Color rendering of illumination light in display systems

• US 20050024733A1
• Filed: 07/26/2004
• Published: 02/03/2005
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Richards, Peter, Combes, Michel, Huibers, Andrew
• Granted Patent: US 7,131,762 B2
• Time in Patent Office: Days
• US Class Current: 359/634
• CPC Class Codes: G01J 2003/1213 Filters in general, e.g. dichroic, band
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels

Abstract

A method and apparatus for compensating for deficiency in the illumination light from a light source is provided, where the spectrum in the visible range of light from the light source is determined, and a deficiency at a wavelength or band of wavelengths in the visible range of light is determined therefrom, a color sequencing device is provided having a set of filters comprising red, green and blue filter segments, and an additional color balancing filter segment, and wherein a the color balancing segment is constructed so as to preferentially pass a band or bands of wavelengths, which band or bands are determined based on the determined deficiency of the light source.

Claims

1. An illumination system for use in a projection system, comprising:

a light source producing light;

a set of primary color filters producing a red, green, and blue color, each having a chromaticity coordinate in a chromaticity diagram; and

a color rendering filter having a color whose chromaticity lies within a triangle zone in the chromaticity diagram, the triangle zone having a set of comer points defined by the chromaticity coordinates of the red, green, and blue primary colors but outside a white zone having comers with chromaticity coordinates of (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375).

2. The system of claim 1, wherein the red color lies within a zone defined by a set of comer points with coordinates of (0.48, 0.42), (0.568, 0.265), (0.735, 0.265), (0.545, 0.45), and (0.48, 0.42);

wherein the green color lies within a zone defined by a set of comer points with coordinates (0.026, 0.399), (0.166, 0.364), (0.379, 0.494), (0.389, 0.607), (0.273, 0.719), and (0.026, 0.399); and

wherein the blue color lies within a zone defined by a set of corner points with coordinates (0.078, 0.171), (0.15, 0.22), (0.25, 0.146), (0.169, 0.002), (0.12, 0.058), and (0.078, 0.171).

3. The system of claim 1, wherein the primary red, green, and blue colors have the chromaticity coordinates of (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325), respectively.

4. The system of claim 1, wherein the light source is an arc lamp.

5. The system of claim 1, further comprising a color wheel having the set of primary color filters and the color rendering filter.

6. The system of claim 1, wherein the primary colors comprise yellow, cyan, and magenta.

7. The system of claim 1, further comprising:

a light pipe.

8. The system of claim 7, wherein the light pipe is positioned between the light source and the color wheel.

9. The system of claim 7, wherein the light pipe is positioned after the light pipe at the propagation path of the light from the light source.

10. The system of claim 1, wherein the primary color segments are operable to produce a first white color within the white zone;

and the primary color segments and the color rendering segment in together are operable to produce a second white color within the white zone;

wherein the first and second white colors are spaced as far away as the white allowing.

11. The system of claim 1, wherein the color of the color rendering segment lies within a triangle zone YNO in the CIE chromaticity chart, wherein N is a color of the light from the light source;

wherein Y is a color produced by the light from the light source passing through 100% and 80% of the green and red filter, respectively; and

wherein O is the color produced by the light from the light source passing through the 90% of the green segment and 100% of the red segment.

12. The system of claim 11, wherein point N has coordinates of (0.296, 0.322) in the CIE chromaticity chart.

13. The system of claim 1, wherein the color of the color rendering segment lies within a triangle zone of NCA in the CIE chart, wherein N is a color of the light from the light source;

wherein C is a color produced by the color from the light source passing 100%, 60%, and 0% of the green, blue, and red segment, respectively; and

wherein A is a color produced by passing the light from the light source through 92% of the green segment and 100% of the blue segment.

14. The system of claim 13, wherein point N has coordinates of (0.296, 0.322) in the CIE chromaticity chart.

15. The system of claim 1, wherein the color of the color rendering segment lies within a hexagon zone G₂Y₂R₂M₂B₂C₂ in the chromaticity diagram, wherein G₂ is the color produced by the white light from the light source shining through 100% of the green segment, 25% of the Red segment, and 25% of the Blue segment;

wherein Y₂ is the color produced by the white light from the light source shining through 100%, 25% and 25% of the Green, the Red, and the Blue segment, respectively;

wherein R₂ is the color produced by the white light from the light source shining through 25%, 100%, and 25% of the Green, the Red, and the Blue segment, respectively;

wherein M₂ is the color produced by the white light from the light source shining through 25%, 100%, and 100% of the Green, the Red, and the Blue segment, respectively;

wherein B₂ is the color produced by the white light from the light source shining through 25%, 25%, and 100% of the Green, the Red, and the Blue segment, respectively; and

wherein C₂ is the color produced by the white light from the light source shining through 100%, 25%, and 100% of the Green, the Red, and the Blue segment, respectively.

16. An illumination system for use in a projection system, comprising:

a light source producing light;

a set of primary color filters producing red, green, and blue illumination; and

a color rendering filter having a color that lies within a sector between a line NC₁ and a line NC₂ in a chromaticity diagram but outside a white zone having comers with chromaticity coordinates of (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375), and with exclusion of the colors belonging to a zone having comers of (0.368, 0.539), (0.421, 0.486), (0.460, 0.540); and

(0.387, 0.610), wherein N is the color of light from the light source; and

C₁ corresponds to a color of light from a light source with a wavelength proximate to 610 nanometers, while C₂ corresponds to a color of light from a light source with a wavelength proximate to 546 nanometers.

17. The system of claim 16, wherein the C₁ and C₂ have coordinates in the chromaticity diagram of (0.666, 0.334) and (0.237, 0.718), respectively.

18. The system of claim 16, wherein the color of the color rendering filter has the chromaticity coordinates in the CIE chart of (x, y);

and wherein x, y satisfy;

y>

0.0313·

x+0.313 AND y<

−

17.096·

x+5.384

19. The system of claim 16, wherein point N has the coordinates of (0.296, 0.322) in the CIE chromaticity chart.

20. The system of claim 16, wherein the color rendering segment has a color that lies within a zone with the corners having the coordinates of (0.565, 0.346), (0.735, 0.265), (0.648, 0.351), and (0.421, 0.486).

21. The system of claim 16, wherein the color rendering segment has a color that lies within a zone with the corners having the coordinates of (0.286, 0.446), (0.207, 0.771), (0.368, 0.539), and (0.387, 0.610).

22. The system of claim 16, wherein the color rendering segment has a color that lies within a zone with the comers having the coordinates of (0.210, 0.16), (0.15, 0.22), (0.166, 0.364), and (0.286, 0.446).

23. An illumination system for use in a projection system, comprising:

a light source producing light;

a set of primary color filters producing red, green, and blue illumination; and

a color rendering filter having a color that lies within a sector between a line NA₁ and a line NA₂ in a chromaticity chart but outside a white zone having corners with coordinates (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375), and with exclusion of a zone having corners with chromaticity of (0.15, 0.22), (0.21, 0.16), (0.286, 0.446), (0.166, 0.364), and (0.15, 0.22), wherein N is the color of light from the light source; and

A₁ corresponds to a color of light from a light source with a wavelength proximate to 560 nanometers, while A₂ corresponds to a color of light from a light source with a wavelength proximate to 430 nanometers.

24. The system of claim 23, wherein A₁ and A₂ have chromaticity coordinates of (0.373, 0.624) and (0.169, 0.007), respectively.

25. The system of claim 23, wherein point N has the coordinates of (0.296, 0.322) in the CIE chromaticity chart.

26. The system of claim 23, wherein the color of the color rendering filter has the chromaticity coordinates in the CIE chart of (x, y);

and wherein x, y satisfy;

y>

3.922·

x−

0.839 AND y>

2.48·

x−

0.412

27. The system of claim 23, wherein the color of the color rendering segment has a chromaticity coordinates that are not within a zone having corner points with chromaticity coordinates of (0.565, 0.346), (0.735, 0.265), (0.648, 0.351), and (0.421, 0.486).

28. The system of claim 23, wherein the color of the color rendering segment has a chromaticity coordinates that are not within a zone having comer points with chromaticity coordinates of (0.286, 0.446), (0.207, 0.771), (0.368, 0.539), and (0.387, 0.610).

29. An illumination system for use in a projection system, comprising:

a light source producing light;

a set of primary color filters producing a number of N primary colors; and

a color rendering filter having a non-primary color that is different from the N primary colors, wherein said non-primary color is not white.

30. The system of claim 29, wherein the primary colors comprise red, green, and blue.

31. The system of claim 29, wherein the primary colors comprise yellow, cyan, and magenta.

32. The system of claim 29, wherein the white is a color within a white zone with the corner points having coordinates in the CIE chart of (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375).

33. An illumination system for use in a display system, comprising:

a light source producing light;

a color wheel, further comprising;

a set of primary color segments producing primary colors of red, green, and blue; and

a color rendering segment, wherein the color rendering segment has a color that is determined based upon a product function that is proportional to a product of the luminance sensitivity of a viewer'"'"'s eyes, a spectrum of the light from the light source and a predetermined wavelength threshold of the product function.

34. The system of claim 33, wherein the predetermined wavelength threshold has such a value that a resulted color from the illumination system is outside a white zone in the CIE chart, wherein the white zone has comers with coordinates of (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375).

35. The system of claim 33, wherein the threshold has a value of 0.0017.

36. A method of modulating light from a light source in a display system that has a color wheel and a spatial light modulator having an array of pixels, the method comprising:

dividing a frame of time into a set of primary time slots and at least one color rendering time slot;

illuminating the pixels with a set of sequential primary colors and a rendering color;

loading a set of image data for the primary colors into the pixels during the primary time slots; and

loading a set of color rendering data into the pixels during the color rendering time slot, wherein the color rendering data are derived from the image data having the maximum value.

37. A method of rendering a sequence of primary color beams shining on an array of pixels of a spatial light modulator of a display system, comprising:

determining a first white color produced by the sequence of primary colors; and

adding an additional color component into the sequence of primary color beams, wherein the additional color component has a color such that the first white color is spaced as far away from a second white color within a white zone in the CIE 1931 chromaticity chart,

wherein white zone is defined by US DMV; and

wherein the second white color is a color produced by the primary colors and the additional color component.

38. The method of claim 37, further comprising:

determining the additional color by;

a) determining the first white color, the second white color, a neutral color, and a neutral-primary color in the CIE chart; and

b) determining an intersection of a first line and a second line, wherein the first line connecting the first and second white color; and

wherein the second line passing through the neutral color and parallel to a line connecting the second white and the neutral-primary color; and

c) defining the color of such determined intersection as the additional color.

39. The method of claim 37, wherein the light source has a high temperature white.

40. The method of claim 37, wherein the light source has a low temperature white.