US 7,460,300 B2
Projection-type picture display apparatus and screen used thereby
Koji Hirata, Yokohama (Japan); and Shigeru Inaoka, Yokohama (Japan)
Assigned to Hitachi, Ltd., Tokyo (Japan)
Filed on May 21, 2007, as Appl. No. 11/802,125.
Application 11/802125 is a continuation of application No. 11/325521, filed on Jan. 05, 2006, granted, now 7,221,507.
Application 11/325521 is a continuation of application No. 10/827338, filed on Apr. 20, 2004, granted, now 7,023,616.
Application 10/827338 is a continuation of application No. 09/412578, filed on Oct. 05, 1999, granted, now 6,728,031.
Claims priority of application No. 10-282261 (JP), filed on Oct. 05, 1998.
Prior Publication US 2007/0223089 A1, Sep. 27, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. G03B 21/60 (2006.01); G03B 21/56 (2006.01)
U.S. Cl. 359—457  [359/460] 3 Claims
OG exemplary drawing
 
1. A screen for use in a projection-type image display apparatus having an image displaying element which includes a plurality of pixels for modulating a light from a light source so as to form an image formed by said image displaying element to be projected on said screen as an enlarged picture, said screen comprising:
a Fresnel lens sheet;
a first sheet disposed on a light emission side of said Fresnel lens sheet; and
a second sheet disposed on a light emission side of said first sheet;
wherein said first sheet includes a plurality of lenticular lenses formed on a light incident side thereof, said lentiular lenses extending in a longitudinal direction and being arranged in a horizontal direction, light passing window portions formed at positions opposing to said lenticular lenses with light absorbing portions provided between said light passing window portions;
wherein the following equations are satisfied:
1.558≤Lp/Fp≤1.649;
Lp<Iph; and
Ipv/Fp≧2;
where Fp is a pitch between Fresnel lenses formed on said Fresnel lens sheet, Lp is a pitch of the light absorbing portions provided on said first sheet, Iph is a pixel pitch of said image display element which is projected so as to form an enlarged picture on said screen in a horizontal direction, and Ipv is a pixel pitch thereof in a vertical direction.