Computer graphics processing and selective visual display system – Computer graphic processing system – Interface
Reexamination Certificate
1998-05-27
2001-06-26
Tung, Kee M. (Department: 2671)
Computer graphics processing and selective visual display system
Computer graphic processing system
Interface
C345S519000, C345S519000
Reexamination Certificate
active
06252613
ABSTRACT:
FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
The present invention concerns a device for addressing a matrix screen such as a screen of the LCD or plasma type.
The display surfaces of such screens generally have a plurality of subpixels P(i,j) representing one of the primary colours R, G or B and addressed through a crossed network of N horizontal rows and M vertical columns, each subpixel receiving, through a switch which connects it to the adjacent column, during the addressing phase (line time), a sampled video signal.
The spatial resolution of such screens depends on the number and mode of combinations of addressable subpixels used to produce displayable pixels, whose successive sequences constitute the video rows and columns of the image to be displayed.
FIG. 1
illustrates a known mode of combining subpixels, referred to as L mode, use for addressing an orthogonal screen and consisting of producing a displayable pixel by combining three subpixels R, G and B situated on the same row. In this case, the horizontal resolution, denoted Hr, is equal to M/3, and is small compared with the vertical resolution, denoted Hv, whose value is equal to N. This is because the design of a VGA screen of 480 rows and 640 columns using the L combination mode requires a number of columns M equal to 640*3=1920, and a number of rows N equal to 480. In addition, in order to respect the format of the image, this combination mode requires a high number of subpixels, which appreciably increases the cost of the screen.
Moreover, insofar as matrix screens can be addressed only in progressive mode, the combination mode described in
FIG. 1
requires the use of an algorithm for adapting the screen to a source of interlaced images.
FIGS. 2 and 3
illustrate respectively a first variant and a second variant of a second known mode of combining subpixels, referred to as Delta mode, used for addressing a screen of the DELTA type. Like the L mode, a displayable pixel is obtained by combining three subpixels R, G and B situated on the same horizontal row. However, in the first variant of the Delta mode, depicted in
FIG. 2
, two successive rows are offset horizontally with respect to each other by half a subpixel, whilst in the second variant, depicted in
FIG. 3
, two successive rows are offset horizontally with respect to each other by one and a half subpixels. As a result, in the first case, a column of displayable pixels has a width equal to three and a half times the width of a subpixel whilst in the second case a column of displayable pixels has a width equal to four and a half times that of a subpixel. In the first case, the horizontal resolution is reduced in a proportion of three and a half times with respect to the vertical resolution, whilst in the second case the horizontal resolution is reduced in a proportion of four and a half times with respect to the vertical resolution.
SUMMARY OF THE INVENTION
The aim of the invention is to produce a device for addressing a matrix screen enabling the horizontal resolution to be improved without excessively degrading the vertical resolution.
The device according to the invention has a memory stage
70
and
198
receiving, via a demultiplexing stage
220
, a plurality of sequences of digital data representing the previously stored luminance video signals and delivering the said luminance video signals to a multiplexing stage
230
designed to select a sequence of digital data corresponding to a given combination of subpixels from amongst the plurality of sequences of digital data previously stored in the said memory stage
70
and
198
.
Thus the device according to the invention enables a combination of subpixels to be selected making it possible to obtain a better compromise between the vertical resolution and horizontal resolution whatever the type of screen used.
REFERENCES:
patent: 4792856 (1988-12-01), Shiratsuchi
patent: 4985698 (1991-01-01), Mano et al.
patent: 5053863 (1991-10-01), Ohtsuka
patent: 5444497 (1995-08-01), Takeuchi
patent: 5841480 (1998-11-01), Rhodes
patent: 3634092 A1 (1988-04-01), None
patent: 0368572 (1990-05-01), None
patent: 0428324 (1991-05-01), None
Borel Thierry
Dupont Antoine
Garnier Stéphane
Le Ludec Benoît
Lehureau Jean-Claude
Fried Harvey D.
Henig Sammy S.
Thomson Multimedia S.A.
Tripoli Joseph S.
Tung Kee M.
LandOfFree
Matrix display addressing device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Matrix display addressing device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Matrix display addressing device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2461191