Head-mounted projection display system featuring beam splitter and method of making same

• US 5,572,229 A
• Filed: 10/26/1993
• Issued: 11/05/1996
• Est. Priority Date: 04/22/1991
• Status: Expired due to Term

• Current Assignee: Rockwell Collins Simulation and Training Solutions, LLC (Rtx Corporation)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Fisher, Ralph W.
• Primary Examiner(s): SARAS, STEVEN J
• Application Number:
  US08/144,169
• Time in Patent Office: 1,106 Days
• Field of Search: 345/7, 345/8, 345/9, 434/38, 434/40, 434/43, 434/44, 359/13, 359/14, 359/630, 359/631, 340/980, 348/53
• US Class Current: 345/8
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• 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 27/017 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 head-mounted projection display system featuring a beam splitter displays a simulated environment to an observer using a light-weight, low-cost, head-mounted projector and a retro-reflective screen. The display system optically co-locates the projector with the observer'"'"'s eyes for effective use of either curved or flat retro-reflective screens. High screen gain achieved by the head-mounted projection display system makes inexpensive projector sources such as a cathode ray tube feasible. An alternative head-mounted display system also incorporating beam splitters produces an unlimited horizontal field of view, but with limited binocular overlap, while using multiple head-mounted image sources for each eye. A method of providing the head-mounted display system also is disclosed.

Claims

1. A head-mounted projection display system for providing a display to the eyes of an observer, comprising:

a retro-reflective screen; and

a head-mounted projector for use with said retro-reflective screen, further comprising;

a head mount to be worn by the observer;

a head position sensor means coupled to said head mount for providing angular position signals indicative of the angular position of the observer'"'"'s head;

an image generator means providing display signals representative of binocular dynamic displays for the observer and connected to receive said angular position signals to control said display signals;

at least one pair of binocular image means affixed to said head mount and connected to receive said display signals for projecting a pair of binocular images; and

a beam splitter means including a pair of beam splitters affixed to said head mount and positioned at different angles over each of the observer'"'"'s eyes for separately reflecting said pair of binocular images onto said retro-reflective viewing screen, said beam splitter means optically co-locating said pair of binocular images reflected onto said retro-reflective viewing screen and diverging with limited binocular overlap with the eyes of the observer by passing said pair of binocular images from said retro-reflective viewing screen back to the observer through said beam splitter means to provide a substantially unlimited field of view, where a right one of said pair or binocular images appears to the observer as an image projected directly onto a right pupil of the observer'"'"'s eyes and a left one of said pair of binocular images appears to the observer as an image projected directly onto a left pupil of the observer'"'"'s eyes such that a right one of the observer'"'"'s eyes only sees a right one of the pair of binocular images and a left one of the observer'"'"'s eyes only sees a left one of the pair of binocular images.

2. The head-mounted projection display system in accordance with claim 1, wherein said image generator means comprises a cathode ray tube.

3. A head-mounted projection display system in accordance with claim 1, wherein said image generator means provides both a background image and an inset image and includes means for incorporating said background and inset images in each of said binocular dynamic displays.

4. A head-mounted projection display system in accordance with claim 1, wherein said angular position signals are applied to said image generator means to vary said dynamic displays.

5. A head-mounted projection display system in accordance with claim 1, wherein said image generator means includes:

means for providing background and inset images;

means for combining said background and inset images as two display beams; and

means for directing said display beams through said beam splitter to impact said viewing screen.

6. A head-mounted projection display system in accordance with claim 1, wherein said pair of display beams are reflected from said beam splitter to impact said retro-reflective viewing screen to be returned as viewing beams through said beam splitter.

7. A head-mounted projection display system in accordance with claim 1, wherein said angular position signals are applied to said image generator means to vary said dynamic displays.

8. A head-mounted projection display system for use with a retro-reflective screen for providing a display to the eyes of an observer, comprising:

a head mount to be worn by the observer;

a head position sensor means coupled to said head mount for providing angular position signals indicative of the angular position of the observer'"'"'s head;

an image generator means providing display signals representative of binocular dynamic displays for the observer and connected to receive said angular position signals to control said display signals;

at least one pair of binocular image means affixed to said head mount and connected to receive said display signals for projecting a pair of binocular images; and

a beam splitter means including a pair of beam splitters affixed to said head mount wherein said beam splitter means comprises a first and a second beam splitter, said first and second beam splitters inclined in a vertical plane approximately at 45 degrees and oppositely inclined in the horizontal plane approximately at 90 degrees for separately reflecting said pair of binocular images to said retro-reflective viewing screen, said pair of binocular images optically co-located with the eyes of the observer and diverging with limited binocular overlap and further, said beam splitter means passing said pair of binocular images from said retro-reflective viewing screen back to the observer to provide a substantially unlimited field of view.

9. The head-mounted projection display system of claim 8, wherein said image generator means comprises a cathode ray tube.

10. A head-mounted projection display system in accordance with claim 8, wherein said image generator means provides both a background image and an inset image and includes means for incorporating said background and inset images in each of said binocular dynamic displays.

11. A head-mounted projection display system in accordance with claim 8, wherein said angular position signals are applied to said image generator means to vary said dynamic displays.

12. A head-mounted projection display system in accordance with claim 8, wherein said image generator means includes:

means for providing background and inset images;

means for combining said background and inset images as two display beams; and

means for directing said display beams through said beam splitter to impact said viewing screen.

13. A head-mounted projection display system according to claim 8, wherein said pair of display beams are reflected from said beam splitter to impact said retro-reflective viewing screen to be returned as viewing beams through said beam splitter.

14. A head-mounted projection display system according to claim 8, wherein said angular position signals are applied to said image generator means to vary said dynamic displays.