Measuring transducer driven by monoaxial piezoelectricity for low-intensity magnetic field

Abstract

The invention provides a measuring transducer driven by monoaxial piezoelectricity for a low-intensity magnetic field, which comprises an insulating base, a GMR (giant magnetoresistive) sensitive element, two same magnetic line of force collectors, a modulating film, a micro cantilever beam and a piezoelectric ceramic sheet. Three pairs of electrodes are plated on the surface of the insulating base; the two magnetic line of force collectors are respectively fixed on the surface of the insulating base at two ends of the GMR sensitive element; the two ends of the GMR sensitive element are respectively positioned in concave grooves of the magnetic line of force collectors; the micro cantilever beam comprises a base and a cantilever; the base is fixed on the insulating base; the base is connected with the cantilever; a free end of the cantilever is provided two aligning holes; the modulating film made of a high-permeability soft magnetic material is prepared between the two aligning holes; a vertical distance between the modulating film and the GMR sensitive element is 8-15 microns; and the piezoelectric ceramic sheet is adhered on the cantilever. The measuring transducer for the low-intensity magnetic field, which is provided by the invention, has a deeper modulation depth, higher resolution power, a simple structure, a simple process and a lower driving voltage.

Description

technical field [0001] The invention relates to the technical field of sensors, in particular to sensors for weak signals, and in particular to a single-axis magnetic sensor for measuring weak magnetic fields. Background technique [0002] Weak magnetic field measurement is widely used in geomagnetic navigation, target detection, geological exploration, biomedicine and other fields. At present, there are many types of sensors used for weak magnetic field measurement, mainly including fluxgate sensors, optical pump magnetic sensors, proton magnetic sensors, optical fiber magnetic sensors, giant magnetoresistive magnetic sensors, and GMR (Giant Magnetoresistive, giant magnetoresistance) Magnetic sensors, etc. Among them, the GMR magnetic sensor is made based on microelectronics technology. Compared with other types of magnetic sensors, it has the characteristics of small size, low power consumption, and easy mass production. [0003] In 1988, the experimental groups led by th...

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Problems solved by technology

[0005] (1) The modulation depth is low, only about 14%, so the magnetic field resolution is low;

[0006] (2) The structure is relatively complex, and the process involves deep reactive ion etching technology and insulating silicon technology, which is time-consuming and labor-intensive, and the cost is high;

[0007] (3) The electrostatic driving voltage required to realize modulation is significantly higher than the power supply voltage of commonly used integrated circuits, reaching more than 50V, which brings inconvenience to actual use

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