| 摘要 |
PURPOSE: A light guide panel for backlight removing all sheets using an optical filter layer forming technique is provided to form a thin film coating layer of a material having a lower refractive index on an LCD opposite surface, to make light having an angle more than a critical angle selectively incident on the coating layer, and to form a reflective layer on the thin film layer, so that the light can be vertical toward an LCD. CONSTITUTION: On an LCD opposite surface of a light guide panel(2), an optical filter layer(3) is made, to arrange incident lights to have specific directional properties. A reflective layer is made on the optical filter layer(3), so that the arranged lights can be toward an LCD. An interface(1) is a boundary layer of a PMMA(Polymethylmethacrylate) and the air. An interface(2) is a boundary layer between the PMMA and MgF2. Light velocity incident on the light guide panel(2) from a light source(1) totally reflects before reaching a critical angle from the interface(1) or the interface(2). The interface(1) and the interface(2) are not in parallel, and have an angle difference as "b". Whenever light reflecting on the light guide panel(2) reflects on the two interfaces(1, 2) one time, a reflecting angle for the interfaces(1, 2) is reduced as much as "b". Lights incoming to an MgF2 layer have bigger angles than the critical angle. Lights that do not reach the critical angle enter the MgF2 layer after reaching the critical angle by a further proceeding. |
