Optical mixer for helmet visual display system

• US 5,243,450 A
• Filed: 04/24/1992
• Issued: 09/07/1993
• Est. Priority Date: 04/25/1991
• Status: Expired due to Fees

• Current Assignee: Sextant Avionique
• Original Assignee: Sextant Avionique
• Inventors: Perbet, Jean-Noel, Gerbe, Jean-Pierre
• Primary Examiner(s): Lerner, Martin
• Application Number:
  US07/873,203
• Time in Patent Office: 501 Days
• Field of Search: 359/13, 359/14, 359/15, 359/409, 359/583, 359/630, 359/632
• US Class Current: 359/13
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0154 with movable elements
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 27/1066 for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view
• CPC Class Codes: G02B 27/141 using dichroic mirrors
• CPC Class Codes: G02B 5/28 Interference filters

Abstract

An optical mixer for use in a helmet visual display system including a light intensifier tube for night vision and a cathode-ray tube for the display of a synthetic image. The mixer includes a swinging glass plate with a spectrally reflective and angularly selective coating. When the angle of the swinging glass plate is changed, the amount of light transmitted through the mixer is changed.

Claims

1. A visual display system for use in a helmet, comprising:

a light intensifier tube for presenting a night vision image;

a cathode-ray tube for presenting a synthetic image;

an d

an optical mixer for mixing said night vision image and said synthetic image, including a pivoting optical plate with a spectrally reflective an angularly selective coating.

2. A visual display system according to claim 1, wherein the coating of the optical plate is made by the deposition of optical thin layers.

3. A visual display system according to claim 2, wherein the coating is a hologram.

4. A visual display system according to any of the claims 1, 2 and 3, wherein the optical plate pivots about an axis passing through a center portion of the optical plate.

5. A visual display system according to claim 1, wherein an optical collimation system is interposed between the mixer and the light intensifier and the cathode ray tubes.

6. A visual display system according to claim 1, wherein pivoting of the optical plate changes an angle of the angularly selective coating with respect to the cathode-ray tube, thereby changing a range of wavelengths from the cathode-ray tube allowed to pass through the angularly selective coating.