Cantilever device and cantilever controlling method

A cantilever device used for an atomic force microscope which measures a surface geometry of a measuring object, comprising:

• a cantilever equipped with a probe at a tip and capable of vibrating;
• a vibration source which realizes the cantilever to vibrate in the self-excited mode;
• a detection mechanism which detects a deflection or a displacement of the cantilever;
• and
• a control unit which performs a feedback control of the vibration source based on the deflection the displacement of the cantilever, wherein
• a feedback control signal VC generated by the control unit is given by Equation (3) below:
• [Formula 3]
• Vc=−Kin˜wdt|S=XS+Knon∫wm+1dt∫S=XS (3)
• where Klin is a linear feedback gain which is positive, Knon is a nonlinear feedback gain which is positive, w is the deflection or the displacement of the cantilever, XS is a sensing point for the cantilever, and m is an even number equal to or larger than 2.

A cantilever controlling method for a cantilever device used for an atomic force microscope which measures a surface geometry of a measuring object, in which the cantilever device comprising a cantilever equipped with a probe at a tip and capable of vibrating, a vibration source which realizes the cantilever to vibrate in the self-excited mode, a detection mechanism which detects a deflection angle of the cantilever, and a control unit which performs a feedback control of the vibration source based on the deflection angle of the cantilever, wherein

• the control unit controls the vibration source based on a feedback control signal VC given by Equation (5) below:
• [
• Formula
• 
• 
• 5
• ]
• V
• c
• =
• -
• K
• lin
• 
• ∫
• ∂
• w
• ∂
• s
• 
• 
• t
• 
• 
• s
• =
• x
• s
• 
• +
• K
• non
• 
• ∫
• (
• ∂
• w
• ∂
• s
• )
• m
• +
• 1
• 
• 
• t
• 
• 
• s
• =
• x
• s
• (
• 5
• )
• where Klin is a linear feedback gain which is positive, Knon is a nonlinear feedback gain which is positive, ∂w/∂s is the deflection angle of the cantilever, XS is a sensing point for the cantilever, and m is an even number equal to or larger than 2.

A cantilever controlling method for a cantilever device used for an atomic force microscope which measures a surface geometry of a measuring object, in which the cantilever device comprising a cantilever equipped with a probe at a tip and capable of vibrating, a vibration source which realizes the cantilever to vibrate in the self-excited mode, a detection mechanism which detects a deflection or a displacement of the cantilever, and a control unit which performs a feedback control of the vibration source based on the deflection or displacement of the cantilever, wherein

• the control unit controls the vibration source based on a feedback control signal VC given by Equation (7) below:
• [Formula 7]
• Vo=−Klin∫wdt|S=XS+Knon∫wm+1dt|S=XS (7)
• where Klin is a linear feedback gain which is positive, Knon is a nonlinear feedback gain which is positive, w is the deflection or the displacement of the cantilever, XS is a sensing point for the cantilever, and m is an even number equal to or larger than 2.