OPERATION INPUT DEVICE

PROBLEM TO BE SOLVED: To provide an operation input device enabling stable detection by obtaining a large variation of capacitance while increasing the resolution especially of rotation position detection. SOLUTION: A rotor 20 connected to a knob 80 is faced to a plurality of electrode groups R arranged like a ring on an electrode base 10 via a coil spring 75 and knob holder 70. The electrode group has a conical spring 3 as a movable electrode, and a pressing terminal 5 extended from a rubber cup 4. When the knob is rotated, a pressing section K of the rotor presses down the pressing terminal on its slope, compresses the conical spring via the rubber cup, and varies the capacitances of the electrode groups. The number of pressing sections is set more than that of the electrode groups, the rotation position of the knob can be detected at a high resolution because the capacitances of the electrode groups sequentially vary in the unit of knob rotation angle smaller than the arrangement interval of the electrode groups, the variation width of the capacitance is large because the electrode groups use the conical spring as a movable electrode, and the detection stability is high. COPYRIGHT: (C)2007,JPO&INPIT