High-sensitivity MEMS photoelectric galvanometer, making and detecting method thereof

Abstract

The invention relates to an optical electric galvanometer, based on Micro-Electronic Mechanic System (MEMS). It is characterized in that: it use micro mechanical technique to prepare the screw coil MEMS torsion micro lens; it can avoid amplify circuit, that directly inputting the tested current or low-frequency weak current into driving coil, to be arranged in the strong magnetic field generated by external permanent magnet; the driving coil drives the micro lens to deflect from original position by the torque generated by Lorentz force; it uses dual optical fiber collimator to test the characters that sensitive to the angle; according to the relationship between the optical signal loss and the torsion angle, via optical electric conversion and signal processing, attaining the current value. The invention can avoid amplify circuit at the input end, to attain amp level and pF level, to overcome the defects of noise disturb and excursion when amplifying the micro weak current signal. And it can realize the optical electric separation at input and output ends synchronously, with small volume, simple structure, lower cost and better anti-vibration ability.

Description

technical field [0001] The invention relates to a high-sensitivity MEMS photoelectric galvanometer and its production and detection method, which is a detection ampere to picoampere level used in the technical fields of measurement and testing, electric power, biology, semiconductors, and chemical analysis. current photogalvanometer. Background technique [0002] The monitoring and detection technology of weak current is more and more applied in many fields such as weak signal precision measurement, biological current detection, semiconductor, electric power, chemical analysis, industrial production and so on. The detection and control of weak currents plays an important role in the field of metrology, and the sensitivity and accuracy of weak current detection equipment have also received more attention; bioelectrodes are important tools for studying life phenomena at the molecular level, most of which are current Output type, the current signal is usually interfered by a v...

AI Technical Summary

Problems solved by technology

Early micro-current amplifiers made of carefully selected vacuum tubes can achieve high sensitivity, but vacuum tubes have fatal shortcomings of large volume and serious temperature drift

Nowadays, micro-current amplifiers are generally made of integrated operational amplifier chips, but there are difficulties in meeting the requirements of low noise interference, low drift, and fast response.

Operational amplifiers also have problems such as offset voltage, offset current, bias current, and temperature drift. After the continuous accumulation of integral capacitance, the phenomenon of so-called "integral drift" appears, which causes great errors in measurement.

[0004] Another method for detecting weak currents does not require an amplifier [Xiang Xiaomin, Zeng Weilu, Gao Xuejun. A new magnetic modulation DC current measurement method [J]. Journal of Huazhong University of Science and Technology, 1998, 26(12): 64-67. ], its principle is mostly to measure the change of the magnetic field generated by the current, such as the Hall sensor, etc., but its detection sensitivity is relatively low, and it is difficult to reach below the milliampere level

At present, it is difficult to measure the non-contact DC micro current below 1mA. If the Hall element is used, even if the magnetic focusing method is used, the minimum current is about 20mA or more to respond.

The traditional comparator has high precision in measuring current, but it uses the principle of closed-loop measurement, and the circuit structure is complicated. poor stability

The low-temperature superconducting comparator with superconducting quantum interference device can achieve high measurement accuracy (10 -12 A), but this instrument needs to work at low temperature, and reading data at room temperature requires sophisticated temperature control and compensation devices, and the entire set of instruments is expensive

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