JPH05183247A - Flexible printed board and liquid crystal display - Google Patents

Abstract

PURPOSE:To improve the reliability of connection of an FPC and to provide a highly reliable liquid crystal display. CONSTITUTION:At least one dummy terminal 5, which does not participate in electrical connection, is provided at each of both end parts on the outside of a group of effective connection terminals 4 connected to a base film 3 of an FPC. In such a way, the dummy terminals 5 are respectively provided at both end parts on the outside of the group of the connection terminals of the FPC, whereby the generation of disconnection due to a stress or the like at both end parts on the outside is prevented and a display having a high reliability of connection is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly applicable to high density, multi-terminal L
The present invention relates to a flexible printed circuit board (hereinafter abbreviated as FPC) used for mounting a CD panel and the like and a liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, a connection terminal group of an FPC has been formed opposite to a terminal lead-out portion for connection with an external circuit of a liquid crystal panel for electrical connection.

[0003]

In the conventional FPC, all terminals are used as effective connection terminals. Therefore, when a stress is generated due to a difference in thermal expansion coefficient between the FPC base film and the glass substrate, for example, There was a drawback that the connection terminal was broken and immediately caused a defect. Therefore, an object of the present invention is to prevent disconnection due to stress or the like and obtain an FPC and a liquid crystal display device with high connection reliability.

[0004]

The FPC of the present invention is characterized in that reinforcing members which are not involved in electrical connection are arranged at both outer ends of the connection terminal group.

In the liquid crystal display device of the present invention, a group of connection terminals of the FPC and a terminal lead-out portion for connecting the reinforcing member and an external circuit of the liquid crystal panel are electrically connected through an anisotropic conductive film. It is characterized by

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.
It is viewed from the PC base film side, and FIG. 2 is a sectional view thereof. Reference numeral 1 is a liquid crystal panel terminal lead-out portion, 2 is an anisotropic conductive film, 3 is a base film, 4 is an effective connection terminal, and 5 is a dummy terminal.

When the dummy terminals 5 are provided in this way, even if shear stress is generated due to a difference in thermal expansion coefficient between the base film 3 and the liquid crystal panel terminal take-out portion, a load is applied to the outermost dummy terminals 5. No load is applied to the inner effective connection terminal 4. In addition, since the dummy terminal, which is the reinforcing member, is made of the same material as the effective connection terminal, it can be easily reinforced without increasing the number of steps. In addition, it has an effect that the influence of stress due to the difference in material can be minimized.

FIG. 3 is a view for explaining the effect at the time of crimping, and shows a state in which the heater head 6 is thermocompression-bonded. When the flatness of the heater head 6 is pushed in parallel on the theoretical plane, it is considered that the end portion and the center portion are the same, but when the heater head 6 is concave due to thermal deformation, the end terminals are not connected. Stress concentrates and makes stable electrical connection difficult. Even in such a case, the dummy terminals 5a, 5b, 5
If c exists, the internal effective connection terminal 4 can maintain an electrically stable connection. Therefore, the outer end portions of the effective connection terminal portion can be connected to each other in the same manner as the central portion, and the pressure-bonding uniformity is increased over the entire surface of the effective connection terminal portion.

In FIG. 4, instead of the dummy terminals 5a, 5b and 5c, a resist material 7 on the FPC has a similar function.

In the mounting structure shown in FIG. 5, the LSI chip 8 is An-.
The structure is such that Sn eutectic or the like is connected to the FPC, and the effective connection terminal 4 and the terminal lead-out portion 1 of the liquid crystal panel are electrically connected via the anisotropic conductive film 2.

The mounting structure of FIG. 6 is a method in which the method of FIG. 5 is made higher in density, and the LS is formed on the liquid crystal panel terminal lead-out portion 1.
This is a structure in which an FPC equipped with the I-chip 8 is electrically connected through an anisotropic conductive film.

Since the mounting structure of FIGS. 5 and 6 is one product with multiple terminals and multiple chips, stable connection of both outer ends of the connection terminals will improve the yield rate exponentially.

[0013]

As described above, by disposing the reinforcing members at both outer ends of the connection terminal group of the FPC, disconnection due to stress or the like at both outer ends can be prevented, and a display device with high connection reliability can be obtained. . Further, both outer end portions of the effective connection terminal portion can be connected in the same manner as the central portion, and have a uniform connection strength, and have an effect of increasing the pressure bonding uniformity over the entire surface of the effective connection terminal portion. There is.

Therefore, it is possible to reduce defects due to stress due to the difference in thermal expansion coefficient that occurs when the FPC is upsized and has multiple terminals. In addition, it is resistant to mechanical peeling force and enables highly reliable electrical connection.

[Brief description of drawings]

FIG. 1 is a view seen from the side of a base film of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a crimping process diagram of the present invention.

FIG. 4 is a view in which the dummy terminal 5 of the present invention is replaced with a resist material 7.

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1. Liquid crystal panel terminal extraction part 2. Anisotropic conductive film 3. Base film 4. Effective connection terminal 5. Dummy terminal 6. Heater head 7. Resist material 8. LSI chip

Claims (4)

[Claims] 1. A flexible printed circuit board, wherein reinforcing members which are not involved in electrical connection are arranged at both outer ends of the connection terminal group. 2. The flexible printed circuit board according to claim 1, wherein the reinforcing member is made of the same material as the connecting terminal. 3. The flexible printed circuit board according to claim 1, wherein the reinforcing member is made of a resist material. 4. The flexible printed board connection terminal group according to claim 1, and the terminal lead-out portion for connecting the reinforcing member and the external circuit of the liquid crystal panel are electrically connected through an anisotropic conductive film. And a liquid crystal display device.