Light-emitting diode (LED) illumination in display systems using spatial light modulators (SLM)

• US 20070013871A1
• Filed: 07/15/2005
• Published: 01/18/2007
• Est. Priority Date: 07/15/2005
• Status: Abandoned Application

• Current Assignee: Stephen Marshall, Steven Penn
• Original Assignee: Stephen Marshall, Steven Penn
• Inventors: Penn, Steven, Marshall, Stephen
• Application Number:
  US11/182,246
• Publication Number:
  US 20070013871A1
• Time in Patent Office: Days
• US Class Current: 353/20
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: H04N 9/312 Driving therefor driving of electronic spatial light modulators in displays other than projection devices G09G3/34, G09G3/36; control of liquid crystal elements G02F1/133; control of micromechanical modulators G02B26/08
• 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

Abstract

System and method for enhancing performance in an SLM display system using LED illumination. A preferred embodiment comprises computing a set of spectral characteristics, analyzing the set of spectral characteristics, and modulating a light produced by a light source of a display system based upon the analysis, wherein the light source comprises one or more light-emitting diodes. The spectral characteristics can provide information regarding either the images being displayed by the display system or an operating environment of the display system. Either can have an impact upon the quality of the images being displayed on the display system and can be used to make adjustments to the light source.

Claims

1. A method for operating a display system, the method comprising:

computing a set of spectral characteristics;

analyzing the set of spectral characteristics; and

modulating a light produced by a light source of the display system based upon the analysis, wherein the light source is capable of rapidly switching and is modulatable.

2. The method of claim 1, wherein the spectral characteristics are computed from images as they are being displayed by the display system.

3. The method of claim 2, wherein the spectral characteristics are computed prior to an image being displayed by the display system.

4. The method of claim 1, wherein the spectral characteristics are computed from a sampling of an operating environment of the display system.

5. The method of claim 4, wherein an optical sensor provides samples of the operating environment.

6. The method of claim 1, wherein the analysis determines that more than a specified number of pixels have an intensity of less than a specified threshold, and wherein the modulating comprises turning off the light source for a period of time substantially equal to a display time required to display pixels exceeding the specified threshold.

7. The method of claim 6, wherein pixels having an intensity of greater than the specified threshold are displayed with an intensity substantially equal to the specified threshold.

8. The method of claim 6, wherein the modulating comprises turning off the light source for a period of time less than the display time and turning the light source off for the display of pixels with very low intensities, wherein a sum of the time that the light source is off is substantially equal to the display time required to display pixels exceeding the specified threshold.

9. The method of claim 1, wherein each pixel in an image comprises a plurality of color components, wherein the analysis analyzes each color component of each image, and wherein the modulating comprises modulating each color component of the light.

10. The method of claim 9, wherein the modulating comprises adjusting a hue of a color component.

11. The method of claim 1 further comprising prior to the modulating, determining an operating mode of the display system.

12. The method of claim 11, wherein the modulating comprises reducing an intensity of the light in response to a determination that the display system is operating on battery power.

13. The method of claim 11, wherein the modulating comprises reducing an intensity of the light in response to a determination that the display system is operating in a low power mode.

14. The method of claim 1, wherein the display system makes use of a spatial light modulator, and wherein the modulating comprises turning on the light source for a period of time that is less than a shortest amount of time that the spatial light modulator can use to represent a single state.

15. A display system comprising:

a spatial light modulator, the spatial light modulator configured to create images comprised of pixels by setting each light modulator in an array of light modulators into a state matching a corresponding pixel value;

a rapid switching and modulatable light source (RSMLS) to optically illuminate the spatial light modulator, the RSMLS capable of switching at a faster rate than a rate of state switching for light modulators in the spatial light modulator and producing a light of specifiable intensity and color.

16. The display system of claim 15 further comprising a display screen to display the images reflected from the spatial light modulator.

17. The display system of claim 15, wherein the spatial light modulator comprises an array of micromirrors.

18. The display system of claim 15, wherein the spatial light modulator comprises an array of deformable mirrors.

19. The display system of claim 15, wherein the RSMLS comprises a light-emitting diode (LED).

20. The display system of claim 19, wherein the RSMLS comprises a plurality of LEDs.

21. The display system of claim 20, wherein the RSMLS comprises different colored LEDs.

22. The display system of claim 19, wherein the LED is a phosphor coated LED.

23. The display system of claim 21, wherein the RSMLS comprises:

a first LED configured to produce a first color component of the light;

a first lens positioned between the first LED and a light output of the RSMLS, the first lens to focus light produced by the first LED;

a second LED configured to produce a second color component of the light;

a second lens positioned between the second LED and a first filter, the second lens to focus light produced by the second LED and the first filter to pass light produced by the first LED and to reflect light produced by the second LED;

a third LED configured to produce a third color component of the light; and

a third lens positioned between the third LED and a second filter, the third lens to focus light produced by the third LED and the second filter to pass light produced by the first LED and the second LED and to reflect light produced by the third LED.

24. The display system of claim 23, wherein the first filter further rejects a portion of a light spectrum of light produced by the first LED, and wherein the second filter further rejects a portion of a light spectrum of light produced by the second LED.

25. The display system of claim 15, wherein the RSMLS comprises a laser.