Piezoelectric micro-electro-mechanical actuator device, movable in the plane

A MEMS actuator device comprising:

• a substrate;
• and
• a base unit, the base unit including:
• a base beam element having a first end, a second end, a main extension in an extension plane and a thickness in a thickness direction that is perpendicular to the extension plane and smaller than the main extension;
• a piezoelectric region on or in the base beam element;
• an anchor region fixed with respect to the base beam element and to the substrate;
• and
• a base constraint structure coupled to the second end of the base beam element, the base constraint structure including a base constraint element that is undeformable in the thickness direction and a base hinge structure arranged between the base beam element and the base constraint element, the base constraint structure being configured to allow a movement of the second end of the base beam element in the extension plane and prevent or substantially reduce a deformation of the base beam element in the thickness direction.