Optical scanner driving apparatus and optical scanner driving method

An optical scanner driving method of driving a optical scanner comprising a driving coil and a moving plate supported with free vibration, said method comprising:

• supplying a driving signal to said driving coil;
• acquiring a first output containing an electromotive force generated in said driving coil by an electromagnetic induction caused by a drive of said driving coil;
• supplying said driving signal to an impedance element corresponding to said driving coil;
• acquiring a second output generated in said impedance element;
• detecting the electromotive force generated in said driving coil on the basis of the first output and the second output;
• and
• controlling the driving signal supplied to said driving coil according to a detected electromotive force.

An optical scanner driving apparatus comprising:

• an optical scanner comprising a moving plate having a reflection plane and comprising a driving coil integrally formed therewith, a support member configured to support said moving plate, an elastic member configured to connect said moving plate and said support member, and a magnetic field generating section arranged in a vicinity of said moving plate;
• a driving circuit configured to supply a driving signal to said driving coil, said moving plate performing a torsional vibration according to said driving signal;
• first output acquiring means for acquiring an output containing an electromotive force generated in said driving coil by an electromagnetic induction on the basis of the magnetic field generated by said magnetic field generating section and the torsional vibration of said driving coil;
• second output acquiring means comprising an impedance element having a corresponding impedance to an impedance of said driving coil, for acquiring an output generated by said impedance element by supplying said driving signal to said impedance element;
• and
• control means for controlling a state of the torsional vibration of said moving plate according to the electromotive force generated in said driving coil on the basis of the output acquired by said first output acquiring means and the output acquired by said second output acquiring means.

An optical scanner driving method of driving an optical scanner comprising a moving plate on which a driving coil is formed, a support member and an elastic member, said method comprising:

• supplying a driving signal to said driving coil;
• acquiring a first output containing an electromotive force generated in said driving coil by an electromagnetic induction caused by a drive of said driving coil;
• supplying said driving signal to an impedance element corresponding to said driving coil;
• acquiring a second output generated in said impedance element;
• detecting the electromotive force generated in said driving coil on the basis of the first output and the second output;
• and
• controlling the driving signal supplied to said driving coil according to a detected electromotive force.

A driving and sensing circuit applied to an electromagnetic driving optical scanner comprising a support member, a moving plate on which a driving coil is formed, an elastic member connecting said support member and said moving plate, and a magnetic field generating section arranged in opposite to said moving plate, said circuit comprising:

• a first acquiring circuit configured to acquire a voltage difference between both ends of said driving coil;
• an impedance element which corresponds to said driving coil;
• a second acquiring circuit configured to acquire a voltage difference between both ends of said impedance element;
• and
• a difference detection circuit configured to obtain a difference between an output from said first acquiring circuit and said second acquiring circuit.

A detection method applied to an electromagnetic driving optical scanner comprising a support member, a moving plate on which a driving coil is formed, an elastic member connecting said support member and said moving plate, and a magnetic field generating section arranged in opposite to said moving plate, said method comprising:

• acquiring a first voltage difference between both ends of said driving coil;
• acquiring a second voltage difference between both ends of said impedance element which corresponds to a resistance of said driving coil;
• and
• obtaining a difference between the first voltage difference and the second voltage difference.