| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical unit which has remarkably improved efficiency of use of light and consequently provides remarkably improved luminance and is suitable for a direct liquid crystal display module or the like and to provide a back light unit. <P>SOLUTION: The optical unit is a rectangular layered structure provided with a reflection polarization plate, an optical sheet laminated on the rear surface side of the reflection polarization plate and a transparent medium layer filled between the reflection polarization plate and the optical sheet. The optical sheet has a resin made base material film having optical anisotropy and the absolute value of the angle of the base material film in the crystal axis direction based on the transmission axis direction of reflection polarization plate is ≥π/8 and ≤3π/8. It is preferable that the retardation of the base material film is ≥70 nm and ≤320 nm and the optical sheet has an optical layer layered on one surface of the base material film. The liquid crystal module has a liquid crystal element, the optical unit, and the back light of a direct type or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT |
