JP5074342B2 - Position detection device and electronic apparatus using the position detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve miniaturization by simple configurations, and to highly precisely detect a wide range distance even when configuring components are configured of general-purpose articles or easily available components. <P>SOLUTION: Two hall sensors 32a and 32b whose magnetic sensing directions are perpendicular to a substrate on which those two hall sensors 32a and 32b are arranged are set as a pair, and a magnet whose N pole and S pole are magnetized perpendicular to the substrate is arranged so as to be movably supported in parallel with a straight line connecting the centers of the hall sensors 32a and 32b and the substrate. This position detection device is provided with a signal processing circuit for, when the outputs of the two hall sensors 32a and 32b are respectively defined as Va and Vb, dividing the moving range of the magnet into three, and for carrying out position detection by properly using (Va-Vb) or (Va-Vb)/(Va+Vb), (Va-Vb)/(nVa+mVb), and (Va-Vb)/(mVa+nVb) (the absolute values of n and m are real numbers which are not the same value). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a position detection device and an electronic device using the position detection device, and more particularly to a position detection device using a magnet and a hall sensor and an electronic device using the position detection device.

  In recent years, various sensors have been used everywhere. For example, a camera shake correction device used in a digital still camera, a digital video camera, or a lens position detection device for zooming or autofocus requires a sensor having a function for instantaneously detecting a position with high accuracy. In recent years, there is a strong demand for downsizing of the entire device, and thus downsizing of the sensor itself is required. Furthermore, there are various demands such as a sensor having a long life and a characteristic that is not easily affected by dust and oil (grease).

  In order to meet such a demand, a position detection method using a magnetic sensor as a sensor is known. As the magnetic sensor, for example, the method described in Patent Document 1 can be changed and modified. That is, as shown in FIG. 3 of Patent Document 1, a magnet is included in a movable part, and the movement is detected using a plurality of magnetic sensors.

  Here, the principle and configuration of position detection using a plurality of magnetic sensors will be described.

  FIG. 8 is a diagram for explaining a position detection method using a plurality of Hall sensors as magnetic sensors. Two holes according to the change in magnetic flux density due to the movement of the permanent magnets 23 arranged opposite to the two hall sensors 11, 12 arranged at a predetermined interval in the side direction (arrow direction). The Hall output voltages of the sensors 11 and 12 change, respectively. The position value of the permanent magnet 23 can be detected by processing the difference value of the Hall output voltages by the differential signal processing circuit. At the time of this position detection, the moving direction of the permanent magnet 23 is in a state parallel to the straight line connecting the two Hall sensors 11 and 12.

  Further, in order to save the labor of calibration, the size of the permanent magnet 23 and the Hall sensor 11 so that the difference value of the Hall output voltage described above changes linearly with respect to the movement distance in the side surface direction of the permanent magnet 23. , 12 and the distance between the hall sensors 11, 12 and the permanent magnet 23 are generally designed.

  This configuration has good characteristics as long as the relative movement range of the magnet and the Hall sensor is within a few mm, and is used as a key part in a camera shake correction device of a single-lens reflex digital camera. However, in a region where the moving range exceeds several mm, there is a problem that the whole mechanism becomes large, and it has not been put into practical use.

  In addition, when position detection is performed with high accuracy in a wide temperature range, for example, the output signal processing method disclosed in Patent Document 2 is used to suppress the change in characteristics due to changes in the ambient temperature of the Hall sensor or magnet, thereby detecting the position. May be performed.

  Further, in position detection in a narrow range, in order to reduce the number of parts, for example, in an arrangement as shown in FIG. 6 of Patent Document 4, a magnet and one hall sensor are used in one axial direction. It is also possible to perform position detection.

  In position detection that requires high accuracy in a narrow range, for example, as in Patent Document 3, position detection may be performed with a special arrangement using two magnets.

  On the other hand, when performing position detection over a wide range, a method using an encoder is common. However, when an encoder is used, there is a problem that a complicated processing circuit including a counter for processing a signal from the sensor is required. In addition, if the moving device and the encoder step out, desired characteristics cannot be obtained, so that the moving device and the encoder are not suitable for a high-speed moving object.

  In addition, in position detection that requires high accuracy over a wide range, the position detection may be performed by switching the calculation method according to the output from the magnetic sensor in the arrangement as shown in FIG. .

Japanese Patent Laid-Open No. 2002-287991 JP 2004-348173 A JP 2004-245765 A JP 2002-229090 A JP 2006-292396 A

  In recent years, there has been an increasing demand to realize position detection in a wide range using a magnetic sensor that is non-contact and has a long life and is not affected by dust or dust. Furthermore, there is a strong demand for downsizing of portable devices such as digital cameras.

  When position detection is performed over a wide range using the method described in a comparative example (method described in Patent Document 1) described later, the above-described difference value of the Hall output voltage is linear with respect to the movement distance in the lateral direction of the permanent magnet. If the design is made to change to, the size of the magnet, the distance between the two Hall sensors, and the distance between the Hall sensor and the magnet are increased, which makes it difficult to reduce the size of the position detection device.

  In addition, the methods described in Patent Document 3 and Patent Document 4 described above are difficult in principle to dispose the magnet so that the output of the Hall sensor is linear in a wide range. There has been a problem that position detection over a wide range of 5 mm or more, which is required for a lens position detection device for focusing, is impossible.

  Moreover, the method described in Patent Document 5 described above has a problem that the size of the magnet in the moving distance direction is longer than the position detection range, and is not suitable for downsizing. Furthermore, the magnet has two N poles and two S poles and is magnetized perpendicular to the magnetic sensing surface of the magnetic sensor, but the linearity changes depending on the size of the non-magnetized part. For this reason, there is a problem that it is necessary to prepare a special magnet that defines the size of the non-attached portion.

  For these reasons, up to the present, only a small position detection device using a magnet with a high accuracy of about 0.1% of the position detection range has been put into practical use within a moving distance of a few millimeters. It wasn't.

  The present invention has been made in view of such problems. The object of the present invention is simple even when the hall sensor is used as a magnetic sensor and the component parts are constituted by general-purpose products or easily available parts. An object of the present invention is to provide a position detection device capable of realizing downsizing with a simple configuration and capable of detecting a wide range of distances with high accuracy, and an electronic apparatus using the position detection device.

  The present invention has been made to achieve such an object, and the invention according to claim 1 is arranged on a substrate, and two magnetic sensors having a magnetic sensitive direction perpendicular to the substrate. Is supported in a direction parallel to a straight line connecting the centers of the magnetic sensing portions of the magnetic sensor and in a plane parallel to the substrate, with respect to the substrate. Magnetic flux generation means comprising a magnet with N and S poles magnetized in the vertical direction, and signal processing means for detecting the position based on the output from the magnetic sensor, the signal processing means comprising: The movement range is divided into three, and the central part of the three movement ranges is divided into (Va−Vb) or (Va−Vb) / (Va + Vb) when the output of the magnetic sensor is Va and Vb, respectively. Detect the position using the relational expression Among the three divided movement ranges, the position of the magnetic sensor that outputs Va is detected using the relational expression (Va−Vb) / (nVa + mVb), and among the three divided movement ranges, Vb is The output magnetic sensor side is characterized in that position detection is performed using a relational expression of (Va−Vb) / (mVa + nVb) (however, the absolute values of n and m are not real values).

  The invention according to claim 2 is the invention according to claim 1, wherein the three divisions are divided into two central portions, one at one end, and the other of the movement range of the magnet. It is characterized in that it is divided into three so as to be one place at one end.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the midpoint of a straight line connecting the centers of the magnetic sensing portions of the magnetic sensor and the midpoint of the moving range of the magnet are It is characterized by being the same.

  The invention described in claim 4 is characterized in that, in the invention described in claim 1, 2 or 3, one of n and m in the relational expression is zero.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the magnetic sensor is integrally enclosed in one package.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the magnetic sensor does not have a magnetic chip for performing magnetic amplification.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the magnetic sensor is a Hall sensor including a III-V group compound semiconductor such as GaAs, InAs, InSb. It is characterized by.

  The invention according to claim 8 is the invention according to any one of claims 1 to 6, wherein the magnetic sensor is a Hall sensor including a group IV semiconductor such as Si or Ge.

  According to a ninth aspect of the present invention, there is provided an electronic apparatus using the position detecting device according to any one of the first to eighth aspects.

  According to the present invention, even when the hall sensor is used as a magnetic sensor and the component parts are constituted by general-purpose products or easily available parts, it is possible to achieve downsizing with a simple configuration and to increase a wide range of distances. It is possible to provide a position detection device capable of detecting with high accuracy and an electronic apparatus using the position detection device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Configuration of Position Detection Device of the Present Invention>
1A and 1B are schematic configuration diagrams of a position detection device according to the present invention, in which FIG. 1A is a sectional view and FIG. 1B is a top view. In the figure, reference numeral 30 is a position detecting device, 31 is a rectangular parallelepiped magnet (magnetic flux generating means) magnetized with one N pole and one S pole, and 32a and 32b are hall sensors (magnetic sensor / magnetic flux detection) in which two are combined. Means) 33 indicates a substrate on which the hall sensor 32a (first hall sensor) and the hall sensor 32b (second hall sensor) are mounted. The position detection apparatus according to the present invention can be configured using variously shaped magnets and various Hall sensors.

  The hall sensors 32 a and 32 b are arranged on the substrate 33 and a set of two sensors whose magnetism sensitive direction is perpendicular to the substrate 33. The rectangular parallelepiped magnet 31 is configured to be magnetized perpendicularly to the substrate 33 on which the Hall sensors 32a and 32b are mounted, and is arranged so as to be movable along the x direction within one plane 100 facing the substrate 33. Has been.

  That is, the rectangular parallelepiped magnet 31 is supported so as to be movable in a plane parallel to the straight line connecting the centers of the magnetic sensing portions of the Hall sensors 32 a and 32 b and parallel to the substrate 33, and perpendicular to the substrate 33. N and S poles are magnetized in the direction.

  Here, the meaning of being able to move in a direction parallel to the straight line connecting the centers of the magnetic sensing portions of the two hall sensors 32a and 32b and in a plane parallel to the substrate 33 is the magnetic sensitivity of the hall sensors 32a and 32b. This means that, when a straight line connecting the centers of the portions and a straight line indicating the moving direction of the rectangular magnet 31 are projected on any same plane parallel to the substrate 33, the respective extension lines are parallel. Further, the midpoint of the straight line connecting the centers of the magnetic sensing portions of the two Hall sensors 32a and 32b is the same as the midpoint of the moving range of the rectangular parallelepiped magnet 31.

  As the rectangular parallelepiped magnet 31, ferrite, neodymium boron, samarium cobalt magnet, or the like can be applied. In the case of a thin magnet, a plastic magnet or a rubber magnet can also be used. The magnet is magnetized in a direction in which N and S poles are magnetized in a direction perpendicular to the substrate 33.

  A straight line connecting the center of the magnetic sensing part of the first hall sensor 32a and the center of the magnetic sensing part of the second hall sensor 32b configured as a set of hall sensors is also in the x direction. The hall sensors 32 a and 32 b are disposed at positions facing the surface of the rectangular parallelepiped magnet 31.

  In the figure, A1 indicates the length in the long side direction X of the cuboid magnet 31, A2 indicates the length in the short side direction Y of the cuboid magnet 31, and A3 indicates the length in the thickness (magnetization) direction Z of the cuboid magnet 31. ing. B1 indicates the distance from the plane 100 facing the substrate 33 of the hall sensors 32a and 32b of the rectangular parallelepiped magnet 31 to the centers of the magnetic sensing portions of the hall sensors 32a and 32b. B2 indicates the distance connecting the center of the magnetic sensing part of the first hall sensor 32a and the center of the magnetic sensing part of the second hall sensor 32b.

  The hall sensors 32a and 32b include III-V group compound semiconductors such as GaAs, InAs, and InSb. Further, it may contain a group IV semiconductor such as Si or Ge.

  FIG. 2 is a block diagram of the position detection circuit of the position detection apparatus shown in FIG. 1. In FIG. 2, reference numeral 19 denotes a drive circuit, 20 denotes a signal processing unit, 21a and 21b denote differential amplifiers, and 22 denotes a calculation processing unit. ing.

  The drive circuit 19 includes a pair of hall sensors 32a and 32b and a power supply unit Vc that supplies voltage to the hall sensors 32a and 32b. The first hall sensor 32a is composed of a positive input terminal 32a (A), a positive output terminal 32a (B), a negative input terminal 32a (C), and a negative output terminal 32a (D). The sensor 32b includes a positive input terminal 32b (E), a positive output terminal 32b (F), a negative input terminal 32b (G), and a negative output terminal 32b (H). The positive output terminal 32a (B) The output voltage Va of the first hall sensor 32a is output from the negative output terminal 32a (D), and the output of the second hall sensor 32b is output from the positive output terminal 32b (F) and the negative output terminal 32b (H). The voltage Vb is output.

  The signal processing unit 20 performs position detection based on outputs from the hall sensors 32a and 32b. In general, even if the configuration of the position detection device 30 such as the positional relationship between the cuboid magnet 31 and the Hall sensors 32a and 32b is optimized, the range in which the magnetic flux density changes linearly with the movement of the cuboid magnet 31 generally moves. It is about 70 to 80% of the length of the long side of the rectangular parallelepiped magnet 31. In the present invention, the moving range of the rectangular parallelepiped magnet 31 is divided into three.

  The movement range of the magnet 31 is divided into three so that the movement range of the rectangular parallelepiped magnet 31 is divided into approximately four equal parts, two at the center, one at one end, and one at the other end. is there.

  By dividing the object in the center of the moving range of the cuboid magnet 31, the accuracy in the vicinity of the end point of the moving range becomes the same at both end points. In other words, if the object is not at the center of the moving range of the cuboid magnet 31, the accuracy in the vicinity of both end points changes. That is, the accuracy near one of the end points is deteriorated. Furthermore, by dividing the moving range of the rectangular magnet 31 into approximately four parts and dividing it into two central portions and other end points, the accuracy in the vicinity of both end points and the accuracy in the central portion often approach each other. .

  The signal processing unit 20 according to the present invention has (Va−Vb) or (Va−Vb) when the outputs of the hall sensors 32a and 32b are Va and Vb, respectively, in the central portion of the three movement ranges. The position is detected using the relational expression of / (Va + Vb), and the relational expression of (Va−Vb) / (nVa + mVb) is obtained for the first hall sensor 32a side that outputs Va out of the three movement ranges. The position detection is performed using the relational expression (Va−Vb) / (mVa + nVb) for the second hall sensor 32b side that outputs Vb in the movement range divided into three. is there.

  However, the absolute values of n and m are real numbers that are not equivalent. One of n or m is zero. That is, there are optimum values for n and m depending on the configuration such as the magnet size and the distance between the magnet and the Hall sensor, but the accuracy is often improved by setting one to zero.

  Further, two Hall sensors 32a and 32b are integrally sealed in one package. If the characteristics (sensitivity and offset) of the two Hall sensors are too far apart, the position detection accuracy will deteriorate. In order to make the characteristics of the two Hall sensors uniform, for example, by placing two Hall sensors in the place where the wafer was located in the manufacturing stage in one package, the above-mentioned problems can be solved, and a high-precision position can be obtained. A detection device can be configured.

  The hall sensors 32a and 32b do not have a magnetic chip for performing magnetic amplification. The Hall sensors 32a and 32b have a magnetic chip inside, and a configuration for amplifying the detection magnetic field of the sensor portion is known. However, in the configuration of the present invention, magnetic saturation of the magnetic chip becomes a problem, and the wide sensor It is difficult to accurately detect the position within a range. By using a Hall sensor that is not magnetically amplified, the position of a wide range can be accurately detected.

  By adopting such a configuration, the range in which the magnetic flux density changes linearly with the movement of the magnet extends to about 20 when the length of the long side of the moving magnet is 10. That is, even if the size of the magnet is reduced, position detection can be performed with high accuracy within a range exceeding 5 mm. When the Hall sensor is a Hall IC having an amplifier, the number of output signal lines can be reduced as compared with the Hall sensor, so that the mounting board can be saved in space and the influence of external noise can be reduced.

  In addition, an electronic device using such a position detection device can be provided. The position detection device of the present invention is suitable for an electronic apparatus having a camera unit, represented by a digital camera, a camcorder, a camera-equipped mobile phone, and the like. It can be suitably used when detecting the position of a lens or CCD with high accuracy.

The operation of the position detection circuit shown in FIG. 2 will be described below.
The position detection device 30 includes a drive circuit 19 for two hall sensors 32a and 32b, and a signal processing circuit 20 that performs position detection based on outputs from the hall sensors 32a and 32b.

  The first hall sensor 32a includes a positive input terminal 32a (A), a positive output terminal 32a (B), a negative input terminal 32a (C), and a negative output terminal 32a (D). The second hall sensor 32b includes a positive input terminal 32b (E), a positive output terminal 32b (F), a negative input terminal 32b (G), and a negative output terminal 32b (H).

  The positive input terminal 32a (A) of the first hall sensor 32a and the positive input terminal 32b (E) of the second hall sensor 32b are connected, and the negative input terminal 32a (C) of the first hall sensor 32a is connected. The negative input terminal 32b (G) of the second hall sensor 32b is connected to serve as the input terminal of the drive circuit 19.

  The positive output terminal 32a (B) and the negative output terminal 32a (D) of the first hall sensor 32a are connected to the first differential amplifier 21a of the signal processing circuit 20, and the positive output terminal of the second hall sensor 32b. 32 b (F) and the negative output terminal 32 b (H) are connected to the second differential amplifier 21 b of the signal processing circuit 20. The output terminal of the first differential amplifier 21a and the output terminal of the second differential amplifier 21b are input to the AD converter and transmitted to the calculation processing unit 22 that calculates the output as appropriate.

  By using the drive circuit 19 and the signal processing circuit, the hall output voltage Va of the first hall sensor 32a and the hall output voltage Vb of the second hall sensor 32b are used (Va−Vb), (Va−Vb) / The rectangular magnet 31 has an output value Vo that is a value of (Va + Vb), (Va−Vb) / (nVa + mVb), (Va−Vb) / (mVa + nVb) (where the absolute values of n and m are not the same value). It corresponds to the position of.

  In the configuration of the present invention, the input terminals of the first hall sensor 32a and the second hall sensor 32b are connected in parallel, but this is not particularly limited to parallel connection. Needless to say, more accurate instrumentation amplifiers may be used for the differential amplifiers 21a and 21b. Further, the signals 21a and 21b are AD-converted, and values of (Va−Vb), (Va−Vb) / (Va + Vb), (Va−Vb) / (nVa + mVb), (Va−Vb) / (mVa + nVb) (However, the absolute values of n and m are real numbers that are not the same value) were calculated by the calculation processing unit 22, but a separate differential amplifier was provided and the analog signal remained as (Va−Vb), (Va It is also possible to obtain values of (−Vb) / (Va + Vb), (Va−Vb) / (nVa + mVb), (Va−Vb) / (mVa + nVb) (however, the absolute values of n and m are not the same value).

<Position detection method of the present invention>
Next, a position detection method will be described.
In the conventional position detection method, the position of the rectangular parallelepiped magnet 31 is detected using only the difference output or difference / sum output of the two hall sensors 32a and 32b.

  Unlike the conventional method, the position detection method of the present invention is calculated from the hall output voltage Va of the first hall sensor 32a and the hall output voltage Vb of the second hall sensor 32b according to the position of the rectangular magnet 31. , (Va−Vb) or (Va−Vb) / (Va + Vb), (Va−Vb) / (nVa + mVb), (Va−Vb) / (mVa + nVb), where the absolute values of n and m are The position of the cuboid magnet 31 is detected by using a real number that is not the same value.

  Specifically, the moving range of the rectangular magnet 31 is divided into about four equal parts, and the two middle portions are calculated from the hall output voltage Va of the first hall sensor 32a and the hall output voltage Vb of the second hall sensor 32b. Position detection is performed using (Va−Vb) or (Va−Vb) / (Va + Vb), and the portion close to the first Hall sensor 32a is the second portion other than the middle two portions of the movement range divided into about four equal parts. The position is detected using (Va−Vb) / (nVa + mVb) calculated from the hall output voltage Va of the first hall sensor 32a and the hall output voltage Vb of the second hall sensor 32b, and the middle of the movement range divided into about 4 Of these two portions, the portion close to the second hall sensor 32b is the hall output voltage Va of the first hall sensor 32a and the hall output voltage Vb of the second hall sensor 32b. Ri computed (Va-Vb) / Doing detection position using (mVa + nVb), it is often good characteristics can be obtained.

<Example of position detection device>
Next, a specific embodiment of the position detection device 30 will be described.
A case where a position detection range of 7 mm (± 3.5 mm) is detected with a position detection accuracy within 0.1% of the position detection range in a wide temperature range will be described. A design example of optimum values of parameters of each component in FIG. 1 will be described.

  As shown in FIGS. 7A and 7B described later, the length A1 of the cuboid magnet 31 in the long side direction X = 3.5 mm, the length A2 of the cuboid magnet 31 in the short side direction Y = 2.3 mm, The length in the thickness direction Z of the rectangular parallelepiped magnet 31 (the length in the magnetizing direction of the magnet) is A3 = 2.7 mm.

  Further, the distance B1 = 3.2 mm from the plane 100 facing the Hall sensors 32a and 32b of the cuboid magnet 31 to the center of the magnetically sensitive portion of the Hall sensors 32a and 32b, and the center of the magnetically sensitive portion of the first Hall sensor 32a The distance B2 from the center of the magnetic sensing part of the second hall sensor 32b is set to 0.8 mm.

  In the above design, mounting the hall sensors 32a and 32b in one package reduces the arrangement error of the hall sensors 32a and 32b, and can contribute to the higher accuracy of the position detection device. For example, it is also possible to provide Hall sensors 32a and 32b on a Si substrate.

  Therefore, it is desirable to enclose the first hall sensor 32a and the second hall sensor 32b in one package.

  FIGS. 3A to 3C and FIGS. 4A to 4C are diagrams illustrating the results of obtaining the output voltage of the Hall sensor with respect to the moving distance of the rectangular parallelepiped magnet or the calculated value from the magnetic simulation.

  FIG. 3A is a diagram showing a change a of the output voltage Va of the first Hall sensor 32a with respect to the moving distance of the magnet. FIG. 3B is a diagram showing a change b in the output voltage Vb of the second Hall sensor 32b with respect to the moving distance of the magnet. FIG. 3C shows a change d in the difference (Va−Vb) in the output voltage between the first Hall sensor 32a and the second Hall sensor 32b with respect to the moving distance of the magnet and a change c in the sum (Va + Vb) of the output voltages. FIG.

  FIG. 4 (a) divides the moving distance of the magnet into four equal parts, and the hall output voltage Va of the first hall sensor 32a and the second hall sensor in the middle two portions (−1.75 mm to +1.75 mm). It is a figure which shows the change e of the value (Va-Vb) / (Va + Vb) computed using the value of the Hall output voltage Vb of 32b, and the ideal straight line f. FIG. 4B shows the first hall sensor 32a in a portion (−3.5 mm to −1.75 mm) close to the first hall sensor 32a among the two portions at the middle of the travel distance divided into four equal parts. It is a figure which shows the change g of the value (Va-Vb) / (nVa + mVb) computed using the value of Hall output voltage Va of this, and the value of Hall output voltage Vb of the 2nd Hall sensor 32b, and the ideal straight line h. FIG. 4C shows a hole of the first hall sensor 32a in a portion (1.75 mm to 3.5 mm) close to the second hall sensor 32b, other than the two portions in the middle of the movement distance divided into four. It is a figure which shows the change i of the value (Va-Vb) / (mVa + nVb) computed using the value of the output voltage Va and the Hall output voltage Vb of the 2nd Hall sensor 32b, and the ideal straight line j. Here, the values of the coefficients n and m being calculated are calculated with n = 0 and m = 1, respectively.

  As preconditions for the magnetic simulation, the sensitivity of the two Hall sensors 32a and 32b is 2.2 mV / mT (sensitivity of a general Hall sensor), and the residual magnetic flux density Br of the rectangular parallelepiped magnet 31 is 1400 mT (general neodymium sintered magnet). Value).

  From the magnetic simulation result shown in FIG. 4 (a), the moving distance of the rectangular magnet 31 is equally divided into four, and the hall output voltage Va of the first hall sensor 32a and the second hall sensor 32b at the two middle portions. It can be seen that the value (Va−Vb) / (Va + Vb) calculated using the value of the Hall output voltage Vb has a high linearity and well matches the ideal straight line.

  From the magnetic simulation result shown in FIG. 4B, the moving distance of the rectangular parallelepiped magnet 31 is equally divided into four parts, and the first hall sensor 32a is located in a portion close to the first hall sensor 32a other than the middle two portions. The value (Va−Vb) / (nVa + mVb) calculated using the Hall output voltage Va of the second Hall sensor 32b and the value of the Hall output voltage Vb of the second Hall sensor 32b has high linearity and may be in good agreement with the ideal straight line. I understand.

  From the magnetic simulation result shown in FIG. 4 (c), the moving distance of the rectangular parallelepiped magnet 31 is equally divided into four, and the first hall sensor 32a is located in a portion close to the second hall sensor 32b other than the two middle portions. The value (Va−Vb) / (mVa + nVb) calculated using the Hall output voltage Va of the second Hall sensor 32b and the value of the Hall output voltage Vb of the second Hall sensor 32b has a high linearity and agrees well with the ideal straight line. I understand.

  Here, the ideal straight line f described in FIG. 4A is a value calculated using the values of the output voltages Va and Vb of the two Hall sensors 32a and 32b when the moving distance of the rectangular magnet 31 is −1.75 mm. (Va−Vb) / (Va + Vb) and a value (Va−Vb) calculated using the values of the output voltages Va and Vb of the two hall sensors 32a and 32b when the moving distance of the rectangular magnet 31 is +1.75 mm. / (Va + Vb).

  The ideal straight line h shown in FIG. 4B is a value calculated using the values of the output voltages Va and Vb of the two Hall sensors 32a and 32b when the moving distance of the rectangular magnet 31 is −3.5 mm ( (Va−Vb) / (nVa + mVb) and a value (Va−Vb) calculated by using the values of the output voltages Va and Vb of the two Hall sensors 32a and 32b when the moving distance of the rectangular magnet 31 is −1.75 mm. ) / (NVa + mVb) (where n = 0 and m = 1).

  The ideal straight line j described in FIG. 4C is a value (Va) calculated using the values of the output voltages Va and Vb of the two hall sensors 32a and 32b when the moving distance of the rectangular magnet 31 is +1.75 mm. −Vb) / (mVa + nVb) and a value calculated by using the values of the output voltages Va and Vb of the two Hall sensors 32a and 32b when the moving distance of the rectangular magnet 31 is +3.5 mm (Va−Vb) / A straight line connecting (mVa + nVb) (where n = 0 and m = 1).

  In general, in order to detect the position using the value on the ideal straight line, the value calculated using the output voltage Va of the first hall sensor 32a and the output voltage Vb of the second hall sensor 32b. When (Va−Vb) / (Va + Vb) has a large deviation from the ideal straight line f, or the output voltage Va of the first hall sensor 32a and the output voltage Vb of the second hall sensor 32b are used for calculation. When the value (Va−Vb) / (nVa + mVb) deviates from the ideal straight line h, or is calculated using the output voltage Va of the first hall sensor 32a and the output voltage Vb of the second hall sensor 32b. When the value (Va−Vb) / (mVa + nVb) thus deviated from the ideal straight line j is large, the position detection error becomes large.

  5 (a) to 5 (c) show the movement distance of the magnet converted from the ideal straight line and the deviation of the magnetic simulation results shown in FIGS. 3 (a) to 3 (c) and FIGS. 4 (a) to 4 (c). It is a figure which shows a position detection error.

  FIG. 5A is a diagram showing an error p in position detection converted from a deviation between the simulation result e and the ideal straight line f shown in FIG. FIG. 5B is a diagram showing an error q in position detection converted from a deviation between the simulation result g and the ideal straight line h shown in FIG. FIG. 5C is a diagram showing an error r in position detection converted from the deviation between the simulation result i and the ideal straight line j shown in FIG.

  From the results shown in FIGS. 5A to 5C, the position detection error is about 3.5 μm at the maximum, and the resolution is 0.05% with respect to the total stroke of 7 mm, achieving highly accurate position detection. I understand that.

  Naturally, the straight line obtained by the least square method from the simulation result shown in FIG. Furthermore, the straight line obtained by the least square method from the simulation result shown in FIG. Furthermore, a straight line obtained by the least square method from the simulation result shown in FIG. If the straight line obtained by the least square method is an ideal straight line, the position detection error is further reduced and the resolution is increased.

  Although the calculation is performed with the values of the coefficients n and m being calculated as n = 0 and m = 1 as described above, the position detection device 30 uses the long side direction of the rectangular parallelepiped magnet 31 even if the numerical values are different. The length A of X, the length A2 of the rectangular parallelepiped magnet 31 in the short side direction Y, the length of the rectangular parallelepiped magnet 31 in the thickness direction Z (the length in the magnetizing direction of the magnet) A3, the Hall sensors 32a and 32b of the rectangular parallelepiped magnet 31 The distance B1 from the plane 100 opposite to the center of the magnetic sensing part of the Hall sensors 32a and 32b, and the distance B2 between the center of the magnetic sensing part of the Hall sensor 32a and the center of the magnetic sensing part of the Hall sensor 32b. Thus, a better result than the comparative example shown below can be obtained.

  For example, in the position detection range of 7 mm, the values of coefficients n and m being calculated in the configuration of A1 = 3.6 mm, A2 = 4.8 mm, A3 = 4.0 mm, B1 = 2.9 mm, B2 = 0.9 mm When n = 0 and m = 1, the position detection error is about 8.9 μm and the resolution is 0.127% with respect to the total stroke of 7 mm, but n = −0.1 and m = 2. As a result, the position detection error is about 6.1 μm, and the resolution is improved to 0.087% with respect to the total stroke of 7 mm. Position detection with position detection accuracy within 0.1% of the position detection range is possible. It becomes.

  Further, as described above, the moving distance of the rectangular parallelepiped magnet 31 is divided into four equal parts and the calculation method is changed. However, it may not be completely divided into four equal parts. Table 1 shows the position detection error when 1.75 mm, which is the absolute value (division position) of the end points of the two middle parts of the four equal parts, is changed from 1.65 mm to 1.85 mm in 0.5 mm steps. Shown in

  From Table 1, it can be seen that a resolution within 0.1% of the stroke can be achieved even when the moving distance of the rectangular magnet 31 is not completely divided into four equal parts.

  As described above, by using the position detection device 30 of the present invention, a small position detection device can be realized as compared with the position detection device described in the following comparative example.

<Comparative example>
As a comparative example, a case will be described in which a position detection range of 7 mm (± 3.5 mm) is detected in a wide temperature range using a conventional method, as in the above-described embodiment.

  6 (a) and 6 (b) are schematic configuration diagrams of a position detecting device using a conventional magnet and a hall sensor as a comparative example, FIG. 6 (a) is a cross-sectional view, and FIG. 6 (b) is a top view. is there. In the figure, reference numeral 41 denotes a rectangular parallelepiped magnet that is unipolarly magnetized perpendicularly to the plane 200 facing the hall sensor, 42a and 42b are hall sensors, and 43 is a substrate on which the hall sensors 42a and 42b are mounted.

  In the figure, C1 is the length in the long side direction X of the cuboid magnet 41, C2 is the length in the short side direction Y of the cuboid magnet 41, and C3 is the length in the thickness direction Z of the cuboid magnet 41 (magnetization of the magnet). Direction length). D1 is the distance from the plane 200 facing the hall sensors 42a and 42b of the rectangular magnet 41 to the center of the magnetic sensing part of the hall sensors 42a and 42b, and D2 is the center of the magnetic sensing part of the hall sensor 42a and the hall sensor 42b. The distance from the center of the magnetosensitive part is shown.

  In this comparative example, the rectangular parallelepiped magnet 41 moves only in the x-axis direction shown in the figure. In addition, the hall sensors 42 a and 42 b are arranged in a plane shape that is horizontal with respect to the moving direction of the rectangular parallelepiped magnet 41.

  FIGS. 7A to 7D are diagrams showing the configuration of the position detection device of the present invention shown in FIG. 1 and the configuration of the conventional position detection device as a comparison isometric view, and FIG. FIG. 3B is a cross-sectional view of a configuration according to the present invention, FIG. 4B is a top view of the configuration according to the present invention, FIG. Here, Hall sensors 32a and 32b in FIGS. 7A and 7B indicate sensors that are integrally sealed in one package.

  In order to perform position detection with position detection accuracy within 0.1% of the position detection range, as shown in FIGS. 7C and 7D, the length C1 = 15. 4 mm, length C2 of the rectangular parallelepiped magnet 41 in the short side direction Y = 15.3 mm, length C3 of the rectangular parallelepiped magnet 41 in the thickness direction Z = 1.3 mm, and the sense of the Hall sensor from the surface facing the Hall sensor of the rectangular parallelepiped magnet 41 The distance D1 to the magnetic part is 6.3 mm, and the distance D2 is 11.6 mm between the center of the magnetic sensing part of the hall sensor 42a and the center of the magnetic sensing part of the hall sensor 42b.

  Accordingly, the configuration of the position detection device 30 shown in FIGS. 7A and 7B according to the present invention is the same as the configuration of the conventional example of the position detection device 40 shown in FIGS. 7C and 7D for comparison. In comparison, it can be seen that the size and thickness of the entire position detection device can be significantly reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the position detection apparatus based on this invention, (a) is sectional drawing, (b) is a top view. It is a block diagram of the position detection circuit of the position detection apparatus shown in FIG. (A) thru | or (c) is a figure (the 1) which shows the result of having calculated | required the output voltage of the Hall sensor with respect to the moving distance of a rectangular parallelepiped magnet, or the value after a calculation from the magnetic simulation. (A) thru | or (c) is a figure (the 2) which shows the result of having calculated | required the output voltage of the Hall sensor with respect to the moving distance of a rectangular parallelepiped magnet, or the value after a calculation from the magnetic simulation. (A) thru | or (c) are the position detection with respect to the moving distance of the magnet converted from the ideal straight line and the shift | offset | difference of the magnetic simulation result shown to Fig.3 (a) thru | or (c) and Fig.4 (a) thru | or (c). It is a figure which shows an error. As a comparative example, it is a schematic block diagram of the position detection apparatus using the conventional magnet and Hall sensor, (a) is sectional drawing, (b) is a top view. FIG. 2 is a diagram showing the configuration of the position detection device of FIG. 1 and the configuration of a conventional position detection device as an equal-magnification view for comparison, in which FIG. FIG. 4C is a top view, FIG. 3C is a cross-sectional view of the conventional configuration, and FIG. 3D is a top view of the conventional configuration. It is a figure for demonstrating the conventional position detection method using the conventional Hall sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st Hall sensor 12 2nd Hall sensor 19 Drive circuit 20 Signal processing circuit 21a, 21b Differential amplifier 22 Arithmetic processing calculation part 23 Permanent magnet 30 Position detection apparatus 31, 41 Cuboid magnet 32a, 42a 1st Hall sensor 32b, 42b Second Hall sensors 32a (A), 32b (E) Positive input terminals 32a (B), 32b (F) Positive output terminals 32a (C), 32b (G) Negative input terminals 32a (D), 32b (H) Negative electrode output terminals 33, 43 Substrate 100 Plane 200 Plane

Claims (9)

Magnetic flux detecting means arranged on a substrate and having two magnetic sensors each having a magnetic sensing direction perpendicular to the substrate as a set;
The magnetic sensor is supported so as to be movable in a plane parallel to a straight line connecting the centers of the magnetic sensing portions of the magnetic sensor and parallel to the substrate, and an N pole and an S pole are attached in a direction perpendicular to the substrate. Magnetic flux generation means comprising magnetized magnets;
Signal processing means for performing position detection based on the output from the magnetic sensor,
The signal processing means
The moving range of the magnet is divided into three, and the central part of the divided moving range is divided into (Va−Vb) or (Va−Vb) / Va / Vb when the outputs of the magnetic sensor are Va and Vb, respectively. Position detection is performed using the relational expression (Va + Vb), and position detection is performed using the relational expression (Va−Vb) / (nVa + mVb) for the magnetic sensor side that outputs Va out of the three movement ranges. The position of the magnetic sensor that outputs Vb is detected using the relational expression (Va−Vb) / (mVa + nVb) in the movement range divided into three (however, the absolute values of n and m) Is a real number that is not the same value).   2. The three-part division is performed by dividing the magnet into three parts so that there are two central parts, one part at one end, and one part at the other end of the movement range of the magnet. The position detection apparatus described in 1.   3. The position detection device according to claim 1, wherein a midpoint of a straight line connecting the centers of the magnetic sensing portions of the magnetic sensor is the same as a midpoint of the moving range of the magnet.   4. The position detection device according to claim 1, wherein one of n and m in the relational expression is zero.   The position detection device according to claim 1, wherein the magnetic sensor is integrally sealed in one package.   6. The position detection device according to claim 1, wherein the magnetic sensor does not include a magnetic chip for performing magnetic amplification.   7. The position detection device according to claim 1, wherein the magnetic sensor is a Hall sensor including a III-V group compound semiconductor such as GaAs, InAs, InSb.   The position detection device according to claim 1, wherein the magnetic sensor is a Hall sensor including a group IV semiconductor such as Si or Ge.   An electronic apparatus using the position detection device according to claim 1.

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