Lenticular lens sheet for use in rear projection television
First Claim
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.
1 Assignment
0 Petitions
Accused Products
Abstract
A lenticular lens sheet for a rear projection television, which exhibits smooth color change and has a wide viewing angle even in a television set having a large convergence angle. A group of vertical straight-line shaped entrance-side lens surfaces are provided on an entrance side I of the lenticular lens sheet. Each entrance-side lens surface has a cross-section defined approximately by a part of an ellipse, and satisfies the condition of 2.5≦bp/a2 ≦3.0, where b is the major axis of the ellipse; a is the minor axis of the ellipse; and p is the width of each entrance-side lens surface. A group of vertical straight-line shaped exit-side lens surfaces are provided on an exit side O of the lenticular lens sheet. Each exit-side lens surface has a cross-section defined approximately by a part of an ellipse, and satisfies the condition of 0.55≦b/(a2 φ)≦0.75, where φ is a convergence angle formed by two adjacent projection tubes. A light-absorbing layer BS is provided on each light-blocking portion. The thickness L of the lenticular lens sheet from the bottom of the entrance-side lens surface I to the vertex of the exit-side lens surface O is set so that light entering the lens through the bottom of the entrance-side lens surface I intersects the center axis outside the exit-side lens surface O.
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Citations
4 Claims
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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; anda 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; andn;
a refractive index of said lenticular lens sheet. - View Dependent Claims (2, 3, 4)
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Specification