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Fabrication of tapered SU-8 structure and effect of sidewall angle for a variable focus microlens using EWOD

Chang, Yuan-Jen and Mohseni, Kamran and Bright, Victor M. (2007) Fabrication of tapered SU-8 structure and effect of sidewall angle for a variable focus microlens using EWOD. Sensors and Actuators A: Physical, 136 (2). 546 - 553. (In Press)

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Official URL: http://www.sciencedirect.com/science/article/B6THG...

Abstract

Electrowetting on dielectric (EWOD) is a promising technology for variable focus liquid microlens. When an electrical field is applied across a liquid droplet and a dielectric layer, the contact angle of the liquid can be tuned with different applied voltages. Therefore, the focal length of a microlens would vary by simply applying an electrical field without any moving mechanical components. In this paper, SU-8 is employed as dielectric layer and structural material in the design of a variable focus liquid microlens using EWOD. A tapered SU-8 structure is created by UV overexposure to confine the droplet and provide the droplet-centering mechanism. The angle of the sidewall is controlled by the width of the exposed area. Contact angle variation of water droplets on SU-8 is measured and favorably compared with the Lippmann–Young equation. The working microlens is demonstrated using images of numbers and laser beam focusing.

Item Type:Article
Additional Information:Micromechanics Section of Sensors and Actuators, Based on Contributions revised from the Technical Digest of the 2006 Solid-State Sensor, Actuator and Microsytems Workshop
Uncontrolled Keywords:Electrowetting; SU-8; Microlens
Subjects:Analytical Science > Nanotechnology for sensing and actuating
ID Code:4833
Deposited By:SPI
Deposited On:28 Apr 2009 10:41
Last Modified:28 Apr 2009 10:41

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