Patent ID: 7249494

Claim:
A beam tracking system for a scanning-probe type atomic force microscope, comprising: a base to carry a sample to be scanned; a cantilevered probe to scan said sample in order to obtain topographic information representing a surface of said sample; a laser source to generate a laser beam; an optical module to align and introduce said laser beam to said probe; a feedback module, comprising a photo sensing device, to receive a reflected laser beam reflected from said probe and to introduce said reflected laser beam to said photo sensing device; a probe driving device to drive said probe to scan three-dimensionally; an approach mechanism to drive said probe and to adjust the relative position of said probe and said sample; and an information processing module to pick up signals contained in said reflected laser beam as sensed by said photo sensing device and to convert said signals into topographic signals representing the surface of said sample; wherein said optical module comprises an objective lens to focus said laser beam; said probe is located approximately at the focal point of said objective lens; and said laser source, said optical module, said feedback module and said probe are driven by said approach mechanism to move in synchronization.