiment of the present invention. 1 shows a state in which the liquid crystal cell is viewed from the direction of the display surface. FIG. 2 shows a state in which one pixel of the liquid crystal cell shown in FIG. 1 is extracted. Is shown.

The liquid crystal cell 1 shown in FIG. 1 and FIG.
The array substrate 10 as a second substrate and the opposing substrate 100 as a second substrate are separated from each other by a plurality of spacers 31.
It is bonded by a seal material 32 facing 0 at a predetermined interval. The array substrate 10 includes thin film transistors (TFT) and R (red), G (green), and B
(Blue) three color filter layers are provided. The opposing substrate 100 is made of indium-tin oxide (Indi-tin oxide) disposed on a glass substrate 101 which is a transparent insulating substrate.
um Tin Oxide (hereinafter referred to as ITO)) and a counter electrode 102 formed of a transparent member such as
2 is provided.

The array substrate 10 has a glass substrate 11 which is a transparent insulating substrate as described in detail in FIG. 2, and an undercoat layer 12 having a predetermined thickness is formed on the glass substrate 11. Is formed.

On the undercoat layer 12, a semiconductor layer 13 which is a polycrystalline silicon (polysilicon, hereinafter referred to as p-Si) film having a predetermined thickness, and a gate insulating film 14 covering the semiconductor layer 13 are formed. Have been. On the gate insulating film 14, a gate electrode 15 and an interlayer insulating film 16 are deposited.

On both sides of the channel region of the semiconductor layer 13,
A group V element is implanted at a predetermined dose, and an interlayer insulating film 1 is formed.
The source electrode 17 and the drain electrode 18 are connected through the through holes 6. Note that the semiconductor layer 13, the gate insulating film 14, the gate line 15, the interlayer insulating film 16, the source electrode 17 and the drain electrode 18 constitute a TFT.

The semiconductor layer 13, the gate insulating film 14,
The gate line 15, the interlayer insulating film 16, the source electrode 17, and the drain electrode 18 are covered with a passivation film 19, and further, for each pixel region, three colors of red (R), green (G), and blue (B). Are respectively covered with the color filter layers 20R, 20G or 20B. At a predetermined position on each of the color filter layers 20R, 20G and 20B, a pixel electrode 21 made of, for example, ITO is formed. The pixel electrode 21 is covered with the alignment film 22.

Next, a method of manufacturing the liquid crystal cell shown in FIGS. 1 and 2 will be described.

First, the glass substrate 11 of the array substrate 10
An undercoat layer 12 made of silicon nitride and silicon oxide is formed on one surface of the substrate by a plasma CVD method.

Next, an amorphous silicon layer (hereinafter referred to as an a-Si layer) is deposited on the undercoat layer 12 to a predetermined thickness by, for example, a plasma CVD method.

Subsequently, annealing is performed at a predetermined temperature and for a predetermined time in a nitrogen atmosphere to reduce the hydrogen concentration in the a-Si film, and then laser annealing is performed to form a p-Si film and pattern the semiconductor. The layer 13 is formed.

Next, a gate insulating film 14 is deposited by a plasma CVD method, and a Mo film or Mo having a thickness of about 0.3 μm is formed on the gate insulating film 14 by a sputtering method.
A -W film is deposited and patterned to form a gate electrode 15 and a scanning line (not shown).

Next, P (phosphorus) is implanted into the semiconductor layer 13 at a predetermined dose using the gate electrode 15 as a mask.

Subsequently, an interlayer insulating film 16 is formed and patterned into a predetermined shape to form a through hole.
Is deposited and patterned into a predetermined shape to form a signal line (not shown), a source electrode 17 and a drain electrode 18.

In this manner, the semiconductor layer 13, the gate insulating film 14, the gate electrode 15, the interlayer insulating film 16, the source electrode 17, and the drain electrode 18, which are sequentially deposited, are nitrided by the plasma CVD method. A passivation film 19 made of silicon is formed.

Next, in order to form three color filter layers of red (R), green (G) and blue (B) for each pixel area, a red pigment is dispersed in a predetermined order. Let R
A photosensitive resist is applied, exposed to a predetermined shape, developed, and baked at a predetermined temperature to form a through-hole 21.
The color filter layer 20R having a is formed. At this time, a pattern for the spacer 31 is also formed on the gate electrode 15 at the same time.

Subsequently, for example, G in which a green pigment is dispersed
For the color filter layer 20R
The color filter layer 20 </ b> G is formed in the same process as described above.
At this time, a pattern for the spacer 31 is simultaneously formed on the red pattern laminated on the gate electrode 15.

Further, a photosensitive resist for B in which a blue pigment is dispersed is applied, and a color filter layer 20B is formed in the same process as the color filter layer 20R. At this time, a pattern for the spacer 31 is simultaneously formed on the red and green patterns stacked on the gate electrode 15.

Accordingly, the individual color filter layers 20R,
The red, green, and blue patterns formed simultaneously with 20G and 20B are stacked on the gate electrode 15 to function as spacers 31 that keep the distance between the counter substrate 100 and the array substrate 10 constant. A height is provided, whereby a spacer 31 is obtained. The spacer 31 may be provided, for example, at the boundary between the color filter layers 20R, 20G, and 20B. Spacer 3
Reference numeral 1 denotes a step of forming a light-shielding layer (not shown) that covers a peripheral portion of the display area. In this case, the spacer 31 or the light shielding layer is formed of a black resin.

Next, ITO is deposited to a predetermined thickness by sputtering and patterned into a predetermined shape.
The pixel electrode 21 is formed. At this time, a part of the pixel electrode 21 is in contact with the drain electrode 18 below the color filter layer through the through hole 21a.

Next, each color filter layer 20R, 20G
An alignment film material made of, for example, polyimide is applied on the pixel electrodes 20B and the pixel electrode 21, and an alignment process is performed to form an alignment film 22.

On the other hand, in the counter substrate 100, after an undercoat layer (not shown) is provided on a glass substrate 101, which is a transparent insulating substrate, a counter electrode 102 of a transparent member made of ITO or the like is formed. For example, an alignment film 103 made of polyimide is provided.

Next, a sealing material 3 is provided around the array substrate 10.
2 is applied except for the liquid crystal injection port 33, and the opposite substrate 100
By bonding, an empty cell is created.

Thereafter, the liquid crystal composition 50 is injected into the empty cell from the liquid crystal injection port 33, and the liquid crystal injection port 33 is sealed with a sealing material (not shown), whereby the liquid crystal cell 1 is obtained.

As shown in FIG. 3, the spacer 31 has a substantially rectangular shape when viewed from the plane, and has, for example, a direction parallel to the direction in which the liquid crystal injection port 33 of the empty cell is provided and the liquid crystal injection port 33. It is assumed that each side is directed parallel to each of the directions orthogonal to the direction in which is provided.

Regarding the spacer 31 as shown in FIG.
Of each side of the spacer 31, the orthogonal projection length in the direction of the liquid crystal injection port 33 is "a", and the orthogonal projection length in the direction orthogonal to the side of the liquid crystal injection port 33 is "b". “A / b”, which is the ratio of the lengths of the sides, is formed under the conditions A to F in Table 1 below,

[Table 1]

When the injection time required to inject the liquid crystal composition 50 from the liquid crystal injection port 33 into the empty cell was measured, the injection time was significantly increased in the example of "E" as shown in FIG. Was observed. Note that the direction in which the liquid crystal injection port 33 exists is a direction described in a direction perpendicular to a line 32 a connecting one end of the sealing material 32 and the other end.

Therefore, "a / b = 1.5" shown by "D"
When “a / b” is larger than “6”, the spacer 31
It can be determined that the ratio of the lengths of the sides is not appropriate. From this, in the spacer 31, the ratio of the length of each side “a /
b ”needs to be set to be smaller than about 1.56. More preferably,“ a / b ”is“ a / b ≦ 1.
5 ”is desired.

The spacer which must maintain the shape obtained in this manner, that is, the relationship of the ratio of the lengths of each side “a / b” is used when the liquid crystal composition 50 is injected. The spacer closest to 33, that is, the spacer having the shortest distance from a line segment 32a connecting one end of the sealing material 32 and the other end, as shown in FIG.

A polarizing plate (not shown) is attached to the outer surface of each of the array substrate 10 and the counter substrate 100 of the liquid crystal cell 1 thus formed, assembled into a liquid crystal module, and a driving circuit (not shown) is attached to the color plate. When the image was displayed, a display with high contrast was obtained.

Embodiment 2 In Embodiment 1 described above, an example in which the present invention is applied to a liquid crystal display device provided with a color filter layer on an array substrate has been described. It may be arranged on the counter substrate side.

An example in which a color filter layer is provided on the counter substrate side will be described with reference to FIG. Note that the same configuration as that of the first embodiment described above is denoted by the reference numeral obtained by adding 200, and the detailed description is omitted. Moreover, since the state viewed from the display surface is similar to FIG. 1, only the cross section is shown.

As shown in FIG. 5, a predetermined distance is maintained between the array substrate 210 and the opposing substrate 290 of the liquid crystal cell 201 by a spacer described below.
The liquid crystal composition 50 has been injected.

The array substrate 210 includes an undercoat layer 212 formed on one surface of a glass substrate 211 which is a transparent insulating substrate, a semiconductor layer 213 which is a p-Si film, a gate insulating film 214, a gate electrode 215, Interlayer insulating film 21
6, source electrode 217, drain electrode 218, passivation film 219, pixel electrode 221 and alignment film 222
have.

It should be noted that the pixel electrode 221 has a through hole 221 formed at a predetermined position of the passivation film 219.
Through a, it is connected to the drain electrode 218.

The opposing substrate 290 has a color filter layer 292R of three colors of red (R), green (G), and blue (B) for each pixel region disposed on a glass substrate 291 which is a transparent insulating substrate. , 292G, and 292B, and a counter electrode 29 made of a transparent member such as ITO laminated on the respective color filter layers 292R, 292G, and 292B.
3 and an alignment film 294 that covers the counter electrode 293.

At a predetermined position of the color filter layer 292R, a green pattern and a blue pattern are sequentially laminated.
It functions as a spacer 295 for maintaining a space between the array substrate 210 and the array substrate 210.

[Comparative Example] Under the same conditions as in Example 2, spacers were formed under the conditions of M to O in Table 2 below, and the injection time required for injection of the liquid crystal composition was determined.

[0047]

[Table 2]

However, in the case of M and N, the liquid crystal composition 50 could be injected properly.
It has been confirmed that 0 is not properly filled in the liquid crystal cell and bubbles remain. As described above, the lower limit of the length ratio “a / b” of each side of the spacer is 2.5 × 10 ^−4.
It is.

[0049]

As explained above, according to the present invention,
When defining the shape of the spacer provided in the display area of the liquid crystal cell, regarding the two sides of the spacer, the length of the orthogonal projection to the side on the liquid crystal injection port side and the orthogonal projection to the direction perpendicular to the two sides are set as follows. By making the length 5 times or less, the injection time for injecting the liquid crystal composition into an empty cell can be shortened, and the production capacity is improved.

When a spacer is formed using a resin, the spacer can be selectively formed in a non-display area. Therefore, in the display area, light leakage that may occur around the spacer can be prevented, and a display with high contrast can be achieved. Can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view of a liquid crystal cell to which an embodiment of the present invention is applied, viewed from a display surface direction.

FIG. 2 is an enlarged sectional view of one pixel of the liquid crystal cell shown in FIG.

FIG. 3 is a schematic diagram illustrating characteristics of a shape of a spacer of the liquid crystal cell shown in FIGS. 1 and 2;

4 is a graph illustrating the relationship between the shape of the spacer shown in FIG. 3 and the injection time of a liquid crystal composition into a liquid crystal cell.

FIG. 5 is an enlarged cross-sectional view of one pixel of a liquid crystal cell different from the embodiment shown in FIGS. 1 and 2;

[Explanation of symbols]

 1,201 ... liquid crystal cell, 10, 210 ... array substrate, 20R, 292R ... color filter layer (R), 20G, 292G ... color filter layer (G), 20B, 292B ... Color filter layer (B), 31, 295: spacer, 32: sealing material, 33: liquid crystal injection port, 50: liquid crystal composition, 100, 290: counter substrate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Yamamoto 1-9-2, Hara-cho, Fukaya-shi, Saitama Prefecture Inside the Toshiba Fukaya Plant Co., Ltd. No. 2 F-term in Toshiba Fukaya Plant (reference) 2H089 LA09 LA10 LA11 LA12 LA13 LA18 LA19 LA20 MA03X NA08 NA14 PA09 QA16 TA09 TA12 5C094 AA43 BA03 BA43 CA19 CA24 DA13 EA04 EA05 EA07 EB02 EC03 ED03 GB10

Claims (4)

[Claims] 1. A liquid crystal display device in which a liquid crystal composition is sandwiched between two substrates opposed to each other at a predetermined interval, wherein the two substrates have a constant distance between at least one of the substrates. A liquid crystal composition is injected into a spacer having a shortest distance from a line connecting one end of the sealing material for sealing the two substrates and another end of the spacer among the spacers. When the orthographic length in a direction of the liquid crystal injection port is "a" and the orthographic length in a direction orthogonal to the direction of the liquid crystal injection port is "b", "a"
/B≦1.5 ”. 2. The liquid crystal display device according to claim 1, wherein the spacer is formed by laminating a color filter layer provided on the at least one substrate. 3. The liquid crystal display device according to claim 1, wherein the spacer is provided on a substrate including a thin film transistor among the two substrates. 4. The liquid crystal display device according to claim 1, wherein the spacer is provided on a substrate including a counter electrode of the two substrates.