JPH0488320A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the reliability of connection and to reduce the outside dimension of the liquid crystal display device by forming a printed circuit into a two-layered structure directly printed with printed wirings on a printed board. CONSTITUTION:The printed circuit 5 is made into the two-layered structure 7 directly printed with the printed wirings 4 on the printed board 3. The printed circuit 5 having such two-layered structure 7 is thin and has excellent bendability and, therefore, the printed circuit can be mounted in a nearly perpendicularly bent state to the liquid crystal display device. Since the window frame width is narrowed in this way, the outside dimension of the liquid crystal display device is reduced and since the printed circuit can be bent without forming a slit to a resin film, the disconnection of the printed wirings by bending is obviated and the connection reliability of the printed circuit is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a liquid crystal display device on which a driving integrated circuit is mounted, and in particular to a dot matrix type liquid crystal display device used in a notebook word processor, a book type personal computer, etc. It is related to.

[Conventional technology]

Conventionally, IC (Integrat) in liquid crystal display devices has been used.
As shown in FIG. 6, the IC chip 22 is mounted by TAB (
This is accomplished by TAB technology, in which the TAB package 25 is connected to the electrode 26a of the liquid crystal display panel 26.

In this TAB packaging, as shown in Figure 7, Kapton (product name) and Upilex (product name)
Most commonly, a three-layer TAB film 27 is used, which has a three-layer structure in which a resin film 23 and a copper foil 24 are bonded together using an adhesive 29.

As shown in FIG. 8, this liquid crystal display device includes a connection between the output terminal side of the TAB package 25 having a top layer structure and an electrode 26a of the liquid crystal display panel 26, and
5 is connected to the printed wiring board 28, and then, as shown in FIG.
is attached to the periphery of the device and assembled.

When this TAB package 25 is mounted as is in a liquid crystal display device, the window frame width B is
It is determined by the size of the B package 25 and the printed wiring board 28, and the window frame width B needs to be about 20 mm. Therefore, in dot matrix type liquid crystal display devices such as notebook type word processors and book type personal computers, which have a large display capacity and a small external size, in order to reduce the external size, a TAB package 25 is used as shown in FIG. A folding method is used in which the device is mounted in a folded state. However, Kapton and Upilex used as resin films each have a thickness of 12
5 μm and 75 μm, and resin films made of these materials are weak against bending and easily break. moreover,
Adhesive 29 shown in FIG. Since the TAB package 25 is used, the thickness of the adhesive side layer increases by 20 to 30 μm, and it is difficult to bend the TAB package 25 as it is. For this reason, for the purpose of improving bendability, the resin film 23 at the bending part has one to three slits 31 formed by consecutively slits 23a as shown in FIG. 10. TAB package 25 with layered TAB film 27
is used. In this case, as shown in Figure 11,
After the TAB package 25, electrode 26a, and printed wiring board 2 are connected, the slit portion 31 is bent so that the printed wiring board 28 is on the back side of the device, as shown in FIG. , then the window frame 30 is attached and assembled.

By using this bending method, the window frame width C is approximately 12
8 mm, compared to when the TAB package 25 shown in FIG. 6 is mounted on a liquid crystal display device as is.
mm, and the external dimensions can be reduced by about 16 mm.

[Problem to be solved by the invention]

However, in the conventional bending method described above, the slit portion 3
Since the mechanical strength of 1... is weakened, the copper foil 24 at the bent portion is likely to break, resulting in a lack of reliability. In addition, since the copper foil 24 at the bent portion is easily broken, the TAB package 25
When mounting a window, it is necessary to increase the number of bending parts and reduce the bending angle, which makes it impossible to fold the window frame compactly, resulting in the problem that the window frame width C becomes wider and the external dimensions cannot be reduced. are doing.

Therefore, an object of the present invention is to provide a liquid crystal display device that can improve connection reliability and reduce external dimensions by narrowing the window frame width C of the liquid crystal display device.

[Means to solve the problem]

In order to solve the above-mentioned problem, the manufacturing method of a liquid crystal display device according to the present invention is provided by a method in which the electrodes of the liquid crystal display panel on the upper periphery of the device and the printed wiring board on the back side of the device are printed with a driving integrated circuit, for example, an IC chip mounted thereon. In a liquid crystal display device connected by a circuit, the following measures are taken.

That is, the printed circuit has a two-layer structure in which printed wiring is directly printed on the printed circuit board, and the connecting surface between the printed circuit and the electrode and the downwardly bent surface with the end of this connecting surface as the bending portion are almost at right angles. On the other hand, the surface including the connection surface between the printed circuit and the printed wiring board is bent at a substantially right angle to the downwardly bent surface so as to be substantially parallel to the back surface of the device.

[For production]

According to the above configuration, the printed circuit has a two-layer structure in which printed wiring is directly printed on the printed circuit board. Since this two-layer printed circuit is thin and has excellent bendability, it can be mounted on a liquid crystal display device with the printed circuit board bent at a nearly right angle. This allows the window frame width to be narrowed, thereby reducing the external dimensions of the liquid crystal display device.

In addition, since the printed circuit with the above-mentioned two-layer structure has excellent bendability, it can be bent without forming slits in the resin film, so the printed wiring will not be disconnected due to bending, and the connection of the printed circuit will be The trajectory improves.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In the liquid crystal display device of this embodiment, as shown in FIG. After being connected to 6a,
A window frame 10 is attached to the periphery of the liquid crystal display device 1 to cover parts of the upper and lower parts and the sides.

As shown in FIG. 2, the TAB packaging described above is performed using a two-layer TAB film 7 having a two-layer structure in which copper foil 4 as a printed wiring is directly printed on a resin film 3 as a printed board. This two-layer TAB film 7 is a tape-shaped two-layer tape made by plating copper on the resin film 3 and molded using a mold, and in this example, a two-layer tape manufactured by Sumitomo 3M Co., Ltd. are using. Further, in this embodiment, Kapton (trade name) having a thickness of 50 μm is used as the resin film 3, and the thickness of the copper foil 4 is 35 μm. Since this copper foil 4 is formed by plating,
The thickness can be set arbitrarily.

In this way, since no adhesive is required and the resin film 3 is also thin, the TAB package 5 using the two-layer TAB film 7 as a whole is sufficiently thin and has good flexibility.

Therefore, as shown in FIG. 1, the TAB package 5 can be bent without forming a bending part such as a slit in the resin film 3, and has sufficient strength against bending. There is.

Connection between the output terminal side of the TAB package 5 and the electrode 6a of the liquid crystal display panel 6 is made using an anisotropic conductive film (not shown). This anisotropic conductive film is in the form of a sheet in which fine metal powders such as nickel and solder balls are dispersed in resin.

By sandwiching this anisotropic conductive film between the output terminal side of the TAB package 5 and the electrode 6a and applying heat and pressure, the TAB package 5 is fixed by the resin, and the TAB package 5 is fixed by the dispersed metal fine powder. Electrical contact is made with the liquid crystal display panel 6.

As this anisotropic conductive film, a semi-hardening type or thermosetting type with high connection reliability is used.

Further, the input terminal side of the TAB package 5 is connected to a printed wiring board 8 by soldering.

A backlight 9 that sends light from below the TAB package 5 is provided below the TAB package 5.

In the above liquid crystal display device, as shown in FIG.
The assembly work from the time the AB package 5 is connected to the electrodes 6a and the printed wiring board 8 until the window frame 10 shown in FIG. 1 is attached will be described below.

First, as shown in FIG. 4, the TAB package 5 is bent vertically downward using the end of the connection surface with the electrode 6a as a bending part. Next, as shown in FIG. 5, the bent TAB package 5 is aligned with the lower surface of the hasycrite 9, that is, parallel to the back surface of the device, with respect to the downwardly bent surface. Fold it at a right angle.

Thereafter, as shown in FIG. 1, the window frame 10 is attached to the periphery of the liquid crystal display device l, and the assembly work is completed.

In this way, in the liquid crystal display device 1 using the TAB package 5 with the two-layer structure, the window frame width A is approximately 10 mm, and compared to the case where the three-layer structure is used as is, the window frame width A is approximately 10 mm. It becomes narrower by 10mm, and its external dimensions are reduced by about 20mm. In addition, compared to the case where the folding method is used with a three-layer structure, the window frame width A is approximately 2 mm narrower, and the external dimension is approximately 4 mm.
It is reduced by mm. Furthermore, since the TAB package 5 can be bent without having a slit, the copper foil 4
The possibility that the connection will be disconnected is extremely small (the connection reliability is high).

〔Effect of the invention〕

As described above, in the method of manufacturing a liquid crystal display device according to the present invention, the printed circuit has a two-layer structure in which printed wiring is directly printed on the printed circuit board, and the connecting surface between the printed circuit and the electrode and the edge of this connecting surface are provided. The downwardly bent surface is approximately at right angles, while the surface including the connection surface between the printed circuit and the printed wiring board is approximately parallel to the back surface of the device. It has a configuration in which it is bent almost at right angles to the plane.

This allows the printed circuit to be bent without forming slits in the printed circuit board. Therefore, the possibility that the printed wiring will be disconnected due to bending is extremely small, and the connection reliability of the printed circuit is improved. Furthermore, since the printed circuit has excellent bendability, it can be mounted on a liquid crystal display device while being bent at a right angle. Therefore, it is possible to narrow the window frame width of the liquid crystal display device, and the external dimensions can be reduced.

[Brief explanation of drawings]

1 to 5 show one embodiment of the present invention. FIG. 1 is a schematic vertical cross-sectional view showing a TAB package mounted on a liquid crystal display device. FIG. 2 is a longitudinal cross-sectional view of a two-layer TAB film. FIG. 3 is a schematic plan view showing a state in which a liquid crystal display panel, a TAB package, and a printed wiring board are connected. FIGS. 4 and 5 are schematic longitudinal sectional views showing one state of the assembly work. 6 and 7 show conventional examples. FIG. 6 is a schematic vertical cross-sectional view showing the state in which the TAB package is mounted on a liquid crystal display device. FIG. 7 is a longitudinal cross-sectional view of a three-layer TAB film. FIG. 8 is a schematic plan view showing a state in which a liquid crystal display panel, a TAB package, and a printed wiring board are connected. FIG. 9 is a schematic vertical sectional view showing a state in which a folding TAB package is mounted on a liquid crystal display device. FIG. 10 is a longitudinal cross-sectional view of a three-layer TAB film with a plurality of slits. Figure 11 shows a liquid crystal display panel, TAB with slits.
FIG. 3 is a schematic plan view showing a state in which a package and a printed wiring board are connected. 1 is a liquid crystal display device, 2 is an IC chip (integrated circuit), 3 is a resin film (printed circuit board), 4 is copper foil (printed wiring), 5
is a TAB package (printed circuit), 6 is a liquid crystal display panel, 7 is a two-layer TAB film, and 8 is a printed wiring board. Figure 1 Patent applicant Sharp Corporation-1'. Figure Figure Figure Figure Figure Figure Figure Figure Figure 0 Wi

Claims (1)

[Claims] 1. In a liquid crystal display device in which the electrodes of the liquid crystal display panel on the upper periphery of the device and the printed wiring board on the back side of the device are connected by a printed circuit equipped with a driving integrated circuit, the printed circuit is It has a two-layer structure in which printed wiring is printed directly on the printed circuit board, and the connecting surface between the printed circuit and the electrode and the downwardly bent surface with the end of this connecting surface as the bending part are almost at right angles. Make sure that the surface including the connection surface with the printed wiring board is almost parallel to the back of the device.
A liquid crystal display device characterized in that it is bent at a substantially right angle to the downwardly bent surface.