Haptic signalizing device

A haptic signalizing device, comprising:

• a number of piezoelectric elements arranged below a device surface such that mechanical deformations caused by a converse piezoelectric effect in at least one piezoelectric element make the device surface to move such that the device surface follows the piezoelectric element;
• and
• a driving circuit configured to cause the converse piezoelectric effect on the at least one piezoelectric element by generating an alternating electric field over the piezoelectric element in a bipolar fashion, that is, consecutively in both the same and an opposite direction with a respect to the polarization of the piezoelectric element, to make the piezoelectric element to move beyond its initial position consecutively in both directions;
• wherein a depolarization limit is determined by the haptic signalizing device by using the piezoelectric element to detect when an electrical field, which is in the opposite direction with a respect to the polarization of the piezoelectric element, starts to depolarize the piezoelectric element;
• wherein the driving circuit is configured to cause the converse piezoelectric effect on the at least one piezoelectric element by generating the alternating electric field over the piezoelectric element so that a magnitude of a component of the alternating electric field which is driven to the opposite direction with the respect to the polarization, is based on the determined depolarization limit;
• and
• wherein the driving circuit is configured to cause the converse piezoelectric effect on the piezoelectric element by generating the alternating electric field over the at least one piezoelectric element so that a magnitude of the component of the alternating electric field, which is driven to the same direction with the respect to the polarization, is based on a level where a short circuiting starts to occur at the piezoelectric element.