128×128 elements liquid crystal cylindrical lens array with electrically tunable focal length

A liquid crystal (LC) cylindrical lens array with electrically tunable focal length is proposed, which is first fabricated. And its optical focusing characteristics are got in tests. The LC cylindrical lens array is driven by applied voltage. It composes of two ITO glasses substrates and LC layer. The top electrode pattern is fabricated by the methods of lithography and hydrochloric acid etching, which has 128×128 elements. Every element is a 60μm×200μm rectangle. The 20μm-thickness-spacer is used to control the LC thickness. When the external electric field is applied, the LC molecules begin to rotate. Then the gradient refractive index forms in the LC cell. The LC cylindrical lens array is a convergent lens array. The parallel white light is used to test its optical characteristics. It comes to a conclusion that the focal length of the LC cylindrical lens array and the external applied voltage has an inverse proportion relationship. The range of the focal length is from 60μm to 450μm, when the applied voltage varies from 1.54 Vrms to 5.0 Vrms. And the response time is up to sub-microsecond. The unique focusing phenomenon of LC cylindrical lens array is that the focusing beams in the top and bottom of every element rectangle are like the image "V".