High-contrast Artificial Eyelid for Protection of Optical Sensors
The fabrication, testing and performance of a new device for the protection of optical sensors will be described. The device consists of a transparent substrate, a transparent conducting electrode, insulating polymers, and a reflective top electrode layer. Using standard integrated circuit fabrication techniques, arrays of apertures can be created with sizes ranging from micrometers to millimeters. A stress gradient resulting from different thermal coefficients of expansion between the top polymer layer and the reflective metal electrode, rolls back the composite thin film structure from the aperture area once a release layer is chemically etched away, forming a tightly curled film at one side of the aperture - the open condition. The application of a voltage between the transparent conducting and reflective metal electrodes creates an electrostatic force which unrolls the curled film, closing the artificial eyelid. Fabricated devices have been completed on glass substrates with indium tin oxide electrodes. The curled films have diameters of less than 100 micrometers with the arrays having mechanical transparencies of over 80%. Greater transparencies are possible with optimized designs. The electrical and optical results from the testing of the artificial eyelid will be discussed including the optimization of the design and fabrication for applications in systems that extend into the IR spectrum. A primary area of investigation is the choice of the transparent conducting electrode.
M. Davidson et al., "High-contrast Artificial Eyelid for Protection of Optical Sensors," Smart Structures and Materials 2001: Electroactive Polymer Actuators and Devices, Proceedings SPIE, SPIE -- The International Society for Optical Engineering, Mar 2001.
The definitive version is available at http://dx.doi.org/10.1117/12.432674
Materials Science and Engineering
Keywords and Phrases
Artificial Eyelid; Optical Sensors; Protection
Article - Conference proceedings
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