Backlight unit

• US 9,519,184 B2
• Filed: 06/27/2014
• Issued: 12/13/2016
• 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
• Application Number:
  US14/317,204
• Publication Number:
  US 20140313696A1
• Time in Patent Office: 900 Days
• US Class Current: 1/1
• 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. A lighting device comprising:

a plurality of light emitting diode (LED) chips that emit light;

a plurality of LED modules each having a printed circuit board (PCB) which supports and drives the plurality of LED chips projecting from top surfaces of the printed circuit board; and

an optical sheet that is attached to the to surface of each printed circuit board included in each of the plurality of LED modules, respectively, wherein each of the optical sheets have a same size as each of the printed circuit boards or a smaller size than each of the printed circuit boards, respectively,

wherein 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, and

wherein the plurality of LED modules include a plurality of white LED chips, the plurality of white LED chips each include a blue LED, a red phosphor, and a green phosphor to emit white light, color coordinates of red light emitted from the red phosphor 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 phosphor are positioned within a region surrounded by four vertexes of (0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5318), and (0.2555, 0.5030).

2. The lighting device of claim 1, wherein the plurality of LED chips are arranged in a matrix shape composed of two or more rows and two or more columns.

3. The lighting device of claim 1, wherein the plurality of LED chips in each of the plurality of blocks are connected to each other in series.

4. The lighting device of claim 1, 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.

5. The lighting device of claim 1, 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.

6. The lighting device of claim 1, 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.

7. The lighting device of claim 1, 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.

8. The lighting device of claim 1, wherein the red phosphor includes a nitride-based or sulfide-based phosphor.

9. The lighting device of claim 1, wherein the green phosphor includes any one of silicate-based, sulfide-based and nitride-based phosphors.

10. The lighting device of claim 1, wherein the plurality of LED modules are arranged outside of a predetermined region of a central part.

11. The lighting device of claim 1, wherein the lighting device is a backlight unit.

15. The lighting device of claim 1, further comprising a plurality of heat radiating pads that are attached to rear surfaces of the plurality of LED modules, respectively.

12. 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 each having a printed circuit board (PCB) which supports and drives the plurality of LED chips projecting from top surfaces of the printed circuit board; and

an optical sheet that is attached to the to surface of each printed circuit board included in each of the plurality of LED modules, respectively, wherein each of the optical sheets have a same size as each of the printed circuit boards or a smaller size than each of the printed circuit boards, respectively,

wherein 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, and

wherein the plurality of LED modules include a plurality of white LED chips, the plurality of white LED chips each include a blue LED, a red phosphor, and a green phosphor to emit white light, color coordinates of red light emitted from the red phosphor 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 phosphor 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).

13. The display device of claim 12, wherein the plurality of LED chips are arranged in a matrix shape composed of two or more rows and two or more columns.

14. The display device of claim 12, wherein the plurality of LED modules are arranged outside of a predetermined region of a central part.

16. The display device of claim 12, wherein the backlight unit is an edge-type backlight unit.