1. US20060078692 - Optical laminate polarization light source device and liquid crystal display unit

An optical laminate comprising a cholesteric liquid crystal layer and a ¼ wavelength plate laminated one upon another, characterized in that the ¼ wavelength plate comprises at least one layer (layer A) consisting of a material having a positive intrinsic birefringence least one layer (layer B) consisting of a material having a negative intrinsic double refraction value, the orientations of molecular chains in the layer A and the layer B are equal to each other, and a variation in thickness of the ¼ wavelength plate is below 5%; a polarization light source device provided with this optical laminate; and a liquid crystal display unit provided with this polarization light source device. The optical laminate which delivers an excellent brightness improving effect, is free from a variation in in-plane brightness, and ensures a long-term, stable brightness improving effect; and the polarized light source device and the liquid crystal display unit provided with this optical laminate are provided.