Optical: systems and elements – Projection screen – Unitary sheet comprising plural refracting areas
Patent
1997-03-21
1999-03-30
Metjahic, Safet
Optical: systems and elements
Projection screen
Unitary sheet comprising plural refracting areas
G03B 2160
Patent
active
058896139
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.ltoreq.bp/a.sup.2 .ltoreq.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.ltoreq.b/(a.sup.2 .phi.).ltoreq.0.75, where .phi. 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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Dai Nippon Printing Co. Ltd.
Mahoney Christopher E.
Metjahic Safet
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