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Lenticular lens sheet for use in rear projection television

  • US 5,889,613 A
  • Filed: 03/21/1997
  • Issued: 03/30/1999
  • Est. Priority Date: 03/25/1996
  • Status: Expired due to Fees
First Claim
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1. A lenticular lens sheet used for a rear projection screen of a rear projection television, said lenticular lens sheet comprising:

  • a group of vertical straight-line shaped entrance-side lens surfaces provided on an entrance side of said lenticular lens sheet, said entrance-side lens surfaces each having a cross-section defined by a part of an ellipse, and said entrance-side lens surfaces satisfying the following condition;

    2.5≦

    bp/a2

    3.0where b is a major axis of said ellipse;

    a is a minor axis of said ellipse; and

    p is a width of each of said entrance-side lens surfaces;

    a group of vertical straight-line shaped exit-side lens surfaces provided on an exit side of said lenticular lens sheet, said exit-side lens surfaces each having a light-blocking portion and a cross-section defined by a part of an ellipse, said exit-side lens surfaces satisfying the following condition;

    0.55≦

    b/(a2 φ

    )≦

    0.75where b is a major axis of said ellipse;

    a is a minor axis of said ellipse; and

    φ

    is an angle formed by two adjacent projection tubes with respect to a center of a screen sheet; and

    a light-absorbing layer provided on each of said lightblocking portions of said exit-side lens surfaces;

    wherein a thickness L of said lenticular lens sheet from a bottom of each entrance-side lens surface to a vertex of each exit-side lens surface satisfies the following condition;

    L≦

    p/ 2 tan {θ

    1 -arcsin(sin θ

    1)/n}!where p;

    a lenticular lens pitch of said lenticular lens sheet;

    θ

    1 ;

    an angle of a normal to the entrance-side lens surface at the bottom of the entrance-side lens surface; and

    n;

    a refractive index of said lenticular lens sheet.

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