Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-08-17
2001-02-20
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S150000, C349S058000, C349S062000
Reexamination Certificate
active
06191838
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Industrial Field of the Invention
The present invention relates to a connecting structure of a circuit board, an electro-optical device, electronic apparatus provided with the same, and a manufacturing method for an electro-optical device.
2. Description of the Related Art
An electro-optical device such as a liquid crystal display device employs an integrated circuit (IC) device, on which driving IC components are mounted, to connect its driving circuit to a liquid crystal display (LCD) panel. Typical IC devices used for this purpose include a chip-on-film (COF) type wherein a flexible wiring board using a so-called “tape automated bonding (TAB) package (also known as a tape carrier package (TCP)” is connected to an LCD panel, and a chip-on-glass (COG) type wherein driving IC components are directly connected to a glass substrate. For instance, the wiring board employing the TCP is advantageous in that it is smaller and thinner than other types of packages, which makes it suited for high-density packaging, and the board is flexible to permit itself to be bent for packaging. These advantages allow the wiring board to find applications in a variety of types of electronic apparatus, including electro-optical devices.
Diverse types of terminals for connection to driving ICs are formed on wiring board employing the TCPs (herein after referred to as “TCP boards”). Hence, to configure electronic apparatus or the like, the terminals of a TCP board are electrically connected to the terminals of another circuit board.
In general, the packaging mode as set forth below is used to connect the terminals of the TCP board and the terminals of another circuit board. With a conductive member such as an anisotropic rubber connector provided between the terminals of the TCP board and the terminals of another circuit board, the TCP board and another circuit board are pressed in a connecting direction thereby to press the terminals of the TCP board and the terminals of another circuit board into contact via the conductive member. This accomplishes electrical connection between the terminals of the TCP board and the terminals of another circuit board.
The connecting structure set forth above, however, has been posing a problem since a flexible wiring board such as the TCP board and another circuit board are pushed against each other to bring them into contact so as to enable the electrical connection. More specifically, in a structure or an environment wherein an adequate force for bringing the flexible wiring board and another circuit board into close contact with each other cannot be secured, if the boards are subjected to external forces, especially vibrations or shocks, electrical connection may not be successfully accomplished, resulting in a continuity failure.
Furthermore, if a rubber connector formed of anisotropic conductive rubber is used for connecting a terminal on an electro-optical device, for example, an LCD panel, to a terminal of a flexible wiring board, then a failure of electrical connection may occur if vibrations, shocks, or other types of external forces are applied.
In addition, a dedicated press-in-contact member such as a case must be used to secure a sufficient contact pressure between a terminal of the flexible wiring board and a terminal of another board, adding to the number of components. Furthermore, to use such a press-in-contact member, the flexible wiring board and another circuit board must be compression-bonded by using a pressing jig. Hence, at locations where direct contact pressure cannot be secured, it is impossible to improve the reliability of contact, leading to a continuity failure.
Accordingly, an object of the present invention is to provide: a circuit board connecting structure which enables contact pressure to be secured without the need for employing a special press-in-contact member so as to achieve higher contact reliability in connecting a circuit board such as a flexible wiring board and another circuit board, which can be configured with less components; an electro-optical device; electronic apparatus provided with the same; and a manufacturing method for an electro-optical device.
SUMMARY OF THE INVENTION
To this end, according to one aspect of the present invention, there is provided a circuit board connecting structure for electrically connecting a conductive terminal provided on a first circuit board and a conductive terminal provided on a second circuit board, including:
a conductive member which is disposed between the first circuit board and the second circuit board that oppose each other, and electrically connects the respective conductive terminals;
a structural member disposed on an opposite side from a side where the second circuit board is disposed, in relation to the first circuit board; and
a spacing member disposed between the structural member and the first circuit board.
With this arrangement, the respective conductive terminals are electrically connected by the conductive member installed between the first and second circuit boards. In bringing the conductive member and the respective conductive terminals into contact, the spacing member provided between the structural member and the first circuit board, and the structural member permit adequate contact pressure between the respective conductive terminals and the conductive member.
Thus, the reliable contact with the conductive member achieved by the contact pressure set forth above improves the reliability of the contact between the conductive member and the respective conductive terminals. This ensures successful electrical connection between the conductive terminal of the first circuit board such as the flexible wiring board and the conductive terminal of the second circuit board.
Preferably, in the circuit board connecting structure in accordance with the present invention, the spacing member is provided such that it is associated with at least a part of an area wherein the conductive member is disposed, and a part of the first circuit board is held between the spacing member and the conductive member. With this arrangement, the spacing member is provided such that it is associated with a position where the conductive member is disposed; hence, contact pressure can be applied directly to a position where the conductive member is brought into contact with the respective conductive terminals, leading to further improved contact reliability.
Preferably, in the circuit board connecting structure in accordance with the present invention, the spacing member is formed to be larger than the conductive member in the direction of a surface of the first circuit board. With this arrangement, the spacing member formed to be larger than the conductive member makes it possible to maximize the contact pressure of the second circuit board with respect to the conductive member, permitting higher contact reliability.
Preferably, in the connecting structure of a circuit board in accordance with the present invention, the spacing member is formed of an elastic member. With this arrangement, elastically deforming the elastic member by the structural member allows the contact pressure to be further increased by taking advantage of the elastic force, thus leading to improved contact reliability.
Preferably, in the circuit board connecting structure in accordance with the present invention, the conductive member is formed of an elastic member. With this arrangement, the conductive member elastically deforms in response to a pressure applied to the first and second circuit boards, and the elastic force increases the contact pressure of a contacted portion. The pressing force is generated by the structural member and the spacing member. Hence, the conductive member and the respective conductive terminals can be brought into closer contact, with resultant improved contact reliability.
Preferably, in the circuit board connecting structure in accordance with the present invention, the conductive member has a plurality of rows of conductive portions arranged in a direction
Harness & Dickey & Pierce P.L.C.
Parker Kenneth
Qi Mike
Seiko Epson Corporation
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