An electrically tunable LCOS pico projector with optical zoom

An electrically tunable zooming LCOS pico projector using composite liquid crystal (LC) lenses is demonstrated. The composite LC lens consists of two built-in sub-lenses: one is an electrically tunable focusing lens controlled by a LC layer and the other is a fixed focused polymeric lens. The zoom ratio of the electrically tunable zooming pico projector can reach 2.5:1 when the screen distance at 20 cm. The tunable focusing ranges are 200 cm to ~10 cm and the response times is around 3.8 sec. The image performance of the electrically tunable focusing LCOS pico projector is also demonstrated.