Wide angle rear projection lenticular lens system

• US 5,428,476 A
• Filed: 04/07/1994
• Issued: 06/27/1995
• Est. Priority Date: 04/07/1994
• Status: Expired due to Term

• Current Assignee: Stewart Filmscreen Corporation
• Original Assignee: Stewart Filmscreen Corporation
• Inventors: Scott, Steve M., Jensen, Holger
• Primary Examiner(s): WINTERCORN, RICHARD
• Application Number:
  US08/224,336
• Time in Patent Office: 446 Days
• Field of Search: 359/453, 359/454, 359/455, 359/456, 359/460, 359/457
• US Class Current: 359/457
• CPC Class Codes: G03B 21/625 Lenticular translucent screens

Abstract

A wide angle lenticular lens system for a single piece rear projection screen including a plurality of substantially identical parallel and vertical lenticular lenses. Each of the plurality of lenticular lenses is substantially a single element lens and the shape of each of the plurality of lenticular lenses is substantially defined by a hyperbolic function.

Claims

1. A wide angle lenticular lens system for single piece rear projection screens comprising a plurality of identical vertical lenticular lens and wherein:

each of said plurality of said lenticular lens is parallel;

each of said plurality of said lenticular lens is composed of a single element lens; and

a shape of each of said plurality of lenticular lens is defined by a hyperbolic function;

space="preserve" listing-type="equation">(X.sup.n /A.sup.n)-(Y.sup.n /B.sup.n)=1

wherein a ratio of B to A is chosen to optimize an asymptote angle of a side of each of said plurality of lenticular lens with respect to incoming light into the lenticular lens so that most of the light impinging on a side of each of said lenticular lens is internally reflected out through an end portion of said lenticular lens and n is chosen to optimize a curvature of said end portion of each of said lenticular lens based upon an index or refraction of a material from which the lenticular lens is made so that light internally reflected from said sides of said lenticular lens impinges on said curvature of said end portion at an angle less than a critical angle;

whereby substantially all the light entering each of said plurality of lenticular lens exits through said end portion and a wide horizontal viewing half angle is provided.

2. A lenticular lens system according to claim 1 wherein the lenticular lens is made from an acrylate material.

3. A lenticular lens system according to claim 2 wherein said acrylate material is polymerized methyl-methacrylate having an index of refraction of 1.491.

4. A lenticular lens system according to claim 3 wherein the ratio of B to A is approximately equal to 2.5 and the critical angle is 42°

.

5. A lenticular lens system according to claim 1 wherein each of said plurality of lenticular lens is a single element lens.

6. A lenticular lens system according to claims 1 or 5 wherein a surface of said lenticular lens is chemically etched.

7. A lenticular lens system according to claim 2 wherein a colorant is added to the material from which said lenticular lens system is made.

8. A lenticular lens according to claim 2 or 7 wherein diffusing particles are added to the material from which said lenticular lens is made.

9. A lenticular lens according to claim 1 wherein said lenticular lens is made from a transparent plastic suitable for optical use.

10. A lenticular lens according to claim 1 further comprising a fresnel lens.