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Capacitive Shift Write for AC Plasma Panel

IP.com Disclosure Number: IPCOM000086081D
Original Publication Date: 1976-Jul-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Related People

Beidl, JR: AUTHOR [+2]

Abstract

In order to fire a plasma panel, a write signal higher than the sustaining voltage is required. Typically, the write signal is generated by a write pulse from an additional power supply or pulse transformer which is superimposed on the sustain signal. A method of generating a write pulse without an additional power supply or pulse transformer operates as follows.

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Capacitive Shift Write for AC Plasma Panel

In order to fire a plasma panel, a write signal higher than the sustaining voltage is required. Typically, the write signal is generated by a write pulse from an additional power supply or pulse transformer which is superimposed on the sustain signal. A method of generating a write pulse without an additional power supply or pulse transformer operates as follows.

Referring to the drawings, Fig. 1 illustrates in block form a conventional sustain generator used to drive one axis of a gas panel.

When switch 11 is closed and switch 13 is open, the panel line 15 is held to +Vs supplied from line 17. When switch 11 is open and switch 13 is closed, the panel line is held to the ground level from line
19. Thus by the action of switches 11 and 13 a sustain waveform is generated and applied via line 15 to its associated panel line. An AC plasma panel with both axes driven requires two such sustain generators.

Fig. 2 illustrates the manner in which the conventional sustain generator illustrated in Fig. 1 is modified to produce a write pulse. The additional components required are two switches 21, 23, a diode 25, a capacitor 27, and a current source 29. The write pulse is produced as follows. Switch 21 is maintained on during the on time of switch 11 to ensure that the write capacitor 27 is always at the same potential before it is charged.

When switch 11 is turned off and switch 13 turned on, switch 21 remains on to charge the write capacitor 27 to some positive potential through the current source 29. Current source 29 is used to provide a linear rate of charge to capacitor 27. The linear ramp generated by current source 29 allows the magnitude of the charge to be directly proportioned...