Actuator comprising: a) a support beam b) a first means for placing said support beam in compression without causing flexure of said support beam; c) a first layer of material adhered to a first surface of said support beam and d) a second means for causing movement of said first layer of material to cause a flexure of said layer of material and said support beam, wherein said first layer of material evidences a thermal coefficient of expansion that is different than a thermal coefficient of expansion of said support beam, wherein the actuator is designed to operate at a first working temperature whilst the first layer of material is structurally connected to the support beam at a second temperature wherein the second temperature is higher than the first temperature so as to cause that at the first temperature the said support beam is in compression without causing flexure thereof.