Recently, a fast liquid crystal (LC) lens with stacked structure of thin LC layers has been proposed [1]. The response time can be controlled within one second and the decay time becomes only 150 ms. The lens power can be maintained due to the stacked LC layers even though thin LC layers are used. Here we report our research on the transient properties of the LC lens. Method of improvement of the transient properties is proposed. By using two-voltage driving approach [2], the focus range is expanded by driving the LC cell working as not only a positive lens but also a negative lens [3]. The transient behaviors of the LC cell switching between positive and negative lens are studied, and it is found that the LC lens has a wide focus range, and the switching between positive and negative lens becomes very fast.

[1] B. Wang, M. Ye, and S. Sato, Opt. Commun. 250 (2005) 266. [2] M. Ye, B. Wang and S. Sato, Appl. Opt. 43 (2004) 6407. [3] B. Wang, M. Ye, and S. Sato, IEEE Photon. Technol. Lett. 18 (2006) 79.