TW201318237A - Magnetic sensor apparatus - Google Patents

Abstract

The invention discloses a magnetic sensor apparatus, which includes a substrate, a plurality of magnetoresistance sensor units, a compensation coil and a reset coil. The magnetoresistance sensor units are disposed on the substrate. The compensation coil is disposed over the magnetoresistance sensor units. The compensation coil is used for importing a compensating current. The reset coil is disposed over the magnetoresistance sensor units. The reset coil is used for importing a resetting current. The resetting current is used for resetting the magnetoresistance sensor units. The reset coil has a plurality of breaches located at bending portions of the reset coil.

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.

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 reset coil of the present invention further has a plurality of notch structures located at the turning point of the reset coil, thereby ensuring that the reset current is evenly distributed when flowing through the reset coil, thereby avoiding excessive resetting of the reset current to the heavy Place the same side of each line segment in the coil.

One aspect of the present disclosure is to provide a magnetic sensing device including a substrate, a plurality of magnetoresistive sensing units, a compensation coil, and a reset coil. A plurality of magnetoresistive sensing units are respectively disposed on the substrate. The compensation coil is disposed above the magnetoresistive sensing unit, and the compensation coil is used to introduce a compensation current. The reset coil is disposed above the magnetoresistive sensing unit, and the reset coil is configured to introduce a reset current for resetting the magnetoresistive sensing unit, wherein the reset coil has a plurality of gaps The structure is located at the turning point of the reset coil.

According to an embodiment of the present disclosure, the reset 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 lines Between adjacent end points of the line segment, and connecting the main line segments and the connecting line segments in the reset coil to a spiral coil.

In accordance with an embodiment of the present disclosure, the helical coil is a clockwise spiral or a counterclockwise spiral.

In accordance with an embodiment of the present disclosure, wherein the reset current flows through the helical reset coil, a reset magnetic field is established to reset the magnetoresistive sensing unit.

According to an embodiment of the present disclosure, the turning point where the notch structures are located is the boundary between the main line segments and the connecting line segments.

According to an embodiment of the present disclosure, each of the main line segments has an inner side edge and a opposite outer side side adjacent to a center of the spiral coil, and the notch structures are disposed on an inner side of the main line segments on. In practical applications, the gap structures can be used to avoid excessive concentration of the reset current on the inner side edges of the main line segments.

According to an embodiment of the present disclosure, the line segment width of the main line segments is greater than the line segment width of the connecting line segments.

According to an embodiment of the present disclosure, 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 disclosure, 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 influence the influence of the ambient temperature change 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.

It should be particularly noted that in the present embodiment, the compensation coil 160 has a double helix structure, the left half of the compensation coil 160 is a clockwise spiral, and the right half is a counterclockwise spiral. 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. 4 and FIG. 5 together, which shows a schematic diagram of the separation of the reset coil 180 in FIG. 1 . As shown in FIG. 4, 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. 5, the reset coil 180 includes a plurality of main line segments 184 and a plurality of connecting line segments 186, wherein the main line segments 184 are arranged in parallel and have a gap therebetween, wherein the connecting line segments 186 are connected to the two main line segments 184. Between adjacent end points, the main line segment 184 and the connecting line segment 186 in the reset coil 180 are connected as a spiral coil. The spiral coil may be a clockwise spiral or a counterclockwise spiral. In this 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. 4, 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. 4 and 5, the line segment 184 of the reset coil 180 has a wider line segment width, and the main line segment 184 is larger than the line segment width of the connecting line segment 186.

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 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. 5, 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, and the outer side 184b is opposite the inner side 184a. As shown, the notch structure 188 at the turn of the reset coil 180 is located at the junction of the main line segment 184 and the connecting line segment 186, and the notch structure 188 is disposed on the inner side edge 184a of the main line segment 184.

As shown in FIG. 5, in the present embodiment, each set of notch structures 188 on the reset coil 180 may include a tapered notch 188a and an adjacent slit 188b, wherein the direction of the slit 188b may be substantially Parallel to one of the sides of the tapered corner 188a. In this embodiment, the notch structure 188 includes the tapered corner 188a and the slit 188b, but the invention is not limited thereto. In another embodiment, the notch structure 188 may only include the inner side. The lack of corners, or the equivalence gaps of various shapes on the inside side, are considered to be within the scope of the present invention.

Referring to FIGS. 4 and 5, the design of the notch structure 188 prevents the reset current 182 from being excessively concentrated on the inner side 184a of the main line segment 184. When the reset current 182 flows through the turning point of the reset coil 180, the tapered chamfer 188a and the slit 188b will distribute the reset current 182 on the reset coil 180 more evenly at various positions of the coil. As shown in the schematic diagram of FIG. 5, the flow path of the reset current 182 on the reset coil 180 may be substantially distributed to the inner, center, and outer sides of the reset coil 180. In Fig. 4, for the sake of simplicity of the drawing, the distribution of the current path is only shown at the turning point of the innermost circle of the reset coil 180, and in fact, the notch structure 188 at each turn of the reset coil 180 can be similar. effect.

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 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 reset coil of the present invention further has a plurality of notch structures located at the turning point of the reset coil, thereby ensuring that the reset current is evenly distributed when flowing through the reset coil, thereby avoiding excessive resetting of the reset current to the heavy Place the same side of each line segment in the coil.

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

162. . . Compensation current

180. . . Reset coil

182. . . Reset current

184. . . Main line segment

186. . . Connecting line segment

184a. . . Medial side

184b. . . Outer side

188. . . Gap structure

188a. . . Tapered corner

188b. . . Slit

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 reset coil in Figure 1;

Fig. 5 is a schematic view showing the separation of the reset coil in Fig. 1.

140a, 140b. . . Magnetoresistive sensing unit

180. . . Reset coil

182. . . Reset current

188. . . Gap structure

Claims (10)

A magnetic sensing device comprises: a substrate; a plurality of magnetoresistive sensing units respectively disposed on the substrate; a compensation coil disposed above the magnetoresistive sensing unit, the compensation coil is configured to introduce a compensation current And a reset coil disposed above the magnetoresistive sensing unit, the reset coil is configured to introduce a reset current for resetting the magnetoresistive sensing unit, the reset coil A plurality of notch structures are located at the corners of the reset coil. The magnetic sensing device of claim 1, wherein the reset 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 line segment Connected between adjacent end points of the two main line segments, and connect the main line segments in the reset coil and the connecting line segments into a spiral coil. The magnetic sensing device of claim 2, wherein the spiral coil is a clockwise spiral or a counterclockwise spiral. The magnetic sensing device of claim 2, wherein when the reset current flows through the spiral reset coil, a reset magnetic field is established to reset the magnetoresistive sensing unit. The magnetic sensing device of claim 2, wherein the turning point where the notch structure is located is the boundary between the main line segments and the connecting line segments. The magnetic sensing device of claim 2, wherein each of the main line segments has an inner side edge and a opposite outer side side adjacent to a center of the spiral coil, and the notch structures are disposed on the same On the inside side of the main line segment. The magnetic sensing device of claim 6, wherein the notch structures are used to prevent the reset current from being excessively concentrated on the inner side edges of the main line segments. The magnetic sensing device of claim 2, wherein the line segment width of the main line segments is greater than the line segment width of the connecting line segments. 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.