Micro- cantilever beam sensing sensitivity control system

Abstract

A manipulation system for a microcantilever with improved sensing sensitivity comprises a central control unit, a numerically controlled vibrator, a sensor driver and a sensor deformation detector, a device for detecting, converting, amplifying and filtering a sensor deformation signal, a phase shifter, an vibration amplitude and phase signal converter, a dynamic vibration amplitude and phase signal compensator, a microcantilever sensing sensitivity controller, and a multi-channel high-precision analog-to-digital converter. The output signal of sensor vibration amplitude is subjected to proper phase shift and vibration amplitude amplification and added with the original excitation signal of the sensor to obtain a new vibration source signal of the sensor. The inventive system can detect the vibration amplitude and phase changes caused by external physical change exerted on the microcantilever with high precision, convert the change to corresponding voltage change, and feed in the multi-channel high-precision analog-to-digital converter, so that the central control unit can perform timely observation, analysis and monitoring.

Description

technical field [0001] The present invention relates to an ultra-precise and precise signal measurement system, which is widely used in nanoscale measurement and detection instruments, such as scanning probe microscopes, atomic force microscopes, scanning capacitance microscopes, scanning resistance microscopes, and precision temperature and humidity Measuring devices, etc., especially a micro-cantilever sensing sensitivity control system Background technique [0002] The previous atomic force microscope technology is only applicable to the operation mode in the air, such as the earlier Taiwan Patent Publication No. 00103159, which describes the atomic force microscope and the method of displaying the surface with atomic resolution, for the use in deep water and vacuum The problems that may arise from the environment and the corresponding solutions are not mentioned in the patent; in addition, the previous technologies of atomic force microscopes, such as the technologies r...

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Problems solved by technology

[0002]The previous AFM technology is only applicable to the operation mode in the air, such as the earlier Taiwan Patent Publication No. 00103159, which stated that the AFM and the atomic resolution The method of displaying the surface is not mentioned in the patent for the possible problems and corresponding solutions in the use environment in deep water and vacuum; in addition, the previous technology of atomic force microscope, such as the patent announcement of Taiwan, China The technologies described in No. 00435701 and Announcement No. D103627 are only limited to the nano-microscopic technology in the air, and do not describe the method of use in deep water or in vacuum as mentioned in the present invention

[0003] In addition, the previous technology, as recorded in Taiwan Patent Publication No. 580573, requires two direct digital synthesizers to generate two sine wave signals in its phase difference detection device , the cost is significantly higher, which is different from the present invention which only uses a central control unit to control a numerically controlled oscillator to generate a sine wave of a specific frequency required for work

Secondly, the Taiwan Patent Announcement No. 580573 case uses two direct digital synthesizers to generate two sine wave signals, one of which is used as the actuation signal of the sensor, and the other is used as the reference measurement signal. When the measurement system works, the above two The signal must work at the same frequency, but in fact, the Taiwan Patent Announcement No. 580573 cannot ideally generate a signal of the same frequency as expected in the patent, so the measurement method described in the patent will be due to The difference in frequency between the reference signal and the measurement signal causes serious measurement errors and introduces unavoidable measurement noise, which seriously affects the measurement resolution

Furthermore, the system architecture of Taiwan Patent Announcement No. 580573 does not have the phase shifter and the two-stage signal amplification and clamping components proposed in the present invention, so the method proposed in this patent cannot realize the phase detection on the one hand. The measuring mechanism is shifted to a more sensitive phase angle, so the phase conversion sensitivity of this patent is poor. On the other hand, the method contained in this patent also has difficulty in measuring weak signals.

In addition, the signal output by the phase detector described in this patent still needs to pass through the counter, and then be processed by the microprocessor before the phase difference signal can be obtained. The counter, which is an analog voltage signal that is completely positively correlated with the phase signal, has a significant difference

China Taiwan Patent Announcement No. 580573 patent does not have the band-pass filter proposed by the present invention, so as to filter out the square wave amplitude component in the phase signal, so the phase signal of the invention will still be affected by the amplitude of the signal to be measured

Another difference from the technology contained in the present invention is that this invention can not only measure the precise phase change, but also detect the slight amplitude change of the sensor synchronously. This technology is disclosed in Taiwan Patent Publication No. 580573 It is not mentioned, and finally, the Taiwan Patent Publication No. 580573 patent does not have the dynamic drive signal controller and the dynamic signal compensator described in the present invention, so the method proposed in this patent cannot respond to different sensors actuated Compensation of dynamic signals between piezoelectric materials and measurements of different physical quantities

[0004]In summary, if the method mentioned in the above patent is operated in aqueous solution or in vacuum, the sensitivity of the sensor will deteriorate, and it will not be able to achieve nanoscale analysis Spend

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