Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1998-04-06
2001-01-09
Dudek, James A. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S152000, C349S151000
Reexamination Certificate
active
06172731
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a display device for use in an electronic appliance such as a FA appliance, AV appliance, OA terminal etc., as well as an advertisement display.
(2) Description of the Prior Art
The prior art will be described with reference to
FIGS. 1 through 4
.
FIG. 1
Is a perspective view showing a conventional display device;
FIG. 1A
is a view from the obverse side of the display device and
FIG. 1B
is a view from the reverse side thereof.
FIG. 2
contains diagrams showing the forces and their components when the input connector is inserted.
FIG. 3
is a sectional view showing a prior art display device.
FIG. 4
is a sectional view showing another prior art display device.
As shown in
FIG. 1
, the conventional display device comprises: a display panel
2
; a scan signal input circuit substrate
13
disposed along the length of one side of display panel
2
for inputting the scan signal to display panel
2
; and a data signal input circuit substrate
14
disposed along the length of the other side for inputting data to the display panel
2
. The display panel
2
is composed of a pair of glass substrates for inputting the scan signal and data, respectively, and a liquid crystal material sealed therein; each glass substrate has a pattern of electrode leads (designated at
3
in FIG.
2
), which consists of tin oxide, indium oxide or the like, formed on the opposing surface to the other. This pattern of electrode leads
3
is joined to a flexible circuit substrate
8
so that the display panel
2
is electrically connected to scan signal input circuit substrate
13
having, for example, an input connector
5
, electronic parts
9
, driver ICs
18
etc. provided thereon.
FIG. 2A
is a sectional view cut along a plane
300
—
300
in
FIG. 1A
, showing the detailed configuration of the above electric connection. In the figure, a glass terminal
4
of display panel
2
and scan signal input circuit substrate
13
are placed opposedly with a gap
16
therebetween so that pattern of electrode leads
3
formed on glass terminal
4
is connected with scan signal input circuit substrate
13
by flexible circuit substrate
8
. The joint between pattern of electrode leads
3
and flexible circuit substrate
8
is protected by resin
6
.
In this conventional arrangement the thus configured joint in some cases peeled off due to the stress generated in pattern of electrode leads
3
and/or flexible circuit substrate
8
extending across gap
16
when input connector
5
was handled f or attachment or removal. For example, suppose that a force f
0
is applied when input connector
5
is handled for attachment or removal as shown in FIG.
2
A. In this case, force f
0
can be decomposed into force component f
1
acting on spacer
15
and force component f
2
acting at the joint of flexible circuit substrate
8
. This force component f
2
would cause the peeling.
Next, this peeling force will be explained with reference to FIG.
2
B.
Force f
0
applied on input connector
5
can be decomposed into force component f
1
shown in expression (1) and force component f
2
shown in expression (2) as follows:
f
1
=(X/Y)·f
0
(1)
f
2
=[1−(X/Y)]·f
0
(2)
where f
0
: connector insertion force;
f
1
: spacer pressing force;
f
2
: stress;
X: distance between f
0
and f
2
; and
Y: distance between f
1
and f
2
.
This force component f
2
warps flexible circuit substrate
8
. If this bending is represented by an angle &thgr;, the component of force along flexible circuit substrate
8
which is deformed results in f
2
sin &thgr;. Further, as shown in
FIG. 2C
, this force causes a peeling force F of f
2
sin
2
&thgr;, thus separating flexible circuit substrate
8
from anisotropic conductive film
7
having pattern of electrode leads
3
formed on glass terminal
4
. Force component f
1
of force f
0
is borne by a bezel
12
. Here,
FIG. 2C
is an enlarged view of an encircled portion D in FIG.
2
A.
Various countermeasures have conventionally been taken against the above problem.
The first method is one in which, as shown in
FIG. 2A
, resin
6
of an epoxy or acrylic type is filled in the joint with glass terminal
4
so as to integrate display panel
2
with flexible circuit substrate
8
.
The second method is that disclosed in Japanese Patent Application Laid-Open Hei 4 No. 269,723, as shown in
FIG. 3
in which the gap between glass terminal
4
and scan signal input circuit substrate
13
is provided with resin
6
so as to fill up the space which might, otherwise, cause the deformation.
Further, the third method is disclosed in Japanese Patent Application Laid-Open Hei 8 No. 152,644, as shown in FIG.
4
. That is, glass terminal
4
and scan signal input circuit substrate
13
are made to abut each other at their end faces while a reinforcing plate
19
is disposed across the non-displaying area of display panel
2
and the entire surface of scan signal input circuit substrate
13
and bonded with resin
6
.
However, the first method cannot provide high enough strength to stop peeling, as already stated.
In the second method, the rigidity of the structure is enhanced since the gap between glass terminal
4
and scan signal input circuit substrate
13
is filled up with resin
6
. This method, however, needs a prolonged time for application and drying of resin
6
and handling will become difficult when scan signal input circuit substrate
13
needs to be detached for repair.
In the third method, the strength to stop peeling can be enhanced, but the handling will be degraded as in the second embodiment. Further, since reinforcing plate
19
is applied throughout the rear surface of scan signal input circuit substrate
13
, all electric parts such as driver ICs
18
etc., must be mounted on the obverse face of scan signal input circuit substrate
13
. This configuration constrains the arrangement of the parts and increases cost due to the use of reinforcing plate
19
.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a display device which is less costly in terms of parts and manufacturing, and still provides high enough strength for the fixture between the display panel and the circuit substrate for driving the panel, so as to prevent the electric connection between the display panel and circuit substrate from deteriorating under the stress generated between the display panel and circuit substrate when the connector is attached or removed and hence ensure high handling performance.
In order to achieve the above object, the present invention is configured as follows:
In accordance with the first aspect of the invention, a display device comprises:
a display panel;
a circuit substrate disposed, at the periphery of and beside, the display panel with a predetermined gap therebetween;
a flexible circuit substrate extending across the gap to connect the display panel with the circuit substrate; and
a reinforcing plate having a plurality of connecting parts to be joined to the circuit substrate and a fixture portion to be fixed to the display panel, and is characterized in that the reinforcing plate is fixed to the circuit substrate and display panel, on the side opposite to the one on which the flexible circuit substrate is provided.
In accordance with the second aspect of the invention, the display device having the above first feature is characterized in that the connecting parts of the reinforcing plate are fixed by soldering at positions where the joint will not interfere electronic parts mounted on the circuit substrate.
In accordance with the third aspect of the invention, the display device having the above first feature is characterized in that the reinforcing plate is made of metal.
In accordance with the fourth aspect of the invention, a display device comprises:
a display panel;
a circuit substrate disposed, at the periphery of and beside, the display panel with a predetermined gap therebetween;
a flexible circuit substrate ex
Kawahigashi Yoshitsugu
Murakami Akira
Nagano Mitsuru
Takahashi Nobuaki
Dudek James A.
Nixon & Vanderhye P.C.
Sharp Kabushiki Kaisha
Ton Toan
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