JP4855454B2 - Position detection device and electronic apparatus using the position detection device - Google Patents

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.

  The inventors of the present application have conventionally proposed a position detection device described in Patent Document 2 and the like, and at present, this position detection mechanism is widely used as a key part of a camera shake correction device for a digital still camera.

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

  FIG. 12 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 or the Hall sensor 11 so that the difference value of the Hall output voltage 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 the region where the moving range exceeds several mm, there is a problem that the entire mechanism becomes large, and it has not been put into practical use.

  In position detection in a narrow range, in order to reduce the number of parts, position detection in one axial direction is performed using a magnet and one Hall sensor in an arrangement as shown in FIG. It is also possible to perform. Further, in position detection that requires high accuracy in a narrow range, there are cases where position detection is performed with a special arrangement using two magnets as in Patent Document 3.

  On the other hand, a method using an encoder is generally used when performing a wide range of position detection exceeding 5 mm as required by a lens position detection device for zooming or autofocusing of a digital still camera or a digital video camera. 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. is there.

Japanese Patent Laid-Open No. 2002-287991 International Publication No. WO2002 / 086694 Pamphlet 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.

  If the position detection device of Patent Document 2 proposed by the inventors of the present application is used, a high accuracy of about 0.1% is achieved for a 2 to 3 mm stroke required for position detection for camera shake correction, and it is widely used. However, a wide range of position detection of 5 mm or more, which is required for a lens position detection device for camera zoom or autofocus, has not been realized with the same high accuracy.

  In addition, 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 difference value of the Hall output voltage is relative to the movement distance in the lateral direction of the permanent magnet. If designed to change linearly, 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. This configuration is not practical because portable devices such as digital still cameras have a strong demand for downsizing.

  In addition, in the methods described in Patent Document 3 and Patent Document 4, it is difficult in principle to arrange the magnet so that the output of the Hall sensor is linear in a wide range, and it is difficult to perform zooming and autofocusing of the camera. For this reason, there is a problem that it is impossible to detect a wide range of 5 mm or more as required by a lens position detecting device.

  In addition, the method described in Patent Document 5 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. Therefore, there is a problem that it is necessary to prepare a special magnet that defines the size of the non-magnetized portion.

  For these reasons, up to the present, position detection devices using magnets with a high accuracy of about 0.1% of the position detection range have only been put into practical use within a moving distance of a few millimeters or less. It was.

  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 parts, and the position of the central part of the three movement ranges is detected using the relational expression (Va−Vb) when the output of the magnetic sensor is Va and Vb, respectively. , Both ends of the movement range divided into three For a position detecting device characterized by detecting the position by using a relational expression of (Va + Vb).

  According to a second aspect of the present invention, there is provided a magnetic flux detection means comprising a set of two magnetic sensors disposed on a substrate and having a magnetic sensitivity direction perpendicular to the substrate, and the magnetic sensitivity of the magnetic sensor. A magnet which is supported in a direction parallel to a straight line connecting the centers of the parts and movable in a plane parallel to the substrate, and is magnetized with N and S poles perpendicular to the substrate. Magnetic flux generating means and signal processing means for detecting a position based on an output from the magnetic sensor, the signal processing means dividing the moving range of the magnet into three, and the center of the three divided moving ranges. For the portion, when the output of the magnetic sensor is Va and Vb, respectively, position detection is performed using the relational expression of (Va−Vb) / (Va + Vb), and both end portions of the movement range divided into three are obtained. Is the relationship of (Va + Vb) A position detecting device, characterized in that the detection position using.

  Further, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the three divisions are the central two places out of the movement range of the magnet and the one at one end. It is characterized by being divided into three so that there is one place and one place at the other end.

  According to a fourth aspect of the present invention, in the first, second, or third aspect of the present invention, the midpoint of a straight line connecting between the centers of the magnetic sensing portions of the magnetic sensor and the midpoint of the moving range of the magnet. And are the same.

  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.

  In other words, the rectangular parallelepiped magnet 31 is supported so as to be movable in a direction parallel to the straight line connecting the centers of the magnetic sensing portions of the Hall sensors 32 a and 32 b and in a plane parallel to the substrate 33. N pole and S pole are magnetized in the vertical 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 in the cuboid magnet 31 to the center of the magnetic sensing part 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.

  Also, 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.

  FIG. 2 is a block diagram of an example 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. Show.

  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, position detection is performed by using the difference between the output voltages of the two hall sensors based on the positional relationship between the moving magnet and the two hall sensors, and the sum of the output voltages of the two hall sensors is used. The feature is that the position detection is properly used.

  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 uses the relational expression (Va−Vb) when the outputs of the hall sensors 32a and 32b are Va and Vb, respectively, in the central portion of the three-divided movement range. Position detection is performed, and position detection is performed using the relational expression (Va + Vb) for both end portions of the movement range divided into three.

  In addition, for the central part of the movement range divided into three, position detection is performed using the relational expression (Va−Vb) / (Va + Vb) when the outputs of the hall sensors 32a and 32b are Va and Vb, respectively. Position detection is performed using the relational expression (Va + Vb) for both end portions of the movement range divided into three.

  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 120, where the length of the long side of the moving magnet is 100. 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 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 such a driving / processing circuit, a difference signal (Va−Vb), a sum signal (Va + Vb), a difference using the hall output voltage Va of the first hall sensor 32a and the hall output voltage Vb of the second hall sensor 32b. The output value Vo, which is the value of / sum signal (Va−Vb) / (Va + Vb), corresponds to the position of the rectangular parallelepiped magnet 31.

  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 the values of (Va−Vb), (Va + Vb), (Va−Vb) / (Va + Vb) are calculated by the calculation processing unit. Etc., and the values of (Va−Vb), (Va + Vb), (Va−Vb) / (Va + Vb) can be obtained with the analog signal as it is.

<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 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), (Va + Vb), (Va−Vb) / (Va + Vb), and the position of the rectangular parallelepiped magnet 31 is detected.

  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. When (Va-Vb) or (Va-Vb) / (Va + Vb) is used to detect the position, the position is detected using (Va + Vb) except for the two parts in the middle of the movement range divided into approximately four parts. Good characteristics are often obtained.

<Each Example of Position Detection Device>
Example 1
Next, a specific example 1 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 will be described. A design example of optimum values of parameters of each component in FIG. 1 will be described.

  As shown in FIGS. 10A and 10B to be described later, the length A1 of the cuboid magnet 31 in the long side direction X = 6.3 mm, the length A2 of the cuboid magnet 31 in the short side direction Y = 4.7 mm, The length in the thickness direction Z of the rectangular parallelepiped magnet 31 (the length in the magnetizing direction of the magnet) is set to A3 = 2.3 mm.

  Further, the distance B1 = 2.2 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 = 3.1 mm from the center of the magnetic sensing part of the second hall sensor 32b is set.

  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 and 3B and FIGS. 4A to 4C are diagrams showing 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 a1 of the output voltage Va of the first Hall sensor 32a with respect to the moving distance of the magnet, and a change b1 of the output voltage Vb of the second Hall sensor 32b with respect to the moving distance of the magnet. . FIG. 3B shows a change c1 in the difference (Va−Vb) in 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 d1 in the sum (Va + Vb) in the output voltage. 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 e1 of the value (Va-Vb) computed using the value of the Hall output voltage Vb of 32b, and the ideal straight line f1.

  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 g1 and the ideal straight line h1 of the value (Va + Vb) 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.

  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 i1 of the value (Va + Vb) 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 j1.

  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 1300 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) calculated using the value of the Hall output voltage Vb has high linearity and matches well with 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. It can be seen that a value (Va + Vb) calculated by using the Hall output voltage Va of the second Hall sensor 32b and the Hall output voltage Vb of the second Hall sensor 32b has a high linearity and is in good agreement with the ideal straight line.

  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. It can be seen that a value (Va + Vb) calculated by using the Hall output voltage Va of the second Hall sensor 32b and the Hall output voltage Vb of the second Hall sensor 32b has a high linearity and is in good agreement with the ideal straight line.

  Here, the ideal straight line f1 shown 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) 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. It is a straight line.

  The ideal straight line h1 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) and the moving distance of the rectangular magnet 31 are a straight line connecting the values (Va + Vb) calculated using the values of the output voltages Va and Vb of the two Hall sensors 32a and 32b at −1.75 mm. .

  The ideal straight line j1 shown in FIG. 4C is 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. ) And the distance (Va + Vb) calculated by using the values of the output voltages Va and Vb of the two hall sensors 32a and 32b at +3.5 mm.

  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) has a large deviation from the ideal straight line f1, or a value (Va + Vb) calculated using the output voltage Va of the first hall sensor 32a and the output voltage Vb of the second hall sensor 32b Is large from the ideal straight line h1, or the value (Va + Vb) calculated using the output voltage Va of the first hall sensor 32a and the output voltage Vb of the second hall sensor 32b from the ideal straight line j1. If the deviation is large, the position detection error becomes large.

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

  FIG. 5A is a diagram showing an error p1 in position detection converted from a deviation between the simulation result e1 and the ideal straight line f1 shown in FIG. FIG. 5B is a diagram showing an error q1 in position detection converted from the deviation between the simulation result g1 shown in FIG. 4B and the ideal straight line h1. FIG. 5C is a diagram showing an error r1 in position detection converted from a deviation between the simulation result i1 and the ideal straight line j1 shown in FIG. FIG. 5D is a diagram illustrating the full-range position error of FIGS. 5A to 5C.

  From the results shown in FIGS. 5A to 5C, the position detection error is about 5.0 μm at the maximum, and the resolution is 0.07% 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. 4A may be the ideal straight line f1. Furthermore, the straight line obtained by the least square method from the simulation result shown in FIG. 4B may be the ideal straight line h1. Furthermore, the straight line obtained by the least square method from the simulation result shown in FIG. 4C may be the ideal straight line j1. 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. 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.

Example 2
Next, a specific example 2 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 will be described. A design example of optimum values of parameters of each component in FIG. 1 will be described.

  As shown in FIGS. 11A and 11B to be described later, the length A1 of the cuboid magnet 31 in the long side direction X = 7.0 mm, the length A2 of the cuboid magnet 31 in the short side direction Y = 5.8 mm, The length in the thickness direction Z of the rectangular parallelepiped magnet 31 (the length in the magnetizing direction of the magnet) A3 = 1.8 mm.

  Further, the distance B1 = 3.36 mm from the plane 100 facing the Hall sensors 32a and 32b of the rectangular parallelepiped 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 5.1 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. 6A and 6B and FIGS. 7A to 7C are diagrams showing 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. 6A is a diagram showing a change a2 in the output voltage Va of the first Hall sensor 32a with respect to the moving distance of the magnet, and a change b2 in the output voltage Vb of the second Hall sensor 32b with respect to the moving distance of the magnet. . FIG. 6B shows a change c2 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 d2 in the sum (Va + Vb) in the output voltage. FIG.

  FIG. 7 (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 at the two middle portions (−1.75 mm to +1.75 mm). It is a figure which shows the change e2 of the value (Va-Vb) / (Va + Vb) computed using the value of the Hall output voltage Vb of 32b, and the ideal straight line f2.

  FIG. 7B 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 center of the movement distance divided into four equal parts. It is a figure which shows the change g2 and the ideal straight line h2 of the value (Va + Vb) computed using the value of Hall output voltage Va of this and the Hall output voltage Vb of the 2nd Hall sensor 32b.

  FIG. 7C 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 equal parts. It is a figure which shows the change i2 and the ideal straight line j2 of the value (Va + Vb) computed using the value of the output voltage Va and the Hall output voltage Vb of the 2nd Hall sensor 32b.

  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 1300 mT (general neodymium sintered magnet). Value).

  From the magnetic simulation result shown in FIG. 7A, the moving distance of the rectangular parallelepiped magnet 31 is divided into four equal parts, and the hall output voltage Va of the first hall sensor 32a and the second hall sensor 32b 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. 7B, the moving distance of the rectangular parallelepiped magnet 31 is divided into four equal parts, and the first hall sensor 32a is located in a portion close to the first hall sensor 32a other than the two middle portions. It can be seen that a value (Va + Vb) calculated by using the Hall output voltage Va of the second Hall sensor 32b and the Hall output voltage Vb of the second Hall sensor 32b has a high linearity and is in good agreement with the ideal straight line.

  From the magnetic simulation result shown in FIG. 7C, 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 second hall sensor 32b other than the two middle portions. It can be seen that a value (Va + Vb) calculated by using the Hall output voltage Va of the second Hall sensor 32b and the Hall output voltage Vb of the second Hall sensor 32b has a high linearity and is in good agreement with the ideal straight line.

  Here, the ideal straight line f2 shown in FIG. 7A 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 h2 shown in FIG. 7B 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) and the moving distance of the rectangular magnet 31 are a straight line connecting the values (Va + Vb) calculated using the values of the output voltages Va and Vb of the two Hall sensors 32a and 32b at −1.75 mm. .

  The ideal straight line j2 shown in FIG. 7C is 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. ) And the distance (Va + Vb) calculated by using the values of the output voltages Va and Vb of the two hall sensors 32a and 32b at +3.5 mm.

  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) is largely deviated from the ideal straight line f2, it 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 deviation of the value (Va + Vb) from the ideal straight line h2 is large, or the value (Va + Vb) 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 deviation from the ideal straight line j2 is large, the position detection error becomes large.

  8 (a) to 8 (c) show the magnet movement distance converted from the ideal straight line and the deviation of the magnetic simulation results shown in FIGS. 6 (a) and 6 (b) and FIGS. 7 (a) to 7 (c). It is a figure which shows a position detection error.

  FIG. 8A is a diagram showing an error p2 in position detection converted from the deviation between the simulation result e2 and the ideal straight line f2 shown in FIG. 7A. FIG. 8B is a diagram showing an error q2 in position detection converted from a deviation between the simulation result g2 shown in FIG. 7B and the ideal straight line h2. FIG. 8C is a diagram showing an error r2 in position detection converted from the deviation between the simulation result i2 and the ideal straight line j2 shown in FIG. FIG. 8D is a diagram illustrating the full-range position error of FIGS. 8A to 8C.

  From the results shown in FIGS. 8A to 8C, the position detection error is about 2.1 μm at the maximum, and the resolution is 0.03% 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. 7A may be the ideal straight line f2. Further, a straight line obtained by the least square method from the simulation result shown in FIG. 7B may be used as the ideal straight line h2. Furthermore, the straight line obtained by the least square method from the simulation result shown in FIG. 7C may be the ideal straight line j2. 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. 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.

<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.

  9 (a) and 9 (b) are schematic configuration diagrams of a position detection device using a conventional magnet and a hall sensor as a comparative example, FIG. 9 (a) is a cross-sectional view, and FIG. 9 (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.

  10 (a) to 10 (d) and FIGS. 11 (a) to 11 (d) are an equivalent view for comparison of the configuration of the position detection device of the present invention shown in FIG. 1 and the configuration of the conventional position detection device. (A) is a cross-sectional view of the configuration according to the present invention, (b) is a top view of the configuration according to the present invention, (c) is a cross-sectional view of the conventional configuration, and (d) is a top view of the conventional configuration. (FIG. 10 shows the configuration of the first embodiment, and FIG. 11 shows the configuration of the second embodiment). Here, the Hall sensors 32a and 32b in FIGS. 10A and 10B and FIGS. 11A and 11B are sensors integrally enclosed 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. 10 (c) and 10 (d) and FIGS. The length C1 in the side direction X = 15.4 mm, the length C2 in the short side direction Y of the cuboid magnet 41 = 15.3 mm, the length C3 in the thickness direction Z of the cuboid magnet 41 = 4.3 mm, and the hole in the cuboid magnet 41 The distance D1 = 6.3 mm from the surface facing the sensor to the magnetic sensing part of the Hall sensor, and the distance D2 = 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. .

  Thus, the configuration of the position detection device 30 shown in FIGS. 10A and 10B and FIGS. 11A and 11B according to the present invention is the same as that shown in FIGS. 10C and 10D for comparison. It can be seen that the size and thickness of the entire position detection device can be significantly reduced as compared with the conventional configuration of the position detection device 40 shown in 11 (c) and 11 (d).

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 example of a position detection circuit of the position detection apparatus shown in FIG. (A), (b) is the figure (the 1) which shows the result of having calculated | required the magnetic flux density of the Hall sensor part with respect to the moving distance of the rectangular parallelepiped magnet in Example 1, or the value after the calculation from the magnetic simulation. (A) thru | or (c) is a figure (the 2) which shows the result of having calculated | required the magnetic flux density of the Hall sensor part with respect to the moving distance of the rectangular parallelepiped magnet in Example 1, or the value after a calculation from the magnetic simulation. (A) to (d) are the movements of the magnet converted from the ideal straight line in Example 1 and the deviation of the magnetic simulation results shown in FIGS. 3 (a), 3 (b) and 4 (a) to 4 (c). It is a figure which shows the position detection error with respect to distance. (A), (b) is the figure (the 1) which shows the result of having calculated | required the magnetic flux density of the Hall sensor part with respect to the moving distance of the rectangular parallelepiped magnet in Example 2, or the value after the calculation from the magnetic simulation. (A) thru | or (c) are the figures (the 2) which show the result of having calculated | required the magnetic flux density of the Hall sensor part with respect to the moving distance of the rectangular parallelepiped magnet in Example 2, or the value after the calculation from the magnetic simulation. (A) to (d) are the movements of the magnet converted from the ideal straight line in Example 2 and the deviation of the magnetic simulation results shown in FIGS. 6 (a), 6 (b) and 7 (a) to 7 (c). It is a figure which shows the position detection error with respect to distance. 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. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of Example 1 of the position detection apparatus of this invention, and the structure of the conventional position detection apparatus as an equal magnification for a comparison, (a) is sectional drawing of the structure by this invention, (b) is this FIG. 2 is a top view of a configuration according to the invention, FIG. 3C is a cross-sectional view of a conventional configuration, and FIG. FIG. 2 is a diagram showing the configuration of the position detection device according to the second embodiment of the present invention and the configuration of a conventional position detection device as an equal-magnification view for comparison, in which FIG. FIG. 2 is a top view of a configuration according to the invention, FIG. 3C is a cross-sectional view of a conventional configuration, and FIG. 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 parts, and the central part of the three divided moving ranges is positioned using the relational expression (Va−Vb) when the output of the magnetic sensor is Va and Vb, respectively. A position detection apparatus that detects and performs position detection using a relational expression of (Va + Vb) for both end portions of the movement range divided into three. 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 movement range of the magnet is divided into three, and the relational expression of (Va−Vb) / (Va + Vb) is obtained when the output of the magnetic sensor is set to Va and Vb, respectively, in the central portion of the movement range divided into three. A position detection apparatus, wherein position detection is performed using a relational expression of (Va + Vb) for both end portions of the three-divided movement range.   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. Or the position detection apparatus of 2.   4. The position detecting device according to claim 1, wherein a midpoint of a straight line connecting the centers of the magnetic sensing parts of the magnetic sensor is the same as a midpoint of the moving range of the magnet.   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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