Flexible GMR magnetic field vector sensor and preparation method thereof

Abstract

The invention discloses a flexible GMR magnetic field vector sensor which is characterized in that the sensor comprises three flexible arrays which are bent into a ring shape, each flexible array comprises a flexible substrate and a magnetic field sensor arranged on the flexible substrate, and the three flexible arrays are mutually orthogonal to form a spherical skeleton structure. The flexible GMR magnetic field vector sensor disclosed by the invention can realize accurate measurement of magnetic field components parallel to x, y and z axis directions, is low in cost, simple to operate and easy to implement, and has the advantages of high flexibility and miniaturization.

Description

Technical Field

[0001] The present invention relates to a flexible GMR magnetic field vector sensor and a preparation method thereof, belonging to the technical field of sensors. Background Art

[0002] At present, the same magnetic sensitive element can only detect the magnetic field information in a single direction in-plane or out-of-plane. For the multi-directional magnetic field measurement required in many application scenarios, a single magnetic field sensor cannot be realized. In practical applications, multiple magnetic sensitive elements are encapsulated and integrated on a printed circuit board to achieve magnetic field measurement in different directions. However, affected by the magnetic sensitivity difference of different magnetic sensitive elements, there is a problem of poor magnetic sensitivity consistency, which further affects the performance of the magnetic field vector sensor.

[0003] Therefore, it is necessary to conduct in-depth research on existing sensors to solve the above problems. Summary of the Invention

[0004] In order to overcome the above problems, the inventor of the present invention proposes a flexible GMR magnetic field vector sensor, as Figure 1 shown, Figure 2 shown, including three flexible arrays 1 bent into a ring shape. Each flexible array 1 includes a flexible substrate 11 and a magnetic field sensor 12 disposed on the flexible substrate.

[0005] In a preferred embodiment, the three flexible arrays are orthogonal to each other and respectively measure the magnetic fields in the x-axis direction, y-axis direction, and z-axis direction. Among them, B x1 represents the magnetic field in the first direction of the x-axis; B x2 represents the magnetic field in the second direction of the x-axis, B y1 represents the magnetic field in the first direction of the y-axis; B y2 represents the magnetic field in the second direction of the y-axis; B z1 represents the magnetic field in the first direction of the z-axis; B z2 represents the magnetic field in the second direction of the z-axis.

[0006] In a preferred embodiment, a plurality of magnetic field sensors are disposed on each flexible array

[0007] In a preferred embodiment, the magnetic field sensor is a GMR magnetic field sensor.

[0008] In a preferred embodiment, each magnetic field sensor includes 4 giant magnetoresistors 121, and the 4 giant magnetoresistors form a Wheatstone bridge structure through metal electrodes, as Figure 4 shown.

[0009] In a preferred embodiment, the magnetic sensitive directions between adjacent giant magnetoresistors are 90°.

[0010] In a preferred embodiment, any magnetic induction intensity B in a three-dimensional rectangular coordinate system can be decomposed into three magnetic field components along the x-axis, y-axis, and z-axis. γ is the angle between B and B y , and φ is the angle between the projection of B on the xz plane and B x . The average value of multiple magnetic field sensors in the same direction is used as the result of the magnetic field component in that direction.

[0011] The magnetic field sensors on the x-axis direction array detect the tangential magnetic field parallel to the x-axis direction and take the average value to obtain the magnetic field component in the x-axis direction.

[0012] The magnetic field sensors on the y-axis direction array detect the tangential magnetic field parallel to the y-axis direction and take the average value to obtain the magnetic field component in the y-axis direction.

[0013] The magnetic field sensors on the z-axis direction array detect the tangential magnetic field parallel to the z-axis direction and take the average value to obtain the magnetic field component in the z-axis direction.

[0014] The present invention also discloses a preparation method of the above-mentioned flexible GMR magnetic field vector sensor, including the following steps:

[0015] Step 1: Prepare a flexible substrate on a substrate.

[0016] Step 2: Clean the dried flexible substrate, spin-coat a bottom glue and a photoresist on the upper surface of the flexible substrate for the first photolithography to form a giant magnetoresistive strip window.

[0017] Step 3: Magnetron sputtering coating to prepare a giant magnetoresistive multi-layer film, and use a stripping solution to remove the bottom glue and the photoresist on the surface of the flexible substrate to form a giant magnetoresistive strip structure.

[0018] Step 4: Clean the substrate, and then spin-coat a bottom glue and a photoresist on the upper surface of the flexible substrate for the second photolithography to form an electrode window.

[0019] Step 5: Vacuum coating, fabricate electrode materials on the upper surface of the flexible substrate, and use a stripping solution to remove the bottom glue and the photoresist on the surface of the flexible substrate to form a metal electrode.

[0020] Step 6: Prepare a layer of PI film on the surface of the metal electrode to play a protective role.

[0021] Step 7: Peel off the flexible substrate on the substrate to obtain a bendable flexible array.

[0022] Step 8: Orthogonally arrange three flexible arrays into a spherical skeleton structure to obtain a flexible GMR magnetic field vector sensor.

[0023] In a preferred embodiment, Step 1 includes the following sub-steps:

[0024] Step 11: Uniformly disperse ODA (4,4'-diaminodiphenyl ether) in a DMAc (N,N-dimethylacetamide) solvent to obtain a mixed solution;

[0025] Step 12: Add PMDA (pyromellitic dianhydride) to the mixed solution and continuously stir to obtain a polyamic acid mixed colloid;

[0026] Step 13: Vacuum the PAA (polyamic acid) mixed colloid to remove air bubbles;

[0027] Step 14: Coat the PAA (polyamic acid) mixed colloid on a substrate;

[0028] Step 15: Perform thermal imidization on the substrate to complete the preparation of the flexible substrate.

[0029] In a preferred embodiment, in Step 12, divide PMDA (pyromellitic dianhydride) into multiple portions and add them to the mixed solution in multiple times for mixing. After mixing, continuously stir for 5 - 8 h.

[0030] The beneficial effects of the present invention include:

[0031] (1) The spherical skeleton structure magnetic field vector sensor constituted by the present invention can achieve precise measurement of the magnetic field components parallel to the x, y, and z axes;

[0032] (2) The present invention uses the same magnetic sensitive element, and the magnetic sensitivities in three directions are in good consistency, improving the performance of the magnetic field vector sensor.

[0033] (3) The preparation process method of the present invention has low cost, simple operation, is easy to implement, and has the advantages of high flexibility and miniaturization.

[0034] Symbol Explanation

[0035] 1 - Flexible array; 11 - Flexible substrate; 12 - Magnetic field sensor; 121 - Giant magnetoresistance;

[0036] B x1 - Magnetic field in the first direction of the x-axis; B x2 - Magnetic field in the second direction of the x-axis; B y1 - Magnetic field in the first direction of the y-axis; B y2 - Magnetic field in the second direction of the y-axis; B z1 - Magnetic field in the first direction of the z-axis; B z2 - Magnetic field in the second direction of the z-axis; R x1 - First giant magnetoresistance of the x-axis; R x2 - Second giant magnetoresistance of the x-axis; R x3 - Third giant magnetoresistance of the x-axis; R x4 - Fourth giant magnetoresistance of the x-axis; R x5- Fifth giant magnetoresistance along the -x axis; R x6 - Sixth giant magnetoresistance along the -x axis; R x7 - Seventh giant magnetoresistance along the -x axis; R x8 - Eighth giant magnetoresistance along the -x axis; R x9 - Ninth giant magnetoresistance along the -x axis; R x10 - Tenth giant magnetoresistance along the -x axis; R x11 - Eleventh giant magnetoresistance along the -x axis; R x12 - Twelfth giant magnetoresistance along the -x axis; R x13 - Thirteenth giant magnetoresistance along the -x axis; R x14 - Fourteenth giant magnetoresistance along the -x axis; R x15 - Fifteenth giant magnetoresistance along the -x axis; R x16 - Sixteenth giant magnetoresistance along the -x axis;

[0037] V outx1 - First output voltage along the -x axis; V outx2 - Second output voltage along the -x axis; V outx3 - Third output voltage along the -x axis; V outx4 - Fourth output voltage along the -x axis; V outx5 - Fifth output voltage along the -x axis; V outx6 - Sixth output voltage along the -x axis; V outx7 - Seventh output voltage along the -x axis; V outx8 - Eighth output voltage along the -x axis; V DD - Power supply; GND - Ground. Brief Description of the Drawings

[0038] Figure 1 Shows the overall structural schematic diagram of a flexible GMR magnetic field vector sensor according to a preferred embodiment of the present invention;

[0039] Figure 2 Shows the flexible array structural schematic diagram of a flexible GMR magnetic field vector sensor according to a preferred embodiment of the present invention;

[0040] Figure 3 Shows the equivalent circuit diagram of the magnetic field sensor for measuring the magnetic field in the x-axis direction of a flexible GMR magnetic field vector sensor according to a preferred embodiment of the present invention;

[0041] Figure 4 Shows the structural schematic diagram of the magnetic field sensor for measuring the magnetic field in the x-axis direction of a flexible GMR magnetic field vector sensor according to a preferred embodiment of the present invention;

[0042] Figure 5 Shows the test results in Experimental Example 1. Detailed Description of the Invention

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become more clear and definite.

[0044] As used herein, the term "exemplary" means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" herein need not be construed as superior or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0045] A flexible GMR magnetic field vector sensor provided according to the present invention includes three flexible arrays 1 bent into a ring shape. Each flexible array 1 includes a flexible substrate 11 and a magnetic field sensor 12 disposed on the flexible substrate.

[0046] The three flexible arrays 1 are orthogonal to each other to form a spherical skeleton structure.

[0047] Preferably, the magnetic field sensor is a GMR magnetic field sensor. The GMR magnetic field sensor is a thin film structure, which has many advantages such as low power consumption, high reliability, small volume, and can work in harsh environments.

[0048] Preferably, each flexible array includes at least 2 GMR magnetic field sensors. More preferably, 4 or more GMR magnetic field sensors are provided. Through multiple tests, it can be known that setting 4 magnetic field sensors can obtain sufficient magnetic field information to avoid information loss.

[0049] Further, each magnetic field sensor includes 4 giant magnetoresistors 121. The 4 giant magnetoresistors form a Wheatstone bridge structure through metal electrodes. Under the action of an external magnetic field, the change in the resistance value causes the output electrical signal of the Wheatstone bridge to change, enabling the magnetic field sensor to measure the magnetic field component in one direction.

[0050] More preferably, the magnetic sensitive directions between adjacent giant magnetoresistors are 90°.

[0051] Preferably, the average value of multiple magnetic field sensors in the same direction is used as the result of the magnetic field component in that direction. For example, the magnetic field sensors on the x-axis direction array detect the tangential magnetic field parallel to the x-axis direction and take the average value to obtain the magnetic field component in the x-axis direction; the same applies to the y-axis and z-axis directions.

[0052] In the present invention, the structures of the magnetic field sensors in the x-axis direction, y-axis direction, and z-axis direction are the same. Figure 3 Shows a Wheatstone bridge circuit structure formed by 4 giant magnetoresistors in the x-axis direction through metal electrodes, where R x1 represents the first giant magnetoresistor in the x-axis; R x2 represents the second giant magnetoresistor in the x-axis; R x3Represents the third giant magnetoresistance of the x-axis; R x4 Represents the fourth giant magnetoresistance of the x-axis; R x5 Represents the fifth giant magnetoresistance of the x-axis; R x6 Represents the sixth giant magnetoresistance of the x-axis; R x7 Represents the seventh giant magnetoresistance of the x-axis; R x8 Represents the eighth giant magnetoresistance of the x-axis; R x9 Represents the ninth giant magnetoresistance of the x-axis; R x10 Represents the tenth giant magnetoresistance of the x-axis; R x11 Represents the eleventh giant magnetoresistance of the x-axis; R x12 Represents the twelfth giant magnetoresistance of the x-axis; R x13 Represents the thirteenth giant magnetoresistance of the x-axis; R x14 Represents the fourteenth giant magnetoresistance of the x-axis; R x15 Represents the fifteenth giant magnetoresistance of the x-axis; R x16 Represents the sixteenth giant magnetoresistance of the x-axis, V outx1 Represents the first output voltage of the x-axis; V outx2 Represents the second output voltage of the x-axis; V outx3 Represents the third output voltage of the x-axis; V outx4 Represents the fourth output voltage of the x-axis; V outx5 Represents the fifth output voltage of the x-axis; V outx6 Represents the sixth output voltage of the x-axis; V outx7 Represents the seventh output voltage of the x-axis; V outx8 Represents the eighth output voltage of the x-axis, V DD Represents the power supply, GND represents the ground; the same applies to the y-axis direction and the z-axis direction, which are not shown in the present invention.

[0053] Forming a Wheatstone bridge can significantly improve the measurement performance. The resistance of a single magnetic field sensor (such as an anisotropic magnetoresistive element) changes with the magnetic field, but its output is vulnerable to interference such as temperature drift and power supply fluctuations. If multiple sensors are directly connected in parallel or in series, although the sensitivity may be improved, it is difficult to eliminate the common-mode interference, and the signal processing complexity is relatively high. When four giant magnetoresistances form a Wheatstone bridge, the symmetric structure of the bridge can cancel out the resistance changes caused by environmental factors such as temperature, and can significantly improve the measurement stability, linearity and sensitivity.

[0054] In the present invention, the specific material of the flexible substrate is not limited, and those skilled in the art can freely choose according to actual needs. For example, one of PI, PET, PEN, PDMS or Kapton can be used. PI film has the advantages of high toughness, high temperature resistance, electrical insulation and corrosion resistance. The preparation method is simple, the polymerization temperature is low, the yield is high and the product performance is good. Therefore, PI is preferably used.

[0055] In the GMR magnetic field sensor, the magnetic layer material is one of Co, Fe, Ni, CoFe, CoFeB or NiFe. Since the multi-layer film composed of Co magnetic layer will exhibit a larger magnetoresistivity, Co is preferably used.

[0056] In the GMR magnetic field sensor, the non-magnetic layer material is one of Cr, Au, Ag, Cu, Ru or Mo. The contribution of spin-dependent scattering to the giant magnetoresistance effect is much greater at the Co / Cu interface, so Cu is preferably used.

[0057] In the flexible array, the material of the metal electrode is not limited and can be one of Au, Ag, Al, Cu or Pt, and Al is preferably used.

[0058] The present invention also provides a method for preparing a flexible GMR magnetic field vector sensor for preparing the above-mentioned flexible GMR magnetic field vector sensor, including the following steps:

[0059] Step 1: Prepare a flexible substrate on a substrate;

[0060] Step 2: Clean the dried flexible substrate, spin-coat a bottom glue and a photoresist on the upper surface of the flexible substrate for the first photolithography to form a giant magnetoresistance strip window;

[0061] Step 3: Magnetron sputtering coating to prepare a giant magnetoresistance multi-layer film, and use a stripping solution to remove the bottom glue and the photoresist on the surface of the flexible substrate to form a giant magnetoresistance strip structure;

[0062] Step 4: Clean the substrate, and then spin-coat a bottom glue and a photoresist on the upper surface of the flexible substrate for the second photolithography to form an electrode window;

[0063] Step 5: Vacuum coating, make the electrode material on the upper surface of the flexible substrate, and use a stripping solution to remove the bottom glue and the photoresist on the surface of the flexible substrate to form a metal electrode;

[0064] Step 6: Prepare a layer of PI film on the surface of the metal electrode to play a protective role;

[0065] Step 7: Peel off the flexible substrate on the substrate to obtain a bendable flexible array;

[0066] Step 8: Orthogonally arrange three flexible arrays into a spherical skeleton structure to obtain a flexible GMR magnetic field vector sensor.

[0067] Preferably, in step 1, a flexible substrate is prepared on a single-crystal silicon substrate;

[0068] Preferably, in step 1, the flexible substrate is a PI flexible substrate.

[0069] Preferably, step 1 includes the following sub-steps:

[0070] Step 11: Uniformly disperse ODA (4,4'-diaminodiphenyl ether) in a DMAc (N,N-dimethylacetamide) solvent to obtain a mixed solution;

[0071] Step 12: Add PMDA (pyromellitic dianhydride) to the mixed solution and continuously stir to obtain a PAA (polyamic acid) mixed colloid;

[0072] Step 13: Evacuate the PAA mixed colloid to remove air bubbles;

[0073] Step 14: Coat the PAA mixed colloid on a substrate;

[0074] Step 15: Perform thermal imidization on the substrate to complete the preparation of the flexible substrate.

[0075] More preferably, in Step 11, ultrasonic oscillation is carried out to uniformly disperse ODA in the DMAc solvent.

[0076] More preferably, in Step 12, divide PMDA (pyromellitic dianhydride) into multiple portions and add them to the mixed solution in multiple times, and perform mechanical stirring. The solution gradually becomes viscous as PMDA (pyromellitic dianhydride) is added, and continue to stir at room temperature for 5 - 8 h to obtain a PAA (polyamic acid) mixed colloid with sufficient molecular weight.

[0077] More preferably, in Step 13, the evacuation time is not less than 12 hours to ensure the removal of air bubbles.

[0078] More preferably, in Step 14, the coating thickness is 250 - 350 μm, preferably 300 μm. When selecting the thickness of the PI film, it needs to be optimized according to specific requirements. For example, in the microelectronics field, a thinner PI film may be required to achieve higher precision and performance; while in some applications that need to withstand greater mechanical stress, a thicker PI film may be required to provide sufficient strength and durability.

[0079] More preferably, in Step 15, during the thermal imidization process, the temperature is raised in a gradient manner, the temperature range is 80°C - 350°C, the temperature is raised by 50°C - 70°C every 1 hour, for example 60°C, and maintained at 350°C for 1 hour or more.

[0080] Preferably, in Step 2, the cleaning is performed by low-frequency ultrasonic cleaning. More preferably, the dried flexible substrate is successively placed in anhydrous ethanol and acetone for low-frequency ultrasonic cleaning.

[0081] Preferably, the first lithography is completed by a photolithographic mask exposure process.

[0082] Preferably, in step 3, the substrate after the first lithography is placed in a magnetron sputtering coating system to prepare a giant magnetoresistance multi-layer film. The substrate is immersed in a stripping solution to remove the underlayer glue and photoresist on the surface of the flexible substrate, forming a giant magnetoresistance strip structure.

[0083] Preferably, in step 4, the stripped substrate is ultrasonically cleaned at a low frequency in anhydrous ethanol and acetone.

[0084] Preferably, in step 4, a second lithography is performed using an electrode lithography mask plate to form an electrode window.

[0085] Preferably, in step 5, the substrate is placed in a vacuum coating machine, and the electrode material is fabricated on the upper surface of the flexible substrate. The substrate is immersed in a stripping solution to remove the underlayer glue and photoresist on the surface of the flexible substrate, forming a metal electrode.

[0086] Preferably, after step 7, the flexible array is also encapsulated. For example, it is mounted on a flexible circuit board through a sealant, and the Pad points on the flexible GMR magnetic field vector sensor are connected to the pressure solder joints on the flexible circuit board using conductive silver paste to complete the encapsulation.

[0087] It should be understood that various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitations are imposed herein.

[0088] Embodiment

[0089] A flexible GMR magnetic field vector sensor is prepared. The sensor includes three flexible arrays bent into a ring shape, and each flexible array includes a flexible substrate and a plurality of magnetic field sensors disposed on the flexible substrate.

[0090] The three flexible arrays are orthogonal to each other to form a spherical skeleton structure.

[0091] Each flexible array is provided with 4 GMR magnetic field sensors, and each GMR magnetic field sensor constitutes a Wheatstone bridge structure through 4 giant magnetoresistances and metal electrodes.

[0092] In the GMR magnetic field sensor, the magnetic layer material is Co, and the non-magnetic layer material is Cu.

[0093] It is prepared by the following method:

[0094] Step 1: Prepare a flexible substrate on a substrate;

[0095] Step 2: Clean the dried flexible substrate, spin-coat an underlayer glue and photoresist on the upper surface of the flexible substrate, and perform the first lithography to form a giant magnetoresistance strip window;

[0096] Step 3: Magnetron sputtering coating to prepare a giant magnetoresistance multi-layer film. Use a stripping solution to remove the bottom glue and photoresist on the surface of the flexible substrate, forming a giant magnetoresistance strip structure;

[0097] Step 4: Substrate cleaning. Then, spin-coat the bottom glue and photoresist on the upper surface of the flexible substrate for the second photolithography to form an electrode window;

[0098] Step 5: Vacuum coating. Fabricate the electrode material on the upper surface of the flexible substrate. Use a stripping solution to remove the bottom glue and photoresist on the surface of the flexible substrate, forming a metal electrode;

[0099] Step 6: Prepare a layer of PI film on the surface of the metal electrode to play a protective role;

[0100] Step 7: Peel off the flexible substrate on the substrate to obtain a bendable flexible array;

[0101] Step 8: Orthogonally arrange three flexible arrays to form a spherical skeleton structure to obtain a flexible GMR magnetic field vector sensor.

[0102] In Step 1, preparing a PI flexible substrate on a single-crystalline silicon substrate includes the following sub-steps:

[0103] Step 11: Uniformly disperse 3 g of ODA (4,4'-diaminodiphenyl ether) in 40 ml of DMAc (N,N-dimethylacetamide) solvent, and ultrasonically vibrate for 3 min to obtain a mixed solution;

[0104] Step 12: Add 3.28 g of PMDA (pyromellitic dianhydride) to the mixed solution, and continuously stir at room temperature for 5 - 8 h to obtain a PAA (polyamic acid) mixed colloid;

[0105] Step 13: Vacuumize the PAA (polyamic acid) mixed colloid for 12 h to remove air bubbles;

[0106] Step 14: Coat the PAA (polyamic acid) mixed colloid on the substrate with a thickness of 300 μm;

[0107] Step 15: Perform gradient temperature rise thermal imidization on the substrate, raise the temperature by 60 °C every 1 h during the period of 80 °C - 350 °C, and maintain at 350 °C for 1 h to complete the preparation of the flexible substrate.

[0108] In Step 3, the substrate after the first photolithography is placed into a magnetron sputtering coating system to fabricate a giant magnetoresistive multilayer film. The substrate is immersed in a stripping solution to remove the bottom glue and photoresist on the surface of the flexible substrate, forming a giant magnetoresistive strip structure. The sputtering power is set to 60 W, the sputtering time for the Co layer is 10 s, the sputtering time for the Cu layer is 60 s, the number of cycles is 25, the width of the resistor strip of the giant magnetoresistive multilayer film is 150 μm, and the length is 23550 μm.

[0109] In Step 4, the stripped substrate is ultrasonically cleaned at low frequency in anhydrous ethanol and acetone.

[0110] In Step 5, the substrate is placed into a vacuum coating machine, and the electrode material is fabricated on the upper surface of the flexible substrate. The substrate is immersed in a stripping solution to remove the bottom glue and photoresist on the surface of the flexible substrate, forming a metal electrode. The size of the Al electrode is 1800 μm × 2500 μm, and the thickness is 300 - 500 nm.

[0111] Experimental Example

[0112] The input-output characteristics of the fabricated flexible GMR magnetic field vector sensor under a constant magnetic field are tested using a high and low temperature Hall effect test system (CH-100), which includes a full digital high-resolution gaussmeter (CH-1500), a high-precision digital power supply (F2030), a programmable linear DC power supply (RIGOL DP832A), a constant current source (SD-120), and a data acquisition box (CH-UA500-1). During the test, the magnetic field change range for the forward stroke is -200 mT to 200 mT; the step size is 10 mT, and the magnetic field change range for the reverse stroke is 200 to -200 mT, and the step size is -10 mT.

[0113] Figure 5 Shows the curve of the sensor output voltage changing with the applied magnetic field under a constant magnetic field. The sensitivity is calculated to be 1.29 μV / mT within the linear region of the magnetic field range of -100 to 100 mT. It can be seen that the flexible GMR magnetic field vector sensor obtained in the embodiment has a relatively high measurement accuracy for the magnetic field.

[0114] The present invention has been described in combination with preferred embodiments above, but these embodiments are only exemplary and only serve an illustrative purpose. On this basis, various substitutions and improvements can be made to the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A flexible GMR magnetic field vector sensor, characterized in that It includes three flexible arrays bent into a ring shape. Each flexible array includes a flexible substrate and a magnetic field sensor disposed on the flexible substrate. The three flexible arrays are orthogonal to each other to form a spherical framework structure.

2. The flexible GMR magnetic field vector sensor according to claim 1, wherein Multiple magnetic field sensors are disposed on each flexible array.

3. The flexible GMR magnetic field vector sensor according to claim 1, wherein The magnetic field sensor is a GMR magnetic field sensor.

4. The flexible GMR magnetic field vector sensor according to claim 3, wherein Each magnetic field sensor includes 4 giant magnetoresistances, and the 4 giant magnetoresistances form a Wheatstone bridge structure.

5. The flexible GMR magnetic field vector sensor according to claim 4, wherein The magnetic sensitive directions between adjacent giant magnetoresistances are at 90°.

6. A preparation method of the flexible GMR magnetic field vector sensor as described in any one of claims 1-5, characterized in that, It includes the following steps: Step 1: Prepare a flexible substrate on a substrate; Step 2: Clean the dried flexible substrate, spin-coat a bottom glue and a photoresist on the upper surface of the flexible substrate for the first photolithography to form a giant magnetoresistance strip window; Step 3: Magnetron sputtering coating to prepare a giant magnetoresistance multi-layer film, and use a stripping solution to remove the bottom glue and the photoresist on the surface of the flexible substrate to form a giant magnetoresistance strip structure; Step 4: Clean the substrate, and then spin-coat a bottom glue and a photoresist on the upper surface of the flexible substrate for the second photolithography to form an electrode window; Step 5: Vacuum coating, make electrode materials on the upper surface of the flexible substrate, and use a stripping solution to remove the bottom glue and the photoresist on the surface of the flexible substrate to form a metal electrode; Step 6: Prepare a layer of PI film on the surface of the metal electrode to play a protective role; Step 7: Peel off the flexible substrate on the substrate to obtain a bendable flexible array; Step 8: Orthogonally arrange the three flexible arrays into a spherical framework structure to obtain a flexible GMR magnetic field vector sensor.

7. The preparation method of the flexible GMR magnetic field vector sensor according to claim 6, wherein Step 1 includes the following sub-steps: Step 11: Uniformly disperse 4,4'-diaminodiphenyl ether in an N,N-dimethylacetamide solvent to obtain a mixed solution; Step 12: Add pyromellitic dianhydride to the mixed solution and continuously stir to obtain a polyamic acid mixed colloid; Step 13: Vacuumize the polyamic acid mixed colloid to remove air bubbles; Step 14: Coat the polyamic acid mixed colloid on the substrate; Step 15: Perform thermal imidization on the substrate to complete the preparation of the flexible substrate.

8. The preparation method of the flexible GMR magnetic field vector sensor according to claim 7, wherein In Step 12, pyromellitic dianhydride is divided into multiple portions and added to the mixed solution in multiple times for mixing, and after mixing, continuously stir for 5 to 8 hours.

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