Liquid crystal microlens and improvement of the properties

A graded index type lens can be attained by utilizing the liquid crystal molecular orientation effects in an axially symmetrical electric field which is produced by the circular hole-patterned electrode. The liquid crystal (LC) microlens has a variable focusing property and is easy to make large scale of lens array because of its simple structure. Excellent lens properties can be obtained by optimizing the electrode structure, driving voltage and etc., and the focusing spot size is as small as the diffraction limit. We can expect a new type of lens as an active device for light control by the LC microlens. However, time response of the LC microlens is usually very slow and it has a large aberration caused by the liquid crystal molecular orientation. In this paper, fabrication and fundamental properties of the LC microlens are briefly reviewed, and then the improvement of response and optical properties are discussed. The response and recovery time can be extremely reduced by introducing the polymer stabilization technique using UV curable LC materials. In addition, the aberration can be eliminated by introducing divided electrode structure. The new electrode structure can also provide free space focusing and deflection properties to the LC microlens.