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US5943032A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for controlling the gray scale of plasma display device

Assignee: Hitachi Ltd
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Filing: 1995-06-07
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Granted: 1999-08-24
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Expires: 2015-06-07
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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 each subframe in an anti-geometrical progression corresponding to the brightness of 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 each subframe, and this establishes 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 Nagaoka
  • 👤 Masaya Tajima
  • 👤 Yoshimasa Awata
  • 👤 Yoshikazu Kanazawa
  • 👤 Toshio Ueda

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 20:31
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/2007; G09G3/2018; G09G3/2022; G09G3/22; G09G3/28; G09G3/288; G09G3/291; G09G3/294; G09G3/2946; G09G2320/00; G09G2320/02; G09G2320/0271; G09G2320/06; G09G2320/0626; G09G2330/00; G09G2330/02; G09G2330/021; G09G2360/00; G09G2360/14; G09G2360/145; G09G2360/16

Claims Analysis

Total Claims: 31
Claim 1
Independent Claim 113 words
A method of controlling the gray scale of a plasma display device, wherein said method comprises the steps of: forming a frame for an image by a plurality of subframes each having a specific weight value; calculating a ratio of brightnesses of said plurality of subframes so as to substantially correspond with a ratio of the weight values of said plurality of subframes, wherein a ratio of numbers of sustain emissions of said plurality of subframes does not equal the ratio of the weight values of said plurality of subframes; and displaying the image on said plasma display device by optionally combining said subframes each having the calculated number of the sustain emissions.
Claim 2
Independent Claim 113 words
A method of controlling the gray scale of a plasma display device, wherein said method comprises the steps of: forming a frame for an image by a plurality of subframes each having a specific weight value; calculating a ratio of brightnesses of said plurality of subframes so as to substantially correspond with a ratio of the weight values of said plurality of subframes, wherein a ratio of numbers of sustain emissions of said plurality of subframes does not equal the ratio of the weight values of said plurality of subframes; and displaying the image on said plasma display device by optionally combining said subframes each having the calculated number of the sustain emissions.
Claim 3
Dependent Claim 69 words
A method of controlling the gray scale of a plasma display device as claimed in claim 1, wherein the number of sustain emissions of said each subframe is so calculated, that the brightness obtained by one subframe of said plurality of subframes having an arbitrary brightness is twice the brightness obtained by another subframe of said plurality of subframes having a brightness next to that of said one subframe.
Claim 4
Dependent Claim 154 words
A plasma display device comprising at least one pair of electrodes for carrying out a discharge operation, wherein: said plasma display device is driven separating address periods in which display data are written in the screen, said display data is necessary for sustain discharge 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 specific weight value, a ratio of brightnesses of said plurality of subframes is calculated so as to substantially correspond with a ratio of the weight values of said plurality of subframes, wherein a ratio of numbers of sustain emissions of said plurality of subframes does not equal the ratio of the weight values of said plurality of subframes, and the image is displayed on said plasma display device by optionally combining said subframes each having the calculated number of the sustain emissions.
Claim 5
Dependent Claim 154 words
A plasma display device comprising at least one pair of electrodes for carrying out a discharge operation, wherein: said plasma display device is driven separating address periods in which display data are written in the screen, said display data is necessary for sustain discharge 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 specific weight value, a ratio of brightnesses of said plurality of subframes is calculated so as to substantially correspond with a ratio of the weight values of said plurality of subframes, wherein a ratio of numbers of sustain emissions of said plurality of subframes does not equal the ratio of the weight values of said plurality of subframes, and the image is displayed on said plasma display device by optionally combining said subframes each having the calculated number of the sustain emissions.
Claim 6
Dependent Claim 20 words
A plasma display device as claimed in claim 3, wherein said plasma display device is a three-electrode plasma display device.
Claim 7
Dependent Claim 24 words
A plasma display device as claimed in claim 4, wherein said three-electrode plasma display device is a three-electrode surface discharge AC plasma display device.
Claim 8
Dependent Claim 68 words
A plasma display device as claimed in claim 4, wherein said three-electrode plasma display device comprises: first and second electrodes arranged in parallel with each other; and third electrodes orthogonal to said first and second electrodes, said first electrode being commonly connected together, and said second electrodes being arranged for display lines, respectively, wherein said display device has a surface discharge structure employing wall charges as memory media.
Claim 9
Dependent Claim 133 words
A plasma display device as claimed in claim 6, wherein said three-electrode plasma display device further comprises: a first substrate, and said first and second electrodes being arranged in parallel with each other on said first substrate and paired for respective display lines; a second substrate spaced apart from and facing said first substrate, and said third electrodes being arranged on said second substrate away from and orthogonal to said first and second electrodes; a wall charge accumulating dielectric layer covering the surfaces of said first and second electrodes and said first substrate; a phosphor formed over said third electrodes and said second substrate; a discharge gas sealed in a cavity defined between said first and second substrates; and cells formed at intersections where said first and second electrodes cross said third electrodes.
Claim 10
Dependent Claim 20 words
A plasma display device as claimed in claim 3, wherein said plasma display device is a two-electrode plasma display device.
Claim 11
Dependent Claim 23 words
A plasma display device as claimed in claim 8, wherein said two-electrode plasma display device is a two-electrode facing-discharge AC-driven plasma display panel.
Claim 12
Dependent Claim 57 words
A plasma display device as claimed in claim 8, wherein said two-electrode plasma display device comprises: a plurality of first electrodes; and a plurality of second electrodes orthogonal to said first electrodes, and said first electrodes being arranged for display lines, respectively wherein said display device has a surface discharge structure employing wall charges as memory media.
Claim 13
Dependent Claim 116 words
A plasma display device as claimed in claim 10, wherein said two-electrode plasma display device further comprises: a first substrate, and said first electrodes being arranged in parallel on said first substrate; a second substrate spaced apart from and facing said first substrate, and said second electrodes being arranged on said second substrate away from and orthogonal to said first electrodes; a wall charge accumulating dielectric layer covering the surfaces of said first electrodes and said first substrate; a phosphor formed over said second electrodes and said second substrate; a discharge gas sealed in a cavity defined between said first and second substrates; and cells formed at intersections where said first electrodes cross said second electrodes.
Claim 14
Dependent Claim 50 words
A plasma display device as claimed in claim 3, wherein said plasma display device further comprises a memory 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.
Claim 15
Dependent Claim 54 words
A plasma display device as claimed in claim 12, wherein said memory is constituted by a vacant area of a driving wave-form memory device 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.
Claim 16
Dependent Claim 47 words
A plasma display device as claimed in claim 12, wherein said plasma display device further comprises a brightness controller for adjusting the brightness, and said brightness controller selects one piece from the information on the number of sustain emissions in said each subframe set in said memory.
Claim 17
Dependent Claim 52 words
A plasma display device as claimed in claim 12, wherein the number of sustain emissions in said each subframe is set as a plurality of combinations in said memory, and an arbitrary one of said plurality of combinations is selected by selection signals supplied from the outside of said plasma display device.
Claim 18
Dependent Claim 85 words
A plasma display device as claimed in claim 12, wherein said plasma display device further comprises a consumed current controller 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, an arbitrary one of said plurality of combinations is selected in response to the output from said consumed current controllers and thereby the power consumption is kept constant regardless of the change of display rate.
Claim 19
Dependent Claim 32 words
A plasma display device as claimed in claim 12, wherein the information on the number of sustain emissions in said each subframe is supplied from the outside of said plasma display device.
Claim 20
Independent Claim 109 words
A method of controlling the gray scale of a plasma display device, wherein said method comprises the steps of: forming a frame for an image by a plurality of subframes each having a specific weight value; and displaying the image on said plasma display device by optionally combining gray levels of said plurality of subframes, wherein a ratio of brightnesses of each gray level is calculated so as to substantially correspond with a ratio of the specific weight values of each gray level and a ratio of numbers of sustain emissions of each gray level does not equal the ratio of the specific weight values of each gray level.
Claim 21
Independent Claim 109 words
A method of controlling the gray scale of a plasma display device, wherein said method comprises the steps of: forming a frame for an image by a plurality of subframes each having a specific weight value; and displaying the image on said plasma display device by optionally combining gray levels of said plurality of subframes, wherein a ratio of brightnesses of each gray level is calculated so as to substantially correspond with a ratio of the specific weight values of each gray level and a ratio of numbers of sustain emissions of each gray level does not equal the ratio of the specific weight values of each gray level.
Claim 22
Dependent Claim 64 words
A method of controlling the gray scale of a plasma display device as claimed in claim 18, wherein the number of sustain emissions of said each subframe is so calculated, 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 23
Dependent Claim 64 words
A method of controlling the gray scale of a plasma display device as claimed in claim 19, wherein the brightness of one subframe of said plurality of subframes having next larger gray level than that of another subframe of said plurality of subframes does not exceed the brightness of said another subframe, for the brightness of said another subframe having said arbitrary gray level.
Claim 24
Dependent Claim 36 words
A method of controlling the gray scale of a plasma display device as claimed in claim 19, wherein the sum of the numbers of sustain emissions of several subframes in said plurality of subframes is specified.
Claim 25
Dependent Claim 31 words
A method of controlling the gray scale of a plasma display device as claimed in claim 19, wherein the brightness of an optional subframe is specified in said plurality of subframes.
Claim 26
Dependent Claim 65 words
A method of controlling the gray scale of a plasma display device as claimed in claim 18, wherein the number of sustain emissions of said each subframe is so calculated, 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 27
Dependent Claim 64 words
A method of controlling the gray scale of a plasma display device as claimed in claim 23, wherein the brightness of one subframe of said plurality of subframes having next larger gray level than that of another subframe of said plurality of subframes does not exceed the brightness of said another subframe, for the brightness of said another subframe having said arbitrary gray level.
Claim 28
Dependent Claim 36 words
A method of controlling the gray scale of a plasma display device as claimed in claim 23, wherein the sum of the numbers of sustain emissions of several subframes in said plurality of subframes is specified.
Claim 29
Dependent Claim 31 words
A method of controlling the gray scale of a plasma display device as claimed in claim 23, wherein the brightness of an optional subframe is specified in said plurality of subframes.
Claim 30
Dependent Claim 149 words
A plasma display device comprising at least one pair of electrodes for carrying out a discharge operation, wherein: said plasma display device is driven separating address periods in which display data are written in the screen, said display data is necessary for sustain discharge 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 specific weight value, and an image on said plasma display device is displayed by optionally combining gray levels of said plurality of subframes, wherein a ratio of brightnesses of each gray level is calculated so as to substantially correspond with a ratio of the specific weight values of each gray level, and a ratio of numbers of sustain emissions of each gray level does not equal the ratio of the specific weight values of each gray level.
Claim 31
Dependent Claim 149 words
A plasma display device comprising at least one pair of electrodes for carrying out a discharge operation, wherein: said plasma display device is driven separating address periods in which display data are written in the screen, said display data is necessary for sustain discharge 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 specific weight value, and an image on said plasma display device is displayed by optionally combining gray levels of said plurality of subframes, wherein a ratio of brightnesses of each gray level is calculated so as to substantially correspond with a ratio of the specific weight values of each gray level, and a ratio of numbers of sustain emissions of each gray level does not equal the ratio of the specific weight values of each gray level.

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2002-08-23 2003-02-22 2003-08-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2006-08-23 2007-02-22 2007-08-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2010-08-23 2011-02-22 2011-08-24 $7700.00 Window Closed / Lapsed

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