Tunable lens by spatially varying liquid crystal pretilt angles

We report a method of obtaining controllable spatially varying liquid crystal pretilt angles using a stacked alignment layer. The stacked alignment layer consists of nano-domains of horizontal and vertical alignment materials. The pretilt angle is controlled by varying the domain ratio of the two layers. By using photoalignment material as the top layer, the pretilt angle can be controlled by varying the UV light dosage. A spatially variable UV light beam can be used to control the pretilt angle spatially. An electrically tunable-focus liquid crystal lens is obtained using this method. (C) 2011 American Institute of Physics. [doi:10.1063/1.3567937]