Patent ID: 8159638

Claim:
A selective reflection/transmission optical device comprising: a cholesteric liquid crystal (CLC) film that selectively transmits a first light having a first circular polarization and reflects a second light having a second circular polarization, wherein the first and second circular polarizations have opposite directions; a first phase compensation film at the front of the CLC film that generates a phase difference of about λ/4 with respect to an incident light; a second phase compensation film at the rear of the CLC film, for generating a phase difference of λ/4 with respect to an incident light; and a controller for controlling a direction in which an image is displayed, wherein depending on a linear polarization state of the light that is incident into the first phase compensation film, the selective reflection/transmission optical device passes the linearly polarized light that has a polarization axis in a first direction, and reflects all the linearly polarized light that has a polarization axis with an angle of 90° from the first direction, and wherein the CLC film, the first phase compensation film, and the second phase compensation film are disposed in a light path of a dual display liquid crystal display device.