Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2003-04-10
2004-08-10
Nguyen, Dung T. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S149000, C361S739000
Reexamination Certificate
active
06774971
ABSTRACT:
BACKROUND OF THE INVENTION
1. Technical Field Of The Invention
The present invention relates to a liquid crystal display and a method for producing the same.
2. Prior Art
Conventionally, a COG (chip-on-glass) module and a COF (chip-on-film) module have been publicly known as liquid crystal displays.
FIG. 11
shows a configuration of a COG module (wherein FIG.
11
(
a
) is a plan view and FIG.
11
(
b
) is a view taken along the line A—A of FIG.
11
(
a
)). The COG module shown in
FIG. 11
is composed of a liquid crystal displaying portion
43
that is obtained by overlapping a surface substrate
41
and a rear substrate
42
, to each of which conductive line (not illustrated) constituting a transparent pixel electrode
45
is applied, and sealing liquid crystal in pixel areas sectioned by sealing agents between the corresponding substrates
41
and
42
; and a circuit substrate portion
47
in which an LSI (IC)
46
connected electrically to the above-described transparent pixel electrode
45
is connected to an area in which terminals of the above-described transparent pixel electrodes
45
is provided on the surface substrate
41
or the rear substrate
42
, and a plurality of conductive lines of these transparent electrode
45
are integrated.
Transparent resin and transparent glass are used as the above-described surface and rear substrates
41
and
42
. However, since, in many cases, glass is employed, areas to which the LSI
46
is connected are provided on a glass substrate. Therefore, there may be cases where a liquid crystal display consisting of the above liquid crystal displaying portion
43
and circuit substrate portion
47
is called a “chip-on-glass” module.
The COG module employs a flexible cable such as FPC
49
as a cable for connection from a conductive line of the LSI
46
to the power source (not illustrated) side.
Also, the liquid crystal display in which the COF is used is shown in
FIG. 12
(wherein FIG.
12
(
a
) is a plan view, and FIG.
12
(
b
) is a sectional view taken along the line A—A in FIG.
12
(
a
)). The COF module is composed of a liquid crystal displaying portion
53
in which a surface substrate
51
and a rear substrate
52
having conductive line, which constitutes a transparent electrode, applied thereto are, respectively, overlapped with each other, and liquid crystal is poured and sealed in pixel areas sectioned by a sealing agent between both of the corresponding substrates
51
and
52
; and a circuit substrate portion
59
that forms conductive lines
55
of metallic copper, connected to conductive lines from the corresponding liquid crystal displaying portion
53
, on a circuit substrate
57
made of synthetic resin film such as expensive polyimide resin, etc., and connects an LSI (IC)
56
, which is connected electrically to the transparent pixel electrode of said liquid crystal displaying portion
53
, to an area in which the above-described conductive lines
55
of metallic copper are integrated.
The conductive lines of the LSI (IC)
56
on the above-described circuit substrate portion
59
are configured so as to be connected to the power source side via an anisotropic conductive film (not illustrated), etc. However, in the configuration shown in
FIG. 12
, since the LSI
56
is provided on a synthetic resin film, the same may be called a “chip-on-film” module.
In the liquid crystal display constructed as shown in
FIG. 12
, the LSI (IC)
56
is connected to the conductive lines in the order shown in FIG.
13
. First, as shown in FIG.
13
(
a
), a copper foil
60
is adhered to the surface of the circuit substrate
57
(FIG.
13
(
b
)), the same is etched after a masking agent
63
is coated (FIG.
13
(
c
)), and a pattern of copper conductive lines
55
is formed. Next, an ACF (Anisotropic Conductive Film)
58
is adhered to the pattern of the etched copper conductive lines
55
(FIG.
13
( )), and the LSI (IC)
56
is thermally pressure-fitted from above the ACF
58
(FIG.
13
(
f
)).
In the configuration of the COG module shown in
FIG. 11
, since the liquid crystal displaying portion
43
and the circuit substrate portion
47
are provided on the rear substrates
41
and
42
, the area of the circuit substrate portion
47
in which the LSI
46
of the COG module is mounted is increased, the area occupied by the circuit substrate portion
47
is increased in comparison with the liquid crystal displaying portion
43
that brings about its inherent features and functions as a liquid crystal display. Since the FPC
49
that is a flexible cable is disposed on the surface of the rear substrate
42
, the flexible property of the FPC
49
cannot be completely displayed, and since the circuit substrate portion (LSI-mounted part)
47
is provided on a glass substrate together with the liquid crystal displaying portion
43
, it is not possible to fold the circuit substrate portion
47
.
Also, in the configuration of the COF module, which is shown in
FIG. 12
, in order to form conductive lines
55
, having a minute thickness, of non-transparent copper on the circuit substrate
57
made of polyimide resin film being a flexible film as shown in
FIG. 13
, the cost of producing a mask to form conductive lines, and the cost for inspection of connecting electrically to the conductive lines after the conductive lines are formed are incidentally increased. In addition, since polyimide resin is expensive, and the product cost will be accordingly increased, which cannot be ignored as a problem.
Further, the circuit substrate
57
that is composed of copper conductive lines
55
and a polyimide resin film is non-transparent as shown in FIG.
13
(
f
), and there is a shortcoming by which the connected state between the copper conductive lines
55
and LSI
56
cannot be visibly confirmed.
Thus, since the COF module employs a number of production steps and uses expensive materials, there are many cases where the development costs cannot be depreciated in a case of producing custom products in a small lot.
Also, in the COF module shown in
FIG. 12
, it is necessary to prepare a photo mask to produce a circuit substrate portion
57
for connection of the LSI
56
, a metal mold for cutting the outer profile thereof, and special tools and fixtures to fix a soft polyimide resin film, and high initial costs are required. Also, since expensive ultra-thin polyimide films and ultra-thin copper foils
60
are used as the materials of the circuit substrate
57
, the unit price thereof is very expensive. In addition, since the circuit substrate materials and circuit conductive lines are not transparent, it is not possible to visibly check the connected state of the LSI
56
when it is mounted on the circuit substrate portion
57
.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a liquid crystal display that employs the COG technology, is able to mount LSIs in a narrow space and, after the LSIs are mounted, to visibly check the mounted state (that is, its electrically connected state) and the lighting of a picture displaying portion, and a method for producing the same. Also, it is another object of the invention to provide a liquid crystal display that has high reliability and whose production cost is lower, and a method for producing the same.
These objects of the invention can be achieved and solved by the following configurations (1) and (2):
(1) A liquid crystal display comprising: a liquid crystal displaying portion in which a first substrate having a transparent pixel electrode provided thereon and a second substrate having a transparent opposed pixel electrode provided thereon overlaps each other so that both the above-described electrodes are disposed so as to be opposed to each other, and liquid crystal is sealed in a pixel area between the above-described first substrate and the above-described second substrate; a hard transparent substrate having a transparent conductive electrode provided thereon; a circuit substrate portion that is mounted on the surface of the above-described hard transparent substra
Kowata Hideki
Ohta Akihiko
Shigeeda Akira
Shirato Yasuyuki
Intellectual Property Law Group LLP
Jackson Juneko
Lee Otto O.
Nanox Corporation
Nguyen Dung T.
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