US Patent 10391237 Actuator and actuation method

An actuator comprises: a cavity containing a working medium (B) that reversibly expands as it undergoes a phase change from a solid to a liquid state; a diaphragm disposed adjacent the cavity such that expansion and contraction of the expandable working medium (B) causes the diaphragm to deflect, and a semiconductor element (A) disposed in the cavity. The semiconductor element (A) is operable in a first mode to heat the working medium (B) to cause it to undergo the phase change into the liquid state, and is operable in a second mode to measure the temperature at the semiconductor element (A). The corresponding actuation method is also disclosed.