Projected image blending for multiple images

• US 6,017,123 A
• Filed: 07/07/1997
• Issued: 01/25/2000
• Est. Priority Date: 01/29/1996
• Status: Expired due to Term

• Current Assignee: JVC Kenwood Corporation
• Original Assignee: JVC Americas Corporation (JVC Kenwood Corporation)
• Inventors: Reinsch, Stephen J., Bleha, William P.
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US08/889,043
• Time in Patent Office: 932 Days
• Field of Search: 353/30, 353/84, 353/94, 353/97, 353/122, 348/745, 348/806, 348/756, 348/779, 349/5, 349/7, 349/8, 359/888, 359/890
• US Class Current: 353/30
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/12 Picture reproducers H04N9/11 takes precedence
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026

Abstract

A projection system includes first and second light valve projectors which project a composite image onto a screen by overlapping the first and second images in an overlap region. Each projector includes a light source, a light valve for reflecting or transmitting image light, a condensing lens for directing light from the light source to the light valve, and a projection lens. An improved light valve projector includes a blending device, associated with the first and second light valve projectors and being located in the path of the light between the light valve and the projection lens, the light source and the condensing lens, or the projection lens and the screen. The blending device smoothes off-state and on-state illumination levels in the overlap region without reducing the contrast ratio of said light valve projector. The blending device includes physical devices such as filters, solid masks, and/or a combination thereof as a substitute for electronic blending. By physically blending off-state illumination levels, the present invention avoids loss of contrast ratio associated with electronic blending.

Claims

1. In a projection system including first and second light valve projectors which project a composite image onto a screen by overlapping first and second images in an overlap region, each projector including a light source, a light valve for reflecting or transmitting image light, a condensing lens for directing light from said light source to said light valve, and a projection lens, an improved fight valve projector comprising:

blending means, associated with said first and second light valve projectors and being located in the path of said light between one of said light valve and said projection lens, said light source and said condensing lens, and said projection lens and said screen, said blending means for smoothing off-state and on-state illumination levels in said overlap region without reducing the contrast ratio of said light valve projector, said blending means comprising a mask having a tapered edge, said mask being located in the path of said light.

2. The improved light valve projector of claim 1 wherein said light valve is a reflective light valve and said projection system further includes a polarization beam splitter.

3. The improved light valve projector of claim 1 wherein said blending means is located in a focus position at or adjacent an image plane which said condensing lens focuses onto said light valve.

4. The improved light valve projector of claim 3 wherein said blending means comprises:

a clear substrate; and

a coating formed thereon.

5. The improved light valve projector of claim 4 wherein said coating is a neutral density coating.

6. The improved light valve projector of claim 5 wherein the thickness of said neutral density coating increases from a point between opposing edges to at least one of the said opposing edges.

7. The improved light valve projector of claim 6 wherein the thickness of said neutral density coating increases continuously.

8. The improved light valve projector of claim 6 wherein the thickness of said neutral density coating increases in steps.

9. The improved light valve projector of claim 1 wherein said light valve is a reflective liquid crystal light valve.

10. The improved light valve projector of claim 1 wherein said blending means is located in a position at or adjacent an image plane which said projection lens focuses onto said screen.

11. The improved light valve projector of claim 10 wherein said blending means comprises:

a clear substrate; and

a coating formed thereon.

12. The improved light valve projector of claim 11 wherein said coating is a neutral density coating.

13. The improved light valve projector of claim 10 wherein said blending means is located adjacent said light valve.

14. The improved light valve projector of claim 1 wherein said blending means is located in a non-focus position between said light valve and said projection lens.

15. The improved light valve projector of claim 1 wherein said blending means comprises a mask located in a non-focus position between said condensing lens and an image plane which said condensing lens focuses onto said light valve.

16. The improved light valve projector of claim 15 wherein said mask has a tapered edge located in the path of said light.

17. The improved light valve projector of claim 14 wherein said mask comprises a glass substrate having a thin film coating formed on a surface thereof.

18. The improved light valve projector of claim 1 wherein said blending means is located in a non-focus position between said projection lens and said screen.

19. The improved light valve projector of claim 18 wherein said blending means comprises:

a first neutral density filter; and

a second neutral density filter located adjacent said first neutral density filter.

20. The improved light valve projector of claim 19 wherein said blending means further comprises a mask located adjacent said second neutral density filter and having a tapered edge located in the path of said light.

21. The improved light valve projector of claim 20 wherein said mask includes a tapered edge.

22. The improved light valve projector of claim 20 wherein said first and second neutral density filters and said mask are situated adjacent to each other.

23. The improved light valve projector of claim 20 wherein inner edges of said first and second neutral density filters and said mask are positioned in the path of said light.

24. The improved light valve projector of claim 23 wherein said blending means further comprises a second mask located in a non-focus position between said condensing lens and an image plane which said condensing lens focuses onto said light valve.

25. The improved light valve projector of claim 24 wherein said second mask has a taped edge located in the path of said light.

26. A projection system, comprising:

an image projector that projects a composite image formed from a plurality of overlapping images;

a projection screen positioned in an image plane that displays the projected composite image;

a plurality of light blending devices each positioned between the image projector and the screen such that one image of the plurality of projected images is incident thereon, and each having a body with a substantially continuous outer periphery, an input surface that receives the image, and an exit surface that passes the image, the body having at least a portion thereof that varies in thickness between the input and exit surfaces to adjust an illumination level in a region of the image that overlaps with a region of one or more images in the plurality of images such that the composite image displayed on the projection screen is seamless;

a first filter including a body with input and exit surfaces, and first and second opposing edges, the exit surface of the filter being positioned adjacent the input surface of one of the light blending devices such that the first edge is offset from the periphery of the light blending device to attenuate light passing therethrough; and

a second filter including a body with input and exit surfaces, and first and second opposing edges, the exit surface of the filter being positioned adjacent the input surface of the first filter such that the first opposing edge of the second filter is offset from the first opposing edge of the first filter to attenuate light passing therethrough.

27. The projection system according to claim 26 wherein the first and second filters are neutral density filters.

28. The projection system according to claim 26 wherein the light blending devices are graded density filters, each comprising a transparent substrate and a color-neutral density coating of varying thickness disposed thereon.

29. The projection system according to claim 26 wherein the light blending devices are solid metal masks.

30. The projection system according to claim 26 wherein at least one of the light blending devices is formed of a first and a second filter, each including a body, input and exit surfaces, and first and second opposing edges, with the second filter exit surface being positioned adjacent the input surface of the first filter such that the first opposing edge of the second filter is offset from the first opposing edge of the first filter to attenuate light passing therethrough.

31. The projection system according to claim 30 wherein the first and second filters are neutral density filters.

32. The projection system according to claim 26, wherein the portion of the body that varies in thickness in each of the plurality of light blending devices smooths off-state and on-state illumination levels in a region of the image that overlaps with one or more of the other images.

33. The projection system according to claim 26, wherein each of the plurality of light blending devices is tillable relative to the image plane to minimize reflection from the device transmitted to the projection screen.

34. The projection system according to claim 26, wherein the image projector comprises a plurality of light valve projectors, each of the plurality of light valve projectors comprising:

a light source that generates source light;

a lens that focuses the source light;

a light valve that modulates the source light focused by the lens with image data supplied to the image projector; and

a projection lens that projects the source light modulated by the light valve onto the projection screen.

35. The projection system according to claim 34 wherein each of the light blending devices is positionable in a focus position between the light source and the lens.

36. The projection system according to claim 34 wherein each of the light blending devices is positionable in a non-focus position between the light source and the lens.

37. The projection system according to claim 34 wherein each of the light blending devices is positionable in a focus position between the light valve and the projection lens.

38. The projection system according to claim 34 wherein each of the light blending devices is positionable in a non-focus position between the light valve and the projection lens.

39. The projection system according to claim 34 wherein each of the light blending devices is positionable in a non-focus position between the projection lens and the projection screen.

40. The projection system according to claim 26 wherein each of the light blending devices increases in thickness from a central portion of the body to the outer periphery.

41. The projection system according to claim 26 wherein each of the light blending devices decreases in thickness from a central portion of the body to the outer periphery.

42. A blending device for a projector in a composite image projection system, comprising:

a body including a substantially continuous periphery;

an input surface defined on the body that receives light generated by the projection system;

an exit surface defined on the body opposite the input surface;

the body including at least a portion thereof that varies in thickness between the input and exit surfaces to attenuate the light generated by the projection system such that when the light is combined with light from other system projectors, a seamless composite image is formed;

a first filter having a body, input and exit surfaces, and first and second opposing edges, with the first filter exit surface being positioned adjacent the input surface such that the first edge is offset from the substantially continuous periphery to attenuate light passing therethrough; and

a second filter having a body, input and exit surfaces, and first and second opposing edges, with the second filter exit surface being positioned adjacent the input surface of the first filter such that the first opposing edge of the second filter is offset from the first opposing edge of the first filter to attenuate light passing therethrough.

43. The blending device according to claim 42, wherein the blending device is a clear substrate with a color-neutral, variable-thickness density coating.

44. The blending device according to claim 42, wherein the blending device is a solid metal mask.

45. The blending device according to claim 42, wherein the first and second filters are neutral density filters.

46. The blending device according to claim 42, wherein the blending device is formed of a first and second filter, each having a body, input and exit surfaces, and first and second opposing edges, with the second filter exit surface being positioned adjacent the input surface of the first filter such that the first opposing edge of the second filter is offset from the first opposing edge of the first filter to attenuate light passing therethrough.

47. The blending device according to claim 46, wherein the first and second filters are neutral density filters.

48. The blending device according to claim 42, wherein the thickness between the input and exit surfaces increases from a central portion of the body to the periphery of the blending device.

49. The blending device according to claim 42 wherein the thickness between the input and exit surfaces decreases from a central portion of the body to the periphery of the blending device.