Mounting device and method for detecting displacement

A mounting device, comprising:

• a bonding head, having a cylindrical side surface;
• a support member, supporting the bonding head so as to be capable of advancing and retreating in an axial direction along a central axis of the cylindrical side surface and capable of rotating around the central axis;
• a first actuator, causing the bonding head to advance and retreat in the axial direction;
• a second actuator, having an output shaft that does not coincide with the central axis and causing the bonding head to rotate around the axis;
• a first scale, provided on the cylindrical side surface for detecting displacement of the bonding head in the axial direction;
• a second scale, provided on the cylindrical side surface for detecting displacement of the bonding head around the axis;
• a first sensor head, reading the first scale and outputting a first detection signal corresponding to displacement of the bonding head in the axial direction;
• and
• a second sensor head supported by the support member, reading the second scale and outputting a second detection signal corresponding to displacement of the bonding head around the axis.