Backlight unit and liquid crystal display device including the same

• US 9,658,389 B2
• Filed: 12/01/2015
• Issued: 05/23/2017
• Est. Priority Date: 12/03/2014
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Jeoung, Do-Young, Kim, Chang-Il
• Primary Examiner(s): Dudek, James
• Application Number:
  US14/955,493
• Publication Number:
  US 20160161667A1
• Time in Patent Office: 539 Days
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0088 of the light guide or other optical sheets in the package

Abstract

Disclosed is a backlight unit and LCD device having a fixing device attached to a bottom cover and a guide panel to prevent the guide panel from shifting and detaching from the bottom cover. The backlight unit comprises a bottom cover having a bottom portion including a first hole, and a side portion having a second hole; a light guide plate on the bottom portion of the bottom cover; at least one optical sheet on the light guide plate; a guide panel adjacent the guide plate and the optical sheet; and a fixing device. The fixing device includes a horizontal portion; and a side portion extending perpendicularly from the horizontal portion. The side portion includes second protrusion portions extending inward from an edge of the side portion and parallel to the horizontal portion, and supporting portions extending vertically from the side portion at distal ends of the side portion.

Claims

1. A backlight unit, comprising:

a bottom cover having a bottom portion including a first hole, and a side portion having a second hole;

a light guide plate on the bottom portion of the bottom cover;

at least one optical sheet on the light guide plate;

a reflection sheet below the light guide plate;

a guide panel adjacent to the light guide plate and the at least one optical sheet; and

a fixing device, wherein the fixing device includes;

a horizontal portion including a first protrusion portion protruding substantially perpendicularly from an edge of the horizontal portion; and

a side portion extending perpendicularly from the horizontal portion, the side portion including second protrusion portions extending inward from an edge of the side portion and parallel to the horizontal portion, and supporting portions extending further vertically from the side portion at distal ends of the side portion,

wherein the first protrusion portion couples the horizontal portion of the fixing device to the bottom cover via the first hole.

2. The backlight unit of claim 1, wherein the reflection sheet, the light guide plate and the at least one optical sheet are located in an accommodating space of the bottom cover.

3. The backlight unit of claim 1, wherein the guide panel comprises:

a first side portion, and a first supporting portion extending from the first side portion toward the light guide plate.

4. The backlight unit of claim 3, wherein the first side portion contacts a side of the bottom cover and an upper surface of the at least one optical sheet.

5. The backlight unit of claim 4, wherein the first side portion includes a third hole.

6. The backlight unit of claim 1, wherein the horizontal portion of the fixing device contacts a lower surface of the bottom cover.

7. The backlight unit of claim 3, wherein the side portion of the fixing device contacts the first side portion of the guide panel.

8. The backlight unit of claim 1, wherein the second protrusion portions of the fixing device are coupled to the guide panel via the third hole.

9. The backlight unit of claim 1, wherein the second protrusion portions are located between the supporting portions located at the distal ends of the side portion.

10. The backlight unit of claim 5, wherein the second protrusion portions of the fixing device are coupled to the guide panel and the bottom cover via the second and third holes.

11. The backlight unit of claim 1, wherein the horizontal portion and side portion of the fixing device correspond to non-light entering sides of the backlight unit.

12. The backlight unit of claim 1, wherein the reflection sheet reflects light from the light guide plate in a direction of the at least one optical sheet.

13. The backlight unit of claim 1, wherein a length of the first protrusion is equal to or less than a depth of the first hole in the bottom cover.

14. The backlight unit of claim 1, wherein the side portion of the fixing device is opposite the first protrusion portion.

15. A fixing device for attaching a backlight unit and a liquid crystal display panel, comprising:

a horizontal portion including a first protrusion portion protruding substantially perpendicularly from an edge of the horizontal portion; and

a side portion extending perpendicularly from the horizontal portion, the side portion including second protrusion portions extending inward from an edge of the side portion and parallel to the horizontal portion, and supporting portions extending further vertically from the side portion at distal ends of the side portion,

wherein the first protrusion portion couples the horizontal portion of the fixing device to the bottom cover via the first hole.

16. The fixing device of claim 15, wherein the side portion is opposite the first protrusion portion.

17. The fixing device of claim 15, wherein the second protrusion portions are located between the supporting portions.

18. The fixing device of claim 15, wherein the supporting portions extend vertically to a length of a first side portion of a guide panel.

19. The fixing device of claim 15, wherein a length of the first protrusion is greater than a depth of a first hole in a bottom cover of the backlight unit.

20. A liquid crystal display device, comprising:

a liquid crystal panel having a thin film transistor substrate and color filter substrate coupled to each other and a liquid crystal layer therebetween; and

a backlight unit, wherein the liquid crystal panel is on an upper surface of the backlight unit, the backlight unit comprising;

a bottom cover having a bottom portion including a first hole, and a side portion having a second hole;

a light guide plate on the bottom portion of the bottom cover;

at least one optical sheet on the light guide plate;

a reflection sheet below the light guide plate;

a guide panel adjacent to the light guide plate and the at least one optical sheet; and

a fixing device, wherein the fixing device includes;

a horizontal portion including a first protrusion portion protruding substantially perpendicularly from an edge of the horizontal portion; and

a side portion extending perpendicularly from the horizontal portion, the side portion including second protrusion portions extending inward from an edge of the side portion and parallel to the horizontal portion, and supporting portions extending further vertically from the side portion at distal ends of the side portion,

wherein the first protrusion portion couples the horizontal portion of the fixing device to the bottom cover via the first hole.