Miniature viscometer based on self-mixing interferometer

This work addresses development of a miniature viscometer. The miniature viscometer is based on a self-mixing interferometer. The viscosity is determined from mechanical resistance that is measured by a vibrating disc immersed in a liquid. Some MEMS viscometers are based on a similar principle. The main innovative advantage of the proposed viscometer is the use of self-mixing interferometer technology for accurate sensing of the position of the vibrating disc. The vibrating disc is mechanically connected to an electromagnetic microactuator. The microactuator excites the vibrating disc by a sinusoidal waveform of constant force. The vibrating disk is immersed in the measured liquid. The mechanical resistance caused by the viscosity of the fluid dampens the amplitude of the disk's vibrations. Depending on the magnitude of the vibration amplitude, the viscosity value of the measured liquid can be determined.