A drive unit for driving a passive element relative to an active element, wherein the active element comprises a resonator and at least one excitation means for exciting oscillations in the resonator, the resonator comprising at least two arms (21, 22) extending from a connection region of the resonator at the same side of the connection region, the resonator and the arms (21, 22) extending in parallel to a reference plane, each of the arms (21, 22) comprising, at an outer end of the arm, a contact element (31, 32), the contact elements (31, 32) being movable by way of oscillating movements of the arms (21, 22), the passive element being arranged to be driven and moved relative to the active element by way of these oscillating movements; the passive element comprises contact areas (41, 42), each contact area (41, 42) being arranged to be in contact with a respective one of the contact elements (31, 32); wherein a pre-stress element is arranged to exert a relative force between the active element and passive element, whereby each contact area (41, 42) is pressed against the respective contact element (31, 32) with a pre-stress force (Fn) that has a component (Fnz) that is normal to the reference plane, characterised in that the resonator comprises a first surface and an opposed second surface, both parallel to the reference plane, and the first contact area and second contact area are arranged to come into contact only with contact edges (311, 312, 321, 322) of the contact elements (31, 32), the contact edges (311, 312, 321, 322) being located where the contact elements (31, 32), are adjacent to the first and second surface, respectively. a resonator and at least one excitation means for exciting oscillations in the resonator, the resonator comprising at least two arms (21, 22) extending from a connection region of the resonator at the same side of the connection region, the resonator and the arms (21, 22) extending in parallel to a reference plane, each of the arms (21, 22) comprising, at an outer end of the arm, a contact element (31, 32), the contact elements (31, 32) being movable by way of oscillating movements of the arms (21, 22), the passive element being arranged to be driven and moved relative to the active element by way of these oscillating movements; the passive element comprises contact areas (41, 42), each contact area (41, 42) being arranged to be in contact with a respective one of the contact elements (31, 32); wherein a pre-stress element is arranged to exert a relative force between the active element and passive element, whereby each contact area (41, 42) is pressed against the respective contact element (31, 32) with a pre-stress force (Fn) that has a component (Fnz) that is normal to the reference plane, characterised in that the resonator comprises a first surface and an opposed second surface, both parallel to the reference plane, and the first contact area and second contact area are arranged to come into contact only with contact edges (311, 312, 321, 322) of the contact elements (31, 32), the contact edges (311, 312, 321, 322) being located where the contact elements (31, 32), are adjacent to the first and second surface, respectively.