TWI437249B - Magnetic sensor apparatus - Google Patents

Description

Magnetic sensing device

The present disclosure relates to a magnetic sensing device, and more particularly to a coil structure design for a magnetoresistive sensing device.

Magnetoresistance effect (MR) refers to the effect of the resistance of a specific magnetoresistive material changing with the applied magnetic field. Due to the above characteristics, magnetoresistive materials are generally used in various magnetic or magnetic field sensing devices, such as solid state compassing, metal detection, and position detection.

At present, devices for magnetic sensing using magnetoresistive materials are more common, such as Giant Magnetoresistance (GMR) magnetic sensors and Anisotropic Magnetoresistance (AMR) magnetic sensors.

The giant magnetoresistance effect exists in a multilayer film system formed by ferromagnetism (eg, Fe, Co, Ni) and non-ferromagnetic (eg, Cr, Cu, Ag, Au) due to the need for giant magnetoresistance (GMR) sensors. A multilayer film structure in which ferromagnetic and non-ferromagnetic materials are alternately disposed is complicated in manufacturing.

The anisotropic magnetoresistance effect exists on ferromagnetic (eg, Fe, Co, Ni) materials and their alloy blocks or films. The amount of change in magnetoresistance of an anisotropic magnetoresistive (AMR) sensor is related to the operating current passed through the anisotropic magnetoresistive material.

The magnetoresistive material in the magnetoresistive sensor has a magnetization direction, and the magnetization direction of each magnetoresistive material will change correspondingly with the change of the surrounding magnetic field. Therefore, under different environmental conditions, the respective magnetoresistive materials The initial magnetization direction will be different.

On the other hand, temperature changes may also cause sensitivity deviations in the magnetic sensing of the magnetoresistive sensor. The magnetoresistive sensor is presented with different sensing results under high temperature and low temperature operation. As a result, the output of the magnetoresistive sensor will be distorted.

The temperature drift of the sensor can be compensated by establishing a forward and reverse reset magnetic field for the magnetoresistive sensor by a specific coil and comparing the sensor output results under the forward and reverse reset magnetic fields. However, only about half of the line segments of the conventional compensation coil are used to establish the same magnetic field, and the area utilization efficiency is only about 50%, so that the compensation coil takes up unnecessary space. In addition, the conventional compensation coil is of a single spiral type and has a large size in the width direction, so that the compensation coil takes up unnecessary space.

In order to solve the above problems, the present invention discloses a magnetic sensing device including a plurality of magnetoresistive sensing units, a compensation coil, and a reset coil. The compensation coil is used to introduce a compensation current to establish a compensation magnetic field to correct the sensitivity deviation at different temperatures. The reset coil is used to introduce a reset current to establish a reset magnetic field, thereby resetting the magnetization direction of the magnetoresistive sensing unit before the sensing, so that the magnetization direction of the magnetoresistive sensing unit is uniform, thereby ensuring the magnetic sense Sensing accuracy of the measuring device. In addition, the line configuration of the compensation coil of the present case has a double helix structure opposite to each other, whereby the width occupied by the compensation coil can be minimized, and the compensation current has the same current flow direction when passing through the vicinity of the magnetoresistive sensing unit.

One aspect of the present disclosure is to provide a magnetic sensing device including a substrate, a plurality of magnetoresistive sensing units, a reset coil, and a compensation coil. The magnetoresistive sensing units are respectively disposed on the substrate. The reset coil is disposed above the magnetoresistive sensing unit, and the reset coil is used to introduce a reset current. The compensation coil is disposed above the magnetoresistive sensing unit, and the compensation coil is configured to introduce a compensation current. The circuit configuration of the compensation coil includes a first spiral portion and a second spiral portion opposite to each other.

According to an embodiment of the present invention, the compensation coil includes a plurality of main line segments and a plurality of connecting line segments, wherein the main line segments are arranged in parallel and have a gap between each other, wherein each connecting line segment is connected to two of the main line segments Between adjacent end points, and connecting the main line segments and the connecting line segments in the compensation coil to the first spiral portion and the second spiral portion.

According to an embodiment of the present invention, the arrangement direction of the main line segments is parallel to the arrangement direction of the magnetoresistive sensing units.

According to an embodiment of the present invention, the connection direction of the connecting line segments is perpendicular to the arrangement direction of the magnetoresistive sensing units.

According to an embodiment of the present invention, at least a portion of the main line segments of the main line segments cover the magnetoresistive sensing units.

According to an embodiment of the present invention, when the compensation current passes over the at least a portion of the main line segments of the magnetoresistive sensing unit, the compensation current has the same current flow direction on the at least a portion of the main line segments. .

According to an embodiment of the invention, the first spiral portion is a clockwise spiral, and the second spiral portion is a counterclockwise spiral.

According to an embodiment of the invention, the first spiral portion is a counterclockwise spiral and the second spiral portion is a clockwise spiral.

According to an embodiment of the present invention, each of the magnetoresistive sensing elements is an elongated strip, and each of the two magnetoresistive sensing elements has an acute angle tip.

According to an embodiment of the present invention, the magnetic sensing device is an anisotropic magnetoresistance (AMR) sensing device, and the magnetoresistive sensing units respectively comprise an anisotropic magnetoresistive material.

Please refer to FIG. 1 , which is a top plan view of a magnetic sensing device 100 according to an embodiment of the invention. As shown in FIG. 1, the magnetic sensing device 100 includes at least a substrate 120, a plurality of magnetoresistive sensing units 140a, 140b, a compensation coil 160, and a reset coil 180.

In practical applications, the magnetic sensing device 100 may further include an input/output interface end point (not shown) and a corresponding connection line (not shown) for introducing a current or voltage signal into the magnetoresistive sensing unit 140a. Among the 140b, the compensation coil 160 and the reset coil 180, since the arrangement of the interface end points and the connection lines is well known to those skilled in the art, no further details are provided herein.

Please refer to FIG. 2 together, which shows a schematic diagram of the separation of the magnetoresistive sensing units 140a, 140b in FIG. As shown in FIG. 1 and FIG. 2, the magnetic sensing device 100 of the present embodiment includes a plurality of magnetoresistive sensing units 140a, 140b respectively disposed on the substrate 120. In this embodiment, the magnetic sensing device 100 has a total of sixteen sets of magnetoresistive sensing units 140a, 140b, but the present invention is not limited to this particular number of magnetoresistive sensing units 140a, 140b. In practical applications, the magnetic resistance The number of sensing units 140a, 140b can be ordered based on actual magnetic sensing requirements. As shown in FIG. 2, each of the magnetoresistive sensing units 140a, 140b is elongated, and the two ends of the magnetoresistive sensing elements 140a, 140b are acute angle tips, respectively.

Since the two ends of the conventional magnetoresistive sensing element are square ends, the two end lines are more easily polarized to form a static magnetic field, and this static magnetic field will lower the sensitivity of the magnetoresistive sensing element. The two ends of the magnetoresistive sensing elements 140a, 140b in the present case are sharp-pointed ends, respectively, thereby reducing the occurrence of polarization on the end lines and avoiding the occurrence of the above-described static magnetic field.

In this embodiment, the magnetic sensing device 100 may be an anisotropic magnetoresistance (AMR) sensing device, and the magnetoresistive sensing units 140a, 140b may respectively comprise an anisotropic magnetoresistive material. The resistance values of the magnetoresistive sensing units 140a, 140b will vary with the magnetic field applied thereto, and therefore, the magnetic sensing device 100 can be used to sense the surrounding magnetic field through the magnetoresistive sensing units 140a, 140b.

Please refer to FIG. 3 together, which shows a schematic diagram of the separation of the compensation coil 160 in FIG. 1 . As shown in FIG. 1 and FIG. 3, in the present embodiment, the compensation coil 160 is disposed above the magnetoresistive sensing units 140a, 140b, and at least a portion of the compensation coil 160 covers the magnetoresistive sensing unit 140a. 140b. The compensation coil 160 is used to introduce a compensation current 162 (as shown in FIG. 3). A compensation current 162 flows through the compensation coil 160 for establishing a compensation magnetic field to the magnetoresistive sensing units 140a, 140b. This compensation magnetic field can be used to correct the influence of the external disturbance magnetic field on the magnetoresistive sensing units 140a, 140b, and the effect of the correction can be controlled by the magnitude of the current of the compensation current 162.

Please refer to FIG. 4 together, which shows a schematic diagram of the separation of the compensation coil 160 in FIG. 1 . As shown in Fig. 4, the line configuration of the compensation coil 160 includes a first spiral portion 160a and a second spiral portion 160b which are opposite to each other.

As shown in FIG. 4, the compensation coil 160 includes a plurality of main line segments 164, 165 and a plurality of connecting line segments 166, wherein the main line segments 164, 165 are arranged in parallel and have a gap therebetween, wherein each connecting line segment 166 is connected to two of them. Between adjacent end points of the main line segments 164, 165, the main line segments 164, 165 and the connecting line segments 166 in the reset coil are connected as a first spiral portion 160a and a second spiral portion 160b.

As shown in FIGS. 3 and 4, in this embodiment, the arrangement direction of the main line segments 164, 165 is parallel to the arrangement direction of the magnetoresistive sensing units 140a, 140b. The arrangement direction of the connection line segments 166 is perpendicular to the arrangement direction of the magnetoresistive sensing units 140a, 140b.

As shown in FIGS. 3 and 4, among the main line segments 164, 165, a portion of the main line segments (i.e., the main line segment 164 in FIG. 4) covers the magnetoresistive sensing units 140a, 140b.

In accordance with an embodiment of the present invention, the compensation current 162 has the same current flow direction on the main line segment 164 when the compensation current 162 passes over a portion of the main line segment 164 that covers the magnetoresistive sensing units 140a, 140b.

It should be particularly noted that in the present embodiment, the compensation coil 160 has a double helix structure, the first spiral portion 160a of the left half of the compensation coil 160 is a clockwise spiral, and the second spiral portion 160b of the right half is a counterclockwise spiral. However, the present invention is not limited thereto. In another embodiment, the spiral directions of the first spiral portion and the second spiral portion may also be interchanged.

With the reverse double helix design, and in conjunction with the arrangement relationship of the compensation coil 160 and the magnetoresistive sensing units 140a, 140b in this case, in this example, the compensation currents 162 above the magnetoresistive sensing units 140a, 140b are With the same current flow direction, as in the embodiment of Fig. 3, the compensation current 162 passing through the magnetoresistive sensing units 140a, 140b flows from top to bottom. Thereby, the compensation current 162 can establish a compensating magnetic field in the same direction to all of the magnetoresistive sensing units 140a, 140b. In addition, the compensation coil 160 of the reverse double helix design in the present case can save the coil width and the overall area, thereby improving the area use efficiency of the magnetic sensing device 100.

It should be noted that, in the above embodiment, the compensation current 162 passing through the magnetoresistive sensing units 140a, 140b flows from top to bottom, but the invention is not limited thereto, and the reverse compensation current is also used. A similar effect can be achieved, depending on the direction of the magnetic field to be compensated for in the actual circuit requirements.

Please refer to FIG. 5 and FIG. 6 together, which shows a schematic diagram of the separation of the reset coil 180 in FIG. 1 . As shown in FIG. 5, the reset coil 180 is used to introduce a reset current 182. At least a portion of the reset coil 180 covers the magnetoresistive sensing units 140a, 140b, and the reset current 182 is used to reset the reluctance. Sensing units 140a, 140b.

As shown in Fig. 6, the reset coil 180 is a spiral coil. The spiral coil of the reset coil 180 can be a clockwise spiral or a counterclockwise spiral. In the embodiment, a clockwise spiral is illustrated, but the invention is not limited thereto.

Based on the characteristics of the magnetoresistive material, each of the magnetoresistive sensing units 140a, 140b includes a plurality of magnetic domains, each of which has a magnetization direction. As shown in FIG. 5, for the eight sets of magnetoresistive sensing units 140a located above the illustration, the reset current 182 flowing through the reset coil 180 has a current flow from left to right, and the reset current 182 can be used. A resetting magnetic field is established to reset the magnetization direction of each magnetic domain in the magnetoresistive sensing unit 140a, so that the magnetization direction of the magnetoresistive sensing unit 140a is reset to the same magnetization direction.

On the other hand, for the eight sets of magnetoresistive sensing units 140b located below the illustration, the reset current 182 flowing through the reset coil 180 has a right-to-left current flow direction, at which time the reset current 182 can be used. Another reset magnetic field is established to reset the magnetization direction of each magnetic domain in the magnetoresistive sensing unit 140b, so that the magnetization direction of the magnetoresistive sensing unit 140b is reset to the same other magnetization direction.

Thereby, the magnetoresistive sensing unit 140a and the magnetoresistive sensing unit 140b can respectively have a uniform magnetization direction after being reset. Thereby, resetting is performed before each sensing is performed, or resetting is periodically performed to ensure that the magnetoresistive sensing unit 140a and the magnetoresistive sensing unit 140b each have a uniform magnetization direction, thereby ensuring magnetic The sensing accuracy of the sensing device is important in high precision compass systems or high sensitivity precision devices.

Further, as shown in FIGS. 5 and 6 , the line segment width of the main line segment 184 in the reset coil 180 is wider, and the main line segment 184 of the reset coil 180 is larger than the line segment width of the connection line segment 186 of the reset coil 180.

During the actual current flow, the reset current 182 will progress toward the flow path of the shorter path. That is to say, on a general spiral reset coil, the reset current will flow along the inner side of the reset coil near the center of the spiral, so that the reset current cannot be evenly distributed over the reset coil. On each line segment, it is concentrated on the inner side of the reset coil. In particular, the main line segment 184 of the reset coil 180 has a wider width and the effect is more pronounced.

Accordingly, the reset coil 180 of the present invention has a plurality of notch structures 188 that are respectively located at the turns of the reset coil 180. As shown in Fig. 6, each of the main line segments 184 has an inner side 184a and an outer side 184b. The inner side 184a is adjacent to the center of the helical reset coil 180. As shown, the notch structure 188 at the turn of the reset coil 180 is disposed on the inner side edge 184a of the main line segment 184.

With the design of the notch structure 188 described above, it is avoided that the reset current 182 is excessively concentrated on the inner side edge 184a of the main line segment 184 such that the reset current 182 is more evenly distributed on the reset coil 180.

In an actual application, the magnetoresistive sensing unit 140, the compensation coil 160, and the reset coil 180 may be respectively disposed on the substrate 120, and the arrangement of the films in the above embodiments of the present invention is merely an illustrative description. The magnetoresistive sensing unit 140, the compensation coil 160, and the reset coil 180 are not limited to be arranged at a specific upper and lower position.

In summary, the magnetic sensing device of the present invention includes a plurality of magnetoresistive sensing units, a compensation coil, and a reset coil. The compensation coil is used to introduce a compensation current to establish a compensation magnetic field to correct the deviation of the magnetoresistive sensor output due to the external interference magnetic field. The reset coil is used to introduce a reset current to establish a reset magnetic field, thereby resetting the magnetization direction of the magnetoresistive sensing unit before the sensing, so that the magnetization direction of the magnetoresistive sensing unit is uniform, thereby ensuring the magnetic sense Sensing accuracy of the measuring device. Also, the temperature drift of the magnetoresistive sensor can be corrected by comparing the sensor output results in the forward and reverse reset magnetic fields. In addition, the line configuration of the compensation coil of the present case has a double helix structure opposite to each other, whereby the width occupied by the compensation coil can be minimized, and the compensation current has the same current flow direction when passing through the vicinity of the magnetoresistive sensing unit.

The present disclosure has been disclosed in the above embodiments, but it is not intended to limit the disclosure, and any person skilled in the art can make various changes and refinements without departing from the spirit and scope of the disclosure. The scope of protection of the disclosure is subject to the definition of the scope of the patent application.

100. . . Magnetic sensing device

120. . . Substrate

140a, 140b‧‧‧Magnetoresistive Sensing Unit

160‧‧‧Compensation coil

160a‧‧‧first spiral part

160b‧‧‧second spiral part

162‧‧‧Compensation current

164‧‧‧ main line segments

165‧‧‧ main line segments

166‧‧‧Connected line segments

180‧‧‧Reset coil

182‧‧‧Reset current

184‧‧‧ main line segments

186‧‧‧Connected line segments

184a‧‧‧ inside side

184b‧‧‧ outside side

188‧‧ ‧ gap structure

The above and other objects, features, advantages and embodiments of the present disclosure will become more apparent and understood.

1 is a top plan view of a magnetic sensing device according to an embodiment of the invention;

2 is a schematic view showing the separation of the magnetoresistive sensing unit in FIG. 1;

Figure 3 is a schematic view showing the separation of the compensation coil in Figure 1;

Figure 4 is a schematic view showing the separation of the compensation coil in Figure 1;

Figure 5 is a schematic view showing the separation of the reset coil in Figure 1;

Fig. 6 is a schematic view showing the separation of the reset coil in Fig. 1.

160‧‧‧Compensation coil

160a‧‧‧first spiral part

160b‧‧‧second spiral part

164‧‧‧ main line segments

165‧‧‧ main line segments

166‧‧‧Connected line segments

Claims (10)

A magnetic sensing device includes: a substrate; a plurality of magnetoresistive sensing units respectively disposed on the substrate; a reset coil disposed above the magnetoresistive sensing unit, the reset coil is used to introduce a And a compensation coil is disposed above the magnetoresistive sensing unit, the compensation coil is configured to introduce a compensation current, and the circuit configuration of the compensation coil includes a first spiral portion and a second spiral portion The compensation current flows through the first spiral portion and the second spiral portion, wherein the path of the compensation current flowing through the first spiral portion and the path flowing through the second spiral portion have opposite spiral directions . The magnetic sensing device of claim 1, wherein the compensation coil comprises a plurality of main line segments and a plurality of connecting line segments, wherein the main line segments are arranged in parallel and have a gap between each other, wherein each connecting segment is connected Between adjacent end points of the two main line segments, and connecting the main line segments and the connecting line segments in the compensation coil to the first spiral portion and the second spiral portion. The magnetic sensing device of claim 2, wherein the main The arrangement direction of the line segments is parallel to the arrangement direction of the magnetoresistive sensing units. The magnetic sensing device of claim 2, wherein the connecting line segments are arranged in a direction perpendicular to a direction in which the magnetoresistive sensing units are disposed. The magnetic sensing device of claim 2, wherein at least a portion of the main line segments of the main line segments cover the magnetoresistive sensing units. The magnetic sensing device of claim 5, wherein the compensation current is in the at least a portion of the main line segment when the compensation current passes through the at least a portion of the main line segment of the magnetoresistive sensing unit It has the same current flow direction. The magnetic sensing device of claim 1, wherein the path of the first spiral portion relative to the compensation current is a clockwise spiral, and the path of the second spiral portion relative to the compensation current is one Counterclockwise spiral. The magnetic sensing device of claim 1, wherein the first spiral portion is a counterclockwise spiral, and the second spiral portion is a clockwise Needle spiral. The magnetic sensing device of claim 1, wherein each of the magnetoresistive sensing elements has a strip shape, and each of the two magnetoresistive sensing elements has an acute angle tip. The magnetic sensing device of claim 1, wherein the magnetic sensing device is an anisotropic magnetoresistance (AMR) sensing device, and the magnetoresistive sensing units respectively comprise a different Directional magnetoresistive material.