Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1999-09-15
2001-11-06
Liang, Regina (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S182000
Reexamination Certificate
active
06313816
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a display apparatus such that, when forming a screen by arranging emitters like a mosaic display, if there is a portion of a different light emission wavelength that deteriorates uniformity of the screen, the color of the whole screen can be held uniform by performing a correction so that each of three primary colors of the color light emission has a same chromaticity point.
2. Description of the Related Art
For example, in the case where one pixel is constructed by a trio (hereinafter referred to as an RGB trio) of light emitting diodes (hereinafter referred to as LEDs) of three primary colors of R, G, and B and a mosaic display (large video display apparatus) is formed by arranging a number of pixels, it is necessary to select and use the LEDs such that the luminous intensity and light emission wavelength of the LED lie within a certain standard (hereinafter referred to as a rank). This is because it is necessary to avoid a problem of a color variation due to a variation in characteristics of the LEDs.
As such a variation, there are
1. variation in luminous and intensity (luminance)
2. variation in light emission wavelength (chromaticity)
In case of constructing one pixel by the RGB trio, the variation in luminous intensity deteriorates the uniformity of the luminance and the uniformity of the chromaticity of the halftone color. The variation in light emission wavelength deteriorates the uniformity of the chromaticity of the halftone color and three primary colors. If the LEDs having a variation in characteristics as mentioned above are used at random without selecting, a color variation due to a difference of the light emission wavelengths is conspicuous and the picture quality deteriorates.
However, in case of using the LEDs of the same rank for one screen, it is necessary to prepare the LEDs for maintenance every rank when considering the productivity of every screen and performing a service maintenance. There is, consequently, a problem of causing excessive costs for maintenance and the like as a whole.
In JP-A-10-26959, there has been disclosed a method such that both an amplitude and a DC level of a video signal of at least one of the R, G, and B colors are corrected by stored luminance correction data in accordance with a position of a screen in order to correct a luminance variation of each monochromatic color of R, G, and B due to the positions on an LED array which is caused by a variation in luminous intensity (luminance) of every element of an LED and a color variation due to the overlap of them. As mentioned above, the method such that the luminance variation due to the variation in luminous intensity (luminance) and the color variation due to the overlap of them are corrected by matching the luminance levels of the pixels of each monochromatic color has already been known.
According to the method disclosed in this literature, however, although the luminance variation due to the variation in luminous intensity (luminance) can be solved, there is a problem such that a color variation which is caused due to the variation in light emission wavelength (chromaticity) cannot be corrected.
OBJECTS AND SUMMARY OF THE INVENTION
It is, therefore, an object of the invention to provide a display apparatus which can keep expression colors (hereinafter, referred to as CIE tristimulus values) of each pixel constructing the whole screen uniform without selecting LEDs.
There is provided a display apparatus for displaying by a set of trios constructed by emitters of three primary colors on the basis of an input signal, wherein the apparatus has chromaticity correcting means for adding, to data of one color in the trio, data obtained by multiplying data of the other one or two colors in the trio by a pre-obtained chromaticity correction coefficient when each of the emitters of three primary colors is driven.
When a mosaic display in which one pixel is constructed from the emitters (RGB trio) of three primary colors and which is constructed by a set of a plurality of pixels is driven, the chromaticity correction coefficient which has previously been obtained and stored in a chromaticity correction data memory for light emission data that is supplied is corrected by the other one or two colors in accordance with a variation in characteristics of each emitter (LED). Thus, since the chromaticity points of the three primary colors can be matched, there is no need to perform a rank management of the light emission wavelengths of the emitters. The excessive costs for the improvement of the productivity of products, the service performance, the rank management of product stocks, and the like can be reduced and the products of the uniform image display quality can be stably manufactured.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.
REFERENCES:
patent: 5384601 (1995-01-01), Yamashita et al.
patent: 5446504 (1995-08-01), Wada
patent: 5764216 (1998-06-01), Tanaka et al.
patent: 5949496 (1999-09-01), Kim
Kojima Toshihisa
Nakagawa Hideaki
Okamoto Eizo
Liang Regina
Maioli Jay H.
Sony Corporation
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