JPH04147223A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To decrease the pitch between the electrodes led out of a liquid crystal panel and to improve the resolution by varying the group leading out quantity of the adjacent electrodes and superposing a part of adjacent films on each other. CONSTITUTION:The electrode group 4a of the group G1 varying the leading out quantity of the electrodes 4 led out of the effective display part 3 of the liquid cristal panel 1 is connected to the connecting part 7a of the 1st film 5a and the electrode group 4b of the other group G2 is connected to the connecting part 7b of the 2nd film 5b and is connected to a driving circuit element 2. The constitution in which the films are partly superposed on each other is adopted. The width b of the electrode groups 4a, 4b led out of the effective part 3 is made smaller than the effective width a of the connecting parts 7a, 7b according to this constitution and the pitch PLC between the respective electrodes is narrowed. The short-circuit phenomenon between the adjacent electrodes 9 is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device, and particularly to a connection structure between electrodes led out from a liquid crystal panel and a drive circuit element (IC).

[Summary of the invention]

The present invention provides a liquid crystal display in which a drive circuit element is installed on a film that is fixed in contact with a liquid crystal panel, and a large number of electrodes led out from the liquid crystal panel are connected to the drive circuit element via a terminal pattern on the film. In the display device, among the large number of electrodes, each group includes a number of electrodes corresponding to the number of terminals of the terminal pattern, and the large number of electrodes are grouped, and the amount of output of the adjacent groups is different, By overlapping parts of the films adjacent to each other, it is possible to narrow the pitch between the electrodes led out from the liquid crystal panel, thereby improving the resolution.

2. Prior Art] Generally, in a liquid crystal display device, the shape of a portion of the liquid crystal panel to which an external drive circuit element (NC) is connected is a major factor determining the resolution of the liquid crystal display device.

The typical connection structure for high resolution liquid crystal display devices with external drive circuit elements is C0F (Chip on
film) and COG (Chip on gla
ss).

As shown in FIG. 4, in the COF, a drive circuit element (22) is installed on a film (21), and the connection between the liquid crystal panel panel 23) and the drive circuit element (22) is made on the film (21). ) The terminal pattern (24) formed on the liquid crystal panel (23) and the electrode (25) led out from the liquid crystal panel (23) are fixed in contact with each other using an anisotropic conductive adhesive or the like (26). still,(
27) is a bump, and (28) is a circuit board.

COG is the film (21) as shown in FIG.
Directly connect the connection terminal (
29) and an electrode (23) derived from the liquid crystal panel (23).
25) and are fixed in contact with each other.

As shown in FIG. 6, the conventional connection structure in COF is to group a large number of electrodes (25) derived from the effective display area (30) of the liquid crystal panel (23) into units of 100 to 160 pins, and Group electrode group (25a)
drive circuit element (22) installed on the film (21)
Electrical connection is made via the terminal pattern (24) on the film (21).

[Problem to be solved by the invention]

However, in the conventional connection structure in COF, the film (21) on which the drive circuit element (22) is installed
) and the liquid crystal panel (23) are arranged horizontally in a row, the width m of the invalid area between adjacent films (21) increases, and accordingly, the connection for one group increases. It became necessary to design the distance between the effective width a of the portion (31) and the width of the electrode group (25a) derived from the effective display section (30) so that a<b, and as a result, the distance between each electrode (32) There is a problem in that the pitch p cannot be narrowed and high resolution cannot be obtained.

Therefore, in the past, in order to obtain high resolution, the electrodes (32) are led out alternately and the connection parts are arranged in two rows, one on the outside (31a) and one on the inside (31b), as shown in FIG. There is also a method, but the inner connection part (31b)
There is a risk that adjacent electrodes (32) may be short-circuited, which is not preferable in terms of reliability.

The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal display device in which the pitch between electrodes led out from a liquid crystal panel can be narrowed, and the resolution can be improved. It is about providing.

Means for Solving the Problems] The present invention provides a drive circuit element (2) installed on a film (5) that is fixed in contact with a liquid crystal panel (1).
A large number of electrodes (4) derived from 1) are connected to a drive circuit element (
In the liquid crystal display device (A) which is connected to 2) via the terminal pattern (6) on the film (5), among the many electrodes (4), the terminal pattern (6) on the film (5)
The number of electrodes corresponding to the number of terminals in each group is
The large number of electrodes (4) are grouped, the amounts of output of the adjacent groups (G1) and (G2) are different, and parts of the adjacent films (5) are overlapped.

[Effect]

According to the above-described configuration of the present invention, the electrode groups (4a), (4b) are drawn out from the effective display portion (3) more than the effective width a of the connection portions (7a), (7b) for one group.
This makes it possible to reduce the width of each electrode (9
) can narrow the pitch PTC between adjacent electrodes (9), and can also prevent short-circuiting between adjacent electrodes (9).
It is possible to improve resolution and reliability.

Pretext Flow Side] Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 3.

FIG. 1 is a plan view of the main parts of the liquid crystal display device (A) according to this embodiment, particularly showing the connection structure between the liquid crystal panel (1) and the drive circuit element (2).

The above connection structure of this liquid crystal display device (A) connects a large number of electrodes (4) led out from the effective display area (3) of the liquid crystal panel (1) in units of 100 to 160 pins, that is, a film (5). Group in units of number corresponding to the number of terminals in the terminal pattern (6) above, and one group (G1)
The electrode group (4a) is connected to the first film (5a) on which the drive circuit element (2) is installed at the first connection part (7a) and a different electrode group containing conductive particles with a particle size of 5 to 30 μm, for example. The electrode group (4b) related to the other group (G2) is connected via a directional conductive adhesive or the like to the second film on which the drive circuit element (2) is installed at the second connection part (7b). Similar to (5o), they are connected via an anisotropic groove N adhesive, etc., and one electrode group (4a) is connected to the drive circuit element via the terminal pattern (6) on the first film (5a). (2] and is electrically connected to the other electrode 1 (
4b) is the terminal pattern (
6) is electrically connected to the drive circuit element (2).

The first connecting portion (7a) is located inward than the second connecting portion (7b), that is, on the effective display portion (3) side, and
A part of the film (5a) and a part of the second film (5b) are overlapped, so that a part of the second connection part (5b) exists under a part of the first film (5a). It is said that

Then, the electrode group (4b
) is formed by the central part, that is, the first
The first connecting portion (7a) and the electrode group (4d) are configured to be constricted at a portion (8) that is an extension of the connecting portion (7a), so that the first connecting portion (7a) and the electrode group (4d) do not come into contact with each other.

According to this configuration, it is possible to make the width of the electrode group (4a) led out from the effective display section (3) smaller than the effective width a of the first connection portion (7a) for one group, for example.

Here, the pitch between the electrodes (9) of each group in the effective display B (3) of the liquid crystal panel (1) is PTC, and each terminal (10
) is the pitch between Pc, the number of terminals is n, and the other group (
The pitch between each electrode (9) at the constriction part (8) of the electrode group pattern in G2) is PX, and the margin between the groups, that is, the width C of the invalid part (11) on the film (5), is the terminal (
10) When the number of pitches corresponding to the pitch PC between 10) and 10) is K, the following relational expression holds true.

Pc 2 (1-/n) ・PLCPX= 0
...=(1) At this time, P c < P LC, I!
D: The pitch Pc between the terminals (10) on the film (5) is greater than the pitch PLC between the electrodes (9) of the effective display area (3).
is small, if there is a margin between groups, that is, if high resolution is not considered, the conventional connection structure (see Figure 6) is used.
becomes the same as

Conversely, P, ≧PLC1, that is, the electrode (9) of the effective display area (3)
) PLC pitch between terminals (10) on film (5)
When the pitch is smaller than the pitch Pc between the two, the connection structure of this embodiment is effective and high resolution is possible.

In the above parameters, the number of terminals n is usually 80°10
0 and 160 terminals currently exist, and the margin between the groups is to facilitate the alignment of the connection between the liquid crystal panel (1) and the film (5), and the electrodes (9) at both ends of the film (5). ) and to increase the adhesive strength at each connection part (7a), (7b). Also,
The pitch P between the electrodes (9) in the constricted portion (8) is determined by the trade-off between the fineness of the pattern and the resistance value, since the electrodes serve as a wiring section for routing. In this example,
The electrode is coated with N1 plating or the like to lower the resistance value.

Here, by keeping the above parameters K and n constant, P
c and P. FIG. 2 shows an example in which PLO is calculated based on the above equation (1) by changing the numerical values of .

At present, in practical terms, the terminal (
10) The pitch Pc between the electrodes has a tentative limit of 100 μm, and the fine pattern pitch (corresponding to P in this example) between the electrodes has a tentative limit of 40 μm. On the other hand, the resolution of a normal liquid crystal display device, that is, the effective display area (3)
The pitch PLC between the electrodes (9) in is 110 μm, and if the connection structure of this example is used, as shown in ■ in FIG. 2, P c = 150 μm, Px-63, 1 μ
m can be connected easily at present.

Also, as shown in ■ in Figure 2, P, = 100 μm, P
, = 40 μm, which is the current limit value, the resolution of the liquid crystal display device, that is, the electrode (
9) The pitch between PLCs can be made as fine as about 70 μm.

By the way, in the first connection part (7a), the first
When contacting and fixing the film (5a) on the liquid crystal panel (1), the adhesive may flow laterally and enter the constricted part (8) of the electrode group in the other group (G2) (as shown by the two-dot chain line). ). In this case, since the pitch PH1 between the electrodes (9) in the constriction part (8) is very narrow, the adhesive that has entered the adhesive, especially the conductive particles with a particle size of 5 to 30 μm contained in the adhesive, may be interposed between the adjacent electrodes. There is a risk that the electrodes (9) that are connected to each other may be short-circuited.

Therefore, in this example, the pitch Px of the opening of the electrodes (9) in the constriction part (8) is not constant, but the pitch in the central part is set close.
By setting the pitch of the outer portion sparsely, the above-mentioned short circuit phenomenon is prevented.

As described above, according to this example, the electrode groups (4a), (4b) are drawn out from the effective display portion (3) by the effective width a of the connection portions (7a), (7b) for each group.
It becomes possible to reduce the width of the effective display B (
The pitch PLO between the electrodes [9] in 3) is the pitch P between the terminals (10) on the film (5). can be made smaller than. As a result, it is possible to promote the narrowing of the pitch PLC between the electrodes (9) of the effective display B (3), and it is possible to realize a high resolution of the liquid crystal display device.

In addition, with the expansion of the effective width a of the connection parts (7a) and (7b), the pitch between the electrodes (9) of the connection parts (7a) and (7b), especially on the anisotropic conductive adhesive, has been widened. If this can be done, short-circuiting between adjacent electrodes (9) in the adhesive will not occur, and the reliability of the liquid crystal display device (A) can be improved.

[Effects of the invention:- According to the liquid crystal display device according to the present invention, the pitch between the electrodes led out from the liquid crystal panel can be narrowed, and the resolution of the device itself can be increased.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view of the main parts of the connection structure of the liquid crystal display device according to this embodiment, FIG. 2 is a table showing a calculation example according to this embodiment, and FIG. FIG. 4 is a configuration diagram showing a COF, FIG. 5 is a configuration diagram showing a COG, and FIG. 6 is a connection structure of a liquid crystal display device according to a conventional example. FIG. 7 is a partially cutaway plan view of the main parts, and FIG. 7 is an enlarged view of the main parts showing another conventional example. (A) is a liquid crystal display device, (1) is a liquid crystal panel, (2) is a drive circuit element, (3) is an effective display area, (5) is a film, (6) is a terminal pattern, and (7) is a connection part. , (8) is the constriction, (9) is the electrode, and (10) is the terminal. Agent Hide Matsukuma Seigome Night Crystal Display Bush 1

Claims (1)

[Claims] A drive circuit element is installed on a film that is fixed in contact with a liquid crystal panel, and a large number of electrodes led out from the liquid crystal panel are connected to the drive circuit element via a terminal pattern on the film. In the liquid crystal display device, among the large number of electrodes, the number of electrodes corresponding to the number of terminals of the terminal pattern is set as one group, and the large number of electrodes are grouped, and the lead-out amount of each adjacent group is different. A liquid crystal display device in which adjacent portions of the above-mentioned films are stacked on top of each other.