EP0653740A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Controlling the gray scale of plasma display devices
Assignee: Fujitsu Ltd
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Filing: 1994-01-31
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Granted: —
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Expires: 2014-01-31
Abstract
Abstract A method of controlling the gray scale of a plasma display device has a forming step of forming a frame for an image by a plurality of subframes each having a different brightness, a setting step of setting the number of sustain emissions of the each subframe individually for each subframe, and a displaying step of displaying the image on the plasma display device by a gray scale display having a specific brightness. The number of sustain emissions in each subframe is set individually by the individual subframe, and this can establish a linear relation between the gray level and the corresponding brightness. Therefore, an enhancement of display quality of the plasma display device can be realized.
Inventors
- 👤 Keishin C/O Fujitsu Limited Nagaoka
- 👤 Masaya C/O Fujitsu Limited Tajima
- 👤 Yoshimasa C/O Fujitsu Limited Awata
- 👤 Yoshikazu C/O Fujitsu Limited Kanazawa
- 👤 Toshio C/O Fujitsu Limited Ueda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 00:42
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/2007; G09G3/2018; G09G3/2022; G09G3/2029; G09G3/22; G09G3/28; G09G3/288; G09G3/291; G09G3/293; G09G3/2932; G09G3/2935; G09G3/294; G09G3/2946; G09G3/298; G09G2320/00; G09G2320/02; G09G2320/0228; G09G2320/0271; G09G2320/0276; G09G2320/04; G09G2320/043; G09G2320/046; G09G2330/00; G09G2330/02; G09G2330/021; G09G2360/00; G09G2360/14; G09G2360/145; G09G3/292; G09G3/2927
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
70 words
A method of controlling the gray scale of a plasma display device, characterized in that said method comprises the steps of: forming a frame for an image by a plurality of subframes each having a different brightness; setting the number of sustain emissions of said each subframe individually for said each subframe; and displaying the image on said plasma display device by a gray scale display having a specific brightness.
Claim 2
Dependent Claim
31 words
A method of controlling the gray scale of a plasma display device as claimed in claim 1, wherein said plasma display device is a three-electrode surface discharge AC plasma display device.
Claim 3
Dependent Claim
86 words
A method of controlling the gray scale of a plasma display device as claimed in claim 2, wherein said three-electrode surface discharge AC plasma display device comprises: first and second electrodes (7, 8) arranged in parallel with each other; and third electrodes (3) orthogonal to said first and second electrodes (7, 8), said first electrode (7) being commonly connected together, and said second electrodes (8) being arranged for display lines, respectively, wherein said display device has a surface discharge structure employing wall charges as memory media.
Claim 4
Dependent Claim
156 words
A method of controlling the gray scale of a plasma display device as claimed in claim 3, wherein said three-electrode surface discharge AC plasma display device further comprises: a first substrate (2), and said first and second electrodes (7, 8) being arranged in parallel with each other on said first substrate (2) and paired for respective display lines; a second substrate (1) spaced apart from and facing said first substrate (2), and said third electrodes (3) being arranged on said second substrate (1) away from and orthogonal to said first and second electrodes (7, 8); a wall charge accumulating dielectric layer (6) covering the surfaces of said first and second electrodes (7, 8); a phosphor (5) formed over said second substrate (1); a discharge gas sealed in a cavity defined between said first and second substrates (2, 1); and cells formed at intersections where said first and second electrodes (7, 8) cross said third electrodes (3).
Claim 5
Independent Claim
83 words
A method of controlling the gray scale of a plasma display device as claimed in any one of the preceding claims, wherein the number of sustain emissions of said each subframe is so calculated, on the basis of actually measured data of the brightness with respect to the numbers of sustain emissions, that the brightness obtained by the first subframe having an arbitrary brightness is twice the brightness obtained by the second subframe having a brightness next to that of said first subframe.
Claim 6
Independent Claim
37 words
A method of controlling the gray scale of a plasma display device as claimed in any one of the preceding claims, wherein the number of sustain emissions in said each subframe is set in an anti-geometrical progression.
Claim 7
Independent Claim
86 words
A method of controlling the gray scale of a plasma display device as claimed in any one of the preceding claims, wherein the number of sustain emissions of said each subframe is so calculated, on the basis of actually measured data of the brightness with respect to the numbers of sustain emissions, that the sum of the squares of errors with the ideal values in said each gray level becomes minimum, in order to make the relation between the gray level and the corresponding brightness linear.
Claim 8
Independent Claim
87 words
A method of controlling the gray scale of a plasma display device as claimed in any one of the preceding claims, wherein the number of sustain emissions of said each subframe is so calculated, on the basis of actually measured data of the brightness with respect to the numbers of sustain emissions, that the sum of the absolute values of errors with the ideal values in said each gray level becomes minimum, in order to make the relation between the gray level and the corresponding brightness linear.
Claim 9
Dependent Claim
58 words
A method of controlling the gray scale of a plasma display device as claimed in claim 7 or 8, wherein the brightness of the second subframe having next larger gray level than that of said first subframe does not exceed the brightness of said first subframe, for the brightness of the first subframe having said arbitrary gray level.
Claim 10
Dependent Claim
54 words
A method of controlling the gray scale of a plasma display device as claimed in claim 7 or 8, wherein the sum of the numbers of sustain emissions of one or two subframes in said plurality of subframes, or the sum of the numbers of sustain emissions of two or three subframes is specified.
Claim 11
Dependent Claim
37 words
A method of controlling the gray scale of a plasma display device as claimed in claim 7 or 8, wherein the brightness of the subframe having the maximum gray level is specified in said plurality of subframes.
Claim 12
Dependent Claim
169 words
A three-electrode surface-discharge AC plasma display device comprising: first and second electrodes (7, 8) arranged in parallel with each other; and third electrodes (3) orthogonal to said first and second electrodes (7, 8), said first electrode (7) being commonly connected together, and said second electrodes (8) being arranged for display lines, respectively, characterized in that said display has a surface discharge structure employing wall charges as memory media, said plasma display device is driven separating address periods in which display data are written in the whole screen by forming wall charge, said wall charge is necessary for sustain discharge according to said display data from sustain discharge periods in which sustain discharge for light emission is repeated, one frame forming an image is constituted by a plurality of subframes each having a different brightness, the number of sustain emissions of said each subframe is individually set for said each subframe, and the image is displayed on said plasma display device by a gray scale display having a predetermined brightness.
Claim 13
Dependent Claim
147 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 12, wherein said plasma display device further comprises: a first substrate (2), and said first and second electrodes (7, 8) being arranged in parallel with each other on said first substrate (2) and paired for respective display lines; a second substrate (1) spaced apart from and facing said first substrate (2), and said third electrodes (3) being arranged on said second substrate (1) away from and orthogonal to said first and second electrodes (7, 8); a wall charge accumulating dielectric layer (6) covering the surfaces of said first and second electrodes (7, 8); a phosphor (5) formed over said second substrate (1); a discharge gas sealed in a cavity defined between said first and second substrates (2, 1); and cells formed at intersections where said first and second electrodes (7, 8) cross said third electrodes (3).
Claim 14
Dependent Claim
59 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 12 or 13, wherein said plasma display device further comprises a memory means (55) for setting and storing the number of sustain emissions in each subframe, and information on the number of sustain emissions in said each subframe is read at any time from said memory means (55).
Claim 15
Dependent Claim
60 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 14, wherein said memory means is constituted by a vacant area of a driving wave-form memory device (55) in said plasma display device, and the information on the number of sustain emissions in said each subframe is set in the vacant area of said driving wave-form memory device (55).
Claim 16
Dependent Claim
54 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 14, wherein said plasma display device further comprises a brightness controller (51) for adjusting the brightness, and said brightness controller (51) selects one piece from the information on the number of sustain emissions in said each subframe set in said memory means (55).
Claim 17
Dependent Claim
59 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 14, wherein the number of sustain emissions in said each subframe is set as a plurality of combinations in said memory means (55), and an arbitrary one of said plurality of combinations is selected by means of selection signals supplied from the outside of said plasma display device.
Claim 18
Dependent Claim
94 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 14, wherein said plasma display device further comprises a consumed current controller means (44) for controlling and keeping the consumed current below a predetermined value, the number of sustain emissions in said each subframe is set as a plurality of combinations in said memory means (55), an arbitrary one of said plurality of combinations is selected in response to the output from said consumed current controller means (44), and thereby the power consumption is kept constant regardless of the change of display rate.
Claim 19
Dependent Claim
35 words
A three-electrode surface-discharge AC plasma display device as claimed in claim 14, wherein the information on the number of sustain emissions in said each subframe is supplied from the outside of said plasma display device.
References Cited (Backward Citations)
No citation records indexed.
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