Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-06-16
2004-09-28
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S190000, C349S154000, C349S113000
Reexamination Certificate
active
06798485
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device with a metal reflective film and, more particularly, to a structure in which, when a liquid crystal display device is manufactured by sealing a liquid crystal injection hole after a liquid crystal is injected between substrates, an operation of sealing the injection hole can be reliably performed.
2. Description of the Related Art
As shown in
FIG. 7
as a conventional configuration of a liquid crystal display device, a liquid crystal display device
3
obtained by sealing a liquid crystal between a pair of substrates
1
and
2
is known. In the exemplified liquid crystal display device
3
, a sealing material
4
consisting of a resin and annularly arranged along the peripheral portions of the substrates
1
and
2
is interposed between the substrates
1
and
2
, and a liquid crystal is sealed in a space surrounded by the sealing material
4
and the substrates
1
and
2
.
Projection portions
5
obtained by partially projecting the sealing material
4
on the center side of one end face of the substrates
1
and
2
(on the center side of the right end face in
FIG. 7
) toward the end face side of the substrates
1
and
2
are formed to be spaced apart from each other. These projection portions
5
are caused to reach the end faces of the substrates
1
and
2
to form a liquid crystal injection portion
6
. A resin is filled in the liquid crystal injection portion
6
to form a sealed portion
7
, and the liquid crystal injection portion
6
is stopped up.
When the liquid crystal display device
3
shown in
FIG. 7
is of a reflection type, as shown in
FIG. 8
, a reflective layer
8
is formed on the rear surface side of the substrate
2
.
When operations of injecting a liquid crystal and sealing the liquid crystal are performed to the reflection type liquid crystal display device
3
, the operations are performed by, e.g., the procedures described below.
Pairs of substrates
1
and
2
, as shown in
FIG. 9
, obtained in a state in which no liquid crystal is injected and before a sealed portion
7
is formed (i.e., the substrates
1
and
2
in which the injection portion
6
of the sealing material
4
is open) and a vessel
11
in which a liquid crystal
10
is saved are prepared separately from each other.
The pairs of substrates
1
and
2
are made upside down and kept above the vessel
11
. This structure as a whole is put in a vacuum atmosphere such as an evacuated furnace. The pairs of substrates
1
and
2
are moved downward to dip the peripheral portions of the liquid crystal injection portions
6
of the substrates
1
and
2
into the liquid crystal
10
. In this case, since a gap between each pair of substrates
1
and
2
is very small, the liquid crystal
10
can be slightly drawn into the gap between the substrates
1
and
2
from the liquid crystal injection portion
6
by capillary phenomenon.
Upon completion of this operation, when the atmosphere around the vessel
11
and the pairs of substrates
1
and
2
is returned from the vacuum atmosphere to the atmospheric atmosphere, the liquid crystal
10
can be drawn into the entire gap between the substrates
1
and
2
by using a pressure difference between the pressure in the vacuum state between the substrates
1
and
2
and the atmospheric pressure outside the substrates
1
and
2
.
Upon completion of the liquid crystal drawing operation into the gaps between the pairs of substrates
1
and
2
, operations of stopping up and sealing the liquid crystal injection portions
6
are performed.
The operations are performed as follows. That is, as shown in
FIG. 10
of a prior art method, the pairs of substrates
1
and
2
subjected to the liquid crystal drawing operation are uprightly arrayed such that the liquid crystal injection portions
6
face the upper side. The distal end of a resin injection nozzle
12
is sequentially positioned at the openings of the liquid crystal injection portions
6
illuminated with a lighting tool
13
, and a resin is injected from the distal end of the resin injection nozzle
12
. A resin sticking out of each of the injection portions
6
is wiped off, and the resin of the injection portion
6
is solidified to form the sealed portion
7
.
However, since the operation of injecting the resin into the liquid crystal injection portion
6
of each pair of substrates
1
and
2
by using the resin injection nozzle
12
is an important operation which may cause a liquid crystal to leak when erroneous injection such as offsetting of an injection position, the operation must be strictly performed. When the liquid crystal injection portion
6
is illuminated with the lighting tool
13
, there is a problem in that the position of the liquid crystal injection portion
6
cannot be easily detected.
This problem is caused by the following reason. That is, when the substrates
1
and
2
are used in a reflection type liquid crystal display device, the reflective film
8
is formed on the entire surface of the rear surface side of the substrates
2
. Because the liquid crystal injection portion
6
of another pair of substrates
1
and
2
located behind the substrate
2
in an arrangement which pairs of substrates
1
and
2
are arrayed as shown in
FIG. 10
, the liquid crystal injection portion
6
with the reflective layer
8
is shielded by the substrate
2
on the front side. For this reason, an operator cannot easily recognize a precise position of the liquid crystal injection portion
6
. Position check must be performed by an image analyzer such as a television camera. All the positions of the liquid crystal injection portions
6
of the pairs of substrates
1
and
2
in an array state cannot be checked from the outside because each reflective layer
8
on the front side shields each liquid crystal injection portion
6
on the rear side. In addition, even if injection positions can be precisely recognized, filing of a resin may not be satisfactorily performed depending on an injection state of the resin. An amount of injection may be so excessive that the resin sticking out of the liquid crystal injection portion
6
may be adhered to the peripheral portion of the liquid crystal injection portion
6
.
Uneven injection may be caused when a liquid crystal is injected into the pairs of substrates
1
and
2
as shown in FIG.
9
. In a vacuum atmosphere, it is difficult to completely recognize and check whether the liquid crystal is filled into the pairs of substrates
1
and
2
. Whether the liquid crystal injection process is completed is typically recognized by a time parameter of a pressure-reduction time when a vacuum atmosphere is made, and when a predetermined period of time has elapsed, completion of the injection is determined. However, if defective liquid crystal injection occurs for some reason, substrates
1
and
2
in which the defective liquid crystal injection occurs cannot be detected in the resin sealing process shown in FIG.
10
. Therefore, a defective product may be manufactured.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above circumstances, and has as its object to provide a liquid crystal display device which, when a liquid crystal injection portion is sealed and stopped up with a resin after a liquid crystal injection operation, makes it possible to easily and precisely perform the operation and makes it possible to easily detect defective liquid crystal injection.
In order to solve the above problems, the present invention provides a liquid crystal display device comprising one substrate on which a metal reflective film is formed, the other substrate arranged opposite to the substrate, a sealing material, interposed between the pair of substrates, for surrounding, together with the substrates, a liquid crystal injection space formed between the substrates, and a liquid crystal sealed into the liquid crystal injection space, characterized in that a liquid crystal injection portion is formed
Date Takashi
Hoshino Toshiaki
Alps Electric Co. ,Ltd.
Kim Robert H.
Qi Mike
LandOfFree
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