JP7156432B2 - Position detection device, lens module and imaging device - Google Patents

Description

The present invention relates to a position detection device, a lens module, and an imaging device having a magnetic sensor.

Position detection devices using magnetic sensors have been proposed so far. The applicant of the present application has proposed, for example, a camera module provided with a position detection device (see Patent Document 1, for example). In this camera module, the position detection device detects the position of the lens that moves during focusing. Further, a lens driving device having a position detection magnet for detecting the movement position of the lens holding member and a magnetic detection member has also been proposed (see, for example, Patent Document 2).

JP 2019-082445 A International Publication No. 2018/051729

By the way, a position detection device using a magnetic sensor is required to have higher position detection accuracy.

Therefore, it is desired to provide a position detection device capable of exhibiting high detection accuracy.

A position detection device as an embodiment of the present invention has a magnetic sensor, a first magnetic field generator, and a second magnetic field generator. The first magnetic field generator includes a first magnet and a second magnet spaced apart from each other in a first direction and generates a first magnetic field. The second magnetic field generator generates a second magnetic field, and is provided movably along a second direction perpendicular to the first direction with respect to the first magnetic field generator and the magnetic sensor. In the first direction, the center position of the magnetic sensor is at a position other than the middle position between the first magnet and the second magnet in the area between the first magnet and the second magnet. The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing a first magnetic field along a plane perpendicular to the second direction and a second magnetic field along the plane, A change in the position of the magnetic field generator can be detected.

A lens module as one embodiment of the present invention includes a magnetic sensor, a first magnetic field generator, a second magnetic field generator, and a lens. The first magnetic field generator includes a first magnet and a second magnet spaced apart from each other in a first direction and generates a first magnetic field. The second magnetic field generator generates a second magnetic field, and is provided movably along a second direction perpendicular to the first direction with respect to the first magnetic field generator and the magnetic sensor. A lens is provided movably along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator. In the first direction, the center position of the magnetic sensor is at a position other than the middle position between the first magnet and the second magnet in the area between the first magnet and the second magnet. The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing a first magnetic field along a plane perpendicular to the second direction and a second magnetic field along the plane, A change in the position of the magnetic field generator can be detected.

An imaging device as an embodiment of the present invention has an imaging element and a lens module. The lens module has a magnetic sensor, a first magnetic field generator, a second magnetic field generator, and a lens. The first magnetic field generator includes a first magnet and a second magnet spaced apart from each other in a first direction and generates a first magnetic field. The second magnetic field generator generates a second magnetic field, and is provided movably along a second direction perpendicular to the first direction with respect to the first magnetic field generator and the magnetic sensor. A lens is provided movably along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator. In the first direction, the center position of the magnetic sensor is at a position other than the middle position between the first magnet and the second magnet in the area between the first magnet and the second magnet. The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing a first magnetic field along a plane perpendicular to the second direction and a second magnetic field along the plane, A change in the position of the magnetic field generator can be detected.

According to the position detection device as one embodiment of the present invention, high detection accuracy can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view showing an overall configuration example of an imaging device provided with a lens module including a position detection device according to an embodiment of the invention; FIG. 2 is an explanatory view schematically showing the inside of the imaging device shown in FIG. 1; FIG. 2 is an explanatory diagram schematically showing a main part of the position detection device shown in FIG. 1; FIG. 2 is an explanatory diagram schematically showing a main part of the driving device shown in FIG. 1; FIG. 2 is a side view showing a main part of the driving device shown in FIG. 1; FIG. 2 is a perspective view schematically showing a main part of the position detection device shown in FIG. 1; 2 is a circuit diagram showing a circuit configuration of a magnetic sensor in the position detection device shown in FIG. 1; FIG. FIG. 8 is a perspective view showing a part of one resistance part in FIG. 7; 2 is an enlarged plan view showing details of the positional relationship between a first magnetic field generator and a magnetic sensor in the position detection device shown in FIG. 1; FIG. FIG. 2 is an explanatory diagram showing a first magnetic field, a second magnetic field, and a magnetic field to be detected in the position detection device shown in FIG. 1; 2 is a characteristic diagram showing the relationship between the relative position of a lens with respect to a substrate and the angle to be detected in the position detection device shown in FIG. 1; FIG. FIG. 2 is a characteristic diagram showing the relationship between the position in the X-axis direction and the intensity of the first magnetic field in the position detection device shown in FIG. 1; 2 is a schematic diagram showing the distribution of the magnetic field in the XY plane in the lens module shown in FIG. 1; FIG. FIG. 4 is a characteristic diagram showing detection errors of a position detection device as a reference example; 2 is a characteristic diagram showing an experimental example of detection error in the position detection device shown in FIG. 1; FIG. FIG. 11 is a plan view showing an example of arrangement of magnets in a lens module as a first modified example of one embodiment of the present invention; 15 is an enlarged plan view showing the details of the positional relationship between the first magnetic field generator and the magnetic sensor in the position detection device shown in FIG. 14; FIG. 15 is a characteristic diagram showing the relationship between the position in the U-axis direction and the intensity of the first magnetic field in the position detection device shown in FIG. 14; FIG. FIG. 17 is an enlarged diagram showing the characteristic diagram shown in FIG. 16C further enlarged; FIG. 15 is an explanatory diagram for explaining the effects of the lens module as the first modified example shown in FIG. 14; FIG. 10 is a plan view showing the shape of magnets in a lens module as a second modified example of one embodiment of the present invention; FIG. 10 is a plan view showing the shape of a magnet as a third modified example of one embodiment of the present invention; FIG. 11 is a plan view showing the shape of a magnet as a fourth modified example of one embodiment of the present invention; FIG. 11 is a plan view showing the shape of a magnet as a fifth modified example of one embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. One Embodiment A first magnetic field generator that generates a first magnetic field for driving a lens, a second magnetic field generator that generates a second magnetic field and moves integrally with the lens, and the position of the lens An example of an imaging device with a lens module having a magnetic sensor for detection.
2. Modification

<1. one embodiment>
[Configuration of imaging device 100]
First, referring to FIGS. 1 and 2, the configuration of an imaging device 100 as an embodiment of the present invention will be described.

FIG. 1 is a perspective view showing an example of the overall configuration of an imaging device 100. As shown in FIG. FIG. 2 is an explanatory diagram schematically showing the inside of the imaging device 100. As shown in FIG. In FIG. 2, each component of the imaging device 100 is drawn with different dimensions and arrangement from the corresponding component shown in FIG. 1 for easy understanding.

The imaging device 100 constitutes, for example, a part of a smartphone camera that includes an optical image stabilization mechanism and an autofocus mechanism. The image pickup apparatus 100 includes an image sensor 200 as an image pickup device that acquires an image using, for example, CMOS, and a lens module 300 that guides light from a subject to the image sensor 200 .

[Configuration of lens module 300]
The lens module 300 has the position detection device 1, the drive device 3, the lens 5, the housing 6, and the substrate 7 according to one embodiment of the present invention. The position detection device 1 is a magnetic position detection device, and automatically focuses incident light so that light incident from a subject (hereinafter simply incident light) forms an image on the imaging surface of the image sensor 200. The position of the lens 5 is detected when performing. The driving device 3 is for moving the lens 5 in order to focus the incident light. The housing 6 accommodates the position detection device 1, the driving device 3, and the like, and protects them. The substrate 7 has an upper surface 7a. The upper surface 7a is a specific example corresponding to the "flat surface" of the present invention. Note that the substrate 7 is omitted in FIG. 1, and the housing 6 is omitted in FIG.

Here, as shown in FIGS. 1 and 2, the U-axis, V-axis and Z-axis are defined. The U-axis, V-axis and Z-axis are orthogonal to each other. In this embodiment, the Z-axis is perpendicular to the upper surface 7a of the substrate 7, and both the U-axis and the V-axis are parallel to the upper surface 7a of the substrate 7. FIG. Furthermore, in this embodiment, the +Z direction is the upward direction, and the −Z direction is the downward direction.
Also, the +Z direction and the −Z direction in the present embodiment, that is, the direction parallel to the Z axis, is a specific example corresponding to the “second direction” of the invention.

(lens 5)
The lens 5 is disposed above the upper surface 7a of the substrate 7 in such a posture that its optical axis direction coincides with the Z-axis. Further, the substrate 7 has an opening 7K that allows the light that has passed through the lens 5 to pass therethrough. As shown in FIG. 2, the lens module 300 is positioned with respect to the image sensor 200 so that the light from the subject sequentially passing through the lens 5 and the opening 7K of the substrate 7 is incident on the image sensor 200. It is

(Position detection device 1 and drive device 3)
Next, the position detecting device 1 and the driving device 3 according to this embodiment will be described in detail with reference to FIGS. 2 to 5. FIG. 3 is a perspective view showing the position detection device 1 and the driving device 3 of the lens module 300. FIG. FIG. 4 is a perspective view showing a plurality of coils 41-46 of the driving device 3. FIG. FIG. 5 is a side view showing a main part of the driving device 3. FIG.

The position detection device 1 has a first holding member 14 , a second holding member 15 , a plurality of first wires 16 and a plurality of second wires 17 . The second holding member 15 holds the lens 5 . The second holding member 15 has, for example, a tubular shape configured so that the lens 5 can be mounted therein. Note that the position detection device 1 does not have to have the first wire 16 and the second wire 17 .

The second holding member 15 is provided so as to be movable relative to the first holding member 14 along the optical axis direction of the lens 5, that is, along the Z-axis direction. In this embodiment, the first holding member 14 has a box-like shape configured to accommodate the lens 5 and the second holding member 15 therein. A plurality of second wires 17 connect the first holding member 14 and the second holding member 15 so that the second holding member 15 can move relative to the first holding member 14 in the Z-axis direction. , the second holding member 15 is supported.

The first holding member 14 is provided above the upper surface 7a of the substrate 7 so as to be movable with respect to the substrate 7 in both the U-axis direction and the V-axis direction. A plurality of first wires 16 connect the substrate 7 and the first holding member 14 while connecting the first wires 16 so that the first holding member 14 can move in the U-axis direction and the V-axis direction with respect to the substrate 7 . holding member 14. When the relative position of first holding member 14 with respect to substrate 7 changes, the relative position of second holding member 15 with respect to substrate 7 also changes.

The position detection device 1 further includes a first magnetic field generator 11 that generates a first magnetic field MF1, a second magnetic field generator 12 that generates a second magnetic field MF2, and a magnetic sensor 20. . The first magnetic field generator 11 includes a first magnet and a second magnet spaced apart at different positions. Specifically, the first magnetic field generating section 11 includes magnets 31A and 34A arranged along the upper surface 7a of the substrate 7 so as to sandwich the magnetic sensor 20 as the first magnet and the second magnet described above. have. Note that the magnets 31A and 34A are also elements that constitute the driving device 3 . The first magnetic field MF1 is a magnetic field obtained by synthesizing the magnetic fields generated by the magnets 31A and 34A. The magnet 31A and the magnet 34A are mainly composed of a first magnetic material and have, for example, a rectangular parallelepiped shape. Examples of the first magnetic material include neodymium magnet materials such as NdFeB. Magnet 31A and magnet 34A have a first temperature coefficient of residual magnetic flux density. Magnet 31A and magnet 34A are fixed to first holding member 14 . That is, the first magnetic field generator 11 is held by the first holding member 14 . The magnet 31A and the magnet 34A are driving magnets that generate driving force to move the second holding member 15 holding the lens 5 along the Z-axis. Further, magnet 31A and magnet 34A may be bias magnets for applying a bias to magnetic sensor 20. FIG.

As shown in FIG. 3, the magnet 31A has an end face 31A1 located at the +U direction end of the magnet 31A. The magnet 34A has an end surface 34A1 located at the end of the magnet 34A in the -V direction.

The second magnetic field generator 12 is provided so that its position relative to the first magnetic field generator 11 can be changed. The second magnetic field generator 12 has a magnet 13, for example. Therefore, the second magnetic field MF2 is the magnetic field generated by the magnet 13. FIG. The magnet 13 is mainly composed of a second magnetic material different from the first magnetic material, and has, for example, a cuboid shape like the magnets 31A and 34A. However, the shape of the magnet 13 is different from the shapes of the magnets 31A and 34A. Examples of the second magnetic material include neodymium magnet materials such as NdFeB. Alternatively, SmCo may be used as the second magnetic material. The magnet 13 preferably has a second temperature coefficient of residual magnetic flux density. Here, the absolute value of the temperature coefficient of the second residual magnetic flux density possessed by the magnet 13 is preferably smaller than the absolute value of the temperature coefficient of the first residual magnetic flux density possessed by the magnets 31A and 34A. The magnet 13 is a position detection magnet that generates a second magnetic field MF2 for detecting the position of the second holding member 15 that holds the lens 5 .

Magnet 13 is fixed to second holding member 15 so as to be positioned in a space near end face 31A1 (FIG. 3) of magnet 31A and end face 34A1 (FIG. 3) of magnet 34A. That is, the second magnetic field generator 12 is held by the second holding member 15 . When the relative position of the second holding member 15 with respect to the first holding member 14 changes along the Z-axis direction, the relative position of the second magnetic field generating section 12 with respect to the first magnetic field generating section 11 is also Z It is adapted to change along the axial direction.

The magnetic sensor 20 detects a detection target magnetic field MF at a predetermined detection position where it is arranged, and generates a detection signal corresponding to the direction of the detection target magnetic field MF. The magnetic sensor 20 is fixed to the substrate 7 so as to be positioned near both the end surface 31A1 of the magnet 31A and the end surface 34A1 of the magnet 34A. As will be described later, the distance from magnet 31A to magnetic sensor 20 and the distance from magnet 34A to magnetic sensor 20 are different from each other. The magnet 13 is arranged above the magnetic sensor 20, for example.

In this embodiment, the predetermined detection position is the position where the magnetic sensor 20 is arranged. As described above, when the position of the second magnetic field generator 12 relative to the position of the first magnetic field generator 11 changes, the distance between the predetermined detection position and the second magnetic field generator 12 changes. The magnetic field to be detected is the synthesized magnetic field MF of the first magnetic field MF1 and the second magnetic field MF2 at the detection position. The magnetic sensor 20 can detect a change in the position of the second magnetic field generator 12 by detecting the synthetic magnetic field MF. Note that the first magnetic field MF1 and the second magnetic field MF2 are shown in FIG. 6 described later. The resultant magnetic field MF is shown in FIG. 10A below. The positional relationship among the first magnetic field generator 11, the second magnetic field generator 12, and the magnetic sensor 20, and the configuration of the magnetic sensor 20 will be described in detail later.

The driving device 3 includes magnets 31A, 31B, 32A, 32B, 33A, 33B, 34A, and 34B and coils 41, 42, 43, 44, 45, and 46. As shown in FIGS. 1 and 2, the magnet 31A is positioned in the -V direction when viewed from the lens 5. FIG. The magnet 32A is positioned in the +V direction when viewed from the lens 5. As shown in FIG. The magnet 33A is positioned in the -U direction when viewed from the lens 5. FIG. The magnet 34A is positioned in the +U direction when viewed from the lens 5. As shown in FIG. That is, in the driving device 3, for example, magnets 31A, 32A, 33A, and 34A are arranged on the four sides of a square or rectangular area along the upper surface 7a of the substrate 7, respectively. Magnets 31B, 32B, 33B, and 34B are located above magnets 31A, 32A, 33A, and 34A (+Z direction), respectively. Magnets 31A, 31B, 32A, 32B, 33A, 33B, 34A, and 34B are held by first holding member 14 .

As shown in FIG. 3, the magnets 31A, 31B, 32A, and 32B each have a rectangular parallelepiped shape with the U-axis direction as the longitudinal direction. Magnets 33A, 33B, 34A, and 34B each have a rectangular parallelepiped shape with the V-axis direction as the longitudinal direction. The direction of magnetization of the magnets 31A and 32B is the +V direction. The direction of magnetization of the magnets 31B and 32A is the -V direction. The direction of magnetization of the magnets 33A and 34B is the +U direction. The direction of magnetization of the magnets 33B and 34A is the -U direction. In FIG. 5, the arrows drawn on the magnets 31A and 31B respectively represent the magnetization directions of the magnets 31A and 31B.

As shown in FIGS. 1 and 2, coil 41 is arranged between magnet 31A and substrate 7 . Coil 42 is arranged between magnet 32A and substrate 7 . Coil 43 is arranged between magnet 33A and substrate 7 . Coil 44 is arranged between magnet 34A and substrate 7 . Coil 45 is arranged between magnets 31A and 31B and lens 5 . A coil 46 is arranged between the magnets 32A, 32B and the lens 5 . Coils 41, 42, 43, and 44 are fixed to substrate 7, respectively. The coils 45 and 46 are fixed to the second holding member 15 respectively.

A magnetic field generated mainly by the magnet 31A is applied to the coil 41 . A magnetic field generated mainly by the magnet 32A is applied to the coil 42 . A magnetic field generated mainly by the magnet 33A is applied to the coil 43 . A magnetic field generated mainly by the magnet 34A is applied to the coil 44 .

2, 4 and 5, the coil 45 includes a first conductor portion 45A extending along the U-axis along which the magnet 31A extends, and a first conductor portion 45A extending along the U-axis along which the magnet 31B extends. and two third conductor portions 45C and 45D connecting the first conductor portion 45A and the second conductor portion 45B. 4, the coil 46 has a first conductor portion 46A extending along the U-axis along which the magnet 32A extends, and a second conductor portion 46A extending along the U-axis along which the magnet 32B extends. portion 46B and two third conductor portions 46C and 46D connecting the first conductor portion 46A and the second conductor portion 46B.

The +V direction component of the magnetic field generated by the magnet 31A is mainly applied to the first conductor portion 45A of the coil 45 . The -V direction component of the magnetic field generated by the magnet 31B is mainly applied to the second conductor portion 45B of the coil 45 . The −V direction component of the magnetic field generated by the magnet 32A is mainly applied to the first conductor portion 46A of the coil 46 . The +V direction component of the magnetic field generated by the magnet 32B is mainly applied to the second conductor portion 46B of the coil 46 .

The drive device 3 further comprises four magnetic sensors 30 fixed to the substrate 7 inside the coils 41-44, respectively. As will be described later, the four magnetic sensors 30 are used when changing the position of the lens 5 to reduce the effects of camera shake.

A magnetic sensor 30 located inside the coil 41 detects the magnetic field generated by the magnet 31A and generates a signal corresponding to the position of the magnet 31A. A magnetic sensor 30 located inside the coil 42 detects the magnetic field generated by the magnet 32A and generates a signal corresponding to the position of the magnet 32A. A magnetic sensor 30 located inside the coil 43 detects the magnetic field generated by the magnet 33A and generates a signal corresponding to the position of the magnet 33A. A magnetic sensor 30 located inside the coil 44 detects the magnetic field generated by the magnet 34A and generates a signal corresponding to the position of the magnet 34A. The magnetic sensor 30 can be composed of, for example, an element that detects a magnetic field, such as a Hall element. The driving device 3 may have only one of the magnetic sensor 30 positioned inside the coil 41 and the magnetic sensor 30 positioned inside the coil 42 . Similarly, the driving device 3 may have only one of the magnetic sensor 30 located inside the coil 43 or the magnetic sensor 30 located inside the coil 44 .

Next, the positional relationship among the first magnetic field generator 11, the second magnetic field generator 12 and the magnetic sensor 20 will be described in detail with reference to FIGS. 3 and 6. FIG. FIG. 6 is a perspective view showing the essential parts of the position detection device 1. As shown in FIG. Here, the +X direction and the +Y direction are defined as shown in FIG. Both the +X direction and the +Y direction are parallel to the upper surface 7a of the substrate 7 (see FIG. 2). The +X direction is a direction rotated 45° from the +U direction toward the +V direction. The +Y direction is a direction rotated 45° from the +V direction toward the -U direction. The direction opposite to the +X direction is the -X direction, and the direction opposite to the +Y direction is the -Y direction.
Note that the +X direction and the −X direction, that is, the direction parallel to the X axis are specific examples corresponding to the “first direction” of the present invention.

In FIG. 6, the arrow labeled MF1 represents the first magnetic field MF1 at the detection position. In this embodiment, the first magnetic field generator 11 and the magnetic sensor 20 are provided so that the direction of the first magnetic field MF1 at the detection position is the -Y direction. The direction of the first magnetic field MF1 at the detection position can be adjusted by, for example, the relative positions of the magnets 31A and 34A with respect to the magnetic sensor 20 and the attitudes of the magnets 31A and 34A with respect to the magnetic sensor 20. FIG. Magnets 31A and 34A are preferably arranged symmetrically with respect to the YZ plane including the detection position.

In FIG. 6, the arrow labeled MF2 represents the second magnetic field MF2 at the detection position, and the arrow drawn inside the magnet 13 represents the direction of magnetization of the magnet 13. As shown in FIG. Also, the direction of the second magnetic field MF2 is different from the direction of the first magnetic field MF1.

The direction of the magnetic field MF to be detected is different from both the direction of the first magnetic field MF1 and the direction of the second magnetic field MF2, and is the direction between them. The variable range of the direction of the magnetic field MF to be detected is less than 180°. In this embodiment, the direction of the second magnetic field MF2 is the -X direction orthogonal to the direction of the first magnetic field MF1. In this case, the variable range of the direction of the magnetic field MF to be detected is less than 90°.

Next, the configuration of the magnetic sensor 20 will be described with reference to FIG. FIG. 7 is a circuit diagram showing the configuration of the magnetic sensor 20. As shown in FIG. In the present embodiment, the magnetic sensor 20 is configured to generate a detection signal corresponding to the angle formed by the direction of the magnetic field MF to be detected with respect to the reference direction as the detection signal corresponding to the direction of the magnetic field MF to be detected. ing. In this embodiment, the reference direction is the +X direction.

As shown in FIG. 7, the magnetic sensor 20 has a Wheatstone bridge circuit 21 and a difference detector 22 . The Wheatstone bridge circuit 21 is connected in series with a power supply port V, a ground port G, two output ports E1 and E2, a first resistor R1 and a second resistor R2 connected in series. It includes a third resistance portion R3 and a fourth resistance portion R4. A first end of the first resistance portion R1 and a first end of the third resistance portion R3 are connected to the power supply port V, respectively. The second end of the first resistor R1 is connected to the first end of the second resistor R2 and the output port E1 respectively. A second end of the third resistor R3 is connected to a first end of the fourth resistor R4 and the output port E2, respectively. A second end of the second resistance portion R2 and a second end of the fourth resistance portion R4 are connected to the ground port G, respectively. A power supply voltage of a predetermined magnitude is applied to the power supply port V. FIG. Ground port G is connected to ground.

In the present embodiment, each of the first to fourth resistance units R1 to R4 includes a plurality of magnetoresistive elements (MR elements) connected in series. Each of the plurality of MR elements is, for example, a spin-valve MR element. This spin-valve MR element has a magnetization fixed layer whose magnetization direction is fixed, a free layer which is a magnetic layer whose magnetization direction changes according to the direction of the magnetic field to be detected, and a magnetic layer between the magnetization fixed layer and the free layer. and a non-magnetic layer disposed in the The spin-valve MR element may be a tunnel magnetoresistive element (TMR element) or a giant magnetoresistive element (GMR element). In a TMR element, the nonmagnetic layer is a tunnel barrier layer. In a GMR element, the nonmagnetic layer is a nonmagnetic conductive layer. In the spin-valve type MR element, the resistance value changes according to the angle formed by the magnetization direction of the free layer with respect to the magnetization direction of the magnetization fixed layer, and the resistance value becomes the minimum value when this angle is 0°. , the resistance becomes maximum when the angle is 180°. In FIG. 7, solid arrows represent the magnetization direction of the magnetization pinned layer in the MR element, and white arrows represent the magnetization direction of the free layer in the MR element.

The direction of magnetization of the magnetization fixed layers in the plurality of MR elements respectively included in the first resistance portion R1 and the fourth resistance portion R4 is the direction indicated by symbol MP1 in FIG. 6 (hereinafter referred to as direction MP1). On the other hand, the magnetization direction of the magnetization fixed layers in the plurality of MR elements included in the second resistance portion R2 and the third resistance portion R3 is the direction indicated by the sign MP2 opposite to the direction MP1 (hereinafter referred to as the direction MP2). ). In the present embodiment, each of the two directions orthogonal to the direction MP1 is different from both the direction of the first magnetic field MF1 and the direction of the second magnetic field MF2 in the reference plane. In the reference plane, the two directions perpendicular to the direction MP2 are the same as the two directions perpendicular to the direction MP1. Therefore, in the reference plane, each of the two directions perpendicular to the direction MP2 is also different from both the direction of the first magnetic field MF1 and the direction of the second magnetic field MF2. The potential of the output port E1, the potential of the output port E2, and the potential difference between the output ports E1 and E2 change according to the cosine of the angle formed by the direction of the magnetic field MF to be detected with respect to the direction MP1. The difference detector 22 outputs a signal corresponding to the potential difference between the output ports E1 and E2 as a detection signal. The detection signal depends on the potential of the output port E1, the potential of the output port E2, and the potential difference between the output ports E1 and E2. Further, since the detection signal changes according to the direction of the magnetic field MF to be detected, it is a signal corresponding to the direction of the magnetic field MF to be detected.

Note that the magnetization directions of the magnetization fixed layers in the plurality of MR elements may be slightly deviated from the above-described directions from the viewpoint of manufacturing accuracy of the MR elements.

Here, an example of the configuration of the first to fourth resistance sections R1 to R4 will be described with reference to FIG. FIG. 8 is a perspective view showing a part of one resistance part in the magnetic sensor 20 shown in FIG. In this example, one resistor section has a plurality of lower electrodes 162 , a plurality of magnetoresistive (MR) elements 150 and a plurality of upper electrodes 163 . A plurality of lower electrodes 162 are arranged on a substrate (not shown). Each lower electrode 162 has an elongated shape. A gap is formed between two lower electrodes 162 that are adjacent in the longitudinal direction of the lower electrodes 162 . As shown in FIG. 8, the MR elements 150 are arranged on the upper surface of the lower electrode 162 near both ends in the longitudinal direction. The MR element 150 includes, for example, a magnetization free layer 151, a nonmagnetic layer 152, a magnetization fixed layer 153, and an antiferromagnetic layer 154 which are stacked in order from the lower electrode 162 side. The magnetization free layer 151 is electrically connected to the lower electrode 162 . The antiferromagnetic layer 154 contains an antiferromagnetic material and causes exchange coupling with the magnetization fixed layer 153 to fix the magnetization direction of the magnetization fixed layer 153 . A plurality of upper electrodes 163 are arranged on the plurality of MR elements 150 . Each upper electrode 163 has an elongated shape and is arranged on two lower electrodes 162 adjacent in the longitudinal direction of the lower electrode 162 to electrically connect the antiferromagnetic layers 154 of two adjacent MR elements 150 . do. With such a configuration, the resistor portion shown in FIG. 8 has a plurality of MR elements 150 connected in series by a plurality of lower electrodes 162 and a plurality of upper electrodes 163 . The arrangement of the magnetization free layer 151, the nonmagnetic layer 152, the magnetization fixed layer 153 and the antiferromagnetic layer 154 in the MR element 150 may be upside down from the arrangement shown in FIG.

Next, with reference to FIG. 9, the details of the positional relationship between the magnets 31A and 34A in the first magnetic field generator 11 and the magnetic sensor 20 will be described. FIG. 9 is a plan view schematically showing the positional relationship between the magnets 31A and 34A and the magnetic sensor 20 along the upper surface 7a orthogonal to the Z-axis.

As shown in FIG. 9, in the X-axis direction, the center position P20 of the magnetic sensor 20 is located at a position other than the intermediate position P11 between the magnets 31A and 34A in the region GP between the magnets 31A and 34A. be. The intermediate position P11 refers to a position on a line equidistant from each of a vertex 31AP and a vertex 34AP, which will be described later. In particular, it is preferable that all parts of the magnetic sensor 20 are provided at positions other than the intermediate position P11 in the region GP in the X-axis direction.

The magnet 13 of the second magnetic field generator 12 is arranged at an intermediate position P11 between the magnets 31A and 34A in the X-axis direction. Here, the magnet 13 is arranged at an intermediate position P11 between the magnets 31A and 34A in the X-axis direction, so that a part of the magnet 13 exists at the intermediate position P11 in the X-axis direction. , means that the magnet 13 is located in the region GP. In particular, it is preferable that the center position P13 in the X-axis direction of the magnet 13 of the second magnetic field generator 12 is located at the intermediate position P11 in the X-axis direction.

The magnet 31A also includes an apex 31AP where an end face 31A1 along the V-axis direction and a side face 31A2 forming an angle of 90±5° with respect to the end face 31A1 intersect. The magnet 34A includes an apex 34AP where an end face 34A1 along the U-axis direction and a side face 34A2 forming an angle of 90±5° with respect to the end face 34A1 intersect. Therefore, the end faces 31A1 and 34A1 form an angle of 90±5° with each other, and the side faces 31A2 and 34A2 form an angle of 90±5° with each other. Both the end faces 31A1, 34A1 and the side faces 31A2, 34A2 are substantially perpendicular to the upper face 7a. The magnets 31A and 34A are arranged in a posture that minimizes the distance from the magnetic sensor 20 at each of the vertices 31AP and 34AP.
Here, the end surfaces 31A1 and 34A1 are specific examples corresponding to the "first surface" of the present invention, and the side surfaces 31A2 and 34A2 are specific examples corresponding to the "second surface" of the present invention. .

Furthermore, the position detection device 1 preferably satisfies the following conditional expression (1).
0<D<(G×2/5) ……(1)
However, D is the distance from the intermediate position P11 between the vertex 31AP of the magnet 31A and the vertex 34AP of the magnet 34A to the center position P20 of the magnetic sensor 20 in the X-axis direction. G is the distance between the vertex 31AP of the magnet 31A and the vertex 34AP of the magnet 34A in the X-axis direction.

Furthermore, the position detection device 1 preferably satisfies the following conditional expression (2).
(G/6)<D<(G/3) ……(2)

Next, the operation of the driving device 3 will be described with reference to FIGS. 1 to 5. FIG. First, the optical image stabilization mechanism and the autofocus mechanism will be briefly described. The driving device 3 constitutes a part of an optical camera shake correction mechanism and an autofocus mechanism. The driving device 3, the optical image stabilization mechanism, and the autofocus mechanism are controlled by a control section 4 (see FIG. 1) provided outside the imaging device 100. FIG.

The optical camera shake correction mechanism is configured to detect camera shake using, for example, a gyro sensor or the like outside the imaging device 100 . When the optical image stabilization mechanism detects camera shake, the controller 4 controls the driving device 3 so that the position of the lens 5 relative to the substrate 7 changes according to the mode of camera shake. As a result, the absolute position of the lens 5 can be stabilized, and the effects of camera shake can be reduced. The relative position of the lens 5 with respect to the substrate 7 changes in the direction parallel to the U-axis or in the direction parallel to the V-axis depending on the mode of camera shake.

The autofocus mechanism is configured such that the image sensor 200, the autofocus sensor, or the like can detect a state in which the object is in focus. The control unit 4 changes the position of the lens 5 relative to the substrate 7 along the Z-axis by the driving device 3 so that the object is in focus. As a result, the subject can be automatically focused.

Next, the operation of the driving device 3 related to the optical image stabilization mechanism will be described. When a current is applied to the coils 41 and 42 by the control unit 4, the interaction between the magnetic field generated by the magnets 31A and 32A and the magnetic field generated by the coils 41 and 42 causes the first holding mechanism in which the magnets 31A and 32A are fixed. Member 14 moves along the V-axis. As a result, the lens 5 also moves along the V-axis. Further, when current is supplied to the coils 43 and 44 by the control unit 4, the interaction between the magnetic field generated by the magnets 33A and 34A and the magnetic field generated by the coils 43 and 44 causes the magnets 33A and 34A to be fixed to the first first magnetic field. holding member 14 moves along the U-axis. As a result, the lens 5 also moves along the U axis. The control unit 4 detects the position of the lens 5 by measuring signals generated by the magnetic sensor 30 and corresponding to the positions of the magnets 31A, 32A, 33A, and 34A.

Next, the operation of the driving device 3 related to the autofocus mechanism will be described. When moving the relative position of the lens 5 with respect to the substrate 7 along the Z-axis, the control unit 4 causes the current in the +U direction to flow in the first conductor 45A and the current in the -U direction to flow in the second conductor 45B. A current is passed through the coil 45 so that the current flows. The control unit 4 further causes current to flow in the coil 46 in the -U direction through the first conductor portion 46A and in the +U direction through the second conductor portion 46B. These currents and the magnetic fields generated by the magnets 31A, 31B, 32A, and 32B cause the first conductor portion 45A and the second conductor portion 45B of the coil 45 and the first conductor portion 46A and the second conductor portion of the coil 46 A Lorentz force in the +Z direction acts on 46B. As a result, the second holding member 15 to which the coils 45 and 46 are fixed moves in the +Z direction. As a result, the lens 5 also moves in the +Z direction.

When moving the relative position of the lens 5 with respect to the substrate 7 in the -Z direction, the control unit 4 causes the coils 45 and 46 to flow currents in the opposite directions to those when moving in the +Z direction.

[Action and effect of imaging device 100]
Next, the operation and effects of the position detection device 1 according to the present embodiment and the imaging device 100 including the same will be described. The position detection device 1 according to this embodiment is used to detect the position of the lens 5 . In this embodiment, when the relative position of lens 5 with respect to substrate 7 changes, the relative position of second holding member 15 with respect to substrate 7 and first holding member 14 also changes. As described above, the first holding member 14 holds the first magnetic field generating section 11 and the second holding member 15 holds the second magnetic field generating section 12 . Therefore, when the relative position of the lens 5 changes as described above, the relative position of the second magnetic field generator 12 with respect to the first magnetic field generator 11 changes. In this embodiment, the direction of change in the relative position of the second magnetic field generator 12 with respect to the first magnetic field generator 11 is the optical axis direction of the lens 5, that is, the direction parallel to the Z-axis.

When the relative position of the second magnetic field generator 12 with respect to the first magnetic field generator 11 changes, the relative position of the first magnetic field generator 11 with respect to the substrate 7 does not change, but the second magnetic field generator with respect to the substrate 7 does not change. The relative position of portion 12 varies. Therefore, when the relative position of the second magnetic field generator 12 with respect to the first magnetic field generator 11 changes, the intensity and direction of the first magnetic field MF1 and the direction of the second magnetic field MF2 do not change, but the second magnetic field The intensity of MF2 varies. When the strength of the second magnetic field MF2 changes, the direction and strength of the magnetic field MF to be detected also change, and accordingly the value of the detection signal generated by the magnetic sensor 20 also changes. The value of the detection signal generated by the magnetic sensor 20 changes depending on the relative position of the second magnetic field generator 12 with respect to the substrate 7 . The controller 4 detects the relative position of the second magnetic field generator 12 with respect to the substrate 7 by measuring the detection signal from the magnetic sensor 20 . The relative position of the second magnetic field generator 12 with respect to the substrate 7 represents the relative position of the lens 5 with respect to the substrate 7 .

The direction MP1 and the direction MP2 and the first magnetic field MF1 and the second magnetic field MF2 will now be described in detail with reference to FIG. 10A. In FIG. 10A, symbol RP represents a reference plane, and symbol P represents a detection position. In FIG. 10A, the arrow labeled MF1 represents the first magnetic field MF1, the arrow labeled MF2 represents the second magnetic field MF2, and the arrow labeled MF represents the magnetic field to be detected. In FIG. 10A, the X-direction axis indicates the X-direction magnetic field strength Hx, and the Y-direction axis indicates the Y-direction magnetic field strength Hy.

Since the detection target magnetic field MF is a composite magnetic field of the first magnetic field MF1 and the second magnetic field MF2, the direction of the detection target magnetic field MF is the direction of the first magnetic field MF1 and the direction of the second magnetic field MF2. Unlike any other, it is in the direction between the direction of the first magnetic field MF1 and the direction of the second magnetic field MF2. In FIG. 10A, two directions perpendicular to the direction MP1 within the reference plane RP are denoted by PP1 and PP2. Two directions orthogonal to the direction MP2 in the reference plane RP are the same as the direction PP1 and the direction PP2. As described above, in the present embodiment, each of direction PP1 and direction PP2 is different from both the direction of first magnetic field MF1 and the direction of second magnetic field MF2.

When viewed counterclockwise from the reference direction (+X direction) in FIG. 10A, the angle formed by the direction of the detection target magnetic field MF with respect to the reference direction (+X direction) is called a detection target angle, and is represented by the symbol θ. The detection target angle θ represents the direction of the detection target magnetic field MF. In this embodiment, the magnetic sensor 20 generates a detection signal corresponding to the detection target angle θ.

Here, with reference to FIG. 10B, the relationship between the relative position of the lens 5 with respect to the substrate 7 and the detection target angle θ in this embodiment will be described. FIG. 10B is a characteristic diagram showing the relationship between the relative position of the lens 5 with respect to the substrate 7 and the detection target angle θ. In FIG. 10B, the horizontal axis indicates the relative position of the lens 5 with respect to the substrate 7, and the vertical axis indicates the target angle θ.

In this embodiment, the distance between the detection position P and the second magnetic field generation section 12 when the second magnetic field generation section 12 is closest to the detection position P is defined as the shortest distance, and the lens 5 with respect to the substrate 7 is expressed by a value obtained by subtracting the shortest distance from the distance between the second magnetic field generator 12 at an arbitrary position and the detection position P. Here, the movable range of the relative position of the lens 5 with respect to the substrate 7 is set to a range of 0 to 0.3 mm as an example.

In this embodiment, as shown in FIG. 10B, when the relative position of the lens 5 with respect to the substrate 7 changes within a movable range of 0 to 0.3 mm, the detection target angle θ is within a variable range of 207° to 240°. Change. A change in the detection target angle θ is linear with respect to a change in the relative position of the lens 5 with respect to the substrate 7 . The detection target angle θ represents the direction of the detection target magnetic field MF. Therefore, the variable range of the detection target angle θ corresponds to the variable range of the direction of the detection target magnetic field MF corresponding to the movable range of the relative position of the lens 5 with respect to the substrate 7 . In FIG. 10A, the range indicated by symbol θR represents the variable range of the detection target angle θ.

As shown in FIG. 10A, in the present embodiment, the directions PP1 and PP2 orthogonal to the magnetization direction of the magnetization fixed layer are respectively aligned with the direction of the first magnetic field MF1 and the direction of the second magnetic field within the reference plane RP. Different from any of the directions of MF2. As a result, the position detection device 1 according to the present embodiment can perform highly accurate position detection.

Further, in the present embodiment, in the X-axis direction, the center position P20 of the magnetic sensor 20 is set to a position other than the intermediate position P11 in the region GP between the magnets 31A and 34A. Therefore, for example, the relative position (mounted relative position) between the actually mounted magnetic sensor 20 and the magnets 31A and 34A is the designed relative position (designed relative position) between the magnetic sensor 20 and the magnets 31A and 34A. Even if there is a deviation, the error in the output signal of the magnetic sensor 20 can be reduced. Hereinafter, the influence of the relative positions of magnetic sensor 20 and magnets 31A and 34A on first magnetic field MF1 applied to magnetic sensor 20 will be described with reference to FIG.

FIG. 11 is a characteristic diagram showing the position dependence of the strength of the first magnetic field MF1 in the position detection device 1 as an experimental example of one embodiment of the present invention. (A) at the top of FIG. 11 is a characteristic diagram showing the relationship between the position [μm] in the X-axis direction in the region GP and the strength of the first magnetic field MF1 in the region GP. In FIG. 11A, of the first magnetic field MF1 generated by the magnets 31A and 34A, the X-axis direction component magnetic field Hx is indicated by a broken line, and the Y-axis direction component magnetic field Hy is indicated by a solid line. there is (B) in the middle of FIG. 11 is the angle between the direction of the magnetic field Hx, which is the X-axis component of the first magnetic field MF1, and the direction of the magnetic field Hy, which is the Y-axis component of the first magnetic field MF1. 4 is a characteristic diagram showing how θ [deg] changes according to the position [μm] in the X-axis direction in the region GP. FIG. (C) at the bottom of FIG. 11 shows how the gradient [deg/μm] of the angle θ shown in FIG. It is a characteristic diagram showing whether to do. As shown in FIG. 11A, the magnetic field Hx, which is the component in the X-axis direction, and the magnetic field Hy, which is the component in the Y-axis direction, of the first magnetic field MF1 fluctuate according to the position in the X-axis direction. That is, as shown in FIG. 11B, the direction (angle) of the first magnetic field MF1 applied to the magnetic sensor 20 varies according to the position of the magnetic sensor 20 in the X-axis direction. As shown in FIG. 11C, the gradient of the variation becomes smaller in the vicinity of the intermediate position P11 than in the X-axis direction. Therefore, by setting the center position P20 of the magnetic sensor 20 to a position other than the intermediate position P11, even if the mounting relative position of the magnetic sensor 20 deviates from the design relative position, the error in the output signal of the magnetic sensor 20 can be reduced. can be reduced.

Specifically, for example, by satisfying the conditional expression (1) described above, the measurement error of the magnetic sensor 20 due to the positional deviation of the magnetic sensor 20 is greater than when the center position P20 of the magnetic sensor 20 is arranged at the intermediate position P11. can be reduced. In particular, by satisfying conditional expression (2) above, the measurement error of the magnetic sensor 20 can be further reduced.

FIG. 12 is a schematic diagram showing an example of distribution of the first magnetic field MF1 in the XY plane in the lens module 300. As shown in FIG. As shown in FIG. 12, the magnets 31A-34A are magnetized in a direction orthogonal to their respective longitudinal directions. Also, the magnetic flux passing through the magnetic sensor 20 is directed approximately in the Y-axis direction.

In addition, in the present embodiment, the second magnetic field generating section 12 is arranged at an intermediate position P11 between the magnets 31A and 34A in the X-axis direction. Therefore, it is easy to balance the weight of the position detecting device 1 as a whole, so that the lens 5 can easily maintain a desired posture when the second magnetic field generating section 12 moves in the Z-axis direction. Specifically, for example, the tilt of the optical axis of the lens 5 with respect to the image sensor 200 can be kept small. In particular, if the center position P13 in the X-axis direction of the magnet 13 is aligned with the intermediate position P11, it is easier to maintain the weight balance. It is easy to maintain the posture of 5 more accurately.

Moreover, in the present embodiment, the shape of the magnets 31A and 34A and the shape of the magnet 13 are made different. Therefore, the magnets 31A and 34A in the first magnetic field generating section 11 have a shape suitable as a driving source for moving the lens 5 along the Z-axis, while the magnet 13 in the second magnetic field generating section 12 is a magnet. It can have a shape suitable for the magnetic sensor 20 to detect the position along the Z-axis of 13 . Moreover, in the present embodiment, the first magnetic material that is the main component of the magnets 31A and 34A in the first magnetic field generating section 11 and the second magnetic material that is the main component of the magnet 13 in the second magnetic field generating section 12 are used. made different from the material. Therefore, even if the shape of the magnets 31A and 34A in the first magnetic field generating section 11 and the shape of the magnet 13 in the second magnetic field generating section 12 are different, the thermal demagnetization rate of the magnets 31A and 34A and the heat of the magnet 13 are different. demagnetization rate can be approximated. Therefore, in the imaging device 100, even when the temperature of the environment in which the position detection device 1 is installed changes, the relative position of the second magnetic field generation section 12 with respect to the first magnetic field generation section 11 and the magnetic sensor 20 remains unchanged. change is less likely to occur. That is, the accuracy of position detection of the lens 5 by the magnetic sensor 20 is less affected by changes in the environmental temperature, and the temperature dependency of the position detection accuracy of the lens 5 by the magnetic sensor 20 can be reduced. As a result, according to the imaging apparatus 100 of the present embodiment, the position of the lens 5 can be changed more accurately, and a better image can be obtained.

Further, in the present embodiment, the absolute value of the temperature coefficient of the second residual magnetic flux density possessed by the magnet 13 is made smaller than the absolute value of the temperature coefficient of the first residual magnetic flux density possessed by the magnets 31A and 34A. Therefore, the position detection deviation of the lens 5 by the magnetic sensor 20 due to changes in the environmental temperature can be further reduced.

Here, FIG. 13A shows temperature characteristics in a position detection device as a reference example. In FIG. 13A, the horizontal axis represents the actual displacement [μm] of the lens 5 along the Z axis, and the vertical axis represents the displacement of the lens 5 along the Z axis when the environmental temperature varied from 25° C. to 65° C. It represents the maximum error [μm] of the measured value by the position detection device with respect to the actual amount of displacement. The amount of displacement [μm] on the horizontal axis is 0 at the reference position, the displacement in the +Z direction is represented by a positive value, and the displacement in the −Z direction is represented by a negative value. In this reference example, NdFeB is used as the constituent material of the magnets 31A and 34A and the constituent material of the magnet 13. FIG. In this reference example, each of the magnets 31A and 34A has a rectangular parallelepiped shape of length 7 mm×width 1 mm×thickness 0.5 mm, and magnet 13 has a shape of length 1 mm×width 0.8 mm×thickness 0.8 mm. It is a 5 mm rectangular parallelepiped. As a result, while the magnets 31A and 34A have a thermal demagnetization rate of -3.5%, the magnet 13 has a thermal demagnetization rate of -4.51%. As shown in FIG. 13A, in the position detection device as the reference example, when the lens 5 is displaced in the range from -400 μm to +400 μm along the Z axis, an error of up to 6 μm occurs.

FIG. 13B shows an experimental example of temperature characteristics in the position detection device 1 of this embodiment. In FIG. 13B, the horizontal axis represents the actual amount of displacement [μm] of the lens 5 along the Z axis, and the vertical axis represents the displacement of the lens 5 along the Z axis when the environmental temperature varied from 25° C. to 65° C. It represents the maximum error [μm] of the measured value by the position detection device with respect to the actual amount of displacement. As in FIG. 13A, the displacement amount [μm] on the horizontal axis is 0 at the reference position, the displacement in the +Z direction is represented by a positive value, and the displacement amount in the −Z direction is represented by a negative value. It is In this experimental example, NdFeB is used as the constituent material of the magnets 31A and 34A, and SmCo is used as the constituent material of the magnet 13. FIG. In this experimental example, each of the magnets 31A and 34A has a rectangular parallelepiped shape of length 7 mm×width 1 mm×thickness 0.5 mm, and magnet 13 has a shape of length 1 mm×width 0.8 mm×thickness 0.8 mm. It is a 5 mm rectangular parallelepiped. As a result, the thermal demagnetization rate of the magnets 31A and 34A is -3.5%, and the thermal demagnetization rate of the magnet 13 is -3.5%. As shown in FIG. 13B, in this experimental example, when the lens 5 is displaced in the range of −400 μm to +400 μm along the Z axis, the error can be suppressed to a maximum of 0.6 μm. Recognize.

<2. Variation>
Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above-described embodiment, a full-bridge circuit is formed using four resistors as the sensor section, but in the present invention, for example, two resistors are used to form a half-bridge circuit. good too. Also, the shapes and dimensions of the plurality of magnetoresistive elements may be the same or different. Also, the resistance section may include, for example, a magnetic sensing element. Here, the magnetic detection element refers to any element having a function of detecting a magnetic field, and is not limited to a spin valve type MR element, an anisotropic magnetoresistive effect element (AMR element), a Hall element, etc. (for example, a planar It is a concept that includes Hall elements and vertical Hall elements). In general, a planar Hall element tends to have a sensitivity axis perpendicular to the substrate, and a magnetoresistive effect element and a vertical Hall element tend to have a sensitivity axis parallel to the substrate. Alternatively, it is preferable to use a magnetic sensing element having a sensitivity axis parallel to a plane perpendicular to the Z axis. Also, the dimensions of each component, the layout of each component, etc. are examples, and are not limited to these.

Further, the position detection device of the present invention is not limited to a device for detecting the position of a lens, and may be a device for detecting the spatial position of an object other than a lens.

Further, in the above embodiment, the first magnet is used as a drive source for driving the lens and the second holding member that holds the lens, and the first magnetic field is generated. is not limited to In the present invention, for example, the first magnet may be used as a bias magnet that applies a bias to the magnetoresistive element of the magnetic sensor.

Further, in the position detecting device 1 of the above-described embodiment, the first magnetic material as the main component of the first magnet and the second magnetic material as the main component of the second magnet are different from each other. By making the shape of the first magnet and the shape of the second magnet different, the thermal demagnetization rate of the first magnet and the thermal demagnetization rate of the second magnet are brought close to each other. However, the invention is not limited to this. For example, while the main component of the first magnet and the main component of the second magnet are both the same magnetic material (for example, the first magnetic material), the permeance coefficient of the first magnet (for convenience, the first permeance coefficient) ) and the permeance coefficient of the second magnet (referred to as the second permeance coefficient for convenience) may be substantially the same. In that case, for example, the shape of the first magnet and the shape of the second magnet should be the same or similar to each other. Even in that case, the thermal demagnetization rate of the first magnet and the thermal demagnetization rate of the second magnet can be brought close to each other. For this reason, the temperature characteristics of the first magnet and the temperature characteristics of the second magnet are approximated, and errors in position detection accuracy can be reduced.

In the above embodiment, the magnets 31A, 32A, 33A, and 34A are arranged on the four sides of the square or rectangular area along the upper surface 7a of the substrate 7, but the present invention is limited to this. not a thing For example, like a lens module 300A as a modification shown in FIG. may In the lens module 300A, the direction along the U-axis corresponds to the "first direction" of the invention. In the lens module 300A, the lens 5 is arranged in the central area surrounded by the magnets 31A, 32A, 33A, 34A, and the magnets 31A, 32A, 33A, 34A and the lens 5 are arranged so as to surround the lens 5. A coil C is arranged in the gap. The magnets 31A, 32A, 33A, and 34A face the outer surface of the coil C, respectively, and extend in a direction orthogonal to the extending direction of the coil C (the direction of the arrow shown in FIG. 14, or the direction opposite to the direction of the arrow). direction). The lens 5 and the coil C are integrally held by a holding member and sandwiched between a pair of leaf springs in the Z-axis direction. The lens 5 and the coil C held by the holding member are movable in the Z-axis direction by elastic deformation of the pair of plate springs. In lens module 300A, a first magnetic field across coil C along the UV plane is formed by magnets 31A, 32A, 33A, 34A. When a drive current is supplied to the coil C, an induced magnetic field is generated around the coil C, and the lens 5 and the coil C are displaced along the Z-axis direction.

Next, the details of the positional relationship between the magnets 31A and 34A and the magnetic sensor 20 in the lens module 300A will be described with reference to FIG. FIG. 15 is a plan view schematically showing the positional relationship between the magnets 31A and 34A and the magnetic sensor 20 along the upper surface 7a orthogonal to the Z-axis in the lens module 300A.

As shown in FIG. 15, in the U-axis direction, the center position P20 of the magnetic sensor 20 is located at a position other than the intermediate position P11 between the magnets 31A and 34A in the region GP between the magnets 31A and 34A. be. In particular, all portions of the magnetic sensor 20 may be provided at positions other than the intermediate position P11 in the region GP in the U-axis direction. Also, in the lens module 300A, the center position P20 of the magnetic sensor 20 in the U-axis direction should be closer to the intermediate position P11 than both the magnets 31A and 34A. That is, the center position P20 is located between the intermediate position P31 between the intermediate position P11 and a later-described vertex 31AP and the intermediate position P11, or between the intermediate position P34 between the intermediate position P11 and a later-described vertex 34AP and the intermediate position P11. It should be located between

The magnet 31A also includes an apex 31AP where an end face 31S1 along the U-axis direction and a side face 31S2 forming an angle of 45±5° with respect to the end face 31S1 intersect. The magnet 34A includes an apex 34AP where an end face 34S1 along the U-axis direction and a side face 34S2 forming an angle of 45±5° with respect to the end face 34S1 intersect. Therefore, the end faces 31S1 and 34S1 are substantially parallel to each other, and the side faces 31S2 and 34S2 form an angle of 90±5° with each other. Both the end surfaces 31S1, 34S1 and the side surfaces 31S2, 34S2 are substantially perpendicular to the upper surface 7a. The magnets 31A and 34A are arranged in a posture that minimizes the distance from the magnetic sensor 20 at each of the vertices 31AP and 34AP.

In the lens module 300A as this modified example, the central position P20 of the magnetic sensor 20 is set to a position other than the intermediate position P11 in the region GP between the magnets 31A and 34A in the U-axis direction. Therefore, for example, the relative position (mounted relative position) between the actually mounted magnetic sensor 20 and the magnets 31A and 34A is the designed relative position (designed relative position) between the magnetic sensor 20 and the magnets 31A and 34A. Even if there is a deviation, the error in the output signal of the magnetic sensor 20 can be reduced. Hereinafter, the influence of the relative positions of magnetic sensor 20 and magnets 31A and 34A on first magnetic field MF1 applied to magnetic sensor 20 will be described with reference to FIG.

FIG. 16 is a characteristic diagram showing the position dependence of the intensity of the first magnetic field MF1 in the position detection device 1A. (A) at the top of FIG. 16 is a characteristic diagram showing the relationship between the position [μm] in the U-axis direction in the region GP and the strength of the first magnetic field MF1 in the region GP. In FIG. 16A, of the first magnetic field MF1 generated by the magnets 31A and 34A, the magnetic field Hu of the U-axis direction component is indicated by a broken line, and the magnetic field Hv of the V-axis direction component is indicated by a solid line. there is (B) in the middle of FIG. 16 is the angle between the direction of the magnetic field Hu, which is the U-axis direction component of the first magnetic field MF1, and the direction of the magnetic field Hv, which is the V-axis direction component of the first magnetic field MF1. FIG. 4 is a characteristic diagram showing how θ [deg] changes according to the position [μm] in the U-axis direction in the region GP. (C) at the bottom of FIG. 16 shows how the gradient [deg/μm] of the angle θ shown in FIG. It is a characteristic diagram showing whether to do. As shown in FIG. 16A, the magnetic field Hu that is the U-axis direction component and the magnetic field Hv that is the V-axis direction component of the first magnetic field MF1 fluctuate according to the position in the U-axis direction. That is, as shown in FIG. 16B, the direction (angle) of the first magnetic field MF1 applied to the magnetic sensor 20 varies according to the position of the magnetic sensor 20 in the U-axis direction. As shown in FIG. 16C, the gradient of the variation becomes smaller in the vicinity of the intermediate position P11 than in the U-axis direction. Therefore, by setting the center position P20 of the magnetic sensor 20 to a position other than the intermediate position P11, even if the mounting relative position of the magnetic sensor 20 deviates from the design relative position, the error in the output signal of the magnetic sensor 20 can be reduced. can be reduced.

Specifically, the position detection device 1A in the lens module 300A preferably satisfies the following conditional expression (3), for example. This is because the measurement error of the magnetic sensor 20 due to the positional deviation of the magnetic sensor 20 can be reduced more than when the center position P20 of the magnetic sensor 20 is arranged at the intermediate position P11 (see (C) of FIG. 16).
0<D<(G/4) ……(3)
However, D is the distance from the intermediate position P11 between the vertex 31AP of the magnet 31A and the vertex 34AP of the magnet 34A to the center position P20 of the magnetic sensor 20 in the U-axis direction. G is the distance between the vertex 31AP of the magnet 31A and the vertex 34AP of the magnet 34A in the U-axis direction.

In particular, the position detection device 1A preferably satisfies the following conditional expression (4) as shown in FIG. This is because the measurement error of the magnetic sensor 20 can be further reduced. FIG. 17 is an enlarged view of part of FIG. 16(C).
(G/12)<D<(G/5) ……(4)

Further, in the lens module 300A, as shown in FIG. 18(A), the center position P20 of the magnetic sensor 20 is shifted from the intermediate position P11 between the magnets 31A and 34A. As compared with the case where the center position P20 of the magnetic sensor 20 is provided at the intermediate position P11, the space around the lens 5 having a circular planar shape can be effectively used. As a result, when mounting a lens 5 having a predetermined size, the area occupied by the entire lens module 300A can be reduced. Therefore, it is suitable for miniaturization of the lens module 300A and miniaturization of the imaging device 100 including the lens module 300A. FIG. 18 is an explanatory diagram for explaining the effect of the lens module 300A as this modified example. Also, in the lens module 300A, the shapes and arrangement positions of the magnets 31A, 32A, 33A, and 34A have been described. , 32A, 33A, and 34A.

In the above modification, as shown in FIGS. 14 and 15, for example, the planar shape of the four magnets has an outline of an isosceles right triangle with a base angle of 45°, but the present invention is limited to this. not to be The present invention is characterized in that the first magnet and the second magnet respectively form an angle of 90±5° with respect to the plane and the first surface along the first direction and the a second face that is angled and includes a portion that forms an angle of 45±5° or less with respect to the first face, the second face on the first magnet and the second face on the second magnet; are provided so as to face each other in the first direction, and the farther away from the first surface of the first magnet and the first surface of the second magnet, the farther away from each other in the first direction. . For example, like the magnets 31A and 34A shown in FIG. 19A, end faces 31S1 and 34S1 along the U-axis direction and side faces 31S2 and 34S2 forming an angle θ of 45±5° or less with respect to the end faces 31S1 and 34S1. The planar shape may have a contour of a right-angled triangle. Moreover, for example, like the magnets 31A and 34A shown in FIG. 19B, the planar shape may have a polygonal (hexagonal in FIG. 19B) outline. Moreover, the planar shape may have a contour including straight lines and curved lines, for example, like the magnets 31A and 34A shown in FIG. 19C. Furthermore, for example, magnets 31A and 34A shown in FIG. 19D may have curved side surfaces 31S2 and 34S2.

Further, the first surface of the present invention is not the actual outer surface (first surface) of the magnet itself, but a geometric first imaginary surface partially including the first surface. The surface 2 may be a geometric second imaginary surface partially including the second surface instead of the actual outer surface (second surface) of the magnet itself.

Further, in the above embodiment, as shown in FIG. 9, for example, all parts of the magnetic sensor 20 are arranged to fit within the region GP between the magnets 31A and 34A in the X-axis direction. The invention is not limited to this. A portion of the magnetic sensor may protrude from the region between the first magnet and the second magnet in the first direction.

In addition to the concept of being geometrically strictly 90°, the concept of orthogonality includes an error of about ±5° from 90° due to manufacturing error.

According to the position detection device as one embodiment of the present invention, high detection accuracy can be achieved.

DESCRIPTION OF SYMBOLS 100... Imaging device, 200... Image sensor, 300... Lens module, 1... Position detection apparatus, 3... Driving device, 4... Control part, 5... Lens, 6... Housing, 7... Substrate, 7a... Upper surface, 7K... Opening 11 First magnetic field generator 12 Second magnetic field generator 13, 31A, 34A Magnet 14 First holding member 15 Second holding member 16 First magnetic field generator Wire 17 Second wire 20, 30 Magnetic sensor 41 to 46 Coil 150 MR element 162 Lower electrode 163 Upper electrode 151 Magnetization free layer 152 Nonmagnetic layer 153 Magnetization fixed layer 154 Antiferromagnetic layer MF1 First magnetic field MF2 Second magnetic field MF Composite magnetic field.

Claims (20)

a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is movably provided along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor; have
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator ,
The first magnet and the second magnet each have a first surface that forms an angle of 90±5° with respect to the plane and an angle of 45±5° with respect to the first direction; including a vertex that intersects a second plane that forms an angle of 90 ± 5° with respect to the plane and forms an angle of 90 ± 5° with respect to the first surface;
an angle between the second surface of the first magnet and the second surface of the second magnet is 90±5°;
The first magnet and the second magnet are arranged in a posture that minimizes the distance from the magnetic sensor at each of the vertexes,
Satisfies the following conditional expression (1)
Position detection device.
0<D<(G×2/5) ……(1)
however,
D: Distance from the intermediate position between the vertex of the first magnet and the vertex of the second magnet in the first direction to the center position of the magnetic sensor
G: the distance between the apex of the first magnet and the apex of the second magnet in the first direction
is. 2. The position detection device according to claim 1, which satisfies the following conditional expression (2).
(G/6)<D<(G/3) ……(2) a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is movably provided along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
has
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator,
The first magnet and the second magnet respectively have a first plane that forms an angle of 90±5° with respect to the plane and along the first direction and a plane that is 90±5° with respect to the plane. and a second surface including a portion that forms an angle of 45 ± 5° or less with respect to the first surface;
The second surface of the first magnet and the second surface of the second magnet face each other in the first direction, and the first surface of the first magnet and the second surface of the second magnet face each other in the first direction. are provided so as to separate from each other in the first direction as the distance from the first surface of the magnet is increased,
Satisfies the following conditional expression (3)
Position detection device.
0<D<(G/4) ……(3)
however,
D: Distance from the intermediate position between the first magnet and the second magnet in the first direction to the center position of the magnetic sensor
G: minimum spacing between the first magnet and the second magnet in the first direction
is. 4. The position detection device according to claim 3, which satisfies the following conditional expression (4).
(G/12)<D<(G/5) ……(4) a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is movably provided along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
has
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator,
Both the first magnet and the second magnet are mainly composed of a first magnetic material and have a first shape,
The position detecting device , wherein the second magnetic field generating section includes a third magnet having a second shape and having a second magnetic material as a main component . 6. The position detecting device according to claim 5 , wherein the absolute value of the temperature coefficient of the second residual magnetic flux density in the second magnetic material is smaller than the absolute value of the temperature coefficient of the first residual magnetic flux density in the first magnetic material. . the first magnetic material comprises NdFeB;
7. The position detecting device according to claim 5 , wherein the second magnetic material contains SmCo. All parts of the magnetic sensor are positioned in the first direction at intermediate positions between the first magnet and the second magnet in the area between the first magnet and the second magnet. located in a position other than
The position detection device according to any one of claims 1 to 7 . The second magnetic field generating section is configured such that a part of the second magnetic field generating section exists in an intermediate position between the first magnet and the second magnet in the first direction. located in the region between one magnet and the second magnet
The position detection device according to any one of claims 1 to 7 . A center position of the second magnetic field generating section in the first direction is located at an intermediate position between the first magnet and the second magnet in the first direction.
The position detection device according to any one of claims 1 to 7 . a first holding member that holds the first magnetic field generator;
and a second holding member that is movably provided along the second direction with respect to the first holding member and holds the second magnetic field generating section . 1. The position detection device according to claim 1. The position detection device according to claim 11 , wherein the second holding member can hold a lens having an optical axis along the second direction. The position detection device according to any one of claims 1 to 12 , wherein the magnetic sensor has a sensitivity axis parallel to a plane perpendicular to the second direction. a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is provided movably along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
a lens movably provided along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator;
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator ,
The first magnet and the second magnet each have a first surface that forms an angle of 90±5° with respect to the plane and an angle of 45±5° with respect to the first direction; including a vertex that intersects a second plane that forms an angle of 90 ± 5° with respect to the plane and forms an angle of 90 ± 5° with respect to the first surface;
an angle between the second surface of the first magnet and the second surface of the second magnet is 90±5°;
The first magnet and the second magnet are arranged in a posture that minimizes the distance from the magnetic sensor at each of the vertexes,
Satisfies the following conditional expression (1)
lens module.
0<D<(G×2/5) ……(1)
however,
D: Distance from the intermediate position between the vertex of the first magnet and the vertex of the second magnet in the first direction to the center position of the magnetic sensor
G: the distance between the apex of the first magnet and the apex of the second magnet in the first direction
is. a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is provided movably along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
a lens movably provided along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator;
has
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator,
The first magnet and the second magnet respectively have a first plane that forms an angle of 90±5° with respect to the plane and along the first direction and a plane that is 90±5° with respect to the plane. and a second surface including a portion that forms an angle of 45 ± 5° or less with respect to the first surface;
The second surface of the first magnet and the second surface of the second magnet face each other in the first direction, and the first surface of the first magnet and the second surface of the second magnet face each other in the first direction. are provided so as to separate from each other in the first direction as the distance from the first surface of the magnet is increased,
Satisfies the following conditional expression (3)
lens module.
0<D<(G/4) ……(3)
however,
D: Distance from the intermediate position between the first magnet and the second magnet in the first direction to the center position of the magnetic sensor
G: minimum spacing between the first magnet and the second magnet in the first direction
is. a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is provided movably along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
a lens movably provided along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator;
has
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator,
Both the first magnet and the second magnet are mainly composed of a first magnetic material and have a first shape,
The second magnetic field generator includes a third magnet having a second shape and having a second magnetic material as a main component.
lens module. a first holding member that holds the first magnetic field generator;
provided movably along the second direction with respect to the first holding member,
17. The lens module according to any one of claims 14 to 16, further comprising a second holding member that holds the second magnetic field generator and the lens. an imaging device;
with a lens module and
The lens module is
a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is provided movably along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
a lens movably provided along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator;
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator ,
The first magnet and the second magnet each have a first surface that forms an angle of 90±5° with respect to the plane and an angle of 45±5° with respect to the first direction; including a vertex that intersects a second plane that forms an angle of 90 ± 5° with respect to the plane and forms an angle of 90 ± 5° with respect to the first surface;
an angle between the second surface of the first magnet and the second surface of the second magnet is 90±5°;
The first magnet and the second magnet are arranged in a posture that minimizes the distance from the magnetic sensor at each of the vertexes,
Satisfies the following conditional expression (1)
Imaging device.
0<D<(G×2/5) ……(1)
however,
D: Distance from the intermediate position between the vertex of the first magnet and the vertex of the second magnet in the first direction to the center position of the magnetic sensor
G: the distance between the apex of the first magnet and the apex of the second magnet in the first direction
is. an imaging device;
lens module and
with
The lens module is
a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is provided movably along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
a lens movably provided along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator;
has
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator,
The first magnet and the second magnet respectively have a first plane that forms an angle of 90±5° with respect to the plane and along the first direction and a plane that is 90±5° with respect to the plane. and a second surface including a portion that forms an angle of 45 ± 5° or less with respect to the first surface;
The second surface of the first magnet and the second surface of the second magnet face each other in the first direction, and the first surface of the first magnet and the second surface of the second magnet face each other in the first direction. are provided so as to separate from each other in the first direction as the distance from the first surface of the magnet is increased,
Satisfies the following conditional expression (3)
Imaging device.
0<D<(G/4) ……(3)
however,
D: Distance from the intermediate position between the first magnet and the second magnet in the first direction to the center position of the magnetic sensor
G: minimum spacing between the first magnet and the second magnet in the first direction
is. an imaging device;
lens module and
with
The lens module is
a magnetic sensor;
a first magnetic field generator that generates a first magnetic field including a first magnet and a second magnet spaced apart from each other in a first direction;
a second magnetic field generator that generates a second magnetic field and is provided movably along a second direction orthogonal to the first direction with respect to the first magnetic field generator and the magnetic sensor;
a lens movably provided along the second direction with respect to the first magnetic field generator and the magnetic sensor in conjunction with the second magnetic field generator;
has
In the first direction, the center position of the magnetic sensor is a region between the first magnet and the second magnet other than the intermediate position between the first magnet and the second magnet. in position,
The magnetic sensor generates a detection signal corresponding to the direction of a detection target magnetic field obtained by synthesizing the first magnetic field along a plane orthogonal to the second direction and the second magnetic field along the plane. and can detect a change in the position of the second magnetic field generator,
Both the first magnet and the second magnet are mainly composed of a first magnetic material and have a first shape,
The second magnetic field generator includes a third magnet having a second shape and having a second magnetic material as a main component.
Imaging device.

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