| 摘要 |
An atomic force microscope is offered which is capable of measuring the Q factor of the cantilever (1) quickly. When the Q factor is measured, a switch (14) is closed. Under the initial condition of resonance, a probe (20) is in contact with a specimen (21). The cantilever (1) is in resonance. The output from an error amplifier (13) is null. When the specimen (21) is started to be scanned, the resonance frequency of the cantilever (1) varies according to the physical properties of the specimen portion contacting the probe (20). The phase of the output signal from a low-pass filter (6) is varied. Consequently, the output voltage (V p ) from a phase comparator varies (12). This produces an inverted output voltage (VE) from the error amplifier (13). This output voltage (VE) is added to a preset voltage (V0) and applied to a voltage controlled oscillator (8). The cantilever (1) is vibrated at its resonance frequency at all times. Under this condition, the amplitude of the cantilever (1) is detected by an amplitude detector. Image creation means (19) converts the amplitude of the cantilever into the Q factor, using a previously found calibration curve or sensitivity coefficient. |
