Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing... – Injecting liquid crystal
Reexamination Certificate
1998-04-15
2001-01-30
Malinowski, Walter (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
Injecting liquid crystal
C141S005000, C141S007000, C156S145000
Reexamination Certificate
active
06181408
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to the field of manufacturing tools and methods for filling liquid crystal panel displays with liquid crystal.
2. Background Description
Liquid crystal panels have become a standard for laptop computers as well as for many other types of devices requiring a display. In general the filling procedure is accomplished in a vacuum chamber by first pumping out the chamber and the panel prior to filling. However, since the spacing between the parallel plates comprising the panel are separated by only several microns, the filling process is extremely slow using present day processing techniques taking on the order of 3-5 hours, thereby limiting the throughput of panels in the manufacturing process. For certain applications such as watches and small computerized toys etc. there is no problem in filling the required space between the front and back faces of the display. However, for laptop computers where the display may have a diagonal screen dimension as large as 12 to 14 inches and an interior front to back spacing of only 5 microns, the filling process is extremely slow and tedious. In fact, the filling time is so prolonged, taking many hours, that this process step is a major cause in limiting the throughput of panel production.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved method and device for filling a liquid crystal display panel without drastically changing the overall panel manufacturing process.
The inventive method of filling includes placing the nearly completed panels, generally stacked in batches within a chamber and pumping the air out of the chamber and hence also from the space between the front and back of the panel faces. In general the top and two side edges of the panel have already been permanently affixed or sealed to one another. Once pump out has been completed the bottom panel edge which is partly unsealed or not yet affixed is brought into contact with a reservoir of liquid crystal. Following these conventional steps, the evacuated chamber is backfilled with nitrogen to produce a positive pressure on the liquid crystal, forcing it into the gap between the front and back panel faces now under vacuum. Simultaneously, the panel is put under mechanical compression to increase the rate at which filling will occur.
REFERENCES:
patent: 4106860 (1978-08-01), Kaufmann
patent: 5029623 (1991-07-01), Brosig
patent: 5568297 (1996-10-01), Tsubota et al.
patent: 5819824 (1998-10-01), Sugiura
patent: 4-147217 (1992-05-01), None
patent: 6-235896 (1994-08-01), None
Colgan Evan George
Lien Shui-Chih Alan
von Gutfeld Robert Jacob
International Business Machines - Corporation
Malinowski Walter
McGuireWoods
Percello Louis J.
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