Liquid crystal cells – elements and systems – Particular structure – Particular illumination
Reexamination Certificate
2002-05-13
2002-11-12
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Particular illumination
C349S112000, C362S035000
Reexamination Certificate
active
06480246
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color image display device for displaying a color image.
2. Description of the Related Art
Hitherto, in a color image display device for displaying a color image, mixed colors are represented in such a manner that pixels of three primary colors of R (red), G (green) and B (blue) are closely disposed and the pixels are miniaturized. However, when there are displayed a white character of black in a background and reversely a black character of white in a background, it happens that color bleeding occurs on a boundary portion between the background and the characters, because the pixels of three primary colors of R, G and B are independently of one another.
Resolution of a color image display device, which now comes into wide use as a computer use, is generally 1024×768 pixels or so, or about one and a half times as much as 1024×768 pixels or so. With such an extent of resolution the color bleeding is not almost conspicuous. Recently, however, resolution of a color image display device is enhanced and there has been developed a high class of display device with 4000 pixels in long side. It often happens that such a high resolution of color image display device is used in a medical field and a field of the proof use for printing, and in such utilization fields, there is needed a higher definition of color image display device. Particularly, in the printing field, it often happens that black characters are often used in white background, and thus a quality of color representation of characters is a very important element.
Generally, in a color display device, it often happens that pixels of RGB are regularly arranged, for example, R, G, B, R, G, B, . . .
FIG. 2
is a view showing a pixel arrangement pattern of a conventional color image display device.
FIG. 2
shows a state that pixels of RGB are regularly arranged in the arrow X direction, like, R, G, B, R, G, B, . . . , and are regularly arranged in the arrow Y direction, like, R, R, R, . . . , G, G, G, . . . , B, B, B, . . . In the event that a display of white characters is performed using a color image display having such a pixel arrangement pattern, for example, there is provided such a display that the left end of a non-emissive area
41
expressed by hatched lines in
FIG. 2
is subjected to edging of blue owing to an effect of light emission of B pixels
42
a
of the right end of a character display area
42
at the left side adjacent to the non-emissive area
41
. Likely, there is provided such a display that the right end of the non-emissive area
41
is subjected to edging of red owing to an effect of light emission of R pixels
43
a
of the left end of the character display area
43
at the right side adjacent to the non-emissive area
41
. Those regular color bleedings are conspicuous, and thus this is not suitable for the utilization field requiring a strict color representation.
In order to reduce the color bleeding as mentioned above, there is proposed a color image display device in which RGB pixels are arranged in such a manner that RGB pixels are shifted for each line one by one in pixel. In this case, however, there will occur a boundary line of a color bleeding in a slanting direction, and thus this is also conspicuous. Further, there is also proposed a color image display device in which three pixels of RGB are gathered as a triangle to provide pixel units, and the pixel units are regularly arranged. However, also in this case, there will occur a boundary line of a color bleeding in a slanting direction.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a color image display device capable of preventing occurrence of color bleeding.
To achieve the above-mentioned object, the present invention provides a color image display device wherein a number of pixel units, each consisting of emitters for emitting color lights of red, green and blue, are arranged on a two-dimensional basis, and control of turn on of the emitters constituting a number of pixel units displays a color image, said color image display device comprising:
optical diffusive layers covering fronts of the associated emitters, respectively, said optical diffusive layers being mutually separated for each of the pixel units.
It is noted that the above-mentioned emitters include not only ones emitting color lights of red, green and blue, but also ones in which a color filter is mounted on a liquid crystal and a color filter is mounted on a white color light emitting pixel.
REFERENCES:
patent: 4386826 (1983-06-01), Stolov
patent: 5504602 (1996-04-01), Farmer
patent: 5825442 (1998-10-01), Yoneda et al.
patent: 6-160844 (1994-06-01), None
patent: 11-295729 (1999-10-01), None
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