Proximity sensor and rotational operation detecting device

A rotational operation detecting device having a rotation detecting section for detecting a rotational operation of a rotationally-operable knob about an axis, the rotational operation detecting device comprising:

• a first capacitor arranged inside the knob at a distal end of the axis in a direction along the axis;
• a second capacitor arranged inside the knob at a proximal end of the axis in a direction along the axis;
• a detection section including a first detection unit for detecting approach of an object based on variations in capacitance of the first capacitor and a second detection unit for detecting approach of the object based on variations in capacitance of the second capacitor, wherein relative detection sensitivities of the first and second detection units are such that a detection level detected by the first detection unit is greater than a detection level detected by the second detection unit when the object approaches from a first direction along the axis, and that the detection level detected by the second detection unit is greater than the detection level detected by the first detection unit when the object approaches from a second direction perpendicular to the first direction;
• a proximity position determining section for determining the approaching direction of the object based on the detection level of the first detection unit and the detection level of the second detection unit;
• and
• an output control section for allowing output of signals from the detection section only when a rotational operation of the knob is detected in the detection section when the proximity position determining section detects approach of the object from the second direction.