Liquid lens and its applications in optical design

• Main Author: Oikarinen, Kari
• Format: Master Thesis
• Language: English
• Published: University of Oulu 2010
• Subjects: Arctic
• Online Access: https://cris.vtt.fi/en/publications/0bc9345a-9e1e-41d7-9b57-1265b48e6617

The thesis presents a design of a variable focus camera with liquid lens. There are no mechanical moving parts and the only active component is a Varioptic Arctic 320 liquid lens. The liquid lens is based on a phenomenon called electrowetting that can be used to change the contact angle of a conductive liquid with a surface. Inside the liquid lens there are two immiscible liquids that have different indices of refraction: a water solution and an oil. By applying a suitable voltage the interface between the liquids changes shape. Theory behind optical design, physics of electrowetting and modeling this novel component during optical design are discussed. The designed lens system is 24 millimeters long measured from the vertex of the first lens to the surface of the image sensor. It contains no aspherical surfaces. The full field of view of the camera is 40 degrees, its f-number is 2.5 and the effective focal length is approximately 6 millimeters. Nominal performance of the design is presented exhaustively and modulation transfer function measurements from a manufactured prototype are shown. The minimum object distance of the prototype is about two centimeters.