CN116136578A - Magnetic field emitter and magnetic field sensor - Google Patents

Abstract

The invention provides a magnetic field emitter and a magnetic field sensor. The magnetic field transmitter comprises one or more transmitting units. The transmitting unit includes a planar transmitting coil. The planar transmitting coil is a spiral coil formed by winding a wire on a plane according to a polygon. The number of sides of the polygon is greater than two. The magnetic field sensor comprises a sensing unit. The sensing unit includes a planar sensing coil. A planar sensing coil is a spiral coil formed by a wire wound on a plane according to a geometric shape. The wires on the plane are not overlapped. Thus, miniaturization, thinning and/or high density of the wiring can be achieved.

Description

Magnetic field emitter and magnetic field sensor

Technical Field

The invention relates to an electromagnetic field positioning technology, in particular to a magnetic field emitter and a magnetic field sensor which are suitable for electromagnetic field positioning.

Background

The electromagnetic positioning system may establish a controllable magnetic Field space through an electromagnetic Field Generator (FG) (e.g., a transmitting coil) to determine the position and/or orientation of a magnetic sensing coil in the space. Thus, electromagnetic positioning is often used in medical, robotic and virtual reality applications where accuracy is required.

Notably, electromagnetic field generators typically employ a wire-wound set design. However, such designs are not conducive to meeting the demands for miniaturization, thinness, and/or high density of wiring. Even this design may not be uniform in spatial magnetic field strength and it is difficult to stabilize magnetic field control.

Disclosure of Invention

The invention aims at a magnetic field emitter and a magnetic field sensor, and the planar design meets the requirements of miniaturization, thinness and/or high density of circuits.

According to an embodiment of the invention, the magnetic field transmitter comprises one or more transmitting units. The transmitting unit includes a planar transmitting coil. The planar transmitting coil is a spiral coil formed by winding a wire on a plane according to a polygon. The number of sides of the polygon is greater than two.

According to an embodiment of the invention, the magnetic field sensor comprises a sensing unit. The sensing unit includes a planar sensing coil. A planar sensing coil is a spiral coil formed by a wire wound on a plane according to a geometric shape. The wires on the plane are not overlapped.

Based on the above, the magnetic field emitter and the magnetic field sensor according to the embodiments of the present invention provide a planar spiral coil, thereby achieving miniaturization, thinness, and/or high density of the wiring.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIGS. 1A-1C are schematic diagrams of a system according to an embodiment of the invention;

FIG. 2A is a schematic diagram of a planar transmit coil according to an embodiment of the present invention;

FIG. 2B is a schematic diagram of a planar transmit coil according to another embodiment of the present invention;

FIG. 2C is a schematic diagram of a planar transmit coil according to yet another embodiment of the present invention;

FIG. 3A is a side view of a firing cell according to one embodiment of the present invention;

FIG. 3B is a perspective view of FIG. 3A;

FIG. 3C is a top view of FIG. 3A;

FIGS. 4A-4C are schematic illustrations of magnetic field strength distributions according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a magnetic field transmitter according to an embodiment of the invention;

FIG. 6 is a schematic diagram illustrating a transmit array according to one embodiment of the invention;

FIG. 7 is a schematic diagram of a magnetic field transmitter according to an embodiment of the invention;

FIGS. 8A-8D are schematic illustrations of magnetic field strength according to an embodiment of the invention;

FIGS. 9A-9E are schematic illustrations of magnetic field strength according to an embodiment of the invention;

FIG. 10A is a schematic diagram of a planar sense coil in accordance with an embodiment of the present invention;

FIG. 10B is a schematic diagram of a planar sense coil in accordance with another embodiment of the present invention;

FIG. 10C is a schematic diagram of a planar sense coil in accordance with yet another embodiment of the present invention;

FIG. 10D is a schematic diagram of a planar sense coil in accordance with yet another embodiment of the present invention;

FIG. 11 is a schematic diagram of a magnetic field sensor according to an embodiment of the invention;

fig. 12A is an equivalent circuit diagram of a signal processing circuit according to an embodiment of the present invention;

fig. 12B is a frequency response diagram according to an embodiment of the invention.

Description of the reference numerals

1, a system;

p, figures;

10. 10B, 10C electromagnetic emitters;

11. tx1 to Tx8, a transmitting unit;

11A to 11C, 12: a planar transmitting coil;

50, a magnetic field sensor;

d1 _out 、d2 _out 、d3 _out 、d4 _out 、d5 _out 、d6 _out 、d7 _out maximum outer diameter;

d1 _in 、d2 _in 、d3 _in 、d4 _in 、d5 _in 、d6 _in 、d7 _in the minimum inner diameter;

w1, w2, w3, w4, w5, w6, w7: width;

s1, s2, s3, s4, s5, s6, s 7;

theta 1-theta 3, theta 5-theta 7;

in, the distance;

th is the thickness;

13, shielding structure;

c, current;

x, y;

ax1, ax2, ay1, ay 2;

dS1, dS2, dA1, dA2, dA3, dA 4;

a1 and A2 are areas;

15, a substrate;

17, lower package shielding structure;

19, upper package shielding structure;

51A-51D, planar sensing coils;

53, a flexible substrate;

511 a ferrite core;

55, a signal processing circuit;

c1 and C2 are capacitors;

r1 and R2 are resistors;

v1, a power supply;

l1 is inductance.

Detailed Description

Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.

Fig. 1A-1C are schematic diagrams of a system 1 according to an embodiment of the invention. Referring to fig. 1A-1C, a system 1 includes, but is not limited to, a magnetic field emitter 10 and a magnetic field sensor 50.

In one embodiment, the system 1 may be used for electromagnetic field localization. For example, (S1) a virtual space model of the magnetic field emitter 10 is built according to the origin and the line segment turning points; (S2) feeding a current and measuring the magnetic sensing strength at any point in space to correlate the magnetic field strength with the spatial location; (S3) introducing a magnetic field sensor 50 to establish a correlation of the magnetic field strength with the change in voltage (magnetic flux); (S4) optimizing the transmitting coil magnetic field models of (S1) and (S2); (S5) calculating the position and orientation of the magnetic field sensor 50 (as shown in fig. 1A) by experimental and model magnetic flux least squares error; (S6) establishing a visual three-dimensional environment according to the coordinate information. Thus, the position and posture of the magnetic field sensor 50 can be estimated based on the magnetic flux measured by the magnetic field sensor 50 (as shown in fig. 1B and 1C).

Taking fig. 1C as an example, the magnetic field sensor 50 may be provided on an organ of the person P, and a computer or other controller may control the magnetic field emitter 10 to radiate and measure magnetic flux through the magnetic field sensor 50, and thereby derive a position and/or posture of the organ.

It should be noted that there are many ways to implement electromagnetic field positioning, and embodiments of the present invention are not limited. In addition, other application scenarios are possible for the system 1.

Notably, the magnetic field transmitter 10 comprises one or more transmitting units 11. Each transmitting unit 11 comprises one or more planar transmitting coils. The planar transmitting coil in each transmitting unit 11 is a spiral coil formed by winding a wire (for example, made of copper, aluminum or other conductive material) according to a polygon shape on a plane (for example, a horizontal plane, a vertical plane or an arbitrary plane). The number of sides of the polygon is greater than two. For example triangular, quadrangular or hexagonal. The planar coil is designed to be thin and high-density. Furthermore, this design has a high elasticity and a spatial model of the magnetic field can be easily built.

There are a number of embodiments of planar transmit coils. Fig. 2A is a schematic diagram of a planar transmit coil 11A according to an embodiment of the present invention. Referring to fig. 2A, the planar transmitting coil 11A is a quadrangular helical coil. Fig. 2B is a schematic diagram of a transmitting unit according to another embodiment of the present invention. Referring to fig. 2B, the planar transmitting coil 11B is a hexagonal helical coil. Fig. 2C is a schematic diagram of a transmitting unit according to still another embodiment of the present invention. Referring to fig. 2C, the planar transmitting coil 11C is an octagonal helical coil. It should be noted that, fig. 2A to fig. 2C take regular polygons with the same side length as an example, but the side length may be readjusted (e.g., some or all of the side lengths are different) according to practical requirements.

Referring to fig. 2A-2C, in one embodiment, a maximum outer diameter d1 is assumed _out ,d2 _out ,d3 _out Is the largest polygonal inner diameter formed by the planar transmitting coils 11A-11C, and the smallest inner diameter d1 _in ,d2 _in ,d3 _in Is the inner diameter of the smallest polygon formed by the planar transmit coils 11A-11C. Maximum outer diameter d1 of planar transmitting coils 11A to 11C _out ,d2 _out ,d3 _out Minimum inner diameter d1 _in ,d2 _in ,d3 _in The length ratio of (2) is less than 10. For example, d1 _out Less than 100 millimeters (mm), and d1 _in Greater than 10mm.

In one embodiment, the widths w1, w2, w3 of the wires are between 0.15 mm and 2.5 mm. In one embodiment, the spacing s1, s2, s3 of the wires in the vertical direction is greater than 0.1 mm. I.e. the tracks on the plane do not overlap. The vertical direction of the wire is a direction perpendicular to the wiring direction of the wire. In one embodiment, the angles θ1, θ2, θ3 between adjacent line segments in the polygon are between 90 and 180 degrees.

The number of wire turns in the embodiment of fig. 2A-2C is approximately three. However, in some embodiments, the number of turns around the wire is greater than 12.

In one embodiment, multiple planar transmit coils may be stacked. For example, fig. 3A is a side view of the emission unit 11 according to an embodiment of the present invention, fig. 3B is a perspective view of fig. 3A, and fig. 3C is a top view (length unit is millimeters (mm)) of fig. 3A. Referring to fig. 3A to 3C, the transmitting unit 11 includes four planar transmitting coils 12 stacked two by two. The shape of the two planar transmit coils 12 of the stack is substantially the same. For example, all have regular hexagons. The lower planar transmit coil 12 is almost or completely covered by the upper planar transmit coil 12 in a top view. Furthermore, the spacing in between vertically adjacent two planar transmit coils 12 is approximately 1.5 millimeters. The included angle between adjacent line segments in the quadrangle is 90 degrees. In one embodiment, the thickness th of the conductive line is between 35-70 micrometers (um). On the other hand, the driving current c may be fed from the wire of the planar transmitting coil 12 at an end point near the center.

It should be noted that fig. 3A and 3B take two stacked layers as an example. In some embodiments, the number of layers stacked (equivalent to the number of windings) is 2-16. The number of layers can generate a higher magnetic field strength for the same drive current. However, the number of layers may still be varied according to the actual magnetic field strength requirements. In addition, the inflow (marked with x) and outflow (marked with +) of the driving current c shown in fig. 3A are merely for illustrating that the driving current c may be fed from the wire of the planar transmitting coil 12 at the end near the center. However, the current inlet/outlet lines of the transmitting coil are prevented from penetrating the windings as directly as possible to reduce the nonuniform magnetic field and to avoid affecting the accuracy of the system.

In an embodiment, the bottom side of the lower planar transmitting coil 12 is provided with a shielding structure 13. The shielding structure is composed of a shielding material, such as Mu alloy or manganese zinc Ferrite (MnZn Ferrite). The shielding material has the characteristics of high resistivity and high magnetic permeability, can reduce the secondary distorted magnetic field induced by surrounding ferromagnetic objects due to magnetic induction, and improve the distortion generated by the surrounding environment on the main magnetic field of the magnetic field emitter 10, thereby optimizing the magnetic field intensity of the magnetic field emitter 10. Since the permeability of high permeability alloys is very high, high resistivity can reduce eddy current energy losses.

It should be noted that, a closed eddy sensing current (for example, an eddy current) is generated in the conductor/wire of the planar transmitting coil 12, and the magnetic field generated by the eddy current may distort the main magnetic field, thereby deflecting the magnetic lines of force. The magnetic field generated by the ferromagnetic object (or metal patient bed) below the planar transmit coil 12 is distorted to increase the magnetic field strength, optimize the sensed voltage output, and improve the system signal-to-noise ratio (SNR) and reduce position and orientation errors.

The aforementioned structure-related parameters avoid LC resonance in the operating frequency range and compromise high quality factors. In addition, the parameters related to the structure can avoid uneven corner magnetic field intensity, thereby avoiding bandwidth reduction and response distortion. However, other embodiments may have different parameters or values depending on the actual needs. For example, fig. 4A-4C are schematic diagrams of magnetic field strength distribution according to an embodiment of the present invention. Referring to fig. 4A to 4C, the number of turns around the wire may be different, so as to form different magnetic field intensity distributions. The higher the number of turns, the denser the magnetic field strength distribution.

In one embodiment, the emitting unit 11 is disposed on the substrate by a lamination process. Such as a printed circuit board (Printed Circuit Board, PCB), a flexible printed circuit (Flexible Printed Circuit, FPC), or a Low-Temperature Co-fired Ceramic (LTCC) lamination process.

In an embodiment, the magnetic field transmitter 10 includes a plurality of transmitting units 11 to form a coil array. The coil arrays are arranged on the substrate in a coplanar manner in a lamination process mode, the number of the emitting units 11 is more than 4, and the emitting units are driven individually at different frequencies, so that redundant solving information is obtained and further used for multi-degree-of-freedom position and posture calculation.

For example, fig. 5 is a schematic diagram of a magnetic field transmitter 10B according to an embodiment of the invention. Referring to fig. 5, the magnetic field transmitter 10B includes eight transmitting units Tx1 to Tx8. These transmitting units Tx1 to Tx8 are disposed on the plane of the x-y axis and do not overlap each other. The coil array may facilitate the formation of a uniform magnetic field. The design of the redundant transmitter effectively suppresses noise and compensates errors, and the accuracy of a positioning algorithm can be improved.

Fig. 6 is a schematic diagram illustrating a transmit array according to an embodiment of the invention. Referring to fig. 6, the coordinates of the center point of the left graph are assumed to be (0, 0) in the two-dimensional coordinate system established by the axes x, y. The shortest horizontal distance ax1 of the transmitting units Tx4, tx5 to the center point is 0.686 meters, respectively, and the shortest horizontal distance ax2 of the transmitting units Tx1, tx3, tx6, tx8 to the center point is 0.935 meters, respectively. The shortest vertical distance ay1 of the transmitting units Tx2, tx7 to the center point is 0.686 meters, respectively, and the shortest vertical distance ay2 of the transmitting units Tx1, tx3, tx6, tx8 to the center point is 0.935 meters, respectively.

The substrate 15 has a side length dS1, dS2 of about 30 to 50 cm. The substrate 15 is provided with two placement areas A1, A2 in different directions, wherein the area A2 is the area A1 rotated 45 degrees. The transmitting units Tx1, tx3, tx6, tx8 are disposed in the area A2, and the transmitting units Tx2, tx4, tx5, tx7 are disposed in the area A1. The side lengths dA1, dA2 of the area A1 are approximately 70 mm, and the side lengths dA3, dA4 of the area A2 are approximately 70 mm.

It should be noted that other arrangements of the transmitting units in the antenna array are possible, and embodiments of the present invention are not limited.

In one embodiment, each of the transmitting units Tx1 to Tx8 independently inputs a current (e.g., an alternating current). The currents of the transmitting units Tx 1-Tx 8 are all different in frequency and have frequencies between 1-100 kilohertz (kHz). Thus, a composite homogeneous magnetic field can be generated.

To optimize the magnetic field strength, the coil array may also incorporate shielding packaging. Fig. 7 is a schematic diagram of a magnetic field transmitter 10C according to an embodiment of the invention. Referring to fig. 7, the magnetic field transmitter 10C includes eight transmitting units 11, a substrate 15 for disposing the transmitting units 11, a lower package shielding structure 17, and (optionally) an upper package structure 19. The lower package shielding structure 17 is disposed on the bottom side 15 of the substrate, and the shape and area of the lower package shielding structure 17 are substantially the same as those of the substrate 15. The lower package shielding structure 17 and the upper package structure 19 may be combined, and the emission unit 11 and the substrate 15 may be packaged accordingly.

Fig. 8A-8D are schematic diagrams of magnetic field strength according to an embodiment of the invention. Referring to fig. 8A to 8D, a 30 cm×30 cm substrate is taken as an example, and eight emitting units 11 are disposed on the substrate. These transmitting units 11 are supplied with a current of 0.04 ampere, respectively. Fig. 8A is a graph showing the magnetic field strength at a height of 0.0085 to 0.3 millimeters (mm), and fig. 8B to 8D are graphs showing the magnetic field strength at heights of 0.0085, 0.02 and 0.05, respectively. If the height is higher, the magnetic field intensity is slowed down, so that the whole magnetic field distribution is more uniform. For example, the magnetic field strength of FIG. 8B is approximately 6-8 (amperes (A)/meter (m)), and the magnetic field strength of FIG. 8D is approximately 1-1.52 (A/m).

Fig. 9A to 9D are schematic diagrams of magnetic field strength according to an embodiment of the present invention. Referring to fig. 9A to 9D, a 30 cm×30 cm substrate is taken as an example, and eight transmitting units 11 are disposed on the substrate. These transmitting units 11 are supplied with a current of 0.04 ampere, respectively. Fig. 9A is a graph of the magnetic field strength at a height of 0.1 to 0.3, and fig. 9B to 9D are graphs of the magnetic field strength at a height of 0.1, 0.2 and 0.3, respectively. If the height is higher, the magnetic field intensity is slowed down, so that the whole magnetic field distribution is more uniform. For example, the magnetic field strength of FIG. 9B is about 0.7 (A/m), and the magnetic field strength of FIG. 9D is about 0.12 (A/m). Further, fig. 9E is a schematic diagram of magnetic field strength according to an embodiment of the present invention. Referring to fig. 9A and 9E, fig. 9E shows a distribution of magnetic field intensity at a height of 0.3 to 0.5, so that the magnetic field distribution is uniform as compared with that of fig. 9A.

On the other hand, the magnetic field sensor 50 is aimed at. The magnetic field sensor 50 comprises a sensing unit (comprising one or more planar sensing coils). Fig. 10A is a schematic diagram of a planar sensing coil 51A according to an embodiment of the present invention, fig. 10B is a schematic diagram of a planar sensing coil 51B according to another embodiment of the present invention, and fig. 10C is a schematic diagram of a planar sensing coil 51C according to yet another embodiment of the present invention. Similar to fig. 2A-2C, planar sense coils 51A-51C are spiral coils formed by wires (e.g., of copper, aluminum, or other conductive material) encircling according to a geometry in a plane (e.g., horizontal, vertical, or any plane). In these embodiments, the geometry is a polygon and the number of sides of the polygon is greater than two. For example, quadrilateral, hexagonal or octagonal. That is, the planar sensing coil 51A is a quadrangular spiral coil, the planar sensing coil 51B is a hexagonal spiral coil, and the planar sensing coil 51C is an octagonal spiral coil.

In one embodiment, the geometry is circular. FIG. 10D is a schematic diagram of a planar sense coil 51D according to yet another embodiment of the present invention. Referring to fig. 10D, the difference from fig. 10A to 10C is that the geometry of the planar sensing coil 51D is circular.

Referring to fig. 10A to 10D, in one embodiment, a maximum outer diameter D4 is assumed _out ,d5 _out ,d6 _out ,d7 _out Is the outer diameter of the largest geometry formed by the planar sense coils 51A-51D, and the smallest inner diameter D4 _in ,d5 _in ,d6 _in ,d7 _in Is the inner diameter of the smallest geometry formed by the planar sense coils 51A-51D. In one embodiment, the maximum outer diameter D4 of the planar sense coils 51A-51D _out ,d5 _out ,d6 _out ,d7 _out Less than 30 mm. In one embodiment, the minimum inner diameter d4 _in ,d5 _in ,d6 _in ,d7 _in Less than 1 mm.

In one embodiment, the widths w4, w5, w6, w7 of the wires are between about 0.15 mm. In one embodiment, the spacing s4, s5, s6, s7 of the wires in the vertical direction is greater than 0.1 mm. I.e. the tracks on the plane do not overlap. The vertical direction of the wire is a direction perpendicular to the wiring direction of the wire. In one embodiment, the angles θ5, θ6, θ7 between adjacent line segments in the polygon are between 90 and 180 degrees.

The number of wire turns in the embodiment shown in fig. 10A-10D is approximately three. However, in some embodiments, the number of turns around the wire is greater than 12.

In one embodiment, the sensing unit includes a plurality of stacked planar sensing coils, and the stacked planar sensing coils can refer to fig. 3A and 3B. The lower planar sense coil is almost or completely covered by the upper planar sense coil in a top view. Furthermore, the distance between two vertically adjacent planar sensing coils is less than 1.5 mm. In one embodiment, the wire has a thickness between 35-70 micrometers (um).

It should be noted that in some embodiments, the number of layers of stacked planar sensing coils is 2-16, but may be changed according to practical requirements.

FIG. 11 is a schematic diagram of a magnetic field sensor according to an embodiment of the invention. Referring to fig. 11, in one embodiment, the sensing unit 51D of the magnetic field sensor is disposed on the flexible substrate 53 by a lamination process. For example PCB, FPC, LTCC. The flexible substrate 53 is, for example, a PI film or made of a polymer material compatible with the living things, so as to be suitable for being adhered to a body surface or an organ in a body. In one embodiment, the wire has a ferrite core 511 embedded therein. Ferrite core 511 has a high permeability characteristic that optimizes the sense voltage output, thereby improving the system signal-to-noise ratio and reducing position and orientation errors.

The sensing unit 51D is connected to the signal processing circuit 55. The signal processing circuit 55 is, for example, an RC circuit. Fig. 12A is an equivalent circuit diagram of the signal processing circuit 55 according to an embodiment of the present invention. Referring to fig. 12A, in the circuit, capacitors C1 and C2 are connected in parallel, the capacitor C2 is connected in series with a resistor R2, and the capacitors C1 and C2 connected in parallel are connected in series with a power source V1, a resistor R1 and an inductor L1. The capacitance value of the parallel capacitors C1, C2 is 0.05uF. Fig. 12B is a frequency response diagram according to an embodiment of the invention. Referring to fig. 12B, LC resonance can be suppressed and the control band can be increased by the capacitor C2 connected in series and the resistor R2 connected in series.

Through experimental tests, the magnetic field emitter and the magnetic field sensor of the embodiment of the invention have lower alternating current impedance at 19.7-32.2 kilohertz, and can ignore parasitic capacitance effect between low-frequency coils.

In summary, in the magnetic field emitter and the magnetic field sensor according to the embodiments of the present invention, the planar spiral coil is formed into the three-dimensional space coil structure by the lamination process, so as to achieve miniaturization, thinning and high density of the circuit. At the transmitting end, a coplanar transmitting coil array is formed and driven with alternating currents of different frequencies. In addition, the bottom side of the transmitting unit is combined with the shielding structure, so that the secondary distortion magnetic field of surrounding ferromagnetic objects caused by magnetism induction is reduced, and the magnetic field generated by the transmitter due to influence of the surrounding environment is further improved. At the sensing end, by stacking coils in series to add inductance, conductor traces do not overlap to minimize winding parasitic capacitance and improve sensing sensitivity by embedded ferrite cores. The magnetic field emitter and the magnetic field sensor provided by the embodiment of the invention are applied to electromagnetic positioning technology, and can solve the limitation of the infrared positioning system technology in vivo positioning application. For example, soft tissue/organ shielding is limiting and is not fully integrated with minimally invasive instruments. In addition, the embodiment of the invention can compensate the respiratory and cardiac rhythm positioning errors of the patient, improve the magnetic field distortion and reduce the risk in operation.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (12)

1. A magnetic field transmitter, comprising:

at least one transmitting unit comprising:

the planar transmitting coil is a spiral coil formed by winding a wire on a plane according to a polygon, wherein the number of sides of the polygon is more than two.

2. The magnetic field transmitter of claim 1 wherein the ratio of the length of the maximum outer diameter to the minimum inner diameter of the planar transmit coil is less than 10, the maximum outer diameter is the outer diameter of the largest polygon formed by the planar transmit coil, the minimum inner diameter is the inner diameter of the smallest polygon formed by the planar transmit coil, the width of the wire is between 0.15 and 2.5 mm, the spacing of the wire in the vertical direction is greater than 0.1 mm, the thickness of the wire is between 35 and 70 microns, and the number of turns around the wire is greater than 12.

3. The magnetic field transmitter of claim 1 wherein the transmitting unit comprises a stack of a plurality of the planar transmitting coils, and wherein the spacing between adjacent planar transmitting coils is about 1.5 mm.

4. The magnetic field transmitter of claim 1 wherein the at least one transmitting unit comprises a plurality of transmitting units to form a coil array, wherein the coil array is provided on the substrate in a lamination process, and the number of transmitting units is greater than 4.

5. The magnetic field transmitter of claim 4 wherein each of said transmitting units independently inputs a current, said currents of said transmitting units being of different frequencies and having frequencies between 1 khz and 100 khz.

6. The magnetic field transmitter of claim 4, wherein the at least one transmitting unit further comprises:

the shielding structure is arranged at the bottom side of the substrate and is made of shielding materials.

7. A magnetic field sensor, comprising:

a sensing unit comprising:

a planar sensing coil is a spiral coil formed by a wire wound around a plane according to a geometric shape, wherein the wires on the plane are not overlapped.

8. The magnetic field sensor of claim 7, wherein the maximum outer diameter of the planar sense coil is less than 30 millimeters, the maximum outer diameter is the outer diameter of the maximum geometry formed by the planar sense coil, the minimum inner diameter of the planar sense coil is less than 1 millimeter, the minimum inner diameter is the inner diameter of the minimum geometry formed by the planar sense coil, the width of the wire is about 0.15 millimeter, the spacing of the wire in the vertical direction is greater than 0.1 millimeter, the thickness of the wire is between 35 and 70 microns, and the number of turns around the wire is greater than 12.

9. The magnetic field sensor of claim 7, wherein the geometric shape is a polygon and the number of sides of the polygon is greater than two.

10. The magnetic field sensor of claim 7, wherein the sensing unit comprises a plurality of stacked planar sensing coils, and a spacing between two adjacent planar sensing coils is less than 1.5 mm.

11. The magnetic field sensor of claim 7, wherein the wire has a ferrite core embedded therein.

12. The magnetic field sensor of claim 7, wherein the sensing unit is disposed on the flexible substrate by a lamination process.

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