SCREEN FOR PRODUCING AN ENHANCED IMPRESSION OF DEPTH

• US 3,820,873 A
• Filed: 04/26/1973
• Issued: 06/28/1974
• Est. Priority Date: 04/26/1973
• Status: Expired due to Term

• Current Assignee: Henkes J, Redington R
• Original Assignee: Henkes J, Redington R
• Inventors: REDINGTON R, HENKES J
• Application Number:
  US05/354,895
• Time in Patent Office: 428 Days
• US Class Current: 359/451
• CPC Class Codes: G02B 30/40 giving the observer of a single two-dimensional [2D] image a perception of depth
• CPC Class Codes: G03B 21/56 Projection screens

Abstract

An enhanced impression of depth is obtained from a projection screen having a concave surface formed by forward curving edges at the sides and bottom. The central portion of the screen is flat, or has a large radius of curvature, and the edges have a small radius of curvature. A section of the screen approximates the shape of an elongated ellipse, i.e. with major axes in the ratio of 8:1 or greater.

Claims

1. An improved surface for presenting two dimensional images with a visual impression of depth comprising:

a image surface having a central portion and side and bottom edge portions;

said central portion comprising from 50-90 percent of the total viewing area;

said edge portions curving toward the viewer to produce a concave surface, and having a radius of curvature of from approximately 0.1 to 1.0 times the larger of the width or height dimensions of said surface; and

said central portion having a radius of curvature in excess of ten times the smaller of said width or height dimensions.

2. An improved surface as set forth in claim 1 wherein the radius of curvature of said central portion is substantially infinite.

3. An improved surface as set forth in claim 1 wherein the radii of curvature of said central and edge portions vary along each of said dimensions of said surface to provide a smooth curve.

4. An improved surface as set forth in claim 3 wherein said curve forms an elongated ellipse.

5. An improved surface as set forth in claim 3 wherein said curve forms a hypocycloid.

6. An improved surface as set forth in claim 5 wherein said hypocycloid is one of a family defined by two circles having radii in the ratio of 4:

1.

7. An improved surface as set forth in claim 1 wherein said surface forms a rear projection surface.

8. An improved surface as set forth in claim 1 wherein said surface forms a front projection surface.

9. An improved surface as set forth in claim 8 wherein said surface is discontinuous in said edge portions.

10. An improved surface as set forth in claim 9 wherein said edge portions are faceted.

11. An improved front projection system for viewing two dimensional images comprising:

a projection screen having a central portion, comprising 50-90 percent of the total viewing area, and edge portions curving toward the viewer to produce a concave surface;

said edge portions having a radius of curvature of from approximately 0.1 to 1.0 times the larger of the width or height dimensions of said screen, and said central portion having a radius of curvature greater than ten times the smaller of said dimensions;

a projector positioned in front of said screen for causing a projection beam to be incident upon said screen; and

beam splitting means, intercepting the edges of said projection beam to form edge beams, for re-orienting said edge beams approximately perpendicular to said edge portions of said projection screen.

12. An improved projection system as set forth in claim 11 wherein said beam splitting comprises:

mirror means, intercepting the edge of said projection beam, for re-orienting the direction of said edge beams; and

beam path correction means for focusing said edge beams on the edge portions of said projection screen.