Parts mounting inspection method

An inspection method for inspecting the existence or non-existence of parts mounted on a circuit board, said method comprising the steps of:

• providing a light source for irradiating the parts with a laser beam, an optical system path for irradiating the parts with the laser beam from the light source, a signal output path for outputting a reference signal by the laser beam from the light source, and processing means for processing a signal from each of the optical system path and the signal output path;
• holding the parts in a predetermined position to detect a reference signal by irradiating the parts with the laser beam;
• holding the parts in a first position and irradiating the optical system path and the signal output path with the laser beam to detect a signal from each path, and outputting by the processing means a phase difference signal, corresponding to the first position, of output from each path;
• and
• determining the existence or non-existence of the parts on the basis of the reference signal and the phase difference signal.

An inspection method for inspecting a height posture of parts mounted on a circuit board, said method comprising the steps of:

• providing moving means for moving a stage holding the circuit board, a light source for irradiating the parts with a laser beam, an optical system path for irradiating the parts with the laser beam from the light source, a signal output path for outputting a reference signal by the laser beam from the light source, and processing means for processing a signal from each of the optical system path and the signal output path;
• obtaining reference signals A' and B' at first and second positions, respectively, of the parts;
• holding the parts in the first position and irradiating the optical system path and the signal output path with the laser beam to detect a signal from each path, and outputting from the processing means a phase difference signal, corresponding to the first position, of output from each path to detect a signal representing the height of the parts in the first position;
• moving the parts to the second position by the moving means;
• holding the parts in the second position and irradiating the optical system path and the signal output path with the laser beam to detect a signal from each path, and outputting from the processing means a phase difference signal, corresponding to the second position, of output from each path to detect a signal representing the height of the parts in the second position;
• and
• determining an inclined posture of the parts by comparison of the reference signals A' and B' and the signals representing the height of the parts in the first and second positions.