Anamorphic illumination of micro-electromechanical display devices employed in multimedia projectors

Abstract

Micro-electromechanical display device (“MDD”)-based multimedia projectors ( 90, 120 ) of this invention employ an arc lamp ( 32 ), a color modulator ( 42 ), and anamorphic illumination systems ( 94, 121 ) for optimally illuminating a MDD ( 50, 76 ) to improve projected image brightness. MDDs employ off-axis illumination wherein incident and reflected light bundles are angularly separated about a hinge axis ( 78, 110 ) and the MDD is illuminated by the anamorphic illumination systems of this invention having a slow f/# parallel to the hinge axis and a faster f/# perpendicular to the hinge axis. The resulting anamorphic light bundles ( 86, 88, 112, 114 ) illuminate and reflect more light into and off the MDD and through a fast f/# projection lens.

I claim: 
     
       1. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to a first of the hinge axes and at a substantially faster second f/number parallel to the first hinge axis. 
 
     
     
       2. The apparatus of  claim 1  in which the illumination source further includes an arc lamp and a reflector. 
     
     
       3. The apparatus of  claim 1  in which the first f/number is about twice the second f/number. 
     
     
       4. The apparatus of  claim 1  in which the first hinge axis is parallel to an edge margin of the MDD and the anamorphic optical device includes an anamorphic light tunnel having orthogonal height, width, and length dimensions, an input aperture with a first height and a first width for receiving the light rays, and an output aperture having a second height and a second width for forming the anamorphic incident illumination bundle. 
     
     
       5. The apparatus of  claim 4  in which the first height and the second height are substantially the same, and the first width is about twice the second width. 
     
     
       6. The apparatus of  claim 4  in which the MDD and the output aperture each have substantially the same width-to-height ratio. 
     
     
       7. The apparatus of  claim 1  in which the anamorphic optical device includes a collimating lens system, first and second flyseye lenslet arrays, and an imaging lens system. 
     
     
       8. The apparatus of  claim 7  in which the MDD has an MDD aspect ratio and the first flyseye lenslet array includes an array of first lenslets each having a lenslet aspect ratio that substantially matches the MDD aspect ratio. 
     
     
       9. The apparatus of  claim 8  in which the anamorphic incident illumination bundle illuminates the MDD at an oblique angle and the first lenslets have a rhomboid shape that compensates for the oblique angle. 
     
     
       10. The apparatus of  claim 7  in which the first and second flyseye lenslet arrays include arrays of respective first and second lenslets, the first lenslets each having a center of curvature that is offset to steer the light rays toward corresponding ones of the second lenslets. 
     
     
       11. The apparatus of  claim 7  in which the second lenslets have centers of curvature that are centered in each lenslet for optimal light transmission efficiency. 
     
     
       12. The apparatus of  claim 7  in which the first and second flyseye lenslet arrays are tilted about the optical axis such that the anamorphic incident illumination bundle has an elliptical cross section having a major axis that is substantially aligned with the first hinge axis. 
     
     
       13. The apparatus of  claim 7  in which the imaging lens system images the first flyseye lenslet array onto the MDD, thereby producing the anamorphic incident light bundle. 
     
     
       14. In a multimedia projector, a method of operation comprising:
 generating light rays from an illumination source of the multimedia projector; 
 receiving and shaping the generated light rays by an anamorphic optical device of the multimedia projector to form an anamorphic incident illumination bundle with a substantially elliptical cross section to illuminate a micro-electromechanical display device (MDD), the MDD having a plurality of micromirrors, each micromirror having a hinge axis, the substantially elliptical cross section of incident illumination bundle having a first axis perpendicular to a first of the hinge axes, and a second axis parallel to the first hinge axis, the second axis being longer than the first axis. 
 
     
     
       15. The method of  claim 14 , in which the anamorphic incident illumination bundle illuminates the MDD at a first f/number perpendicular to the first hinge axis and at a substantially faster second f/number parallel to the first hinge axis. 
     
     
       16. The method of  claim 15 , in which the first f/number is about twice the second f/number. 
     
     
       17. The method of  claim 14 , in which generating light rays from an illumination source further includes generating light rays from an arc lamp and reflecting light rays with a reflector positioned substantially adjacent to arc lamp. 
     
     
       18. The method of  claim 14 , in which the anamorphic optical device includes an anamorphic light tunnel having orthogonal height, width and length dimensions, an input aperture with a first height and a first width to receive the light rays, and an output aperture having a second height and a second width to form the anamorphic incident illumination bundle. 
     
     
       19. In a multimedia projector, an apparatus comprising:
 an illumination source generating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and shaping an anamorphic incident illumination bundle with a substantially elliptical cross section to illuminate a micro-electromechanical display device (MDD), the MDD having a plurality of micromirrors, each micromirror having a hinge axis, the substantially elliptical cross section of incident illumination bundle having a first axis perpendicular to a first of the hinge axes, and a second axis parallel to the first hinge axis, the second axis being longer than the first axis. 
 
     
     
       20. The apparatus of  claim 19 , in which the anamorphic optical device includes an anamorphic light tunnel having orthogonal height, width, and length dimensions, an input aperture with a first height and a first width for receiving the light rays, and an output aperture having a second height and a second width for forming the anamorphic incident illumination bundle. 
     
     
       21. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to the respective hinge axes and at a substantially faster second f/number parallel to the respective hinge axes, wherein 
 the anamorphic optical device includes an anamorphic light tunnel having an input aperture and an output aperture, and at least one diagonal measurement of the input aperture is longer than at least one diagonal measurement of the output aperture. 
 
     
     
       22. The apparatus of claim 21 in which an aspect ratio of the input aperture is different from an aspect ratio of the output aperture. 
     
     
       23. The apparatus of claim 21 in which the input aperture is larger than the output aperture. 
     
     
       24. The apparatus of claim 21 in which the anamorphic optical device further includes a field lens, the light rays from the anamorphic light tunnel enter the field lens. 
     
     
       25. The apparatus of claim 21 in which the input aperture is defined by an input width and an input height, and the output aperture is defined by an output width and an output height, the input width being configured to be greater than the output width. 
     
     
       26. The apparatus of claim 21 in which the anamorphic optical device increases an illumination angle of the light rays exiting the output aperture of the anamorphic light tunnel along the respective hinge axes of the MDD more than an illumination angle of the light rays entering the input aperture of the anamorphic light tunnel along the respective hinge axes. 
     
     
       27. The apparatus of claim 26 in which the anamorphic optical device increases an illumination angle of the light rays so that an entrance pupil of the projection lens accepts the illumination angle of the light ray via the MDD along the respective hinge axes of the MDD without overfilling the entrance pupil with the light bundle. 
     
     
       28. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to a first of the respective hinge axes and at a substantially faster second f/number parallel to the first hinge axis, wherein 
 the anamorphic optical device includes an anamorphic light tunnel having an input aperture and an output aperture, and an aspect ratio of the input aperture is different from an aspect ratio of the output aperture. 
 
     
     
       29. The apparatus of claim 28 in which the input aperture is larger than the output aperture. 
     
     
       30. The apparatus of claim 28 in which the anamorphic optical device further includes a field lens, the light rays from the anamorphic light tunnel enter the field lens. 
     
     
       31. The apparatus of claim 28 in which the input aperture is defined by an input width and an input height, and the output aperture is defined by an output width and an output height, the input width being configured to be greater than the output width. 
     
     
       32. The apparatus of claim 28 in which the anamorphic optical device increases an illumination angle of the light rays exiting the output aperture of the anamorphic light tunnel along the respective hinge axes of the MDD more than an illumination angle of the light rays entering the input aperture of the anamorphic light tunnel along the respective hinge axes. 
     
     
       33. The apparatus of claim 32 in which the anamorphic optical device increases an illumination angle of the light rays so that an entrance pupil of the projection lens accepts the illumination angle of the light ray via the MDD along the respective hinge axes of the MDD without overfilling the entrance pupil with the light bundle. 
     
     
       34. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to a first of the respective hinge axes and at a substantially faster second f/number parallel to the first hinge axis, wherein 
 the anamorphic optical device includes an anamorphic light tunnel having an input aperture and an output aperture, and the input aperture is larger than the output aperture. 
 
     
     
       35. The apparatus of claim 34 in which the anamorphic optical device further includes a field lens, the light rays from the anamorphic light tunnel enter the field lens. 
     
     
       36. The apparatus of claim 34 in which the input aperture is defined by an input width and an input height, and the output aperture is defined by an output width and an output height, the input width being configured to be greater than the output width. 
     
     
       37. The apparatus of claim 34 in which the anamorphic optical device increases an illumination angle of the light rays exiting the output aperture of the anamorphic light tunnel along the respective hinge axes of the MDD more than an illumination angle of the light rays entering the input aperture of the anamorphic light tunnel along the respective hinge axes. 
     
     
       38. The apparatus of claim 37 in which the anamorphic optical device increases an illumination angle of the light rays so that an entrance pupil of the projection lens accepts the illumination angle of the light ray via the MDD along the respective hinge axes of the MDD without overfilling the entrance pupil with the light bundle. 
     
     
       39. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to a first of the respective hinge axes and at a substantially faster second f/number parallel to the first hinge axis, wherein 
 the anamorphic optical device includes: 
 an anamorphic light tunnel having an input aperture and an output aperture and 
 a field lens, the light rays from the anamorphic light tunnel enter the field lens. 
 
     
     
       40. The apparatus of claim 39 in which the input aperture is defined by an input width and an input height, and the output aperture is defined by an output width and an output height, the input width being configured to be greater than the output width. 
     
     
       41. The apparatus of claim 39 in which the anamorphic optical device increases an illumination angle of the light rays exiting the output aperture of the anamorphic light tunnel along the respective hinge axes of the MDD more than an illumination angle of the light rays entering the input aperture of the anamorphic light tunnel along the respective hinge axes. 
     
     
       42. The apparatus of claim 41 in which the anamorphic optical device increases an illumination angle of the light rays so that an entrance pupil of the projection lens accepts the illumination angle of the light ray via the MDD along the respective hinge axes of the MDD without overfilling the entrance pupil with the light bundle. 
     
     
       43. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to a first of the respective hinge axes and at a substantially faster second f/number parallel to the first hinge axis, wherein 
 the anamorphic optical device includes an anamorphic light tunnel having an input aperture and an output aperture, wherein the input aperture is defined by an input width and an input height, and the output aperture is defined by an output width and an output height, the input width being configured to be greater than the output width. 
 
     
     
       44. The apparatus of claim 43 in which the anamorphic optical device increases an illumination angle of the light rays exiting the output aperture of the anamorphic light tunnel along the respective hinge axes of the MDD more than an illumination angle of the light rays entering the input aperture of the anamorphic light tunnel along the respective hinge axes. 
     
     
       45. The apparatus of claim 44 in which the anamorphic optical device increases an illumination angle of the light rays so that an entrance pupil of the projection lens accepts the illumination angle of the light ray via the MDD along the respective hinge axes of the MDD without overfilling the entrance pupil with the light bundle. 
     
     
       46. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to a first of the respective hinge axes and at a substantially faster second f/number parallel to the first hinge axis, wherein 
 the anamorphic optical device increases an illumination angle of the light rays exiting the output aperture of the anamorphic light tunnel along the respective hinge axes of the MDD more than an illumination angle of the light rays entering the input aperture of the anamorphic light tunnel along the respective hinge axes. 
 
     
     
       47. The apparatus of claim 46 in which the anamorphic optical device increases an illumination angle of the light rays so that an entrance pupil of the projection lens accepts the illumination angle of the light ray via the MDD along the respective hinge axes of the MDD without overfilling the entrance pupil with the light bundle. 
     
     
       48. In a multimedia projector in which a micro-electromechanical display device (“MDD”) includes an array of micromirrors that each pivot on a respective hinge axis to effect pixel on- and off-states whereby the MDD provides a projected image by receiving an incident illumination bundle and for pixels in the on-state reflects a reflected image bundle through a projection lens, an apparatus for increasing a brightness of the projected image comprising:
 an illumination source propagating light rays along an optical axis; 
 an anamorphic optical device receiving the light rays and forming an anamorphic incident illumination bundle that illuminates the MDD at a first f/number perpendicular to the respective hinge axes and at a substantially faster second f/number parallel to the respective hinge axes, wherein 
 the anamorphic optical device includes an anamorphic light tunnel having an input aperture and an output aperture, the input and output apertures oriented in a first direction perpendicular to the respective hinge axes, and in a second direction parallel to the respective hinge axes, the input and output apertures being configured such that when the anamorphic light tunnel is viewed along the first direction, a profile shape of the anamorphic tunnel narrows from the input aperture to the output aperture. 
 
     
     
       49. The apparatus of claim 48 wherein the input and output apertures are configured such that when the anamorphic light tunnel is viewed along the second direction, a profile shape of the anamorphic tunnel narrows less from the input aperture to the output aperture than when the anamorphic tunnel is viewed from the first direction. 
     
     
       50. The apparatus of claim 48 wherein the input and output apertures are configured such that when the anamorphic light tunnel is viewed along the second direction, a profile shape of the anamorphic tunnel does not narrow from the input aperture to the output aperture.