Dispersion-compensated windshield hologram virtual image display

• US 4,981,332 A
• Filed: 06/29/1989
• Issued: 01/01/1991
• Est. Priority Date: 06/29/1989
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Smith, Ronald T.
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Parsons, David R.
• Application Number:
  US07/373,962
• Time in Patent Office: 551 Days
• Field of Search: 350/3.7, 350/3.81, 350/3.72, 350/174, 350/3.85, 350/3.6, 350/3.75
• US Class Current: 359/13
• CPC Class Codes: G02B 2027/0109 comprising details concerning the making of holograms
• CPC Class Codes: G02B 2027/0116 comprising devices for correcting chromatic aberration
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 27/0103 comprising holographic elements

Abstract

A virtual image display including an image hologram, a dispersion compensating hologram for providing playback illumination to the image hologram, and an illumination source for providing playback illumination to the dispersion compensating hologram.

Claims

1. A virtual image display comprising:

an image hologram having a plurality of image components recorded therein, said image components configured to produce virtual image components at different virtual image planes;

a source of illumination;

compensating means responsive to said source illumination for providing to said image hologram playback illumination that is chromatically predispersed so as to compensate for the chromatic dispersion of said image hologram, said image hologram producing in response to said playback illumination virtual image components of said recorded image components which are relatively sharp over a depth of field greater than would be produced without said compensation means.

2. The virtual image display of claim 1 wherein said compensating means comprises a dispersing hologram.

3. The virtual image display of claim 1 wherein said image hologram produces a virtual image that is displaced from said image hologram.

4. The virtual image display of claim 1 wherein said illumination is a spectrally broadband source.

5. The virtual image display of claim 1 wherein said image hologram comprises a reflection hologram.

6. The virtual image display of claim 1 wherein said virtual image components are overlapping.

7. A virtual image display comprising:

an image hologram having an image recorded therein;

a source of spectrally broadband illumination;

a dispersing hologram responsive to said source illumination for providing to said image hologram playback illumination that is chromatically predispersed so as to compensate for the chromatic dispersion of said image hologram, said image hologram producing in response to said playback illumination a virtual image of said recorded image having a depth of field greater than would be produced without said compensation means.

8. The virtual image display of claim 7 wherein said image hologram produces a virtual image that is displaced from said image hologram.

9. The virtual image display of claim 7 wherein said image hologram produces a virtual image having image components located at different virtual image planes.

10. The virtual image display of claim 9 wherein said virtual image components are overlapping.

11. A virtual image display for a vehicle having a windshield, comprising:

an image reflection hologram having an image recorded therein and supported by the vehicle windshield for producing pursuant to playback illumination a virtual image viewable by the operator of the vehicle;

a source of illumination

compensating means responsive to said source illumination for providing to said image hologram playback illumination that is chromatically predispersed so as to compensate for the chromatic dispersion of said image hologram, said image hologram producing in response to said playback illumination a virtual image of said recorded image having a depth of field greater than would be produced without said compensation means.

12. The virtual image display of claim 11 wherein said compensating means comprises a dispersing hologram.

13. The virtual image display of claim 11 wherein said image hologram produces a virtual image that is displaced from said image hologram.

14. The virtual image display of claim 11 wherein said image hologram produces a virtual image having image components located at different image planes.

15. The virtual image display of claim 14 wherein said virtual image components are overlapping.

16. The virtual image display of claim 11 wherein said illumination is a spectrally broadband source.