Position detection device, lens module, and imaging apparatus

Abstract

To provide a position detection device having a more compact configuration while securing a predetermined position detection range.SOLUTION: A position detection device includes: a yoke having an extending portion extending in a first axial direction; a first magnetic field generation portion magnetized in a second axial direction intersecting the first axial direction and generating a first magnetic field; a bias magnetic field generation portion provided on a side opposite to the first magnetic field generation portion when viewed from the extending portion of the yoke in the second axial direction and generating a bias magnetic field; and a magnetic field detection portion. The first magnetic field generation portion is movable in the first axial direction with respect to the yoke, the bias magnetic field generation portion, and the magnetic field detection portion. The magnetic field detection portion detects a change in intensity of the first magnetic field in a first direction along the first axial direction.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates to a position detection device, a lens module, and an imaging device that are equipped with a magnetic field detection unit. [Background technology]

[0002] There is known a position detection device that detects the position of a moving object that moves linearly. For example, Patent Document 1 discloses a magnetic position detection device that includes a magnetic sensing element and a plurality of magnetic members attached to the moving object at intervals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-137796 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a demand for such position detection devices to be smaller and lighter in weight.

[0005] Therefore, it is desirable to provide a position detection device that has a more compact configuration while ensuring a predetermined position detection range. [Means for solving the problem]

[0006] A position detection device according to one embodiment of the present disclosure includes a yoke having an extending portion extending in a first axis direction, a first magnetic field generating unit magnetized in a second axis direction intersecting the first axis direction and generating a first magnetic field, a bias magnetic field generating unit provided on the opposite side of the first magnetic field generating unit in the second axis direction as viewed from the extending portion of the yoke, and generating a bias magnetic field, and a magnetic field detecting unit. Here, the first magnetic field generating unit is movable in the first axis direction relative to the yoke, the bias magnetic field generating unit, and the magnetic field detecting unit. The magnetic field detecting unit detects the strength of the first magnetic field in a first direction along the first axis direction. Effect of the Invention

[0007] According to a position detection device according to an embodiment of the present disclosure, a more compact configuration can be realized while ensuring a predetermined position detection range. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 1A is a perspective view illustrating an external appearance of a position detection device according to a first embodiment of the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view illustrating an example of a cross-sectional configuration of the position detection device illustrated in FIG. 1A. [Figure 1C] FIG. 1C is a side view illustrating a first configuration example of the position detection device illustrated in FIG. 1A as viewed from the side. [Figure 1D] FIG. 1D is a side view illustrating a second configuration example of the position detection device illustrated in FIG. 1A as viewed from the side. [Figure 1E] FIG. 1E is a side view illustrating a third configuration example of the position detection device illustrated in FIG. 1A as viewed from the side. [Diagram 2] FIG. 2 is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 1A. [Figure 3A] FIG. 3A is a cross-sectional view illustrating an example of a cross-sectional configuration of a position detection device as a first reference example. [Figure 3B] FIG. 3B is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 2A. [Figure 4A] FIG. 4A is a cross-sectional view illustrating an example of the configuration of a position detection device serving as a first modified example of the first embodiment. [Figure 4B] FIG. 4B is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 4A. [Figure 5A] FIG. 5A is a cross-sectional view illustrating an example of a cross-sectional configuration of a position detection device as a second reference example. [Figure 5B] FIG. 5B is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 5A. [Figure 6] FIG. 6 is a cross-sectional view illustrating an example of the configuration of a position detection device serving as a second modified example of the first embodiment. [Figure 7A] FIG. 7A is a cross-sectional view illustrating a configuration example of a position detection device according to a second embodiment of the present disclosure. [Figure 7B] FIG. 7B is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 7A. [Figure 8A] FIG. 8A is a cross-sectional view illustrating an example of the configuration of a position detection device serving as a first modified example of the second embodiment. [Figure 8B] FIG. 8B is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 8A. [Figure 9A] FIG. 9A is a cross-sectional view illustrating a configuration example of a position detection device according to a third embodiment of the present disclosure. [Figure 9B] FIG. 9B is a side view illustrating a first configuration example of the position detection device illustrated in FIG. 9A as viewed from the side. [Figure 9C] FIG. 9C is a side view illustrating a second configuration example of the position detection device illustrated in FIG. 9A as viewed from the side. [Figure 9D] FIG. 9D is a side view illustrating a third configuration example of the position detection device illustrated in FIG. 9A as viewed from the side. [Figure 10] FIG. 10 is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 9A. [Figure 11A] FIG. 11A is a cross-sectional view illustrating a configuration example of a position detection device according to a fourth embodiment of the present disclosure. [Figure 11B] FIG. 11B is a characteristic diagram showing a change in the strength of the magnetic field applied to the magnetic field generating unit accompanying the movement of the magnetic field generating unit in the position detection device shown in FIG. 11A. [Figure 12]FIG. 12 is a schematic diagram illustrating a configuration example of a position detection device assembly according to the fifth embodiment of the present disclosure. As shown in FIG. [Figure 13A] FIG. 13A is a schematic perspective view illustrating an example of an overall configuration of an imaging device according to a sixth embodiment of the present disclosure. [Figure 13B] FIG. 13B is a schematic perspective view illustrating an example of the overall configuration of an imaging device according to the seventh embodiment of the present disclosure. [Figure 14] FIG. 14 is a schematic side view illustrating an example of the overall configuration of a position detection device according to another modified example of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The description will be given in the following order. 1. First embodiment and its modified examples 13 is an example of a position detector including one partial annular yoke, one magnetic field generating unit, one magnetic field detecting unit, and one bias magnetic field generating unit. 2. Second embodiment and its modified example 13 is an example of a position detector including a partial annular yoke having two cutouts, one magnetic field generating unit, two magnetic field detecting units, and one bias magnetic field generating unit. 3. Third embodiment and its modified example 13 is an example of a position detection device including two position detection units, each of which has a partial annular yoke having one notch, one magnetic field generating unit, and one magnetic field detecting unit. 4. Fourth embodiment and its modified examples Another example of a position detection device including a partial annular yoke having two cutouts, one magnetic field generating unit, two magnetic field detecting units, and one bias magnetic field generating unit. 5. Fifth embodiment 13 is an example of a position detection device assembly equipped with a position detection device. 6. Sixth embodiment 1 shows a first example of an imaging device that includes the position detection device of the first embodiment and a lens and detects the position of the lens. 7. Seventh embodiment 2 shows a second example of an imaging device that includes the position detection device of the first embodiment and a lens, and detects the position of the lens. 8. Other Modifications

[0010] <1. First embodiment> [Configuration of position detection device 1] First, the configuration of a position detection device 1 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1A to 1E.

[0011] FIG. 1A is a perspective view showing an example of the overall configuration of the position detection device 1. FIG. 1B is a cross-sectional view showing an example of the cross-sectional configuration of the position detection device 1. Furthermore, FIGS. 1C to 1E are side views showing first to third configuration examples of the position detection device 1 when viewed from the side in the -X direction, respectively. The X-axis direction, Z-axis direction, and Y-axis direction shown in FIGS. 1A to 1E are specific examples corresponding to the "first axis direction," the "second axis direction," and the "third axis direction" as one aspect of the present disclosure, respectively. The X-axis direction, Z-axis direction, and Y-axis direction are mutually orthogonal. In this specification, "orthogonal" is not limited to a state where the directions cross at a strict 90° geometrically, but also includes a state where the directions cross within a range of, for example, 90±10°. In this specification, a position on the +Z side or a direction on the +Z side as viewed from an arbitrary member or part may be described as an upper side, and a position on the -Z side or a direction on the -Z side as viewed from the member or part may be described as a lower side.

[0012] As shown in FIGS. 1A and 1B, the position detection device 1 includes a magnet 10, a magnetic field sensor 20, a partial annular yoke 30, and a bias magnet 40. The magnet 10, the magnetic field sensor 20, the partial annular yoke 30, and the bias magnet 40 are specific examples corresponding to the "first magnetic field generating unit", the "magnetic field detecting unit", the "yoke", and the "bias magnetic field generating unit" as one aspect of the present disclosure. The magnet 10 generates a magnetic field that reaches the magnetic field sensor 20. The magnetic field sensor 20 detects the intensity of the component in the +X direction, for example, of the magnetic field generated by the magnet 10. The magnetic field generated by the magnet 10 is concentrated in the partial annular yoke 30, and the magnetic field lines ML pass through the partial annular yoke 30 as shown in FIG. 1B. In addition, a notch 30K is provided in the annular yoke 30. The magnetic field sensor 20 is disposed in the notch 30K. Therefore, the magnetic field lines ML also pass through the magnetic field sensor 20. 1A and 1B, the magnet 10 and the partial annular yoke 30 face each other with a space therebetween in the Z-axis direction. For convenience, the present embodiment will be described assuming that the annular yoke 30 and the magnetic field sensor 20 are relatively positioned above the magnet 10, and the magnet 10 is relatively positioned below the partial annular yoke 30 and the magnetic field sensor 20.

[0013] (Partial annular yoke 30) The partial annular yoke 30 has a first yoke part YK1 and a second yoke part YK2 which are parts of an annular object rotating in the rotation direction R (FIG. 1B) within the XZ plane, for example. The first yoke part YK1 and the second yoke part YK2 face each other so as to sandwich the magnetic field sensor 20 and the bias magnet 40 in the Z-axis direction. The partial annular yoke 30 also has a notch 30K in a part of the rotation direction R. The position of the notch 30K is not limited to the position shown in FIGS. 1A and 1B, and can be selected arbitrarily.

[0014] A part of the partial annular yoke 30 is separated by the bias magnet 40. Alternatively, a part of the partial annular yoke 30 is replaced by the bias magnet 40. That is, the bias magnet 40 is disposed between the first yoke part YK1 and the second yoke part YK2 along the circumferential direction R in which the partial annular yoke 30 rotates. The partial annular yoke 30 has a generally bent shape so as to surround the space 30V along the XZ plane together with the bias magnet 40. The magnetic field sensor 20 is provided in the notch 30K of the partial annular yoke 30. The partial annular yoke 30 includes a pair of facing parts 31, 32 that face each other with the magnetic field sensor 20 therebetween, and a pair of extending parts 33, 36 that extend, for example, linearly along the X-axis direction. The facing part 31 and the extending part 36 are magnetically connected to each other to form the first yoke part YK1, and the facing part 32 and the extending part 33 are magnetically connected to each other to form the second yoke part YK2. In the example shown in Figures 1A and 1B, the facing portion 31 and the facing portion 32 are arranged to face each other in the Z-axis direction, and the extending portion 33 and the extending portion 36 are arranged to face each other in the Z-axis direction. The cross-sectional areas of the cross sections perpendicular to the rotation direction R in each of the facing portions 31 and 32 and the extending portions 33 and 36 can be substantially constant. Of the extending portion 36, a second end opposite to the first end connected to the facing portion 31 is magnetically connected to, for example, the S pole of the bias magnet 40. Of the extending portion 33, a second end opposite to the first end connected to the facing portion 32 is magnetically connected to the N pole of the bias magnet 40.

[0015] In FIG. 1B, position -S2 represents the position of the end of the partial annular yoke 30 (a pair of extending portions 33, 36) on the -X side, and position +S2 represents the position of the end of the partial annular yoke 30 (a pair of opposing portions 31, 32) on the +X side. Position S0 is the center position of the partial annular yoke 30 in the X-axis direction. Position -S1 is the center position of the bias magnet 40 in the X-axis direction. Position +S1 represents the position of the end of the pair of extending portions 33, 36 on the +X side. The partial annular yoke 30 is made of a soft ferromagnetic material such as permalloy (NiFe), and guides the magnetic field lines ML toward the magnetic field sensor 20.

[0016] (Magnet 10) The magnet 10 is a permanent magnet having, for example, an approximately rectangular parallelepiped shape. The magnet 10 is disposed on the opposite side of the space 30V from the extension portion 33. The magnet 10 is mainly composed of a ferromagnetic material. Specifically, examples of the ferromagnetic material used for the magnet 10 include neodymium-based magnet materials such as NdFeB and rare earth magnet materials such as SmCo. As shown in FIG. 1C, the magnet 10 overlaps with the partial annular yoke 30 in the Z-axis direction. In detail, the magnet 10 faces the extension portion 33 of the partial annular yoke 30 in the Z-axis direction. Here, the magnet 10 facing the extension portion 33 in the Z-axis direction means that at least a part of the magnet 10 overlaps with the extension portion 33 in the Z-axis direction. In the position detection device 1, it is particularly preferable that the magnet 10 is directly below the extension portion 33 in the Z-axis direction, as shown in FIG. 1C. That is, in the Y-axis direction, the center position 10PY of the magnet 10 in the Y-axis direction should coincide with the center position 33PY of the extension portion 33 in the Y-axis direction. This is because the magnetic field lines ML are more efficiently guided to the partial annular yoke 30. However, in the position detection device 1, the center position 10PY of the magnet 10 may be offset from the center position 33PY of the extension portion 33 in the Y-axis direction, as shown in, for example, FIG. 1D and FIG. 1E, respectively. When the center position 10PY of the magnet 10 is offset from the center position 33PY of the extension portion 33, the center position 10PY of the magnet 10 should be in a position overlapping a part of the extension portion 33 in the Z-axis direction. That is, more than half of the magnet 10 should overlap a part of the extension portion 33 in the Z-axis direction. The magnet 10 is provided so as to be reversibly movable in the X-axis direction relative to the magnetic field sensor 20 and the partial annular yoke 30. 1B, magnet 10 is reversibly movable along the X-axis direction, for example, from position -S1 to position +S1, with initial position S0 as the center. That is, magnet 10 is movable in the -X direction from position S0 until its center position in the X-axis direction reaches position -S1, and is also movable in the +X direction from position S0 until it reaches position +S1. Therefore, magnet 10 is movable in the X-axis direction within a range facing extension portion 33 in the Z-axis direction.

[0017] The magnet 10 is magnetized in the +Z direction along the Z-axis direction, for example. More specifically, the side of the magnet 10 facing the partial annular yoke 30 is an N pole, and the side opposite the annular yoke 30 is an S pole. However, the present disclosure is not limited to the case where the magnetization direction of the magnet 10 strictly coincides with the +Z direction, and also allows the magnetization direction of the magnet 10 to be inclined by about 5 to 10 degrees with respect to the +Z direction.

[0018] (Magnetic Field Sensor 20) The magnetic field sensor 20 is provided on the opposite side of the magnet 10 in the Z-axis direction as viewed from the extension portion 33. The magnetic field sensor 20 detects a magnetic field component parallel to the Z-axis of the magnetic field applied to itself, and generates a detection signal corresponding to the intensity of the magnetic field component parallel to the Z-axis. In the position detection device 1, the output signal from the magnetic field sensor 20 changes as the position of the magnet 10 in the X-axis direction changes within a range from position -S1 to position +S1 relative to the magnetic field sensor 20 and the partial annular yoke 30. That is, the magnetic field sensor 20 is configured to indicate a characteristic value (e.g., a Hall voltage) according to the position of the magnet 10 in the X-axis direction relative to the magnetic field sensor 20. Therefore, the magnetic field sensor 20 can detect the position of the magnet 10 in the X-axis direction between position -S1 and position +S1. In the example of the position detection device 1 shown in FIG. 1A and FIG. 1B, the magnetic field sensor 20 is provided in the vicinity of an end of the partial annular yoke 30 on the opposite side to the position where the bias magnet 40 is arranged in the X-axis direction.

[0019] FIG. 2 is a characteristic diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction applied to the magnetic field sensor 20 in the position detection device 1. Specifically, FIG. 2 shows the magnetic field strength in the +Z direction applied to the magnetic field sensor 20 when the magnet 10 moves from position S0 to position -S2 in the -X direction in the position detection device 1, and the magnetic field strength in the +Z direction applied to the magnetic field sensor 20 when the magnet 10 moves from position S0 to position +S2 in the +X direction in the position detection device 1. The horizontal axis of FIG. 2 represents the position of the magnet 10 in the X-axis direction, and the vertical axis of FIG. 2 represents the magnetic field strength in the +Z direction applied to the magnetic field sensor 20. The characteristic diagram of FIG. 2 shows the results of a simulation using a computer. The conditions of the simulation are as follows. The dimensions of the magnet 10 in the X-axis direction, Y-axis direction, and Z-axis direction are 10 mm, 10 mm, and 6 mm, respectively. The magnetization direction of the magnet 10 is the +Z direction. The magnetic properties of magnet 10 are: residual magnetic flux density Br is 1300 mT, coercive force Hcb is 979 kA / m, coercive force Hcj is 1671 kA / m, and maximum energy product BH is 326 kJ / m. 3The distance in the Z-axis direction between the magnet 10 and the partial annular yoke 30 is 3 mm. The distance in the Z-axis direction between the facing portion 31 and the facing portion 32 of the partial annular yoke 30 is 3 mm. The dimension in the Z-axis direction of the extension portion 36 and the extension portion 33 is 2 mm. The dimension in the X-axis direction of the facing portions 31 and 32 is 2 mm. The dimension in the Y-axis direction of the facing portion 31, the facing portion 32, the extension portion 36 and the extension portion 33 is 5 mm. The distance in the Z-axis direction between the extension portion 36 and the extension portion 33 is 6 mm. Therefore, the dimension in the Z-axis direction of the entire partial annular yoke 30 is 10 mm. The dimension in the X-axis direction of the entire partial annular yoke 30, i.e., the length from position -S2 to position +S2, is 100 mm, and the length from position -S1 to position +S1 is 92 mm. The dimensions of the bias magnet 40 in the X-axis, Y-axis, and Z-axis directions are 5 mm, 5 mm, and 10 mm, respectively. The magnetization direction of the bias magnet 40 is the -Z direction. The magnetic properties of the bias magnet 40 are a residual magnetic flux density Br of 1300 mT, a coercive force Hcb of 979 kA / m, a coercive force Hcj of 1671 kA / m, and a maximum energy product BH of 326 kJ / m. 3 Furthermore, the +Z direction is defined as the positive magnetization direction of the magnet 10, the +X direction is defined as the positive detection direction of the magnetic field sensor 20, and the +X direction is defined as the positive movement direction of the magnet 10. Furthermore, the set temperature is defined as 140°C.

[0020] 2, in the range from position -S1 to position +S1, the relationship between the position in the X-axis direction and the magnetic field strength in the +Z direction is approximately linear. Since the magnetic field sensor 20 indicates a characteristic value (e.g., Hall voltage) according to the magnitude of the magnetic field strength in the +Z direction, the position of the magnet 10 in the X-axis direction is identified by detecting an output signal based on the characteristic value (e.g., Hall voltage) of the magnetic field sensor 20.

[0021] The magnetic field sensor 20 is, for example, a Hall IC in which a Hall element and a circuit including an operational amplifier are integrated. The Hall element is a device that exhibits the Hall effect, and when a magnetic field in the X-axis direction is applied while a current is flowing, it generates a Hall voltage in a direction perpendicular to both the direction of the current and the direction of the magnetic field (Z-axis direction). This Hall voltage is proportional to the strength of the magnetic field. Since the Hall voltage is very small, it is desirable to amplify it using an operational amplifier.

[0022] (Bias magnet 40) The bias magnet 40 is sandwiched between the extension portion 33 and the extension portion 36 at the end of the partial annular yoke 30 opposite to the notch 30K. The bias magnet 40 is a permanent magnet having an appearance of, for example, a substantially rectangular parallelepiped shape. The bias magnet 40 is mainly composed of a ferromagnetic material. Specifically, examples of the ferromagnetic material used for the bias magnet 40 include neodymium-based magnet materials such as NdFeB and rare earth magnet materials such as SmCo. The bias magnet 40 overlaps with a part of the extension portion 33 and a part of the extension portion 36 in the Z-axis direction. The bias magnet 40 is magnetized along the circumferential direction R of the partial annular yoke 30, and in this embodiment, is magnetized in the -Z direction along the Z-axis direction. More specifically, in the bias magnet 40, the side facing the extension portion 36 is an S pole, and the side facing the extension portion 33 is an N pole. However, the present disclosure is not limited to the case where the magnetization direction of the bias magnet 40 strictly coincides with the -Z direction, but also allows the magnetization direction of the bias magnet 40 to be inclined by about 5 to 10 degrees with respect to the -Z direction.

[0023] [Functions and Effects of Position Detection Device 1] As described above, the position detection device 1 according to the present embodiment includes the partial annular yoke 30 having the extension portion 33 extending in the X-axis direction, the magnet 10 magnetized in the Z-axis direction to generate a magnetic field, the bias magnet 40 provided on the opposite side of the magnet 10 in the Z-axis direction as viewed from the extension portion 33 to generate a bias magnetic field, and the magnetic field sensor 20. Here, the magnet 10 is movable in the X-axis direction relative to the partial annular yoke 30, the bias magnet 40, and the magnetic field sensor 20. The magnetic field sensor 20 detects the strength of the magnetic field component in the +Z direction of the magnetic field generated by the magnet 10. In the position detection device 1 configured as above, as shown in FIG. 1C, the relationship between the position in the X-axis direction and the magnetic field strength in the +Z direction is approximately linear in the range from position -S1 to position +S1. Therefore, the position detection device 1 can detect the position of the magnet 10 in the X-axis direction within the range in which the extension portion 33 is provided in the X-axis direction.

[0024] In the position detection device 1, the movement range of the magnet 10 is only between the positions −S1 and +S1, which are both ends of the extension portion 33 extending along the X-axis direction, so that the size of the position detection device 1 in the X-axis direction does not change with the movement of the magnet 10. Furthermore, in the position detection device 1, the magnet 10 is moved in the X-axis direction, which is the extension direction of the extension portion 33 of the partial annular yoke 30, so that the distance between the extension portion 33 and the magnet 10 can be kept substantially constant. Therefore, a sufficient magnetic field can be applied to the magnetic field sensor 20 without increasing the volume (magnetic volume) of the magnet 10. That is, the size of the magnet 10 can be minimized. Therefore, the position detection device 1 can detect the position and the amount of movement of the magnet 10 within the volume occupied by the position detection device 1, even if the installation area is limited. In other words, according to the position detection device 1, the position and the amount of movement of the magnet 10 and the object to which the magnet 10 is attached can be detected within the range of the installation area.

[0025] Furthermore, since the position detection device 1 is provided with the bias magnet 40, the strength of the magnetic field applied to the magnetic field sensor 20 can be increased.

[0026] FIG. 3A is a cross-sectional view showing an example of the overall configuration of the position detection device 101 as Reference Example 1. The position detection device 101 includes a partial annular yoke 130 instead of the partial annular yoke 30, and does not include a bias magnet 40. Except for these points, the configuration of the position detection device 101 is substantially the same as that of the position detection device 1. The partial annular yoke 130 further includes a connecting portion 34 in addition to a pair of facing portions 31 and 32 and a pair of extending portions 33 and 36. The connecting portion 34 is provided so as to magnetically connect a second end portion of the extending portion 36 opposite to a first end portion connected to the facing portion 31, and a second end portion of the extending portion 33 opposite to a first end portion connected to the facing portion 32. Note that the position -S1 in FIG. 2A represents the position of the end portion on the -X side of the extending portions 33 and 36. FIG. 3B is a characteristic diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction reaching the magnetic field sensor 20 in the position detection device 101 as Reference Example 1. Specifically, FIG. 2B shows the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20 when the magnet 10 moves from position S0 to position -S2 in the -X direction in the position detection device 101, and the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20 when the magnet 10 moves from position S0 to position +S2 in the +X direction. The characteristic diagram in FIG. 3B shows the results of a simulation using a computer. The simulation conditions are as follows. The simulation conditions in FIG. 3B are basically the same as those in FIG. 2. However, they differ from the simulation conditions in FIG. 2 in the following respects. The dimension of the connecting portion 34 of the partial annular yoke 30A in the X-axis direction is 2 mm. The dimension of the connecting portion 34 in the Y-axis direction is 5 mm.

[0027] Here, a comparison is made between the characteristic diagram of the position detection device 1 (FIG. 2) and the characteristic diagram of the position detection device 101 (FIG. 3B). As shown in FIG. 3B, in the position detection device 101 as well, in the range from position -S1 to position +S1, the strength of the magnetic field in the +Z direction changes monotonically with respect to the change in position in the X-axis direction. However, in the characteristic diagram of the position detection device 1 shown in FIG. 2, the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20 is higher, especially in the range from position S0 to position +S1.

[0028] In this way, since the position detection device 1 is equipped with the bias magnet 40, the strength of the magnetic field applied to the magnetic field sensor 20 can be increased, and the position of the magnet 10 in the X-axis direction can be detected even if the magnetic volume of the magnet 10 is reduced.

[0029] [Variation 1-1] FIG. 4A is a cross-sectional view illustrating an example of the overall configuration of a position detection device 1A as a first modified example (modified example 1-1) of the present embodiment, and corresponds to FIG. 1B illustrating the position detection device 1 of the above-described first embodiment.

[0030] In the above-described position detector 1, the partial annular yoke 30 has the first yoke portion YK1 and the second yoke portion YK2 that face each other so as to sandwich the magnetic field sensor 20 and the bias magnet 40 in the Z-axis direction, but the present disclosure is not limited to this. The position detector 1A includes a partial annular yoke 30A that has only the second yoke portion YK2 of the first yoke portion YK1 and the second yoke portion YK2.

[0031] FIG. 4B is a characteristic diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction reaching the magnetic field sensor 20 in the position detection device 1A, and corresponds to FIG. 2 showing the characteristic diagram of the position detection device 1 in the first embodiment. The characteristic diagram of FIG. 4B shows the result of a simulation using a computer. The conditions of the simulation of FIG. 4B are the same as those of the simulation of FIG. 3B, except for the conditions related to the first yoke part YK1. As shown in FIG. 4B, in the position detection device 1A as well, the relationship between the position in the X-axis direction and the magnetic field strength in the +Z direction is approximately linear in the range from position -S1 to position +S1. Therefore, in the position detection device 1A as well, the position of the magnet 10 in the X-axis direction can be detected within the range in which the extension part 33 is provided in the X-axis direction.

[0032] In addition, since the position detection device 1A is provided with the bias magnet 40, the strength of the magnetic field applied to the magnetic field sensor 20 can be increased compared to the position detection device 101A (FIG. 5A) of Reference Example 2 that does not have the bias magnet 40. FIG. 5A is a cross-sectional view showing an example of the overall configuration of the position detection device 101A of Reference Example 2. The position detection device 101A does not have the bias magnet 40. Except for this point, the configuration of the position detection device 101A is substantially the same as that of the position detection device 1A. FIG. 5B is a characteristic diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction reaching the magnetic field sensor 20 in the position detection device 101A of Reference Example 2. Specifically, FIG. 5B shows the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20 when the magnet 10 moves from position S0 to position -S2 in the -X direction in the position detection device 101A, and the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20 when the magnet 10 moves from position S0 to position +S2 in the +X direction. The characteristic diagram of FIG. 5B shows the result of a simulation using a computer. The conditions of the simulation of FIG. 5B are the same as those of the simulation of FIG. 3B, except for the conditions related to the first yoke part YK1 and the bias magnet 40. As shown in FIG. 5B, in the position detection device 101, the magnetic field strength in the +Z direction changes monotonically with respect to the change in position in the X-axis direction in the range from position -S1 to position +S1. However, the characteristic diagram of the position detection device 1A shown in FIG. 4B shows that the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20 is higher, especially in the range from position S0 to position +S1.

[0033] In this way, since the position detection device 1A is equipped with the bias magnet 40, the strength of the magnetic field applied to the magnetic field sensor 20 can be increased, and the position of the magnet 10 in the X-axis direction can be detected even if the magnetic volume of the magnet 10 is reduced.

[0034] [Variation 1-2] FIG. 6 is a cross-sectional view showing an example of the overall configuration of a position detection device 1B as a second modified example (modified example 1-2) of the present embodiment, and corresponds to FIG. 1B showing the position detection device 1 of the above-described first embodiment.

[0035] In the position detection device 1B as the modified example 1-2, a back yoke 11 is further provided on the opposite side of the magnet 10 to the partial annular yoke 30. The back yoke 11 is made of, for example, a soft magnetic material similar to the partial annular yoke 30. By providing the back yoke 11, the strength of the magnetic field applied to the magnetic field sensor 20 can be further increased.

[0036] <2. Second embodiment> [Configuration of position detection device 2] Next, a configuration of a position detection device 2 according to a second embodiment of the present disclosure will be described with reference to FIGS. 7A and 7B.

[0037] Fig. 7A is a cross-sectional view showing an example of the overall configuration of the position detection device 2 of this embodiment, and corresponds to Fig. 1B showing the position detection device 1 of the first embodiment. Fig. 7B is a characteristics diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction reaching the magnetic field sensor 20 in the position detection device 2, and corresponds to Fig. 2 showing the characteristics diagram of the position detection device 1 of the first embodiment. The characteristics diagram of Fig. 7B shows the results of a simulation using a computer.

[0038] In the position detection device 1 of the first embodiment, one notch 30K is provided in the partial annular yoke 30, and one magnetic field sensor 20 is arranged in the notch 30K. In contrast, in the position detection device 2 of the present embodiment, a partial annular yoke 30B is provided instead of the partial annular yoke 30. The partial annular yoke 30B is provided with two notches 30K1 and 30K2. The notch 30K1 is provided at the end of the partial annular yoke 30B on the +X side in the X-axis direction, and the notch 30K2 is provided at the end of the partial annular yoke 30B on the -X side in the X-axis direction. The magnetic field sensor 20A is arranged in the notch 30K1, and the magnetic field sensor 20B is arranged in the notch 30K2. The magnetic field sensors 20A and 20B each have substantially the same configuration as the magnetic field sensor 20 described in the first embodiment. The partial annular yoke 30B has a pair of facing parts 31, 32, an extension part 33, a pair of facing parts 37, 38, and extension parts 36A, 36B. In the partial annular yoke 30B, the pair of facing parts 31, 32 face each other across the magnetic field sensor 20A in the Z-axis direction, and the pair of facing parts 37, 38 face each other across the magnetic field sensor 20B in the Z-axis direction. The extension parts 36A, 36B extend in the X-axis direction while facing the extension part 33 in the Z-axis direction. The extension parts 36A, 36B are located on the opposite side of the magnet 10 in the Z-axis direction as viewed from the extension part 33. A bias magnet 40 is provided between the extension part 36A and the extension part 36B. The bias magnet 40 is magnetized in, for example, the +Z direction. The magnetic field generated by the magnet 10 is concentrated in the partial annular yoke 30B, and as shown in FIG. 7A, the magnetic field lines ML pass through the partial annular yoke 30B. The magnetic field lines ML also pass through the magnetic field sensors 20A and 20B provided in the cutouts 30K1 and 30K2, respectively.

[0039] [Function and effect of position detection device 2] The conditions of the simulation in FIG. 7B are basically the same as those of the simulation in FIG. 2. However, the simulation conditions differ from those in FIG. 2 in the following respects. The distance in the Z-axis direction between the opposing parts 37 and 38 of the partial annular yoke 30B is 3 mm. The dimension in the X-axis direction of each of the opposing parts 37 and 38 is 2 mm. The dimension in the Y-axis direction of each of the opposing parts 37 and 38 is 5 mm. Furthermore, the distance in the X-axis direction between the extension parts 36A and 36B is 10 mm. The magnetization direction of the bias magnet 40 is the −X direction. As shown in FIG. 7B, in the position detection device 2, there is a region in which the strength of the magnetic field in the +Z direction applied to the magnetic field sensors 20A and 20B changes monotonically depending on the position of the magnet 10 in the X-axis direction. Specifically, in FIG. 7B, the curve drawn by the thick line L1 represents the change in the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20A, and the curve drawn by the thin line L2 represents the change in the strength of the magnetic field in the +Z direction applied to the magnetic field sensor 20B. For the magnetic field sensor 20A, the magnetic field strength in the +Z direction has a relatively high linearity in the range from position S0 to position +S1. On the other hand, for the magnetic field sensor 20B, the magnetic field strength in the +Z direction has a relatively high linearity in the range from position S0 to position -S1. Therefore, in the position detection device 2, when the magnet 10 is in the range from position S0 to position +S1, the position of the magnet 10 in the X-axis direction can be identified by detecting an output signal based on a characteristic value (e.g., Hall voltage) of the magnetic field sensor 20A. On the other hand, when the magnet 10 is in the range from position S0 to position -S1, the position of the magnet 10 in the X-axis direction can be identified by detecting an output signal based on a characteristic value (e.g., Hall voltage) of the magnetic field sensor 20B.

[0040] [Variation 2-1] FIG. 8A is a cross-sectional view illustrating an example of the overall configuration of a position detection device 2A as a first modified example (modified example 2-1) of this embodiment, and corresponds to FIG. 7A illustrating the position detection device 2 of the second embodiment.

[0041] In a position detection device 2A as a modified example 2-1, a back yoke 11 is further provided on the opposite side of the magnet 10 to the partial annular yoke 30. The back yoke 11 is made of a soft magnetic material, for example, similar to the partial annular yoke 30.

[0042] Fig. 8B is a characteristic diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction reaching the magnetic field sensor 20 in the position detection device 2A, and corresponds to Fig. 7B showing the characteristic diagram of the position detection device 2 of the second embodiment. The characteristic diagram of Fig. 8B shows the results of a simulation using a computer. The simulation conditions are the same as those of Fig. 7B. However, the dimensions of the back yoke 11 in the X-axis direction, Y-axis direction, and Z-axis direction are 5 mm, 5 mm, and 1.5 mm, respectively.

[0043] In the position detection device 2A as this modified example, the back yoke 11 is provided, so that the strength of the magnetic field applied to the magnetic field sensor 20 can be further increased.

[0044] <3. Third embodiment> [Configuration of position detection device 3] Next, a configuration of a position detection device 3 according to a third embodiment of the present disclosure will be described with reference to FIGS. 9A and 9B.

[0045] Fig. 9A is a cross-sectional view showing an example of the overall configuration of the position detection device 3 of this embodiment, and corresponds to Fig. 1B showing the position detection device 1 of the first embodiment. Figs. 9B to 9D are side views showing first to third configuration examples of the position detection device 3 as viewed from the side in the -X direction, respectively. Fig. 10 is a characteristics diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction in the position detection device 3 and the strength of the magnetic field in the +Z direction that extends to the magnetic field sensors 20-1 and 20-2, and corresponds to Fig. 2 showing the characteristics diagram of the position detection device 1 of the first embodiment.

[0046] The position detection device 3 includes a first unit U1 and a second unit U2. The configurations of the first unit U1 and the second unit U2 are substantially the same as, for example, the configuration of the position detection device 1 of the first embodiment. However, the magnet 10 is shared by the first unit U1 and the second unit U2. That is, the first unit U1 includes the magnet 10, a magnetic field sensor 20-1, a partial annular yoke 30-1, and a bias magnet 40-1. The magnet 10 is a first magnetic field generating unit that generates a first magnetic field. The magnetic field sensor 20-1 detects the intensity of the first magnetic field generated by the magnet 10 in the +Z direction. The partial annular yoke 30-1 is provided with a notch 30K-1, and the magnetic field sensor 20-1 is disposed in the notch 30K-1. Similarly, the second unit U2 includes the magnet 10, a magnetic field sensor 20-2, a partial annular yoke 30-2, and a bias magnet 40-2. The magnetic field sensor 20-2 detects the intensity in the +Z direction of the first magnetic field generated by the magnet 10. The partial annular yoke 30-2 is provided with a notch 30K-2, and the magnetic field sensor 20-2 is disposed in the notch 30K-2. As shown in FIG. 9B, the first unit U1 and the second unit U2 are arranged adjacent to each other in the Z-axis direction. In detail, the magnet 10 faces both the extension portion 33-1 of the partial annular yoke 30-1 and the extension portion 33-2 of the partial annular yoke 30-2 in the Z-axis direction. Here, the magnet 10 faces both the extension portion 33-1 and the extension portion 33-2 in the Z-axis direction, meaning that at least a part of the magnet 10 overlaps both the extension portion 33-1 and the extension portion 33-2 in the Z-axis direction. In the position detector 1, in particular, as shown in FIG. 9B, in the Y-axis direction, it is preferable that the center position 10PY of the magnet 10 in the Y-axis direction coincides with both the center position 33-1PY in the Y-axis direction of the extension portion 33-1 and the center position 33-2PY in the Y-axis direction of the extension portion 33-2. This is because the magnetic field lines ML are more efficiently guided to the partial annular yoke 30. However, in the position detection device 3, the center position 10PY of the magnet 10 may be offset from at least one of the center positions 33-1PY and 33-2PY in the Y-axis direction, as shown in, for example, Figures 9C and 9D, respectively. When the center position 10PY of the magnet 10 is offset from at least one of the center positions 33-1PY and 33-2PY, it is preferable that the center position 10PY of the magnet 10 is located at a position overlapping with a part of the extension portion 33-1 and a part of the extension portion 33-2 in the Z-axis direction. In particular, it is preferable that all parts of the magnet 10 overlap with both a part of the extension portion 33-1 and a part of the extension portion 33-2 in the Z-axis direction.

[0047] In the position detection device 3, the magnet 10 is reversibly movable in the X-axis direction relative to the magnetic field sensors 20-1 and 20-2, the partial annular yoke 30-1 and 30-2, the bias magnet 40-1, and the bias magnet 40-2. Here, the magnet 10 is magnetized in the +Z direction. In contrast, the bias magnet 40-1 and the bias magnet 40-2 are both magnetized in, for example, the -Z direction. In addition, in the Z-axis direction, the distance between the magnet 10 and the extension portion 33 of the first unit U1 is preferably equal to the distance between the magnet 10 and the extension portion 33 of the second unit U2.

[0048] [Function and effect of position detection device 3] In the position detection device 3, the position of the magnet 10 in the X-axis direction is specified based on both the output signal from the magnetic field sensor 20-1 in the first unit U1 and the output signal from the magnetic field sensor 20-2 in the second unit U2. In FIG. 10, the curve L1 represents the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20-1, and the curve L2 represents the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20-2. The characteristic diagram in FIG. 10 represents the result of a simulation using a computer. The conditions of the simulation in FIG. 10 are the same as those of the simulation in FIG. 7B. As shown in FIG. 10, the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20-1 shows a minimum value when the magnet 10 is at position -S1, increases almost linearly from position -S1 to position +S1, and shows a maximum value at position +S1. On the other hand, the magnetic field strength in the +Z direction reaching the magnetic field sensor 20-2 shows a maximum value when the magnet 10-2 is at position -S1, decreases almost linearly from position -S1 to position +S1, and shows a minimum value at position +S1. Thus, the change in the magnetic field strength in the +Z direction reaching the magnetic field sensor 20-1 accompanying the movement of the magnet 10 in the X-axis direction and the change in the magnetic field strength in the +X direction reaching the magnetic field sensor 20-2 accompanying the movement of the magnet 10 in the X-axis direction show opposite behaviors. Therefore, in the position detection device 3, by taking the difference between the output signal based on the resistance value of the magnetic field sensor 20-1 and the output signal based on the resistance value of the magnetic field sensor 20-2, even when an unnecessary magnetic field (noise magnetic field) from the outside is applied to the position detection device 3, the influence of such a noise magnetic field can be canceled.

[0049] <4. Fourth embodiment> [Configuration of position detection device 4] Next, a configuration of a position detection device 4 according to a fourth embodiment of the present disclosure will be described with reference to FIGS. 11A and 11B.

[0050] FIG. 11A is a cross-sectional view showing an example of the overall configuration of the position detector 4, and corresponds to FIG. 1B showing the position detector 1 of the first embodiment. FIG. 11B is a characteristic diagram showing an example of the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction reaching the magnetic field sensor 20 in the position detector 4, and corresponds to FIG. 2 showing the characteristic diagram of the position detector 1 of the first embodiment. The characteristic diagram of FIG. 11B shows the result of a simulation using a computer. The conditions of the simulation of FIG. 11B are basically the same as those of the simulation of FIG. 2. However, the simulation conditions are different from those of FIG. 2 in the following respects. The distance in the Z-axis direction between the facing portion 37 and the facing portion 38 of the partial annular yoke 30B is 3 mm. The dimensions of each of the facing portions 37 and 38 in the X-axis direction are 2 mm. The dimensions of each of the facing portions 37 and 38 in the Y-axis direction are 5 mm.

[0051] The position detector 4 includes a magnet 10, magnetic field sensors 20A and 20B, a partial annular yoke 30C, and a bias magnet 40. The partial annular yoke 30C has, for example, a notch 30K1 at an end on the +X side in the X-axis direction and a notch 30K2 at an end on the -X side in the X-axis direction. The magnetic field sensor 20A is provided in the notch 30K1, and the magnetic field sensor 20B is provided in the notch 30K2.

[0052] The partial annular yoke 30C has a pair of facing parts 31, 32, a pair of extending parts 33, 36, and a pair of facing parts 37, 38. In the partial annular yoke 30C, the pair of facing parts 31, 32 face each other across the magnetic field sensor 20A in the Z-axis direction, and the pair of facing parts 37, 38 face each other across the magnetic field sensor 20B in the Z-axis direction. The extending part 36 extends in the X-axis direction while facing the extending part 33 in the Z-axis direction. The extending part 36 is located on the opposite side of the magnet 10 in the Z-axis direction as viewed from the extending part 33.

[0053] The bias magnet 40 is provided in the space 30V so as to be sandwiched between the extension portion 33 and the extension portion 36 in the Z-axis direction. The bias magnet 40 is provided, for example, at a middle position in the X-axis direction of the partial annular yoke 30C. The bias magnet 40 is magnetized, for example, in the -Z direction along the Z-axis direction.

[0054] 11A, in the position detection device 4, a magnetic field line ML1 is formed that passes through the bias magnet 40, a part of the extension portion 33, the facing portion 32, the magnetic field sensor 20A, the facing portion 31, and a part of the extension portion 36. In the position detection device 4, a magnetic field line ML2 is further formed that passes through the bias magnet 40, a part of the extension portion 33, the facing portion 38, the magnetic field sensor 20B, the facing portion 37, and a part of the extension portion 36.

[0055] [Effects of the position detection device 4] In the position detection device 4, the position of the magnet 10 in the X-axis direction is specified based on both the output signal from the magnetic field sensor 20A and the output signal from the magnetic field sensor 20B. In FIG. 9B, the curve L1 represents the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20A, and the curve L2 represents the relationship between the position of the magnet 10 in the X-axis direction and the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20B. As shown in FIG. 11B, the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20A shows a minimum value when the magnet 10 is at position -S2, increases monotonically from position -S2 to position +S1, and shows a maximum value at position +S1. In contrast, the magnetic field strength in the +Z direction that reaches the magnetic field sensor 20B shows a maximum value when the magnet 10 is at position -S1, decreases almost monotonically from position -S1 to position +S2, and shows a minimum value at position +S2. In this way, the change in the magnetic field strength in the +Z direction to the magnetic field sensor 20A accompanying the movement of the magnet 10 in the X-axis direction exhibits opposite behavior to the change in the magnetic field strength in the +Z direction to the magnetic field sensor 20B accompanying the movement of the magnet 10 in the X-axis direction. Therefore, in the position detection device 3, by taking the difference between the output signal based on the resistance value of the magnetic field sensor 20A and the output signal based on the resistance value of the magnetic field sensor 20B, even when an unnecessary magnetic field (noise magnetic field) from the outside is applied to the position detection device 3, the influence of such a noise magnetic field can be canceled.

[0056] <5. Fifth embodiment> [Configuration of position detection device assembly] Next, a configuration of a position detection device assembly 50 according to a fifth embodiment of the present disclosure will be described with reference to FIG.

[0057] Fig. 12 is a schematic diagram showing an example of the overall configuration of the position detection device assembly 50. Note that the position detection device assembly 50 shown in Fig. 12 is merely an example, and in this embodiment, the components constituting the position detection device assembly 50 and their dimensions, shapes, and arrangement positions are not limited to those shown in Fig. 12.

[0058] 12, a position detection device assembly 50 includes the position detection device 1 described in the first embodiment above, and a housing 51 that houses the position detection device 1. Note that, instead of the position detection device 1, it is also possible to use, for example, the position detection devices 2 to 4 described in the second to fourth embodiments above, the position detection devices 1A and 1B which are the first and second modified examples of the first embodiment, or the position detection device 2A which is the first modified example of the second embodiment.

[0059] The housing 51 has, for example, a housing section 52, a connector section 53, and a cavity section 54. The housing section 52 is a section of the housing 51 that houses the magnetic field sensor 20 and the partial annular yoke 30. The connector section 53 has a wiring 53A connected to the magnetic field sensor 20, a terminal 53B provided at the tip of the wiring 53A, and a connection section 53C where the terminal 53B is exposed. The connector section 53 is connected to a connector of an external device to transmit and receive signals to and from the external device. The cavity section 54 is a section that houses the magnet 10 so as to be reversibly movable along the X-axis direction, and extends in the X-axis direction. In the position detection device assembly 50, the magnet 10 is held by a holding member 55, and the magnet 10 and the holding member 55 are integrally reversibly movable along the X-axis direction. Holding member 55 has holding portion 55A that holds magnet 10, and connecting portion 55B that is connected to a target object for position detection whose position in the X-axis direction, etc. is detected by position detection device 1. Therefore, according to position detection device assembly 50, by fixing housing 51 to an object (for convenience, referred to as a reference object) different from the target object for position detection, it is possible to detect the position and amount of movement of the target object for position detection relative to the reference object.

[0060] <6. Sixth embodiment> [Configuration of imaging device 100] Next, a configuration of an imaging device 100 according to a sixth embodiment of the present disclosure will be described with reference to FIG. 13A.

[0061] Fig. 13A is a perspective view showing an example of the overall configuration of the imaging device 100. Note that the imaging device 100 shown in Fig. 13A is merely an example, and in this embodiment, the components constituting the imaging device 100 and their dimensions, shapes, and arrangement positions are not limited to those shown in Fig. 13A.

[0062] The imaging device 100 constitutes, for example, a part of a camera for a smartphone equipped with an autofocus mechanism. The imaging device 100 includes, for example, an image sensor 200 that acquires an image using a CMOS or the like, and a lens module 300 that guides light from a subject to the image sensor 200.

[0063] [Configuration of lens module 300] The lens module 300 includes the position detection device 1 described in the first embodiment, a lens 305, a housing 306, a base 307, a driving unit 308, and a holding member 314. The position detection device 1 is a magnetic position detection device, and is a mechanism for detecting the position of the lens 305 when automatically focusing incident light so that light incident from a subject (hereinafter simply referred to as incident light) is imaged on the imaging surface of the image sensor 200. The driving unit 308 is an actuator that generates a driving force to move the lens 305 to focus the incident light, for example. The housing 306 is adapted to house and protect the position detection device 1 and the like. In the imaging device 100 of FIG. 13A, the position detection device 1 is provided in a position in which the magnet 10 reversibly moves along the x-axis direction. In imaging device 100 in FIG. 13A, under the control of control unit 310, drive unit 308 moves magnet 10 and lens 305 in the x-axis direction and detects the positions of magnet 10 and lens 305 in the x-axis direction.

[0064] Lens 305 is disposed above base 307 in such a position that the direction of its optical axis coincides with the x-axis. Base 307 also has an opening that passes light that has passed through lens 305. Lens module 300 and image sensor 200 are aligned so that light from a subject that has passed through lens 305 and the opening of base 307 in that order is incident on image sensor 200.

[0065] The holding member 314 is a member that holds the magnet 10 of the position detection device 1 and the lens 305 together. The holding member 314 has, for example, a cylindrical shape configured so that the lens 305 can be attached therein. The holding member 314 is provided so as to be reversibly movable along the optical axis direction of the lens 305, i.e., the x-axis direction, relative to the base 307. The base 307 supports the holding member 314 via biasing members such as a plurality of springs so that the holding member 314 can move in the x-axis direction relative to the base 307.

[0066] [Operation of the imaging device 100] The operation of the imaging device 100 is controlled by a control unit 310 provided outside the imaging device 100. The control unit 310 has a circuit configured with, for example, a CPU (Central Processing Unit) which is an arithmetic processing device, a ROM (Read Only Memory) which is a storage element for storing programs and arithmetic parameters used by the CPU, and a RAM (Random Access Memory) which is a storage element for temporarily storing parameters that change appropriately during execution of the CPU.

[0067] The autofocus mechanism is configured to detect a state in which a subject is in focus by, for example, the image sensor 200 or an autofocus sensor. The control unit 310 changes the relative position of the lens 305 with respect to the substrate 7 along the x-axis by the driving force of the driving unit 308 so that the subject is in focus. Specifically, this allows automatic focusing on the subject.

[0068] [Functions and Effects of the Imaging Device 100] Since the imaging device 100 includes the position detection device 1 of the first embodiment, it is possible to detect the position (amount of displacement) of the magnet 10 that moves integrally with the lens 305 while reducing the overall dimensions of the imaging device 100. Therefore, the imaging device 100 can perform good focusing while being compact.

[0069] <7. Seventh embodiment> [Configuration of imaging device 100A] Next, a configuration of an imaging device 100A according to a seventh embodiment of the present disclosure will be described with reference to FIG. 13B.

[0070] FIG. 13B is a schematic perspective view showing an example of the overall configuration of an imaging device 100A according to a seventh embodiment of the present disclosure. The present disclosure may include an optical image stabilization mechanism, as in the imaging device 100A. The imaging device 100A has two position detection devices 1-1 and 1-2 instead of the position detection device 1. The position detection devices 1-1 and 1-2 each have substantially the same configuration as the position detection device 1 described in the first embodiment. However, the position detection device 1-1 is provided so that the magnet 10 moves in the y-axis direction together with the lens 305, and detects the positions of the magnet 10 and the lens 305 in the y-axis direction. The position detection device 1-2 is provided so that the magnet 10 moves in the z-axis direction together with the lens 305, and detects the positions of the magnet 10 and the lens 305 in the z-axis direction. The configuration of the imaging device 100A shown in FIG. 11B is substantially the same as the configuration of the imaging device 100 shown in FIG. 13A, except that the imaging device 100A is provided with an optical image stabilization mechanism instead of an autofocus mechanism.

[0071] The optical image stabilization mechanism is configured to detect camera shake by, for example, a gyro sensor. The gyro sensor or other sensor may be provided outside the imaging device 100A. When the optical image stabilization mechanism detects camera shake, the control unit 310 controls the driving unit 308 so that the relative position of the lens 305 with respect to the base body 307 changes according to the state of the camera shake. In the driving unit 308, the lens 305 moves, for example, in the y-axis direction or the z-axis direction perpendicular to the direction of the optical axis of the lens 305, in response to a command from the control unit 310. At that time, the magnet 10 of the position detection device 1-1 and the magnet 10 of the position detection device 1-2 move together with the lens 305, so that the position of the lens 305 is detected by the magnetic field sensor 20 of the position detection device 1-1 and the magnetic field sensor 20 of the position detection device 1-2. This makes it possible to stabilize the absolute position of the lens 305 and reduce the effect of camera shake. The relative position of lens 305 with respect to base body 307 changes in a direction parallel to the y-axis or in a direction parallel to the z-axis depending on the type of camera shake.

[0072] [Functions and Effects of Imaging Device 100A] Since the imaging device 100A is provided with position detection devices 1-1 and 1-2 having substantially the same configuration as the position detection device 1 of the first embodiment, it is possible to reduce the overall dimensions of the imaging device 100A while detecting the position (amount of displacement) of the magnet 10 that moves integrally with the lens 305. Therefore, the imaging device 100A can perform good optical image stabilization while being compact.

[0073] The imaging device 100A may also include an autofocus mechanism of the imaging device 100. In this case, the imaging device 100A can perform highly accurate optical image stabilization and highly accurate focusing.

[0074] <8. Other Modifications> Although the present disclosure has been described above with reference to several embodiments, the present disclosure is not limited to the aforementioned several embodiments and various modifications are possible. For example, the magnet 10 of the position detector 4 described in the fourth embodiment may further include a back yoke 11.

[0075] In the above embodiment, the magnet 10 having a substantially rectangular parallelepiped appearance is described as an example of the magnetic field generating unit, but the present disclosure is not limited thereto. The magnetic field generating unit of the present disclosure may be, for example, the magnet 60 used in the position detection device 5 shown in FIG. 14. The magnet 60 is, for example, a ring-shaped magnet having a central axis J60 extending in the X-axis direction, and is magnetized in its radial direction. The magnet 60 faces the extension portion 33 of the partial annular yoke 30 in the Z-axis direction. Here, the magnet 60 facing the extension portion 33 in the Z-axis direction means that at least a part of the magnet 60 overlaps with the extension portion 33 in the Z-axis direction. However, it is preferable that the central axis J60 is located at a position where it overlaps with a part of the extension portion 33 in the Z-axis direction. In other words, it is preferable that more than half of the magnet 60 overlaps with a part of the extension portion 33 in the Z-axis direction. In particular, as shown in FIG. 12, the magnet 60 is preferably located directly below the extension portion 33 in the Z-axis direction. That is, in the Y-axis direction, the position of the central axis J60 of the magnet 60 may coincide with the central position 33PY of the extension portion 33 in the Y-axis direction.

[0076] Furthermore, the dimensions of each component and the layout of each component are merely examples and are not intended to be limiting.

[0077] Furthermore, the position detection device of the present disclosure is not limited to a device for detecting the position of a lens, but may be a device for detecting the spatial position of an object other than a lens. [Explanation of symbols]

[0078] 1 to 5...position detection device, 10...magnet, 11...back yoke, 20...magnetic field sensor, 30...partial annular yoke, 30K...notch, 31, 32...facing portion, 33, 36...extension portion, 34, 35...connecting portion, 40...bias magnet, 50...position detection device assembly, ML...magnetic field line.

Claims

1. a yoke having an extension portion extending in a first axial direction; a first magnetic field generating unit that is magnetized in a second axis direction intersecting the first axis direction and generates a first magnetic field; a bias magnetic field generating unit that generates a bias magnetic field and is provided on the opposite side of the first magnetic field generating unit from the extending portion of the yoke in the second axial direction; Magnetic field detection unit and Equipped with the first magnetic field generating unit is movable in the first axial direction relative to the yoke, the bias magnetic field generating unit, and the magnetic field detecting unit; The magnetic field detection unit detects a strength of the first magnetic field in a first direction. Position detection device.

2. the yoke has a shape curved along a first plane including the first axis direction and the second axis direction, The first magnetic field generating unit is disposed on the opposite side of the space surrounded by the yoke as viewed from the extending portion.

2. The position detection device according to claim 1.

3. the yoke is a partial annular yoke having a first yoke portion and a second yoke portion that are portions of an annular object that rotates along a first plane that includes the first axial direction and the second axial direction, The bias magnetic field generating unit is disposed between the first yoke portion and the second yoke portion along the direction in which the partial annular yoke rotates.

2. The position detection device according to claim 1.

4. The bias magnetic field generating unit is magnetized along the circumferential direction of the yoke.

4. The position detection device according to claim 3.

5. The yoke further includes a pair of opposing portions that face each other across the magnetic field detection unit.

2. The position detection device according to claim 1.

6. The first magnetic field generating unit is movable in the first axial direction within a range facing the extension portion in the second axial direction.

2. The position detection device according to claim 1.

7. The magnetic field detection unit is provided on the opposite side to the first magnetic field generation unit as viewed from the extending portion of the yoke in the second axial direction.

2. The position detection device according to claim 1.

8. The first orientation is parallel to a first plane that includes the first axis direction and the second axis direction.

2. The position detection device according to claim 1.

9. a first yoke having a first extending portion extending in a first axial direction; a first magnetic field generating unit that is magnetized in a second axis direction intersecting the first axis direction and generates a first magnetic field; a first bias magnetic field generating unit that is provided on the opposite side of the first magnetic field generating unit from the first extension portion of the first yoke in the second axial direction and generates a first bias magnetic field; A first magnetic field detection unit; a second yoke provided on an opposite side of the first extension portion of the first yoke from the first magnetic field generating unit in the second axial direction, the second yoke having a second extension portion extending in the first axial direction; a second bias magnetic field generating unit that is provided on the opposite side of the first magnetic field generating unit from the second extension portion of the second yoke in the second axial direction and generates a second bias magnetic field; A second magnetic field detection unit; Equipped with the first magnetic field generating unit is movable in the first axial direction relative to the first yoke, the first bias magnetic field generating unit, the first magnetic field detecting unit, the second yoke, the second bias magnetic field generating unit, and the second magnetic field detecting unit; Each of the first magnetic field detection unit and the second magnetic field detection unit detects the intensity of the first magnetic field in a first direction. Position detection device.

10. A position detection device; Lens and having The position detection device is a yoke having an extension portion extending in a first axial direction; a first magnetic field generating unit that is magnetized in a second axis direction intersecting the first axis direction and generates a first magnetic field; a bias magnetic field generating unit that generates a bias magnetic field and is provided on the opposite side of the first magnetic field generating unit from the extending portion of the yoke in the second axial direction; Magnetic field detection unit and Equipped with the first magnetic field generating unit is movable in the first axial direction relative to the yoke, the bias magnetic field generating unit, and the magnetic field detecting unit; The magnetic field detection unit detects a strength of the first magnetic field in a first direction. Lens module.

11. An imaging element; Lens module and Equipped with The lens module includes: A position detection device; Lens and having The position detection device is a yoke having an extension portion extending in a first axial direction; a first magnetic field generating unit that is magnetized in a second axis direction intersecting the first axis direction and generates a first magnetic field; a bias magnetic field generating unit that generates a bias magnetic field and is provided on the opposite side of the first magnetic field generating unit from the extending portion of the yoke in the second axial direction; Magnetic field detection unit and Equipped with the first magnetic field generating unit is movable in the first axial direction relative to the yoke, the bias magnetic field generating unit, and the magnetic field detecting unit; The magnetic field detection unit detects a change in intensity of the first magnetic field in a first direction. Imaging device.

12. a drive unit that generates a drive force to move the lens in the first axial direction; A control unit that controls the operation of the drive unit; Further equipped with The lens has an optical axis along the first axis direction, The control unit generates the driving force in the driving unit to move the lens along the optical axis direction, thereby performing focusing on the subject. The imaging device according to claim 11.

13. a driving unit that generates a driving force to move the lens in a second axis direction intersecting the first axis direction; A control unit that controls the operation of the drive unit; Further equipped with The lens has an optical axis along the first axis direction, The control unit generates the driving force in the driving unit to move the lens along the second axis, thereby performing focusing on the subject. The imaging device according to claim 11.

Images