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Gray scales method and circuitry for flat panel graphics display

  • US 5,196,839 A
  • Filed: 10/15/1990
  • Issued: 03/23/1993
  • Est. Priority Date: 09/16/1988
  • Status: Expired due to Term
First Claim
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1. A controller for controlling a monochrome video display, the monochrome video display comprised of a plurality of pixel elements, the pixel elements having a non-linear response of a first predetermined time period to the application of a predetermined display voltage, the controller providing zero to N gray scale levels of the pixel elements, the controller comprising:

  • table means for storing zero to N time periods, the N time periods corresponding to the zero to N gray scale levels, wherein the N time periods corresponding to gray scale levels two to N are dependent upon an incremental time period, the incremental time period being determined by the steps of;

    determining a minimum baseline time for applying the predetermined display voltage to a pixel element, the minimum baseline time corresponding to the time period necessary to apply the display voltage to charge pixel element to gray scale level one, the minimum baseline time being at least equal to the first predetermined time period during which the pixel has a non-linear response to the predetermined voltage;

    determining a maximum time that the display voltage can be applied to a pixel element, the maximum time corresponding to the time period necessary to apply the display voltage to charge the pixel element to the gray scale level N;

    subtracting the minimum baseline time from the maximum time;

    dividing the result of the subtracting step by N, the maximum gray level, the result being the incremental time; and

    means for applying the display voltage to the pixel elements for a time equal to the zero to N time periods, wherein time period one is equal to the minimum baseline time and time periods two through N correspond to the minimum baseline time added to the incremental time period multiplied by two through N, respectively.

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