Touch-sensitive input device with electromagnetic actuator operated at maximum magnetization

A method for controlling a touch-sensitive input device, the method comprising:

• providing a touch-sensitive input device comprising:
• a support;
• an input part comprising a touch-sensitive input surface,
• an elastic device configured to bear the input part at the support along a deflection direction so that the input device is elastically reset and is oscillatively movable;
• an electromagnetic actuator configured to act between the input part and the support so as to produce a deflection of the input part out of a resting position, the deflection comprising at least one effective direction having an effective direction component that is parallel to the deflection direction, the electromagnetic actuator comprising,
• a coil which is configured to define a cavity,
• a ferromagnetic core which is arranged at least in a region in the cavity, the ferromagnetic core being configured to generate a magnetic field defining a pole direction, and
• a ferromagnetic armature which is configured to interact with the magnetic field and which is arranged outside the cavity, and
• control electronics configured to generate an electrical control signal for the ferromagnetic actuator;
• charging the coil of the electromagnetic actuator with the electrical control signal generated by the control electronics after a detection of a contact of the input part and/or after a detection of an actuation of the input part by an actuation force sensor, so as to produce the deflection of the input part out of the resting position and to achieve a maximum deflection of the input part,
• wherein,
• a duration of the electrical control signal is limited so as to provide, after the deflection, a return of the input part to the resting position or an oscillation of the input part around the resting position along the deflection direction, thereby respectively generating a haptic feedback;
• the electrical control signal and the ferromagnetic armature are selected so that, along an imaginary line passing through the ferromagnetic armature in the pole direction, a maximum deflection along a curve of a line is achieved at the latest when a maximum magnetization of the ferromagnetic armature is achieved, and
• the maximum magnetization is at least 90% of a material-specific saturation magnetization.