LED backlight device with deviated LED pitch

• US 20080068861A1
• Filed: 09/14/2006
• Published: 03/20/2008
• Est. Priority Date: 09/14/2006
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Peng, Chung, Chou, Shen-Hong, Lin, Yu-Kai, Tseng, Shin-Chin, Chen, Chih-Kuang
• Granted Patent: US 7,641,352 B2
• Time in Patent Office: Days
• US Class Current: 362/613
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity

Abstract

A backlight unit usable in a liquid crystal display. In one embodiment, the backlight unit includes a substrate, a first plurality of light emitting elements positioned on the substrate, and a second plurality of light emitting elements positioned on the substrate, where the first plurality of light emitting elements positioned on the substrate are arranged in rows, such that two neighboring rows define a first pitch therebetween and the second plurality of light emitting elements positioned on the substrate are arranged in a row such that the row of the second plurality of light emitting elements is separated from the closest neighboring row of the first plurality of light emitting elements by a second pitch, where the first pitch is less than the second pitch.

Claims

1. A backlight unit for use in a liquid crystal display, comprising:

a substrate;

a first plurality of light emitting elements positioned on the substrate, wherein

the first plurality of light emitting elements are arranged in a plurality of rows, such that two neighboring rows define a first pitch therebetween; and

a second plurality of light emitting elements positioned on the substrate and arranged in a row such that the row of the second plurality of light emitting elements is separated from the closest neighboring row of the first plurality of light emitting elements by a second pitch;

wherein the first pitch is less than the second pitch.

2. The backlight unit of claim 1, wherein the first pitch is less than the second pitch and the second pitch is less than three times of the first pitch.

3. The backlight unit of claim 1, wherein the substrate is formed with a first edge, a second edge, a third edge and a fourth edge, and wherein the first edge is opposite to the second edge, the third edge is opposite to the fourth edge, and the first edge is connected to the third edge.

4. The backlight unit of claim 3, wherein the row of the second plurality of light emitting elements is positioned between its closest neighboring row of the first plurality of light emitting elements and the first edge of the substrate.

5. The backlight unit of claim 4, further comprising a third plurality of light emitting elements positioned on the substrate and arranged in a row, and wherein the row of the third plurality of light emitting elements is positioned between its closest neighboring row of the first plurality of light emitting elements and the second edge of the substrate.

6. The backlight unit of claim 5, wherein the row of the third plurality of light emitting elements is separated from the closest neighboring row of the first plurality of light emitting elements by a third pitch, and wherein the first pitch is less than the third pitch.

7. The backlight unit of claim 6, wherein the first pitch is less than the third pitch and the third pitch is less than three times of the first pitch.

8. The backlight unit of claim 5, wherein the row of the second plurality of light emitting elements and the first edge of the substrate define a first distance therebetween, and the row of the third plurality of light emitting elements and the second edge of the substrate define a second distance therebetween, and wherein the first distance is less than the second pitch, and the second distance is less than the third pitch.

9. The backlight unit of claim 6, further comprising a fourth plurality of light emitting elements positioned on the substrate and arranged in a first column and a second column, and wherein the first column of the fourth plurality of light emitting elements is positioned between its closest neighboring column of the first plurality of light emitting elements and the third edge of the substrate, and the second column of the fourth plurality of light emitting elements is positioned between its closest neighboring column of the first plurality of light emitting elements and the fourth edge of the substrate.

10. The backlight unit of claim 9, wherein the first column of the fourth plurality of light emitting elements is separated from the closest neighboring column of the first plurality of light emitting elements by a fourth pitch, and the second column of the fourth plurality of light emitting elements is separated from the closest neighboring column of the first plurality of light emitting elements by a fifth pitch, and wherein the first pitch is less than the fourth pitch, and the first pitch is less than the fifth pitch.

11. The backlight unit of claim 10, wherein the fourth pitch is less than three times of the first pitch, and the fifth pitch is less than three times of the first pitch.

12. The backlight unit of claim 10, wherein the first column of the fourth plurality of light emitting elements and the third edge of the substrate define a third distance therebetween, and the second column of the fourth plurality of light emitting elements and the fourth edge of the substrate define a fourth distance therebetween, and wherein the third distance is less than the fourth pitch, and the fourth distance is less than the fifth pitch.

13. The backlight unit of claim 9, wherein each of the first plurality of light emitting elements, the second plurality of light emitting elements, the third plurality of light emitting elements and the fourth plurality of light emitting elements comprises at least three LED chips.

14. The backlight unit of claim 13, wherein the at least three LED chips comprise at least a first LED chip capable of emitting light in a red color, a second LED chip capable of emitting light in a blue color, and a third LED chip capable of emitting light in a green color.

15. The backlight unit of claim 9, wherein each of the first plurality of light emitting elements, the second plurality of light emitting elements, the third plurality of light emitting elements, and the fourth plurality of light emitting elements comprises a LED chip capable of emitting light in a white color.

16. A backlight unit for use in a liquid crystal display, comprising:

a substrate having a first zone and a second zone;

a first plurality of light emitting elements positioned in the first zone of the substrate and arranged in a plurality of rows, wherein two neighboring rows define a first pitch therebetween; and

a second plurality of light emitting elements positioned in the second zone of the substrate, wherein the first zone and the second zone are at least partially separated by a second pitch, and the first pitch is less than the second pitch.

17. The backlight unit of claim 16, wherein the first pitch is less than the second pitch and the second pitch is less than three times of the first pitch.

18. The backlight unit of claim 16, wherein the second plurality of light emitting elements are arranged in at least one row, substantially parallel to an edge of the substrate and separated by a distance therebetween, and wherein the distance is less than the second pitch.

19. The backlight unit of claim 18, wherein the distance is less than 1 mm.

20. The backlight unit of claim 16, wherein each of the first plurality of light emitting elements and the second plurality of light emitting elements comprises at least three LED chips.

21. The backlight unit of claim 20, wherein the at least three LED chips comprise at least a first LED chip capable of emitting light in a red color, a second LED chip capable of emitting light in a blue color, and a third LED chip capable of emitting light in a green color.

22. The backlight unit of claim 16, wherein each of the first plurality of light emitting elements and the second plurality of light emitting elements comprises a LED chip capable of emitting light in a white color.

23. A light emitting diode (LED) package structure for use in a liquid crystal display, comprising:

a substrate;

a first plurality of light emitting elements positioned on the substrate and arranged in a plurality of columns such that two neighboring columns define a first pitch therebetween;

a second plurality of light emitting elements positioned on the substrate and arranged in a column such that the column of the second plurality of light emitting elements is separated from the closest neighboring column of the first plurality of light emitting elements by a second pitch, wherein the first pitch is less than the second pitch;

a sidewall formed on the edges of the substrate; and

an optical film supported by the sidewall and positioned to face the first plurality of light emitting elements and the second plurality of light emitting elements.

24. The LED package structure of claim 23, wherein the first pitch is less than the second pitch and the second pitch is less than three times of the first pitch.

25. The LED package structure of claim 23, wherein the column of the second plurality of light emitting elements is positioned adjacent to an edge of the substrate, and defines a distance therebetween, and wherein the distance is less than the second pitch.

26. The LED package structure of claim 25, wherein the distance is less than 1 mm.

27. The LED package structure of claim 23, wherein the column of the second plurality of light emitting elements is positioned between its closest neighboring column of the first plurality of light emitting elements and the sidewall.

28. The LED package structure of claim 23, wherein the sidewall comprises a white sheet.

29. The LED package structure of claim 23, wherein each of the first plurality of light emitting elements and the second plurality of light emitting elements comprises at least three LED chips including at least a first LED chip capable of emitting light in a red color, a second LED chip capable of emitting light in a blue color, and a third LED chip capable of emitting light in a green color.

30. The backlight unit of claim 23, wherein each of the first plurality of light emitting elements and the second plurality of light emitting elements comprises a LED chip capable of emitting light in a white color.