Weak magnetic field measuring instrument and measuring method thereof

Abstract

The invention discloses a weak magnetic field measuring instrument and a measuring method thereof, and belongs to the technical field of weak magnetic field measurement. The weak magnetic field measuring instrument comprises a mounting platform, a pressure-sensitive sensor and two soft magnets are arranged on the mounting platform, a piezoelectric plate of the film pressure-sensitive sensor is arranged between the two soft magnets, a signal line of the film pressure-sensitive sensor is electrically connected with an external electric signal device, and a test magnet is arranged between the two soft magnets; two soft magnets are utilized to obtain an amplified magnetic field through a demagnetizing field effect, then the soft magnets and a magnet between the soft magnets apply pressure to a pressure sensor through the amplified magnetic field to output a specific signal, and finally the magnetic field intensity and direction of an external weak magnetic field are obtained by utilizing the output signal.

Description

Technical Field

[0001] The present invention relates to the technical field of weak magnetic field measurement, in particular to a weak magnetic field measuring instrument and a measuring method thereof. Background Art

[0002] Magnetic field measurement is an important technical means in the fields of physics, geophysics, biomedical engineering and materials science. With the rapid development of science and technology, various magnetic materials and their products are widely used in many fields such as electrical equipment, medical equipment, aerospace and wireless energy transmission.

[0003] Traditional magnetic field measurement technologies include fluxgate magnetometers, magnetoresistive magnetometers, etc. Although these technologies have high measurement accuracy, they still face challenges when measuring weak magnetic fields, such as interference from environmental noise and signal processing technology. Summary of the invention

[0004] In view of the above problems in the prior art, the present invention provides a weak magnetic field measuring instrument and a measuring method thereof, which solves the problem that the traditional magnetic field measuring technology is susceptible to interference from environmental noise when measuring weak magnetic fields.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0006] A weak magnetic field measuring instrument is provided, which comprises a mounting platform, on which a thin film pressure sensitive sensor and two soft magnets are arranged, a test magnet is arranged between the two soft magnets, a piezoelectric sheet of the thin film pressure sensitive sensor is arranged between the test magnet and one of the soft magnets, and a signal line of the thin film pressure sensitive sensor is electrically connected to an external electrical signal device.

[0007] Furthermore, a glass plate is arranged on the upper end surface of the mounting platform, and two soft magnets are arranged on the upper end surface of the glass plate; a gap is arranged in the middle of the glass plate, and the piezoelectric sheet of the thin film pressure sensitive sensor passes through the gap and is located between the two soft magnets.

[0008] Furthermore, the two soft magnets are both T-shaped structures, and the two soft magnets are symmetrically arranged with respect to the piezoelectric piece of the thin film pressure sensitive sensor, and the protruding ends of the two soft magnets are respectively located on both sides of the piezoelectric piece of the thin film pressure sensitive sensor.

[0009] Furthermore, the external electrical signal device is a multimeter.

[0010] The present invention also provides a measurement method of a weak magnetic field measuring instrument, which comprises:

[0011] Step 1, obtaining a curve function of the pressure-sensitive sensor output voltage and the magnetic field strength to be measured;

[0012] Step 2, record the initial resistance of the pressure sensitive sensor in the absence of a magnetic field;

[0013] Step 3, place the entire weak magnetic field measuring instrument into the magnetic field to be measured, and record the resistance value of the pressure sensitive sensor;

[0014] In step 4 and step 3, the resistance value of the pressure sensitive sensor is substituted into the pressure sensitive sensor output voltage-measured magnetic field strength curve function to calculate the magnetic field strength of the measured magnetic field.

[0015] Further, in step 1, the method for obtaining the curve function of the pressure-sensitive sensor output voltage-to-be-measured magnetic field strength includes:

[0016] Step 1.1, set the entire weak magnetic field measuring instrument in the Helmholtz coil;

[0017] Step 1.2, record the initial resistance value of the thin film pressure sensitive sensor;

[0018] Step 1.3, input 0.5V voltage to the Helmholtz coil; after waiting for 20 seconds, read and record the resistance value of the thin film pressure sensitive sensor and the strength of the magnetic field corresponding to the 0.5V voltage of the Helmholtz coil;

[0019] Step 1.4, disconnect the voltage input to the Helmholtz coil to return its magnetic field to zero, and the pressure-sensitive sensor returns to the initial resistance value;

[0020] Step 1.5, repeat steps 1.3 to 1.4, input a voltage of 0.5V to 10V to the Helmholtz coil, read and record the magnetic field strength of the Helmholtz coil at a voltage of 0.5V to 10V and the resistance value of the magnetic field strength of the thin film pressure sensitive sensor at a voltage of 0.5V to 10V;

[0021] Step 1.6, the magnetic field strength of the Helmholtz coil at a voltage of 0.5V to 10V and the resistance value of the magnetic field strength of the thin film pressure sensitive sensor at a voltage of 0.5V to 10V are input into the Matlab software for processing to obtain the pressure sensitive sensor output voltage-measured magnetic field strength curve function.

[0022] Furthermore, the expression of the pressure-sensitive sensor output voltage-to-be-measured magnetic field strength curve function is:

[0023] y=0.1451x 3 -3.75x 2 +33.71X-95.57

[0024] Wherein, y is the magnetic field strength of the magnetic field to be measured; x is the resistance value of the thin film pressure sensitive sensor.

[0025] The beneficial effects of the present invention are as follows: 1. A weak magnetic field measuring instrument and a measuring method thereof in the present invention utilize two soft magnets to obtain an amplified magnetic field through the demagnetization field effect, and then use the amplified magnetic field to make the soft magnets and the magnets between the soft magnets apply pressure to the pressure sensor to output a specific signal, and finally use the output signal to obtain the magnetic field strength and direction of the external weak magnetic field, thereby solving the problem that the traditional magnetic field measurement technology is susceptible to interference from environmental noise when measuring weak magnetic fields.

[0026] 2. The weak magnetic field measuring instrument of the present invention has a simple structure, is made of easily available materials, has a low manufacturing cost, and has high measurement accuracy, and is suitable for measuring weak magnetic fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the three-dimensional structure of a weak magnetic field measuring instrument.

[0028] Figure 2 This is the schematic diagram of the weak magnetic field measuring instrument.

[0029] Figure 3 It is a curve diagram of the output voltage of the pressure sensitive sensor-the magnetic field strength to be measured.

[0030] Figure 4 This is a schematic diagram of the top view structure of a weak magnetic field measuring instrument.

[0031] Among them, 1. Installation platform; 2. Thin film pressure sensitive sensor; 3. Soft magnet; 4. Signal line; 5. Glass plate; 6. Gap; 7. Test magnet. DETAILED DESCRIPTION

[0032] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0033] like Figure 1 and Figure 4 As shown, the present invention provides a weak magnetic field measuring instrument, which includes a mounting platform 1,

[0034] Two soft magnets 3 and a thin film pressure sensitive sensor 2 are arranged on the mounting platform 1, a test magnet 7 is arranged between the two soft magnets 3, the piezoelectric sheet of the thin film pressure sensitive sensor 2 is arranged between the test magnet 7 and one of the soft magnets 3, and the signal line 4 of the thin film pressure sensitive sensor 2 is electrically connected to an external electrical signal device. Specifically, the external electrical signal device is a multimeter. When the entire weak magnetic field measuring instrument is specifically set up, in order to prevent the soft magnet 3 and the test magnet 7 from moving too much, one of the soft magnets 3 is fixedly set.

[0035] The principle of the whole weak magnetic field measuring instrument is as follows: the test magnet 7 is set between two soft magnets 3, and the test magnet 7 is adsorbed on one of the soft magnets 3, and the piezoelectric sheet of the thin film pressure sensitive sensor 2 is set between the test magnet 7 and the soft magnet 3, and then the soft magnet 3 without the test magnet 7 is fixed. Since the test magnet 7 will magnetize the two soft magnets, a demagnetization field is generated between the two soft magnets 3, and the magnetic field direction of the demagnetization field is consistent with the magnetic field direction of the test magnet 7. When the whole weak magnetic field measuring instrument is placed in the weak magnetic field to be measured, the test magnet 7 will not be demagnetized because the magnetic field to be measured is relatively weak relative to the test magnet 7. When the direction of the magnetic field to be measured is opposite to the direction of the demagnetization field, the magnetization degree of the soft magnet 3 is weakened, and the demagnetization field is also weakened. At this time, due to the weakening of the attraction between the two soft magnets 3, the pressure applied to the sensor is weakened, so the resistance increases; if the direction of the magnetic field to be measured is the same as the direction of the demagnetization field, the resistance decreases, and finally the output signal of the thin film pressure sensitive sensor 2 is used to obtain the magnetic field strength and direction of the external weak magnetic field.

[0036] Preferably, a glass plate 5 is provided on the upper end surface of the mounting platform 1 , and two soft magnets 3 are provided on the upper end surface of the glass plate 5 ; a gap 6 is provided in the middle of the glass plate 5 , and the piezoelectric sheet of the thin film pressure sensitive sensor 2 passes through the gap 6 and is located between the two soft magnets 3 .

[0037] The two soft magnets 3 are both T-shaped, and the two soft magnets 3 are symmetrically arranged at the position of the piezoelectric sheet of the thin film pressure sensitive sensor 2, and the protruding ends of the two soft magnets 3 are respectively located on both sides of the piezoelectric sheet of the thin film pressure sensitive sensor 2. The two soft magnets 3 of the T-shaped structure can better gather the external weak magnetic field and realize the linear amplification of the magnetic field to be measured.

[0038] like Figure 2As shown, a weak magnetic field measuring instrument in the present invention uses two soft magnets 3 to obtain an amplified magnetic field through the demagnetization effect. The demagnetization effect refers to when a magnetic sample of a limited size is magnetized by an external magnetic field, the free magnetic poles appearing at its two ends will generate a magnetic field in the opposite direction of the magnetization intensity. In the present invention, the magnetic field is amplified so that the soft magnets 3 and the magnets between the soft magnets 3 apply pressure to the pressure sensor to output a specific signal, and finally the output signal is used to obtain the magnetic field strength and direction of the external weak magnetic field, which solves the problem that the traditional magnetic field measurement technology is easily interfered by environmental noise when measuring weak magnetic fields.

[0039] The present invention also provides a measurement method of a weak magnetic field measuring instrument, which comprises:

[0040] Step 1: Figure 3 As shown, the output voltage of the pressure sensitive sensor-the magnetic field strength curve function to be measured is obtained;

[0041] Step 2, record the initial resistance of the pressure sensitive sensor in the absence of a magnetic field;

[0042] Step 3, place the entire weak magnetic field measuring instrument into the magnetic field to be measured, and record the resistance value of the pressure sensitive sensor;

[0043] In step 4 and step 3, the resistance value of the pressure sensitive sensor is substituted into the pressure sensitive sensor output voltage-measured magnetic field strength curve function to calculate the magnetic field strength of the measured magnetic field.

[0044] Further, in step 1, the method for obtaining the curve function of the pressure-sensitive sensor output voltage-to-be-measured magnetic field strength includes:

[0045] Step 1.1, set the entire weak magnetic field measuring instrument in the Helmholtz coil;

[0046] Step 1.2, recording the initial resistance value of the thin film pressure sensitive sensor 2;

[0047] Step 1.3, input 0.5V voltage to the Helmholtz coil; after waiting for 20 seconds, read and record the resistance value of the thin film pressure sensitive sensor 2 and the strength of the magnetic field corresponding to the 0.5V voltage of the Helmholtz coil;

[0048] Step 1.4, disconnect the voltage input to the Helmholtz coil to return its magnetic field to zero, and the pressure-sensitive sensor returns to the initial resistance value;

[0049] Step 1.5, repeat steps 1.3 to 1.4, input a voltage of 0.5V to 10V to the Helmholtz coil, read and record the magnetic field strength of the Helmholtz coil at a voltage of 0.5V to 10V and the resistance value of the magnetic field strength of the thin film pressure sensitive sensor 2 at a voltage of 0.5V to 10V;

[0050] Step 1.6, the magnetic field strength of the Helmholtz coil at a voltage of 0.5V to 10V and the resistance value of the magnetic field strength of the thin film pressure sensitive sensor 2 at a voltage of 0.5V to 10V are input into the Matlab software for processing to obtain the pressure sensitive sensor output voltage-measured magnetic field strength curve function.

[0051] Furthermore, the expression of the pressure-sensitive sensor output voltage-to-be-measured magnetic field strength curve function is:

[0052] y=0.1451x 3 -3.75x 2 +33.71X-95.57

[0053] Wherein, y is the magnetic field strength of the magnetic field to be measured; x is the resistance value of the thin film pressure sensitive sensor 2.

Claims

1. A weak magnetic field measuring instrument, characterized in that: It includes an installation platform, on which a thin film pressure sensitive sensor and two soft magnets are arranged, a test magnet is arranged between the two soft magnets, the piezoelectric sheet of the thin film pressure sensitive sensor is arranged between the test magnet and one of the soft magnets, and the signal line of the thin film pressure sensitive sensor is electrically connected to an external electrical signal device.

2. The weak magnetic field measuring instrument according to claim 1, characterized in that: A glass plate is arranged on the upper end surface of the installation platform, and two soft magnets are arranged on the upper end surface of the glass plate; a gap is arranged in the middle of the glass plate, and the piezoelectric sheet of the thin film pressure sensitive sensor passes through the gap and is located between the two soft magnets.

3. The weak magnetic field measuring instrument according to claim 2, characterized in that: The two soft magnets are both T-shaped structures, and the two soft magnets are symmetrically arranged with respect to the position of the piezoelectric piece of the thin film pressure sensitive sensor, and the raised ends of the two soft magnets are respectively located on both sides of the piezoelectric piece of the thin film pressure sensitive sensor.

4. The weak magnetic field measuring instrument according to claim 3, characterized in that: The external electrical signal device is a multimeter.

5. A measurement method based on the weak magnetic field measuring instrument described in any one of claims 1 to 4, characterized in that: include: Step 1, obtaining a curve function of the pressure-sensitive sensor output voltage and the magnetic field strength to be measured; Step 2, record the initial resistance of the pressure sensitive sensor in the absence of a magnetic field; Step 3, place the entire weak magnetic field measuring instrument into the magnetic field to be measured, and record the resistance value of the pressure sensitive sensor; In step 4 and step 3, the resistance value of the pressure sensitive sensor is substituted into the pressure sensitive sensor output voltage-measured magnetic field strength curve function to calculate the magnetic field strength of the measured magnetic field.

6. The measuring method of the weak magnetic field measuring instrument according to claim 5, characterized in that: In step 1, the method for obtaining a curve function of the pressure-sensitive sensor output voltage and the magnetic field strength to be measured includes: Step 1.1, set the entire weak magnetic field measuring instrument in the Helmholtz coil; Step 1.2, record the initial resistance value of the thin film pressure sensitive sensor; Step 1.3, input 0.5V voltage to the Helmholtz coil; after waiting for 20 seconds, read and record the resistance value of the thin film pressure sensitive sensor and the strength of the magnetic field corresponding to the 0.5V voltage of the Helmholtz coil; Step 1.4, disconnect the voltage input to the Helmholtz coil to return its magnetic field to zero, and the pressure-sensitive sensor returns to the initial resistance value; Step 1.5, repeat steps 1.3 to 1.4, input a voltage of 0.5V to 10V to the Helmholtz coil, read and record the magnetic field strength of the Helmholtz coil at a voltage of 0.5V to 10V and the resistance value of the magnetic field strength of the thin film pressure sensitive sensor at a voltage of 0.5V to 10V; Step 1.6, the magnetic field strength of the Helmholtz coil at a voltage of 0.5V to 10V and the resistance value of the magnetic field strength of the thin film pressure sensitive sensor at a voltage of 0.5V to 10V are input into the Matlab software for processing to obtain the pressure sensitive sensor output voltage-measured magnetic field strength curve function.

7. The measuring method of the weak magnetic field measuring instrument according to claim 6, characterized in that: The expression of the pressure sensor output voltage-to-measure magnetic field strength curve function is: y=0.1451x 3 -3.75x 2 +33.71x-95.57 Wherein, y is the magnetic field strength of the magnetic field to be measured; x is the resistance value of the thin film pressure sensitive sensor.

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