Design of thin-film AlN actuators for 4-inch transparent plates for haptic applications

Numerous applications require tactile interfaces today. In particular, many customers´ applications such as Smartphone, tablet PC or touch pad can be concerned by high performances, low voltage haptic interfaces which allow the user to interact with its environment by the sense of touch. This technology is already used but with limitations such as high power consumption and limited feedback effect (simple vibration). We chose to work on the squeeze-film effect. It consists in changing the friction between the finger and a plate resonator. It provides high granularity level of haptic sensation. This paper deals with the design of high performances actuators in order to promote the squeeze-film effect on a 4-inch plate (diagonal of the plate). Using predictive models, we select the best design, able to generate the highest substrate displacement amplitude as possible. We built demonstrators using a generic technology based on thin-film AlN actuators. Electromechanical characterization is ongoing before the integration of the thin-film actuator plate in a haptic demonstrator in a close future.