IMAGE PATH LIGHT INTENSITY SENSING IN LIGHT PROJECTOR

• US 20100328609A1
• Filed: 06/25/2009
• Published: 12/30/2010
• Est. Priority Date: 06/25/2009
• Status: Active Grant

• Current Assignee: IMAX Corporation
• Original Assignee: Eastman Kodak Company
• Inventors: Corey, Richard P., Silverstein, Barry D.
• Granted Patent: US 8,220,938 B2
• Time in Patent Office: Days
• US Class Current: 353/7
• CPC Class Codes: G03B 21/2013 Plural light sources
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/2053 Intensity control of illuminating light controlled by video signal processing H04N5/74 or H04N9/31
• CPC Class Codes: G03B 33/12 using beam-splitting or beam-combining systems, e.g. dichroic mirrors
• CPC Class Codes: G03B 35/26 using polarised or coloured light separating different viewpoint images
• CPC Class Codes: H04N 13/133 Equalising the characteristics of different image components, e.g. their average brightness or colour balance
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

In a light projection system, potentially hierarchical levels of light intensity control ensure proper laser-light output intensity, color channel intensity, white point, left/right image intensity balancing, or combinations thereof. The light projection system can include a light intensity sensor in an image path, in a light-source subsystem light-dump path, in a light-modulation subsystem light-dump path, in a position to measure light leaked from optical components, or combinations thereof.

Claims

1. A light projection system comprising:

a projection subsystem configured at least to project an image;

a light source subsystem configured at least to generate light directed along an image path leading to the projection subsystem; and

a light-intensity-measurement subsystem configured at least to determine an intensity of the light and comprising a light-intensity sensor in the image path.

2. The system of claim 1, wherein the sensor is on a shutter in a closed position that prevents further projection of the light along the image path.

3. The system of claim 1,

wherein the image forming subsystem further comprises a plurality of light source subsystems, each configured at least to generate a single color channel of a plurality of color channels of light generated by the image forming subsystem,

wherein the light-intensity measurement subsystem is further configured at least to determine an intensity of each of the plurality of color channels of light.

4. The system of claim 3, wherein each of the plurality of color channels of light have an associated image path, a portion of which is shared by all of the plurality of color channels of light, and wherein the light-intensity-measurement subsystem comprises a light-intensity sensor for each of the plurality of color channels of light in a non-shared portion of the respective image paths.

5. The system of claim 3,

wherein each of the plurality of color channels of light have an associated image path, at least a portion of which is shared by all of the plurality of color channels of light, and wherein the light-intensity-measurement subsystem comprises a light-intensity sensor in the shared portion of the image paths.

6. The system of claim 5, wherein the light-intensity-measurement subsystem is further configured at least to determine a white point of the plurality of color channels of light based on information received from the light-intensity sensor in the shared portion of the image paths.

7. The system of claim 1, wherein the light is stereoscopic light comprising a left-eye light beam and a right-eye light beam that follow a same path along the image path.

8. The system of claim 7, wherein the light-intensity sensor is configured at least to measure light intensity during a blanking period between the left-eye and right-eye light beams.

9. A method for measuring light intensity generated by a light projection system, the method comprising:

generating light from a light source subsystem, the light directed along an image path leading to a projection subsystem;

determining an intensity of the light with a light-intensity sensor in the image path.

10. The method of claim 9, wherein the sensor is on a shutter, and the method further comprises closing the shutter and preventing further projection of the light along the image path prior to performing the determining.

11. The method of claim 9,

wherein the generating generates a plurality of color channels of light, each from one of a plurality of light source subsystems, and

wherein the determining determines an intensity of each of the plurality of color channels of light.

12. The method of claim 11, wherein each of the plurality of color channels of light have an associated image path, a portion of which is shared by all of the plurality of color channels of light, and wherein the determining determines an intensity of each of the plurality of color channels of light with a light-intensity sensor in each color channel'"'"'s non-shared portion of its image path.

13. The method of claim 11, wherein each of the plurality of color channels of light have an associated image path, at least a portion of which is shared by all of the plurality of color channels of light, and wherein the determining determines an intensity of each of the plurality of color channels of light with a light-intensity sensor in the shared portion of the image paths.

14. The method of claim 13, further comprising determining a white point of the plurality of color channels of light based on information received from the light-intensity sensor in the shared portion of the image paths.

15. The method of claim 9, wherein the light is stereoscopic light comprising a left-eye light beam and a right-eye light beam that follow a same path along the image path.

16. The method of claim 15, wherein the determining determines light intensity during a blanking period between the left-eye and right-eye light beams.