Color rendering of illumination light in display systems

• US 20050024734A1
• 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 7,212,359 B2
• Time in Patent Office: Days
• US Class Current: 359/634
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08

Abstract

A method and a color rendering filter for compensating for deficiency in illumination light from a light source in display systems are provided. The color rendering filter has a color that is determined based upon the spectrum, sensitivity of viewer'"'"'s eyes over the visible light range, and a pre-determined waveband threshold.

Claims

1. 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.

2. The system of claim 1, wherein the color rendering filter has a color whose chromaticity lies within a triangle zone in the CIE 1931 chromaticity chart, the triangle zone having a set of comer points defined by the red, green, and blue primary colors but outside a white zone having comers with coordinates (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375) in the CIE 1931 chromaticity chart.

3. The system of claim 2, wherein the red color lies within a red zone defined by a set of comer points with coordinates (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 green zone defined by a set of corner 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 blue zone defined by a set of comer 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).

4. The system of claim 1, wherein the primary red, green, and blue colors have coordinates in the CIE chart (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325), respectively.

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

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

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

8. The system of claim 1, further comprising:

a light pipe.

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

10. The system of claim 8, wherein the light pipe is positioned after the light pipe at the propagation path of the light from the light source.

11. 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 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.

12. 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.

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

14. 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.

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

16. The system of claim 1, wherein the color of the color rendering segment lies within a hexagon G₂Y₂R₂M₂B₂C₂, 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.

17. The system of claim 1, wherein the color rendering filter has a color that lies within a sector between radial lines NC₁ and NC₂ in the CIE 1931 chromaticity chart but outside a white zone having comers with coordinates (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375), and with exclusion of colors belonging to a yellow zone having corners 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 first wavelength threshold having a value of 610 nanometers, while C₂ corresponds to a second wavelength threshold having a value of 546 nanometers.

18. The system of claim 17, wherein the C₁ and C₂ have coordinates in the CIE chart of (0.666, 0.334) and (0.237, 0.718), respectively.

19. The system of claim 17, 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

20. The system of claim 17, wherein point N has the coordinates of (0.296, 0.322) in the CIE chromaticity chart.

21. The system of claim 17, wherein the color rendering segment has a color that lies within an orange 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).

22. The system of claim 17, wherein the color rendering segment has a color that lies within a yellow-green 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).

23. The system of claim 17, wherein the color rendering segment has a color that lies within a sub-cyan 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).

24. The system of claim 17, wherein the color rendering filter having a color that lies within a sector between radial lines NA₁ and NA₂ in the CIE 1931 chromaticity chart but outside a white zone having comers with coordinates (0.355, 0.355);

(0.305, 0.305);

(0.285, 0.325); and

(0.335, 0.375), and with exclusion of a sub-cyan zone having comers 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 and A₂ have the coordinates of (0.373, 0.624) and (0.169, 0.007), respectively.

25. The system of claim 24, wherein point N has the coordinates of (0.296, 0.322) in the CIE chromaticity chart.

26. The system of claim 24, 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 24, 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).

28. The system of claim 27, wherein the threshold has a value of 0.0017.