Etendue reduced stereo projection using segmented disk
View Patent ↗A stereoscopic digital image projecting system has a light source system energizable to provide polarized illumination having a first polarization state and a beam splitting system alternately generating first and second light beams having different polarization states from the polarized illumination. A combining system has a polarization beam combiner that combines the first and second light beams into a combined light beam. A spatial light modulator is used to modulate the combined light beam in a manner consistent with stereoscopic image data to form a first modulated image from illumination in the combined light beam having the first polarization state and to form a second modulated image from illumination in the combined light beam having the second polarization state. Projection optics are configured to project the first and second modulated images onto a display surface.
1. A stereoscopic digital image projecting system for projecting stereoscopic image data including left-eye image data and right-eye image data, comprising:
a light source system energizable to provide polarized illumination having a first polarization state;
a beam splitting system that alternately generates first and second light beams from the polarized illumination, the first light beam having a first polarization state and being directed along a first optical path and the second light beam having a second polarization state and being directed along a second optical path, wherein when the beam splitting system is generating the first light beam substantially no light is directed along the second optical path, and when the beam splitting system is generating the second light beam substantially no light is directed along the first optical path;
a combining system comprising a polarization beam combiner that combines the first and second light beams into a combined light beam directed along a common optical path, wherein the combined light beam alternates between the first and second polarization states;
a spatial light modulator modulating the combined light beam in a manner consistent with the stereoscopic image data, wherein the spatial light modulator alternately forms first and second modulated images, the first modulated image being formed by modulating the combined light beam using the left eye image data when the combined light beam is in the first polarization state and the second modulated image being formed by modulating the combined light beam using the right eye image data when the combined light beam is in the second polarization state; and
projection optics configured to project the first and second modulated images.
2. The system of claim 1 , wherein the polarization beam combiner transmits the first light beam and reflects the second light beam.
3. The system of claim 1 , wherein the polarization beam combiner is a thin film plate, thin film cube, wire grid, or Brewster angle element.
4. The system of claim 1 , wherein the combined light beam has alternating polarization states from the first and second light beams, and wherein spatial and angular characteristics of the combined light beam are equivalent or substantially equivalent between the alternating polarization states.
5. The system of claim 4 , wherein the thickness, angle of incidence, and refractive index of components in the optical paths of the first and second light beams are configured to cause the equivalence or substantial equivalence of the spatial and angular characteristics of the first and second light beams.
6. The system of claim 1 , wherein the beam splitting system comprises polarization beam splitters configured to direct the first and second light beams into the polarization beam combiner.
7. The system of claim 6 , wherein the polarization beam splitters are thin film plates, thin film cubes, wire grids, or Brewster angle elements.
8. The system of claim 7 , wherein the polarization beam splitters and the polarization beam combiner are thin film plates.
9. The system of claim 1 , wherein the beam splitting system comprises a polarization rotator in a path of the first light beam.
10. The system of claim 9 , wherein the polarization rotator is a half-wave plate or an electronic retarder.
11. The system of claim 9 , wherein the first light beam and the second light beam have orthogonal polarization states.
12. The system of claim 11 , wherein the orthogonal polarization states are opposing circular polarization states.
13. The system of claim 9 , wherein the first light beam and the second light beam have non-orthogonal polarization states.
14. The system of claim 13 , wherein the polarization rotator is positioned to produce a match or substantial match in light output intensity of the first and second light beams upon output from the polarization beam combiner.
15. The system of claim 1 , further comprising a uniformizing system configured to uniformize the polarized illumination, wherein the beam splitting system generates the first and second light beams from the uniformized polarized illumination.
16. The system of claim 15 , wherein the uniformizing system comprises an integrating bar or a lenslet array.
17. The system of claim 1 , further comprising a uniformizing system configured to uniformize the combined light beam, wherein the spatial light modulator modulates the uniformized combined light beam.
18. The system of claim 17 , wherein the uniformizing system comprises an integrating bar or a lenslet array.
19. The system of claim 13 , wherein the polarization rotator is positioned to produce a non-orthogonal relationship of the first and second light beams upon output from the polarization beam combiner.
20. The system of claim 1 , wherein the spatial light modulator is a micro-mirror device.