Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-06-11
2001-04-03
Dudek, James A. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S149000, C349S150000
Reexamination Certificate
active
06211936
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to a liquid crystal display device in which a flexible printed circuit board is thermally pressure-contacted to a liquid crystal display panel through an electrically anisotropic film, and to a method of making the same.
A liquid crystal display device is thin in thickness and light in weight so that it has been widely used for various small-size, hand-held-type data processing equipment. As shown in
FIG. 7
, a liquid crystal device includes a liquid crystal display panel
16
which consists of a circuit array substrate
11
, a counter substrate
12
provided opposite to the array substrate
11
and a liquid crystal material (not shown) located between the array and counter substrates
11
and
12
. On the array substrate
11
, scanning and signal lines (not shown) are disposed to cross each other at a right angle, and pixel electrodes and switching circuits to supply video signals to the electrodes are provided in the vicinities of the cross points of the scanning and signal lines. The scanning and signal lines are coupled to electrically connecting terminals
15
at an edge portion of the array substrate
11
in order to supply signals to, and to derive signals from, the liquid crystal display panel
16
. A common electrode is provided on the counter electrode
12
. Polarizers
13
and
14
are attached to outer surfaces of the array and counter substrates
11
and
12
, respectively. In a driver-monolithic-type liquid crystal display panel, however, driver circuits are disposed at surrounding areas of an image forming region in the array substrate.
A flexible printed circuit board (“FPC”)
61
consists of a base film
1
, an adhesive layer
2
applied on the base film
1
, a printed signal line layer
3
made of copper foil along a surface of the layer
2
, and a protective film
4
to protect the signal line layer
3
. An electrically anisotropic conductive film (“ACF”)
52
is provided to connect the terminals
15
to the FPC
61
. The ACF
52
is made of a thermosetting isolation layer and electrically conductive particles dispersed in the isolation layer. The signal line layer
3
is thermally pressure-contacted to the terminals
15
through the ACF
52
at the edge portion of the array substrate
11
.
Since the array substrate
11
has a sharp edge
50
as shown in
FIG. 5
, the signal line layer
3
of the FPC
61
is often broken by the edge
50
during their assembling process. To avoid this, an additional process is required to cut it out to form a slope
51
as shown in FIG.
6
.
Since the signal line
3
is not entirely covered with the protective film
4
, it may be still damaged during the assembling process.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a liquid crystal display device with a structure to eliminate the edge-cutting process and a method of making the same. An object of the invention is to provide a liquid crystal display device which is capable of preventing an FPC (flexible printed circuit board) from being broken and a method of making the same.
According to one aspect of the invention, a liquid crystal display device includes a liquid crystal display panel provided with two opposite electrode substrates and a liquid crystal material put between the electrode substrates. One of the electrode substrates has a plurality of electrically connecting terminals at its edge portion. The terminals are connected to a signal line layer of an FPC through an ACF (electrically anisotropic conductive film). The ACF is made of a thermosrtting isolation layer and electrically conductive particles dispersed therein. The ACF has a connecting portion for the terminals and the FPC and an extending portion therefrom. Thus, when the FPC, the ACF and the terminal are thermally pressured, the signal line layer of the FPC is connected to the terminals through the ACF. During this process, the connecting portion of the ACF is pushed out, gradually becomes solid and forms a support member at the edge of the electrode substrate. The support member is semicircular in shape due to the surface tension of the ACF.
The support member avoids interference between the edge of the electrode substrate and the signal line layer of the FPC. The support member also prevents the FPC from being broken when the FPC is bent around the edge of the electrode substrate. Further, the extending portion of the ACF entirely covers the signal line layer and protect it after turning into a solid.
According to another aspect of the present invention, a method of making a liquid crystal display device includes a thermally pressure-connecting process by which a liquid crystal display panel is connected to an FPC through an ACF. The liquid crystal display panel includes two opposite electrodes and a liquid crystal material held between them. One of the electrode substrates has a plurality of electrically connecting terminals. The FPC includes a signal line layer. The ACF is made of a thermosetting isolation layer and electrically conductive particles dispersed therein. The ACF has an ordinary portion to connect the terminals of the electrode substrate to the signal line layer of the FPC and an extra portion extending therefrom. After the FPC and the ACF are set in alignment with the terminals, those components are thermally pressure-connected to each other by applying a hot press tool. The connecting portion of the ACF is pushed out, becomes semicircular in shape at the edge of the electrode substrate due to surface tension, grows gradually solid, and finally forms a support member for the FPC and the edge. At the same time the extending portion of the ACF is hardened and protects the signal layer of the FPC. Thus, this method of making the liquid crystal display device does not require the carrying out of the conventional process to cut out the edge portion of the electrode substrate.
REFERENCES:
patent: 4985663 (1991-01-01), Nakatani
patent: 5089750 (1992-02-01), Hatada et al.
patent: 5668700 (1997-09-01), Tagusa et al.
patent: 8-271925 (1996-10-01), None
Dudek James A.
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
LandOfFree
Liquid crystal display device and method of making the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal display device and method of making the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal display device and method of making the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2473099