Waveguide holographic telltale display

• US 5,341,230 A
• Filed: 12/22/1992
• Issued: 08/23/1994
• Est. Priority Date: 12/22/1992
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Smith, Ronald T.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/995,251
• Time in Patent Office: 609 Days
• Field of Search: 359/1, 359/13, 359/14, 359/15, 359/22, 359/25, 359/34, 359/494, 359/495, 340/479, 340/705
• 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 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G03H 1/0408 Total internal reflection [TIR] holograms, e.g. edge lit or substrate mode holograms

Abstract

A waveguide holographic telltale display for displaying images to a vehicle driver via the vehicle windshield. A light source injects light into the base of a clear inner windshield singlet. A mirror hologram between the inner and outer singlets confines a majority of the injected light to the inner singlet. An image hologram between the windshield singlets diffracts light out to the vehicle driver. A halfwave plate between the image hologram and the inner singlet reduces ghosting and allows the driver to view the images even through polarized sunglasses. IR light is blocked by a tinted outer singlet or a holographic solar coating. The display does not suffer from ambient turn from the sun, and the light source is hidden away from the vehicle dash.

Claims

1. A waveguide holographic telltale display for projecting images via a vehicle windshield comprising inner and outer windshield singlets, comprising:

means for injecting light into the base of said inner windshield singlet;

a telltale image hologram disposed at a predetermined area between said singlets for diffracting light injected into said inner singlet out toward the vehicle driver; and

a holographic mirror disposed between said inner and outer singlets for confining said injected light from entering said outer singlet, and wherein said holographic mirror does not extend over said predetermined area.

2. The display of claim 1 further comprising means for blocking infrared light from entering said vehicle through said windshield.

3. The display of claim 2 wherein said infrared blocking means comprises tinting means for tinting said outer singlet.

4. The display of claim 2 wherein said infrared blocking means comprises a dielectric solar coating applied between said outer and inner singlets.

5. The display of claim 1 wherein said means for injecting light into said singlet base comprises a light source and a light collimating means for collimating the light from said source.

6. The display of claim 5 wherein said means for injecting light into said singlet base further comprises a wedged prism attached to lower singlet base for directing said collimated light into said base.

7. The display of claim 1 wherein said holographic mirror comprises a photopolymer zero-degree reflection hologram.

8. The display of claim 1 further comprising a polyvinyl butyral (PVB) layer disposed between said singlets, and wherein said halfwave plate comprises a polyvinyl alcohol halfwave film disposed between said PVB layer and said holographic mirror and image hologram.

9. The display of claim 1 wherein said holographic mirror and said telltale image hologram are fabricated within a single hologram layer.

10. A waveguide holographic telltale display for projecting images via a vehicle windshield comprising inner and outer windshield singlets, comprising:

means for injecting light into the base of said inner windshield singlet;

a telltale image hologram disposed at a predetermined area between said singlets for diffracting light injected into said inner singlet out toward the vehicle driver;

a holographic mirror disposed between said inner and outer singlets for confining said injected light from entering said outer singlet, and wherein said holographic mirror does not extend over said predetermined area; and

a halfwave plate disposed between said hologram and said inner singlet for reduction of ghost telltale images.

11. The display of claim 10 further comprising means for blocking infrared light from entering said vehicle through said windshield.

12. The display of claim 11 wherein said infrared blocking means comprises tinting means for tinting said outer singlet.

13. The display of claim 11 wherein said infrared blocking means comprises a dielectric solar coating applied between said outer and inner singlets.

14. The display of claim 10 wherein said means for injecting light into said singlet base comprises a light source and a light collimating means for collimating the light from said source.

15. The display of claim 14 wherein said means for injecting light into said singlet base further comprises a wedged prism attached to lower singlet base for directing said collimated light into said base.

16. The display of claim 10 wherein said holographic mirror comprises a photopolymer zero-degree reflection hologram.

17. The display of claim 10 wherein said halfwave plate comprises a polyvinyl alcohol halfwave film.

18. The display of claim 10 further comprising a PVB layer disposed between said singlets, and wherein said halfwave plate comprises a polyvinyl alcohol halfwave film disposed between said PVB layer and said holographic mirror and image hologram.

19. The display of claim 10 wherein said holographic mirror and said telltale image hologram are fabricated within a single hologram layer.

20. A waveguide holographic display, comprising:

a vehicle windshield comprising a clear inner singlet and an outer singlet;

means for injecting light into said inner singlet;

an image hologram disposed at a predetermined display area between said singlets for diffracting light injected into said inner singlet toward a vehicle occupant to form an image;

holographic mirror means disposed between said inner and outer singlets between said light injecting means and said display area for confining said light from entering said outer singlet, wherein light travels within said inner singlet by total internal reflection from said light injecting means to said display area; and

a halfwave layer disposed between said image hologram and said inner singlet for reduction of ghost images.

21. The display of claim 20 further comprising means for blocking infrared light from entering said vehicle through said windshield.

22. The display of claim 21 wherein said infrared blocking means comprises tinting means for tinting said outer singlet.

23. The display of claim 21 wherein said infrared blocking means comprises a dielectric reflective solar coating applied between said outer and inner singlets.

24. The display of claim 21 wherein said infrared blocking means comprises a infrared reflective hologram layer disposed between said singlets.

25. The display of claim 20 wherein said means for injecting light into said singlet comprises a light source and a light collecting means for directing the light from said source toward said singlet.

26. The display of claim 25 wherein said light collecting means further comprises a wedged prism attached to a base of said inner singlet for directing said collected light into said base.

27. The display of claim 25 wherein said light source comprises an incandescent lamp.

28. The display of claim 20 wherein said image hologram comprises a photopolymer zero-degree reflection hologram layer.

30. The display of claim 20 wherein said halfwave layer comprises a polyvinyl alcohol halfwave film.

31. The display of claim 20 wherein said holographic mirror and said image hologram are fabricated within a single hologram layer.

32. The display of claim 20 further comprising an infrared reflective solar control hologram means disposed between said singlets outside said image region, and wherein said infrared reflective hologram means, said image hologram and said mirror hologram are fabricated as a single hologram layer.

33. The display of claim 20 wherein said image comprises a telltale image indicative of vehicle status information.

29. The display of 28 further comprising a polyvinyl butyral (PVB) layer disposed between said halfwave layer and said image hologram.

34. A waveguide holographic display, comprising:

a transparent light waveguide for transmitting light by total internal reflection along the interior of said waveguide from a light input area to an image area, said waveguide having opposed first and second surfaces for creating opposed air/waveguide interfaces which are capable of totally reflecting light incident on said interfaces from within said waveguide;

a light source for injecting light into said waveguide at said light input area, wherein said injected light propagates along the interior of said waveguide from said input area to said image area;

an image hologram disposed against said first waveguide surface at said image area for diffracting light injected into said waveguide toward said second surface at angles to permit said diffracted light to transmit through said second surface and out of said waveguide; and

a halfwave layer disposed adjacent said second surface at said image area for reduction of ghost images.

35. The display of claim 34 wherein said waveguide first surface is disposed adjacent the inner surface of a vehicle windshield, with an air gap between said inner surface and said first surface.

36. The display of claim 34 wherein said light source comprises an incandescent lamp, a reflector and a wedged prism attached to said waveguide at said input area for directing light generated by said lamp into said waveguide.

37. The display of claim 34 wherein said waveguide comprises a transparent plastic waveguide member.