Patent ID: 7651241

Claim:
A direct type backlight unit comprising; a plurality of lamps arranged in a plane with respect to a display area; a diffusion sheet and a diffuser sequentially arranged above the plurality of lamps; a main dot pattern portion formed on at least one of the diffuser and the diffusion sheet to face the plurality of lamps, and having first dot patterns dispersing the light by being formed along the long direction at the center of each lamp; and a sub dot pattern portion formed on at least one of the diffuser and the diffusion sheet to face the plurality of lamps, and having second dot patterns condensing the light by being formed in the boundary between the lamps, wherein the second dot patterns have a pattern size and pattern distance smaller than a pattern size and pattern distance of the first dot patterns, and wherein the first and second dot patterns are formed by a mixture of a transparent ink having property transmitting light and a white ink having property reflecting light, and the mixture ratio between the transparent ink and the white ink forming the first and second dot patterns is maintained in the range of 2:1 to 3:1.