Backlight module and method of manufacture using complementary light sources having the same color

• US 7,950,814 B2
• Filed: 11/11/2008
• Issued: 05/31/2011
• Est. Priority Date: 12/06/2007
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Chang, Ya-Hsien, Lin, Yu-Kai
• Primary Examiner(s): Bruce; David V
• Application Number:
  US12/268,494
• Publication Number:
  US 20090147501A1
• Time in Patent Office: 931 Days
• Field of Search: 362/97.1, 362/97.2, 362/97.3, 362/231
• US Class Current: 362/97.3
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources

Abstract

A backlight module includes an optical film set and a plurality of light source sets having a first light source and a second light source. The first light source generates a first chromaticity light while the second light source generates a second chromaticity light. The first chromaticity light mixes with the second chromaticity light in the space between the light source sets and the optical film set and then enters the optical film set. The first chromaticity light and the second chromaticity light have their own spectrum and both spectra fall into a first color region of the CIE 1931 color space. Within the first color region, the spectrum of the first chromaticity light is close to a second color region while the spectrum of the second chromaticity light is close to a third color region.

Claims

1. A backlight module comprising:

an optical film set having a light incident plane; and

a plurality of light source sets disposed correspondingly to the light incident plane of the optical film set, wherein each of the light source sets includes;

at least one first light source generating a first chromaticity light; and

at least one second light source generating a second chromaticity light, the first chromaticity light and the second chromaticity light being mixed and enter the light incident plane;

wherein a spectrum of the first chromaticity light and a spectrum of the second chromaticity light both belong to a first color region, the spectrum of the first chromaticity light is close to a second color region while the spectrum of the second chromaticity light is close to a third color region.

2. The backlight module of claim 1, wherein the first chromaticity light and the second chromaticity light are respectively a white light, the first color region is a white light region and is situated in an area enclosed by (0.23, 0.21), (0.32, 0.31), (0.32, 0.21), and (0.23, 0.31) in the CIE1931 color space.

3. The backlight module of claim 2, wherein the second color region is a yellow light region and the third color region is a blue light region.

4. The backlight module of claim 1, wherein the first light source and the second light source have an identical phosphor, a concentration of the phosphor of the first light source is different to a concentration of the phosphor of the second light source.

5. The backlight module of claim 1, wherein the first color region has a target spectrum distribution, the first chromaticity light and the second chromaticity light mix together and have a spectrum falling into the target spectrum distribution, a coordinate difference in the CIE1931 color space between the target spectrum distribution and the spectrum of the first chromaticity light as well as the spectrum of the second chromaticity light is between (0.036, 0.056) and (−

0.036, −

0.056).

6. The backlight module of claim 5, wherein the coordinate difference in the CIE1931 color space between the target spectrum distribution and the spectrum of the first chromaticity light as well as the spectrum of the second chromaticity light is between (0.018, 0.028) and (−

0.018, −

0.028).

7. The backlight module of claim 6, wherein the coordinate difference in the CIE1931 color space between the target spectrum distribution and the spectrum of the first chromaticity light as well as the spectrum of the second chromaticity light is between (0.01, 0.014) and (−

0.01, −

0.014).

8. The backlight module of claim 5, wherein the target spectrum distribution is situated in an area enclosed by (0.225, 0.205), (0.315, 0.305), (0.225, 0.305), and (0.315, 0.205) in the CIE1931 color space.

9. The backlight module of claim 8, wherein the target spectrum distribution is situated in an area enclosed by (0.288, 0.263), (0.296, 0.276), (0.291, 0.288), and (0.283, 0.272) in the CIE1931 color space.

10. The backlight module of claim 5, wherein the light source set 300 includes a target chromaticity light source generating a target chromaticity light, a spectrum of the target chromaticity light falls into the target spectrum distribution, the target chromaticity light, the first chromaticity light and the second chromaticity light mix together and enter the light incident plane 110 of the optical film set 100.

11. The backlight module of claim 1, wherein the light source set 300 further includes a package entity, the first light source 310 includes a first LED (Light Emitting Diode) chip and the second light source 320 includes a second LED chip, the first LED chip and the second LED chip are both packaged in the package entity.

12. The backlight module of claim 1 further comprising a base plate in parallel with the light incident plane of the optical film set, wherein the light source set 300s are disposed on the base plate.

13. The backlight module of claim 12, wherein when a spacing between the adjacent light source sets is greater than 15 mm, a ratio of distance between the light source set and the optical film set to the spacing between the adjacent light source sets is greater than 0.4.

14. The backlight module of claim 12, wherein the light source sets are disposed in a matrix on the base plate.

15. The backlight module of claim 12, wherein the first light source and the second light source of the light source set have an aligning direction, the aligning direction of each of the light source sets is rotated in an angle relative to the aligning direction of the adjacent light source set.

16. The backlight module of claim 12, wherein the light source set includes a target chromaticity light source generating a target chromaticity light, the target chromaticity light source, the first light source and the second light source are arranged in a triangle pattern, the target chromaticity light, the first chromaticity light and the second chromaticity light mix together and enter the light incident plane of the optical film set.

17. The backlight module of claim 1, wherein an illuminated region on the optical film set by the first chromaticity light generated by the first light source overlaps an illuminated region on the optical film set by the second chromaticity light generated by the second chromaticity light source of the light source set and by the second chromaticity light generated by the second chromaticity light source of the adjacent light source set.

18. A manufacture method of backlight modules comprising:

forming a plurality of light source sets, wherein each of the light source sets includes;

at least one first light source generating a first chromaticity light; and

at least one second light source generating a second chromaticity light, wherein a spectrum of the first chromaticity light and a spectrum of the second chromaticity light belong to a first color region, the spectrum of the first chromaticity light is close to a second color region while the spectrum of the second chromaticity light is close to a third color region;

disposing the plurality of light source sets corresponding to a light incident plane of the optical film set, thus the first chromaticity light and second chromaticity light mix together and enter the light incident plane 110 of the optical film set.

19. The manufacture method of claim 18 further comprising:

manufacturing a plurality of white LEDs in one process;

selecting part of the white LEDs to be the first light sources; and

selecting part of the white LEDs to be the second light sources.

20. The manufacture method of claim 18, wherein the light source set forming step further includes assigning the first color region to a white light region, the white light region is situated in an area enclosed by (0.23, 0.21), (0.32, 0.31), (0.23, 0.31), and (0.32, 0.21) in the CIE1931 color space.

21. The manufacture method of claim 18, wherein the light source set forming step further includes assigning a target spectrum distribution in the first color region, the first chromaticity light and the second chromaticity light mix together and have a spectrum falling into the target spectrum distribution, a coordinate difference in the CIE1931 color space between the target spectrum distribution and the spectrum of the first chromaticity light as well as the spectrum of the second chromaticity light is between (0.036, 0.056) and (−

0.036, −

0.056).

22. The manufacture method of claim 21, wherein the light source set forming step further includes setting the coordinate difference in the CIE1931 color space between the target spectrum distribution and the spectrum of the first chromaticity light as well as the spectrum of the second chromaticity light between (0.018, 0.028) and (−

0.018, −

0.028).

23. The manufacture method of claim 22, wherein the light source set forming step further includes setting the coordinate difference in the CIE1931 color space between the target spectrum distribution and the spectrum of the first chromaticity light as well as the spectrum of the second chromaticity light between (0.01, 0.014) and (−

0.01, −

0.014).

24. The manufacture method of claim 21, wherein the light source set forming step further includes assigning the target spectrum distribution to be an area of the CIE1931 color space enclosed by (0.225, 0.205), (0.315, 0.305), (0.225, 0.305) and (0.315, 0.205).

25. The manufacture method of claim 24, wherein the light source set forming step further includes assigning the target spectrum distribution to be an area of the CIE1931 color space enclosed by (0.288, 0.263), (0.288, 0.263), (0.288, 0.263) and (0.283, 0.272).

26. The manufacture method of claim 21, wherein the light source set forming step further includes disposing a target chromaticity light source to generate a target chromaticity light, the target chromaticity light falls into the target spectrum distribution.

27. The manufacture method of claim 18, wherein the light source set forming step further includes packaging the first light source and the second light source in a package entity.