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Polarizer, polarization light source and image display unit using them

  • US 7,443,585 B2
  • Filed: 04/17/2003
  • Issued: 10/28/2008
  • Est. Priority Date: 04/23/2002
  • Status: Expired due to Fees
First Claim
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1. A polarization component comprising at least two reflective polarizer layers and a retardation layer disposed between the reflective polarizer layers, whereinthe two reflective polarizer layers are reflective circular polarizer layers that selectively transmit one of clockwise circularly polarized light or counterclockwise circularly polarized light while selectively reflecting the other, whereinthe two reflective circular polarizer layers have selective reflection wavelength bands for selective reflection of polarized light, the bands overlapping each other at least partially, andthe retardation layer satisfies conditions of Formulae (I) and (II) below:


  • R≦

    λ

    /
    10 



    (I)
    R≧

    λ

    /
    8 



    (II)wherein in Formulae (I) and (II), λ

    denotes a wavelength of light entering the retardation layer;

    R denotes an absolute value of retardation of an in-plane retardation in a X-axis direction and in a Y-axis direction with respect to incident light from a Z-axis direction (normal direction), where the X-axis direction is a direction showing a maximum refractive index within the plane of the retardation layer (in-plane slow axis direction), the Y-axis direction is a direction perpendicular to the X-axis direction within the plane of the retardation layer (in-plane fast axis direction), and the Z-axis direction is a thickness direction of the retardation layer and perpendicular to the X-axis direction and the Y-axis direction;

    R′

    denotes an absolute value of retardation between a X′

    -axis direction and a Y′

    -axis direction with respect to incident light from a direction inclined by at least 30°

    with respect to the Z-axis direction, where the X′

    -axis direction is an axial direction within a plane of the retardation layer perpendicular to the incidence direction of the incident light inclined by at least 30°

    with respect to the Z-axis direction, and the Y′

    -axis direction is a direction perpendicular to the incidence direction and to the X′

    -axis direction.

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