Patent ID: 8684587

Claim:
A backlight unit comprising: a light guide panel; at least two first block partitioning units formed as a groove on a lower surface of the light guide panel, wherein the at least two first partitioning units have a polygonal section that includes one slanted surface and one incident part facing each other; a plurality of light guide blocks formed by partitioning the light guide panel, wherein the light guide blocks are integrated, not separated by at least two first partitioning units, at least two point light sources received in the at least two first block partitioning unit, and constituting one light block corresponding to one of the plurality of light guide blocks, at least one second block partitioning unit that has a hole or groove form, wherein a length of the at least one second block partitioning unit is arranged in a perpendicular direction to a length of the at least two first block partitioning units; and at least one second point light source received in the at least one second block partitioning unit and arranged in the perpendicular direction to the at least two first block partitioning units, wherein the second point light source is turned off during a local dimming driving and turned on except during the local dimming driving, wherein a width of the groove surrounded with the slanted surface and the incident part is formed to be gradually narrower as it goes from the lower surface of the light guide panel to an upper surface of the light guide panel; and wherein lights generated from the point light sources are directly incident to the incident part and are not directly incident to the slanted surface.