Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2002-06-26
2004-10-26
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C430S007000
Reexamination Certificate
active
06809784
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color filter and a method for manufacturing the color filter, more particularly, to a color filter and a method for manufacturing the color filter of reflective type LCD.
2. Description of the Related Art
Referring to
FIG. 1
, the conventional color filter
1
comprises black frame (BF)
11
, a red pixel array (R)
12
, a green pixel array (G)
13
, a blue pixel array (B)
14
and a substrate
15
. The color filter
1
for reflective type LCD is manufactured by dry film technology. Firstly, the black frame
11
is formed on the substrate
15
. Then in sequence, the red pixel array
12
, the green pixel array
13
and the blue pixel array
14
are formed on the substrate
15
. The black frame
11
, the red pixel array
12
, the green pixel array
13
and the blue pixel array
14
must be formed on the substrate
15
by utilizing photomasks, exposure and development process to form the pattern of each pixel array on the substrate
15
. Therefore, four photomasks are needed in the process of manufacturing the color filter
1
. However, the photomask is expensive. If the number of the photomask can be lessened, the cost of the color filter will be reduced.
The red pixel array
12
is adjacent to the green pixel array
13
and the blue pixel array
14
in sequence. Because of the limit of the positioning precision of the exposure instrument, there are protrusions
16
on the adjacent area. For example, when the green pixel array
13
is formed on the substrate, the protrusion
16
is formed on the adjacent area, covering the partial edge of the red pixel array
12
. Similarly, the adjacent areas between the blue pixel array
14
and the red pixel array
12
and between the blue pixel array
14
and the green pixel array
13
have the protrusions. The protrusion may easily interfere the display performance of the LCD product.
Furthermore, when the red pixel array
12
, the green pixel array
13
and the blue pixel array
14
are formed on the substrate
15
, the pixel array will have pinhole, if there are particles in the pixel array. The pinhole will be a white spot in the screen of the LCD, and will be a defect of the LCD product.
Therefore, it is necessary to provide an innovative and progressive color filter and method for manufacturing the same so as to solve the above problem.
SUMMARY OF THE INVENTION
One objective of the present invention is to provide a method for manufacturing a color filter. The method utilizes the dry film technology, photomasks, exposure and development process to form the black frame, the red pixel array and the green pixel array on the substrate. The blue pixel array is formed on the substrate by utilizing a back mask, exposure process from the backside of the substrate and development process. Therefore, the red pixel array and the green pixel array on the substrate can cut the UV exposure from backside. In the exposure process, only the blue pixel array in a recess area is exposed to the UV light. After the development process, the blue pixel array is formed on the substrate. Because the photomask is more expensive than the back mask, the method of the invention can reduce the cost of the LCD product by using a back mask instead of a photomask.
According to the method of the invention, the red pixel array and the green pixel array provides photomask function to shield UV from the back side of the substrate such that the blue pixel array is formed on the substrate. The problem of positioning precision and the error caused by the photomask on the prior art can be solved. Therefore, both a first adjacent area between the blue pixel array and the green pixel array and a second adjacent area between the blue pixel array and the red pixel array have flat surface without protrusions so as to have better quality.
Furthermore, according to the method of the invention, the blue pixel array is formed on the substrate by a back mask and exposure from backside. Therefore, the blue film can fill the pinhole caused by the particles on the red pixel array and the green pixel array so that the LCD product does not have the white spot caused by the pinhole. The yield of the LCD product can be improved.
REFERENCES:
patent: 5101289 (1992-03-01), Takao et al.
patent: 5212575 (1993-05-01), Kojima et al.
patent: 6392729 (2002-05-01), Izumi et al.
Ho Chiu-Hui
Hsu Jui-Mei
Pai Chia-Hui
Chi Mei Optoelectronics Corp.
Kim Richard H
Kim Robert H.
Senniger Powers
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