Etching a substrate: processes – Forming or treating article containing a liquid crystal...
Patent
1999-08-27
2000-11-07
Gulakowski, Randy
Etching a substrate: processes
Forming or treating article containing a liquid crystal...
216 51, 216 52, 216 67, G02F 11333
Patent
active
061431893
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal cell, and on a method for manufacturing panels.
BACKGROUND INFORMATION
A method for manufacturing a liquid crystal cells is described in the article "Simplest Process Color TFT LCDs." The liquid crystal cell consists of two glass panels which are adhesively bonded together at a small spacing from one another which is maintained by spacers. The liquid crystal is located between these glass panels. One of the glass panels is coated on the inside of the liquid crystal cell with one or more photoemulsion layers.
It is also know in the art, although a color pigment coating is used instead of the photoemulsion, to manufacture several liquid crystal cells on a large glass panel, which at the end of the manufacturing process is scored and broken.
Breaking the glass panel coated with the photoemulsion is problematic, however, which complicates mass production of liquid crystal cells having a photoemulsion coating. The photoemulsion usually consists of a relatively thick (for example 16 micrometers) gelatin layer which detaches over large areas when the glass is broken. Since gelatin is moreover moisture-sensitive, cutting using a water jet is also impossible.
SUMMARY OF THE INVENTION
The method according to the present invention has the advantage that several gelatin-coated glass panels can be manufactured in a single process pass. On the one hand, production is thereby made simpler and also cheaper, and on the other hand, fluctuations in production quality are also reduced. The method according to the present invention makes possible the manufacture of liquid crystal cells with color filters made of photoemulsion, or also with black matrix made of photoemulsion, in large volumes and thus more economically.
For example, production of the preset break point by scoring is particularly advantageous because computer numerically controlled machines which already exist can be utilized for this separation method.
Glass advantageously combines favorable mechanical properties, since it can be parted by scoring and breaking, and favorable optical properties, since it can be manufactured with very low absorption coefficients. In addition, glass is chemically inert and can be equipped with a plurality of coatings.
Sputtering of the protective layer represents a relatively economical thin-film technique, and therefore leads to a further decrease in manufacturing cost.
The use of indium-tin oxide as the protective layer advantageously yields a layer which, in addition to its protective function, is both electrically conductive and optically transparent. The protective layer can thus perform a dual function as protective layer and electrode.
It is particularly advantageous to ablate the gelatin layer with the aid of reactive ion etching using O.sub.2 --Ar--SF.sub.6, since this process step on the one hand guarantees thorough removal of the gelatin in the exposed regions, but at the same time does not also affect the edge region of the gelatin that is not intended to be ablated. Very sharp edges without underetching are thus produced.
Lastly, it is advantageous to apply an orientation layer onto the protective layer, since a liquid crystal to be introduced into the liquid crystal cell thereby receives a precisely defined preferred direction.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1-6 show steps of a method for manufacturing a gelatin-coated panel according to the present invention.
FIG. 1 depicts a panel, for example glass.
FIG. 2 depicts formation of a gelatin layer.
FIG. 3 depicts formation of a mask on the gelatin layer and then deposition of ITO.
FIG. 4 depicts removal of the mask and then etching of the gelatin layer using ITO as an etch mask.
FIG. 5 depicts the resulting etched panel.
FIG. 6 depicts dividing the panel into individual segments.
FIG. 7 shows a liquid crystal cell.
FIGS. 8-10 show steps of a method for manufacturing a liquid crystal cell according to the present invention.
FIG. 8 depicts a panel with s
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**Prolonge et al., "Simplest Process Color TFT-LCDs", Asia Display '95, pp. 697-700, 1995.
Glueck Joachim
Kaefer Stefan
Alanko Anita
Gulakowski Randy
Robert & Bosch GmbH
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