Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing... – Injecting liquid crystal
Reexamination Certificate
1999-08-03
2001-10-30
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
Injecting liquid crystal
C349S154000
Reexamination Certificate
active
06310678
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method and an apparatus for supplying a liquid crystal into a cell.
In general, a cell of a liquid crystal display exhibits a rectangular configuration. It has an injection port (first port) and an exhaust port (second port) formed in a first and a second edge portion of opposing short sides thereof, respectively. After the interior of the cell is evacuated to a predetermined degree of vacuum through the exhaust port, a pressurized liquid crystal is injected into the cell through the injection port. However, since a gap between two substrates constituting the cell is very narrow, the injected liquid crystal becomes increasingly large in pressure loss as it moves away from the injection port. For this reason, injection velocity of the liquid crystal coming through the injection port is lowered and therefore, much time is required to fill the cell with the liquid crystal, especially in the case where the cell is large in size.
Japanese Patent Unexamined Publication (Kokai) No. Hei 8-262461 discloses a method in which first, an evacuating operation is performed not only at the exhaust port but also at the injection port and when the interior of the cell reaches a predetermined degree of vacuum, the evacuating operation is switched over to a liquid crystal injecting operation at the injection port while the evacuating operation is continuously performed at the exhaust port. Although it is possible for this method to reduce the time required for evacuating the interior of the cell to a predetermined degree of vacuum, it is impossible for the method to reduce the time from the start of liquid crystal injection to the completion of liquid crystal injection.
In a method for supplying a liquid crystal disclosed in Japanese Patent Unexamined Publication (Kokai) No., Hei 9-5761, intermediate ports (third and fourth ports) are formed respectively in third and fourth edge portions of long sides of the cell orthogonal to the first and second edge portions. After the liquid crystal which has been injected into the cell from the injection port reaches the intermediate ports, a liquid crystal is also injected therein from the intermediate ports. By this, the time required for filling the liquid crystal can be reduced.
In the method disclosed in the second-mentioned Publication, no air is discharged through the intermediate ports. Therefore, the step for increasing the interior of the cell to a predetermined degree of vacuum and the following step for bringing the injected liquid crystal to the intermediate ports are substantially same as in the case where no intermediate ports are employed. Thus, time is not reduced in those steps.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method for minimizing the time required for supplying a liquid crystal into a cell.
A method according to the present invention is basically same as the conventional method in the respect that a liquid crystal is injected through a first port formed in a first edge portion and an evacuating operation is performed through a second port formed in the second edge portion. The features of the present invention reside in that at a third and a fourth port formed in the third and fourth edge portions, an evacuating operation is performed first and then, a liquid crystal injection is performed.
In one aspect of the present invention, there is provided a method including a first to third steps which are to be performed sequentially. In the first step, an evacuating operation is performed through second to fourth ports to evacuate an interior of a cell to a predetermined degree of vacuum. In the second step, a liquid crystal is injected through the first port while performing the evacuating operation through the second to fourth ports. In the third step, when or after a liquid crystal reaches the third and fourth ports, the evacuating operation is switched over to the liquid crystal injecting operation at the third and fourth ports, and the evacuating operation is continuously performed through the second port.
In another aspect of the present invention, there is also provided a method including a first and a second step which are to be performed sequentially. In the first step, an evacuating operation is performed through second to fourth ports to evacuate an interior of a cell to a predetermined degree of vacuum. In the second step, a liquid crystal injecting operation is started through a first port and simultaneously with this, the evacuating operation is switched over to a liquid crystal injecting operation at the third and fourth ports and the evacuating operation is continuously performed through the second port while performing the liquid crystal injecting operation through the first, third and fourth ports, thereby bringing the liquid crystal to the second port.
An apparatus for carrying out the method according to the present invention comprises (a) first to fourth connectors which are to be connected to the first to fourth ports, respectively, (b) liquid crystal supply means connected to the first port and for supplying a liquid crystal to an interior of the cell, (c) evacuation means connected to the second port and for evacuating the interior of the cell, and (d) connection switchover means for connecting the third and fourth ports to the evacuation means and then to the liquid crystal supply means.
REFERENCES:
patent: 3-102213 (1991-01-01), None
patent: 5-333352 (1993-12-01), None
patent: 08-262461 (1996-10-01), None
patent: 09-22019 (1997-01-01), None
patent: 09-005761 (1997-01-01), None
patent: 10-062791 (1998-03-01), None
patent: 10-142615 (1998-05-01), None
Beldex Corporation
Eugene Stephens & Associates
Parker Kenneth
Ryan Thomas B.
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