Adhesive lamination useful in making circuit board structures

Adhesive bonding and miscellaneous chemical manufacture – Methods – Plaster board making

Reexamination Certificate

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C428S041700, C428S041900, C428S101000, C428S202000, C428S901000, C156S230000, C156S249000, C156S290000, C156S297000, C156S300000, C156S301000, C345S087000

Reexamination Certificate

active

06475314

ABSTRACT:

BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention is directed to the field of manufacturing display devices such as liquid crystal display devices, EL display devices and the like. The invention relates to a production method for an adhesive lamination for adhering films (such as TAB films), at least having electrodes, to elongated circuit boards, a production method for a circuit board using the adhesive lamination as well as relating to a display device using the circuit board and a production method for the display device.
(2) Description of the Prior Art
Conventional liquid crystal display (LCD) devices are formed of an LCD panel having a multiple number of TAB films electrically connected thereto and some elongated circuit boards electrically connected to these multiple number of TAB films.
The method of electrically connecting these multiple number of TAB films to the elongated circuit board is briefly described below.
First, in order to position a multiple number of TAB films to the elongated circuit board at predetermined positions, a strip of adhesive tape which is composed of a separation sheet and an adhesive layer and is wound up as in a reel, is cut into the length which extends across a plurality of TAB films provided on one side of the LCD panel, and the thus cut adhesive tape is applied directly on one elongated circuit board in parallel therewith.
Then, the separation sheet is removed to expose the adhesive layer, and the plural TAB films jointed to the LCD panel are positioned relative to the circuit board so that the electrode terminals on both sides correspond to each other. In this arrangement, the TAB films are laid over the circuit board and pressed on the area with the adhesive layer against the circuit board so that the TAB films are adhered and fixed onto the circuit board.
Thereafter, the electrode terminals of TAB films are electrically joined with solder to those of the circuit board.
Recently, a proposal has been made in which the frame of the display window for the LCD device is made narrower to improve the effective area of the display. However, in the above conventional art, it was impossible to make the width of the circuit board narrower.
Illustratively, in the proposed configuration, it is necessary to provide a number of electronic parts such as capacitors, buffer ICs, operational amplifiers, densely and compactly on the circuit board. It is also necessary to provide holes for screws which fix the circuit board to the plastic chassis, or to form cutouts for the fixture of the LCD panel to the plastic chassis by engaging bezel claws. However, the above prior art configuration suffered from problems in that the adhesive layer tended to rise up from the surface of the board near the electronic parts or the adhesive layer blocked the holes for screws, and cutouts. Therefore, it became impossible to apply the tape with an adhesive layer, onto the circuit board without modification.
In order to solve the problems, there is a method of providing a TAB film onto the circuit board without making a plurality of adhesive patches corresponding to the electrode terminal portions of the TAB films.
However, since in this method, plural adhesive patches were sporadically distributed without corresponding to the positions of electrode terminal portions of the TAB films, when the electrode terminals of the TAB films were soldered to those of the circuit board, the film terminals near areas with no adhesive layer tended to rise up so that soldering failure was likely to occur.
Even in the case where the soldering was performed well, since the uniting strength was weak in the areas where no adhesive layer was provided, TAB films tended to separate or the soldering tended to become disconnected due to tensile stress which could occur during assembly of the LCD device.
Further, since the adhesive layer was formed patch by patch on the circuit board, the efficiency of the assembly was low, thus raising the cost.
SUMMARY OF THE INVENTION
The present invention has been achieved in view of the above problems, and it is therefore an object of the present invention to provide an adhesive lamination which is composed of a number of patches of an adhesive layer and is applied across a plurality of circuit boards by making the patches corresponding to predetermined positions on the circuit boards, thus making it possible to reduce the cost and improving the efficiency of the operation of applying the adhesive layer to the circuit board, as well as improving the reliability of electrical connection between TAB films and the circuit boards.
It is another object of the invention to provide a production method for a circuit board which by using the adhesive lamination, makes it possible to produce a circuit board with an adhesive layer attached thereon, at high work efficiency at low cost.
It is a further object of the invention to provide a liquid crystal display device and a production method therefore wherein it is possible to make the frame of the display window narrower and compact and improve the reliability of electrical connection by using the above circuit board with an adhesive layer attached thereon.
It is a still another object of the invention to provide a production method for a liquid crystal display device which is excellent in the work efficiency and enables the production of inexpensive liquid crystal display devices by forming an anisotropically conductive adhesive layer of a circuit board chain.
In order to attain the above object, the present invention includes the following configurations and devices.
In accordance with the first aspect of the invention, an adhesive lamination comprises patches of an adhesive layer which correspond to predetermined positions on a plurality of circuit boards, and is configured so that the adhesive layer is applied across the plurality of circuit boards.
In accordance with the second aspect of the invention, an adhesive lamination having the first feature, further comprises: a first separation sheet off an elongated rectangle; and a second separation sheet, and is characterized in that the patches of an adhesive layer are of an elongated rectangle, formed between the first and second separation sheets and are arranged on the first separation sheet so that the length of thee patch of the adhesive layer is approximately parallel to the short side of the first separation sheet.
In accordance with the third aspect of the invention, an adhesive lamination having the second feature is characterized in that the adhering strength between the first separation sheet and the adhesive layer is greater than that between the second separation sheet and the adhesive layer.
In accordance with the fourth aspect of the invention, an adhesive lamination having the second or third feature is characterized in that a plurality of the first separation sheets are provided on the second separation sheet, and the first separation sheets are repeatedly laid out or arranged facing one another.
In accordance with the fifth aspect of the invention, an adhesive lamination having the second or third feature is characterized in that a plurality of the first separation sheets are provided on the second separation sheet, and each of the first separation sheets is shaped in a comb-like form so that a pair of the first separation sheets are laid out mated to one another.
In accordance with the sixth aspect of the invention, an adhesive lamination having the second or third feature is characterized in that the patches of the adhesive layer formed on the first separation sheet are arranged at intervals corresponding to that of the circuit boards arranged in the circuit board chain which is formed of a series of circuit boards.
In accordance with the seventh aspect of the invention, an adhesive lamination having the second or third feature is characterized in that the adhesive layer is formed so that each film, at least having electrodes, corresponds to one patch of the adhesive layer.
In accordance with the eighth aspect of the inve

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