Color recapture using polarization recovery in a color-field sequential display system

Patent metadata

Field	Value
Publication number	US-10230928-B2
Application number	US-201514921438-A
Country	US
Kind code	B2
Filing date	Oct 23, 2015
Priority date	Oct 27, 2014
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

An image may be formed in a projection system by forming a light beam with substantially a first polarization. The light beam is directed onto a first color wheel that transmits a first selected color portion of the light beam and reflects a second color portion of the light beam. The reflected second color portion is converted to a second polarization. A first portion of the image is produced with a first spatial light modulator using the first selected color portion of the light beam having the first polarization. A second portion of the image is produced with a second spatial light modulator using at least a portion of the reflected second color portion of the light beam having the second polarization. The first portion of the image and the second portion of the image are combined to form a combined image for projection.

First claim

What is claimed is:

1. A method of producing an image, the method comprising:
forming a light beam;
directing the light beam through a polarization rotator onto a rotating color wheel having at least first, second, third and fourth segments that reflect a portion of the light beam back through the polarization rotator and that transmit a portion of the light beam through the rotating color wheel, wherein the transmitted portion has: a first color when the light beam is directed onto the first segment; a second color when the light beam is directed onto the second segment; a third color when the light beam is directed onto the third segment; and a fourth color when the light beam is directed onto the fourth segment; wherein the first, second and third colors are different primary colors from among red, green and blue; and wherein the fourth color is a secondary color from among cyan, magenta and yellow;
converting a polarization of the transmitted portion and/or the reflected portion from the first, second, third and fourth segments, so: the transmitted portion has a first polarization; and the reflected portion has a second polarization that is opposite the first polarization;
conducting the transmitted portion having the first polarization through a first optical path to a first spatial light modulator, and producing a first portion of the image with the first spatial light modulator;
conducting at least some of the reflected portion having the second polarization through a second optical path to a second spatial light modulator, and producing a second portion of the image with the second spatial light modulator, wherein the second optical path is separate and distinct from the first optical path; and
combining the first portion of the image and the second portion of the image to form a combined image for projection.

2. The method of claim 1 , wherein the color wheel is a first color wheel, the method further comprising:
directing the reflected portion onto a second color wheel that transmits only a particular color portion of the reflected portion;
wherein producing the second portion of the image with the second spatial light modulator uses the particular color portion.

3. The method of claim 1 , further comprising:
directing the reflected portion onto a particular segment of the color wheel that transmits only a particular color portion of the reflected portion;
wherein producing the second portion of the image with the second spatial light modulator uses the particular color portion.

4. The method of claim 1 , wherein combining the first portion of the image and the second portion of the image includes:
directing the first portion of the image to a first face of a polarizing beam splitter (PBS) cube, and directing the second portion of the image to a second face of the PBS cube, such that the combined image emerges from a third face of the PBS cube.

5. The method of claim 1 , wherein the color wheel is a first color wheel, the method further comprising:
filtering the reflected portion by directing the reflected portion onto a second color wheel that transmits only a particular color portion of the reflected portion;
wherein producing the second portion of the image with the second spatial light modulator uses the particular color portion.

6. The method of claim 1 , wherein the color wheel is tilted with respect to an axis of the light beam, such that the reflected portion is directed towards the second optical path.

7. The method of claim 1 , wherein an axis of the color wheel is oriented approximately parallel to an axis of the light beam, such that the reflected portion is directed along the axis of the light beam, the method further comprising:
passing the light beam through a beam splitter, and deflecting the reflected portion by the beam splitter towards the second optical path.

8. The method of claim 1 , wherein combining the first portion of the image and the second portion of the image includes:
combining the first portion of the image and the second portion of the image to form the combined image having a higher resolution than the first portion of the image by offsetting the second portion of the image with respect to the first portion of the image.

9. The method of claim 1 , wherein forming the light beam includes: forming the light beam using a laser source combined with a phosphor wheel.

10. The method of claim 1 , wherein the first spatial light modulator and the second spatial light modulator are digital micromirror devices.

11. The method of claim 1 , wherein the polarization rotator is a quarter-wave plate.

12. A projector device comprising:
image processing logic coupled to control: a first spatial light modulator (SLM) to produce a first portion of an image; and a second SLM to produce a second portion of the image;
a light source to produce a light beam;
a first polarization rotator;
a rotating color wheel;
a lens arranged to direct the light beam through the first polarization rotator onto the rotating color wheel, the rotating color wheel having at least first, second, third and fourth segments to reflect a portion of the light beam back through the first polarization rotator and to transmit a portion of the light beam through the rotating color wheel, wherein the transmitted portion has: a first color when the light beam is directed onto the first segment; a second color when the light beam is directed onto the second segment; a third color when the light beam is directed onto the third segment; and a fourth color when the light beam is directed onto the fourth segment; wherein the first, second and third colors are different primary colors from among red, green and blue; and wherein the fourth color is a secondary color from among cyan, magenta and yellow;
a second polarization rotator arranged to convert a polarization of the transmitted portion and/or the reflected portion from the first, second, third and fourth segments, so: the transmitted portion has a first polarization; and the reflected portion has a second polarization that is opposite the first polarization;
a first optical path arranged to conduct the transmitted portion having the first polarization to the first SLM;
a second optical path arranged to conduct at least some of the reflected portion having the second polarization to the second SLM, wherein the second optical path is separate and distinct from the first optical path; and
projection optics, coupled to the first SLM and to the second SLM, arranged to combine the first portion of the image produced by the first SLM with the second portion of the image produced by the second SLM into a combined image for projection.

13. The device of claim 12 , wherein the color wheel is a first color wheel, the device further comprising: a second color wheel arranged to receive the reflected portion and to transmit only a particular color portion of the reflected portion, and wherein the second SLM is arranged to produce the second portion of the image using the particular color portion.

14. The device of claim 12 , wherein a particular segment of the color wheel is arranged to receive the reflected portion and to transmit only a particular color portion of the reflected portion, and wherein the second SLM is arranged to produce the second portion of the image using the particular color portion.

15. The device of claim 12 , wherein the projection optics include a polarizing beam splitter (PBS) cube coupled to receive the first portion of the image on a first face of the PBS cube and coupled to receive the second portion of the image on a second face of the P

Assignees

• Texas Instruments Inc

Inventors

• Lyubarsky Alexander
• Pettitt Gregory Scott

Classifications

• G02B26/008

  in the form of devices for effecting sequential colour changes, e.g. colour wheels · CPC title

• H04N9/3167 Primary

  for polarizing the light beam (polarizing optical systems per se G02B27/28) · CPC title

• H04N9/3111

  for displaying the colours sequentially, e.g. by using sequentially activated light sources (sequential projection in colour photography G03B33/08) · CPC title

• G03B33/08

  Sequential recording or projection (G03B33/02, G03B33/04, G03B33/06 take precedence) · CPC title

• H04N9/3114

  by using a sequential colour filter producing one colour at a time · CPC title