JP2002139738A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to attach a COF(chip on film; liquid crystal driving circuit board) to a liquid crystal display panel without folding the COF. SOLUTION: A liquid crystal display element is provided with the liquid crystal display panel 10 wherein a terminal part 14 having a drawer electrode 141 is successively provided on a first transparent electrode substrate 13 side of a display observing surface side and a transparent electrode 151 on a second transparent electrode substrate 15 on a back surface side is connected with a prescribed drawer electrode of the terminal part 14 by a conducting means 111 and the COF 20 having a connection electrode 21 connected face oppositely to the drawer electrode 141 on the end part of one substrate surface 201 side. The COF 20 is attached to the liquid crystal panel 10 so that the one substrate surface 201 side is opposed to the second transparent electrode substrate 15.

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 technique for arranging a liquid crystal drive circuit board on a liquid crystal display panel.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a liquid crystal display panel and its peripheral parts. A main peripheral component is a liquid crystal drive circuit board, one of which is a COF (chip-on-film) in which a liquid crystal drive IC is mounted on a flexible substrate.

FIG. 3 shows a conventional example in which a COF 4 is attached to a liquid crystal display panel 1 which is taken out in two directions.
The liquid crystal display panel 1 includes a display observation surface side transparent electrode substrate 2 called an F plate and a back surface side transparent electrode substrate 3 called an R plate. Terminal portions 2a and 3a are connected to each other.

A liquid crystal driving IC 5 is mounted on the COF 4. In the case of this conventional example, the terminals 2a and 3a are connected to each of the transparent electrode substrates 2 and 3, respectively. The connection electrode portions 4a and 4b are formed in a bifurcated manner.

[0005] The connection of the COF 4 to the liquid crystal display panel 1 is performed by connecting the terminal portion 2a and the connection electrode portion 4a, and connecting the terminal portion 3a.
a and the connection electrode portion 4b are electrically and mechanically joined by, for example, facing each other via an anisotropic conductive film by heat compression. Thereafter, as shown in FIG. 4, the COF 4 is bent to the back side of the back side transparent electrode substrate 3 so as to fit within the size of the liquid crystal display panel 1.

[0006]

In this way, a module having a size of a liquid crystal display panel is assembled. However, this has the following problems.

After the COF 4 is connected to the liquid crystal display panel 1, it is necessary to bend the COF 4, thereby increasing the number of steps. Since the bending angle of the COF 4 is as large as about 180 °, there is a concern that the reliability including the connection portion is reduced.
Since the bent portion of the COF 4 protrudes outside the liquid crystal display panel 1, it hinders miniaturization.

[0008]

This problem is solved by adopting a configuration having the following features. That is, the present invention includes a first transparent electrode substrate on the display observation surface side and a second transparent electrode substrate on the back surface, which are disposed to face each other with the liquid crystal layer interposed therebetween. A liquid crystal display panel in which a portion is connected to the first transparent electrode substrate side, and a transparent electrode of the second transparent electrode substrate is connected to a predetermined lead electrode of the terminal portion by conductive means; A liquid crystal drive circuit board having a connection electrode connected to the extraction electrode in a surface-wise manner at an end on the surface side, wherein the liquid crystal drive circuit board has the one substrate surface side on the second transparent electrode The liquid crystal display panel is attached to the liquid crystal display panel so as to face the substrate.

According to this configuration, it is only necessary to place the liquid crystal drive circuit board on the second transparent electrode substrate on the back side and connect the connection electrode to the lead electrode of the terminal portion.し な い No need to bend. Therefore, the number of steps is reduced, and there is no fear that the reliability is reduced.

In the present invention, the liquid crystal driving circuit board is preferably a flexible substrate on which a liquid crystal driving IC is mounted and which is smaller in area than the liquid crystal display panel.
According to this, further miniaturization can be achieved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded cross-sectional view.
0, and a COF 20 as a liquid crystal drive circuit board.

The liquid crystal display panel 10 includes a peripheral sealing material 11.
The first transparent electrode substrate (F
Board 13, and a second transparent electrode substrate (R board) 15 on the back side, and each of the substrates 13, 15 surrounded by the peripheral sealing material 11.
Inside, a liquid crystal layer 17 is sealed.

Transparent electrodes (display electrodes) 131 and 151 made of ITO (indium tin oxide) are formed on the inner surfaces of the first and second transparent electrode substrates 13 and 15, respectively. The electrode substrate 13 includes the second transparent electrode substrate 1
Terminal portions 14 formed to be larger than 5 are continuously provided.

In this case, as shown in the bottom view of FIG. 2, the terminal portion 14 has an extraction electrode 141 connected to the transparent electrode 131 of the first transparent electrode substrate 13 and a second transparent electrode substrate 15 side. An extraction electrode 142 for the transparent electrode 151 is formed. In this embodiment, the transparent electrode 151 on the second transparent electrode substrate 15 side is provided via the transfer material 111 included in the peripheral sealing material 11. Extraction electrode 1
42. Note that, instead of the transfer material 111, for example, a conductive rubber connector may be used.

In this embodiment, the COF 20 is made of a double-sided flexible substrate, and connection electrodes 21 and 22 corresponding to the extraction electrodes 141 and 142 are formed at one end of one substrate surface 201. A liquid crystal driving IC 23 is mounted on a predetermined portion of the other substrate surface 202 of the COF 20. In order to reduce the size of the liquid crystal display element, the COF 20 is preferably smaller in area than the liquid crystal display panel 10.

The COF 20 is disposed on the second transparent electrode substrate 15 such that one of the substrate surfaces 201 faces the second transparent electrode substrate 15 on the back side, and the connection electrode 21 and the extraction electrode 141 are connected to each other. The connection electrode 22 and the extraction electrode 14
2 are arranged in a plane facing each other via, for example, an anisotropic conductive film, and are joined by heat compression.

The flexible substrate of the COF 20 is
The circuit may be formed only on one side thereof. In this case, the liquid crystal driving IC 23 includes the connection electrodes 21 and
The second transparent electrode substrate 15 is mounted on the one substrate surface 201 side on which the substrate 22 is formed and faces the second transparent electrode substrate 15 on the rear surface side.

[0018]

As described above, according to the present invention,
Since it is not necessary to bend the COF (liquid crystal drive circuit board), the process can be simplified, and the reliability of the board including the connection portion is improved. Also, since there is no bent part, CO
The size of the F itself and the size of the liquid crystal display element can be reduced. Further, the cost can be reduced as a whole.

[Brief description of the drawings]

FIG. 1 is an exploded sectional view showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a bottom view of the embodiment.

FIG. 3 is a plan view schematically showing a conventional example.

FIG. 4 is a side view of the conventional example.

[Explanation of symbols]

 Reference Signs List 10 liquid crystal display panel 11 peripheral sealing material 111 transfer material 13 first transparent electrode substrate (display observation surface side) 131 transparent electrode 14 terminal portion 141, 142 extraction electrode 15 second transparent electrode substrate (back surface side) 151 transparent electrode 20 COF ( Liquid crystal drive circuit board) 201 one substrate surface 202 the other substrate surface 21, 22 connection electrode 23 liquid crystal drive IC

Continuation of front page (72) Inventor Katsuya Miyoshi 91, Yotanuki-cho, Miyoshi-shi, Hiroshima F-term in Hiroshima Opto Co., Ltd. (Reference) 2H092 GA50 GA59 GA60 NA27 PA06 5G435 AA00 AA18 BB12 EE33 EE36 EE40 EE42 GG21

Claims (2)

[Claims] 1. A terminal portion including a first transparent electrode substrate on a display observation surface side and a second transparent electrode substrate on a rear surface side opposed to each other with a liquid crystal layer interposed therebetween, and having a lead electrode of each of the transparent electrode substrates. Are connected to the first transparent electrode substrate side, and a liquid crystal display panel in which the transparent electrode of the second transparent electrode substrate is connected to a predetermined lead electrode of the terminal portion by conductive means; A liquid crystal drive circuit board having a connection electrode connected to the extraction electrode in a surface-wise manner at an end of the liquid crystal drive circuit board, the liquid crystal drive circuit board having the one substrate surface side facing the second transparent electrode substrate A liquid crystal display element, which is attached to the liquid crystal display panel so as to face the liquid crystal display panel. 2. The liquid crystal driving circuit board according to claim 1, wherein the liquid crystal driving circuit board is a liquid crystal driving IC.
The liquid crystal display element according to claim 1, wherein the liquid crystal display element is formed of a flexible substrate smaller in area than the liquid crystal display panel.