Slim type backlight unit

Abstract

A backlight unit of the invention is reduced in thickness, weight and manufacturing costs but improved in heat releasing efficiency. In the backlight unit, a flexible printed circuit board has at least one through hole perforated therein. An LED package is disposed on a top portion of the flexible printed circuit board corresponding to the through hole. The backlight unit of the invention employs the flexible printed circuit board in place of a metal printed circuit board as a means to conduct current to the LED package. This produces a slimmer and lighter backlight unit and also saves manufacturing costs. In addition, the LED package is directly bonded onto a bottom plate by a heat conducting adhesive, thereby ensuring heat generated from the LED package to be released more quickly.

1 . A backlight unit comprising:
 a flexible printed circuit board having at least one through hole perforated therein; and   an LED package disposed on a top portion of the flexible printed circuit board corresponding to the through hole.   
     
     
         2 . The backlight unit according to  claim 1 , wherein the flexible printed circuit board has an electrically-conducting pattern formed on a top surface thereof,
 wherein the LED package further comprises a lead frame connected to the pattern to receive current.   
     
     
         3 . The backlight unit according to  claim 1 , wherein the flexible printed circuit board is made of polyimide. 
     
     
         4 . The backlight unit according to  claim 1 , wherein the flexible printed circuit board further comprises a reinforcement plate provided on a top surface or an underside surface thereof. 
     
     
         5 . The backlight unit according to  claim 1 , further comprising:
 a bottom plate where the flexible printed circuit board is mounted; and   a heat conducting adhesive formed in the through hole to connect an underside surface of the LED package with a top surface of the bottom plate.   
     
     
         6 . The backlight unit according to  claim 5 , wherein the LED package is configured such that the heat conducting adhesive is adhered in an area where a heat sink is disposed. 
     
     
         7 . The backlight unit according to  claim 5 , wherein the bottom plate is made of a metallic material.