Liquid crystal display device having phase different plates

  • US 6,226,061 B1
  • Filed: 03/24/1998
  • Issued: 05/01/2001
  • Est. Priority Date: 03/25/1997
  • Status: Expired due to Term
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First Claim
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1. A liquid crystal display device comprising:

  • a liquid crystal display element including at least a counter substrate, a pixel substrate, and a liquid crystal layer, wherein;

    said counter substrate has a common electrode, said pixel substrate or said counter substrate having a plurality of color filters;

    said pixel substrate has scanning lines, signal lines, switching elements each being provided in the vicinity of each point of intersection of said scanning lines and said signal lines, and pixel electrodes each being connected with each switching element, each switching element having a gate electrode connected with said scanning line, a source electrode connected with said signal line, and a drain electrode connected with said pixel electrode, each scanning line, signal line and switching element being covered with an interlayer insulating film being composed of an organic film whose optical transmittance is not less than about 95 percent with respect to light which is emitted from a light source and has a peak wavelength in the vicinity of a wavelength band of colors of said color filters, each pixel electrode being provided on each interlayer insulating film; and

    said liquid crystal layer is provided between said counter substrate and said pixel substrate, and is made of liquid crystal whose refractive index anisotropy Δ

    n(450) with respect to light with a wavelength of 450 nm and whose refractive index anisotropy Δ

    n(650) with respect to light with a wavelength of 650 nm satisfy a condition that a difference Δ



    n(650) between the refractive index anisotropies is in a range of 0 to 0.01, said liquid crystal display device further comprising;

    a pair of polarizers, each being provided on each side of said liquid crystal display element; and

    at least one phase difference plate provided between said liquid crystal display element and said polarizers, three main refractive indexes na, nb, and nc of an index ellipsoid of said phase difference plate satisfying na=nc>

    nb at least in a representative layer of the same, either the main refractive index na or nc being parallel with a surface of said phase difference plate, the index ellipsoid being inclined, with a direction of the main refractive index nb being turned clockwise or anti-clockwise around the main refractive index na or nc direction parallel with the surface of said phase difference plate as an axis, so as to shift from a state where the index ellipsoid is parallel with a normal direction of the surface of said phase difference plate to an inclined state.

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