# US 7,612,740 B2 · Plasma display and driving method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,740 B2 - Document ID: US7612740B2 - Status: Granted - Kind: B2 - Application number: 11/267,208 - Filed: 2005-11-07 - Published: 2006-03-16 - Granted: 2009-11-03 - Earliest claimed: 2004-11-05 - Assignees: Samsung SDI Co., Ltd. - Inventors: Jin-Sung Kim; Tae-Seong Kim; Jin-Ho Yang - Web page: https://patentgrep.com/patent/US7612740B2 ## CPC - G09G 3/2022: {using sub-frames} - G09G 3/2946: {by introducing variations of the frequency of sustain pulses within a frame or non-proportional variations of the number of sustain pulses in each subfield} - G09G 3/2927: {Details of initialising} - G09G 2310/066: Waveforms comprising a gently increasing or decreasing portion, e.g. ramp - G09G 2320/0238: Improving the black level - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A plasma display device includes a plasma display panel having discharge cells formed between a plurality of first electrodes and a plurality of second electrodes and a driving circuit dividing one frame into a plurality of subfields, each subfield including a reset period, an address period, and a sustain period, and applying a driving voltage to the first electrodes and the second electrodes. During a sustain period of each subfield, a sustain discharge pulse is alternately applied to the first and second electrodes for triggering a sustain discharge. A width of a last sustain discharge pulse applied to the second electrode is set to be greater than a width of other sustain discharge pulses for selected subfields. The subfields may be selected based on whether a total number of the sustain discharge pulses during the sustain period is less than a critical number of sustain discharge pulses. ## Claims ### Claim 1 A method for driving a plasma display device having a plurality of first electrodes and a plurality of second electrodes, one frame for driving the plasma display device being divided into a plurality of subfields, each subfield including a reset period, an address period, and a sustain period, the method comprising, during a sustain period of each subfield among the plurality of subfields: alternately applying a plurality of sustain discharge pulses to the first electrode and the second electrode for triggering a sustain discharge; and setting a width of a last sustain discharge pulse applied to the second electrode, the last sustain discharge pulse applied to the second electrode having a greater width than other sustain discharge pulses applied during the sustain period of the subfield when a total number of the sustain discharge pulses applied during the sustain period of the subfield is less than a predetermined number and having a width equal to the other sustain discharge pulses when the total number of the sustain discharge pulses applied during the sustain period of the subfield is greater than or equal to the predetermined number. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the predetermined number of sustain discharge pulses is fifteen. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the width of the last sustain discharge pulse applied to the second electrode is greater than 1.5 μs. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the width of the last sustain discharge pulse applied to the second electrode is greater than 3 μs. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein a last sustain discharge pulse of the sustain period of the subfield is applied to the first electrode. ### Claim 6 (depends on 5) The method as claimed in claim 5, further comprising, during a reset period immediately following the sustain period of the subfield, gradually decreasing a voltage of the first electrode after applying the last sustain discharge pulse to the first electrode during the sustain period of the subfield. ### Claim 7 (depends on 6) The method as claimed in claim 6, wherein the first electrode is a scan electrode and the second electrode is a sustain electrode. ### Claim 8 A plasma display device, comprising: a plurality of scan electrodes; a plurality of sustain electrodes; a controller dividing one frame into a plurality of subfields, each subfield including a reset period, an address period, and a sustain period, and grouping the plurality of subfields into a plurality of groups according to the number of sustain discharge pulses; and a driving circuit applying a sustain discharge pulse to the scan electrodes and the sustain electrodes with opposite polarities during a sustain period according to a control of the controller, wherein the controller sets a width of a last sustain discharge pulse applied during the sustain period to be greater than a width of other sustain discharge pulses during a sustain period of a first group among the plurality of groups, the first group having a total number of sustain discharge pulses applied during the sustain period less than a predetermined number, and to be equal to the other sustain discharge pulses during the sustain period of other groups. ### Claim 9 (depends on 8) The plasma display device as claimed in claim 8, wherein, in the sustain period of the first group, the last sustain discharge pulse applied to the sustain electrode is greater than 1.5 μs. ### Claim 10 (depends on 9) The plasma display device as claimed in claim 9, wherein a total number of the sustain discharge pulses applied to each subfield of the first group is less than a total number of the sustain discharge pulses applied to each subfield of a second group. ### Claim 11 (depends on 10) The plasma display device as claimed in claim 10, wherein the total number of the sustain discharge pulses applied to each subfield of the first group is less than fifteen. ### Claim 12 (depends on 8) The plasma display device as claimed in claim 8, wherein, in a reset period immediately following the sustain period, the driving circuit initializes discharge cells that have experienced a sustain discharge in the sustain period. ### Claim 13 (depends on 12) The plasma display device as claimed in claim 12, wherein the last sustain discharge pulse during the sustain period is applied to the first electrode. ### Claim 14 (depends on 9) The plasma display device as claimed in claim 9, wherein, in a reset period immediately following the sustain period, the driving circuit initializes discharge cells that have experienced a sustain discharge in the sustain period. ### Claim 15 (depends on 10) The plasma display device as claimed in claim 10, wherein, in a reset period immediately following the sustain period, the driving circuit initializes discharge cells that have experienced a sustain discharge in the sustain period. ### Claim 16 (depends on 8) The plasma device as claimed in claim 8, wherein the last sustain discharge pulse is applied to a sustain electrode. ### Claim 17 A plasma display device, comprising: a plurality of first electrodes; a plurality of second electrodes; a controller dividing one frame into a plurality of subfields, each subfield including a reset period, an address period, and a sustain period, and grouping the plurality of subfields into a plurality of groups according to the number of sustain discharge pulses; and a driving circuit applying a sustain discharge pulse, alternately having a positive first voltage and a negative second voltage, to the first electrodes and applying a third voltage to the second electrodes according to a control of the controller, wherein the controller sets a width of a last sustain discharge pulse applied to the first electrodes to be greater than a width of other sustain discharge pulses for selected subfields during a sustain period of a first group among the plurality of groups. ### Claim 18 (depends on 17) The plasma device as claimed in claim 17, wherein the first group has a total number of sustain discharge pulses applied during the sustain period less than a predetermined number. ### Claim 19 (depends on 17) The plasma device as claimed in claim 17, wherein the first electrode is a scan electrode and the second electrode is a sustain electrode.