Fully flexible hot film sensor array for underwater applications

Flexible hot film sensor array was developed for underwater applications. To minimize conductive heat loss to substrate, heighten sensitivity and shorten response time nickel thin film resistors are fabricated on polyimide substrate. Fully flexible structure and very low thickness of the sensing belt enable it possible to be taped on highly curved surfaces to measure fluid parameters with minimal invasion. Polymer compatible micromachining technologies with further consideration of waterproof coating were developed. High temperature coefficient of resistance (TCR) and low time constant of sensor were obtained. A hydrodynamic experimental setup was established, and a demonstration indicated flow velocity can be measured with the sensor.