BACKLIGHT UNIT HAVING LIGHT EMITTING DIODE

• US 20120229039A1
• Filed: 08/10/2011
• Published: 09/13/2012
• Est. Priority Date: 03/09/2011
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: KANG, MOONSHIK
• Granted Patent: US 8,994,701 B2
• Time in Patent Office: Days
• US Class Current: 315/193
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines

Abstract

A backlight unit has a Light Emitting Diode (LED). The backlight unit includes a base member, and a light source unit provided on the base member and including p light source blocks, where p is a natural number equal to or greater than 2. The light source blocks are sequentially arranged to emit light, and each of the light source blocks includes at least one LED package. The LED package includes an LED configured to generate light in response to a driving voltage applied from the outside. A main lead is connected to the LED and configured to apply the driving voltage to the LED. At least one sub lead is separated from the main lead and configured to provide the driving voltage to an adjacent light source block.

Claims

1. A backlight unit for a Light Emitting Diode (LED) display device, the backlight unit comprising:

a base member; and

a light source unit on the base member and comprising p light source blocks sequentially arranged to emit light, where p is a natural number equal to or greater than 2,

wherein each of the light source blocks comprises;

at least one LED package comprising an LED configured to generate light in response to a driving voltage applied from the outside,

a main lead connected to the LED and configured to apply the driving voltage to the LED, and

at least one sub lead separated from the main lead and configured to provide the driving voltage to an adjacent light source block.

2. The backlight unit of claim 1, wherein the LED package further comprises a body unit configured to fix the LED, the main lead, and the sub lead.

3. The backlight unit of claim 2, wherein the LED package further comprises a penetration hole provided in the body unit and configured to expose the LED toward a surface of the base member, and a heat sink provided in the penetration hole.

4. The backlight unit of claim 2, wherein

the LED comprises a first electrode and a second electrode,

the main lead comprises a first main lead connected to the first electrode, and a second main lead separated from the first main lead and connected to the second electrode, and

the driving voltage is applied to the first main lead, and a reference voltage lower than the driving voltage is applied to the second main lead.

5. The backlight unit of claim 4,

further comprising a ground wiring to which the reference voltage is applied from the outside,

wherein the second main lead is connected to the ground wiring.

6. The backlight unit of claim 4,

further comprising a heat release chassis combined to an opposed surface of the base member,

wherein the opposed surface faces a surface on which the light source blocks are situated.

7. The backlight unit of claim 6, wherein:

the reference voltage is applied to the heat release chassis, and

the second main lead is connected to the heat release chassis.

8. The backlight unit of claim 1, each of the light source blocks includes k LED packages connected in series, where k is a natural number equal to or greater than 2.

9. The backlight unit of claim 8, wherein:

multiple sub leads are provided,

the main lead included in a first LED package of an nth light source block among the light source blocks is connected to one of the sub leads included in a kth LED package of an (n−

1)th light source block, where n is a natural number equal to or greater than 2, and

the sub leads included in the first LED package of the nth light source block are connected to the sub leads included in the kth LED package of the (n−

1)th light source block.

10. The backlight unit of claim 9, wherein the number of connections between the sub leads included in the first LED package of the nth light source block and the number sub leads included in the kth LED package of the (n−

1)th light source block is greater by 1 than the number of connections between the sub leads included in the kth LED package of the nth light source block and the sub leads included in a first LED package of an (n+1)th light source block.

11. The backlight unit of claim 9, wherein each of the LED packages comprises as much as (p−

1) sub leads.

12. The backlight unit of claim 8, further comprising:

a first wiring provided to the base member and configured to connect the sub leads of adjacent LED packages in each of the light source blocks to each other; and

a second wiring configured to connect the main leads of the adjacent LED packages to each other.

13. The backlight unit of claim 12,

wherein multiple sub leads are provided, and

further comprising:

a third wiring provided to the base member and configured to connect the main lead included in a first LED package of a nth light source block among the p light source blocks to one of the sub leads included in a kth LED package of a (n−

1)th light source block, where n is a natural number equal to or greater than 2; and

fourth wirings configured to connect the sub leads included in the first LED package of the nth light source block to the sub leads included in the kth LED package of the (n−

1)th light source block.

14. The backlight unit of claim 1, further comprising a driving circuit configured to provide the driving voltage to the light source blocks.

15. The backlight unit of claim 14, wherein the driving circuit comprises:

a voltage boosting circuit configured to boost an externally-applied input voltage and output the driving voltage;

a switching unit configured to selectively provide the driving voltage to the light source blocks; and

a dimming circuit configured to turn on and off the switching unit.

16. The backlight unit of claim 15, wherein the switching unit comprises as many switching elements as the number of the light source blocks.

17. The backlight unit of claim 1, further comprising a light guide plate configured to receive light emitted from the light source unit through at least one side and emit the received light through an emitting surface.

18. The backlight unit of claim 17, wherein a light emitting surface of the LED package is substantially parallel with the one side of the light guide plate.

19. The backlight unit of claim 18, further comprising:

a diffusion sheet on the emitting surface of the light guide plate; and

a reflective sheet under a surface facing the emitting surface of the light guide plate.

20. A light emitting diode (LED) backlight unit for an LED display device, the LED backlight unit comprising:

multiple light source blocks mounted on a base member, each light source block comprising multiple LED packages, each LED package having a body unit for mounting an LED on the base member,

wherein the body unit comprises a groove part having tapered walls, the LED being mounted within the groove part such that light emitted by the LED can be both transmitted directly from body unit and also reflected by the walls of groove part and then transmitted from body unit, and

wherein a main lead is connected to the LED and configured to apply a driving voltage to the LED and at least one sub lead is separated from the main lead and configured to provide the driving voltage to an adjacent light source block.