JP2010156543A - Magnetic detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detecting device, which can have a wider detecting range for an external magnetic field than that of the prior art and which can make a dipole detection highly precisely. <P>SOLUTION: A first magneto-resistance effect element and a second magneto-resistance effect element are formed to have a hard bias layer so that a fixed magnetic layer and a free magnetic layer are made orthogonal in their magnetizing direction thereby to establish a relation between an external magnetic field H and an output value (or a differential potential), as shown in Fig.1. The range for detecting the external magnetic field H can be set wider than that of the prior art. Moreover, there arises no hysteresis, and the output value is straight but not blunt even for the zero external magnetic field, so that the external magnetic field H can be detected highly precisely all over the detecting range. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic detection device capable of widening the detection range of an external magnetic field and capable of detecting bipolar with high accuracy as compared with the conventional case.

  Bipolar detection is possible in the magnetic detection devices described in Patent Documents 1 and 2 below. That is, even if an external magnetic field in the (+) direction and an external magnetic field in the (−) direction opposite to the (+) direction are acted, both external magnetic fields can be detected.

In the inventions described in Patent Documents 1 and 2, the magnetoresistive effect element having the structure shown in FIG. 2 of Patent Documents 1 and 2 is used, and a current bias magnetic field is further applied, so that FIG. In the RH curve of FIG. 7 shown in FIG. 2, the linear regions L1 and L2 are used as actual detection regions.
JP 2006-19383 A JP-A-2005-236134

  However, in the configuration of the magnetic detection device disclosed in Patent Documents 1 and 2, since the linear regions L1 and L2 are external magnetic field detection ranges, the detection range cannot be set wide.

  Further, if the current bias magnetic field is weakened and the linear regions L1 and L2 are to be widened, for example, the portion where the resistance change rate (ΔR / R) near zero external magnetic field shown in FIG. , L2 enters, and there is a problem that high-precision detection cannot be performed.

  Accordingly, the present invention is to solve the above-described conventional problems, and in particular, to provide a magnetic detection device capable of widening the detection range of the external magnetic field and capable of bipolar detection with high accuracy as compared with the related art. It is aimed.

The magnetic detection device in the present invention is
Magnetoresistance in which the electrical resistance changes with respect to the external magnetic field, stacked from the bottom in the order of the pinned magnetic layer, nonmagnetic material layer, and free magnetic layer, or from the bottom in the order of the free magnetic layer, nonmagnetic material layer, and pinned magnetic layer A first magnetoresistive effect element and a second magnetoresistive effect element utilizing the effect,
Each of the first magnetoresistive element and the second magnetoresistive element includes a bias layer for aligning the magnetization direction of the free magnetic layer in a direction perpendicular to the magnetization direction of the pinned magnetic layer in the absence of a magnetic field. Provided,
A first output value based on a resistance value that changes with respect to a change in magnetic field strength of an external magnetic field of the first magnetoresistive effect element, and a resistance that changes with respect to a change in magnetic field strength of an external magnetic field of the second magnetoresistive effect element Both of the second output values based on the value include a linear region that linearly changes from the external magnetic field side in the (+) direction to the external magnetic field side in the (−) direction, and from the no magnetic field state to the external in the (+) direction. The increasing / decreasing tendency of the first output value when the magnetic field is increased and the increasing / decreasing tendency of the second output value when the external magnetic field in the (−) direction is increased from the no magnetic field state are the same tendency. It is characterized by this.

  With the above configuration, the detection range of the external magnetic field can be set wider than before, and bipolar detection can be performed with high accuracy.

  In the present invention, it is preferable that a common threshold is set for the first output value and the second output value. Thereby, in this invention, a circuit structure can be simplified and size reduction of an apparatus can be accelerated | stimulated.

  In the present invention, the first magnetoresistive effect element and the second magnetoresistive effect element can be formed with the same film configuration, and the manufacture of the magnetic detection device can be facilitated.

  In the present invention, the detection range of the external magnetic field can be set wider than before, and bipolar detection can be performed with high accuracy.

  1 and 2 are graphs and diagrams showing the relationship between the external magnetic field H and the output value V (differential potential) based on the resistance values of the first magnetoresistive element and the second magnetoresistive element of this embodiment. 3 and 4 are RH curves of the first magnetoresistive effect element and the second magnetoresistive effect element of the present embodiment, and FIG. 5 is a diagram of the first magnetoresistive effect element and the second magnetoresistive effect element of the present embodiment. FIG. 6 and FIG. 7 are circuit configuration diagrams of the magnetic detection device of this embodiment, FIG. 8 is a plan view of the folding cellular phone opened, and FIG. 9 is the folding type shown in FIG. FIG. 10 is a side view of the foldable mobile phone showing a state in the middle of closing the foldable mobile phone from the state of FIG. 9, and FIG. 11 is a side view of the completely foldable mobile phone from the state of FIG. FIG. 12 is a side view of the closed state seen from the side, and FIG. 12 shows the folded state shown in FIG. 13 is a partial cross-sectional view of the cellular phone taken along the line AA and viewed from the direction of the arrow. FIG. 13 is a perspective view of the folding cellular phone showing a state in which the display housing is reversed from the state of FIG. Fig. 15 is a plan view of a folding mobile phone showing the state in which the front and back surfaces of the display casing are reversed. Fig. 15 is a partial cross-sectional view at the same position as Fig. 12 when the folding mobile phone is closed from the state shown in Fig. 14. .

  The X1 and X2 directions used in each figure are the horizontal direction, the Y1 and Y2 directions are the vertical direction, the Z direction is the height direction, and each direction is orthogonal to the remaining two directions.

  As shown in FIG. 6, the magnetic detection device 20 of this embodiment is provided with two magnetoresistive elements (GMR elements) 23 and 27.

  As shown in FIG. 5, the magnetoresistive elements 23 and 27 are formed on the substrate 12 from below, for example, the underlayer 17, the antiferromagnetic layer 13, the pinned magnetic layer 14, the nonmagnetic material layer 15, the free magnetic layer 16, and the like. The protective layers 18 are stacked in this order. The underlayer 17 is made of Ta, the antiferromagnetic layer 13 is made of IrMn, the pinned magnetic layer 14 is made of CoFe, the nonmagnetic material layer 15 is made of Cu, the free magnetic layer 16 is made of NiFe, and the protective layer 18 is made of Ta. As shown in FIG. 4, hard bias layers 11 are provided on both sides of the laminate from the base layer 17 to the protective layer 18. The hard bias layer 11 is made of, for example, CoPt.

  As shown in FIG. 5, the magnetization 14a of the pinned magnetic layer 14 of the magnetoresistive elements 23 and 27 is pinned in the X2 direction by an exchange coupling magnetic field (Hex) generated at the interface with the antiferromagnetic layer 13. . The magnetization 16a of the free magnetic layer 16 is aligned in the Y1 direction by the bias magnetic field from the hard bias layer 11. As shown in FIG. 5, the magnetization 14a of the pinned magnetic layer 14 and the magnetization 16a of the free magnetic layer 16 are orthogonal to each other in the absence of a magnetic field.

  The magnetoresistive effect elements 23 and 27 shown in FIG. 5 are GMR elements utilizing the giant magnetoresistive effect (GMR effect), but the tunnel type magnetoresistive effect in which the portion of the nonmagnetic material layer 15 is formed of an insulating layer. A TMR element utilizing (TMR effect) may be used. Further, unlike FIG. 5, the base layer 17, the free magnetic layer 16, the nonmagnetic material layer 15, the pinned magnetic layer 14, the antiferromagnetic layer 13, and the protective layer 18 may be stacked in this order from the bottom.

  FIG. 3 shows RH curves of the magnetoresistive effect elements 23 and 27. For example, the external magnetic field (+ H) in the (+) direction shown on the horizontal axis is the X1 direction in the figure, and the external magnetic field (−H) in the (−) direction is the X2 direction in the figure. As shown in FIG. 3, the magnetoresistive effect elements 23 and 27 are provided with the hard bias layer 11 and a bias magnetic field is applied, thereby eliminating the hysteresis (even if it occurs), as shown in FIG. A linear region 19 that linearly changes from the external magnetic field (+ H) side in the (+) direction to the external magnetic field (−H) side in the (−) direction is provided. The inclination angle with respect to the horizontal axis (external magnetic field H) of the region where the resistance value R changes with respect to the external magnetic field H as in the linear region 19 is smaller than that in the case where the hard bias layer 11 is not formed, and will be described later. In addition, the detection range of the external magnetic field H can be widened.

  As shown in FIG. 3, the magnitude of the external magnetic field H when the resistance value R of the magnetoresistive elements 23 and 27 reaches the maximum resistance value R1 or the minimum resistance value R2 is the same as the anisotropic magnetic field Hk1. For example, by changing the magnitude of the bias magnetic field of the hard bias layer 11, the inclination of the linear region 19 can be changed as shown in FIG. 3, and as a result, the magnitude of the anisotropic magnetic field Hk1 is changed to Hk2. Can be made. For example, in the present embodiment, the anisotropic magnetic field Hk1 can be set to 50 to 500 Oe.

  As shown in FIG. 6, the magnetic detection device 20 of the present embodiment includes a resistance element unit 21 and an integrated circuit (IC) 22.

  The resistance element section 21 includes a first series circuit 26 in which a first magnetoresistance effect element 23 and a first fixed resistance element 24 are connected in series via a first output section 25, and a second magnetoresistance effect element. A second series circuit 30 is provided in which 27 and the second fixed resistance element 28 are connected in series via a second output unit 29.

  In the integrated circuit 22, a third series circuit 34 in which a third fixed resistance element 31 and a fourth fixed resistance element 32 are connected in series via a third output unit 33 is provided.

  The third series circuit 34 forms a bridge circuit with the first series circuit 26 and the second series circuit 30 as a common circuit. Hereinafter, a bridge circuit formed by connecting the first series circuit 26 and the third series circuit 34 in parallel is referred to as a first bridge circuit BC1, and the second series circuit 30 and the third series circuit 34 are connected in parallel. This bridge circuit is referred to as a second bridge circuit BC2.

  As shown in FIG. 6, in the first bridge circuit BC1, the first magnetoresistance effect element 23 and the fourth fixed resistance element 32 are connected in parallel, and the first fixed resistance element 24 and the first fixed resistance element 24 are connected to each other. 3 fixed resistance elements 31 are connected in parallel. In the second bridge circuit BC2, the second magnetoresistance effect element 27 and the third fixed resistance element 31 are connected in parallel, and the second fixed resistance element 28 and the fourth fixed resistance element 32 are connected to each other. Are connected in parallel.

  As shown in FIG. 6, the integrated circuit 22 is provided with an input terminal (power source) 39, a ground terminal 42, and two external output terminals 40 and 41. The input terminal 39, the ground terminal 42, and the external output terminals 40, 41 are electrically connected to terminal portions on the device side (not shown) by wire bonding, die bonding, or the like.

  A line 50 connected to the input terminal 39 and a line 51 connected to the ground terminal 42 are electrodes provided at both end portions of the first series circuit 26, the second series circuit 30, and the third series circuit 34. Connected to each of them.

  As shown in FIG. 6, a single differential amplifier 35 is provided in the integrated circuit 22, and the third series circuit 34 of the third series circuit 34 is connected to either the + input section or the −input section of the differential amplifier 35. An output unit 33 is connected. The first output section 25 of the first series circuit 26 and the second output section 29 of the second series circuit 30 are connected to the input section of a first switch circuit (first connection switching section) 36, respectively, and the first switch circuit The output unit 36 is connected to either the − input unit or the + input unit of the differential amplifier 35 (the input unit on the side where the third output unit 33 is not connected).

  As shown in FIG. 6, the output section of the differential amplifier 35 is connected to a Schmitt trigger type comparator 38, and the output section of the comparator 38 is an input section of a second switch circuit (second connection switching section) 43. Furthermore, the output side of the second switch circuit 43 is connected to the first external output terminal 40 and the second external output terminal 41 via the two latch circuits 46 and 47 and the FET circuits 54 and 55, respectively.

  Further, as shown in FIG. 6, a third switch circuit 48 is provided in the integrated circuit 22. The output part of the third switch circuit 48 is connected to a line 51 connected to the ground terminal 42, and one end of the first series circuit 26 and the second series circuit 30 is connected to the input part of the third switch circuit 48. Are connected.

  Further, as shown in FIG. 6, an interval switch circuit 52 and a clock circuit 44 are provided in the integrated circuit 22. When the switch of the interval switch circuit 52 is turned off, the power supply to the integrated circuit 22 is stopped. The on / off of the switch of the interval switch circuit 52 is interlocked with the clock signal from the clock circuit 44, and the interval switch circuit 52 has a power saving function for intermittently energizing.

  The clock signal from the clock circuit 44 is also output to the first switch circuit 36, the second switch circuit 43, and the third switch circuit 48. When receiving the clock signal, the first switch circuit 36, the second switch circuit 43, and the third switch circuit 48 are controlled so as to divide the clock signal and perform the switch operation with a very short cycle. For example, when one pulse of the clock signal is several tens of milliseconds, the switching operation is performed every several tens of micrometers.

  As described in FIG. 5, the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 have the same film configuration. Here, the same film configuration indicates a state in which the directions of the magnetizations 14a and 16a of the pinned magnetic layer 14 and the free magnetic layer 16 are not only the same, but also the laminated structure is the same. Here, in the present embodiment, the first magnetoresistive element 23 shown in FIG. 6 is used as an element for detecting the external magnetic field (+ H) in the (+) direction, and the second magnetoresistive element 27 is used in the (−) direction. It is used as an element for detecting an external magnetic field (-H).

  As shown in FIG. 6, the first magnetoresistance effect element 23 is connected to the ground terminal 42 side, and the second magnetoresistance effect element 27 is connected to the input terminal 39 side. Accordingly, the first output value (differential potential) V1 output from the first bridge circuit BC1 including the first magnetoresistance effect element 23 and the second bridge circuit BC2 including the second magnetoresistance effect element 27 are output. The first output value (differential potential) V2 appears in a crossed manner as shown in FIG.

  Both the first output value V1 and the second output value V2 include linear regions 8 and 9 that linearly change from the external magnetic field (+ H) side in the (+) direction to the external magnetic field (−H) side in the (−) direction. .

  For example, the linear linear regions 8 and 9 cross at the position of the external magnetic field zero, and the region of the external magnetic field (+ H) in the (+) direction in the linear region 8 of the first output value V1 and the second output value V2. A wide range of the external magnetic field H from the position + H1 to the position −H1 shown in FIG. 1 is set as the detection range by combining the detection area of the external magnetic field (−H) in the (−) direction in the linear area 9 of FIG. Is possible.

  As shown in FIG. 1, the threshold value LV1 for switching the ON / OFF signal is set by the comparator 38. For example, when an output (differential potential) exceeding the threshold value LV1 is obtained, the ON signal is set to the threshold value. When an output (differential potential) lower than LV1 is obtained, an OFF signal is generated. A plurality of threshold values may be set, but in the present embodiment, only one threshold value is set.

  As shown in FIG. 1, when the external magnetic field (+ H) in the (+) direction is increased from the no magnetic field state, the first output value V1 increases, and similarly, the external magnetic field in the (−) direction from the no magnetic field state. When (−H) is increased, the second output value V2 increases. Further, when the external magnetic field (+ H) in the (+) direction is increased from the no magnetic field state, the first output value V1 decreases, and similarly, the external magnetic field (−H) in the (−) direction from the no magnetic field state. When increased, the second output value V2 may decrease. As described above, when the external magnetic field (+ H) in the (+) direction is increased from the no magnetic field state, the increase / decrease tendency of the first output value V1 and the external magnetic field (−H) in the (−) direction from the no magnetic field state. Since the increase / decrease tendency of the second output value V2 when increasing is the same tendency, the detection region on the (+) direction external magnetic field (+ H) side and the (−) direction external magnetic field (−H) side The threshold value LV1 for generating the ON / OFF signal switching signal in both of the detection areas can be made common to the first output value V1 and the second output value V2. As shown in FIG. 1, the ON / OFF signal is switched when the external magnetic field (+ H) in the (+) direction is at + H2, and the external magnetic field (−H) in the (−) direction is ON at −H2. / OFF signal is switched.

  FIG. 6 shows a state in which the first bridge circuit BC1 and the first external output terminal 40 are connected. From the first external output terminal 40, the magnetic field intensity changes in the external magnetic field (+ H) in the (+) direction. An ON signal or an OFF signal is output.

  On the other hand, FIG. 7 shows a state in which the second bridge circuit BC2 and the second external output terminal 41 are connected, and the second external output with respect to the change in the magnetic field strength of the external magnetic field (−H) in the (−) direction. An ON signal or an OFF signal is output from the terminal 41.

  In the circuit configurations of FIGS. 6 and 7, since the ON / OFF switching signal is output from both the first external output terminal 40 and the second external output terminal 41, the ON signal is output from either of the external output terminals 40, 41, for example. It is possible to determine whether the external magnetic field (+ H) in the (+) direction or the external magnetic field (−H) in the (−) direction.

  On the other hand, for example, the second switch circuit 43 may not be provided, and the output may be performed from only one of the first external output terminal 40 and the second external output terminal 41. In such a case, however, the direction of the external magnetic field H cannot be detected.

  The first fixed resistance element 24, the second fixed resistance element 28, the third fixed resistance element 31, and the fourth fixed resistance element 32 shown in FIGS. 6 and 7 are all set to the same fixed resistance value. When the resistance value of the first fixed resistance element 24 is set to a resistance value different from the resistance values of the second fixed resistance element 28, the third fixed resistance element 31, and the fourth fixed resistance element 32, the entire first output value V1 is shown in FIG. It can be moved up and down on the graph shown in FIG. In FIG. 2, for example, the entire first output value V1 is lowered. When the threshold LV1 is not different from that in FIG. 1, the ON / OFF signal switching in the fluctuation of the first output value V1 is when the external magnetic field (+ H) in the (+) direction is + H3, and can be different from that in FIG. It becomes.

  Further, for example, by changing the resistance value of the second fixed resistance element 28, the second output value V2 can be varied up and down on the graph shown in FIG.

  The detection range of the external magnetic field H shown in FIG. 1 is, for example, an interlayer coupling magnetic field that acts between the fixed magnetic layer 14 and the free magnetic layer 16 or changes the magnitude of the anisotropic magnetic field Hk1 shown in FIG. It can be changed by changing the size of Hin. The interlayer coupling magnetic field Hin can be changed, for example, by changing the film thickness of the nonmagnetic material layer 15.

  On the RH graph, the interlayer coupling magnetic field Hin appears as the magnitude of the external magnetic field H when it becomes an intermediate resistance value between the maximum resistance value R1 and the minimum resistance value R2 of the magnetoresistive effect element. In FIG. 3, the interlayer coupling magnetic field Hin is zero, but in the form shown in FIG. 4, the absolute values of the interlayer coupling magnetic fields Hin1 and Hin2 appear as values larger than zero. When the magnitudes of the interlayer coupling magnetic fields Hin1 and Hin2 change, the RH curve moves in the horizontal axis (external magnetic field H) direction. In the form shown in FIG. 4, for example, the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 are formed separately, and the absolute value of the interlayer coupling magnetic field Hin1 generated in the first magnetoresistive effect element 23, The absolute value of the interlayer coupling magnetic field Hin2 generated in the second magnetoresistance effect element 27 is set to be the same value. In FIG. 4, the magnetization 14 a of the pinned magnetic layer 14 of the first magnetoresistance effect element 23 is pinned in the same X2 direction as in FIG. 5, and the magnetization 14 a of the pinned magnetic layer 14 of the second magnetoresistance effect element 27 is It is fixed in the X1 direction, which is the opposite direction to FIG. When the X1 direction shown in the figure is set as the direction of the external magnetic field (+ H) in the (+) direction and the X2 direction shown in the figure is set as the direction of the external magnetic field (−H) in the (−) direction, the RH curve shown in FIG. 4 is obtained. . When the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 having the RH curve of FIG. 4 are formed, for example, in the circuit configuration shown in FIGS. 6 and 7, the second magnetoresistive effect element 27 and The second fixed resistance element 28 is replaced and disposed.

  In the present embodiment, by obtaining the relationship between the external magnetic field H and the output value (differential potential) shown in FIG. 1, the detection range of the external magnetic field H can be set wider than in the prior art, and there is no hysteresis. Since the output value is linear and not dull even near zero, the external magnetic field H can be detected with high accuracy over the entire detection range.

  Further, in this embodiment, even if elements having the same film configuration are used for the first magnetoresistive element 23 and the second magnetoresistive element 27, for example, by switching the resistance value of the fixed resistor element, switching of ON / OFF is performed. The magnitude of the external magnetic field H at the time can be freely adjusted separately in the detection region of the external magnetic field (+ H) in the (+) direction and the detection region of the external magnetic field (−H) in the (−) direction. . Further, since the common threshold LV1 can be set for the first output value V1 and the second output value V2, the circuit configuration can be simplified and the magnetic detection device 20 can be downsized.

  The magnetic detection device 20 in the present embodiment can be a foldable mobile phone 1 shown below, for example.

  The foldable mobile phone 1 according to this embodiment shown in FIGS. 8 and 9 includes a display housing 2, an operation housing 3, and a connecting member 4 that connects the display housing 2 and the operation housing 3. Configured.

  When the foldable mobile phone 1 is opened as shown in FIG. 8, the display surface 2 a provided with the display screen 5 such as a liquid crystal display of the display housing 2 and various operation buttons 6 of the operation housing 3 are provided. The arranged operation surface 3a faces the same outside.

  A speaker 45 is provided on the display surface 2 a of the display housing 2, and a microphone 7 is provided on the operation surface 3 a of the operation housing 3.

  As shown in FIGS. 8 and 9, the connecting member 4 includes a hinge portion 49 fixed to the operation housing 3 and a first rotating shaft 50 extending in a lateral direction (X1-X2 direction in the drawing) of the hinge portion 49. And an intermediate portion 10 that rotates together with the display housing 2 in the opening / closing direction about the first rotation shaft 50.

  The intermediate portion 10 has a second direction at the center in the lateral direction (X1-X2 direction) of the intermediate portion 10 in a direction orthogonal to the first rotation shaft 50 (Y1-Y2 direction in the drawing). A rotation shaft 56 is provided, and the display housing 2 is connected to the second rotation shaft 56. The display housing 2 is supported to be reversible around the second rotation shaft 56. Therefore, in the foldable mobile phone 1 of this embodiment, the front and back surfaces of the display housing 2 can be reversed as shown in FIG. 13 from the normal use state of FIG. 9 to shift to the reversed state shown in FIG.

  As shown in FIG. 8, when the longitudinal direction of the folded mobile phone 1 in the opened state is arranged in a direction parallel to the vertical direction (Y direction in the drawing), the lateral direction (X direction in the drawing) of the folded mobile phone 1 is arranged. For example, one magnet 53 is arranged inside the display housing 2 on the center line BB extending in the vertical direction (Y direction in the drawing).

  As shown in FIG. 8, the magnet 53 is arranged such that the N pole and the S pole are oriented in the horizontal direction (X1-X2 direction in the drawing).

  A magnetic detection device 20 of the present embodiment is provided inside the operation housing 3 on the center line BB.

  In this embodiment, the magnetic detection device 20 is arranged at a position facing the magnet 53 in the height direction (Z direction in the drawing) when the display housing 2 and the operation housing 3 shown in FIG. 11 are closed. The Alternatively, the magnetic detection device 20 may be disposed at a position shifted from the magnet 53 in the X1-X2 direction.

  Until the foldable mobile phone 1 is closed as shown in FIGS. 10 to 11, the horizontal magnetic field acting on the magnetic detection device 20 from the magnet 53 gradually increases. At this time, the external magnetic field H in the X1 direction, that is, the external magnetic field (+ H) in the (+) direction acts on the first magnetoresistive element 23 and the second magnetoresistive element 27, and the (+) direction As the magnetic field intensity of the external magnetic field (+ H) changes, both the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 change in resistance.

  Based on the resistance change of the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27, the first output value V1 and the second output value in the region of the external magnetic field (+ H) in the (+) direction shown in FIG. V2 is obtained.

  As shown in FIG. 1, when the external magnetic field (+ H) in the (+) direction gradually increases, the first output value V1 gradually increases along the linear region 8 and eventually becomes a threshold value. Beyond LV1, the ON / OFF signal is switched.

  Next, the front and back surfaces of the display housing 2 are reversed from the state shown in FIG. 9 to the flat state shown in FIG. 14, and the display housing 2 and the operation housing 3 are restarted from the state shown in FIG. And fold.

  FIG. 15 shows a state in which the display housing 2 and the operation housing 3 are completely closed by inverting the front and back surfaces of the display housing 2. As shown in FIG. A horizontal magnetic field H in the (−) direction acts from 53. That is, the direction of the horizontal magnetic field H is reversed as compared with the case of FIG.

  When the display housing 2 and the operation housing 3 are folded as shown in FIG. 15 from the state of FIG. 14, an external magnetic field (−H) in the (−) direction gradually emitted from the magnet 53 is applied to the magnetic detection device 20. By acting, both the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 change in resistance.

  Based on the resistance change of the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27, the first output value V1 and the second output in the region of the external magnetic field (-H) in the (-) direction shown in FIG. The value V2 is obtained.

  As shown in FIG. 1, when the external magnetic field (-H) in the (-) direction gradually increases, the second output value V2 gradually increases along the linear region 9, and eventually. The ON / OFF signal is switched over the threshold value LV1.

  By detecting which output signal of the first external output terminal 40 or the second external output terminal 41 is switched from ON to OFF (or from OFF to ON), the surface of the display housing 2 of the foldable mobile phone 1 is displayed. It is possible to know whether the opening / closing detection is performed in a state where the back surface is not reversed, or whether the opening / closing detection is performed in a state where the front and back surfaces of the display housing 2 are reversed.

  Further, as shown in FIGS. 12 and 15, when the foldable mobile phone 1 is closed without reversing the front and back surfaces of the display housing 2, and when the foldable mobile phone is folded with the front and back surfaces of the display housing 2 reversed. When the telephone 1 is closed, the distances D1 and D2 between the magnet 53 and the magnetic detection device 20 are different. Therefore, as described in FIG. 2, the magnitude of the external magnetic field H (+ H3) at which the first output value V1 reaches the threshold value LV1, and the magnitude (−H2) of the external magnetic field H at which the second output value V2 reaches the threshold value LV1. The folding cellular phone 1 is closed with the front and back surfaces of the display housing 2 reversed, and the folding cellular phone 1 is closed with the front and back surfaces of the display housing 2 reversed. In some cases, adjustment can be made so that switching from ON to OFF (or OFF to ON) is performed at the same timing.

  In the present embodiment, bipolar detection can be obtained with two outputs in this way, or bipolar detection can be obtained with one output. In this case, particularly when detection of the direction of the external magnetic field H is not required, the circuit configuration can be simplified, which is preferable. By adopting bipolar detection, for example, the magnet 53 shown in FIG. 8 can detect the external magnetic field H not only when the magnet 53 shown in FIG. In addition, the direction of the magnet 53 has a degree of freedom, and the assembly workability can be improved.

  Although the folding mobile phone has been described as an embodiment in the above, the magnetic detection device 20 of the present embodiment can be applied to various electric appliances such as a game machine, a notebook personal computer, and a refrigerator other than the folding mobile phone. I can do it.

A first graph showing a relationship between an external magnetic field H and an output value V (differential potential) based on resistance values of the first magnetoresistive effect element and the second magnetoresistive effect element of the present embodiment; A second graph showing the relationship between the external magnetic field H and the output value V (differential potential) based on the resistance values of the first magnetoresistive element and the second magnetoresistive element of the present embodiment; RH curves of the first magnetoresistive element and the second magnetoresistive element of the present embodiment, RH curves of the first magnetoresistive element and the second magnetoresistive element of the embodiment different from FIG. Sectional drawing which shows the film | membrane structure of the 1st magnetoresistive effect element in this embodiment, and the 2nd magnetoresistive effect element, The circuit block diagram of the magnetic detection apparatus of this embodiment (The state where 1st bridge circuit BC1 and 1st external output terminal are connected) The circuit block diagram of the magnetic detection apparatus of this embodiment (The state where 2nd bridge circuit BC2 and 2nd external output terminal are connected), A plan view of a state in which the folding mobile phone is opened, FIG. 9 is a perspective view of the folding mobile phone shown in FIG. The side view of a folding-type mobile phone which shows the state in the middle of closing a folding-type mobile phone from the state of FIG. The side view which looked at the closed state of a completely folding cellular phone from the state of FIG. The fragmentary sectional view which cut | disconnected the foldable mobile telephone of the closed state shown in FIG. 11 from the AA line, and was seen from the arrow direction, The perspective view of the folding-type mobile phone which shows the middle state which reverses a display housing | casing from the state of FIG. A plan view of a foldable mobile phone showing a state in which the front and back surfaces of the display casing are reversed; The fragmentary sectional view in the same location as FIG. 12 when the foldable mobile phone is closed from the state of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Folding type mobile phone 2 Display case 3 Operation case 4 Connecting member 5 Display screen 6 Operation buttons 8, 9, 19 Linear region 10 Intermediate part 11 Hard bias layer 13 Antiferromagnetic layer 14 Fixed magnetic layer 15 Nonmagnetic material layer 16 Free magnetic layer 20 Magnetic detection device 21 Resistance element unit 22 Integrated circuit (IC)
23 First magnetoresistance effect element 24, 28, 31, 32 Fixed resistance element 27 Second magnetoresistance effect element 35 Differential amplifier 38 Comparator 39 Input terminal 40, 41 External output terminal 42 Ground terminal 53 Magnet V1 First output value V2 Second output value

Claims (3)

Magnetoresistance in which the electrical resistance changes with respect to the external magnetic field, stacked from the bottom in the order of the pinned magnetic layer, nonmagnetic material layer, and free magnetic layer, or from the bottom in the order of the free magnetic layer, nonmagnetic material layer, and pinned magnetic layer A first magnetoresistive effect element and a second magnetoresistive effect element utilizing the effect,
Both the first magnetoresistive element and the second magnetoresistive element have a bias layer for aligning the magnetization direction of the free magnetic layer in a direction perpendicular to the magnetization direction of the pinned magnetic layer in the absence of a magnetic field. Provided,
A first output value based on a resistance value that changes with respect to a change in magnetic field strength of an external magnetic field of the first magnetoresistive effect element, and a resistance that changes with respect to a change in magnetic field strength of an external magnetic field of the second magnetoresistive effect element Both of the second output values based on the value include a linear region that linearly changes from the external magnetic field side in the (+) direction to the external magnetic field side in the (−) direction, and from the no magnetic field state to the external in the (+) direction. The increasing / decreasing tendency of the first output value when the magnetic field is increased and the increasing / decreasing tendency of the second output value when the external magnetic field in the (−) direction is increased from the no magnetic field state are the same tendency. A magnetic detection device.   The magnetic detection device according to claim 1, wherein a common threshold is set for the first output value and the second output value.   The magnetic detection device according to claim 1, wherein the first magnetoresistive effect element and the second magnetoresistive effect element have the same film configuration.

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