Tunable mirolens array with a large fill-factor: Self-assembly fabrication and electrodrodynamic actuation

• Published in: Sensors and actuators. A. Physical. Vol. 240; pp. 85 - 91
• Main Authors: Li, Rui, Wang, Lanlan, Liu, Hongzhong, Jiang, Weitao, Shi, Yongsheng, Yin, Lei, Zhu, Yongkai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2016
• Subjects: Actuation; Arrays; Decay; Droplets; Electric potential; Electrohydrodynamic; Microcavities; Microcavity array; Miniaturization; Sag heights; Self assembly; Tunable microlens array; Varifocal ability; Tunable microlens array; Electrohydrodynamic; Microcavity array; Self-assembly; Sag heights; Varifocal ability
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2016.01.009

•A high-density (fill-factor 98%) tunable microlens array was constructed.•Diverse substrates (rigid/flexible), without strict geometrical limit, were used.•Sag heights were controlled by pulling velocity and template at room temperature.•TMLA with electrodynamic force showed a four-fold varifocal capability in 50ms. Because a tunable microlens can focus the incident light and shift the focal point, a tunable microlens array (TMLA) with a large fill-factor was fabricated by a self-assembly method. Interestingly, each microcavity was filled completely with a liquid droplet, forming a hemispherical profile by capillary forces. The TMLA had a large fill-factor of up to 98% and various sag heights. Moreover, when a gated square-wave voltage was applied, the focal length of TMLA could be tuned from the initial 540μm to 140μm by electrohydrodynamic force simultaneously; both of the rise and decay time were within 50ms. These results indicate that this novel method can construct TMLA with a large fill-factor, thus providing a new perspective towards portability, miniaturization, and low-cost applications.