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Plasma Panel Write Normalizing Waveform

IP.com Disclosure Number: IPCOM000060744D
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Kleen, BG: AUTHOR

Abstract

This article discloses a write normalizing waveform for a plasma panel having a relatively slow ramp to automatically compensate for cell, panel and sustain/write voltage variations. The write operation of a plasma display panel is normally biased in a way to assure the writing of the most difficult to write cell. As a result, the majority of written cells will be excessively charged. When applying a sustaining waveform, Vs, as shown in Fig. 1, these cells may self-erase on the first fast transition to the mid-point level. The slew rate for this transition is typically 100-200 volts per microsecond. In the absence of a mid-point hesitation, the succeeding avalanche discharge will be excessive and demanding of the circuit design. A solution to this problem is to partially discharge the excess with the waveform shown in Fig. 2.

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Plasma Panel Write Normalizing Waveform

This article discloses a write normalizing waveform for a plasma panel having a relatively slow ramp to automatically compensate for cell, panel and sustain/write voltage variations. The write operation of a plasma display panel is normally biased in a way to assure the writing of the most difficult to write cell. As a result, the majority of written cells will be excessively charged. When applying a sustaining waveform, Vs, as shown in Fig. 1, these cells may self-erase on the first fast transition to the mid-point level. The slew rate for this transition is typically 100-200 volts per microsecond. In the absence of a mid-point hesitation, the succeeding avalanche discharge will be excessive and demanding of the circuit design. A solution to this problem is to partially discharge the excess with the waveform shown in Fig. 2. The relatively slow ramp of voltage (5-6 volts per microsecond) will automatically accommodate the variation in excess charge of the various cells by discharging each to a voltage level approximately equal to the ramp voltage at the time of initiation. Even those cells which discharge at the end of the ramp will not erase due to a finite recombination time extending into the next sustain transition. The circuitry needed to generate the slow ramp is identically that which generates the corresponding transition in the sustain waveform with simply a switch in the slew rate control component. Multiple use ...