Scene projector

• US 5,245,369 A
• Filed: 10/18/1991
• Issued: 09/14/1993
• Est. Priority Date: 11/01/1989
• Status: Expired due to Fees

• Current Assignee: Aura Systems Inc.
• Original Assignee: Aura Systems Inc.
• Inventors: Lee, Yeon H., Um, Gregory
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Dowling, William C.
• Application Number:
  US07/779,540
• Time in Patent Office: 697 Days
• Field of Search: 353/122, 353/98, 353/99, 353/97, 353/37, 353/31, 353/30, 359/38, 359/70, 359/528, 359/530, 359/546, 358/60, 358/231
• US Class Current: 353/122
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09

Abstract

Optical energy from a broadband source is focused on an aperture in an opaque member. The energy exiting the aperture is received off axis by a parabolic mirror which collimates the energy. The collimated energy is reflected from each planar mirror of an actuated mirror array. The reflected energy from the mirror array is re-reflected to the aperture by the parabolic mirror. The orientation of each planar mirror determines the flux which passes through the aperture or is reflected by a reflective face of the opaque member. The energy reflected from this face which is derived from each mirror corresponds to the flux intensity for a corresponding pixel. This energy may then be focused on a screen to display the scene.

Claims

1. An apparatus to modulate the intensity of a pixel comprising:

a source of optical energy;

an optically opaque member having a first face, a second face, and an aperture therethrough, said second face being optically reflective;

a focusing lens to focus optical energy from said source at said aperture, said energy exiting said aperture along a first propagation path;

a parabolic mirror disposed off-axis in said first propagation path to reflect said energy along a second propagation path;

a planar mirror disposed in said second propagation path of reflect said energy in a return direction along said second path to said parabolic mirror, said planar mirror being associated with the pixel, the energy reflected from said planar mirror being re-reflected by said parabolic mirror toward said aperture, the orientation of said planar mirror determining the flux of the re-reflected energy passing through said aperture and reflected by said second face along a third propagation path wherein the amount of flux reflected by said second face along the third propagation path controls the intensity of said pixel; and

a screen in said third propagation path upon which energy reflected from said second face is focused to display said pixel.

2. An apparatus as set forth in claim 1 further comprising a collimating lens disposed between said second face and said screen to focus energy propagating along said third path of said screen.

3. An apparatus as set forth in claim 1 wherein said aperture is a pinhole.

4. A scene projector to display an image as an array of pixels comprising:

a source of optical energy;

an optically opaque member having a first face, a second face, and an aperture therethrough, said second face being optically reflective;

focusing lens to focus optical energy from said source at said aperture, said energy exiting said aperture along a first propagation path;

a parabolic mirror disposed off-axis in said first propagation path to reflect said energy along a second propagation path;

an actuated mirror array having a plurality of planar mirrors, each of said planar mirrors corresponding to a respective one of said pixels, and each of said mirrors being disposed in said second propagation path to reflect said energy in a return direction along said second path to said parabolic mirror, the energy reflected from each of said planar mirrors being re-reflected by said parabolic mirror toward said aperture, the orientation of each of said planar mirrors determining the flux of the re-reflected energy passing through said aperture and reflected by said second face along a third propagation path wherein the amount of flux reflected by said second face controls the intensity of the respective one of said pixels; and

a screen disposed in said third propagation path upon which energy reflected from said second face is focused to display said pixels.

5. An apparatus as set forth in claim 4 further comprising a collimating lens disposed between said second face and said screen to focus energy propagating along said third path on said screen.

6. An apparatus as set forth in claim 4 wherein said aperture is a pinhole.