| 摘要 |
Provided is a backlight unit. The backlight unit includes a light source, an optical member configured to uniformly distribute light emitted from the light source, and at least two condensing films configured to condense light from the optical member. Hetero-conic lenses are two-dimensionally arranged on a surface of each of the condensing films, and each of the hetero-conic lenses is formed by combining a first conic lens expressed by Formula (1) below and a second conic lens expressed by Formula (2) below: y = H 1 - x 2 / r 1 1 + 1 - ( 1 + k 1 ) ( 1 / r 1 ) 2 x 2 ( 0≤y≤y 0 ) Formula ( 1 ) y = H 2 - x 2 / r 2 1 + 1 - ( 1 + k 2 ) ( 1 / r 2 ) 2 x 2 + y 0 ( y 0≤y≤H 2 ) Formula ( 2 ) |
