Plasma display apparatus

• US 5,231,382 A
• Filed: 02/27/1991
• Issued: 07/27/1993
• Est. Priority Date: 02/27/1990
• Status: Expired due to Term

• Current Assignee: Pioneer Corporation
• Original Assignee: NEC Corporation
• Inventors: Tanaka, Akio
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): MENGISTU, AMARE
• Application Number:
  US07/662,006
• Time in Patent Office: 881 Days
• Field of Search: 340/771, 340/781, 340/767, 340/776, 340/784, 340/767, 340/805, 315/169.4
• US Class Current: 345/60
• CPC Class Codes: G09G 3/2944 by varying the frequency of sustain pulses or the number of sustain pulses proportionally in each subfield of the whole frame
• CPC Class Codes: G09G 3/297 using opposed discharge type panels

Abstract

The invention provides voltage potential differences for selectively discharging cells in a plasma display device, with greater brightness and reduced power consumption. The driving pulses applied to either selected cells or non-selected cells during one scanning cycle includes a high frequency hold mode period after a low frequency address mode period. During the hold mode period, a duty factor of its pulse train is selected to be smaller than that of the address mode period. Particularly, the pulse width of the pulse train in the hold mode period is shorter than an interval of pulses thereof. In other words, the duty factor of the hold mode period is selected to be less than 1/2 to decrease the voltage causing an erroneous discharge. In another embodiment, to improve brightness, the duration of hold mode is, extended to cover one more scanning cycle.

Claims

1. A plasma display apparatus comprising a first electrode group and a second electrode group disposed in an opposed relation relative to each other, the space intermediary of the opposed electrode groups being filled with a discharge gas to form cells therebetween, the plasma display comprising:

first means for applying a first pulse train of first voltage to said first electrode group for a first period at a predetermined interval in a time division mode;

second means for applying a second pulse train of said first voltage to said first electrode group for a second period following successively said first pulse train, a frequency of said second pulse train being higher than that of said first pulse train, and a duty factor of said second pulse train being of a value smaller than that of said first pulse train, where the duty factor is a ratio of a pulse width to a pulse period;

third means for applying a third pulse train of second voltage to at least one selected electrode in said second electrode group for said first period, said third pulse train being applied in synchronism and in combination with said first pulse train so as to produce a first pulsing potential difference between the electrodes associated with a selected cell, a phase of said third pulse train being opposite to a phase of said first pulse train such that said first pulsing potential difference is larger than a firing voltage of said cell to provide an address mode operation;

fourth means for applying to non-selected electrodes in said second electrode group and during said first period a fourth pulse train of third voltage pulses in synchronism with said first pulse train so as to produce a second pulsing potential difference between the electrodes associated with non-selected cells in combination with said first pulse train, a phase of said fourth pulse train being identical to the phase of said first pulse train such that said second pulsing potential difference is less than the firing voltage of said cell;

fifth means for applying a first direct-current voltage component in combination with said second pulse train to said at least one selected electrode in said second electrode group during said second period so as to produce a third pulsing potential difference between the electrodes associated with said selected cell, said third pulsing potential difference being smaller than the firing voltage of said cell, but also being large enough to continue the discharge of said selected cell due to a previously discharging state of said selected cell to provide a hold mode operation; and

sixth means for applying a second direct-current voltage component in combination with said second pulse train to said non-selected electrodes in said second electrode group for said second period so as to produce a fourth pulsing potential difference between the electrodes associated with a non-selected cell, said fourth pulsing potential difference being less than the firing voltage of said cell,

wherein the duty factor of said second pulse train is selected to be less than 1/2 during said hold mode operation.

2. The apparatus of claim 1, wherein a pulse width of said second pulse train is selected to be 70 nsec to 160 nsec.

3. The apparatus of claim 1, wherein said second period is longer than said first period.

4. A plasma display apparatus comprising a first electrode group and a second electrode group disposed in an opposed relation relative to each other, the space intermediary of the opposed electrode groups being filled with a discharge gas to form cells therebetween, the plasma display comprising:

first means for applying a first pulse train of first voltage to said first electrode group for a first period at a predetermined interval in time division mode;

second means for applying a second pulse train of said first voltage to said first electrode group for a second period following successively said first pulse train, a frequency of said second pulse train being higher than said that of said first pulse train, and a duty factor of said second pulse train being of a value smaller than that of said first pulse train, where the duty factor is a ratio of a pulse width to a pulse period;

third means for applying a third pulse train of second voltage to at least one selected electrode in said second electrode group for said first period, said third pulse train being applied in synchronism and in combination with said first pulse train so as to produce a first pulsing potential difference between the electrodes associated with a selected cell, a phase of said third pulse train being opposite to a phase of said third pulse train such that said first pulsing potential difference is larger than a firing voltage of said cell to provide an address mode operation;

fourth means for applying to non-selected electrodes in said second electrode group and during said first period a fourth pulse train of third voltage pulses in synchronism with said first pulse train so as to produce a second pulsing potential difference between the electrodes associated with non-selected cells in combination with said first pulse train, a phase of said fourth pulse train being identical to the phase of said first pulse train such that said second pulsing potential difference is less than the firing voltage of said cell;

fifth means for applying a first direct-current voltage component in combination with said second pulse train to said at least one selected electrode in said second electrode group during said second period so as to produce a third pulsing potential difference between the electrodes associated with said selected cell, said third pulsing potential difference being smaller than the firing voltage of said cell, but also being large enough to continue the discharge of said selected cell due to a previously discharging state of said selected cell to provide a hold mode operation; and

sixth means for applying a second direct-current voltage component in combination with said second pulse train to said non-selected electrodes in said second electrode group for said second period so as to produce a fourth pulsing potential difference between the electrodes associated with a non-selected cell, said fourth pulsing potential difference being less than the firing voltage of said cell, wherein

the duty factor of said second pulse train is selected to be less than 1/2 during said hold mode operation;

said second pulse train is selected to be 70 nsec to 160 nsec, and

said second period is longer than said first period.