Method for controlling a piezoelectric device having a piezoelectric element mounted on a substrate

1. A method for controlling a piezoelectric device comprising a piezoelectric element fixed on a substrate, with the substrate and the piezoelectric element being made of materials having different coefficients of thermal expansion, with the method comprising the step of subjecting the piezoelectric element to a predetermined electric voltage to cause a predetermined set deformation of the piezoelectric element, wherein the predetermined electric voltage comprises a compensation portion determined according to ambient temperature to cancel a stress generated on the piezoelectric element due to a differential thermal expansion between the piezoelectric element and the substrate.

2. The method according to claim 1 , wherein the ambient temperature is periodically measured and the compensation portion is periodically determined.

3. The method according to claim 1 , wherein the compensation portion is determined using a table relating ambient temperature values with compensation portion values.

4. A piezoelectric device comprising a piezoelectric element fixed on a substrate, with the substrate and the piezoelectric element being made of materials having different coefficients of thermal expansion, with the device comprising a control unit which is connected to an energizing circuit of the piezoelectric element and which is so arranged as to implement the method according to claim 1 .