A Pico Projection System With Electrically Tunable Optical Zoom Ratio Adopting Two Liquid Crystal Lenses

A pico projection system with electrically tunable optical zoom ratio adopting two liquid crystal (LC) lenses is first demonstrated. The projected image of the system is not only continuously focused, but also zoomed simultaneously by adjusting the focal lengths of LC lenses electrically. The related optical principle is discussed and a liquid-crystal-on-silicon (LCOS)-based pico projection system was used to demonstrate the designed concept. This study opens a new window in realizing pico projectors with electrically tunable optical zooms.