Projection screen apparatus

• US 20030038999A1
• Filed: 04/12/2002
• Published: 02/27/2003
• Est. Priority Date: 04/15/1998
• Status: Active Grant

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Walker, Dale S., Knox, Richard M.
• Granted Patent: US 6,788,460 B2
• Time in Patent Office: Days
• US Class Current: 359/15
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• CPC Class Codes: G02B 5/1885 Arranged as a periodic array
• CPC Class Codes: G03B 21/625 Lenticular translucent screens

Abstract

Screen apparatuses are provided which include a first lens or holographic optical element layer and a second mask layer. The first layer substantially collimates image light rays to impinge on the mask layer. The mask layer provides an array or matrix of projecting members. Each of the projecting members receives and focuses the substantially collimated light rays to corresponding focal points. The mask layer includes a mask that blocks light transmission except where openings are located. The openings allow the light focused through the focal joints to substantially pass through the mask to form an image. The screen apparatuses can be advantageously employed in display apparatuses.

Claims

1. A screen apparatus, comprising:

a first layer adapted to substantially collimate light;

a second continuous layer positioned proximate the first layer adapted to receive the substantially collimated light from the first layer and to converge the received substantially collimated light, the second layer comprising an array of bead-like members continuous with the second layer; and

a third layer adjacent the second layer, having openings adapted to receive and to pass the converging light as image light.

2. The screen apparatus of claim 1, wherein the bead-like members comprise an array of surfaces adapted to accept and focus the substantially collimated light.

3. The screen apparatus of claim 1, wherein the third layer comprises a mask portion adapted to substantially block light transmission except at the plurality of openings.

4. The screen apparatus of claim 1, wherein the bead-like members comprise hemispheres.

5. The screen apparatus of claim 1, wherein each of the bead-like members is adapted to substantially focus light at a corresponding focal point.

6. The screen apparatus of claim 5, wherein each focal point is proximate one of the plurality of openings.

7. The screen apparatus of claim 1, wherein the first layer comprises a Fresnel lens.

8. The screen apparatus of claim 1, wherein the first layer comprises discontinuous steps.

9. The screen apparatus of claim 1, wherein the first, second layer and the third layers are spaced apart by a substrate.

10. The screen apparatus of claim 1, wherein the bead-like members comprise an array of spherical sectors.

11. The screen apparatus of claim 1, wherein the first and second layers are spaced apart by an air gap.

12. The screen apparatus of claim 1, wherein the third layer comprises a black adhesive material.

13. The screen apparatus of claim 1, wherein the third layer is adapted to absorb light that is not used as the image light.

14. The screen apparatus of claim 1, wherein the bead-like members are spaced between about 5 and 100 microns apart.

15. The screen apparatus of claim 1, wherein the first layer comprises a holographic optical element.

16. The screen apparatus of claim 1, wherein the first layer, the second layer, and the third layer are comprised in a computer monitor.

17. The screen apparatus of claim 1, wherein the first layer, the second layer, and the third layer are comprised in a television display.

18. The screen apparatus of claim 1, wherein the first layer, the second layer, and the third layer are comprised in a folded optical system.

19. The image projection system of claim 1, wherein regions between the openings are adapted to exclude light that is not the image light.

20. An image projection system comprising:

a projection engine adapted to produce light;

a screen adapted to receive light from the engine, the screen forming a lens layer adapted to collimate the light received from the engine;

the screen comprising a focusing layer adjacent to the lens layer and adapted to receive the collimated light;

the focusing layer forming an array of bead-like members being at least partially rounded, wherein

each of the bead-like members is adapted to focus the collimated light to a corresponding focal point;

the mask layer adapted to partially block light transmission; and

openings in the mask layer, one opening for each focal point adapted to allow the focused light to pass through the mask layer.

21. The image projection system of claim 20, wherein the lens layer comprises a Fresnel lens.

22. The image projection system of claim 20, wherein the lens layer comprises a planar member.

24. The image projection system of claim 20, wherein the bead-like members comprise an array of hemispherically shaped beads.

25. The image projection system of claim 20, wherein the mask layer is spaced apart from the bead-like members.

26. The image projection system of claim 20, wherein the mask layer comprises a substrate.

27. The image projection system of claim 20 wherein the mask layer comprises a thin coating.

28. The image projection system of claim 20, wherein the projection engine and the screen are comprised in a folded optical system.

23. The image projection system of chum 20 wherein the lens layer comprises a collimator.

29. A method of manufacturing a projection screen, comprising:

providing a first layer for collimating light;

providing a second layer;

forming a matrix of convex shaped members continuous with the second layer for focusing the light;

providing a mask layer on the second layer for preventing the transmission of part of the light; and

forming openings in the mask layer at selected positions for allowing passage of another part of the light.

30. The method of claim 29, further comprising positioning the first layer parallel to the second layer.

31. The method of claim 29, wherein the openings are formed with a laser.

32. The method of claim 29 wherein the openings are formed with an excimer laser.

33. The method of claim 29, wherein each of the convex shaped members has a corresponding focal point.

34. The method of claim 29, wherein laser light is directed through the first layer, the second layer and the mask so that the convex shaped members focus the laser light to form the openings.

35. The method of claim 29, wherein the placing comprises positioning the first layer generally parallel to the second layer.

36. The method of claim 29, wherein the placing comprises positioning the first layer spaced apart from second layer.

37. The method of claim 29, wherein the convex shaped members are formed by microreplicating.

38. The method of claim 29, wherein the convex shaped members are formed on the second layer, the convex shaped members having a diameter of between about 5 and 100 microns.

39. The method of claim 29, wherein the openings are formed through the mask layer at selected positions such that light can pass through the openings.

40. The method of claim 29, further comprising forming the mask layer on the second layer.

41. The method of claim 29, wherein the openings are formed about the focal points of the convex shaped members.

42. The method of claim 29, wherein the first layer, the second layer, the convex shaped members, and the mask layer are comprised in a folded optical system.

43. The method of claim 29, wherein providing the first layer comprises providing a holographic optical element.

44. The method of claim 43, further comprising providing an air gap between the holographic optical element and the second layer.

45. The method of claim 43, further comprising substantially minimiizing a gap between the holographic optical element and the second layer for reducing effects of chromatic dispersion.

46. The method of claim 29, further comprising forming the convex shaped members to control magnification of image light differently in vertical and horizontal directions.

47. A method of constructing a projection screen for a display apparatus, comprising:

providing a first layer of material adapted to collimate light;

providing a second layer of material;

forming a matrix of convex shaped members, each having a focal point, on the second layer, the matrix of convex shaped members adapted to focus the light to the focal points;

positioning a mask adapted to prevent transmission of some light transmitted through the second layer in locations comprising the focal points; and

directing the light through the first layer and the matrix of convex shaped members to form openings through the mask at the focal points.

48. The method of claim 47, further comprising positioning the mask at the second layer.

49. The method of claim 47, wherein the light ablates the mask to form the openings.

50. The method of claim 47, wherein the convex shaped members comprise spherical shapes.

51. The method of claim 47, wherein the convex shaped members are formed in a molding process.

52. The method of claim 47, wherein the convex shaped members are formed in an embossing process.

53. The method of claim 47, wherein the convex shaped members comprise cylindrical shapes.

54. The screen apparatus of claim 47, further comprising incorporating the first layer, the second layer, the convex shaped members, and the mask in a folded optical display apparatus.