Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2000-06-12
2004-02-10
Dudek, James (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S149000, C349S156000, C349S042000
Reexamination Certificate
active
06690442
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display in which a pair of insulating substrates are bonded so as to interpose a liquid crystal layer between the pair of insulating substrates, and more particularly to a shape of inner connecting electrodes of counter electrodes.
In a liquid crystal display using an array substrate on which transfer electrodes are formed by patterning a conductive thin film that has been formed by the last step of forming a conductive film in a step of manufacturing an array substrate, the transfer electrode for supplying a common electrical potential to common electrodes on a counter substrate has a structure in which the film thickness of the laminated layers in the center portion of the transfer electrode is allowed to have the same thickness as the peripheral portion thereof.
As illustrated in
FIG. 4
, in the structure of the conventional transfer electrode, in the case where an electrical potential is supplied from a transfer electrode
2
on an insulating substrate
1
to a common electrode (conductive thin film
11
) on a counter substrate
10
through a conductive material
9
and the common electrode potential is supplied to the transfer electrode
2
through a conductive metal film
3
formed in the second step of forming a conductive film on the insulating substrate
1
, the conductive metal film
3
which is electrically connected to a conductive thin film
6
formed in the last step of forming a conductive film of the insulating substrate
1
via a contact hole
7
on the periphery of the transfer electrode
2
, and as shown in
FIG. 4
, the conductive metal film
3
is provided beneath the conductive thin film
6
in such a manner so as to reach substantially the center portion of opening of the transfer electrode. Accordingly, not only an insulating film
5
which is formed after the step of forming the conductive metal film formed in the first step of forming a conductive film on the insulating substrate
1
, but also an insulating film
4
which is formed after the step of forming the conductive metal film
3
, are respectively provided beneath the conductive thin film
6
of the transfer electrode; thus, the film thickness of the laminated layer in the center portion of the transfer electrode is allowed to have the same film thickness as the peripheral portion thereof.
The above-mentioned conventional arrangement has exemplified the case where a common electrode potential is supplied to the transfer electrode through the conductive metal film
3
formed in the second step of forming a conductive film on the insulating substrate
1
. Also in the case where the electrical potential is supplied to the transfer electrode through another conductive metal film, the conductive metal film and the insulating film are provided so as to reach substantially the center portion of the opening of the transfer electrode; therefore, the film thickness of the laminated layer in the center portion of the transfer electrode is allowed to have the same film thickness as the peripheral portion thereof.
However, in the above-mentioned construction where the film thickness of the laminated layer in the center portion of the transfer electrode is allowed to have the same film thickness as the peripheral portion thereof, in the case where, upon joining to the counter substrate, compressive deformation of a conductive material applied to the transfer electrode is insufficient, the cell gap in the vicinity of the transfer electrode tends to become thicker. As a result, a change in the panel transmittance locally occurs; this causes irregularity in luminance, resulting in degradation in the yield, and in the case when an attempt is made to confirm deformation under compression of the conductive material from the rear face side, since the gap portion of the metal film is small and since the insulating films are interpolated, it is difficult to make an appropriate confirmation.
The present invention has been made so as to solve the above-mentioned problems, and its objective is to make the cell gap in the vicinity of the transfer electrode uniform so that the local change in the panel transmittance is prevented, the uniformity of luminance is improved, and the yield is also improved. Moreover, the gap portion between the metal films is made greater and the insulating film is not interpolated in the gap portion; thus, it is possible to easily confirm deformation under compression of the conductive material from the rear face side of the array substrate.
SUMMARY OF THE INVENTION
One aspect of the liquid crystal display of the present invention includes:
a first insulating substrate;
display pixels formed in such a manner as to be arranged in array like shape on the first insulating substrate, said display pixels having pixel electrodes electrically connected to each other;
a counter substrate formed on a second insulating substrate on which common electrodes are formed;
a liquid crystal layer interposed between the first insulating substrate and the second insulating substrate, the first insulating substrate and the second insulating substrate being bonded each other;
a transfer electrode for supplying a common electrical potential to common electrodes on the second insulating substrate through a conductive material;
wherein the transfer electrode is formed by patterning a conductive thin film that has been formed by the last conductive film forming process of the first insulating substrate;
wherein a second conductive metal film, which has been formed in the second conductive film forming process of the first insulating substrate, and is connected to the common electrode potential, and the conductive thin film are connected to each other on the periphery of the transfer electrode through a contact hole or through a direct contact, and the conductive thin film is directly formed on the first insulating substrate at one portion of the center portion of the opening of the transfer electrode.
In the liquid crystal display mentioned above, on a periphery of the transfer electrode, the first conductive metal film is preferably placed inside the first insulating film that is formed after the film forming process of the first conductive metal film and the second insulating film that is formed after the film forming process of the second conductive metal film that has been formed in the first conductive film forming process of the first insulating substrate.
The other aspect of a liquid crystal display of the present invention includes:
a first insulating substrate;
display pixels formed in such a manner as to be arranged in array like shape on the first insulating substrate, said display pixels having pixel electrodes electrically connected to each other;
a counter substrate formed on a second insulating substrate on which common electrodes are formed;
a liquid crystal layer interposed between the first insulating substrate and the second insulating substrate, the first insulating substrate and the second insulating substrate being bonded to each other;
a transfer electrode for supplying a common electrical potential to common electrodes on the second insulating substrate through a conductive material;
wherein said transfer electrode is formed by patterning a conductive thin film that has been formed by the last conductive film forming process of the first insulating substrate;
wherein a first conductive metal film, which has been formed in the first conductive film forming process of the first insulating substrate, and is connected to the common electrode potential, and the conductive thin film are connected to each other on the periphery of the transfer electrode through a contact hole or through a direct contact, and the conductive thin film is directly formed on the first insulating substrate at one portion of the center portion of the opening of the transfer electrode.
The still other liquid crystal display of the present invention includes:
a first insulating substrate;
display pixels formed in such a manner as to be arranged in
Endo Yukio
Hashiguchi Takafumi
Kohtaka Satoshi
Advanced Display Inc.
Dudek James
Nguyen Hoan
LandOfFree
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