Distortion matching polarization conversion systems and methods thereof

• US 20170131624A1
• Filed: 11/10/2016
• Published: 05/11/2017
• Est. Priority Date: 11/10/2015
• Status: Active Grant

• Current Assignee: RealD Incorporated
• Original Assignee: RealD Incorporated
• Inventors: Schuck, Miller H., McKnight, Douglas J.
• Granted Patent: US 10,459,321 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02F 1/0136 for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation G02F1/0353 takes precedence
• CPC Class Codes: G03B 21/142 Adjusting of projection optics
• CPC Class Codes: G03B 21/147 Optical correction of image distortions, e.g. keystone
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: G03B 2205/00 Adjustment of optical system relative to image or object surface other than for focusing
• CPC Class Codes: G03B 35/22 using single projector with stereoscopic-base-defining system

Abstract

Optical systems having at least one polarization beam splitter (PBS) are operable to receive randomly-polarized light bundles from a projector lens. The PBS is further operable to direct light bundles having a state of polarization (SOP) along a light path and operable to direct other light bundles having a different SOP along different light paths. The light paths have optical path lengths which may differ. Each light path produces an image having a distortion which may differ from the distortion of an image produced by a different light path. A compensation in a light path is operable to convert a non-compensated distortion of an image into a compensated distortion that more closely matches the distortion of images in other light paths.

Claims

1. An optical system, comprising:

at least one polarization beam splitter (PBS) operable to receive randomly-polarized light bundles from a projector lens, further operable to direct first light bundles having a first state of polarization (SOP) along a first light path having a first optical path length to produce a first image having a first non-compensated distortion, and further operable to direct second light bundles having a second SOP along a second light path having a second optical path length to produce a second image having a second distortion; and

a compensation in the first light path, the compensation operable to convert the first non-compensated distortion into a first compensated distortion, the first compensated distortion more closely matching the second distortion than the first non-compensated distortion.

2. The optical system of claim 1, wherein the first non-compensated distortion is greater than the second distortion, and wherein the compensation removes distortion from the first light path.

3. The optical system of claim 1, wherein the first non-compensated distortion is less than the second distortion, and wherein the compensation introduces additional distortion to the first light path.

4. The optical system of claim 3, wherein the second distortion is trapezoidal.

5. The optical system of claim 1 further comprising a lens pair in the first light path, wherein the compensation creates a vertical tilt in at least one of the lenses in the lens pair.

6. The optical system of claim 5, wherein the compensation creates a vertical tilt of 1.5 degrees in only one of the lenses in the lens pair.

7. The optical system of claim 1, wherein the compensation is achieved by adjusting a mounting location associated with the optical system.

8. The optical system of claim 1, wherein the compensation is achieved by a mechanical device.

9. The optical system of claim 8, wherein the mechanical device is selected from the group consisting of a shim and a hinge.

10. The optical system of claim 8, wherein the mechanical device is a 2.9 millimeter shim.

11. The optical system of claim 1, wherein the first light path is a transmitted light path, and wherein the second light path is a reflected light path.

12. The optical system of claim 1, wherein the at least one PBS is further operable to direct third light bundles having the first SOP along a third light path having a third optical path length to produce a third image having a third non-compensated distortion, the optical system further comprising:

a second compensation in the third light path, the second compensation operable to convert the third non-compensated distortion into a third compensated distortion, the third compensated distortion more closely matching the second distortion than the third non-compensated distortion.

13. The optical system of claim 12 further comprising a first half-lens pair in the first light path and a second half-lens pair in the third light path, wherein the compensation creates a vertical tilt in at least one of the half-lenses in the first half-lens pair, and wherein the second compensation creates a vertical tilt in at least one of the half-lenses in the second half-lens pair.

14. The optical system of claim 12, wherein the first optical path length is substantially similar to the third optical path length, wherein the first non-compensated distortion is substantially similar to the third non-compensated distortion, and wherein the first compensated distortion is substantially similar to the third compensated distortion.

15. The optical system of claim 1, further comprising:

a polarization rotator located on the first light path, the polarization rotator being operable to translate the first SOP to the second SOP.

16. The optical system of claim 15, further comprising:

a polarization switch operable to receive first and second light bundles from the first and second light paths respectively, and further operable to selectively translate the polarization states of the first and second light bundles to one of a first output SOP and a second output SOP, wherein the polarization switch comprises first and second polarization switch panels, the first polarization switch panel receiving light from the first light path, and the second polarization switch panel receiving light from the second light path.

17. The optical system of claim 1, wherein the first non-compensated distortion is substantially no distortion.