Patent US5513036A successfully refreshed from Google Patents.
US5513036A
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US
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Projection screen
Assignee: Dai Nippon Printing Co Ltd
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Filing: 1994-08-30
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Granted: 1996-04-30
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Expires: 2014-08-30
Abstract
Abstract In a projection screen for a rear projection type television set, three lens sheets are arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet, and a circular Fresnel lens sheet when seen from a viewer's side toward a projector tube. As compared with the arrangement in which the linear and circular Fresnel lens sheets are exchanged with each other, it is possible to obtain a higher brightness and a more uniform brightness, and color uniformity in the picture plane. Further, when the light incident surface of the linear Fresnel lens sheet is matted, it is possible to eliminate white bands (seen from the viewer's side) effectively.
Inventors
- 👤 Hitomu Watanabe
- 👤 Makoto Honda
- 👤 Hiroshi Kojima
- 👤 Satoshi Nakamae
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:10
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/54; G03B21/56; G03B21/60; G03B21/62; G03B21/625; H; H04; H04N; H04N5/00; H04N5/74; H04N5/7408
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
137 words
A projection screen for a rear projection type television set, having a plurality of lens sheets arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet, and a circular Fresnel lens sheet when seen from a viewer's side, wherein a lens angle ψ of said linear Fresnel lens sheet is obtained in accordance with the following expressions: ##EQU5## where: θ.sub. : Incident light angle θ: Outgoing light angle ψ: Linear Fresnel lens angle n L : Linear Fresnel lens refractive index φ: Circular Fresnel lens angle v: Vertical coordinate value of linear Fresnel lens n c : Circular Fresnel lens refractive index f 1 : Projection distance f 2 : Vertical light converging distance PJ: Vertical coordinate value of light source (A) (CRT) h f : Vertical coordinate value of image formation point.
Claim 2
Dependent Claim
137 words
A projection screen for a rear projection type television set, having a plurality of lens sheets arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet, and a circular Fresnel lens sheet when seen from a viewer's side, wherein a lens angle ψ of said linear Fresnel lens sheet is obtained in accordance with the following expressions: ##EQU5## where: θ.sub. : Incident light angle θ: Outgoing light angle ψ: Linear Fresnel lens angle n L : Linear Fresnel lens refractive index φ: Circular Fresnel lens angle v: Vertical coordinate value of linear Fresnel lens n c : Circular Fresnel lens refractive index f 1 : Projection distance f 2 : Vertical light converging distance PJ: Vertical coordinate value of light source (A) (CRT) h f : Vertical coordinate value of image formation point.
Claim 3
Dependent Claim
29 words
The projection screen of claim 1, wherein said linear Fresnel lens sheet and said circular Fresnel lens sheet are arranged by directing lens formation surfaces thereof toward the viewer.
Claim 4
Dependent Claim
59 words
A projection screen for a rear projection type television set, having a plurality of lens sheets in the order of a lenticular lens sheet, a linear Fresnel lens sheet, and a circular Fresnel lens sheet when seen from a viewer's side, said circular Fresnel lens sheet having a refractive index larger than that of said linear Fresnel lens sheet.
Claim 5
Dependent Claim
59 words
A projection screen for a rear projection type television set, having a plurality of lens sheets in the order of a lenticular lens sheet, a linear Fresnel lens sheet, and a circular Fresnel lens sheet when seen from a viewer's side, said circular Fresnel lens sheet having a refractive index larger than that of said linear Fresnel lens sheet.
Claim 6
Dependent Claim
29 words
The projection screen of claim 3, wherein said linear Fresnel lens sheet and said circular Fresnel lens sheet are arranged by directing lens formation surfaces thereof toward the viewer.
Claim 7
Dependent Claim
82 words
A projection screen for a rear projection type television set, having a plurality of lens sheets arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet in the form of a film, and a circular Fresnel lens sheet when seen from a viewer's side, wherein at least said lenticular lens sheet and said circular Fresnel lens sheet are curved, and said linear Fresnel lens sheet is sandwiched between said circular Fresnel lens sheet and said lenticular lens sheet.
Claim 8
Dependent Claim
82 words
A projection screen for a rear projection type television set, having a plurality of lens sheets arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet in the form of a film, and a circular Fresnel lens sheet when seen from a viewer's side, wherein at least said lenticular lens sheet and said circular Fresnel lens sheet are curved, and said linear Fresnel lens sheet is sandwiched between said circular Fresnel lens sheet and said lenticular lens sheet.
Claim 9
Dependent Claim
86 words
A projection screen for a rear projection type television set, having a plurality of lens sheets arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet in the form of a film, and a circular Fresnel lens sheet when seen from a viewer's side, wherein said linear Fresnel lens sheet is composed of a base film and a lens group formed on said base film, said lens group comprising at least one of ultraviolet-ray hardening type resins and electron-beam hardening type resins.
Claim 10
Dependent Claim
86 words
A projection screen for a rear projection type television set, having a plurality of lens sheets arranged in the order of a lenticular lens sheet, a linear Fresnel lens sheet in the form of a film, and a circular Fresnel lens sheet when seen from a viewer's side, wherein said linear Fresnel lens sheet is composed of a base film and a lens group formed on said base film, said lens group comprising at least one of ultraviolet-ray hardening type resins and electron-beam hardening type resins.
Claim 11
Dependent Claim
34 words
The projection screen of claim 6, wherein said linear Fresnel lens sheet film is formed with a matted surface on a light incoming surface of said base film, to diffuse internally reflected stray light.
Claim 12
Dependent Claim
36 words
The projection screen of claim 6, wherein said linear Fresnel lens sheet is formed with a matted surface on a boundary surface between said base film and said lens group, to diffuse internally reflected stray light.
Claim 13
Dependent Claim
55 words
The projection screen of claim 6, wherein said linear Fresnel lens sheet further comprises a microlenticular lens sheet formed on a light incoming surface of said base film in such a way that said microlenticular lens is arranged in parallel to the lenses of the linear Fresnel lens sheet, to diffuse internally reflected stray light.
References Cited (Backward Citations)
JPS5915925A
Cited
US5408282A
Cited
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