JP2011187024A - Position detection system and multidirectional input device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detection system capable of reducing an influence caused by disturbance from a magnetic field generation component Y, and a multidirectional input device capable of raising a degree of freedom of design of a loaded product and miniaturizing the loaded product. <P>SOLUTION: The position detection system 1 includes: first to third magnetic detection elements 12A-12C which are loaded on a substrate 11; a magnet 13 which is arranged on the substrate 11 and movable with respect to the substrate 11; and a control means for calculating an output in a first direction by an output difference between the first magnetic detection element 12A and the second magnetic detection element 12B and calculating an output in a second direction by an output difference between the second magnetic detection element 12B and the third magnetic detection element 12C where the first magnetic detection element 12A and the third magnetic detection element 12C are arranged at symmetric positions centering around the magnet 13, and the second magnetic detection element 12B is arranged at a middle point position in a virtual circular arc connecting the first magnetic detection element 12A, the second magnetic detection element 12B and the third magnetic detection element 12C. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a position detection system using a magnetic detection element and a multidirectional input device including the position detection system.

  2. Description of the Related Art Conventionally, some multi-directional input devices using a position detection system have the configuration disclosed in Patent Document 1. In this multidirectional input device, as shown in FIG. 6, magnetic detection elements 102 a to 102 d (output voltages V <b> 1 to V <b> 4) are mounted on a substrate 101. Here, four magnetic detection elements 102 a to 102 d are arranged on the substrate 101 at positions symmetrical with respect to the center of the substrate 101. Above the substrate 101, an operating body is provided that can slide in a 360 ° direction with respect to the substrate 101. The operating body includes a magnet 103, an annular coil spring 104 that returns the magnet 103 to the original position when the magnet 103 is moved by a slide operation, and a rotation prevention mechanism 105 that prevents the magnet 103 from rotating. Can be slid as a unit.

  In the position detection system of the multidirectional input device, as shown in FIG. 6, four magnetic detection elements 102a to 102d are symmetrically arranged vertically around the magnet 103, and the four magnetic detection elements 102a to 102d are arranged symmetrically. It arrange | positions at equal intervals in the virtual arc to connect. Such a multi-directional input device is used as an operation input device for a mobile phone. Mobile phones are equipped with components that generate magnetic fields that cause disturbance in magnetic detection, and the distance between these magnetic field generating components and the multidirectional input device is reduced by downsizing the mobile phone.

JP 2005-310670 A

  In the multidirectional input device shown in FIG. 6, for example, if the magnetic field generating component Y is disposed between the magnetic detection elements 102a and 102d, the magnetic detection elements 102a and 102d are affected by disturbance from the magnetic field generating component Y. That is, if position detection is performed in such a state, as shown in FIG. 7, output (output voltage difference (V1-V2), output voltage difference (V3-V4)) is disturbed, and position detection is performed accurately. I can't do it. For this reason, it is necessary to mount the magnetic field generating component away from the multidirectional input device, which reduces the degree of freedom in designing the product on which the multidirectional input device is mounted, and the product cannot be downsized. There is.

  The present invention has been made in view of the above points, and improves the degree of freedom in designing the position detection system and the mounted product that can reduce the influence of disturbance from the magnetic field generating component Y. An object of the present invention is to provide a multidirectional input device that can be miniaturized.

  The position detection system of the present invention includes first to third magnetic detection elements mounted on a substrate, a magnet disposed on the substrate and movable with respect to the substrate, and the first magnetic detection element. And a control means for obtaining an output in the first direction by an output difference of the second magnetic detection element, and obtaining an output in the second direction by an output difference of the second magnetic detection element and the third magnetic detection element; The first magnetic detection element and the third magnetic detection element are arranged at symmetrical positions with respect to the magnet, and the second magnetic detection element includes the first magnetic detection element, It is arranged at a midpoint position in a virtual arc connecting the second magnetic detection element and the third magnetic detection element.

  According to this configuration, since the magnetic field insensitive region can be formed, the influence of disturbance of the magnetic field generating component can be reduced even if the magnetic field generating component is arranged in the magnetic field insensitive region.

  In the position detection system of the present invention, the sliding magnet is a four-pole circular magnet, and is configured so that the polarity changes every 90 °, and corresponds to three of the four magnetic pole regions. It is preferable that the first magnetic detection element, the second magnetic detection element, and the third magnetic detection element are arranged in the region.

  In the position detection system of the present invention, the first direction is a direction along an imaginary line connecting the first magnetic detection element and the third magnetic detection element, and the second direction is The direction is preferably along a virtual line connecting the second magnetic detection element.

  A multidirectional input device according to the present invention includes the position detection system. According to this configuration, since the magnetic field insensitive region can be formed, the magnetic field generating component can be arranged in the magnetic field insensitive region X. For this reason, the multidirectional input device provided with this position detection system can improve the design freedom of the product (mobile device) to be mounted, and can reduce the size of the product (mobile device) to be mounted.

  The portable device of the present invention is a portable device having the multi-directional input device, wherein a magnetic field generating component is mounted in a region between the first magnetic detection element and the third magnetic detection element. It is characterized by.

  A portable device of the present invention is a portable device having the multidirectional input device, wherein a switch portion is formed in a region between magnetic detection elements.

  The position detection system of the present invention includes first to third magnetic detection elements mounted on a substrate, a magnet disposed on the substrate and movable with respect to the substrate, and the first magnetic detection element. And a control means for obtaining an output in the first direction by an output difference of the second magnetic detection element, and obtaining an output in the second direction by an output difference of the second magnetic detection element and the third magnetic detection element; The first magnetic detection element and the third magnetic detection element are arranged at symmetrical positions with respect to the magnet, and the second magnetic detection element includes the first magnetic detection element, Since it is arranged at the midpoint position in the virtual arc connecting the second magnetic detection element and the third magnetic detection element, the influence of disturbance from the magnetic field generating component Y can be reduced.

It is a figure for demonstrating the position detection system which concerns on embodiment of this invention. 1 is a circuit diagram of a position detection system according to an embodiment of the present invention. It is a figure for demonstrating the position detection method in the position detection system which concerns on embodiment of this invention. It is a figure for demonstrating the position detection capability of the multidirectional input device which concerns on embodiment of this invention. It is a figure which shows the mobile telephone which has a multidirectional input device provided with the position detection system which concerns on embodiment of this invention. It is a figure which shows the conventional multidirectional input device. It is a figure for demonstrating disorder of the output by the disturbance of the conventional multidirectional input device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram for explaining a position detection system according to an embodiment of the present invention. The position detection system 1 shown in FIG. 1 includes a substrate 11 and a slide magnet 13 disposed above the substrate 11. On the substrate 11, magnetic detection elements 12A to 12C and a signal processing element (signal processing circuit) 15 are mounted. An electrode pad 14 is formed on the substrate 11 for electrical connection with other components.

  In the substrate 11, the slide magnet 13 is disposed at the center, and the magnetic detection elements 12 </ b> A to 12 </ b> C are disposed around the slide magnet 13. Here, the sliding magnet 13 is a four-pole circular magnet, and is configured such that the polarity changes every 90 °. And magnetic detection element 12A-12C is arrange | positioned in the area | region corresponding to three magnetic pole area | regions among four magnetic pole area | regions. That is, of the magnetic detection elements 12A to 12C, the magnetic detection elements 12A and 12C are arranged at symmetrical positions around the slide magnet 13, and the magnetic detection element 12B is a virtual arc 16 connecting the magnetic detection elements 12A to 12C. Is located at the midpoint position. Therefore, no magnetic detection element is arranged in the region X corresponding to one magnetic pole region.

  As the magnetic detection elements 12A to 12C, magnetoresistive elements such as spin valve type GMR (Giant Magneto Resistive) elements and spin valve type TMR (Tunnel Magneto Resistive) elements can be used. As shown in FIG. 2, the magnetic detection elements 12 </ b> A to 12 </ b> C form a bridge circuit (here, the magnetic detection element 12 </ b> B is common). In addition, each of the magnetic detection elements 12A to 12C forms a half bridge with a magnetoresistive effect element (element A to element C) and a fixed resistance element (resistance A to resistance C), and outputs the result ( V1-V3).

  The sliding magnet 13 is configured to be movable with respect to the substrate. When this position detection system is used for a multidirectional input device, the slide magnet 13 moves relative to the substrate 11 by operating an operating body integrated with the slide magnet 13. For example, the operating body mainly includes a slide magnet, an annular coil spring that returns the slide magnet to the origin position when the slide magnet is moved by the slide operation, and an anti-rotation mechanism that prevents the slide magnet from rotating. It is configured to move with respect to the substrate 11. This configuration is disclosed in Japanese Patent Application Laid-Open No. 2005-310670 filed on Apr. 23, 2004 by the present applicant. Include all that here. As the slide magnet 13, a neodymium magnet, a ferrite magnet, a samarium cobalt magnet, or the like can be used.

  The signal processing circuit 15 which is a control means is connected to the magnetic detection elements 12A to 12C, and outputs of the magnetic detection elements 12A to 12C are sent to the signal processing circuit 15. The signal processing circuit 15 obtains a position detection output in a specific direction from the outputs of the magnetic detection elements 12A to 12C. That is, the signal processing circuit 15 obtains the output in the first direction based on the output difference between the magnetic detection element 12A and the magnetic detection element 12B, and obtains the output in the second direction based on the output difference between the magnetic detection element 12B and the magnetic detection element 12C. Here, as shown in FIG. 3, the first direction is the Y-axis direction along the imaginary line connecting the magnetic detection element 12 </ b> A and the magnetic detection element 12 </ b> C, and the second direction is the slide magnet 13 and the magnetic field. This is the X-axis direction along an imaginary line connecting the detection element 12B.

When position detection is performed by the signal processing circuit 15, first, the magnetic field strength applied to each of the magnetic detection elements 12A to 12C is calculated. For example, for the magnetic detection element 12A, assuming that the slide magnet 13 has a stroke of ± 1.5 mm, the X magnetic field component and the Y magnetic field component applied to the element position of the magnetic detection element 12A are calculated. After calculating the magnetic field component, the magnetic field angle at each position is calculated from the three-square theorem. When the magnetic field angle is obtained, the resistance value of the magnetoresistive element (GMR element), which is a magnetic detection element, can be calculated.
R = Rc + ΔMR / 200 × Rc / (1 + ΔMR / 200) × cos θ
At this time, Rc = 10000 [Ω] and ΔMR = 10.25%.
The resistance value R calculated here is the resistance value R1 of the magnetic detection element 12A. The resistance value of the magnetic detection element 12B is R2, and the resistance value of the magnetic detection element 12C is R3.

Next, an output value is calculated using the resistance value. As described above, since this sensor is a half bridge of one GMR element and one fixed resistance element, the output (V1) is obtained by the following equation. Here, Vdd is 3V.
V1 = R1 (R1 + Rc) × Vdd
The output V1 calculated here is the output of the magnetic detection element 12A. The output of the magnetic detection element 12B is V2, and the output of the magnetic detection element 12C is V3.

  In this way, the output V1 of the magnetic detection element 12A can be calculated. Similarly, the output V2 of the magnetic detection element 12B and the output V3 of the magnetic detection element 12C are also calculated. Thereafter, an X-axis output and a Y-axis output are calculated from the three differential outputs, and a position detection result is output. In this case, the X-axis output is a differential output of the output V1 and the output V2, and the Y-axis output is a differential output of the output V3 and the output V2.

  A position detection system in which the magnetic detection elements 12A to 12C and the signal processing element 15 are mounted at the arrangement positions as shown in FIG. 1 and the slide magnets 13 are arranged is produced. The slide magnets 13 are ± 1.5 mm. The position detection result in the case of a stroke was obtained as described above. The result is shown in FIG. As can be seen from FIG. 4, the position could be accurately detected. As described above, in the position detection system according to the present invention, since the region X shown in FIG. 1 is a magnetic field insensitive region, even if a magnetic field generating component is arranged in this magnetic field insensitive region, the influence of disturbance of the magnetic field generating component is reduced. can do. In addition, in the conventional position detection using a 4-pole circular magnet, it is necessary to provide four magnetic detection elements, but in the position detection system according to the present invention, three magnetic detection elements may be used, The number of parts can also be reduced.

  Next, a multidirectional input device equipped with the position detection system of the present invention will be described. Such a multidirectional input device is mounted on a mobile device, for example, a mobile phone. FIG. 5 is a diagram showing a mobile phone provided with the multidirectional input device according to the embodiment of the present invention. As shown in FIG. 5, the multidirectional input device 22 according to the present invention is attached to the operation panel 21 of the mobile phone 2. The position detection system in the multidirectional input device 22 is mounted on the mobile phone 2 so that the longitudinal direction of the device shown in FIGS. 1 and 3 is along the longitudinal direction of the device shown in FIG. For this reason, no element exists in the region 17 between the magnetic detection elements 12A to 12C shown in FIG. For this reason, in the mobile phone, the switch unit 23 can be provided in an area corresponding to the area 17 in the position detection system. Thereby, the position which provides the magnetic detection elements 12A-12C and the switch part 23 does not overlap. In this case, since the position detection output is as shown in FIG. 4, the region 17 can be out of the output range, and even if the switch unit 23 is provided in the region 17, the position detection is affected. Absent.

  In this position detection system, as shown in FIGS. 1 and 3, a magnetic field insensitive region is formed in the region X (the region between the magnetic detection element 12A and the magnetic detection element 12C). Magnetic field generating components can be arranged in the region X. That is, a magnetic field generating component can be mounted in the region 24 of the mobile phone 2. For this reason, the multidirectional input device provided with the position detection system can improve the degree of freedom of design of the mobile phone that is the mounted product, and can reduce the size of the mobile phone that is the mounted product.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications. For example, in the above-described embodiment, a case where three magnetic detection elements are used using a quadrupole magnet is described. The present invention can be similarly applied to other cases where the detection elements are arranged so that the magnetic field insensitive region is formed. In addition, the materials, connection relations, dimensions, manufacturing methods, and the like in the above embodiments can be changed as appropriate. In addition, the present invention can be implemented with appropriate modifications without departing from the scope of the present invention.

  The present invention can be suitably used for a position detection system for a multidirectional input device of a mobile phone.

DESCRIPTION OF SYMBOLS 1 Position detection system 2 Cellular phone 11 Board | substrate 12A-12C Magnetic detection element 13 Slide magnet 14 Electrode pad 15 Signal processing element (signal processing circuit)
16 Virtual arc 17, 24 Magnetic field insensitive area 21 Operation panel 22 Multidirectional input device 23 Switch part

Claims (6)

  First to third magnetic detection elements mounted on a substrate, a magnet disposed on the substrate and movable with respect to the substrate, the first magnetic detection element and the second magnetic detection element Control means for obtaining an output in the first direction by an output difference of the second magnetic detection element and obtaining an output in the second direction by an output difference of the second magnetic detection element and the third magnetic detection element. The magnetic detection element and the third magnetic detection element are arranged symmetrically with respect to the magnet, and the second magnetic detection element includes the first magnetic detection element, the second magnetic detection element, and A position detection system, wherein the position detection system is arranged at a midpoint position in a virtual arc connecting the third magnetic detection elements.   The sliding magnet is a four-pole circular magnet, and is configured such that the polarity changes every 90 °, and the first magnetic detection element is arranged in a region corresponding to three magnetic pole regions of the four magnetic pole regions. The position detection system according to claim 1, wherein the second magnetic detection element and the third magnetic detection element are arranged.   The first direction is a direction along a virtual line connecting the first magnetic detection element and the third magnetic detection element, and the second direction is a distance between the magnet and the second magnetic detection element. The position detection system according to claim 1, wherein the position detection system is a direction along a virtual line to be connected.   A multidirectional input device comprising the position detection system according to any one of claims 1 to 3.   5. A portable device having the multidirectional input device according to claim 4, wherein a magnetic field generating component is mounted in a region between the first magnetic detection element and the third magnetic detection element. Portable device.   5. A portable device having the multidirectional input device according to claim 4, wherein a switch portion is formed in a region between the magnetic detection elements.

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