Provided are a brightness enhancement film including a λ/4 plate, and a reflection polarizer, in which the reflection polarizer includes at least two light reflection layers formed by immobilizing a cholesteric liquid crystalline phase, one light reflection layer of the reflection layers is a layer formed of a polymerizable liquid crystal composition containing a rod-like liquid crystal compound, and the other light reflection layer is a layer formed of a polymerizable liquid crystal composition containing a disk-like liquid crystal compound, and an optical sheet member including the brightness enhancement film, and a liquid crystal display device including the optical sheet member. The brightness enhancement film of the present invention has high brightness and is able to suppress an oblique change in the shade at the time of being incorporated in a liquid crystal display device.
本发明提供了一种亮度增强膜,包括λ/4板和反射偏振片,其中反射偏振片包括至少两个通过固定胆甾
液晶相形成的光反射层,反射层中的一个光反射层是由含有
棒状
液晶化合物的可聚合
液晶组合物形成的层,另一个光反射层是由含有盘状
液晶化合物的可聚合
液晶组合物形成的层,以及包括该亮度增强膜的光学
薄片部件和包括该光学
薄片部件的
液晶显示装置。本发明的亮度增强膜具有高亮度,并且在装入
液晶显示装置时能够抑制阴影的斜向变化。