Abstract: An optical device includes a substrate, a sensor layer, a light-filtering layer, and a control module. The sensor layer is disposed on the substrate and generates a pre-scan image. The light-filtering layer is disposed over the sensor layer, wherein the light-filtering layer allows or blocks external light from reaching the sensor layer. The control module is coupled to the sensor layer and the light-filtering layer, wherein the control module controls the light-filtering layer according to the pre-scan image to selectively allow or block external light.

Abstract: Disclosed herein is a display device switchable between a mirror mode and a display mode. The display device includes a display panel, a polarizing element and a reflective polarizer. The display panel has a light-emitting surface for emitting a polarized light. The polarizing element has an absorption axis, and is disposed on a side adjacent to the light-emitting surface. The polarizing element is switchable between a polarizing mode and a non-polarizing mode. When the polarizing element is operated in the polarizing mode, the polarizing element absorbs a polarized light in the polarization direction parallel with the absorption axis. When the polarizing element is operated in the non-polarizing mode, the polarizing element allows the polarized light emitted from the display panel to pass there through. The reflective polarizer is disposed between the display panel and the polarizing element.