Liquid crystal display device including backlight unit

1. A liquid crystal display device, comprising:

a main frame having a rectangular ring shape;

a reflecting plate on the main frame;

a light guide plate on the reflecting plate;

a light emitting diode (LED) assembly along at least one side of the main frame, the LED assembly having a plurality of LEDs and an LED printed circuit board (PCB), the LED PCB including a first portion having the plurality of LEDs thereon and a second portion perpendicular to the first portion;

an LED housing contacting the LED PCB;

a plurality of optical sheets on the light guide plate;

a liquid crystal panel on the plurality of optical sheets;

a bottom frame under the reflecting plate, the bottom frame including a horizontal plate contacting the reflecting plate and a sidewall perpendicular to the horizontal plate, wherein the LED housing directly contacts the sidewall for transmitting a heat from the LED PCB to the sidewall; and

a top frame covering a front edge portion of the liquid crystal panel, the top frame, the main frame and the bottom frame coupled to each other,

wherein the LED housing includes only a single vertical portion and a horizontal portion perpendicular to and extending from the vertical portion,

wherein the single vertical portion of the LED housing directly contacts the first portion of the LED PCB and the sidewall of the bottom frame,

wherein the horizontal portion of the LED housing directly contacts the second portion of the LED PCB and the horizontal plate of the bottom frame,

wherein the first portion of the LED PCB includes a base layer directly contacting the LED housing, an insulating layer directly on the base layer, and a conductive layer on the insulating layer, and the second portion of the LED PCB includes only the base layer, and

wherein a contact area between the second portion of the LED PCB and the horizontal portion of the LED housing is greater than a contact area between the first portion of the LED PCB and the vertical portion of the LED housing.

2. The device according to claim 1 , wherein the plurality of LEDs are separately disposed on the first portion of the LED PCB and the first portion facing a side surface of the light guide plate.

3. The device according to claim 1 , wherein each of the base layer and the conductive layer includes a metallic material and the insulating layer includes one of an epoxy resin and an epoxy ceramic.

4. The device according to claim 1 , wherein the LED PCB includes one of an FR-4 (flame retardant composition 4) PCB having a heat conduction material, a metal printed circuit board (MPCB) or a metal core printed circuit board (MCPCB).

5. The device according to claim 1 , wherein an area of the second portion of the LED PCB is greater than an area of the first portion of the LED PCB.

6. The device according to claim 1 , wherein the LED assembly is fixed to the LED housing with an adhesive.

7. The device according to claim 1 , wherein the LED housing includes a metal, and a surface of the LED housing is formed with an inorganic oxide layer.

8. The device according to claim 7 , wherein the inorganic oxide layer has a black color.

9. A liquid crystal display device, comprising:

a main frame having a rectangular ring shape;

a reflecting plate on the main frame;

a light guide plate on the reflecting plate;

a light emitting diode (LED) assembly along at least one side of the main frame, the LED assembly having a plurality of LEDs and an LED printed circuit board (PCB), the LED PCB including a first portion having the plurality of LEDs thereon and a second portion perpendicular to the first portion;

an LED housing contacting the LED PCB;

a plurality of optical sheets on the light guide plate;

a liquid crystal panel on the plurality of optical sheets;

a bottom frame under the reflecting plate, the bottom frame including a horizontal plate contacting the reflecting plate and a sidewall perpendicular to the horizontal plate, wherein the LED housing directly contacts the sidewall for transmitting a heat from the LED PCB to the sidewall; and

a top frame covering a front edge portion of the liquid crystal panel, the top frame, the main frame and the bottom frame coupled to each other,

wherein the LED housing includes only a single vertical portion,

wherein the single vertical portion of the LED housing directly contacts the first portion of the LED PCB and the sidewall of the bottom frame,

wherein the second portion of the LED PCB directly contacts the horizontal plate of the bottom frame and the single vertical portion,

wherein the horizontal plate of the bottom frame includes a hole,

wherein the LED PCB further includes a third portion penetrating the hole of the bottom frame, and a fourth portion perpendicular to the third portion,

wherein the first portion of the LED PCB includes a base layer directly contacting the LED housing, an insulating layer directly on the base layer, and a conductive layer on the insulating layer, and the second portion of the LED PCB includes only the base layer, and

wherein the conductive layer includes a plurality of conductive lines electrically connected to the plurality of LEDs.

10. The device according to claim 9 , wherein the fourth portion of the LED PCB is exposed under the horizontal plate of the bottom frame.

11. The device according to claim 9 , wherein the fourth portion of the LED PCB contacts an outer surface of the horizontal plate of the bottom frame.