Novel optical accelerometer based on Fresnel diffractive micro lens

This paper presents an innovative optical accelerometer based on an integration of a Fresnel diffractive micro lens with a reflecting membrane. The reflecting membrane mounted on an inertial mass is placed parallel behind the diffractive micro lens. The light intensity at the conjugate position of an applied monochromatic point source is highly sensitive to the displacement of the membrane. The working principle is specifically discussed. In addition, this sensor makes use of a quad beam structure to allow the flat displacement of the inertial mass. Mechanical simulations using finite element method show the designed structure has a wide range of operation. A prototype accelerometer has been successfully developed. Dynamic tests indicate that the accelerometer has promising performance. This accelerometer can be fabricated using microelectromechanical systems (MEMS) technology, with relatively few process steps, so it is suitable for batch production. By optimizing structural designs, it can be a competitive candidate for a number of application fields ranging from vibration monitoring to inertial navigation.