Virtual image display apparatus

• US 4,294,515 A
• Filed: 03/23/1979
• Issued: 10/13/1981
• Est. Priority Date: 03/23/1979
• Status: Expired due to Term

• Current Assignee: BMCO Incorporated Edina MN
• Original Assignee: Arthur Kaufman
• Inventors: Kaufman, Arthur
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US06/023,160
• Time in Patent Office: 935 Days
• Field of Search: 350/174, 350/291, 350/296, 350/293, 350/298, 358/250, 358/238, 358/239, 358/185, 352/4, 353/98, 353/99, 272/8 M, 272/8.5, 272/13, 356/251, 356/252, 356/254, 356/255
• US Class Current: 353/29
• CPC Class Codes: B60K 2360/334 Projection means
• CPC Class Codes: B60K 2370/334 Projection means
• 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 2027/0169 Supporting or connecting means other than the external walls
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 27/141 using dichroic mirrors
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G09F 19/16 involving the use of mirrors

Abstract

A virtual image display device for alpha-numeric and pictorial information. A concave spherical mirror segment magnifies and reflects an image from an image source. The image source is mounted between the focus of the mirror and the said mirror and parallel to its optical axis. The virtual image thereby formed is visible to the viewer in front of the mirror.

In related embodiments, the concave mirror segment can be made partially reflective and placed in front of a camera lens to allow a camera to photograph through it. A planar mirror can also be included to fold the light path of the display and thereby reduce the size of the apparatus.

Claims

1. A virtual image display apparatus comprising a mirror in the shape of a substantially concave segment of a hemisphere said spherical mirror having an optical axis and a focus, an image source means for said mirror segment, and an image display face on said image source disposed substantially perpendicular to said optical axis but located off said axis and substantially on the same side of the axis as the line of sight of an observer and between said focus and said mirror segment.

2. A virtual image display apparatus according to claim 1 wherein said mirror segment is a partially reflective mirror.

3. A virtual image display apparatus according to claim 1 wherein a partially reflective planar mirror is angularly positioned between said mirror segment and said image source to receive light reflected by the mirror segment and direct it in a path across the optical axis of said mirror segment.

4. A virtual image display apparatus according to claim 1 wherein a fully reflective mirror is placed substantially in front of said image source laterally displaced from the concave mirror segment and substantially parallel to the light emitting image display face of said image source and wherein the said image display face is directed away from said mirror segment.

5. A virtual image display apparatus according to claim 1 wherein said image source means is a cathode ray tube.

6. A virtual image display apparatus according to claim 1 wherein said image source means is a thin film cathode ray tube.

7. A virtual image display apparatus according to claim 1 wherein said image source means is a liquid crystal display apparatus.

8. A virtual image display apparatus according to claim 1 wherein said image source means is a light emitting diode array.

9. A virtual image display device according to claim 1 wherein said image source means is an electroluminescent panel.

10. A virtual image display device according to claim 1 wherein said image source means is a tungsten filament projector.

11. A virtual image display device according to claim 1 wherein said image source means is a gaseous plasma discharge cell.

12. A virtual image display device according to claim 1 wherein said image source is a back illuminated film or transparency.

13. A virtual image display device according to claim 1 wherein said image source means is a front illuminated partially reflecting original.

14. A virtual image display device according to claim 1 wherein said mirror segment is dichroic.

15. A virtual image display apparatus according to claim 3 wherein said partially reflective planar mirror is dichroic.

16. A virtual image display apparatus according to claim 1 wherein said image source is slidably carried by a support located between said mirror segment and said focus, whereby said image source may be moved so as to decrease or increase the degree to which its image is magnified by the virtual image display apparatus without changing the vertical position of the virtual image with respect to the mirror segment.

17. A virtual image display apparatus according to claim 4 in which the fully reflective mirror is a curved front surface mirror.

18. A virtual image display apparatus according to claim 4 in which the fully reflective mirror is a planar mirror.