Patent ID: 6748649
Filing Date: 2004-06-15
Classification: H05K,Y10S,Y10T

Abstract:
A method of operating a component holding head including(i) an axially drivable shaft having a nozzle at one end of the shaft for holding a component, (ii) a voice coil motor for driving said shaft in an axial direction in response power supplied to said motor, said motor including one of (a) a magnet fixed to a circumferential surface of said shaft and a coil surrounding said magnet, and (b) a coil fixed o a circumferential surface of said shaft and a magnet surrounding said coil; and (iii) a detecting device, positioned proximate to said shaft, for detecting movement of said shaft in the axial direction, said detecting device including a member to be detected and a sensor for detecting movement of said member, said method comprising: using said sensor to detect movement of said member so as to detect movement of said shaft in the axial direction resulting from said shaft being driven by said motor; and controlling power supplied to said motor in response to the movement of said shaft as detected by said detecting device such that the distance that said shaft is driven by said motor in the axial direction is controlled, wherein said member comprises a magnetic scale and said component holding head further includes a transmission sensor positioned in a non-contact state relative to said magnetic scale, and said method further comprises: using said transmission sensor to detect a presence or absence of blockage of light by a leading end of said magnetic scale such that an origin position of axial movement of said shaft is detected when said magnetic scale axially moves.