An optofluidic tunable Fresnel lens for spatial focal control based on electrowetting-on-dielectric (EWOD)

Autor: Sung-Yong Park, Si Kuan Thio, Carlos Enrico Clement
Rok vydání: 2017
Předmět:
Zdroj: Sensors and Actuators B: Chemical. 240:909-915
ISSN: 0925-4005
DOI: 10.1016/j.snb.2016.08.125
Popis: A Fresnel lens is an optical device that approximates the performance of a conventional bulk lens while using far less lens material for both cost and space effectiveness. However, the use of current solid-type materials fixes the lens optical performance. In this paper, we propose a linear array of liquid prisms to function as a tunable Fresnel lens where each prism is individually controlled by electrowetting-on-dielectric (EWOD) to replace the subsections of a conventional Fresnel lens. Symmetric and asymmetric control of each prism in our Fresnel lens allows spatial focal tuning along the longitudinal (i.e. z-axis) as well as lateral (i.e. x-axis) directions. Analytical studies were conducted to understand the effect of beam steering angle β on the lens performance, particularly for spatial focal control. A 3 × 1 liquid prism array was fabricated to demonstrate the viability of our proposed configuration for a tunable Fresnel lens. By individually controlling each prism using EWOD, we have achieved spatial focal control along the longitudinal (263 mm ≤ flong ≤ ∞) and the lateral (0 ≤ flat ≤ 30 mm) directions. The optofluidic tunable Fresnel lens presented here would show the lens capability for spatial focal control which can be used for potential optical applications such as tracking eye movement for smart displays, or following the motion of the sun for use in compact concentrated photovoltaic (CPV) systems.
Databáze: OpenAIRE
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