Helmet mounted display projector

• US 4,439,157 A
• Filed: 05/03/1982
• Issued: 03/27/1984
• Est. Priority Date: 05/03/1982
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Lobb, Daniel R., Breglia, Denis R., Spooner, Archer M.
• Primary Examiner(s): Pinkham, Richard C.
• Assistant Examiner(s): Picard, Leo P.
• Application Number:
  US06/374,575
• Time in Patent Office: 694 Days
• Field of Search: 434/35, 434/38, 434/43, 434/44, 358/104, 350/174
• US Class Current: 434/40
• CPC Class Codes: G02B 2027/0154 with movable elements
• CPC Class Codes: G02B 2027/0187 slaved to motion of at least a part of the body of the user, e.g. head, eye
• CPC Class Codes: G02B 2027/0198 System for aligning or maintaining alignment of an image in a predetermined direction
• CPC Class Codes: G02B 27/01 Head-up displays
• 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: G09B 9/307 by helmet-mounted projector or display G09B9/36 takes precedence; optical parts of head-up displays G02B27/01

Abstract

A helmet mounted projector provides offset and frame scanning capabilitiesor a dual channel computer generated image simulation system. The projector receives full color lasers from each channel via a separate optical path, including galvanometer controlled line scan offset mirrors designed to provide eye tracking capabilities, and combines said channels along a single optical axis to provide coordinated frame scanning from the complex image produced by the combined rasters.

Claims

1. An improved apparatus for visual simulation utilizing a domed retroreflective screen, a dual channel computer image generator, with one channel dedicated to a high resolution area of interest and a second channel dedicated to a lower resolution instantaneous field of view, a laser modulation and line scanning system for outputting a plurality of laser line scans in accordance with said computer image generator channels, a plurality of flexible coherent fiber optic bundles for transmitting said line scans, a projector housing operably connected to said fiber optic bundle, and a helmet to be worn on an observer'"'"'s head adapted for mounting said housing thereon, wherein said improvement comprises:

an optical system mounted within said projector housing comprising,

means for generating frame scan for each projected laser line scan, connected to receive transmission from said laser modulation and line scanning system via said fiber bundles, said generating means including means for combining said laser line scans in a single projected frame such that a projected image is formed having a high resolution area of interest bounded by a lower resolution instantaneous field of view;

means for controlling said scan generating means operably connected to receive control signals from said computer image generator; and

means for projecting said laser raster through a wide angle onto said domed screen operably positioned to receive said raster from said scan generating means.

2. An apparatus according to claim 1, wherein said helmet mounted optical system further comprises means for offsetting said line scan along its own length, operably connected to receive said line scan from said fiber optic bundle and receiving control signals from said computer image generator.

3. An apparatus according to claim 2, wherein said helmet mounted optics further comprise:

relay lenses for transmitting said line scan from said fiber optic bundle to said scan generating means, operably positioned to receive said line scan and focus it on said offset means.

4. An apparatus according to claim 1, wherein said projecting means is a complex telescopic lens arrangement configured to form an exit pupil for said rasters immediately in front of said observer'"'"'s forehead.

5. An improved apparatus for visual simulation utilizing a domed retroreflective screen, a dual channel computer image generator, with one channel dedicated to a high resolution area of interest and a second channel dedicated to a lower resolution instantaneous field of view, a laser modulation and line scanning system for outputting a plurality of laser line scans in accordance with said computer image generator channels, a plurality of flexible coherent fiber optic bundles for transmitting said line scans, a projector housing operably connected to said fiber optic bundle, and a helmet to be worn on an observer'"'"'s head adapted for mounting said housing thereon, wherein said improvement comprises:

an optical system mounted within said projector housing comprising,

means for generating frame scan for each projected laser line scan, connected to receive transmission from said laser modulation and line scanning system via said fiber optic bundles;

means for controlling said scan generating means operably connected to receive control signals from said computer image generator;

means for projecting said laser raster through a wide angle onto said domed screen operably positioned to receive said raster from said scan generating means;

means for offsetting said line scan along its own length, operably connected to receive said line scan from said fiber optic bundle and receiving control signals from said computer image generator;

relay lenses for transmitting said line scan from said fiber optic bundle to said scan generating means, operably positioned to receive said line scan and focus it on said offset means;

said offsetting means comprising,

a line offset galvanometer having an extended shaft, receiving control inputs from said computer image generators;

an instantaneous field of view offset mirror mounted on said shaft and positioned to deflect a laser line scan along its own length; and

an ara of interest offset mirror mounted on said shaft and positioned to deflect a laser line scan along its own length in the same manner as said instantaneous field of view offset mirror.

6. An apparatus according to claim 5, wherein said scan generating means comprises:

a plurality of windows having a flat strip mirror at the center thereof, each located at the line scan image of one of said laser line scans;

a plurality of spherical mirrors each associated with one of said windows, positioned so as to receive light reflected from said flat strip mirrors and collimate said light on a path through the associated windows; and

a plurality of frame scan mirrors, movably mounted, for providing frame scan, arranged such that the plurality of laser raster scans thus generated are reflected along a common optical axis, each frame scan mirror receiving a laser line scan from one of said spherical mirrors.

7. An apparatus according to claim 6, wherein said generating control means comprises:

a plurality of galvanometers, each connected to one of said frame scan mirrors for displacing said mirrors in accordance with control signals received from said computer image generator.

8. An apparatus according to claim 6, wherein said plurality of frame scan mirrors include:

a larger area of interest frame scan mirror, mounted to produce a cyclic linear ramp scan to provide controlled offset in the vertical direction, deflecting said area of interest laser raster and said instantaneous field of view laser raster; and

a smaller instantaneous field of view mirror, mounted to produce a cyclic linear ramp scan for producing three-fourths of the frame dimension for said instantaneous field of view raster, deflecting said instantaneous field of view laser raster onto said area of interest scanning mirror.