Three dimensional image projector with circular light polarization

• US 8,992,024 B2
• Filed: 01/25/2012
• Issued: 03/31/2015
• Est. Priority Date: 01/25/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: DeCusatis, Casimer M.
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US13/357,767
• Publication Number:
  US 20130188150A1
• Time in Patent Office: 1,161 Days
• Field of Search: 353/8, 353/81, 353/20, 353/98, 348/57, 359/583, 359/629, 359/634, 359/251
• US Class Current: 353/20
• CPC Class Codes: G02B 5/12 Reflex reflectors
• CPC Class Codes: G02B 6/27 with polarisation selective and adjusting means
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: G03B 35/26 using polarised or coloured light separating different viewpoint images

Abstract

A system is provided for projecting a three-dimensional image. The system includes a light source and a polarization conversion system for converting light emitted from the light source to circular polarization. A beam splitter device is disposed adjacent the light source to receive light, and an LCoS image device is disposed adjacent the beam splitter device.

Claims

1. A light source comprising:

a conic section reflector;

a light emitting diode (LED) mounted on the conic section reflector; and

,

a polarization conversion system (PCS) adjacent the LED, the PCS comprising a linear polarizer having an axis of polarization and a rotatable wave plate;

wherein the rotatable wave plate rotates about an optic axis of the LED between a first position and a second position, the first position and the second position being 90 degrees apart.

2. The light source according to claim 1 wherein the rotatable wave plate is in the first position when the rotatable wave plate forms a 45 degree angle with the linear polarizer'"'"'s axis of polarization.

3. The light source according to claim 1 wherein the rotatable wave plate is in the second position when the rotatable wave plate forms a negative 45 degree angle with the linear polarizer'"'"'s axis of polarization.

4. The projector of claim 1 wherein the LED is configured to periodically emit light, and the wave plate is configured to be oriented in one of the first position and the second position when the light is emitted.

5. The projector of claim 4 wherein the wave plate is configured to sequentially create alternating light having left-handed circular polarization and right-handed circular polarization when light is emitted by the LED.

6. A projector comprising:

a light source comprising a plurality of LEDs;

a polarization conversion system (PCS) adjacent each of the plurality of LEDs, each PCS comprising a linear polarizer having an axis of polarization and a rotatable wave plate, wherein the rotatable wave plate rotates about an optic axis of an LED between a first position and a second position, the first position and the second position being 90 degrees apart;

a polarizing beam splitter (PBS) adjacent the light source; and

,

an imaging device adjacent the PBS.

7. The projector system of claim 6 further comprising a projection lens assembly adjacent the PBS opposite the imaging device.

8. The projector of claim 7 wherein the plurality of LEDs are configured to periodically emit light, and each wave plate is configured to be oriented in one of the first position and the second position when the light is emitted.

9. The projector of claim 8 wherein each wave plate is configured to sequentially create alternating light having left-handed circular polarization and right-handed circular polarization when light is emitted by the LED.

10. The projector system of claim 6 wherein the light source comprises a plurality of conic section reflectors such that each of the plurality of LEDs is mounted on a conic section reflector.

11. The projector system of claim 6 wherein the rotatable wave plate is in the first position when the wave plate forms a 45 degree angle with the linear polarizer'"'"'s axis of polarization.

12. The projector system of claim 6 wherein the rotatable wave plate is in the second position when the wave plate forms a negative 45 degree angle with the linear polarizer'"'"'s axis of polarization.

13. The projector of claim 6 further comprising:

a fly'"'"'s eye lens arranged between the light source and the PBS; and

,

a pre-polarizer lens arranged between the fly'"'"'s eye lens and the PBS.

14. The projector of claim 13 further comprising:

a plurality of light collection optics, each of the plurality of light collection optics associated with one of the plurality of LEDs; and

,

a dichroic color combiner disposed between the plurality of light collection optics, the dichroic color combiner arranged to direct light from the plurality of LEDs into the fly'"'"'s eye lens.

15. The projector according to claim 6, wherein the imaging device is an LCoS device.