JP2008216181A - Azimuth sensor and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor element having equal sensitivity without a degradation of sensitivity in X-, Y-, Z-directions while being small in size and height and an azimuth sensor mountable on a mobile information terminal in which three magnetic sensor elements are disposed orthogonal to each other. <P>SOLUTION: In this azimuth sensor, first to third magnetic sensors disposed on the X-, Y-, and Z-axes, respectively, for detection magnetic fields are disposed on a flat substrate. The first magnetic sensor is so disposed that the detection axis of the magnetic sensor is positioned parallel to the surface of the flat substrate. The second magnetic sensor is disposed on a first flat surface, at a predetermined angle θ relative to the flat substrate. The third magnetic sensor is disposed on a second flat surface at an angle (90°-θ) relative to the flat substrate and at an angle of 90° relative to the first flat surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic sensor element, an azimuth sensor having the magnetic sensor element, and an electronic azimuth meter equipped with the azimuth sensor, and can be mounted on a portable information terminal even if three magnetic sensor elements are arranged orthogonally. The present invention relates to a small azimuth sensor and an electronic device equipped with the azimuth sensor.

  The direction sensor is configured by arranging a plurality of perpendicularly arranged magnetic sensor elements. Then, by calculating data based on magnetic sensor outputs from a plurality of magnetic sensor elements arranged orthogonally, an angle from a direction determined as a reference, that is, an azimuth angle can be calculated. Since the azimuth obtained from this azimuth can be processed as an analog or digital electrical signal, a portable information terminal such as a mobile phone or PDA, a wristwatch, a car navigation device as a vehicle azimuth meter, an attitude detection of an aircraft, a visually impaired person Application to various electronic devices such as a game machine is expected.

  In particular, in recent years, position information providing services for portable information terminals using GPS or the like have begun. According to this service, the user can understand the current position information while looking at the screen on the terminal. By combining this terminal with an electronic compass, it is possible to determine which direction the user is currently facing, or where he is going if he is walking. This information providing service regarding position information and electronic compass is expected to create new business for many industries in the future, and will also provide useful information to users.

  On the other hand, the above-described portable information terminal tends to be small and thin, and an electronic device mounted in the portable information terminal is required to be small and low-profile. The width of the magnetic sensor element desired here is about several millimeters, and the height is particularly required to be 1.5 mm or less, and preferably a size of 1.0 mm or less is required.

  In order to solve such a problem, an orientation sensor equipped with a triaxial magnetic sensor element that can be reduced in size has been proposed (for example, see Patent Document 1).

In this conventional azimuth sensor, the first and second magnetic sensor elements functioning as two magnetoresistive effect elements on the nonmagnetic base and the third magnetic sensor functioning similarly as the magnetoresistive element on the inclined base are provided. Each sensor element is provided. This tilting table is formed of an insulating film such as SiO _2. After forming a plate-like substrate having a thickness of 20 μm in the thickness direction of the tilting table, etching is performed by RIE (reactive ion etching) or the like. Formed. Note that the tilt angle of the tilt base with respect to the surface of the nonmagnetic base is tilted by approximately 45 ° in the Z-axis direction from the XY plane. By configuring in this way, the conventional azimuth sensor can measure the magnitude of a three-dimensional magnetic field with a spatial resolution of about several hundred μm by the first to third magnetic sensor elements. Miniaturization in the Z-axis direction is possible.

Japanese Patent No. 2579995 (page 3, FIG. 1)

However, the configuration of the conventional azimuth sensor described above causes a problem that the detection sensitivities in the XYZ axis directions are not equal. That is, the sensitivity of the first and second magnetic sensor elements arranged on the X-axis and the Y-axis is the same, but the detection sensitivity in the height direction (Z-axis direction) by the third magnetic sensor element is different from that, Since the third magnetic sensor element is arranged to be inclined with respect to the other first and second magnetic sensor elements, this detection sensitivity is lowered.

Here, problems in this conventional configuration will be described.
FIG. 10 is a diagram showing a concept of detection axes of a three-axis magnetic sensor in a conventional configuration. The X axis and Y axis shown in the figure indicate the coordinate axes in the direction of detection sensitivity of the first and second magnetic sensor elements, and the Z axis indicates the coordinate axes in the direction orthogonal to the X axis and the Y axis. ing. Z ′ represents the direction of the detection axis of the third magnetic sensor element.

In order to calculate the azimuth angle, the output of three orthogonal magnetic sensor elements excluding the offset is required. As shown in FIG. 10, when these magnetic sensor elements can be arranged on three axes in the orthogonal XYZ directions, calculation can be performed using outputs from the respective axial directions, and the detection sensitivities are almost equal. However, since the direction of detection sensitivity in the third magnetic sensor element in the conventional configuration is inclined 45 degrees in the Z′-axis direction, the magnetic sensor of the third magnetic sensor element when the geomagnetism is directed in the Z-axis direction. since the output Z _'H is not a maximum, the detection sensitivity is lowered. Further, an output vector obtained from the magnetic sensor output Z ′ _H is an output vector obtained from Z _H which is originally required for calculation and a magnetic sensor output Y _H obtained from the second magnetic sensor element arranged on the Y axis, This is a combined vector with the offset vector. That is, in order to obtain the magnetic sensor output Z _H necessary for the original azimuth calculation, the magnetic sensor output Y _H together with the magnetic sensor output Z ′ _H and the offset amount are required. As described above, the magnetic sensor output Z ′ _H and the magnetic sensor output Y _H not only have different detection sensitivities, but also have a problem that the calculation process becomes complicated when performing the azimuth calculation.

  In order to calculate the azimuth accurately and accurately, an offset corresponding to a change in the surrounding magnetic field environment is acquired, and the magnetic sensor output points in the first to third magnetic sensor elements of the XYZ axes are on the sphere. It becomes necessary to become. In this way, when the detection sensitivity of the XYZ axes in the conventional azimuth sensor is different, the magnetic sensor output figure from the first to third magnetic sensor elements becomes an ellipsoid, and thus the offset due to the magnetization of the device is accurately obtained. Therefore, it is impossible to accurately calculate the azimuth angle using this offset.

  Further, in order to eliminate the problem of the sensitivity decrease in the Z-axis direction in the conventional azimuth sensor, the magnetic sensor output of the third magnetic sensor element in the Z-axis direction is amplified to adjust the XYZ-axis sensitivity equivalently. Although a method is also conceivable, if this measure is taken, the resolution of the Z-axis is deteriorated with respect to the resolution of the XY-axis, and as a result, the magnetic sensor output obtained from these first to third magnetic sensor elements is used. Even if the offset calculation is performed, it can be easily understood that the target azimuth angle cannot be calculated with high accuracy.

  Therefore, although the conventional azimuth sensor can be reduced in size and height by inclining one magnetic sensor, the target azimuth angle cannot be calculated with high accuracy.

  Accordingly, in view of the above problems, the present invention is a small and low-profile azimuth sensor that has an equivalent sensitivity without lowering the sensitivity of the magnetic sensor output from the first to third magnetic sensor elements, and its azimuth. An object is to provide an electronic azimuth meter equipped with a sensor.

  In order to solve the above-mentioned problems, the orientation sensor of the present invention and the electronic orientation meter equipped with the orientation sensor basically adopt the following forms.

An azimuth sensor according to the present invention is a first azimuth sensor in which first to third magnetic sensor elements respectively arranged on XYZ axes for detecting orthogonal magnetic fields are arranged on a planar substrate.
Are arranged so that the detection axis of the first magnetic sensor element is parallel to the surface of the flat substrate, and the second magnetic sensor is arranged so that the detection axis of the second magnetic sensor element is on the surface of the flat substrate. The third magnetic sensor is disposed on a first plane having a predetermined angle θ with respect to the third magnetic sensor element, and the detection axis of the third magnetic sensor element is at an angle (90 ° −θ) with respect to the plane substrate surface. And it is arrange | positioned on the 2nd plane from which the angle | corner which a 1st plane makes is 90 degrees, It is characterized by the above-mentioned.

  The azimuth sensor according to the present invention is characterized in that the angle θ is 45 °.

  The azimuth sensor according to the present invention further includes a driving IC for driving the above-described first to third magnetic sensor elements and detecting a magnetic sensor output on a flat substrate. It is.

  The azimuth sensor according to the present invention is characterized in that the above-described first magnetic sensor is laminated on the upper surface of the drive IC.

  The azimuth sensor according to the present invention further includes an inclination sensor that detects an inclination angle with respect to the surface of the flat substrate described above.

  The azimuth sensor according to the present invention further includes a tilt sensor that detects the tilt angle with respect to the surface of the flat substrate described above, and the tilt sensor is disposed on the upper surface of the drive IC. Is.

  An electronic device according to the present invention obtains output values obtained from the first to third magnetic sensor elements in the above-described orientation sensor, and a magnetic field offset due to the influence of magnetization of peripheral components, and a device equipped with the orientation sensor It has an arithmetic processing unit for calculating the azimuth and display means for displaying the azimuth.

  According to the present invention, even if the first to third magnetic sensor elements are arranged on the XYZ axes, the detection sensitivity of the XYZ axes is not lowered and the equivalent sensitivity is achieved while being small and low-profile. I can do it.

  In addition, an electronic apparatus equipped with the azimuth sensor of the present invention is thin, can be a portable information terminal that has good XYZ axis detection sensitivity and can display an accurate azimuth angle.

  The azimuth sensor according to the present invention includes a first magnetic sensor element disposed so as to be parallel to the surface of the planar substrate, and second and third magnetic sensor elements disposed in a plane of about 45 degrees with respect to the planar substrate. And adopting a configuration in which the detection axes of the first to third magnetic sensor elements are arranged to be orthogonal to each other.

  The first magnetic sensor element described above can be obtained by forming the first magnetic sensor element on a silicon wafer by a thin film process and then dicing it into a single piece. The second and third magnetic sensor elements are processed and ground on the back and side surfaces of the silicon wafer so that the single first magnetic sensor element can be disposed on the substrate at an inclination angle of 45 degrees. Obtained by. Details of the manufacturing methods of these first to third magnetic sensor elements will be described later.

(Orientation sensor configuration)
First, the configuration of the direction sensor of the present invention will be described. FIG. 1A is a perspective view showing a configuration of an orientation sensor having a triaxial magnetic sensor element which is a basic configuration of the present invention. In the figure, (b) is a top plan view of the azimuth sensor shown in (a), and (c) shows a side view.

  As shown in FIG. 1 (a), the azimuth sensor 20a of the present invention includes a magnetic sensor 24 arranged so that the detection axis of the first magnetic sensor element 1a is parallel to the surface of the flat substrate 30, and a second sensor. A magnetic sensor 26 arranged on a first plane whose detection axis in the magnetic sensor element 1b is a predetermined angle with respect to the surface of the planar substrate 30, here θ = 45 degrees, and a third magnetic sensor element And a magnetic sensor 28 disposed on a second plane whose detection axis in 1c is (90 ° −θ) with respect to the surface of the flat substrate 30 and whose angle with the first plane is 90 °. Configured. That is, in this configuration, the magnetic sensor 26 and the magnetic sensor 28 are arranged so that the sensor detection direction is 90 degrees.

  Further, as shown in FIG. 1B, the first to third magnetic sensor elements 1a to 1c are driven on the flat substrate 30 and outputted from the first to third magnetic sensor elements 1a to 1c. A sensor drive detection circuit 22 for detecting a magnetic sensor output is arranged around the magnetic sensors 24, 26, and 28. The connection between the electrode terminal of the sensor drive detection circuit 22 and the wiring of the flat substrate 30 is connected by wire bonding (not shown). If the electrode pads provided on the magnetic sensors 26 and 28 are arranged at the edge of the sensor, the connection with the wiring arranged on the flat substrate 30 becomes easy. Similarly, the magnetic sensor 24 is connected to the wiring on the planar substrate 30 by wire bonding or the like. In this way, the wiring on the planar substrate 30 is connected to the electrode terminals of the sensor drive detection circuit 22 so that the first to third magnetic sensor elements 1a to 1c can be driven and the detection signals can be taken out. Become.

  And as shown in FIG.1 (c), in order to protect the electronic components containing these magnetic sensors 24, 26, and 28 and the sensor drive detection circuit 22, it seals with the protective film 14, and the direction of this invention A sensor 20a is configured.

  Here, the detection directions of the first to third magnetic sensor elements 1a to 1c mounted on the azimuth sensor 20a of the present invention will be described using the first magnetic sensor element as an example with reference to FIG. FIG. 2 is a drawing for explaining the detection direction of the magnetic sensor element mounted on the direction sensor of the present invention. The structures of the second and third magnetic sensor elements are different only in the mounting form, and the configuration is the same, so the description here is omitted.

  The first magnetic sensor element 1a is formed on the non-magnetic base 8 and functions as a flux gate type magnetic sensor in which the periphery of the magnetic core 10 is wound around the coil layer 12, and The magnetic core 10 is excited by the wound coil layer 12 and a magnetic field can be detected from the electrode pad 16 by using a pulse output obtained at the time of magnetization reversal. Thus, by constituting the first magnetic sensor element 1a and applying the excitation current from the electrode pad 16, the sensor detection direction 18 becomes parallel to the direction in which the magnetic material is magnetized by the magnetic field generated by the coil.

  The first to third magnetic sensor elements 1a to 1c thus configured are arranged along the XYZ axes (sensor detection directions 18 are arranged along the XYZ axes). In the same manner as described above, it is possible to obtain the azimuth sensor 20a having a small size and a low profile, but without lowering the detection sensitivity of the XYZ axes and further having equivalent sensitivity. In addition, according to this form, the reason why the detection sensitivity of the XYZ axes does not decrease will be described later. Also, because of such a configuration, the direction sensor 20a can be mounted on a small portable information terminal.

(Electronics)
Next, the configuration of the electronic apparatus of the present invention on which the above-described direction sensor 20a is mounted will be described. FIG. 3 is a diagram showing the configuration of the electronic apparatus of the present invention.

  As shown in FIG. 3, the electronic device of the present invention is a portable electronic device such as a mobile phone, and has a three-axis magnetic sensor 1 and a sensor drive detection circuit 22 that constitute the direction sensor 20a described above. In addition to the azimuth sensor 20a, a calculation unit 34 for calculating a magnetic field offset due to the influence of magnetization of peripheral components and a azimuth calculation is further provided. The electronic apparatus also includes an orientation display device 36 that displays the orientation result obtained by the computation performed by the computation device 34.

  In addition, in this figure, although the example (structure example incorporated in CPU of portable devices etc.) which comprised the arithmetic unit 34 as a member different from the direction sensor 20a was shown, this arithmetic unit 34 is integrated with the direction sensor 20a. It may be arranged in a configured package. As described above, when the computing device 34 is incorporated in the package of the azimuth sensor 20a, the size of the azimuth sensor 20a increases accordingly, but the computation load on the host side which is a portable device is reduced. There are advantages.

(Manufacturing method of magnetic sensor and direction sensor)
Next, a method for manufacturing the magnetic sensors 26 and 28 constituting the azimuth sensor 20a of the present invention will be described with reference to FIGS. FIG. 4 is a drawing for explaining a method for manufacturing the magnetic sensor 26. The magnetic sensor 26 and the magnetic sensor 28 are different in the direction of mounting on the flat substrate 30 but have the same element configuration. Therefore, in the following description, although it demonstrates as a manufacturing method of the magnetic sensor 26, it should be noted that this manufacturing method is applicable also to the magnetic sensor 28. FIG.

  First, the magnetic sensor 24 shown in FIG. 1 and the first fixing jig 2a shown in FIG. 4 (a) having a plurality of predetermined notch grooves arranged on the surface are prepared.

  Next, as shown in FIG. 4B, the surface of the first magnetic sensor element 1a is formed in the notch groove of the first fixing jig 2a in each of the notch grooves of the first fixing jig 2a. The magnetic sensor 24 is inserted in the direction in which it is placed inside. Here, the notched groove surface of the first fixing jig 2a and the surface of the first magnetic sensor element 1a come into contact with each other, but the contact surface between the magnetic sensor 24 and the first fixing jig 2a. Since the surface of the first magnetic sensor element 1a is covered with a protective film, the element surface is not damaged.

  Next, a part of the magnetic sensor 24 protruding from the first fixing jig 2a is ground by using means such as lapping, and the structure shown in FIG. After that, the ground magnetic sensor 26a is removed from the first fixing jig 2a.

  Next, as shown in FIG. 4D, the magnetic sensors 26a are rotated by 45 degrees to fix the respective magnetic sensors 26a in the cutout grooves of the second fixing jig 2b. At this time, it is desirable to fix the second fixing jig and the magnetic sensor 26a using a heat-bonding layer that can be easily peeled off.

  Then, the structure shown in FIG. 4D is ground from the back surface (the lower side of the drawing) to a desired position by lapping or the like, and processed into the shape of the magnetic sensor 26b, as shown in FIG. Get a structure.

Finally, the magnetic sensor 26 shown in FIG. 4 (f) can be obtained by taking out the magnetic sensor 26 b from the second fixing jig 2 b in the structure shown in FIG. 4 (e).
The magnetic sensors 26 and 28 manufactured in this way are arranged at predetermined positions on the flat substrate 30 shown in FIG. Furthermore, after the sensor drive detection circuit 22 is arranged, each electronic component is mounted using means such as wire bonding, and then sealed with the protective film 14, thereby completing the orientation sensor 20a of the present invention.

(Azimuth calculation principle)
Next, a method for calculating the azimuth angle θ when the azimuth sensor 20a of the present invention is used will be described. FIG. 5 is a drawing for explaining a calculation method of the direction sensor 20a of the present invention. In addition, the X axis shown in this figure shows the coordinate axis of the detection axis direction of the 1st magnetic sensor element 1a, and the YZ axis shows the coordinate axis orthogonal to this. Further, U and V shown in the figure indicate the detection axis directions of the second and third magnetic sensor elements 1b and 1c arranged at an angle of 45 degrees with the planar substrate 30.

As can be seen from this figure, the azimuth sensor 20a of the present invention has the detection axis directions of the second and third magnetic sensor elements 1b and 1c arranged in the coordinate axis U and V directions, and has the detection sensitivity obtained by these magnetic sensors. Since they are the same, the Z-axis used in the calculation using the magnetic sensor output U _H from the second magnetic sensor element 1b and the magnetic sensor output V _H obtained from the third magnetic sensor element 1c, etc. Direction magnetic sensor output Z _H (magnetic sensor output in the Z-axis direction) can be acquired without degrading, and the target azimuth angle θ can be calculated accurately using these values. .

  Therefore, the azimuth sensor 20a of the present invention employs means for converting the coordinate system of the magnetic sensor output from the second and third magnetic sensor elements 1b and 1c into horizontal coordinates in order to calculate the azimuth angle θ. Yes.

  As described above, since the first magnetic sensor element 1a in the azimuth sensor 20a of the present invention is arranged in parallel to the surface of the flat substrate 30, the calculation can be performed using the magnetic sensor output as it is. The magnetic sensor outputs of the second to third magnetic sensor elements 1b and 1c are Y-axis which is a direction horizontal to the flat substrate 30 and perpendicular to the first magnetic sensor element 1a using the magnetic sensor output in that direction. It is necessary to convert the output into the Z-axis direction which is the direction and the direction perpendicular to the planar substrate 30.

Here, the specific calculation method is shown below.
The magnetic sensor output from the second magnetic sensor element 1b, the output by geomagnetism, and the offset are respectively U _S , U _H , U _offs , the magnetic sensor output from the third magnetic sensor element 1c, the output by geomagnetism, and the offset _Are V _S , V _H , and V _offs , respectively, the magnetic sensor outputs U _S , V _S and y axis from the second and third magnetic sensor elements 1b and 1c, and the outputs yH and zH due to the geomagnetism of the z axis. The relationship can be expressed by the following formulas (1) and (2).

The following formulas (3) and (4) can be derived from the above formulas (1) and (2).

Generally, the output x _H by geomagnetism can be represented by the following formula as the inner product of the direction vectors x and geomagnetic vector S _h facing the detection axis of the magnetic sensor element (5), the based on it (3) The following formulas (6) and (7) can be obtained by developing the formulas (4) and (4).

FIG. 6 is a diagram showing the concept of the relationship between the magnetic sensor output and offset of the first to third magnetic sensor elements 1a to 1c arranged on three orthogonal axes. In the figure, reference numeral 6a indicates an output vector from the magnetic sensor element, reference numeral 6b indicates an output vector by geomagnetism, reference numeral 6c indicates an offset, reference numeral 6d indicates an output coordinate of the magnetic sensor element, and reference numeral 6e indicates The offset coordinates are shown. Note that x _S , y _S , and z _S indicated by output coordinate values of the magnetic sensor element indicate magnetic sensor output values in the respective axial directions, and (x _S1 , y _S1 , z _S1 ) The magnetic sensor output value at the time of measurement is shown. Further, (x _offs , y _offs , z _offs ) indicates an offset value under the certain environment.

As shown in FIG. 6, the first to third magnetic sensor elements 1a to 1c are magnetic sensor elements arranged on three orthogonal axes. When the sensitivity of the magnetic sensor elements on each axis is equal, The sensor output coordinates (x _S1 , y _S1 , z _S1 ) take a point on a sphere centered at (x _offs , y _offs , z _offs ). That is, the radius of the sphere indicates a size corresponding to the output by the geomagnetism, and in an environment where the magnitude of the geomagnetism does not change, the output coordinates of the magnetic sensor element are represented on this sphere regardless of the direction. be able to.

Further, the magnetic sensor output xs (x coordinate in 6d) of the first magnetic sensor element 1a is represented by an output vector 6a. The output vector 6b by the geomagnetism from the first magnetic sensor element 1a and the arrival of the peripheral device. It can be expressed by the sum with the magnetic offset vector 6e. Specifically, it can be expressed by the following formula (8).

The Y-axis direction that is a direction that is horizontal to the plane substrate 30 and orthogonal to the first magnetic sensor element 1a in calculating the target azimuth angle θ by the above relational expressions (6), (7), and (8). Azimuth calculation with respect to conversion to the magnetic sensor output of the second magnetic sensor element 1b arranged on the Z axis and the magnetic sensor output of the third magnetic sensor element 1c arranged in the Z-axis direction that is perpendicular to the plane substrate 30 Therefore, basic relational expressions (9) and (10) for obtaining (x _H , y _H , z _H ) necessary for the calculation can be obtained.

The offsets (x _offs , y _offs , z _offs ) correspond to the center coordinates of the output sphere as described above. In general, the center coordinates of a sphere can be calculated using four points on a spherical surface, and if this is used, magnetism from four or more sets of first to third magnetic sensor elements 1a to 1c is obtained. The center coordinates of the sphere can be obtained from the sensor output data, and an offset generated by magnetization can be obtained by this method. Then, using this offset, for example, the target azimuth angle θ can be acquired by the following equation (11).

  As described above, in the azimuth sensor 20a of the present invention, the sensitivities of the first to third magnetic sensor elements 1a to 1c arranged on the XYZ axes are equivalent, and the magnetic sensor output from the first magnetic sensor element 1a is equivalent. In addition, since the magnetic sensor outputs after the correction obtained by adding and dividing the magnetic sensor outputs of the second and third magnetic sensor elements 1b and 1c inclined at the same angle from the flat substrate 30 are used, Compared to the configuration, the offset calculation and the azimuth calculation are not complicated.

  In addition, the azimuth sensor 20a of the present invention is similar to the conventional configuration in that the first to third magnetic sensor elements 1a to 1c, while the height direction (Z-axis direction) is reduced and the height is reduced. In particular, the resolution of the third magnetic sensor element 1c can be kept high, whereby the target azimuth angle θ can be obtained with high accuracy.

Next, another configuration example of the direction sensor of the present invention will be described. FIG. 7A is a perspective view showing a configuration of an azimuth sensor 20b equipped with a three-axis magnetic sensor that is a basic configuration of the present invention.
In the figure, (b) is a top plan view of the azimuth sensor 20b, and (c) shows a side view.

  As shown in FIGS. 7A to 7C, the azimuth sensor 20b of the present invention differs from the first embodiment only in that magnetic sensors 24, 26, and 28 are arranged on the sensor drive detection circuit 22. The arrangement directions of the detection axes in the first to third magnetic sensor elements 1a to 1c are the same direction. In the previous embodiment, a configuration example in which wire bonding is used for connection between the electrode terminal of the sensor drive detection circuit 22 and the wiring on the planar substrate 30 has been described. In order to reduce the area, the sensor driving circuit 22 and the planar substrate 30 are mounted by flip chip mounting. In this flip chip mounting, the electrode terminals of the sensor drive detection circuit 22 are bump plated and mounted so that the electrode terminals of the sensor drive detection circuit 22 can be directly connected to the wiring on the flat substrate 30. Yes.

  Specifically, bump plating with Au or the like is formed on the electrode terminal surface of the sensor drive detection circuit 22 so as to be higher than the wiring height formed on the element surface. Then, a low melting point electric connection material such as solder is attached in advance to the wiring on the flat substrate 30, the bump plating and the wiring are aligned and temporarily fixed, and both are passed through a reflow furnace or the like. Connect the members.

  As described above, by arranging the magnetic sensors 24, 26, and 28 on the upper surface of the sensor drive detection circuit 22, in addition to the effect of the first embodiment, the area in the plane direction is reduced. Thus, the effect of further miniaturization can be obtained.

  Next, still another configuration example of the direction sensor of the present invention will be described. FIG. 8A is a perspective view showing the configuration of the azimuth sensor 20c of the present invention. In the figure, (b) is a top plan view of the direction sensor 20c, and (c) shows a side view.

  As shown in FIGS. 8A to 8C, the azimuth sensor 20c of the present invention has a configuration in which a tilt sensor 32 is further incorporated in addition to the configuration of the azimuth sensor shown in the first embodiment, and is an electronic device. Even when the user uses the electronic device while tilting, the magnetic sensor outputs from the first to third magnetic sensor elements 1a to 1c are corrected based on the tilt sensor output output from the tilt sensor 32. Thus, the correct azimuth angle θ can be calculated. Note that the tilt sensor 32 shown in FIG. 8 is an acceleration sensor of a type in which a central weight supported by a beam is tilted according to the tilt and a stress applied to the beam is detected by piezoresistance.

  Thus, the configuration of the azimuth sensor 20c in which the three magnetic sensors 24, 26, 28 and the tilt sensor 32 are arranged, in addition to the effects of the previous embodiment, the electronic device including the azimuth sensor 20c is tilted with respect to the horizontal plane. An orientation sensor and an electronic device that can correct the magnetic sensor output using the tilt sensor output from the tilt sensor 32 and obtain the correct azimuth angle θ even if the tilt sensor 32 is disposed. Can do.

(Azimuth calculation principle)
Next, calculation of the azimuth angle θ according to the embodiment of the present invention will be described.
In general, the azimuth angle θ is calculated from xH calculated from the magnetic sensor outputs from the first to third magnetic sensor elements 1a to 1c arranged on the XYZ three-dimensional coordinates and offsets obtained from the respective magnetic sensor outputs. , YH, zH, and the angle βg formed between the X axis and the horizontal plane, and the rotation angles α and β calculated from the angle αg formed between the Y axis and the horizontal plane, are given by the following relational expressions.

The rotation angles α and β included in the above expression indicate the rotation angle around the X axis and the rotation angle around the Y axis, respectively. Is equal to the rotation angle beta is the pitch angle beta _g, the rotational angle alpha for different roll angle alpha _g, and determines a rotation angle alpha, beta by using the conversion formula (13) (14).

  By using the above equations (12) to (14), an accurate azimuth angle θ can be obtained even in an environment where the device is inclined. In addition, although the calculation by XYZ three-dimensional coordinate was demonstrated here, as shown in FIG. 5, the 1st-3rd magnetic sensor elements 1a-1c mounted in the direction sensor of this invention are 2nd, 2nd, The three magnetic sensor elements 1b and 1c are arranged at a predetermined angle. Therefore, as described in the previous embodiment, the magnetic sensor output from the second and third magnetic sensor elements 1b and 1c is in a direction that is horizontal to the plane substrate 30 and perpendicular to the first magnetic sensor element 1a. It is necessary to convert the magnetic sensor output in the axial direction and in the Z-axis direction that is perpendicular to the planar substrate 30, and the conversion is performed by applying the equations (8) to (10) described in the previous embodiment. XH, yH, and zH corresponding to the later magnetic sensor output can be obtained.

  In addition, in the calculation method for correcting the output of the magnetic sensor related to the tilt of the device, as described above, only one simple addition / division conversion process is added, and almost the same effect as the conventional method can be obtained. .

(Electronics)
Next, a configuration example of the electronic device in this embodiment will be described. FIG. 9 is a conceptual diagram showing the configuration of the electronic device of the present invention.

  The direction sensor 20c shown in the present embodiment is different from the magnetic sensor 1 and the sensor drive circuit 22 shown in the first embodiment only in that an inclination sensor 32 is arranged. Only the arithmetic means described above in the device 34 is different. Other configurations and functions are the same. With this configuration, even when the user of the electronic device uses the electronic device while tilting, the magnetic sensor output is corrected using the tilt angle output from the tilt sensor 32, and the target azimuth angle θ is accurately determined. It becomes possible to calculate.

In the above embodiment, the example in which the two second and third magnetic sensor elements 1b and 1c are arranged at an angle of 45 degrees with respect to the planar substrate 30 has been described. The arrangement of the second and third magnetic sensor elements 1b and 1c is not particularly limited to 45 degrees. What is important is that the two inclined second and third magnetic sensor elements 1b and 1c are arranged on the horizontal flat substrate 30 so that the detection axes thereof are orthogonal to each other and have the same detection sensitivity. The second and third magnetic sensor elements 1b and 1c thus formed and the first magnetic sensor element 1a constitute three orthogonal axes. Further, the second and third magnetic sensor elements 1b and 1c are not formed by tilting only one of the third magnetic sensor elements at a predetermined angle as in the conventional configuration. 2. The point at which the third magnetic sensor elements 1b, 1c are tilted is the point of the present invention that constitutes the three orthogonal axes. In order to reduce the package height of the azimuth sensors 20a-20c, the tilt angle is set to 45. When it is set to the degree, it is possible to make the height the lowest.

  In the above embodiment, the method of forming the magnetic sensors 26 and 28 having a predetermined angle by processing the non-magnetic base after cutting it into a single piece has been described, but this configuration is also particularly limited. It is not something. What is important is to arrange the detection axes of the two second and third magnetic sensor elements 1b and 1c so as to be orthogonal to each other and to have the same detection sensitivity. You may utilize the method of etching the base which arrange | positions the 2nd, 3rd magnetic sensor element 1b, 1c, and making an inclined surface, and the thin film process of forming the convex part which has an inclined surface in the base surface. However, if this thin film process is used, the process of forming on the slope becomes difficult. Therefore, as shown in the previous embodiment, it is more accurate to adopt the means for processing the non-magnetic base, It is suitable for forming the third magnetic sensor elements 1b and 1c.

  As described above, the configuration of the azimuth sensors 20a to 20c of the present invention in which three of the first to third magnetic sensor elements 1a to 1c are arranged reduces the detection sensitivity of the XYZ axes while being small and low-profile. It can be set as the structure which is excellent in resolution. Furthermore, the 1st-3rd magnetic sensor elements 1a-1c which have equivalent sensitivity, and the direction sensor which can be mounted in a portable information terminal which arranged these three magnetic sensor elements orthogonally can be obtained.

It is the perspective view, upper part top view, and side view which show the structure of the direction sensor of this invention. It is drawing for demonstrating the detection direction of the magnetic sensor element mounted in the direction sensor of this invention. It is a conceptual diagram which shows the structure of the electronic device of this invention. It is drawing which shows the manufacturing method of the magnetic sensor mounted in the direction sensor of this invention. It is drawing which shows the relationship of the detection coordinate axis of the magnetic sensor mounted in the direction sensor of this invention. It is drawing for demonstrating the relationship between the magnetic sensor output of 3 orthogonal axes | shafts of a magnetic sensor mounted in the azimuth | direction sensor of this invention, and an offset. It is the perspective view, upper part top view, and side view which show the structure of the direction sensor which is the 2nd Example of this invention. It is the perspective view, upper part top view, and side view which show the structure of the direction sensor which is the 3rd Example of this invention. It is a conceptual diagram which shows the structure of the electronic device which is the 3rd Example of this invention. It is the figure which showed the relationship of the detection coordinate axis of the magnetic sensor in the structure of the conventional direction sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic sensor 1a 1st magnetic sensor element 1b 2nd magnetic sensor element 1c 3rd magnetic sensor element 2a 1st fixing jig 2b 2nd fixing jig 4 Inclined stand 6a, 6b Output vector 6c Offset vector 8 Nonmagnetic base 10 Magnetic core material 12 Coil layer 13 Magnetic core 14 Protective film 16 Electrode pad 18 Sensor detection direction 20a-20c Direction sensor 22 Sensor drive detection circuit 24, 26, 26a, 26b, 28 Magnetic sensor 30 Flat substrate 32 Inclination Sensor 34 Computing device 36 Direction display device

Claims (7)

In the azimuth sensor that arranges the first to third magnetic sensor elements arranged on the XYZ axes on the flat substrate for detecting orthogonal magnetic fields,
The first magnetic sensor element is arranged so that the detection axis of the first magnetic sensor element is parallel to the surface of the flat substrate,
The second magnetic sensor element is disposed on a first plane in which a detection axis of the second magnetic sensor element is a predetermined angle θ with respect to the planar substrate surface,
In the third magnetic sensor element, the detection axis of the third magnetic sensor element is an angle (90 ° −θ) with respect to the surface of the flat substrate, and an angle formed with the first plane is 90 °. Disposed on the second plane,
An orientation sensor characterized by that. The direction sensor according to claim 1, wherein the predetermined angle θ is 45 °. The direction sensor according to claim 1 or 2, further comprising a driving IC for driving the first to third magnetic sensor elements on the planar substrate. The azimuth sensor according to claim 3, wherein the first magnetic sensor element is stacked on the upper surface of the drive IC. The azimuth sensor according to claim 1, further comprising an inclination sensor that detects an inclination angle with respect to the surface of the planar substrate. An inclination sensor for detecting an inclination angle with respect to the planar substrate surface;
The azimuth sensor according to claim 3 or 4, wherein the tilt sensor is disposed on the upper surface of the drive IC. An output value obtained from the first to third magnetic sensor elements in the orientation sensor according to any one of claims 1 to 6, obtaining a magnetic field offset due to the influence of magnetization of peripheral components, and the orientation sensor An arithmetic processing unit for calculating the orientation of a device equipped with
An electronic device comprising: display means for displaying an orientation of the device.

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