Wide field of view imaging system

• US 5,706,137 A
• Filed: 08/02/1994
• Issued: 01/06/1998
• Est. Priority Date: 09/22/1992
• Status: Expired due to Term

• Current Assignee: Shawn L. Kelly
• Original Assignee: Shawn L. Kelly
• Inventors: Kelly, Shawn L.
• Primary Examiner(s): NGUYEN, THONG Q
• Application Number:
  US08/284,845
• Time in Patent Office: 1,253 Days
• Field of Search: 359/13-15, 359/32, 359/33, 359/362, 359/364-366, 359/558, 359/563, 359/566-567, 359/572, 359/625-627, 359/629-633, 359/726-732, 345/4-9
• US Class Current: 359/633
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0127 comprising devices increasing the depth of field
• CPC Class Codes: G02B 2027/0143 the two eyes not being equipped with identical nor symmetrical optical devices
• CPC Class Codes: G02B 2027/0152 involving arrangement aiming to get lighter or better balanced devices
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/46 Systems using spatial filters
• CPC Class Codes: G09B 9/307 by helmet-mounted projector or display G09B9/36 takes precedence; optical parts of head-up displays G02B27/01

Abstract

A wide FOV imaging system (10) includes an objective lens (14), a convergent reflective element (18) positioned proximate an intermediate image (16) formed by the objective lens, and a re-imaging lens (20) for re-imaging the intermediate image. The present invention significantly improves image fidelity while minimizing optical components by utilizing a convergent reflective element proximate the intermediate image to reverse the propagation of aberrations produced by the objective lens (14) to, as a result, significantly cancel or reduce the aberrations contributed by the re-imaging lens.

Claims

1. An optical imaging system comprising:

an object imaging means for forming an intermediate image of an object image, said object imaging means producing particular aberrations in the intermediate image;

means for reversing at least some of the aberrations in the intermediate image comprising a convergent reflective medium positioned proximate the intermediate image; and

a re-imaging means for re-imaging the intermediate image reflected by said reflective medium, said re-imaging means producing image aberrations similar to the aberrations produced by said object imaging means, thereby substantially cancelling the aberrations reversed by said reversing means in the re-imaged intermediate image.

2. The system of claim 1 wherein said convergent reflective medium comprises a concave mirror.

3. The system of claim 2 wherein said concave mirror further comprises a Fresnel structure formed on the mirror surface.

4. The system of claim 2 wherein said concave mirror further comprises a concave mirror substrate having a front surface and a back surface provided with a reflective coating, wherein said mirror substrate corrects optical aberrations in said intermediate image produced by said object imaging means, and precorrects for optical aberrations produced by said re-imaging means after said intermediate image is reflected by said reflective coating.

5. The system of claim 1 wherein said convergent reflective medium comprises a flat Fresnel mirror.

6. The system of claim 1 further comprising a beam splitter positioned between said object imaging means and said reflective surface for imaging the intermediate image reflected by said reflective medium to said re-imaging means.

7. The system of claim 1 wherein said means for forming an intermediate image comprises a projection means which produces a modulated scanning light beam to form the intermediate image, and said convergent reflective medium comprises a concave projection screen positioned substantially at the intermediate image.

8. The system of claim 7 wherein the light forming said intermediate image has a predetermined cone of incidence, and said concave projection screen comprises means for redistributing the light incident on any point of the screen surface into a cone of exodus larger than said cone of incidence.

9. The system of claim 1 wherein the light forming said intermediate image has a predetermined cone of incidence, and said means for reversing further comprises means for redistributing the light incident on any point of said convergent reflective medium into a cone of exodus larger than said cone of incidence.