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Process for producing shaded colored images using dithering techniques

  • US 5,757,347 A
  • Filed: 05/17/1993
  • Issued: 05/26/1998
  • Est. Priority Date: 12/24/1991
  • Status: Expired due to Term
First Claim
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1. In a color display apparatus having an array of picture elements each including plural picture sub-elements each of a different color and each having more than two display states selected between using at least two input terminals, each of which has two possible inputs, an ON input and an OFF input, a method of simulating display colors in addition to a number of display colors otherwise available using said color display apparatus, comprising the steps of:

  • modulating an ON/OFF duty cycle of a least significant one of said at least two input terminals of each picture sub-element of the array of picture elements during a multi-frame display sequence according to attribute information of respective picture element data to be displayed; and

    coordinating the timing of ON/OFF and OFF/ON input transitions on said least significant input terminal of each picture sub-element within each of a plurality of predetermined display neighborhoods throughout the array of picture elements such that said input transitions cause state transitions of said picture sub-elements to occur substantially uniformly in space and time, within each display neighborhood, during the multi-frame display sequencewherein said color display apparatus is a thin-film transistor LCD display,wherein each picture element has at least eight display states selected between using at least three input terminals,wherein said multi-frame sequence is 64 frames long and is logically divided into four sub-sequences each 16 frames long,wherein 260 shades of each picture sub-element are realized by causing the ON/OFF duty cycle of said least significant input terminal of each picture sub-element to have a value within the set {0, 1/64, 2/64, . . . , 64/64}, andwherein the ON/OFF duty cycle of said least significant input terminal of each picture sub-element during each of said four 16-frame sub-sequences of said 64 frame sequence is caused to have a value within the set {0, 1/16, 2/16, . . . , 16/16}.

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