| 摘要 |
PURPOSE: A back light unit having a light guide without having any optical sheet is provided to improve the luminance of a liquid crystal display employing the back light unit and reduce the number of components of the back light unit to decrease the cost. CONSTITUTION: A pattern that changes a light path is formed on a light guide. A thin film is formed of a material with a refractive index smaller than the refractive index of the light guide on the pattern. A reflection layer is formed of a material having a high reflexibility on the thin film. Lights inputted into the light guide are total-reflected at the boundary of the light guide and the thin film with a low refractive index, transmit the thin film at the pattern region, and then are reflected from the high-reflexibility layer to reach a liquid crystal display panel. |
