Patent ID: 7455425

Claim:
A backlight unit for illuminating an object to be illuminated provided with at least two directional brightness gradients using a plurality of light sources disposed directly below the object to be illuminated, wherein the backlight unit has a reflection portion for causing the light from the plurality of light sources to exit toward a certain direction, wherein the reflection portion comprises at least a first and a second reflection layers having a predetermined level of light reflectance and transmittance, wherein the reflection portion consists of a first region with the first and second reflection layers being overlapped in the incident direction of light located at a position equivalent to the central portion of the object to be illuminated and a second region consisting of the first reflection layer only, and wherein the brightness gradient is formed in the horizontal and vertical directions of the object to be illuminated by controlling reflectance of the reflection portion using the first region with relatively higher reflectance and the second region with lower reflectance than the first region.