2004 年 70 巻 689 号 p. 168-174
In atomic force microscopy (AFM), the deflection of the micro-machined cantilever equipped with a sensor tip measures an interactive force between a tip and a sample. Quantitative applications, including evaluation of elasticity and adhesion of sample surface in nano-scale, require AFM cantilevers to be measured accurately for the spring constants. Direct methods of determining spring constants, where the deflection of a cantilever is measured as a function of applied load, are reliable rather than indirect methods based on analysis of cantilever vibrations. This study proposes a novel direct method having the advantage of non-contact loading, where micro jet of inert gas from a micropipette produces a well-defined fluid force ranging from lnN to 10 pN. Combing the loading device with a laser interferometer for measuring sub-micro deflection of cantilevers makes possible the determination of spring constants with uncertainty of ±8%.