Backlight unit and liquid crystal display apparatus including the same

• US 8,545,075 B2
• Filed: 08/17/2007
• Issued: 10/01/2013
• Est. Priority Date: 08/29/2006
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Park, Jun Seok
• Primary Examiner(s): Lee, Jong-Suk (James)
• Assistant Examiner(s): Tsidulko, Mark
• Application Number:
  US12/067,032
• Publication Number:
  US 20080219003A1
• Time in Patent Office: 2,237 Days
• Field of Search: 362/555, 362/26, 362/27, 362/600, 362/603, 362/609, 362/612
• US Class Current: 362/555
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors

Abstract

Provided are a backlight unit and a liquid crystal display apparatus including the same. The backlight unit comprises: a housing comprising an opening part; a module substrate in the opening part of the housing; a light emitting diode on the module substrate; and a reflection sheet in which the light emitting diode inserted thereto.

Claims

1. A backlight unit, comprising:

a housing;

a substrate formed in a single piece on the housing;

a plurality of light emitting diodes on the substrate;

a reflection sheet disposed on the substrate and including a plurality of holes;

a fixing means coupling the reflection sheet, the substrate and the housing, and configured to reflect light;

a plurality of optical receiving parts being formed of an optical fiber and disposed on the reflection sheet so as to detect light from the plurality of light emitting diodes; and

a plurality of transmission lines disposed on the reflection sheet and configured to transmit light detected at the plurality of optical receiving parts into a color optical receiving sensor,

wherein the plurality of light emitting diodes are inserted into the plurality of holes of the reflection sheet and a top portion of the plurality of light emitting diodes is protruded from a top surface of the reflection sheet,

wherein a top portion of the plurality of holes in the reflection sheet has a larger width than an under portion of the plurality of holes,

wherein the housing includes a slanted side surface and the slanted side surface of the housing is disposed at an outer side of the substrate, the plurality of light emitting diodes and the reflection sheet, so as to reflect light from the plurality of light emitting diodes,

wherein each of the plurality of light emitting diodes is located at the center of each of the plurality of holes of the reflection sheet, respectively, and a minimum tolerance of a distance between each of the plurality of light emitting diodes and each of the plurality of holes of the reflection sheet, respectively, is equal to 0.001 mm,

wherein a thickness of the reflection sheet is 50% to 90% of a height of the plurality of light emitting diodes,

wherein the top portion of each of the plurality of light emitting diodes is formed in a hemisphere shape, and

wherein each diameter of the plurality of holes at a center region in the reflection sheet is greater than each diameter of the plurality of holes at an outer region in the reflection sheet.

2. The backlight unit according to claim 1, wherein at least one of the plurality of light emitting diodes comprises at least one of a red light emitting diode (LED) chip, a green light emitting diode (LED) chip, and a blue light emitting diode (LED) chip.

3. The backlight unit according to claim 1, wherein a tilt angle of a circumference surface of the at least one of the plurality of holes in the reflection sheet is between 20 and 80°

.

4. The backlight unit according to claim 1, wherein a head portion of the fixing means is coated with white color and is protruded from the top surface of the reflection sheet.

5. The backlight unit according to claim 1, wherein the plurality of optical receiving parts and the plurality of transmission-line lines are formed of optical fibers having respectively different diameters.

6. The backlight unit according to claim 1, further comprising at least one optical sheet on the plurality of light emitting diodes and the reflection sheet.

7. The backlight unit according to claim 1, wherein a diameter of one of the plurality of holes in the reflection sheet gradually widens from a bottom toward the top surface of the reflection sheet, and

a circumference surface of at least one of the plurality of holes in the reflection sheet is a continuous surface.

8. The backlight unit according to claim 1, wherein a reflectivity of a head portion of the fixing means is over 70%.

9. The backlight unit according to claim 1, wherein the plurality of optical receiving parts are spaced apart from the plurality of holes that are inserted with the plurality of light emitting diodes.

10. The backlight unit according to claim 1, wherein one of the plurality of light emitting diodes has a red LED chip, a green LED chip, and a blue LED chip, which are arranged in a clockwise rotation and another of the plurality of light emitting diodes has a red LED chip, a blue LED chip, and a green LED chip, which are arranged in a clockwise rotation.

11. A liquid crystal display apparatus, comprising:

a liquid crystal panel;

an optical sheet under the liquid crystal panel; and

a light unit below the optical sheet,

wherein the light unit comprises;

a housing;

a substrate formed in a single piece in the housing;

a plurality of light emitting diodes on the substrate; and

a reflection sheet disposed on the substrate and including a plurality of holes;

a fixing means coupling the reflection sheet, the substrate and the housing, and configured to reflect light;

a plurality of optical receiving parts being formed of an optical fiber and disposed on the reflection sheet so as to detect light from the plurality of light emitting diodes; and

a plurality of transmission lines disposed on the reflection sheet and configured to transmit light detected at the plurality of optical receiving parts into a color optical receiving sensor,

wherein the plurality of light emitting diodes are inserted into the plurality of holes of the reflection sheet and a top potion of at least one of the plurality of light emitting diodes is protruded from a top surface of the reflection sheet,

wherein a top portion of at least one of the plurality of holes in the reflection sheet has a larger width than an under portion of the at least one of the plurality of holes,

wherein the housing includes a slanted side surface and the slanted side surface of the housing is disposed at an outer side of the substrate, the plurality of light emitting diodes and the reflection sheet, so as to reflect light from the plurality of light emitting diodes,

wherein each of the plurality of light emitting diodes is located at the center of each of the plurality of holes of the reflection sheet, respectively, and a minimum tolerance of a distance between each of the plurality of light emitting diodes and each of the plurality of holes of the reflection sheet, respectively, is equal to 0.001 mm,

wherein a thickness of the reflection sheet is 50% to 90% of a height of the plurality of light emitting diodes,

wherein the top portion of each of the plurality of light emitting diodes is formed in a hemisphere shape, and

wherein each diameter of the plurality of holes at a center region in the reflection sheet is greater than each diameter of the plurality of holes at an outer region in the reflection sheet.

12. The liquid crystal display apparatus according to claim 11, wherein a circumference surface of the plurality of holes is slanted 20 to 80°

outward with reference to a bottom of the reflection sheet.