Membrane keyboard having key closure retention

A keyboard comprising:

• a first circuit sheet;
• at least one first movable contact element on said first circuit sheet, said first contact element of said first sheet being electroconductive and having magnetic properties;
• a second circuit sheet, said second circuit sheet having at least one second contact element on a first side of said second circuit sheet facing said first circuit sheet, said second contact element being electroconductive and having magnetic properties;
• said first and second contact elements being aligned and normally being electrically disconnected, and being adapted to be brought into electrical contact by movement of said first contact element toward said second contact element;
• electrical circuit means on said first side of said second circuit sheet and defining a coil for the generation of a magnetic field in alignment with said first and second contact elements to retain said first and second contact elements in physical and electrical contact;
• insulation means over said electrical circuit means, said second contact element being supported on said insulation means;
• retention termination means being associated with said circuit means defining a coil for terminating the generation of the magnetic field;
• and
• membrane switch means attached to said second circuit sheet on said second side thereof, said membrance switch means including;
• a first sub-switch sheet adhesively fixed to the second side of said second circuit sheet;
• said first sub-switch sheet having at least one electrically conductive movable contact element thereon;
• a second sub-switch sheet having at least one electrically conductive fixed contact element thereon corresponding to and aligned with the movable contact element on said first sub-switch and with said circuit means defining a coil;
• and
• a spacer sheet separating and adhesively bonded to said first and second sub-switch sheets.