Optical: systems and elements – Glare or unwanted light reduction
Reexamination Certificate
2000-05-24
2002-07-16
Sikder, Mohammad (Department: 2872)
Optical: systems and elements
Glare or unwanted light reduction
C359S602000, C359S608000, C359S229000
Reexamination Certificate
active
06419366
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image display device, and more particularly, to an image display device which comprises an antiglare surface having unevenness and pixels having a pixel pitch of about 10 to about 100 &mgr;m.
2. Description of the Related Art
With regard to image display devices, density of displayed image has recently increased year by year even in a small image display device having a small display area. For example, as for small image display devices having a display screen of 2.5 inch size, image display devices having 180,000 or more pixels have been developed as well as conventional ones having about 80,000 pixels. As for image display devices performing a color display, a pixel pitch (a) of image display devices having about 180,000 pixels is about 60 &mgr;m, while the pixel pitch (a) of image display devices having about 80,000 pixels is generally about 80 to about 100 &mgr;m. Here, a pixel pitch (a) is a distance between adjacent pixels and refers to the minimum one of the longitudinal and lateral dimensions of individual pixels forming an image. In the case of image display devices performing a color display, the pixel pitch (a) represents the minimum one of the longitudinal and lateral dimensions (a and b) of individual pixels (
7
R,
7
G and
7
B) that respectively indicate R(red), G(green), or B(blue) (See, FIG.
1
).
On the other hand, an image display device which has an antiglare surface having unevenness on the utmost surface thereof has been known for preventing the surrounding scenery from showing up in the screen thereof. An image display device possessing such an antiglare surface has advantages in that visibility of displayed images is good since the surrounding scenery showing up on the utmost surface thereof is diffused and reflected by the unevenness of the utmost surface, and is not recognized as an image.
However, when the antiglare surface having unevenness is disposed on the utmost surface in an image display device having a pixel pitch (a) of smaller than about 100 &mgr;m, a so-called “glittering (scintillation)” is generated in some cases, thereby sometimes leading to decrease in clearness of images. Such “glittering” lowers the visibility of displayed images.
SUMMARY AND OBJECTS OF THE INVENTION
The inventors of the present invention have devoted intensive efforts to restrain the “glittering” generated in image display devices which comprises an antiglare surface having unevenness and pixels having a pixel pitch (a) of smaller than about 100 &mgr;m. As a result, the inventors of the present invention have found that in image display devices which comprises pixels having such a pixel pitch (a), the generation of “glittering” can be restrained when a ratio of an average spacing of roughness peak (Sm) of the unevenness on the antiglare surface to the pixel pitch (a) is a specific value or smaller. Thus the inventors have accomplished the present invention.
The present invention provides an image display device which comprises an antiglare surface having unevenness and pixels having a minimum pixel pitch (a) of from about 10 to about 100 &mgr;m, wherein a ratio (Sm/a) of an average spacing of roughness peak (Sm) of the unevenness to the minimum pixel pitch (a) is about 0.4 or smaller.
REFERENCES:
patent: 5774303 (1998-06-01), Teng et al.
patent: 5847795 (1998-12-01), Satoh et al.
patent: 6077472 (2000-06-01), Kataoka et al.
patent: 6120152 (2000-09-01), Nakayama et al.
patent: 63-298201 (1988-12-01), None
patent: 9-193332 (1997-07-01), None
patent: 9-193333 (1997-07-01), None
patent: 95/31737 (1995-11-01), None
Sikder Mohammad
Sughrue Mion Zinn Macpeak & Seas, PLLC
Sumitomo Chemical Company Limited
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