Polarization compensated stereoscopic systems
Disclosed embodiments include stereoscopic systems having at least one compensator operable to reduce the sensitivity of polarization control over incidence angle of image source optics and analyzer optics. In an exemplary embodiment, the disclosed compensator is operable to compensate polarization changes induced by optics at either or both the image source subsystem and the analyzer subsystem, in which the polarization changes would be operable to cause leakage at the analyzer subsystem if uncompensated. As such, the disclosed compensators and compensation techniques are operable to reduce leakage at the analyzer subsystem even if the disclosed compensator may be located at the analyzer subsystem.
1. A stereoscopic imaging system, comprising:
an image source subsystem operable to output light of first and second states of polarization (SOP);
an analyzer subsystem operable to substantially block light of the first SOP from traveling along a first path, and to substantially block light of the second SOP from traveling along a second path;
wherein the image source subsystem comprises a first optical element operable to cause a first polarization change on light passing therethrough, and the analyzer subsystem comprises a second optical element operable to cause a second polarization change on light passing therethrough, further wherein the first optical element comprises a polarizer and a quarter wave retarder, both of which optically follow an image source of the image source subsystem, further wherein the second optical element comprises a polarizer and a quarter wave retarder in the analyzer subsystem;
wherein the first and second polarization changes, if not compensated, would at least partially cause at least one of a leakage of light of the first SOP along the first path or a leakage of light of the second SOP along the second path; and
wherein the image source subsystem or the analyzer subsystem comprises a compensator configured to at least reduce both the first and second polarization changes.
2. The stereoscopic imaging system of claim 1 , wherein the image source subsystem comprises at least one projector, and the compensator is disposed in the image source subsystem optically following the at least one projector.
3. The stereoscopic imaging system of claim 1 , wherein the first and second polarization changes each comprise a geometric rotation, and the compensator comprises a biaxially stretched retarder operable to substantially correct the geometric rotation.
4. The stereoscopic imaging system of claim 1 , wherein the first and second polarization changes each comprise a geometric rotation, and the compensator comprises a +A-plate and a +C-plate operable to cooperate to substantially correct a combined geometric rotation of the first and second polarization changes.
5. The stereoscopic imaging system of claim 1 , wherein the first and second polarization changes each comprise a −C-plate type retardation, and the compensator comprises at least one +C-plate operable to substantially correct a combined −C-plate type retardation of the first and second polarization changes.
6. The stereoscopic imaging system of claim 1 , wherein the compensator is optimized for performance measurements for an ideal viewer centered horizontally with respect to screen center.
7. The stereoscopic imaging system of claim 6 , wherein the compensator is optimized for baseline acceptable performance measurements for viewers in extreme locations of a viewing space with respect to the location of the ideal viewer.
8. The stereoscopic imaging system of claim 6 , wherein the compensator is optimized for maximizing performance measurements for as large a population surrounding the ideal viewer as possible.
9. The stereoscopic imaging system of claim 1 , wherein the image source subsystem comprises a sequentially or spatially modulated LCD panel operable to output light of the first and second states of polarization.
10. A stereoscopic projector system, comprising:
a projection subsystem operable to output light of first and second states of polarization (SOP);
an analyzer subsystem operable to substantially block light of the first SOP from traveling along a first path and to substantially block light of the second SOP from traveling along a second path;
wherein the projector subsystem comprises a first optical element operable to cause a first polarization change on light passing therethrough, and the analyzer subsystem comprises a second optical element operable to cause a second polarization change on light passing therethrough,
wherein the first and second polarization changes, if not compensated, would at least partially cause at least one of a leakage of light of the first SOP along the first path or a leakage of light of the second SOP along the second path; and
wherein the projector subsystem comprises a compensator configured to at least reduce both the first and second polarization changes.
11. The stereoscopic projection system of claim 10 , wherein:
the projection subsystem comprises:
left and right projectors,
a second compensator, and
a third optical element operable to cause a third polarization change on light passing therethrough; and
the analyzer subsystem comprises a fourth optical element operable to cause a fourth polarization change on light passing therethrough;
wherein the first and third optical elements optically follow the left and right projectors, respectively, wherein the compensator and second compensator optically follow the left and right projectors, respectively;
wherein the first and second polarization changes, if not compensated, would at least partially cause the leakage of light of the first SOP along the first path, and the third and fourth polarization changes, if not compensated, would at least partially cause the leakage of light of the second SOP along the second path, and
wherein the second compensator is configured to at least reduce both the third and fourth polarization changes.
12. The stereoscopic projection system of claim 10 , wherein a vertical offset between a projector of the projection subsystem and a viewer at least partially contributes to the first and second polarization changes, and the compensator is operable to at least partially correct the first and second polarization changes due to the vertical offset.
13. The stereoscopic projection system of claim 10 , wherein the compensator comprises an O-plate.
14. The stereoscopic projection system of claim 10 , wherein a difference between an incidence angle of a projector of the projection subsystem and an incidence angle of a viewer at least partially contributes to the first and second polarization changes, and the compensator is operable to at least correct the first and second polarization changes due to the difference.
15. A stereoscopic display system, comprising:
an image source subsystem operable to output light of first and second states of polarization (SOP), the image source subsystem comprising:
an LCD panel:
an exit polarizer optically following the LCD panel, and
a stripe patterned quarter wave plate (QWP) aligned with the LCD panel; and
an analyzer subsystem operable to substantially block light of the first SOP from traveling along a first path, and to substantially block light of the second SOP from traveling along a second path, the analyzer subsystem comprising analyzing quarter wave plates and polarizers each being operable to receive light from one of the analyzing quarter wave plates;
wherein a first +C-plate is either disposed in the image source subsystem between the exit polarizer and the stripe patterned QWP, or disposed in the analyzer subsystem optically following one of the analyzing quarter wave plates.
16. The stereoscopic display system of claim 15 , further comprising a second +C-plate, wherein both the first and second +C-plate are disposed in the analyzer subsystem optically following the respective analyzing quarter wave plates, wherein the first and second +C-plate are operable to each compensate for a −C-plate type retardation caused by the respective analyzing quarter wave plates and the stripe patterned quarter wave plate.
17. The stereoscopic display system of claim 15 , wherein the first +C-plate is disposed in the image source subsystem and is operable to substantially compensate for a −C-plate type retardation caused by the analyzing quarter wave plates and the stripe patterned quarter wave plate.
18. The stereoscopic display system of claim 15 , further comprising at least one compensating element operable to substantially compensate a geometric rotation and a retardation caused by the exit polarizer of the image source subsystem and the polarizers of the analyzer subsystem.