Polarizing optical system
There is provided an optical system, including a light-transmitting substrate having at least two major surfaces parallel to each other and edges, and an optical device for coupling light into the substrate by total internal reflection. The device includes a polarization sensitive reflecting surface.
1. An optical system, comprising:
at least one display light source for producing light waves;
a light-transmitting substrate having at least two major external surfaces parallel to each other, edges and at least one partially reflecting surface located in the substrate; and
an optical device for coupling light waves into the substrate to effect total internal reflection of the coupled-in light waves between the two major external surfaces of the substrate, the optical device including a polarization sensitive beamsplitter, a reflecting surface and a retardation plate, the light waves passing at least once through the beamsplitter, reflected at least once from the beamsplitter, reflected at least once from the reflecting surface and passing at least once through the retardation plate prior to being coupled into the substrate, the beamsplitter oriented such that the coupled-in light waves are directly reflected from the beamsplitter at an oblique angle with respect to the external surfaces, without any further reflection, to be trapped inside the substrate by total internal reflection, the light waves reflected at least once by one of the external major surfaces of the substrate before being coupled-out of the substrate by the partially reflecting surface.
2. The optical system according to claim 1 , further comprising an array of said at least one partially reflecting surface located in said substrate which is non-parallel to said major surfaces of the substrate.
3. The optical system according to claim 2 , wherein said beamsplitter is parallel to said array of partially reflecting surfaces.
4. The optical system according to claim 1 , wherein said beamsplitter for coupling light is embedded inside said light-transmitting substrate.
5. The optical system according to claim 1 , wherein said beamsplitter is non-parallel to said major surfaces of the substrate.
6. The optical system according to claim 1 wherein the beam splitter reflects s-polarized light waves and transmits p-polarized light waves.
7. The optical system according to claim 1 , wherein the beam splitter reflects p-polarized light waves and transmits s-polarized light waves.
8. The optical system according to claim 1 wherein the beam splitter comprises a polarization sensitive thin film dielectric coating.
9. The optical system according to claim 1 wherein the beam splitter comprises a wire grid polarizer.
10. The optical system according to claim 1 , wherein said retardation plate comprises a quarter-wave retardation member located next to one of said major surfaces.
11. The optical system according to claim 10 , where said reflecting surface is located next to said quarter-wave retardation member.
12. The optical system according to claim 11 , wherein said reflecting surface is cemented to said quarter-wave retardation member.
13. The optical system according to claim 11 , wherein said reflecting surface is coated on a back side of said quarter-wave retardation member.
14. The optical system according to claim 11 , wherein said quarter-wave retardation member is a film laminated on a front surface of said reflecting surface.
15. The optical system according to claim 10 , further comprising a converging lens located next to said quarter-wave retardation member.
16. The optical system according to claim 15 , wherein a back surface of said converging lens is coated with a reflecting coating serving as said reflecting surface.
17. The optical system according to claim 15 , wherein said converging lens is a plano-convex lens.
18. The optical system according to claim 10 , further comprising a converging lens located next to said quarter-wavelength retardation member.
19. The optical system according to claim 18 , wherein said converging lens is a plano-convex lens.
20. The optical system according to claim 18 , wherein a back surface of said converging lens is coated with a reflective coating serving as said reflecting surface.
21. The optical system according to claim 18 , wherein said converging lens is optically attached to said quarter-wave retardation member.
22. The optical system according to claim 18 , wherein said converging lens is a collimating lens.
23. The optical system according to claim 1 , wherein said light waves emerging from said display source enter said light-transmitting substrate through one of said major surfaces.
24. The optical system according to claim 23 , further comprising an optical module which collimates said light waves.
25. The optical system according to claim 24 , wherein said collimating optical module comprises a folding prism.
26. The optical system according to claim 25 , further comprising at least one polarizer beamsplitter embedded inside said folding prism.
27. The optical system according to claim 25 , further comprising a quarter-wave retardation member located next to said folding prism.
28. The optical system according to claim 25 , further comprising at least one converging lens located next to said retardation plate.
29. The optical system according to claim 28 , wherein a back surface of said at least one converging lens is coated with a reflective coating serving as said reflecting surface.
30. The optical system according to claim 23 , wherein said light waves are linearly polarized.
31. The optical system according to claim 23 , wherein said light waves are unpolarized.