JP3246499B2 - Electrical connection structure and liquid crystal device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed circuit board (hereinafter abbreviated as FPC) and a liquid crystal device which are used for mounting a high-density, multi-terminal LCD panel and the like. . 2. Description of the Related Art Conventionally, a group of connection terminals of an FPC has been formed so as to face a terminal extraction portion for connection to an external circuit of a liquid crystal panel, and has been electrically connected. [0003] In the conventional FPC, all terminals are used as effective connection terminals. Therefore, when a stress is generated due to a difference in the thermal expansion coefficient between the base film of the FPC and, for example, a glass substrate, the maximum is required. There is a drawback that the connection terminal at the outer end is disconnected and causes a defect immediately. 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] An electrical connection structure according to the present invention comprises a flexible printed circuit board having terminals and a substrate having terminals. Electrical connection structure that is electrically connected by crimping via the outside, wherein the anisotropic outside of the terminal portion of the flexible printed board does not contribute to electrical connection with the terminal portion of the board. A member connected to the substrate via a conductive film is provided, and the member is wider than the terminal portion. In the liquid crystal device of the present invention, a flexible printed circuit board having terminals and a substrate of a liquid crystal panel having terminals are electrically connected to each other by pressure bonding with both terminals facing each other via an anisotropic conductive film. A liquid crystal device comprising: a flexible printed circuit board connected to the outside of the terminal via the anisotropic conductive film without contributing to the electrical connection with the terminal of the board; A member is arranged, and the member is wider than the terminal portion. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a view from the side of an FPC base film, and FIG. 2 is a sectional view thereof. 1 is a liquid crystal panel terminal extraction portion, 2 is an anisotropic conductive film, 3 is a base film,
Is an effective connection terminal, and 5 is a dummy terminal. When the dummy terminals 5 are provided in this manner, even if a shear stress is generated due to a difference in the thermal expansion coefficient between the base film 3 and the liquid crystal panel terminal extraction portion, a load is applied to the outermost dummy terminals 5. No load is applied to the inner effective connection terminal 4. Further, since the dummy terminal as the reinforcing member is made of the same material as the effective connection terminal, the reinforcement can be easily performed without increasing the number of steps. In addition, it has the effect of minimizing the effect of stress due to differences in materials. FIG. 3 is a view for explaining the effect at the time of pressure bonding, and shows a state in which the pressure bonding is performed by the heater head 6. When the flatness of the heater head 6 is pressed in parallel on a theoretical plane, it is considered that both ends and the center are the same. However, when the heater head 6 becomes concave due to thermal deformation, it is connected to an end terminal. Stress concentrates and makes electrical stable 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 ends of the effective connection terminal can be connected in the same manner as the center, and the uniformity of crimping can be increased over the entire surface of the effective connection terminal. FIG. 4 shows a structure in which a resist material 7 on an FPC has a similar function in place of the dummy terminals 5a, 5b and 5c. The mounting structure shown in FIG.
The structure is such that the connection is made to the FPC with Sn eutectic or the like, and the effective connection terminal 4 and the terminal extraction portion 1 of the liquid crystal panel are electrically connected via the anisotropic conductive film 2. The mounting structure shown in FIG. 6 is a method in which the method shown in FIG.
This is a structure in which an FPC on which the I chip 8 is mounted is electrically connected via an anisotropic conductive film. Since the mounting structure shown in FIGS. 5 and 6 constitutes one product with multiple terminals and multiple chips, the yield is improved by a power by the stable connection of the outer ends of the connection terminals. As described above, by arranging the dummy terminals at the outer ends of the connection terminal group of the FPC, the electrical open at the outer ends caused by the difference in the thermal expansion coefficient between the substrates can be reduced. Thus, an electrical connection structure with high connection reliability can be obtained. In addition, the outer end portions of the effective connection terminal portion can be connected in the same manner as the center portion, have a uniform connection strength, and have the effect of increasing crimp uniformity over the entire effective connection terminal portion. I have. Therefore, it is possible to reduce defects due to stress caused by a difference in thermal expansion coefficient when the FPC is enlarged and the number of terminals is increased. Further, it is strong against mechanical peeling force, and highly reliable electrical connection is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view seen from a base film side of the present invention. FIG. 2 is a sectional view of an embodiment of the present invention. FIG. 3 is a pressure-bonding process diagram of the present invention. FIG. 4 is a diagram in which a dummy terminal 5 of the present invention is replaced with a resist material 7; FIG. 5 is a view showing another embodiment of the present invention. FIG. 6 is a diagram showing another embodiment of the present invention. [Explanation of Codes] 1. LCD panel terminal extraction section 2. Anisotropic conductive film Base film4. Effective connection terminal 5. Dummy terminal 6. Heater head7. Resist material8. LSI chip

Claims (1)

(57) [Claims] An electrical connection structure in which a flexible printed board having a terminal portion and a substrate having a terminal portion are electrically connected to each other by crimping with both terminal portions facing each other via an anisotropic conductive film, Outside the terminal portion of the substrate, a member connected to the substrate via the anisotropic conductive film is disposed without contributing to electrical connection with the terminal portion of the substrate. An electrical connection structure that is wider than the terminals. 2. A liquid crystal device comprising: a flexible printed circuit board having a terminal portion; and a liquid crystal panel substrate having a terminal portion, wherein both the terminal portions are opposed to each other and electrically connected by crimping via an anisotropic conductive film. Outside the terminal portion of the printed board, a member connected to the substrate via the anisotropic conductive film without contributing to the electrical connection with the terminal portion of the substrate is arranged. A liquid crystal device having a width wider than a terminal portion.