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Electroluminescent display device having uniform display element column luminosity

  • US 5,973,456 A
  • Filed: 01/28/1997
  • Issued: 10/26/1999
  • Est. Priority Date: 01/30/1996
  • Status: Expired due to Term
First Claim
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1. An EL display device comprising:

  • an EL display panel having an electroluminescing layer interposed between a plurality of scan electrodes and a plurality of data electrodes, a plurality of EL elements being formed at locations where said scan electrodes and said data electrodes intersect;

    first voltage applying means for sequentially applying a voltage pulse to said plurality of scan electrodes; and

    second voltage applying means for selectively applying a display voltage to said plurality of data electrodes;

    wherein said plurality of EL elements are for emitting light by application of said voltage pulse and said display voltage; and

    said first voltage applying means is for applying said voltage pulse to said plurality of scan electrodes by charging said plurality of EL elements during a charging period and holding a charging voltage thereof for a holding period, for detecting a number of EL elements which are to emit light by application of said voltage pulse and said display voltage, and for varying said charging period in accordance with said number of detected EL elements;

    said first voltage applying means is further for holding said charging voltage by causing said plurality of scan electrodes to go to high impedance.

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