Improvement of optical properties and beam steering functions in a liquid crystal microlens with an extra controlling electrode by a planar structure

A new type of liquid-crystal microlens with an extra controlling electrode has been proposed for precise control of the refractive index distribution properties. The extra electrode is fabricated on a substrate outside of the conventional driving electrode in the planar structure. Fundamental optica l properties, that is, the refractive index distribution and focusing prope rties, are investigated by using a cylinder lens which has a striped electr ode structure. Variable focusing and beam steering functions are enhanced b y using the additional electrode with an appropriate driving method. The im provement of the lens property is very effective particularly in the deform ed electrode structure which deviates from the optimum conditions, and this finding facilitates designing of an optical system using the liquid crysta l (LC) microlens for application in various fields. The beam steering range can also be extended without extreme degradation of the lens quality with some assistance from the external. electrode. The extra electrode structure is also introduced in the LC microlens, and the same advantages as with th e cylindrical lens can be obtained.