Rear-projection viewing screen

• US 4,076,384 A
• Filed: 04/27/1976
• Issued: 02/28/1978
• Est. Priority Date: 05/02/1975
• Status: Expired due to Term

• Current Assignee: Agfa-Gevaert AG (Agfa-Gevaert N.V.)
• Original Assignee: Agfa-Gevaert AG (Agfa-Gevaert N.V.)
• Inventors: Hofmann, Wilfried, Rauffer, Walter, Greis, Ulrich, Deml, Reinhold
• Primary Examiner(s): Wintercorn, Richard A.
• Application Number:
  US05/680,877
• Time in Patent Office: 672 Days
• Field of Search: 350/122, 350/33, 350/45, 350/130, 350/127, 353/94, 353/7, 353/34, 353/38, 353/82
• US Class Current: 359/448
• CPC Class Codes: G03B 21/625 Lenticular translucent screens

Abstract

The rear-projection viewing screen receives light incident upon its back side from the objective of a rear-projection projector and forms a corresponding image visible to a human eye viewing the front side of the viewing screen. The viewing screen is comprised of a lens-aperture matrix and an optical system cooperating with the lens-aperture matrix. The optical system serves the function of a lens matrix comprised of lens-matrix elements which focus the light from the objective of the rear-projection projector through the apertures of the lens-aperture matrix. The optical system furthermore serves the function of a field lens operative for gathering the light emanating from the objective of the projector and deflecting such light in direction toward the optical axis of the objective so as to increase the amount of light from the marginal portions of the viewing screen reaching a viewer'"'"'s eye located on such optical axis.

Claims

1. A rear-projection viewing screen operative for receiving light incident upon its back side from the objective of a rear-projection projector and forming a corresponding image visible to a human eye viewing the front side of the viewing screen, the rear-projection viewing screen comprising a lens-aperture matrix;

and optical means serving the function of a lens matrix comprised of lens-matrix elements which focus the light from the objective of the rear-projection projector through the apertures of the lens-aperture matrix and furthermore serving the function of a field lens operative for gathering the light emanating from the objective of the projector and deflecting such light in direction toward the optical axis of the objective so as to increase the amount of light from the marginal portions of the viewing screen reaching a viewer'"'"'s eye located on such optical axis.

2. A rear-projection viewing screen as defined in claim 1, wherein the optical means includes a lens matrix and a field lens discrete therefrom.

3. A rear-projection viewing screen as defined in claim 1, wherein the optical means includes a lens matrix and a Fresnel field lens discrete therefrom.

4. A rear-projection viewing screen as defined in claim 1, wherein the optical means includes a lens matrix and a Fresnel field lens at the back side of the viewing screen spaced from the lens matrix a distance between about 0.5 mm and about 10 mm.

5. A rear-projection viewing screen as defined in claim 1, wherein the optical means comprises a lens matrix comprised of lens-matrix zones and a Fresnel field lens comprised of field-lens zones, the field-lens zones being congruent with the lens-matrix zones.

6. A rear-projection viewing screen as defined in claim 1, the optical means including a lens matrix comprised of a plurality of concentric annular lens-matrix zones, the lens matrix being formed of a plurality of radially oriented lens-matrix elements, each annular lens-matrix zone being constituted by a plurality of circumferentially successive ones of the radially oriented lens-matrix elements, the optical means furthermore including a Fresnel field lens comprised of a plurality of concentric annular field-lens zones cooperating with the concentric annular zones of the lens matrix, the lens-aperture matrix being provided with radially extending slit apertures corresponding in size, position and spacing to the size, position and spacing of the radially extending lens-matrix elements.

7. A rear-projection viewing screen as defined in claim 1, wherein the optical means is comprised of a single body of optical material serving both the aforesaid lens-matrix function and the aforesaid field-lens function.

8. A rear-projection viewing screen as defined in claim 1, the optical means being comprised of a single optical structure serving both the aforesaid lens-matrix function and the aforesaid field-lens function, the single optical structure being comprised of a plurality of lens-matrix elements disposed in a rotation-symmetrical arrangement, the lens-matrix elements each having an orientation which is inclined relative to the general plane of the viewing screen, the angle of incline increasing in radially outward direction from one lens-matrix element to the next.

9. A rear-projection viewing screen as defined in claim 8, the lens-matrix elements being arranged in concentric annular zones each containing a pluraliity of lens-matrix elements.

10. A rear-projection viewing screen as defined in claim 8, the lens-matrix elements being arranged in concentric annular zones, each zone being constituted by a single respective annular lens-matrix element, the lens-aperture matrix being provided with a family of concentric annular slit apertures corresponding in size, position and spacing to the size, position and spacing of the annular lens-matrix elements.