Modulation of light out of the focal plane in a GLV based projection system

• US 20020145806A1
• Filed: 04/10/2001
• Published: 10/10/2002
• Est. Priority Date: 04/10/2001
• Status: Active Grant

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Amm, David T.
• Granted Patent: US 6,614,580 B2
• Time in Patent Office: Days
• US Class Current: 359/618
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 5/1828 having means for producing variable diffraction controlling the direction of light by means of one or more diffracting elements G02B26/0808; acousto-optical elements G02F1/11, G02F1/33; electro- or magneto-optical diffraction G02F1/292, G02F1/2955
• 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 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

A display apparatus projects an image onto a display screen and includes a grating light valve, a focusing arrangement and a scanning device. The grating light valve is located near but not at a focal plane of a line illumination such that in operation the grating light valve produces real or virtual two dimensional images. The grating light valve is configured such that the modular members on the surface of the grating light valve are neither parallel nor perpendicular to the effective pixel are, thereby arranged diagonally across the pixel area in order to eliminate any imperfections or defects in the line illumination. A seal glass is coupled with the grating light valve and forms an air gap between itself and the grating light valve such that the line illumination must pass through the seal glass and the air gap before reaching the grating light valve. Additionally, an absorbing aperture is affixed to the surface of the seal glass at the focal point of the line illumination in order to further filter background light.

Claims

1. A display apparatus comprising:

a. a grating light valve located near but not at a focal plane of a line illumination such that in operation the grating light valve produces a linear image;

b. a focusing arrangement coupled to the linear image; and

c. a scanning device coupled to the linear image such that in operation the focusing arrangement and the scanning device produce a two dimensional image.

2. The display apparatus as claimed in claim 1 wherein the two dimensional image is a real image.

3. The display apparatus as claimed in claim 1 wherein the two dimensional image is a virtual image.

4. The display apparatus as claimed in claim 1 wherein the grating light valve is configured such that a plurality of modular members of the grating light valve are not parallel with respect to an effective pixel area of the line illumination.

5. The display apparatus as claimed in claim 1 wherein the grating light valve is configured such that the plurality of modular members of the grating light valve are not perpendicular with respect to the effective pixel area of the line illumination.

6. The display apparatus as claimed in claim 1 wherein a seal glass is coupled with the grating light valve such that the line illumination passes through the seal glass before reaching the grating light valve.

7. The display apparatus as claimed in claim 6 wherein the seal glass is coupled with the grating light valve such that an air gap is formed between the seal glass and the grating light valve.

8. The display apparatus as claimed in claim 6 wherein an absorbing aperture is affixed to a surface of the seal glass, said surface of the seal glass positioned at the focal plane of the line illumination.

9. A method of modulating light out of the focal plane in a grating light valve based projection system comprising:

a. positioning a grating light valve near but not at a focal plane of a line illumination such that in operation the grating light valve produces a linear image;

b. coupling a focusing arrangement to the linear image; and

c. coupling a scanning device to the linear image such that in operation the focusing arrangement and the scanning device produce a two dimensional image.

10. The method as claimed in claim 9 further comprising the two dimensional image being a real image.

11. The method as claimed in claim 9 further comprising the two dimensional image being a virtual image.

12. The method as claimed in claim 9 further comprising configuring the grating light valve such that a plurality of modular members of the grating light valve are not parallel with respect to an effective pixel area of the line illumination.

13. The method as claimed in claim 9 further comprising configuring the grating light valve such that the plurality of modular members of the grating light valve are not perpendicular with respect to the effective pixel area of the line illumination.

14. The method as claimed in claim 9 further comprising coupling a seal glass with the grating light valve such that the line illumination passes through the seal glass before reaching the grating light valve.

15. The method as claimed in claim 14 further comprising coupling the seal glass with the grating light valve such that an air gap is formed between the seal glass and the grating light valve.

16. The method as claimed in claim 14 further comprising affixing an absorbing aperture to a surface of the seal glass, said surface of the seal glass positioned at the focal plane of the line illumination.

18. The display system as claimed in claim 17 wherein the two dimensional image is a real image.

19. The display system as claimed in claim 17 wherein the two dimensional image is a virtual image.

20. The display system as claimed in claim 17 wherein the means for modulating is configured such that a plurality of modular members of the means for modulating are not parallel with respect to an effective pixel area of the line illumination.

21. The display system as claimed in claim 17 wherein the means for modulating is configured such that the plurality of modular members of the means for modulating are not perpendicular with respect to the effective pixel area of the line illumination.

22. The display system as claimed in claim 17 further comprising means for sealing coupled with the means for modulating such that the line illumination passes through the means for sealing before reaching the means for modulating.

23. The display system as claimed in claim 22 wherein the means for sealing is coupled with the means for modulating such that an air gap is formed between the means for sealing and the means for modulating.

24. The display system as claimed in claim 22 further comprising means for absorbing affixed to a surface of the means for sealing, said surface of the means for sealing positioned at the focal plane of the line illumination.

26. The display apparatus as claimed in claim 25 wherein the two dimensional image is a real image.

27. The display apparatus as claimed in claim 25 wherein the two dimensional image is a virtual image.

29. The light valve as claimed in claim 28 wherein the focusing arrangement produces a two dimensional image, where the two dimensional image is a real image.

30. The light valve as claimed in claim 28 wherein the focusing arrangement produces a two dimensional image, where the two dimensional image is a virtual image.

31. The light valve as claimed in claim 28 wherein the light modulator is configured such that a plurality of modular members of the light modulator are not parallel with respect to an effective pixel area of the illumination.

32. The light valve as claimed in claim 28 wherein the light modulator is configured such that the plurality of modular members of the light modulator are not perpendicular with respect to the effective pixel area of the illumination.

33. The light valve as claimed in claim 28 wherein a seal glass is coupled with the light modulator such that the illumination passes through the seal glass before reaching the light modulator.

34. The light valve as claimed in claim 33 wherein the seal glass is coupled with the light modulator such that an air gap is formed between the seal glass and the light modulator.

35. The light valve as claimed in claim 33 wherein an absorbing aperture is affixed to a surface of the seal glass, said surface of the seal glass positioned at the focal plane of the illumination.

17. A display system comprising:

a. means for modulating light located near but not at a focal plane of a line illumination such that in operation the means for modulating produces a linear image;

b. means for focusing coupled to the linear image; and

c. means for scanning coupled to the linear image such that in operation the means for focusing and the means for scanning produce a two dimensional image.

25. A display apparatus for modulation of light out of the focal plane in a grating light valve based projection system comprising:

a. a grating light valve located near but not at a focal plane of a line illumination and configured such that a plurality of modular members of the grating light valve are neither parallel nor perpendicular with respect to an effective pixel area of the line illumination, said grating light valve positioned such that in operation the grating light valve produces a linear image;

b. a focusing arrangement coupled to the linear image;

c. a scanning device coupled to the linear image such that in operation the focusing arrangement and the scanning device produce a two dimensional image;

d. a seal glass coupled with the grating light valve such that the line illumination passes through the seal glass before reaching the grating light valve and such that an air gap is formed between the seal glass and the grating light valve; and

e. an absorbing aperture affixed to a surface of the seal glass, said surface of the seal glass positioned at the focal plane of the line illumination.

28. A light valve comprising:

a. a light modulator configured to receive an illumination from an illumination source such that the illumination source is not focused on the light modulator; and

b. a focusing arrangement coupled to the illumination source such that the focusing arrangement focuses the illumination onto a target.