Backlight unit

• US 8,764,212 B2
• Filed: 03/09/2009
• Issued: 07/01/2014
• Est. Priority Date: 07/19/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Dae Yeon, Jeong, Young June, Hahm, Hun Joo, Shin, Jae Hong, Shin, Chang Ho
• Primary Examiner(s): BANNAN, JULIE A
• Application Number:
  US12/400,317
• Publication Number:
  US 20090168399A1
• Time in Patent Office: 1,940 Days
• Field of Search: 362/231, 362/612, 362/97.3, 362/249.02
• US Class Current: 362/97.3
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21K 9/60 Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133628 with cooling means
• CPC Class Codes: H05K 1/142 Arrangements of planar printed circuit boards in the same plane, e.g. auxiliary printed circuit insert mounted in a main printed circuit

Abstract

Provided is a backlight unit including a plurality of light emitting diodes (LEDs) that emit light; a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LEDs; a plurality of optical sheets that are attached to the top surfaces of the respective LED modules; and a plurality of heat radiating pads that are attached to the rear surfaces of the respective LED modules.

Claims

1. Alight emitting diode (LED) backlight unit comprising:

a plurality of LED chips that emit light;

a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LED chips;

a plurality of optical sheets that are attached to the top surfaces of the respective LED modules; and

a plurality of heat radiating pads that are attached to the rear surfaces of the respective LED modules,

wherein the plurality of LED modules include the plurality of LED chips arranged in a matrix shape composed of two or more rows and two or more columns and the plurality of LED chips are divided into a plurality of blocks which are separated from each other through printing circuit patterns in a circuit manner so as to be independently turned on/off,

each of the LED chips has a phosphor in order to emit white light, and

wherein the optical sheets and the heat radiating pads have the same size as the LED modules or a smaller size than the LED modules.

2. The LED backlight unit according to claim 1, wherein in case that the size of the LED backlight unit is 40, 46 or 52 inches, the number of LED modules is selected in the range of 6 to 12 and in the case of 57 inch, the number of LED modules is selected in the range of 6 to 20.

3. The LED backlight unit according to claim 1, wherein in case that the size of the LED backlight unit is 40 inch, the number of LED modules is selected in the range of 6 to 12, the number of blocks for each LED module is selected in the range of 4 to 14 and the number of LED chips for each block is selected in the range of 6 to 24.

4. The LED backlight unit according to claim 1, wherein in case that the size of the LED backlight unit is 46 inch, the number of LED modules is selected in the range of 6 to 12, the number of blocks for each LED module is selected in the range of 5 to 15 and the number of LED chips for each block is selected in the range of 6 to 24.

5. The LED backlight unit according to claim 1, wherein in case that the size of the LED backlight unit is 52 inch, the number of LED modules is selected in the range of 6 to 12, the number of blocks for each LED module is selected in the range of 6 to 28 and the number of LED chips for each block is selected in the range of 6 to 24.

6. The LED backlight unit according to claim 1, wherein in case that the size of the LED backlight unit is 57 inch, the number of LED modules is selected in the range of 6 to 20, the number of blocks for each LED module is selected in the range of 6 to 28 and the number of LED chips for each block is selected in the range of 6 to 24.

7. The LED backlight unit according to claim 1, wherein the LED chips of each block are connected to each other in series.

8. The LED backlight unit according to claim 1, wherein the LED chips include blue LEDs, red phosphors and green phosphors to emit the white light.

9. The LED backlight unit according to claim 8, wherein the red phosphor includes a nitride-based or sulfide-based phosphor.

10. The LED backlight unit according to claim 8, wherein the green phosphor includes any one of silicate-based, sulfide-based and nitride-based phosphors.

36. The LED backlight unit according to claim 1, wherein each of the plurality of LED modules comprises first LED chips, among the plurality of LED chips, arranged in a matrix shape composed of two or more rows and two or more columns, and the first LED chips are divided into the plurality of blocks.

38. The LED backlight unit according to claim 1, wherein the plurality of LEDs are continuously arranged in a triangle or rectangle shape, and a distance between LEDs which are adjacent to each other in a row or column direction is set in the range of 8.2 to 70 mm.

11. A light emitting diode (LED) backlight unit comprising:

a plurality of LED chips that emit light;

a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LED chips,

a plurality of optical sheets that are attached to the top surfaces of the respective LED modules; and

a plurality of heat radiating pads that are attached to the rear surfaces of the respective LED modules,

wherein the plurality of LED modules include a plurality of white LED chips arranged in a matrix shape composed of two or more rows and two or more columns, the white LED chips include blue LEDs, red phosphors and green phosphors, color coordinates of red light emitted from the red phosphors are positioned within a region surrounded by four vertexes of (0.6448, 0.4544), (0.8079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) on the basis of the CIE 1931 color coordinate system, and color coordinates of green light emitted from the green phosphors are positioned within a region surrounded by four vertexes of (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316), and (0.2555, 0.5030), and

wherein the optical sheets and the heat radiating pads have the same size as the LED modules or a smaller size than the LED modules.

12. The LED backlight unit according to claim 11, wherein the plurality of LED chips include an LED unit composed of arbitrary LED chips which are disposed at the shortest distance from each other and a center luminous intensity of the LED unit corresponds to 80 to 120% of the average of luminous intensities of the LED chips.

13. The LED backlight unit according to claim 11, wherein the plurality of LED chips are continuously arranged in a triangle shape and a distance between first and second LED chips, which are disposed in the same column and are adjacent to each other, is set in the range of 20 to 140 mm.

14. The LED backlight unit according to claim 11, wherein the plurality of LED chips are continuously arranged in a triangle shape and a distance between LED chips which are adjacent to each other in a row or column direction is set in the range of 8.2 to 70 mm.

15. The LED backlight unit according to claim 11, wherein the plurality of LED chips are continuously arranged in a rectangle shape and distances between LED chips, which are adjacent to each other, are set in the range of 8.2 to 70 mm.

16. The LED backlight unit according to claim 11, wherein the plurality of LED chips are continuously arranged in a rectangle shape and an angle between the column direction where the LED chips are arranged and a position where the LED is disposed is formed in the range of 70 to 110 degrees.

17. The LED backlight unit according to claim 11, wherein the plurality of LED modules are divided into a plurality of blocks which are separated from each other through printing circuit patterns in a circuit manner so as to be independently turned on/off.

18. The LED backlight unit according to claim 11, wherein the plurality of LED modules are divided into a plurality of blocks which are separated from each other through printing circuit patterns in a circuit manner so as to be independently turned on/off and the LED chips of each block are connected to each other in series.

19. The LED backlight unit according to claim 11, wherein the red phosphor includes a nitride-based or sulfide-based phosphor.

20. The LED backlight unit according to claim 11, wherein the green phosphor includes any one of silicate-based, sulfide-based and nitride-based phosphors.

21. A light emitting diode (LED) backlight unit comprising:

a plurality of LED chips that emit white light;

a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LED chips;

a plural of optical sheets that are attached to the top surfaces of the respective LED modules; and

a plurality of eat radiating pads that are attached to the rear surfaces of the respective LED modules,

wherein the plurality of LED modules are divided into a plurality of blocks which are separated from each other through printing circuit patterns in a circuit manner so as to be independently turned on/off and the plurality of LED modules are arranged outside of a predetermined region of a central part,

each of the LED chips has a phosphor in order to emit white light, and

wherein the optical sheets and the heat radiating pads have the same size as the LED modules or a smaller size than the LED modules.

22. The LED backlight unit according to claim 21, wherein the LED chips of each block are connected to each other in series.

23. The LED backlight unit according to claim 21, wherein distances between LED chips, which are adjacent to each other, are set in the range of 8.2 to 70 mm.

24. The LED backlight unit according to claim 21, wherein the LED chips include blue LEDs, red phosphors and green phosphors to emit the white light.

25. The LED backlight unit according to claim 24, wherein the red phosphor includes a nitride-based or sulfide-based phosphor.

26. The LED backlight unit according to claim 24, wherein the green phosphor includes any one of silicate-based, sulfide-based and nitride-based phosphors.

37. The LED backlight unit according to claim 21, wherein the LED chips include blue LEDs, red phosphors and green phosphors, color coordinates of red light emitted from the red phosphors are positioned within a region surrounded by four vertexes of (0.6448, 0.4544), (0.8079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) on the basis of the CIE 1931 color coordinate system, and color coordinates of green light emitted from the green phosphors are positioned within a region surrounded by four vertexes of (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316), and (0.2555, 0.5030).

27. A display device comprising:

a display panel; and

a backlight unit which irradiates light to the display panel,

wherein the backlight unit comprises;

a plurality of LED chips that emit light;

a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LED chips;

a plurality of optical sheets that are attached to the top surfaces of the respective LED modules; and

a plurality of heat radiating pads that are attached to the rear surfaces of the respective LED modules,

wherein the plurality of LED modules include the plurality of LED chips arranged in a matrix shape composed of two or more rows and two or more columns and the plurality of LED chips are divided into a plurality of blocks which are separated from each other through printing circuit patterns in a circuit manner so as to be independently turned on/off,

each of the LED chips has a phosphor in order to emit white light, and

wherein the optical sheets and the heat radiating pads have the same size as the LED modules or a smaller size than the LED modules.

28. The display device of claim 27, wherein the display panel is a liquid crystal panel.

29. The display device of claim 27, further comprising a driving circuit which drives the backlight unit.

30. A display device comprising:

a display panel; and

a backlight unit which irradiates light to the display panel,

wherein the backlight unit comprises;

a plurality of LED chips that emit light;

a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LED chips,

a plurality of optical sheets that are attached to the top surfaces of the respective LED modules; and

a plurality of heat radiating pads that are attached to the rear surfaces of the respective LED modules,

wherein the plurality of LED modules include a plurality of white LED chips arranged in a matrix shape composed of two or more rows and two or more columns, the white LED chips include blue LEDs, red phosphors and green phosphors, color coordinates of red light emitted from the red phosphors are positioned within a region surrounded by four vertexes of (0.6448, 0.4544), (0.8079, 0.2920), (0.6427, 0.2905) and (0.4794, 0.4633) on the basis of the CIE 1931 color coordinate system, and color coordinates of green light emitted from the green phosphors are positioned within a region surrounded by four vertexes of (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316), and (0.2555, 0.5030), and

wherein the optical sheets and the heat radiating pads have the same size as the LED modules or a smaller size than the LED modules.

31. The display device of claim 30, wherein the display panel is a liquid crystal panel.

32. The display device of claim 30, further comprising a driving circuit which drives the backlight unit.

33. A display device comprising:

a display panel; and

a backlight unit which irradiates light to the display panel,

wherein the backlight unit comprises;

a plurality of LED chips that emit white light;

a plurality of LED modules having a printed circuit board (PCB) which supports and drives the plurality of LED chips; and

a plurality of optical sheets that are attached to the top surfaces of t respective LED modules; and

a plurality of heat radiating pads that are attached to the rear surfaces of the respective LED modules,

wherein the plurality of LED modules are divided into a plurality of blocks which are separated from each other through printing circuit patterns in a circuit manner so as to be independently turned on/off and the plurality of LED modules are arranged outside of a predetermined region of a central part,

each of the LED chips has a phosphor in order to emit white light, and

wherein the optical sheets and the heat radiating pads have the same size as the LED modules or a smaller size than the LED modules.

34. The display device of claim 33, wherein the display panel is a liquid crystal panel.

35. The display device of claim 33, further comprising a driving circuit which drives the backlight unit.