Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Including integrally formed optical element
Reexamination Certificate
2001-07-09
2003-09-02
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Including integrally formed optical element
C438S031000, C438S032000, C349S149000
Reexamination Certificate
active
06613599
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to an electro-optical device, a method of manufacturing an electro-optical device, a liquid crystal device, a method of manufacturing a liquid crystal device and an electronic apparatus, and particularly to a structure and a manufacturing method for an electro-optical device comprising a wiring substrate connected to an electro-optical panel substrate.
2. Description of the Related Art
At present, liquid crystal devices are widely used for electronic apparatuses such as cellular telephones, potable electronic terminal units, etc. In many cases, a liquid crystal device is used for displaying information by a character, a numeral, a pattern, or the like.
A liquid crystal device generally comprises a pair of liquid crystal substrates each having an electrode formed on the inner side thereof, and a liquid crystal held between the pair of substrates so that the orientation state of the liquid crystal is controlled by controlling the voltage applied to the liquid crystal to modify light incident on the liquid crystal according to the liquid crystal orientation state. The liquid crystal device requires a liquid crystal driving IC, i.e., a semiconductor chip, for controlling the voltage applied to the liquid crystal, the IC being mounted directly on one of the liquid crystal substrates or indirectly thereon through a mounting structure such as a flexible wiring board, or a printed circuit board.
In connecting the liquid crystal driving IC indirectly to one of the liquid crystal substrates through the mounting structure, for example, the liquid crystal driving IC is mounted on a flexible printed board comprising a wiring pattern and electrode terminals to form the mounting structure which is then connected to one of the substrates of the liquid crystal device. In this case, the mounting structure can be connected to one of the substrates of the liquid crystal device by using solder.
In the above-described liquid crystal device, in some cases, a liquid crystal panel or a plastic frame functioning as a light guide for a back light is provided on the back side of the display surface of the liquid crystal substrate. In this case, the frame is possibly damaged by heating during soldering of the liquid crystal substrate and the mounting structure.
Particularly, it has recently been demanded to eliminate conventional lead-containing solder from electronic apparatuses in connection with environmental problems. In order to comply with this demand, various types of lead-free solder (binder alloys substantially not containing lead) have already been developed. However, conventional lead-containing solder has a melting point of about 183° C., while lead-free solder has a melting point of about 210 to 230° C. Therefore, the substitution of lead-free solder for conventional solder increases the occurrence probability of damage to the frame or deteriorates the degree of the damage to the frame because the melting point is increased. For these reasons, a conventional manufacturing process cannot be used as it is, necessitating a change of the manufacturing process in some cases.
Accordingly, the present invention has been achieved for solving the above problems, and an object of the present invention is to provide a structure and a manufacturing method capable of preventing thermal damage to a frame in an electro-optical device such as a liquid crystal device.
SUMMARY OF THE INVENTION
In order to achieve the object, in accordance with a first aspect of the present invention, an electro-optical device comprises an electro-optical panel substrate, a first wiring substrate mounted on the electro-optical panel substrate, a second wiring substrate connected to the first wiring substrate, and a frame arranged between the electro-optical panel substrate and the second wiring substrate, wherein the first wiring substrate is conductively connected to the second wiring substrate with a bonding metal, and a heat insulating layer is provided between the frame and the connection region between the first and second wiring substrates.
In the present invention, by providing the heat insulating layer between the connection region and the frame, heat transmission to the frame can be suppressed during conductive connection between the first and second wiring substrates with the bonding metal, thereby preventing damage such as thermal deformation or thermal deterioration of the frame. Also, providing the heat insulating layer prevents heat transmission from the connection region between the first and second wiring substrates to the frame to facilitate heating of the bonding metal, thereby facilitating the connecting work with the bonding metal and improving the quality of the bonded state of the connection region.
In accordance with a second aspect of the present invention, an electro-optical device comprises an electro-optical panel substrate, a plurality of first wiring substrates mounted on the electro-optical panel substrate, a second wiring substrate connected to the plurality of first wiring substrates, and a frame arranged between the electro-optical panel substrate and the second wiring substrate, wherein the plurality of first wiring substrates are conductively connected to the second wiring substrate with a bonding metal in different directions, and a heat insulating layer is provided between the frame and the connection regions between the first wiring substrates and the second wiring substrate.
In the present invention, since the plurality of first wiring substrates conductively connected to the second wiring substrate in different directions are provided, the work of conductively connecting at least one of the first wiring substrates to the second wiring substrate must be performed on the frame, and thus the heat insulating function of the heat insulating layer between the frame and the connection region becomes particularly effective.
In accordance with a third aspect of the present invention, an electro-optical device comprises an electro-optical panel substrate, a plurality of first wiring substrates mounted on the electro-optical panel substrate, a second wiring substrate connected to the plurality of first wiring substrates, and a frame arranged between the electro-optical panel substrate and the second wiring substrate, wherein the electro-optical panel substrate has a peripheral shape having a plurality of side edges, the plurality of first wiring substrates are conductively connected to the second wiring substrate with a bonding metal from the different side edges of the electro-optical panel substrate, and a heat insulating layer is provided between the frame and the connection regions between the first wiring substrates and the second wiring substrate.
In the present invention, since the plurality of first wiring substrates conductively connected to the second wiring substrate from different side edges of the electro-optical panel substrate are provided, the work of conductively connecting at least one of the first wiring substrates and the second wiring substrate must be performed on the frame, and thus the heat insulating function of the heat insulating layer between the frame and the connection region becomes particularly effective.
In accordance with a fourth aspect of the present invention, an electro-optical device comprises an electro-optical panel substrate, a plurality of first wiring substrates mounted on the electro-optical panel substrate, a second wiring substrate connected to the plurality of first wiring substrates, and a frame arranged between the electro-optical panel substrate and the second wiring substrate, wherein the first wiring substrates are conductively connected to the second wiring substrate with a bonding metal, the first wiring substrates or the second wiring substrate nearer to the frame than the connection regions between the first wiring substrates and the second wiring substrate has a thickness of about 50 &mgr;m or less, and a heat insulating layer is provided between th
Harness & Dickey & Pierce P.L.C.
Nelms David
Seiko Epson Corporation
Tran Long
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