Substrate-guided optical beam expander

• US 20030165017A1
• Filed: 04/11/2003
• Published: 09/04/2003
• Est. Priority Date: 06/05/2000
• Status: Active Grant

• Current Assignee: Lumus Ltd.
• Original Assignee: Lumus Ltd.
• Inventors: Amitai, Yaakov
• Granted Patent: US 6,829,095 B2
• Time in Patent Office: Days
• US Class Current: 359/636
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer

Abstract

The invention provides an optical device, including a light-transmitting substrate, optical means for coupling light into the substrate by total internal reflection, and a plurality of partially reflecting surfaces carried by the substrate, characterized in that the partially reflecting surfaces are parallel to each other and are not parallel to any of the edges of the substrate.

Claims

1. An optical device, comprising:

a light-transmitting substrate;

optical means for coupling light into said substrate by total internal reflection, and

a plurality of partially reflecting surfaces carried by said substrate;

characterized in that said partially reflecting surfaces are parallel to each other and are not parallel to any of the edges of said substrate.

2. The optical device according to claim 1, wherein said optical means is a wave-reflecting surface carried by said substrate.

3. The optical device according to claim 1 wherein said plurality of partially reflecting surfaces couples the light trapped by total internal reflection out of said substrate.

4. The optical device according to claim 2, further comprising means for producing image waves from readout waves, wherein said readout waves and image waves are located on the same side of said substrate.

5. The optical device according to claim 2, further comprising means for producing image waves from readout waves, wherein said readout waves are located on one side of said substrate and said image waves are located on another side of said substrate.

6. The optical device according to claim 2, further comprising means for producing image waves from readout waves, wherein said readout waves are coupled into said substrate through one of its edges.

7. The optical device according to claim 1, wherein the reflectance of said plurality of partially reflecting surfaces is determined to achieve a field of view having uniform brightness.

8. The optical device according to claim 1, wherein the reflectance of said plurality of partially reflecting surfaces is determined to achieve a field of view having predefined brightness.

9. The optical device according to claim 1, wherein the reflectance of each of said partially reflecting surfaces varies locally, to achieve a field of view having predefined brightness.

10. The optical device according to claim 1, wherein the distances between said partially reflecting surfaces are determined to achieve a field of view having predefined brightness.

11. The optical device according to claim 1, further comprising a second plurality of partially reflecting surfaces carried by said substrate, said second plurality of partially reflecting surfaces being parallel to each other and not being parallel to any of the edges of said substrate, and not being parallel to said first plurality of partially reflecting surfaces.

12. The optical device according to claim 11, wherein said second plurality of partially reflecting surfaces changes the direction of propagation of the light coupled in said substrate by total internal reflection.

13. The optical device according to claim 11, wherein the reflectance of said second plurality of partially reflecting surfaces is determined to achieve a field of view having uniform brightness.

14. The optical device according to claim 11, wherein the reflectance of said second plurality of partially reflecting surfaces is determined to achieve a field of view having predefined brightness.

15. The optical device according to claim 1, wherein said substrate is partially transparent, for allowing its see-through operation.

16. The optical device according to claim 1, further comprising an opaque layer attached to the surface of said substrate, for blocking the entrance of light from the external scene.

17. The optical device according to claim 1, further comprising a variable transmittance layer attached to the surface of said substrate, for controlling the brightness of light passing through said device from the external scene.

18. The optical device according to claim 17, wherein the transmittance of said variable transmittance layer is automatically determined according to the brightness of the external scene.

19. The optical device according to claim 2, wherein said plurality of partially reflecting surfaces reflects trapped waves into a direction calculated to reach one eye of an observer.

20. The optical device according to claim 2, wherein said plurality of partially reflecting surfaces reflects trapped waves into a direction calculated to reach both eyes of an observer.

21. The optical device according to claim 20, wherein each of said observer'"'"'s eyes sees only part of the total field of view, and both eyes together see the entire field of view.

22. The optical device according to claim 1, said device combining two different focusings of the same image.

23. The optical device according to claim 1, said device combining two different aspects of the external scene.

24. The optical device according to claim 11, wherein said two pluralities of partially reflecting surfaces are embedded in said substrate in such a way that the lateral dimensions of the light beam emerging from said substrate are larger those of the light beam entering said substrate.

25. The device according to claim 24, wherein the reflectances of said two pluralities of partially reflecting surfaces are set to achieve output waves having uniform intensities.

26. The device according to claim 24, wherein the reflectances of said two pluralities of partially reflecting surfaces are set to achieve output waves having predefined intensities.

27. The optical device according to claim 1, further comprising a virtual retinal display light source.

28. The optical device according to claim 1, further comprising a liquid crystal display (LCD) light source, operating in such a way that the Fourier transform of the desired image is created on the plate of said LCD.

29. The optical device according to claim 1, further comprising an array of light-emitting diodes constituting a light source.

30. The optical device according to claim 29, wherein said light source is coupled into the substrate through its edge.

31. The optical device according to claim 1, wherein said substrate is composed of a plurality of prisms.

32. The optical device according to claim 1, wherein said substrate is composed of a plurality of transparent forms created by injection molding techniques.

33. The optical device according to claim 1, wherein said substrate is composed of a plurality of parallel transparent plates.

34. The optical device according to claim 1, wherein said partially reflecting surfaces are composed of flexible transparent sheet portions coated with optical coatings.

35. The optical device according to claim 1, further comprising air gaps between said partially reflecting surfaces.

36. The optical device according to claim 1, wherein part of the edges or surfaces of said substrate are coated with optical coatings to produce reflective surfaces.

37. The optical device according to claim 1, further comprising at least one half-wavelength plate inserted into the optical pass of said device.

38. The optical device according to claim 1, wherein the reflectance of said plurality of partially reflecting surfaces is effected by Fresnel reflections.

39. The optical device according to claim 1, further comprising an array of at least two reflective surfaces located outside of said light-transmitting substrate.

40. The optical device according to claim 1, further comprising several different substrates combined together to form an optical system.

41. The optical device according to claim 1, wherein said device is embedded inside a spectacle frame.

42. The optical device according to claim 1, wherein said device is embedded inside a cellular phone.