Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2000-12-20
2004-04-20
Chowdhury, Tarifur R. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S155000
Reexamination Certificate
active
06724448
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a liquid crystal device and a manufacturing method therefor, and more specifically, it relates to a structure of a vertical conducting portion formed between two substrates making up the liquid crystal device.
2. Description of the Related Art
In general, a conventional liquid crystal is formed by: forming electrodes and wires connected to the electrodes on two substrates, respectively; further forming alignment layers thereon; attaching the two substrates to each other via a sealing member and curing the sealing member, the substrates being compression-bonded so as to provide a desired gap between the substrates, thereby fixing the gap between the substrates; and injecting a liquid crystal inside the sealing member and sealing it.
In such a liquid crystal device, normally, one substrate is provided with a projecting portion that projects outward beyond an outer edge of the other substrate, and the wire connected to the electrode formed on a substrate surface is drawn out onto a surface of the projecting portion, a distal end portion of the wire being formed as an external terminal. At this time, there are cases where the projecting portions are formed on the two substrates, respectively, and the wires connected to the electrodes formed on the respective substrate surfaces are drawn out onto the surfaces of the respective projecting portions. In many cases, however, the projecting portion is formed only on one of the two substrates. And in this case, a vertical conducting portion for conductively connecting the electrode on the substrate, in which the projecting portion is not formed, to the external terminal on the projecting portion formed on the other substrate is provided. In the vertical conducting portion, there are some cases where a part of a sealing member for sealing a liquid crystal in between two substrates attached to each other is formed into a conductive area.
FIG.
5
and
FIG. 6
are a schematic sectional view and a schematic top plan view of a vertical conducting portion in the above liquid crystal display panel. A conducting region
130
a
that has been cured in a compression-bonded state is disposed between two transparent substrates
110
and
120
making up the liquid crystal display panel. The conducting region
130
a
is a part of the sealing member. In the conducting region
130
a
, spacers
131
composed of resin balls, glass fibers, glass balls, or the like for restricting a cell thickness of the liquid crystal display panel and the foregoing conductive particles
133
are scatteringly disposed, as shown in
FIG. 6. A
plurality of external wires
111
b
which are formed to be drawn onto the surface of a projecting portion
110
a
of the transparent substrate
110
and are formed of a transparent conductive member are formed in parallel on a surface of the transparent substrate
110
that is in contact with the conducting region
130
a
. Inner end portions
111
c
of the external wires
111
b
are in contact with the conducting region
130
a
of the sealing member. Internal wires
121
b
which are connected to electrodes, which are not shown, and extend toward an outer edge of the substrate are formed on a surface of the transparent substrate
120
. Outer end portions
121
c
of the internal wires
121
b
are in contact with the conducting region
130
a
. The conductive particles
133
in the conducting region
130
a
are in conductive contact with both the inner end portions
111
c
and the outer end portions
121
c
. Hence, the electrodes, not shown, which are formed on the surface of the transparent substrate
120
are conductively connected to the external wires
111
b
formed on the surface of the projecting portion
110
a
through the internal wires
121
b
and the conductive particles
133
.
The conventional liquid crystal display panel has been configured such that the outer edges of the alignment layers
113
and
123
are disposed farther inward than the area where the sealing member or the foregoing conducting region
130
a
is disposed in order to prevent the alignment layers
113
and
123
from interfering with conductive contact between the inner end portions
111
c
of the external wires
111
b
and the outer end portions
121
c
of the internal wires
121
b
, and the conductive particles
133
.
In recent years, however, with an increasing demand for liquid crystal display panels to provide larger display areas and reduced sizes, there has been increasing necessity for making the portions surrounding the display areas (the areas where the electrodes are arranged and formed on substrate surfaces) as narrow as possible in designing a liquid crystal display panel (thereby narrowing the frames of the liquid crystal display panels). To narrow the peripheral portion of a display area, the space between an outer edge of the display area and an inner edges of the vertical conducting portion must be also reduced. As a method for applying the alignment layers
113
and
123
, a cheap printing method, such as flexo printing or offset printing that exhibits lower patterning accuracy than photolithography, which is a patterning method for transparent electrodes, etc. is used. Therefore, in order to securely position the outer edges of the alignment layers
113
and
123
between the outer edge of the display area and the inner edge of the vertical conducting portion, it is required to design the space between the outer edge of the display area and the inner edge of the vertical conducting portion with accuracy as good as or better than the printing accuracy of the alignment layers. For this reason, a conventional manufacturing process has been having some limitation, which is attributable to patterning accuracy of the alignment layers, in achieving a narrower area surrounding the display area without adopting a method that leads to higher cost, such as changing a method for applying the alignment layers.
Accordingly, the present invention has been made with a view toward solving the above problem, and the object of the present invention is to provide a structure that enhances freedom of designing and allow a larger display area and a reduced size of a liquid crystal device, by adopting a structure of a vertical conducting portion that is capable of achieving a narrower portion surrounding the display area, without being affected by a patterning accuracy of the alignment layers.
SUMMARY OF THE INVENTION
To solve the problem described above, a liquid crystal device in accordance with the present invention is formed by a first substrate and a second substrate which have electrodes and alignment layers formed on surfaces thereof and are attached to each other with a liquid crystal sealed in therebetween, comprising: a first conductive member formed on a surface of a peripheral portion of the first substrate; a second conductive member formed on a portion on the second substrate that opposes the first conductive member; and a vertical conducting portion having a conductive material containing conductive particles for electrically conductive connection between the first conductive member and the second conductive member, wherein the alignment layer is formed such that it extends to cover the surface of at least one of the first conductive member and the second conductive member, and the conductive particles break through the alignment layer to be in conductive contact with the first conductive member and the second conductive member.
According to the present invention, since the conductive particles in the conductive member break through the alignment layers to contact the first conductive member and the second conductive member, it is no longer necessary to avoid the vertical conducting portion in forming the alignment layers as in the prior art, eliminating the restrictions on the positions of the outer edges of the alignment layers. As a result, design freedom in the peripheral portion of the display area of a liquid crystal device is enhanced, so that t
Akkapeddi P. R.
Chowdhury Tarifur R.
Harness & Dickey & Pierce P.L.C.
Seiko Epson Corporation
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