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Reflection type color liquid crystal display apparatus

  • US 5,953,090 A
  • Filed: 02/06/1997
  • Issued: 09/14/1999
  • Est. Priority Date: 06/07/1995
  • Status: Expired due to Term
First Claim
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1. A reflection type liquid crystal display apparatus comprising:

  • a polarizing plate,a birefringent plate having a twist angle,a liquid crystal layer of a nematic liquid crystal having positive dielectric anisotropy and including a chiral material, which is interposed between two substrates disposed to each other, each provided with an electrode, anda reflection layer arranged in successive order;

    whereinsaid liquid crystal layer hasa twist angle θ

    1 from the first orientation direction at its first plane of said liquid crystal layer to the second orientation direction at its second plane of said liquid crystal layer;

    said birefringent plate has a twist angle θ

    2 from a first slow axis of optical anisotropic axes in a plane at the side next to the polarizing plate to a second slow axis of optical anisotropic axes in opposite plane in a direction from the first slow axis to the second slow axis, andthe product of Δ

    n1 ·

    d1 of the refractive index anisotropy Δ

    n1 of the liquid crystal in the liquid crystal layer and the thickness d1 of the liquid crystal layer is 0.30 to 2.00 μ

    m;

    the product of Δ

    n2 ·

    d2 of the refractive index anisotropy Δ

    n2 of the birefringent plate and the thickness d2 of the birefringent plate is 0.30 to 2.00 μ

    m;

    an angle θ

    3 is formed from said first orientation direction of the liquid crystal layer to the second slow axis of said birefringent plate;

    an angle θ

    4 is formed from said first slow axis of said birefringent plate to an absorbing axis of said polarizing plate;

    the angles θ

    1, θ

    2, θ

    3 and θ

    4 in a clockwise (+) or in counterclockwise (-) direction have the following first conditions;



    1 is -160°

    to -300°



    2 is +160°

    to +300°



    3 is (+90°

    + -10°

    to +40°

    !) andθ

    4 is (+45°

    + -30°

    to +25°

    ! or +135°

    + -30°

    to +25°

    !)};

    or the following second conditions;



    1 is +160°

    to +300°



    2 is -160°

    to -300°



    3 is (-90°

    + +10°

    to -40°

    !) andθ

    4 is (-45°

    + +30°

    to -25°

    ! or -135°

    + +30°

    to -25°

    !)};

    and voltage values of at least 3 values are selected to be applied to said liquid crystal layer.

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