Direct-type backlight unit having surface light source

• US 7,887,225 B2
• Filed: 07/05/2007
• Issued: 02/15/2011
• Est. Priority Date: 07/10/2006
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung LED Co., Ltd. (Samsung Electronics Co. Ltd.)
• Inventors: Han, Kyung Taeg, Lee, Won Joon, Park, Young Sam, Ahn, Ho Sik, Yeo, In Tae, Song, Chang Ho, Hahm, Hun Joo
• Primary Examiner(s): Payne; Sharon E
• Application Number:
  US11/822,331
• Publication Number:
  US 20080007939A1
• Time in Patent Office: 1,321 Days
• Field of Search: 362/561, 362/558, 362/555, 362/511, 362/545
• US Class Current: 362/561
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/52 Encapsulations

Abstract

In a direct-type backlight unit, a board has upper and lower surfaces defining a thickness therebetween. A plurality of unit light sources are disposed on the board. Here, in each of the unit light sources, a wiring pattern is formed on the board. A light emitting device is disposed on the wiring pattern to electrically connect thereto. A non-conductive side wall surrounds, without interruption, the light emitting device at a predetermined interval therefrom, the non-conductive side wall having a height lower than that of the light emitting device. Also, an encapsulant is formed in a dome shape inside the side wall. In this fashion, the light emitting devices are mounted on the board by a chip-on-board technique.

Claims

1. A direct-type backlight unit comprising:

a board having upper and lower surfaces defining a thickness therebetween; and

a plurality of unit light sources mounted on the board,

wherein each of the unit light sources comprises;

a wiring pattern formed on the board; and

a light emitting device disposed on the wiring pattern to electrically connect thereto;

a non-conductive side wall surrounding, without interruption, the light emitting device at a predetermined interval therefrom, the non-conductive side wall having a height lower than that of the light emitting device;

an encapsulant formed in a dome shape inside the side wall, the encapsulant comprising a transparent resin or a phosphor-mixed transparent resin; and

an opaque layer or a light diffusing layer formed on an upper end portion of the encapsulant, bounded by an area corresponding to the light emitting device, located in a vertical upward direction of the light emitting device and blocks light generated from the light emitting device from traveling in an upward direction to prevent a bright light spot from forming,

wherein the non-conductive side wall has a ring shaped structure with a through hole formed inside thereof and blocks a resin dispensed inside the non-conductive side wall from spreading out to form the dome shaped encapsulant.

6. The direct type backlight unit according to any one of claims 1, 2 and 4, wherein the wiring pattern in each of the unit light sources comprises:

upper terminals formed on the upper surface of the board where the light emitting device is disposed to be electrically connected to the light emitting device;

lower terminals formed on the lower surface of the board; and

internal connectors extending through the board to connect the upper and lower terminals together.

7. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein the light emitting device is electrically connected to the wiring pattern by wire bonding.

8. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein the light emitting device is electrically connected to the wiring pattern by flip chip bonding.

9. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein the side wall has a width that is 1.5% to 3% of a diameter of the encapsulant.

10. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein the side wall has a height that is 1% to 1.5% of a diameter of the encapsulant.

11. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein the encapsulant has a height that is 25% to 35% of a diameter thereof.

12. The direct-type backlight unit according to claim 11, wherein the encapsulant has a height that is ⅓

of a diameter thereof.

13. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein each of the unit light sources comprises at least two of the light emitting devices mounted inside the side wall.

14. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein some of the encapsulants in the light sources comprise a transparent resin and the other encapsulants comprise a phosphor-mixed transparent resin,

wherein the encapsulants comprising the transparent resin and the encapsulants comprising the phosphor-mixed transparent resin are mixed together.

15. The direct-type backlight unit according to any one of claims 1, 2 and 4, wherein the inside surface of the non-conductive side wall encircles and is in direct contact with an outside surface of the lower portion of the dome-shaped encapsulant.

2. A direct-type backlight unit comprising:

a board having upper and lower surfaces defining a thickness therebetween; and

a plurality of unit light sources mounted on the board,

wherein each of the unit light sources comprises;

a wiring pattern formed on the board; and

a light emitting device disposed on the wiring pattern to electrically connect thereto;

a non-conductive side wall surrounding, without interruption, the light emitting device on the hoard at a predetermined interval therefrom, the non-conductive side wall having a height lower than that of the light emitting device;

an encapsulant formed in a dome shape inside the side wall, the encapsulant comprising a transparent resin or a phosphor-mixed transparent resin; and

an opaque layer formed on an upper end portion of the encapsulant located in a vertical upward direction of the light emitting device and blocks light generated from the light emitting device from travelling in an upward direction to prevent a bright light spot from forming,

wherein the non-conductive side wall comprises a plurality of coating layers having an identical width, and

wherein the non-conductive side wall has a ring shaped structure with a through hole formed inside thereof and blocks a resin dispensed inside the non-conductive side wall from spreading out to form the dome shaped encapsulant.

3. The direct-type backlight unit according to claim 2, wherein the opaque layer is bounded by an area corresponding to the light emitting device.

4. A direct-type backlight unit comprising:

a board having upper and lower surfaces defining a thickness therebetween; and

a plurality of unit light sources mounted on the board,

wherein each of the unit light sources comprises;

a wiring pattern formed on the board; and

a light emitting device disposed on the wiring pattern to electrically connect thereto;

a non-conductive side wall surrounding, without interruption, the light emitting device at a predetermined interval therefrom, the non-conductive side wall being constructed of a plurality of coating layers and having a height lower than that of the light emitting device; and

an encapsulant formed in a dome shape inside the side wall,

wherein the side wall has an outer wall surface inclined toward an inner wall surface in such a way that the side wall has a width decreasing toward an apex.

5. The direct-type backlight unit according to claim 4, wherein the encapsulant comprises a transparent resin or a phosphor-mixed transparent resin.