Horizontal electric field LCD with increased capacitance between pixel and common electrodes

  • US 6,404,474 B1
  • Filed: 07/19/1999
  • Issued: 06/11/2002
  • Est. Priority Date: 07/24/1998
  • Status: Expired due to Term
First Claim
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1. An active matrix type liquid crystal display device comprising two opposing transparent insulating substrates and liquid crystal interposed therebetween, wherein said liquid crystal is controlled by generating an electric field substantially parallel to the liquid crystal layer with a voltage applied between pixel electrodes and common electrodes both disposed on the first of said substrates, said display device further comprising:

  • on said first substrate;

    a plurality of scanning lines and a plurality of signal lines orthogonal to one another;

    a thin film transistor provided near each intersection of a scanning line and a signal line;

    common electrodes extending substantially parallel to said scanning lines and having a plurality of comb-tooth projections extending toward said scanning lines;

    pixel electrodes formed substantially parallel to the comb-tooth projections in gaps between the adjacent comb-tooth projections of said common electrodes when said substrate is viewed from the normal direction, at least a portion of each pixel electrode being opposite to a common electrode interposed by an interlayer insulating film;

    an interlayer insulating film disposed between said common electrodes and said pixel electrodes; and

    a first alignment film formed above said pixel electrodes interposed by a protective insulating film;

    on said second substrate;

    a black matrix provided with openings in areas opposite to each of said pixel electrodes; and

    a second alignment film; and

    said active matrix type liquid crystal display device further comprising;

    accumulated capacitance increasing means for obtaining an accumulated capacitance between said pixel electrode and said common electrodes larger than that generated when said interlayer insulating film is of even thickness and flat structure.

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