JP6591811B2 - Optical unit driving device and camera module - Google Patents

Description

  The present invention relates to an optical unit driving device and a camera module including the same, and more particularly to a camera module including an autofocus function mounted on an electronic device such as a mobile phone.

  In recent mobile phones, a model in which a camera module is incorporated in the inside of a mobile phone casing has become the majority. Most camera modules mounted on electronic devices such as mobile phones have recently been equipped with an auto focus (AF) function. Compared to a digital camera, a camera module mounted on a mobile phone is strongly required to be miniaturized in order to be incorporated in a small casing.

  The AF function in such a camera module is generally realized by driving a lens in the optical axis direction by a lens driving device (optical unit driving device). In addition, as the lens driving device, there are a device using a stepping motor, a device using a piezoelectric element, a device using a voice coil motor (VCM), and various lens driving devices are on the market. .

  As described above, in a situation where a camera module having an AF function is naturally mounted on a mobile phone, a higher-speed AF function is required. Therefore, attention is paid to feedback control of AF function (also referred to as feedback control, closed-loop control, or servo control).

  For example, Patent Document 1 discloses an electromagnetic lens driving device having a three-axis closed loop feedback control unit. The lens driving device disclosed in Patent Document 1 has an AF function that drives a lens in the optical axis direction (Z-axis direction) and an optical type that drives the lens in directions perpendicular to the optical axis (X-axis direction and Y-axis direction). A camera shake correction (OIS: Optical Image Stabilizer) function. Then, using a hall element for AF as a position detection sensor, the driving of the lens in the optical axis direction is closed-loop feedback controlled based on the position in the direction of the three axes (X axis, Y axis, Z axis).

  For example, Patent Document 2 discloses a lens driving device in which an OIS coil, which is a planar coil (a short coil), is divided into two parts for feedback control of the OIS function. According to the configuration disclosed in Patent Document 2, the OIS Hall element is arranged between the loops of the OIS coil divided into two parts, and this causes an adverse effect caused by the magnetic field generated by the current flowing through the OIS coil. It is described that it can be avoided.

JP 2014-219675 A (published November 20, 2014) JP 2013-24938 A (released on Feb. 04, 2013)

  However, in the lens driving device disclosed in Patent Document 1, the influence (noise component) of the magnetic field generated by the current flowing through the AF coil on the output of the Hall element for AF is not considered. For this reason, there arises a problem that the gain margin of the AF control circuit for controlling the AF drive unit is small in a frequency band higher than the primary resonance frequency of the AF drive unit (AF coil and permanent magnet). In particular, when there is resonance other than the AF drive unit (for example, resonance of the support unit) in a frequency band higher than the cutoff frequency of the AF control circuit, the gain margin of the AF control circuit is impaired, and the AF drive unit There is also a problem that the feedback control is oscillated.

  There are the following two methods for increasing the gain margin of the AF control circuit in order to prevent oscillation. One is a method of adjusting the gain of the AF control circuit so as to reduce the overall gain. The other is a method of mechanically varying the resonance frequency of the resonance other than the AF drive unit so as not to impair the gain margin of the AF control circuit. However, it is not preferable to reduce the gain of the AF control circuit as a whole because it lowers the effect of feedback control of the AF function and affects the AF function. Similarly, it is not preferable to mechanically change the resonance frequency of resonance other than the AF drive unit because it affects the AF function.

  In the lens driving device disclosed in Patent Document 2, the influence (noise component) of the magnetic field generated by the current flowing in the OIS coil on the output of the OIS Hall element is considered. However, this cannot be applied to the AF function for the following reason.

  In Patent Document 2, the OIS coil is divided so as to be separated in the longitudinal direction of the opposing permanent magnet pieces. In general, a planar coil is used as the OIS coil because of the configuration of the magnetic circuit, but a planar coil is not used as the AF coil. For this reason, the AF coil cannot be divided so as to be separated in the longitudinal direction of the opposing permanent magnet pieces.

  Furthermore, in Patent Document 2, the anti-resonance between the magnetic field generated by the permanent magnet piece detected by the OIS Hall element and the magnetic field generated by the current flowing in the OIS coil detected by the OIS Hall element is eliminated. Yes. For this reason, although the influence of the magnetic field generated by the current flowing through the OIS coil is taken into account, the gain margin of the OIS control circuit that controls the OIS drive section is impaired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a lens driving device and a camera module that can more stably realize autofocus of an imaging lens.

In order to solve the above problems, an optical unit driving apparatus according to an aspect of the present invention includes an optical unit having an imaging lens, a support that supports the optical unit, and the optical unit with respect to the support. A first permanent magnet and a first coil for displacing in the optical axis direction of the imaging lens, a magnetic displacement detecting unit for detecting displacement of the optical unit in the optical axis direction, and the light of the optical unit And a permanent magnet for detection that is displaced relative to the magnetic displacement detector in accordance with an axial displacement, wherein the permanent magnet for detection is detected by the magnetic displacement detector. A first component that is a magnetic field generated by the magnetic displacement detector and a second component that is a magnetic field generated by a current flowing through the first coil detected by the magnetic displacement detector is when a direct current is passed through the first coil. same phase der in is, with the first component The second component has a magnetic anti-resonance frequency when an alternating current is passed through the first coil. At the magnetic anti-resonance frequency, the output of the magnetic displacement detector and the first the phase difference between the current flowing in the coil is characterized that you transition 180 °.

  According to one aspect of the present invention, the first component and the second component are in phase when a direct current is passed through the first coil. For this reason, the first component and the second component have the same phase in a frequency band lower than the primary resonance frequency of the first permanent magnet and the first coil. In the frequency band higher than the primary resonance frequency of the first permanent magnet and the first coil, the first component and the second component are in opposite phases and have a magnetic anti-resonance frequency. Furthermore, the output of the magnetic displacement detector is mainly the sum of the first component and the second component.

  For this reason, in the frequency band around the anti-resonance frequency (region II in FIG. 9), the first component and the second component have a phase opposite to that when a direct current is passed through the first coil. Thus, the gain of the output of the magnetic displacement detector in the above configuration is small. As a result, the gain margin of the control circuit in the frequency band higher than the control frequency of the control circuit (AF control circuit) that controls the current flowing through the first coil can be increased based on the output of the magnetic displacement detector.

  Since the gain margin of the control circuit is large, the control circuit is less likely to oscillate even when resonance other than the resonance between the first coil and the first permanent magnet exists. Thus, according to the above aspect, the optical section of the optical unit can be obtained without reducing the resonance frequency of the resonance other than the resonance between the first coil and the first permanent magnet without reducing the gain of the control circuit. The displacement (autofocus) in the optical axis direction can be feedback controlled more stably.

1 is a perspective view illustrating a schematic configuration of a camera module 100 according to Embodiment 1. FIG. FIG. 2 is a schematic configuration view of the camera module 100 shown in FIG. FIG. 2 is a schematic sectional view of the camera module 100 shown in FIG. FIG. 3 schematically shows a magnetic circuit of the camera module 100 shown in FIG. 1, and is an enlarged view of a box C in FIG. The frequency characteristics of the output of the AF Hall element 6 in the magnetic circuit shown in FIG. 4 are schematically shown. 5 schematically shows another magnetic circuit which is a contrast example of the magnetic circuit shown in FIG. The frequency characteristics of the output of the AF Hall element 6 in the magnetic circuit shown in FIG. 6 are schematically shown. 1 schematically shows the frequency characteristics of vibration in the optical axis direction of the AF movable part in the camera module 100 shown in FIG. The frequency characteristics shown in FIGS. 5, 7, and 8 are shown. FIG. 3 is a schematic cross-sectional view taken along the line AA, showing a schematic configuration of a camera module 200 according to Embodiment 2. FIG. 5 is a schematic cross-sectional view taken along the line AA, illustrating a schematic configuration of a camera module 300 according to Embodiment 3. FIG. 5 is a schematic cross-sectional view taken along the line AA, showing a schematic configuration of a camera module 400 according to Embodiment 4. It is a schematic configuration of the camera module 400 shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail.

Embodiment 1
Embodiment 1 of the present invention will be described below with reference to FIGS.

  FIG. 1 is a perspective view illustrating a schematic configuration of a camera module 100 according to the first embodiment.

  2 shows a schematic configuration of the camera module 100 shown in FIG. 1, and is a cross-sectional view taken along the line AA.

  3 shows a schematic configuration of the camera module 100 shown in FIG. 1, and is a cross-sectional view taken along line BB.

  As shown in FIG. 1, the camera module 100 has an auto focus (AF) function, and includes an optical unit driving device 1, a support 10, an optical unit 20, an imaging unit 30, an infrared blocking filter 34, and an opening 41. The formed cover 40 and a wiring board (not shown) are provided. The wiring substrate (not shown) is a wiring substrate for electrically connecting the optical unit driving device 1 and the imaging unit 30 to the outside, and may be a flexible substrate, and is not particularly limited. Omitted.

  Hereinafter, the direction on the optical unit driving apparatus 1 side with respect to the imaging unit 30 is set to the upper side (+ z), and the direction on the imaging unit 30 side with respect to the optical unit driving apparatus 1 is set to the lower side (−z). Similarly, in FIG. 3, the orientations of the camera module 100 on the upper side, lower side, left side, and right side are front (+ x), rear (−x), left (+ y), and right (−y), respectively. To do. Also, the direction connecting the upper side and the lower side is the vertical direction (z-axis direction) (optical axis direction), and the direction connecting the left side and right side is the left-right direction (y-axis direction) (first direction perpendicular to the optical axis, A direction connecting the front and the rear in the second direction and the third direction is a front-rear direction (x-axis direction). Further, in order to facilitate understanding, an xyz orthogonal coordinate system is added to the drawing.

  This is for the convenience of explanation, and does not define the vertical and horizontal directions when the camera module 100 is manufactured and used. For example, it may be used so that the optical unit driving device 1 is on the lower side and the imaging unit 30 is on the upper side. Further, for example, the optical unit driving apparatus 1 may be controlled using a coordinate system that is not an orthogonal coordinate system.

  As shown in FIG. 2, the optical unit driving apparatus 1 includes a driving permanent magnet 2 (first permanent magnet), an AF coil 3 (first coil), a detection permanent magnet 5, and an AF Hall element 6 (magnetically). Displacement detector), electric circuit unit 7, support 10, upper leaf spring 11, lower leaf spring 12, lens holder 23, and base member 33.

  The optical unit 20 is an imaging optical unit that connects an image of a subject to the imaging unit 30. As shown in FIG. 2, the optical unit 20 includes a plurality of imaging lenses 21 and a lens barrel 22 having a cylindrical shape. The plurality of imaging lenses 21 are stored inside the lens barrel 22 so that the optical axes thereof coincide with the axis of the lens barrel 22. Note that the imaging lens 21 and the lens barrel 22 are fixed with an adhesive so as not to shift. Further, the center of gravity of the optical unit 20 may be on the optical axis of the optical unit 20 so that the driving of the optical unit driving device 1 is mechanically stabilized.

  As shown in FIG. 2, the imaging unit 30 includes an imaging element 31 and a substrate 32 perpendicular to the optical axis. Further, the optical unit driving device 1 and the optical unit 20 are placed on the imaging unit 30. The imaging element 31 is placed on the substrate 32 and receives light that has passed through the opening 41, the plurality of imaging lenses 21, and the infrared blocking filter 34. As described above, the imaging unit 30 is a normal solid-state imaging device having an imaging function, and is not particularly limited.

  The infrared blocking filter 34 is a lid (lid) glass that has an infrared blocking function and closes the opening of the base member 33 as shown in FIG. The infrared blocking filter 34 plays a role of a sensor cover that covers the image sensor 31 together with the base member 33. The infrared blocking filter 34 may be provided as a separate member from the lid glass.

  The cover 40 is an exterior covering the optical unit driving device 1. The cover 40 has an opening 41 through which light enters the optical unit 20, and restricts deformation of the upper leaf spring 11. Due to the deformation limitation, the cover 40 prevents the upper leaf spring 11 and the lower leaf spring 12 from breaking, and prevents the optical unit 20 from falling off the camera module 100.

(AF fixed part and AF movable part)
The configuration of the optical unit driving device 1 includes an AF fixing unit that is fixed so as not to swing in the optical axis direction with respect to the imaging unit 30, an AF movable unit that can swing in the optical axis direction with respect to the imaging unit 30, and an AF. The fixed portion and the AF movable portion can be divided into AF connecting portions that are slidably connected.

  In the first embodiment, as shown in FIG. 2, the driving permanent magnet 2, the AF hall element 6, the electric circuit unit 7, and the support 10 are included in the AF fixing unit. The AF coil 3, the detection permanent magnet 5, and the lens holder 23 are included in the AF movable part. Further, the upper leaf spring 11 and the lower leaf spring 12 are included in the AF connection portion. Contrary to the first embodiment, the driving permanent magnet 2 may be included in the AF movable portion, and the AF coil 3 may be included in the AF fixed portion. Similarly, the AF hall element 6 and the electric circuit section 7 may be included in the AF movable section, and the detection permanent magnet 5 may be included in the AF fixed section.

(Configuration of optical unit driving device)
Below, the structure of the optical part drive device 1 is demonstrated based on FIG. 2 and FIG.

  The driving permanent magnet 2 is four magnet pieces arranged one by one on the front, back, left and right of the optical unit 20, and is fixed to the support 10. Further, the driving permanent magnet 2 is arranged so that the N pole faces the AF coil 3 and the S pole faces the support 10.

  The AF coil 3 is wound around the outer peripheral side surface of the lens holder 23 engaged with the optical unit 20 so that the winding axis coincides with the optical axis. For this reason, the arrangement of the AF coil 3 is fixed with respect to the optical unit 20 and is separated from the support 10.

  The driving permanent magnet 2 and the AF coil 3 facing each other are an AF driving unit, and generate a thrust force that displaces the optical unit 20 in the optical axis direction (vertical direction, z-axis direction). For example, when a counterclockwise current is applied to the AF coil 3 as viewed from above, an upward Lorentz force is generated in the AF coil 3. Then, using this Lorentz force as a thrust, the optical unit driving apparatus 1 displaces the optical unit 20 together with the lens holder 23.

  The detection permanent magnet 5 is displaced relative to the AF hall element 6 in accordance with the displacement of the optical section 20 in order to assist the detection of the displacement of the optical section 20 by the AF hall element 6. Further, it is arranged so as to face the AF hall element 6. The detection permanent magnet 5 detects a magnetic field (magnetic field) generated by the current flowing in the AF coil 3 detected by the AF hall element 6 (hereinafter referred to as a magnetic field of the AF coil 3) and the AF hall element 6. It arrange | positions so that the magnetic field (Hereinafter, the magnetic field of the permanent magnet 5 for a detection) which the permanent magnet 5 for a detection has an antiresonance point (antiresonance frequency). For this reason, the detection permanent magnet 5 is arranged below the AF coil 3 so that the north pole faces upward and the south pole faces downward. Further, the permanent magnet 5 for detection is fixed to the lens holder 23 so as to be disposed near the center of the left outer peripheral side surface of the lens holder 23 when viewed from the optical axis direction. In other words, the detection permanent magnet 5 is disposed near the center of the long side of the drive permanent magnet 2.

  The magnetic pole of the detection permanent magnet 5 in which the magnetic field of the AF coil 3 detected by the AF hall element 6 and the magnetic field of the detection permanent magnet 5 detected by the AF hall element 6 have antiresonance points. The direction of (N pole and S pole) is uniquely determined from the arrangement of the driving permanent magnet 2, the AF coil 3, and the AF hall element 6. Specifically, in the magnetic field of the AF coil 3, the component in the direction in which the AF Hall element 6 detects the magnetic flux density at the position where the AF Hall element 6 is arranged and the magnetic field of the detection permanent magnet 5 The component in the direction in which the Hall element for AF 6 detects the magnetic flux density at the position where the Hall element for AF 6 is disposed may be in phase when the current flowing through the AF coil 3 is a direct current.

  The AF hall element 6 is a magnetic displacement detection unit for detecting the displacement of the optical unit 20 in the optical axis direction based on the magnetic field of the detection permanent magnet 5, and the component of the magnetic flux density in the direction perpendicular to the optical axis. Is arranged to measure. Further, the AF hall element 6 is fixed to the support 10 via the electric circuit portion 7 so as to be arranged near the center of the side of the inner peripheral side surface on the left side of the support 10 as viewed from the optical axis direction. ing. For this reason, the hall element for AF 6 is disposed below the driving permanent magnet 2 so as to measure the component of the magnetic flux density in the left-right direction (the y-axis direction, the direction perpendicular to the optical axis). The AF Hall element 6 may be another type of magnetic displacement detector such as a magnetoresistive (MR) element.

  The electric circuit unit 7 is a flexible printed circuit board or the like for electrical connection of the AF hall element 6, and is fixed to the support 10. In addition, the electric circuit part 7 and the support body 10 can also be made into an integral member by making the support body 10 into a molded circuit component (Molded Interconnect Device, MID) in which an electric circuit is formed.

  The support 10 is a frame shaped like a rectangular box, and is fixed to the base member 33. The support 10 supports the driving permanent magnet 2 and the AF hall element 6, and supports the lens holder 23 via the upper leaf spring 11. The support 10 may be only a metal frame, or may be a metal frame having a resin holding member for holding the upper leaf spring 11 or the like, and a molded circuit component as described above. It may be.

  The support 10 is preferably a magnetic body so that the magnetic field of the driving permanent magnet 2 can efficiently generate Lorentz force in the AF coil 3. When the magnetic flux of the magnetic field of the driving permanent magnet 2 is incident on the AF coil 3 at a high magnetic flux density so as to be perpendicular to the AF coil 3 and the optical axis, a Lorentz force is efficiently generated in the AF coil 3. Accordingly, it is preferable that the support 10 forms a magnetic circuit in which the magnetic flux of the magnetic field of the driving permanent magnet 2 passes through the AF coil 3 in this way.

  The outer end portion of the upper leaf spring 11 is fixed to the upper portion of the support 10, and the inner end portion of the upper leaf spring 11 is fixed to the upper portion of the lens holder 23. And since the outer side edge part and inner side edge part of the upper side leaf | plate spring 11 are connected elastically, the upper side leaf | plate spring 11 connects the support body 10 and the lens holder 23 so that sliding is possible.

  The outer end of the lower leaf spring 12 is fixed to the base member 33, and the inner end of the lower leaf spring 12 is fixed to the lower portion of the lens holder 23. And since the outer side edge part and inner side edge part of the lower side leaf | plate spring 12 are connected elastically, the lower side leaf | plate spring 12 connects the base member 33 and the lens holder 23 so that sliding is possible.

  Thus, the upper leaf spring 11 and the lower leaf spring 12 are arranged in pairs above and below the lens holder 23 and are supported so as to surround the lens holder 23. Further, since the upper leaf spring 11 and the lower leaf spring 12 are generally used in a camera module having a normal AF function, detailed description and illustration are omitted.

  The lens holder 23 holds the lens barrel 22 inside and is displaced together with the optical unit 20 in the optical axis direction. The position where the lens holder 23 holds the lens barrel 22 is adjusted and fixed in advance using a jig or the like. The lens holder 23 is supported so as to be slidable with respect to the imaging unit 30. The lens holder 23 and the lens barrel 22 are fixed with an adhesive so as not to be displaced.

  The base member 33 is disposed below the support 10 and has a rectangular shape, and has an opening penetrating in the optical axis direction at the center of a surface perpendicular to the optical axis. The base member 33 plays a role of a sensor cover that covers the image sensor 31 together with the infrared blocking filter 34.

  An AF control circuit (not shown) for controlling the AF drive unit (the drive permanent magnet 2 and the AF coil 3) is electrically connected to the AF hall element 6 via the electrical circuit unit 7. The AF coil 3 is electrically connected via the lower leaf spring 12. Based on the output of the hall element for AF 6, the displacement of the optical unit 20 in the optical axis direction is repeatedly compared with the target value, and the AF control circuit performs feedback control of the current flowing through the AF coil 3. The AF control circuit may be formed on the substrate 32 or may be formed outside the camera module 100. Alternatively, the AF control circuit may be formed (packaged) integrally with the AF hall element 6. When the AF control circuit and the AF Hall element 6 are packaged, since the wiring of the AF Hall element 6 is completed inside the package, the wiring inside the camera module 100 can be simplified. .

(Magnetic circuit)
Hereinafter, a magnetic circuit in the camera module 100 will be described with reference to FIG.

  4 schematically shows the magnetic circuit of the camera module 100 shown in FIG. 1, and is an enlarged view of a box C in FIG.

  As shown in FIG. 4, a case where a direct current flows counterclockwise in the AF coil 3 as viewed from above and an upward Lorentz force is generated in the AF coil 3 will be considered.

  The permanent magnet 5 for detection has the north pole facing upward and the south pole facing downward. For this reason, in the magnetic field B12 of the permanent magnet for detection, the component (hereinafter, signal component) (first component) of the magnetic flux density in the left-right direction (y-axis direction) at the position where the AF hall element 6 is disposed is As the permanent magnet 5 is displaced from below to above, the permanent magnet 5 changes from leftward (+ y direction) to rightward (−y direction).

  A direct current flows counterclockwise through the AF coil 3. For this reason, in the magnetic field B22 of the AF coil, the component (hereinafter referred to as noise component) (second component) of the magnetic flux density in the left-right direction (y-axis direction) at the position where the AF hall element 6 is disposed is the detection permanent. As the magnet 5 is displaced from below to above, it changes from leftward (+ y direction) to right (−y direction). Further, the noise component also changes from the left direction (+ y direction) to the right direction (−y direction) even when the magnitude of the counterclockwise current flowing through the AF coil 3 increases.

  Therefore, when a DC current flows counterclockwise through the AF coil 3 as viewed from above, the magnetic field (signal component) of the detection permanent magnet 5 detected by the AF hall element 6 and the AF detected by the AF hall element 6 are detected. The magnetic field (noise component) of the coil 3 changes in the same direction and strengthens each other.

  The theoretical model of the vibration in the optical axis direction of the AF movable part (AF coil 3, detection permanent magnet 5, lens holder 23, etc.) of the camera module 100 is a second-order lag of one degree of freedom in control engineering. Corresponds to the system. Therefore, based on the transfer function of the theoretical model, the frequency characteristic of the signal component has a primary resonance point that is the resonance frequency of the driving permanent magnet 2 and the AF coil 3. Further, the phase of the signal component is shifted by 180 (deg.) From the phase of the current flowing through the AF coil 3 in a frequency band higher than the primary resonance point.

  Therefore, the signal component and the noise component have the same phase in the frequency band lower than the primary resonance frequency of the AF driving unit (the driving permanent magnet 2 and the AF coil 3). In the frequency band higher than the primary resonance frequency of the AF drive unit, the signal component and the noise component are in opposite phases.

  When a direct current flows clockwise through the coil 3 for AF and a downward Lorentz force is generated in the coil 3 for AF, the signal component and the noise component are similarly the primary resonance frequency. In the lower frequency band, the phase is the same, and in the frequency band higher than the primary resonance frequency, the phase is opposite. In addition, for simplification, in the above description, the magnitude of the current flowing through the AF coil 3 and the change in the magnitude are not taken into account, but the signal component and the noise component are also taken into consideration. In the frequency band lower than the primary resonance frequency, the phase is the same, and in the frequency band higher than the primary resonance frequency, the phase is opposite.

(Frequency characteristics of the hall element for AF)
The frequency characteristics of the AF hall element 6 in the camera module 100 will be described below with reference to FIG.

  FIG. 5 schematically shows the frequency characteristics of the output of the Hall element for AF 6 in the magnetic circuit shown in FIG. The lower axis of FIG. 5 indicates frequency (Hz), the left axis indicates gain (20 dB / div), and the right axis indicates phase (deg.).

  The phase characteristic 62 indicates the frequency characteristic of the phase difference between the output of the AF hall element 6 and the current flowing through the AF coil 3, and refers to the right axis and the lower axis. The gain characteristic 72 indicates the frequency characteristic of the gain of the output of the Hall element 6 for AF, has an anti-resonance point 72a, and refers to the left axis and the lower axis.

(Magnetic circuit of the control example)
Hereinafter, another magnetic circuit as a control example will be described with reference to FIG. In the camera module 100, the direction of the magnetic poles of the detection permanent magnet 5 is reversed.

  FIG. 6 schematically shows another magnetic circuit that is a contrast to the magnetic circuit shown in FIG.

  As shown in FIG. 6, a case where a direct current flows counterclockwise in the AF coil 3 as viewed from above and an upward Lorentz force is generated in the AF coil 3 will be considered.

  The permanent magnet 5 for detection has the south pole facing upward and the north pole facing downward. For this reason, in the magnetic field B11 of the detection permanent magnet, the component (signal component) of the magnetic flux density in the left-right direction (y-axis direction) at the position where the AF hall element 6 is disposed is the detection permanent magnet 5 upward As it is displaced to the right, it changes from the right direction (-y direction) to the left direction (+ y direction).

  A direct current flows counterclockwise through the AF coil 3. For this reason, in the magnetic field B21 of the AF coil, the component (noise component) of the magnetic flux density in the left-right direction (y-axis direction) at the position where the AF hall element 6 is disposed is such that the detection permanent magnet 5 moves from below to above. As it is displaced, it changes from leftward (+ y direction) to right (−y direction). Further, the noise component also changes from the left direction (+ y direction) to the right direction (−y direction) even when the magnitude of the counterclockwise current flowing through the AF coil 3 increases.

  Therefore, when a DC current flows counterclockwise through the AF coil 3 as viewed from above, the magnetic field (signal component) of the detection permanent magnet 5 detected by the AF hall element 6 and the AF detected by the AF hall element 6 are detected. The magnetic field (noise component) of the coil 3 changes in the opposite direction and weakens each other.

  The theoretical model of the vibration in the optical axis direction of the AF movable part (AF coil 3, detection permanent magnet 5, lens holder 23, etc.) of the camera module 100 is a second-order lag of one degree of freedom in control engineering. Corresponds to the system. Therefore, based on the transfer function of the theoretical model, the frequency characteristic of the signal component has a primary resonance point that is the resonance frequency of the driving permanent magnet 2 and the AF coil 3. Further, the phase of the signal component is shifted by 180 (deg.) From the phase of the current flowing through the AF coil 3 in a frequency band higher than the primary resonance point.

  Therefore, in the frequency band lower than the primary resonance frequency of the AF driving unit (the driving permanent magnet 2 and the AF coil 3), the signal component and the noise component are in opposite phases. In the frequency band higher than the primary resonance frequency of the AF drive unit, the signal component and the noise component are in phase.

  When a direct current flows clockwise through the coil 3 for AF and a downward Lorentz force is generated in the coil 3 for AF, the signal component and the noise component are similarly the primary resonance frequency. In the lower frequency band, the phase is the same, and in the frequency band higher than the primary resonance frequency, the phase is opposite. In addition, for simplification, in the above description, the magnitude of the current flowing through the AF coil 3 and the change in the magnitude are not taken into account, but the signal component and the noise component are also taken into consideration. In the frequency band lower than the primary resonance frequency, the phase is the same, and in the frequency band higher than the primary resonance frequency, the phase is opposite.

(Frequency characteristics of the hall element for AF of the control example)
The frequency characteristics of the AF Hall element 6 in the control example will be described below with reference to FIG.

  FIG. 7 schematically shows the frequency characteristics of the output of the Hall element for AF 6 in the magnetic circuit shown in FIG. The lower axis of FIG. 6 indicates frequency (Hz), the left axis indicates gain (20 dB / div), and the right axis indicates phase (deg.).

  The phase characteristic 61 indicates the frequency characteristic of the phase difference between the output of the AF hall element 6 and the current flowing through the AF coil 3, and refers to the right axis and the lower axis. The gain characteristic 71 indicates the frequency characteristic of the gain of the output of the Hall element 6 for AF, does not have an antiresonance point, and refers to the left axis and the lower axis.

(Measurement of frequency characteristics of displacement of AF moving part)
FIG. 8 schematically shows frequency characteristics of vibration in the optical axis direction of the AF movable part (AF coil 3, detection permanent magnet 5, lens holder 23, etc.) in the camera module 100 shown in FIG.

  Hereinafter, a method of measuring the frequency characteristic of vibration shown in FIG. 8 will be described with reference to FIG.

  First, a measuring instrument (not shown) was installed so that the amplitude of vibration in the optical axis direction of the AF movable part could be measured. The measuring device is a non-electromagnetic measuring device, for example, a laser Doppler vibrometer. Next, an alternating current was passed through the AF coil 3 to vibrate the AF movable part. And the frequency characteristic of the vibration of the AF movable part was measured by the measuring device installed instead of the Hall element 6 for AF. As a result, the frequency characteristics of vibration of the AF movable part excluding the influence (noise component) of the magnetic field of the AF coil 3 were measured. In addition, you may measure the frequency characteristic of the vibration of AF movable part with another measuring method.

  The phase characteristic 63 indicates the frequency characteristic of the phase difference between the vibration in the optical axis direction of the AF movable part and the current passed through the AF coil 3, and refers to the right axis and the lower axis. The gain characteristic 73 indicates the frequency characteristic of the vibration gain of the AF movable part, and refers to the left axis and the lower axis.

(Frequency characteristics of signal components)
FIG. 8 shows the frequency characteristics of the vibration of the AF movable part excluding the influence (noise component) of the magnetic field of the AF coil 3. For this reason, the frequency characteristic shown in FIG. 8 shows the same characteristics as the frequency characteristic of the signal component based on the transfer function of the theoretical model.

  Hereinafter, the signal components will be described with reference to FIG. The magnetic circuits shown in FIGS. 4 and 6 are the same except for the direction of the magnetic poles of the detection permanent magnet 5. Therefore, the following description applies to the signal component in the magnetic circuit shown in FIG. 4 and the signal component in the magnetic circuit shown in FIG.

  The theoretical model of the vibration in the optical axis direction of the AF movable part of the camera module 100 corresponds to a second-order lag system with one degree of freedom in control engineering. Therefore, based on the transfer function of the theoretical model, the frequency characteristic of the signal component has a resonance point that is a primary resonance frequency between the driving permanent magnet 2 and the AF coil 3. The frequency characteristic of the signal component is that the gain is substantially constant and the phase is 0 (deg.) Or 360 (deg.) In the frequency band lower than the resonance point, and the phase is 180 ( deg.) and the gain decreases with a slope of −40 (dB / dec).

(Comparison of frequency characteristics of gain)
FIG. 9 shows the frequency characteristics (gain characteristics 71 to 73) of the gain shown in FIG. 5, FIG. 7, and FIG. In practice, the output of the AF hall element 6 includes the magnetic field (signal component) of the detection permanent magnet 5 detected by the AF hall element 6 and the magnetic field of the AF coil 3 detected by the AF hall element 6. This is a signal in which other noise overlaps with the sum of (noise component). However, for the sake of simplicity, the output of the AF Hall element 6 is considered as the sum of the signal component and the noise component.

  Region I is a frequency band in which the gain of the signal component is sufficiently larger than the gain of the noise component, and is a low frequency band. Therefore, in region I, the gain characteristic 72 of the output of the Hall element for AF 6 in the camera module 100 (magnetic circuit shown in FIG. 4) and the Hall element for AF in the control example (magnetic circuit shown in FIG. 6) The gain characteristic 71 of the output No. 6 substantially matches the gain characteristic 73 of the signal component. The resonance frequency between the driving permanent magnet 2 and the AF coil 3 is in the region I.

  Region III is a frequency band in which the gain of the noise component is sufficiently larger than the gain of the signal component, and is a high frequency band. For this reason, in the region III, the gain characteristic 72 of the output of the Hall element for AF 6 in the camera module 100 and the gain characteristic 71 of the output of the Hall element for AF 6 in the control example substantially coincide with each other. On the other hand, the gain characteristic 72 and the gain characteristic 71 are away from the gain characteristic 73 of the signal component and gradually approach a constant value. For this reason, it is estimated that the gain characteristic 72 and the gain characteristic 71 substantially coincide with the gain characteristic of the noise component.

  Region II is an intermediate frequency band between region I and region III. For this reason, the difference between the gain characteristic 72 and the gain characteristic 71 due to the phase relationship between the signal component and the noise component is significant.

  In the region II, the gain characteristic 72 of the output of the Hall element for AF 6 in the camera module 100 is such that the signal component and the noise component are in opposite phases. In region II, in the gain characteristic 71 of the output of the AF Hall element 6 in the control example, the signal component and the noise component are in phase. For this reason, in the region II, the gain characteristic 72 having the antiresonance point 72a is smaller than the gain characteristic 71 having no antiresonance point. In other words, the AF control circuit in the camera module 100 has more gain margin than the AF control circuit in the control example.

  Therefore, even if there is a resonance point (for example, twisting of the upper leaf spring 11 shown in FIG. 2) in a frequency band higher than the control frequency band of the AF control circuit, the anti-resonance point 72a. An AF control circuit that exhibits a frequency characteristic such as the gain characteristic 72 having an oscillation hardly oscillates. For this reason, the AF control circuit in the camera module 100 can feedback-control the AF drive unit more stably than the AF control circuit in the control example.

(effect)
FIG. 4 shows a case where a direct current is passed through the AF coil 3 counterclockwise so that an upward (+ z direction) Lorentz force is generated in the camera module 100. In this case, the optical unit 20 is displaced upward together with the lens holder 23 using an upward Lorentz force as a thrust. Then, according to the displacement of the optical unit 20, the magnetic field B12 of the detection permanent magnet 5 detected by the AF hall element 6 and the magnetic field B22 of the AF coil 3 detected by the AF hall element 6 are directed rightward (− It changes so that the component of (y direction) increases.

  Therefore, in the magnetic field of the permanent magnet 5 for detection, in the magnetic flux density component (signal component) in the direction perpendicular to the optical axis at the position where the AF hall element 6 is disposed and in the magnetic field of the AF coil 3, the AF hole The magnetic flux density component (noise component) in the direction perpendicular to the optical axis at the position where the element 6 is disposed is a frequency lower than the primary resonance frequency of the AF driving unit (the driving permanent magnet 2 and the AF coil 3). In the band, the phase is the same, and in the frequency band higher than the primary resonance frequency of the AF drive unit, the phase is reversed. For this reason, the signal component and the noise component have an anti-resonance peak frequency (anti-resonance point) in a frequency band higher than the primary resonance frequency of the AF drive unit.

  Therefore, as shown in FIG. 9, the camera module 100 (gain characteristic 72) has more gain margin of the AF control circuit than the control example (gain characteristic 71) having no anti-resonance point. For this reason, the AF control circuit hardly oscillates and is stable.

  As shown in FIG. 2, since the AF Hall element 6 is in the AF fixed portion, the number of wires to the AF movable portion is small. For this reason, the wiring inside the camera module 100 can be simplified. Note that simplification of the wiring inside the camera module 100 is preferable because it saves wiring work such as soldering and reduces the manufacturing cost of the camera module 100.

  Further, the detection permanent magnet 5 and the AF hall element 6 facing each other are located between the AF drive unit (the drive permanent magnet 2 and the AF coil 3) and the base member 33. In general, a wiring board (not shown) for electrically connecting the optical unit driving device 1 and the imaging unit 30 to the outside is fixed to the substrate 32. For this reason, since the wiring can be shortened, it is preferable that the AF Hall element 6 is disposed near the substrate 32.

  Further, when viewed from above, the detection permanent magnet 5 is disposed in the vicinity of the center of the outer peripheral side surface of the lens holder 23, and the AF Hall element 6 is disposed in the vicinity of the center of the inner peripheral side surface of the support 10. In the vicinity of the side center, the outer peripheral side surface of the lens holder 23 and the inner peripheral side surface of the support 10 face each other in parallel. For this reason, the permanent magnet 5 for detection and the Hall element 6 for AF can be easily arrange | positioned so as to oppose in parallel.

(Modification)
The driving permanent magnet 2 may be disposed so that the south pole faces the AF coil 3 and the north pole faces the support 10. In this case, when a clockwise current is applied to the AF coil 3 as viewed from above, an upward Lorentz force is generated in the AF coil 3. The optical unit driving apparatus 1 displaces the optical unit 20 together with the lens holder 23 using the Lorentz force as a thrust. Therefore, the detection permanent magnet 5 is arranged below the AF coil 3 so that the south pole faces upward and the north pole faces downward.

  Alternatively, the detection permanent magnet 5 may be disposed above the AF coil 3, and the AF hall element 6 may be disposed above the drive permanent magnet 2. In this case, the direction of change of the magnetic field of the AF coil 3 sensed by the AF hall element is reversed. Therefore, if the driving permanent magnet 2 is arranged so that the north pole faces the AF coil 3, the detection permanent magnet 5 is arranged so that the south pole faces upward and the north pole faces downward. The If the driving permanent magnet 2 is arranged so that the south pole faces the AF coil 3, the detection permanent magnet 5 is arranged so that the north pole faces upward and the south pole faces downward. The

[Embodiment 2]
The following describes Embodiment 2 of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 10 shows a schematic configuration of the camera module 200 according to the second embodiment, and corresponds to a cross-sectional view taken along the line AA.

  Similarly to the camera module 100 of the first embodiment, the camera module 200 has an AF function, the optical unit driving device 1, the optical unit 20, the imaging unit 30, the infrared blocking filter 34, the cover 40 in which the opening 41 is formed, and A wiring board (not shown) is provided.

  As in the first embodiment, the optical unit driving apparatus 1 includes a driving permanent magnet 2, an AF coil 3, a detection permanent magnet 5, an AF hall element 6, an electric circuit unit 7, a support 10, and an upper leaf spring 11. The lower leaf spring 12, the lens holder 23, and the base member 33 are provided. Similarly to the first embodiment, the optical unit 20 includes a plurality of imaging lenses 21 and a lens barrel 22. Similarly to the first embodiment, the imaging unit 30 includes an imaging element 31 and a substrate 32 perpendicular to the optical axis.

(AF fixed part and AF movable part)
The configuration of the optical unit driving device 1 includes an AF fixing unit that is fixed so as not to swing in the optical axis direction with respect to the imaging unit 30, an AF movable unit that can swing in the optical axis direction with respect to the imaging unit 30, and an AF. The fixed portion and the AF movable portion can be divided into AF connecting portions that are slidably connected.

  Unlike the camera module 100 of the first embodiment, in the camera module 200 of the second embodiment, the AF hall element 6 and the electric circuit unit 7 are included in the AF movable unit, and the detection permanent magnet 5 is included in the AF fixing unit. It is. Therefore, the driving permanent magnet 2, the detection permanent magnet 5, the support 10 and the substrate 32 are included in the AF fixing portion. Further, the AF coil 3, the AF Hall element 6, the electric circuit unit 7, and the lens holder 23 are included in the AF movable unit.

(Arrangement of permanent magnet for detection and hall element for AF)
The arrangement of the detection permanent magnet 5 and the AF Hall element 6 will be described below with reference to FIG.

  The detection permanent magnet 5 is fixed to the support body 10 so as to be arranged near the center of the side of the inner peripheral side surface on the left side of the support body 10 when viewed from the optical axis direction. The AF hall element 6 is fixed to the lens holder 23 via the electric circuit portion 7 so as to be arranged near the center of the side of the left outer peripheral side surface of the lens holder 23 when viewed from the optical axis direction. Yes. The driving permanent magnet 2 is arranged so that the north pole faces the AF coil 3 and the south pole faces the support 10. In addition, the detection permanent magnet 5 is disposed below the driving permanent magnet 2, and the AF hall element 6 is disposed below the AF coil 3.

  Further, the detection permanent magnet 5 is arranged so that the frequency characteristic of the output of the AF hall element 6 has an anti-resonance point. Specifically, the detection permanent magnet 5 is arranged so that the north pole faces upward and the south pole faces downward.

(effect)
Similar to the camera module 100 of the first embodiment, the camera module 200 of the second embodiment has a large gain margin of the AF control circuit. For this reason, the AF control circuit hardly oscillates and is stable.

  In the camera module 200, as shown in FIG. 10, the AF coil 3 and the AF Hall element 6 are included in the AF movable part, whereas the driving permanent magnet 2 and the detection permanent magnet 5 are It is included in the AF fixing unit. Therefore, both the driving permanent magnet 2 and the detection permanent magnet 5 are fixed to the support 10. Further, the driving permanent magnet 2 is arranged so that the S pole is further away from the AF Hall element 6 than the N pole, and the detection permanent magnet 5 is driven so that the N pole faces the driving permanent magnet 2. The permanent magnet 2 is disposed below the S pole. With this arrangement, the south pole of the drive permanent magnet 2 and the north pole of the detection permanent magnet 5 are close to each other, and a magnetic attractive force is generated between the drive permanent magnet 2 and the detection permanent magnet 5. Occurs.

  In other words, the drive permanent magnet 2 is fixed to the support 10 so that the south pole faces the support 10, and the detection permanent magnet 5 is attached to the support 10 so that the north pole faces the drive permanent magnet 2. Fixed. For this reason, the magnetic attractive force generated between the south pole of the driving permanent magnet 2 and the north pole of the detection permanent magnet 5 is increased, and between the driving permanent magnet 2 and the detection permanent magnet 5 is increased. The attraction is stronger than the repulsion.

  The magnetic attractive force between the drive permanent magnet 2 and the detection permanent magnet 5 can facilitate the operation of fixing the detection permanent magnet 5 and the drive permanent magnet 2 to the support 10. Furthermore, since it is magnetically stable, it is possible to expect an increase in the fixing strength between the detection permanent magnet 5 and the drive permanent magnet 2.

  In the camera module 200, the distance between the driving permanent magnet 2 and the AF hall element 6 is larger than the distance between the driving permanent magnet 2 and the detection permanent magnet 5 when viewed from the optical axis direction. Therefore, the influence of the magnetic field generated by the driving permanent magnet 2 on the AF hall element 6 is small. For this reason, it is possible to expect an increase in gain margin of the AF control circuit.

(Modification)
The driving permanent magnet 2 may be disposed so that the south pole faces the AF coil 3 and the north pole faces the support 10. In this case, when a clockwise current is applied to the AF coil 3 as viewed from above, an upward Lorentz force is generated in the AF coil 3. The optical unit driving apparatus 1 displaces the optical unit 20 together with the lens holder 23 using the Lorentz force as a thrust. Therefore, the detection permanent magnet 5 is arranged below the AF coil 3 so that the south pole faces upward and the north pole faces downward.

  Alternatively, the detection permanent magnet 5 may be disposed above the AF coil, and the AF hall element 6 may be disposed above the drive permanent magnet 2. In this case, the direction of change in the magnetic field of the AF coil 3 sensed by the AF hall element 6 is reversed. Therefore, if the driving permanent magnet 2 is arranged so that the north pole faces the AF coil 3 and the south pole faces the support body 10, the detection permanent magnet 5 faces the south pole upward and the north pole. Is arranged so as to face downward. Further, if the driving permanent magnet 2 is disposed so that the south pole faces the AF coil 3 and the north pole faces the support 10, the detection permanent magnet 5 faces the north pole upward and the south pole. Is arranged so as to face downward.

[Embodiment 3]
The third embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 11 shows a schematic configuration of the camera module 300 according to the third embodiment, and is a cross-sectional view taken along line AA.

  Similar to the camera module 100 of the first embodiment, the camera module 300 has an AF function, the optical unit driving device 1, the optical unit 20, the imaging unit 30, the infrared blocking filter 34, the cover 40 in which the opening 41 is formed, and A wiring board (not shown) is provided.

  As in the first embodiment, the optical unit driving apparatus 1 includes a driving permanent magnet 2 (second permanent magnet), an AF coil 3, a detection permanent magnet 5, an AF hall element 6, an electric circuit unit 7, and a support. 10, an upper leaf spring 11, a lower leaf spring 12, a lens holder 23, and a base member 33. Similarly to the first embodiment, the optical unit 20 includes a plurality of imaging lenses 21 and a lens barrel 22. Similarly to the first embodiment, the imaging unit 30 includes an imaging element 31 and a substrate 32 perpendicular to the optical axis.

  Further, the optical unit driving apparatus 1 further includes an OIS coil 4 (second coil), a suspension wire 13, an OIS Hall element 8 (displacement detection unit) for an optical image stabilizer (OIS) function. ), And an OIS gyro sensor (not shown). Accordingly, the camera module 300 is different from the camera module 100 of the first embodiment and the camera module 200 of the second embodiment in that the OIS driving unit (the driving permanent magnet 2 and the OIS) moves the optical unit 20 in a direction perpendicular to the optical axis. Coil 4), a support member (suspension wire 13) that supports the optical unit 20 so that the optical unit 20 can swing in a direction perpendicular to the optical axis, and an OIS for detecting a displacement of the optical unit 20 in a direction perpendicular to the optical axis. A displacement detector (OIS Hall element 8).

  The OIS Hall element 8 is a magnetic displacement detection unit for detecting a displacement in a direction perpendicular to the optical axis of the optical unit 20 based on the magnetic field generated by the driving permanent magnet 2, and the magnetic flux density in the optical axis direction. It is arranged to measure the components. Further, when viewed from the optical axis direction, they are disposed near the center of the driving permanent magnet 2 disposed on the left side of the optical unit 20 and near the center of the driving permanent magnet 2 disposed on the front side. The OIS hall element 8 is fixed inside the base member 33.

  Thus, the OIS Hall element 8 is disposed below the driving permanent magnet 2 so as to measure the vertical component (z-axis direction) of the magnetic field generated by the driving permanent magnet 2. The OIS Hall element may be another type of magnetic displacement detector such as a magnetoresistive element, or may be a non-magnetic displacement detector using a light emitting element or the like.

  The suspension wire 13 is also a wiring member for energizing the AF coil 3 or the AF hall element 6. The suspension wire 13 is formed in a thin rod shape from metal or the like, and is disposed so as to extend in the direction of the optical axis. The lower end of the suspension wire 13 is fixed perpendicularly to the outer peripheral portion of the base member 33, and the upper end of the suspension wire 13 is fixed to the support 10 or the protruding portion of the outer end portion of the upper leaf spring 11. Therefore, the suspension wire 13 supports the support 10, the optical unit 20, and the AF driving unit (the driving permanent magnet 2 and the AF coil 3) so as to be swingable in a direction perpendicular to the optical axis.

  The detection permanent magnet 5 is disposed below the AF coil 3, and the AF hall element 6 is disposed below the drive permanent magnet 2. For this reason, if the drive permanent magnet 2 is arranged so that the N pole faces the AF coil 3, the detection permanent magnet 5 is arranged so that the N pole faces upward and the S pole faces downward. Is done. Further, if the driving permanent magnet 2 is arranged so that the south pole faces the AF coil 3, the detection permanent magnet 5 is arranged so that the south pole faces upward and the north pole faces downward. The

(OIS drive unit)
Below, the OIS drive section (the drive permanent magnet 2 and the OIS coil 4) will be described. In the third embodiment, the driving permanent magnet 2 is used as both the OIS driving unit and the AF driving unit. However, the OIS driving unit and the AF driving unit each have a dedicated driving permanent magnet. You may prepare.

  The OIS coil 4 is a planar coil, and is fixed to the base member 33 so as to face the lower surface having both magnetic poles of the driving permanent magnet 2. With this arrangement, when a current flows through the OIS coil 4, a Lorentz force in a direction perpendicular to the optical axis is generated in the OIS coil 4. And since the coil 4 for OIS is being fixed to the base member 33, the drive permanent magnet 2 which can be swung is displaced by using the reaction force of Lorentz force as a thrust. Since the driving permanent magnet 2 is fixed to the support body 10, the optical unit 20 is also displaced together with the driving permanent magnet 2 that can also swing through the upper plate spring 11 and the lower plate spring 12 and the lens holder 23. .

  Therefore, when an electric current is passed through the pair of OIS coils 4 arranged before and after the optical unit 20, a Lorentz force is generated in the front-rear direction perpendicular to the optical axis and the winding shaft, and the optical unit 20 is displaced in the front-rear direction. . Further, when a current is passed through the pair of OIS coils 4 arranged on the left and right of the optical unit 20, Lorentz force is generated in the left-right direction perpendicular to the optical axis and the winding shaft, and the optical unit 20 is displaced in the left-right direction. .

  In the third embodiment, the OIS coil 4 is provided at four positions on the front, rear, left, and right sides of the optical unit 20. However, the present invention is not limited to this. May be provided only on one of the left and right sides.

(3-axis feedback control)
The optical unit driving apparatus 1 having both the AF function and the OIS function displaces the optical unit in the triaxial direction (X axis, Y axis, Z axis). Therefore, in order to perform AF efficiently and at high speed, the position in the optical axis direction (z-axis direction) of the optical unit 20 and the direction perpendicular to the optical axis of the optical unit 20 based on the output signal of the OIS hall element 8 Based on the positions in the (X direction, Y direction), the AF control circuit performs three-axis feedback control on the AF drive unit.

(effect)
Similar to the first and second embodiments, the camera module 300 of the third embodiment has a large gain margin of the AF control circuit. For this reason, the AF control circuit hardly oscillates and is stable. Since the AF control circuit is stable, three-axis loop feedback control (see Patent Document 1) can be performed more effectively.

(Modification)
The detection permanent magnet 5 may be disposed above the AF coil 3, and the AF hall element 6 may be disposed above the driving permanent magnet 2. In this case, the direction of change in the magnetic field of the AF coil 3 sensed by the AF hall element 6 is reversed. Therefore, if the driving permanent magnet 2 is arranged so that the north pole faces the AF coil 3, the detection permanent magnet 5 is arranged so that the south pole faces upward and the north pole faces downward. The If the driving permanent magnet 2 is arranged so that the south pole faces the AF coil 3, the detection permanent magnet 5 is arranged so that the north pole faces upward and the south pole faces downward. The

  When the detection permanent magnet 5 and the AF hall element 6 are arranged above the AF drive unit (the AF coil 3 and the drive permanent magnet 2), the detection permanent magnet 5 and the AF hall element 6 are disposed. The distance between the OIS coil 4 and the AF hall element 6 is larger than when the two are disposed below the AF coil and the driving permanent magnet 2. Accordingly, since the OIS coil 4 and the AF hall element 6 are separated from each other, when the AF hall element 6 is disposed above the AF drive unit, the OIS coil 4 flows to the OIS coil 4 with respect to the AF hall element 6. The influence (noise) of the magnetic field generated by the current can be suppressed.

  For this reason, the OIS coil 4 and the AF hall element 6 are arranged by the configuration in which the AF hall element 6 is disposed between the AF drive unit (the AF coil 3 and the drive permanent magnet 2) and the OIS coil 4. In the configuration in which the AF driving unit (AF coil 3 and driving permanent magnet 2) is disposed between the two, the AF control circuit has a large gain margin and is stable.

  Similar to the first embodiment, also in the third embodiment, the driving permanent magnet 2 may be arranged so that the south pole faces the AF coil 3 and the north pole faces the support 10. Further, as in the second embodiment, the AF hall element 6 and the electric circuit unit 7 may be included in the AF movable unit, and the detection permanent magnet 5 may be included in the AF fixed unit.

[Embodiment 4]
The following description will discuss Embodiment 4 of the present invention with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 12 shows a schematic configuration of the camera module 400 according to the fourth embodiment, and is a cross-sectional view taken along line AA.

  13 shows a schematic configuration of the camera module 400 shown in FIG. 12, and is a cross-sectional view taken along line BB.

  Similarly to the camera module 100 of the first embodiment, the camera module 400 includes an AF function, the optical unit driving device 1, the optical unit 20, the imaging unit 30, the infrared blocking filter 34, the cover 40 in which the opening 41 is formed, and A wiring board (not shown) is provided.

  As in the first embodiment, the optical unit driving apparatus 1 includes a driving permanent magnet 2, an AF coil 3, a detection permanent magnet 5, an AF hall element 6, an electric circuit unit 7, a support 10, and an upper leaf spring 11. The lower leaf spring 12, the lens holder 23, and the base member 33 are provided. Similarly to the first embodiment, the optical unit 20 includes a plurality of imaging lenses 21 and a lens barrel 22. Similarly to the first embodiment, the imaging unit 30 includes an imaging element 31 and a substrate 32 perpendicular to the optical axis.

[Arrangement of permanent magnet for detection and hall element for AF]
Unlike the camera modules 100, 200, and 300 of the first to third embodiments, in the camera module 400 of the fourth embodiment, the detection permanent magnet 5, the AF hall element 6, and the electric circuit unit 7 are optically driven. Arranged at the corners of the device 1.

  Hereinafter, the arrangement of the detection permanent magnet 5, the AF hall element 6, and the electric circuit unit 7 will be described with reference to FIGS.

  The detection permanent magnet 5 is arranged below the AF coil 3 so that the north pole faces upward and the south pole faces downward. Further, the detection permanent magnet 5 is fixed to the lens holder 23 so as to be arranged on the outer peripheral side surface on the left rear side of the lens holder 23.

  The AF hall element 6 and the electric circuit unit 7 are disposed below the driving permanent magnet 2. In addition, the AF Hall element 6 and the electric circuit portion 7 are fixed to the support body 10 so as to be arranged at the corners of the inner peripheral side surface on the left rear side of the support body 10.

  Therefore, the detection permanent magnet 5 and the AF hall element 6 are arranged at the left rear corner of the optical unit driving device 1 so as to face each other when viewed from the optical axis direction. For this reason, the detection permanent magnet 5 and the AF hall element 6 are, as viewed from the optical axis direction, the drive permanent magnet 2 disposed behind the optical unit 20 and the drive permanent magnet 2 disposed on the left side. It is arranged between.

  With this arrangement, the AF hall element 6 is separated from the driving permanent magnet 2 as compared with the first to third embodiments. Thereby, the influence (noise) of the magnetic field of the driving permanent magnet 2 on the AF hall element 6 can be suppressed.

  Similarly to the first embodiment, in the fourth embodiment, the driving permanent magnet 2 may be arranged so that the south pole faces the AF coil 3 and the north pole faces the support 10. Further, the detection permanent magnet 5 and the AF hall element 6 may be disposed above the AF drive unit. Further, as in the second embodiment, the AF hall element 6 and the electric circuit unit 7 may be included in the AF movable unit, and the detection permanent magnet 5 may be included in the AF fixed unit.

  Further, in the second and third embodiments, as in the fourth embodiment, the detection permanent magnet 5, the AF hall element 6, and the electric circuit unit 7 may be arranged at the corner of the optical unit driving device 1.

[Summary]
An optical unit driving apparatus according to aspect 1 of the present invention includes an optical unit (20) having an imaging lens (21), a support (10) that supports the optical unit, and the optical unit with respect to the support. First permanent magnet (driving permanent magnet 2) and first coil (AF coil 3) for displacing in the optical axis direction (z-axis direction) of the imaging lens, and displacement of the optical unit in the optical axis direction And a permanent magnet for detection (relative to the magnetic displacement detector in accordance with the displacement in the optical axis direction of the optical part) 5), a first component (signal component) that is a magnetic field generated by the permanent magnet for detection detected by the magnetic displacement detector, and the magnetic displacement Generated by the current flowing through the first coil detected by the detector The second component is a magnetic field (noise component), the same phase when a direct current flows to the first coil.

  According to the above configuration, the first component and the second component have the same phase when a direct current is passed through the first coil. For this reason, the first component and the second component have the same phase in a frequency band lower than the primary resonance frequency of the first permanent magnet and the first coil. In the frequency band higher than the primary resonance frequency of the first permanent magnet and the first coil, the first component and the second component are in opposite phases and have a magnetic anti-resonance frequency. Furthermore, the output of the magnetic displacement detector is mainly the sum of the first component and the second component.

  For this reason, in the frequency band around the anti-resonance frequency (region II in FIG. 9), the first component and the second component have a phase opposite to that when a direct current is passed through the first coil. Thus, the gain of the output of the magnetic displacement detector in the above configuration is small. As a result, the gain margin of the control circuit in the frequency band higher than the control frequency of the control circuit (AF control circuit) that controls the current flowing through the first coil can be increased based on the output of the magnetic displacement detector.

  Since the gain margin of the control circuit is large, the control circuit is less likely to oscillate even when resonance other than the resonance between the first coil and the first permanent magnet exists. As described above, according to the above configuration, the optical unit can be obtained without reducing the gain of the control circuit or mechanically changing the resonance frequency of the resonance other than the resonance between the first coil and the first permanent magnet. The displacement (autofocus) in the optical axis direction can be feedback controlled more stably.

  An optical unit driving apparatus according to Aspect 2 of the present invention is the optical unit driving apparatus (1) according to Aspect 1, wherein the first component (signal component) and the second component (noise component) are When an alternating current is passed through the first coil (AF coil 3), it may have a magnetic antiresonance frequency (antiresonance point 72a).

  According to the above configuration, the first component and the second component have a magnetic anti-resonance frequency. For this reason, since the gain margin of the control circuit for controlling the current flowing through the first coil is large as in the first aspect, the displacement (autofocus) of the optical unit in the optical axis direction can be feedback-controlled more stably.

  An optical unit driving apparatus according to Aspect 3 of the present invention is the optical unit driving apparatus (1) according to Aspect 1 or 2, wherein the magnetic displacement detection unit (AF Hall element 6) is in the optical axis direction. Are arranged so as to detect a magnetic field in a first direction (y-axis direction) perpendicular to the first permanent magnet (5). It may be arranged so that the other of the magnetic poles (S pole) is directed to the other of the optical axis directions (downward, −z direction).

  According to said structure, the direction (y-axis direction) which detects the magnetic field of a magnetic displacement detection part, and the direction (z-axis direction) which connects both the magnetic poles of a permanent magnet for a detection are orthogonal. With this arrangement, the first component (signal component) changes linearly with respect to the displacement of the detection permanent magnet. Since it changes linearly, the control circuit can easily calculate the displacement of the permanent magnet for detection, that is, the displacement of the optical unit, from the first component.

  Therefore, the control circuit can be simplified, and the displacement (autofocus) of the optical unit in the optical axis direction can be more easily feedback controlled.

  An optical unit driving device according to aspect 4 of the present invention is the optical unit driving device (1) according to any one of the above aspects 1 to 3, wherein the magnetic displacement detection unit (AF Hall element 6) and One of the detection permanent magnet (5) and the first coil (AF coil 3) are fixed to the optical unit (20), and the magnetic displacement detection unit and the detection permanent magnet The other and the first permanent magnet (driving permanent magnet 2) are fixed to the support (10), and the first permanent magnet has a surface facing the first coil, and a magnetic pole. May be arranged so that one of them is directed to one of the second directions perpendicular to the optical axis and the other of the magnetic poles is directed to the other of the second directions.

  According to said structure, when an electric current is sent through a 1st coil, the Lorentz force of an optical axis direction will generate | occur | produce in a 1st coil. Since the optical unit is displaced in the optical axis direction by the Lorentz force, the control circuit that controls the current flowing through the first coil can control the displacement of the optical unit in the optical axis direction.

  An optical unit driving apparatus according to Aspect 5 of the present invention is the optical unit driving apparatus (1) according to Aspect 4, wherein the first permanent magnet (driving permanent magnet 2) is in the optical axis direction (z-axis). Viewed from the direction), one of the magnetic poles (S pole) is arranged to be farther from the magnetic displacement detector (AF Hall element 6) than the other (N pole), and the permanent magnet for detection (5) The magnetic poles (N poles) are arranged so as to overlap the one (S pole) of the magnetic poles of the first permanent magnet when viewed from the optical axis direction, and the detection permanent magnets are directed to the first permanent magnet. And attraction may generate | occur | produce between said one side (S pole) of the magnetic pole of said 1st permanent magnet.

  According to said structure, a 1st permanent magnet and a permanent magnet for a detection are magnetically stable arrangement | positioning. For this reason, in the assembly work, the work of arranging (fixing) the first permanent magnet and the detection permanent magnet can be facilitated. It is also possible to expect an increase in the fixing strength between the first permanent magnet and the detection permanent magnet.

  An optical unit driving apparatus according to an aspect 6 of the present invention is the optical unit driving apparatus (1) according to any one of the above aspects 1 to 3, wherein the first permanent magnet (driving permanent magnet 2) and the The detection permanent magnet (5) is fixed to one of the optical unit (20) and the support (10), and the first permanent magnet is directed to the one of the optical unit and the support. An attractive force may be generated between the magnetic pole and the magnetic pole that the detection permanent magnet faces toward the first permanent magnet.

  According to said structure, a 1st permanent magnet and a permanent magnet for a detection are magnetically stable arrangement | positioning. For this reason, in the assembly work, the work of arranging (fixing) the first permanent magnet and the detection permanent magnet can be facilitated. It is also possible to expect an increase in the fixing strength between the first permanent magnet and the detection permanent magnet.

  An optical unit driving apparatus according to an aspect 7 of the present invention is the optical unit driving apparatus (1) according to any one of the above aspects 1 to 6, and a plurality of the first permanent magnets (driving permanent magnets 2). The magnetic displacement detector (AF Hall element 6) and the detection permanent magnet (5) are viewed from the optical axis direction (z-axis direction). The magnet pieces may be disposed between two adjacent magnet pieces (the driving permanent magnet 2 disposed behind the optical unit 20 and the driving permanent magnet 2 disposed on the left side).

  According to said structure, the magnetic displacement detection part and the permanent magnet for a detection are arrange | positioned between two magnet pieces. In other words, the magnetic displacement detector and the detection permanent magnet are disposed where there is no magnet piece that is the first permanent magnet, and are separated from the first permanent magnet. For this reason, according to the said structure, the influence of the magnetic field which a 1st permanent magnet produces | generates with respect to a magnetic displacement detection part can be suppressed.

  An optical unit driving apparatus according to an eighth aspect of the present invention is the optical unit driving apparatus (1) according to any one of the first to sixth aspects, wherein the first permanent magnet (driving permanent magnet 2) is small. Also includes one magnet piece (driving permanent magnet 2), and the magnetic displacement detector (AF Hall element 6) and the detecting permanent magnet (5) are separated from the optical axis direction (z-axis direction). As seen, it may be arranged near the center of the long side of the magnet piece.

  Generally, in the vicinity of the center of the long side of the magnet piece, the long side of the magnet piece and the first coil face each other in parallel. For this reason, according to said structure, a magnetic displacement detection part and a permanent magnet for a detection can be easily arrange | positioned so that it may mutually oppose in parallel.

  An optical unit driving apparatus according to an aspect 9 of the present invention is the optical unit driving apparatus (1) according to any one of the above aspects 1 to 8, and the optical unit (20) is arranged in the optical axis direction (z axis). Auto focus (Auto Focus, AF) may be performed by displacing in the direction.

  According to said structure, the optical part drive device which carries out autofocus is realizable.

  An optical unit driving apparatus according to aspect 10 of the present invention is the optical unit driving apparatus (1) according to any one of the above aspects 1 to 9, wherein the magnetic displacement detection unit (AF Hall element 6) Based on the output, the current flowing through the first coil (AF coil 3) may be feedback controlled.

  According to the above configuration, the displacement of the optical unit in the optical axis direction can be feedback controlled.

  An optical unit driving apparatus according to an eleventh aspect of the present invention is the optical unit driving apparatus (1) according to any one of the first to tenth aspects, wherein the optical unit (20) is perpendicular to the optical axis direction. A second permanent magnet (driving permanent magnet 2) and a second coil (OIS coil 4) for displacement in the third direction (x-axis direction, y-axis direction) may be provided.

  According to said structure, the optical part drive device which can displace an optical part to an optical axis direction (z-axis direction) and two directions (x-axis direction, y-axis direction) perpendicular | vertical to an optical axis is provided. realizable.

  An optical unit driving apparatus according to aspect 12 of the present invention is the optical unit driving apparatus (1) according to aspect 11 described above, and the first permanent magnet (driving permanent magnet) in the optical axis direction (z-axis direction). The magnetic displacement detector (AF Hall element 6) may be disposed between 2) and the second coil (OIS coil 4).

  According to said structure, a 2nd coil and a magnetic displacement detection part are near. Since they are close, the wiring can be shortened and the wiring of the optical unit driving device can be simplified.

  An optical unit driving apparatus according to an aspect 13 of the present invention is the optical unit driving apparatus (1) according to the above aspect 11, and the magnetic displacement detection unit (AF hole) in the optical axis direction (z-axis direction). The first permanent magnet (driving permanent magnet 2) may be disposed between the element 6) and the second coil (OIS coil 4).

  According to said structure, a 2nd coil and a magnetic displacement detection part are far. Since it is far, the influence of the magnetic field generated by the current flowing through the second coil on the magnetic displacement detector can be suppressed.

  An optical unit driving device according to aspect 14 of the present invention is the optical unit driving device (1) according to any one of the above aspects 11 to 13, and the third direction (x-axis) of the optical unit (20). A displacement detector for detecting a displacement in the direction and the y-axis direction, and based on the output of the magnetic displacement detector (6) and the output of the displacement detector, the first coil (AF coil 3). ) May be feedback controlled.

  According to the above configuration, the control of the displacement of the optical unit in the optical axis direction is interlocked with the displacement of the optical unit in the third direction. For this reason, when the optical unit is displaced in the optical axis direction and the third direction at the same time, it is possible to control the displacement of the optical unit in the optical axis direction at high speed.

  An optical unit driving apparatus according to aspect 15 of the present invention is the optical unit driving apparatus (1) according to any one of the above aspects 11 to 14, wherein the first permanent magnet (driving permanent magnet 2) is It may also serve as the second permanent magnet (driving permanent magnet 2).

  According to said structure, a 1st permanent magnet serves as said 2nd permanent magnet. Therefore, the number of members constituting the optical unit driving device can be reduced. For this reason, it becomes possible to reduce the manufacturing cost and weight of an optical part drive device.

  The camera module (100, 200, 300, 400) according to aspect 16 of the present invention may include the optical unit driving device (1) according to any one of aspects 1 to 15.

  According to said structure, a camera module provided with the optical part drive device as described in any one aspect of the aspects 1-15 is realizable.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

DESCRIPTION OF SYMBOLS 1 Optical part drive device 2 Permanent magnet for a drive (1st permanent magnet, 2nd permanent magnet)
3 AF coil (first coil)
4 OIS coil (second coil)
5 Permanent magnet for detection 6 Hall element for AF (magnetic displacement detector)
7 Electrical circuit 8 Hall element for OIS (displacement detector)
DESCRIPTION OF SYMBOLS 10 Support body 11 Upper leaf | plate spring 12 Lower leaf | plate spring 13 Suspension wire 20 Optical part 21 Imaging lens 22 Lens barrel 23 Lens holder 30 Imaging part 31 Imaging element 32 Board | substrate 33 Base member 34 Infrared cutoff filter 40 Cover 41 Opening 61-63 Phase characteristic 71-73 Gain characteristics 72a Anti-resonance point (anti-resonance frequency)
100, 200, 300, 400 Camera module B11, B12 Magnetic field of permanent magnet for detection (magnetic field generated by permanent magnet for detection)
B21, B22 Magnetic field of AF coil (magnetic field generated by current flowing through first coil)

Claims (4)

An optical unit having an imaging lens;
A first permanent magnet and a first coil for displacing the optical unit in the optical axis direction of the imaging lens with respect to the support;
A magnetic displacement detector for detecting displacement of the optical unit in the optical axis direction;
A detection permanent magnet that is displaced relative to the magnetic displacement detection unit in accordance with the displacement of the optical unit in the optical axis direction.
A first component that is a magnetic field generated by the detection permanent magnet detected by the magnetic displacement detector, and a second component that is a magnetic field generated by a current flowing in the first coil detected by the magnetic displacement detector. the, Ri same phase der when a direct current flows to the first coil,
The first component and the second component have a magnetic anti-resonance frequency when an alternating current is passed through the first coil,
Wherein in the magnetic anti-resonance frequency, optic drive phase difference characterized that you transition 180 ° between the current flowing through the first coil and the output of the magnetic displacement detecting unit. The magnetic displacement detector is arranged to detect a magnetic field in a first direction perpendicular to the optical axis direction,
2. The optical device according to claim 1 , wherein the permanent magnet for detection is arranged so that one of the magnetic poles faces one side in the optical axis direction and the other magnetic pole faces the other side in the optical axis direction. Part drive device. A second permanent magnet and a second coil for displacing the optical unit in a third direction perpendicular to the optical axis direction;
A displacement detection unit for detecting a displacement of the optical unit in the third direction,
3. The optical unit driving apparatus according to claim 1, wherein feedback control is performed on a current flowing through the first coil based on an output of the magnetic displacement detection unit and an output of the displacement detection unit. Camera module comprising the optical unit driving apparatus according to any one of claims 1 to 3.

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