Drive device, camera module, and camera-equipped device

Abstract

This drive device comprises a movable part, an accommodation part, a drive unit, and a detection unit for detecting the position of the movable part. The detection unit includes a movable-side electrode disposed on the movable part, and a fixed-side electrode disposed in the accommodation part so as to oppose the movable-side electrode. The fixed-side electrode extends along an optical axis direction such that the capacitance between the movable-side electrode and the fixed-side electrode varies according to the position of the movable part.

Description

Drive device, camera module, and camera-mounted device

[0001] The present invention relates to a drive device, a camera module, and a camera-mounted device.

[0002] Conventionally, a camera module mounted on a thin camera-mounted device such as a smartphone is known. Such a camera module is known to include a drive device having a zoom function for enlarging or reducing a subject image.

[0003] In such a drive device, it is desirable to accurately detect the position of a movable part driven by a drive part. For example, in Patent Document 1, the position of the movable part is detected by a position detection part that detects the magnetic flux of a magnet part provided on the movable part.

[0004] International Publication No. 2021 / 200012

[0005] By the way, considering the influence on the outside of the camera module, a configuration capable of accurately detecting the position of the movable part without using a magnet part is desirable.

[0006] An object of the present invention is to provide a drive device, a camera module, and a camera-mounted device capable of accurately detecting the position of a movable part without using a magnet part.

[0007] The drive device according to the present invention includes: a movable part movable in the optical axis direction; a housing part that houses the movable part; a drive part that moves the movable part in the optical axis direction within the housing part; and a detection part for detecting the position of the movable part. The detection part includes a movable-side electrode disposed on the movable part and a fixed-side electrode disposed opposite to the movable-side electrode in the housing part. The fixed-side electrode extends along the optical axis direction such that the capacitance between the movable-side electrode and the fixed-side electrode varies according to the position of the movable part.

[0008] The camera module according to the present invention includes: the above drive device; an element part including an optical element held by the movable part; and an imaging part that images a subject image formed by the element part.

[0009] The camera-mounted device according to the present invention is a camera-mounted device which is an information device or a transport device, and comprises the above-mentioned camera module and an imaging control unit which processes image information obtained by the camera module.

[0010] According to the present invention, the position of the movable part can be detected with high accuracy without using a magnet.

[0011] This is a diagram showing a smartphone equipped with a camera module. This is a diagram showing a smartphone equipped with a camera module. This is a simplified diagram showing a camera module according to an embodiment of the present invention. This is a simplified diagram showing a side view of the camera module according to this embodiment. This is a perspective view showing the housing portion of the camera module. This is a perspective view of the bottom wall portion of the housing portion of the camera module. This is an exploded perspective view of the housing and the lens portion. This is a view of the housing from the Z-direction + side. This is a view of the lens drive unit from the side. This is a perspective view of the lens drive unit. This is a cross-sectional view showing the insert portion of the bottom portion into the side portion. This is an exploded perspective view of the intervening portion and the frame. This is a perspective view of the ultrasonic motor. This is an exploded perspective view of the ultrasonic motor. This is an enlarged view of the contact portion between the resonant portion and the intervening portion. This is a diagram showing the detection unit. This is a diagram for explaining the operation of the detection unit. This is a diagram for explaining the operation of the detection unit. This is a diagram showing an automobile equipped with a camera module. This is a diagram showing an automobile equipped with a camera module.

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Figure 2 is a simplified diagram showing a camera module 1 according to an embodiment of the present invention. Figure 3 is a simplified diagram showing a side view of the camera module 1 according to this embodiment.

[0013] Camera module 1 is mounted on thin camera-equipped devices such as smartphones M (see Figures 1A and 1B), mobile phones, digital cameras, notebook computers, tablet devices, portable game consoles, and in-car cameras.

[0014] In describing the structure of the camera module 1 in this embodiment, we will use a Cartesian coordinate system (X, Y, Z). The same Cartesian coordinate system (X, Y, Z) will also be used in the figures described later. When the camera module 1 is actually mounted on the camera-mounted device, for example, the X direction is the left-right direction, the Y direction is the up-down direction, and the Z direction is the front-back direction. Light from the subject enters the camera module 1 from the Z-direction + side, bends from the entry point, and is guided to the Y-direction + side. By reducing the thickness of the camera module 1 in the Z direction, the camera-mounted device can be made thinner.

[0015] As shown in Figure 2, the camera module 1 comprises a housing 10, a reflection drive unit 20, a lens unit 30, an imaging unit 40, a guide unit 50 (see Figure 4), a lens drive unit 60 (see Figure 6), a detection unit 70 (see Figure 10), and a drive control unit 100.

[0016] The drive control unit 100 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The CPU reads a program corresponding to the processing content from the ROM, loads it into the RAM, and works in cooperation with the loaded program to centrally control the lens drive unit 60. As a result, the drive control unit 100 drives the second lens unit 32 and the third lens unit 33, which will be described later, of the lens unit 30 housed in the housing 10 in the Y direction (direction of the optical axis). As a result, the camera module 1 performs stepless optical zoom and autofocus. The housing 10, guide unit 50, lens drive unit 60, detection unit 70, and drive control unit 100 correspond to the "drive device" of the present invention.

[0017] Furthermore, as shown in Figure 3, in the camera module 1, incident light L1 is incident on the housing 10 via the reflection drive unit 20. The reflection drive unit 20 includes a reflection housing 21, a mirror 22, and a reflection drive control unit 23. In the example shown in Figures 2 and 3, the reflection housing 21 is positioned adjacent to the negative end in the Y direction of the housing 10. The mirror 22 is provided inside the reflection housing 21 and reflects the incident light L1 as reflected light L2 toward the housing 10. The reflection drive control unit 23 includes a CPU, ROM, RAM, etc., and controls the orientation of the mirror 22.

[0018] Furthermore, the mirror 22 according to this embodiment has two rotation axes (not shown) extending in the X and Y directions. In the reflection drive unit 20, the mirror 22 rotates around these rotation axes under the control of the reflection drive control unit 23. As a result, the camera module 1 has a shake correction function (OIS (Optical Image Stabilization) function) that optically corrects shake (vibration) that occurs during shooting and reduces image distortion.

[0019] The reflected light L2 that enters the housing 10 is output to the imaging unit 40 via the lens unit 30 housed within the housing 10.

[0020] The imaging unit 40 is positioned on the positive side outer surface of the housing 10 in the Y direction (the position 112A of the second wall 112, which will be described later), and is configured to receive reflected light L2 through the lens unit 30. The imaging unit 40 includes an image sensor and a substrate, etc. (not shown).

[0021] The image sensor is composed of, for example, a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal Oxide Semiconductor) type image sensor. The image sensor is mounted on a substrate and electrically connected to the wiring on the substrate via bonding wires. The image sensor captures an image of the subject formed by the lens unit 30 and outputs an electrical signal corresponding to the subject image.

[0022] Furthermore, a printed circuit board (not shown) is electrically connected to the substrate of the imaging unit 40, and power is supplied to the image sensor and electrical signals of the subject image captured by the image sensor are output via this printed circuit board. These electrical signals are output to an imaging control unit 200 provided in the camera mounting device. The imaging control unit 200 includes a CPU, ROM, RAM, etc., and processes the image information obtained by the camera module 1. The imaging control unit 200 may be mounted in the camera mounting device, but it may also be built into the camera module 1.

[0023] As shown in Figures 4 and 5, the housing 10 houses the lens section 30, the guide section 50, the lens drive section 60 (see also Figure 6), and the detection section 70 (see also Figure 10), and for example, has a rectangular parallelepiped shape overall. The housing 10 has side walls 11 and a bottom wall 12. The housing 10 corresponds to the "housing section" of the present invention.

[0024] The side wall portion 11 is a wall portion made of, for example, resin, that constitutes the side wall of the housing 10, and has a first wall 111, a second wall 112, and a third wall 113.

[0025] The first wall 111 extends in the Y direction and is provided in pairs on both sides in the X direction. The first wall 111 is provided with an arrangement section 111A on the inner surface of the housing 10 for arranging the ultrasonic motor 64, which will be described later.

[0026] As shown in Figures 4, 5, and 6, the second wall 112 extends in the X direction and is provided to connect the Y-direction + side ends of the pair of first walls 111. Inside the second wall 112, there is a configuration section 112A where the fourth lens unit 34 of the lens section 30 is arranged. An opening 112B is provided in the portion of the second wall 112 facing the fourth lens unit 34.

[0027] Furthermore, a first axial support portion 112C and a second axial support portion 112D are provided on each of the X-direction sides of the opening 112B of the second wall 112. The first axial support portion 112C is a hole that supports the first guide shaft 51, which will be described later. The second axial support portion 112D is a hole that supports the second guide shaft 52, which will be described later, and is located on the negative side in the Z direction than the first axial support portion 112C.

[0028] The third wall 113 is provided to connect the Y-side ends of the pair of first walls 111. Inside the third wall 113, there is an arrangement section 113A where the first lens unit 31 of the lens section 30 is arranged. An opening 113B is provided in the portion of the third wall 113 facing the first lens unit 31.

[0029] Furthermore, a third axial support portion 113C and a fourth axial support portion 113D are provided on each of the X-direction sides of the opening 113B of the third wall 113. The third axial support portion 113C is a hole that supports the first guide shaft 51, which will be described later. The fourth axial support portion 113D is a hole that supports the second guide shaft 52, which will be described later, and is located on the negative side in the Z direction than the third axial support portion 113C.

[0030] In this embodiment, the height of the third axial support portion 113C is the same as the height of the first axial support portion 112C of the second wall 112 described above. Also, the height of the fourth axial support portion 113D is the same as the height of the second axial support portion 112D of the second wall 112 described above.

[0031] The bottom wall portion 12 constitutes the bottom wall of the housing 10. A substrate placement portion 12A is provided at the negative end of the bottom wall portion 12 in the X direction. The substrate placement portion 12A is a portion for placing the substrate 130. The substrate placement portion 12A protrudes in the X direction from a position corresponding to the first wall 111 of the bottom wall portion 12.

[0032] Furthermore, a gap is formed between the first wall 111 and the substrate placement area 12A. As shown in Figure 7, the substrate 130 is positioned in the area from the part of the bottom wall 12 inside the first wall 111 to the part of the substrate placement area 12A, through the gap. The part of the substrate 130 positioned outside the housing 10 (the part of the substrate placement area 12A) is connected to predetermined wiring of the camera mounting device.

[0033] The substrate 130 also has a first portion 131, a second portion 132, and a third portion 133. The first portion 131 is arranged along the first wall 111 on the negative side in the X direction and is connected to the lens drive unit 60 of the third lens unit 33, which will be described later. The second portion 132 is arranged along the second wall 112 and connects the first portion 131 and the third portion 133. The third portion 133 is arranged along the first wall 111 on the positive side in the X direction and is connected to the lens drive unit 60 of the second lens unit 32, which will be described later.

[0034] As shown in Figures 4 and 6, the lens section 30 is provided in a region sandwiched between a pair of first walls 111, which includes the region through which reflected light L2 (see Figure 3) from the reflection drive unit 20 passes. The lens section 30 has a first lens unit 31, a second lens unit 32, a third lens unit 33, and a fourth lens unit 34 arranged side by side in the Y direction. Each of the first lens unit 31, the second lens unit 32, the third lens unit 33, and the fourth lens unit 34 houses a lens.

[0035] The first lens unit 31 is positioned on the upstream side in the incident direction of reflected light L2 (direction toward the positive side in the Y direction) and is fixed to the positioning portion 113A of the third wall 113 of the housing 10.

[0036] The second lens unit 32 is positioned downstream of the first lens unit 31 in the incident direction and is held by the frame 61 of the lens drive unit 60, which will be described later. The second lens unit 32 is movable in the Y direction by the lens drive unit 60.

[0037] The third lens unit 33 is positioned downstream of the second lens unit 32 in the incident direction and is held by the frame 61 of the lens drive unit 60, which will be described later. The third lens unit 33 is movable in the Y direction by the lens drive unit 60.

[0038] The fourth lens unit 34 is positioned on the downstream side in the incident direction and is fixed to the mounting portion 112A of the second wall 112 of the housing 10.

[0039] The lenses in the first to fourth lens units 31 to 34 may be assembled to the housing 10 during the manufacturing of the drive unit, or they may be assembled to the housing 10 when the camera module 1 is manufactured from the lens drive unit 60.

[0040] As shown in Figure 6, the guide section 50 guides the movement of the second lens unit 32 and the third lens unit 33. The guide section 50 has a first guide shaft 51 and a second guide shaft 52. The first guide shaft 51 and the second guide shaft 52 are made of, for example, a metal material and extend in the Y direction.

[0041] The first guide shaft 51 is supported by the first shaft support portion 112C of the second wall 112 and the third shaft support portion 113C of the third wall 113. The second guide shaft 52 is supported by the second shaft support portion 112D of the second wall 112 and the fourth shaft support portion 113D of the third wall 113, and is positioned at a different height from that of the first guide shaft 51.

[0042] Furthermore, as shown in Figure 7, each of the pair of first walls 111 described above has, for example, substantially the same shape and is symmetrically arranged with respect to the optical axis O of the lens portion 30 on both sides in the X direction. Specifically, each of the pair of first walls 111 is symmetrically arranged with respect to the optical axis O such that each of the pair of first walls 111 is positioned at a predetermined distance from the optical axis O.

[0043] Furthermore, the pair of first guide axes 51 and the pair of second guide axes 52, supported by the second wall 112 and the third wall 113 respectively, are arranged symmetrically with respect to the optical axis O. More specifically, the pair of first guide axes 51 and the pair of second guide axes 52 are arranged such that their distances from the optical axis O are equal.

[0044] The lens driving unit 60 is provided corresponding to each of the second lens unit 32 and the third lens unit 33, and independently moves either the corresponding second lens unit 32 or the third lens unit 33 under the control of the above-described driving control unit 100. The lens driving unit 60 is disposed in a region between each of the pair of first walls 111 and each of the pair of first guide shafts 51 (second guide shafts 52). That is, one lens driving unit 60 is provided on each side of the optical axis in the housing 10.

[0045] In the present embodiment, the lens driving unit 60 on the + side in the X direction drives the second lens unit 32 in the Y direction, and the lens driving unit 60 on the - side in the X direction drives the third lens unit 33 in the Y direction. That is, the lens driving units 60 on the + side and the - side in the X direction correspond to the "driving unit" of the present invention.

[0046] In the present embodiment, since each lens driving unit 60 has substantially the same shape, in the following description, unless otherwise specified, only the lens driving unit 60 corresponding to the second lens unit 32 will be described, and the description of the lens driving unit 60 corresponding to the third lens unit 33 will be omitted. Also, in the present embodiment, since each lens driving unit 60 is symmetrically arranged in the X direction and the Y direction, the relationship between the + side and the - side in the direction of the lens driving unit 60 corresponding to the third lens unit 33 is opposite to the relationship between the + side and the - side in the direction of the lens driving unit 60 corresponding to the second lens unit 32. Also, in the following description, the second lens unit 32 and the third lens unit 33 will be referred to as movable lenses.

[0047] As shown in FIG. 8, the lens driving unit 60 includes a frame 61, an intervening portion 63, and an ultrasonic motor 64.

[0048] As shown in FIG. 9, the frame 61 is supported by the guide portion 50 (first guide shaft 51) while supporting the movable lens, and moves together with the movable lens. The movable lens and the frame 61 correspond to the "movable part" of the present invention. The frame 61 has a holding portion 611, an inserted portion 612, a first contact portion 613, and a second contact portion 614.

[0049] The holding portion 611 is the part that holds the movable lens and is positioned between the guide portions 50 on both sides in the X direction. The holding portion 611 has a bottom portion 611A and a pair of side portions 611B.

[0050] The bottom portion 611A extends in the X direction and is positioned opposite the bottom wall portion 12. The pair of side portions 611B extend from both ends of the bottom portion 611A in the X direction to the + side in the Z direction. The holding portion 611 holds the movable lens by surrounding it with the bottom portion 611A and the pair of side portions 611B.

[0051] Furthermore, as shown in Figure 10, the bottom portion 611A is made of a metal material and is insert-molded into each of the pair of side portions 611B. The portion of the bottom portion 611A inserted into each side portion 611B is shaped to conform to the shape of each side portion 611B. As a result, the bottom portion 611A is integrally formed with each side portion 611B. The second lens unit 32 (third lens unit 33) is adhesively fixed to the bottom portion 611A. Note that the method of fixing the second lens unit 32 (third lens unit 33) to the bottom portion 611A can be any method as long as the second lens unit 32 (third lens unit 33) can be fixed.

[0052] As shown in Figures 9 and 10, the insertion portion 612 is the portion through which the first guide shaft 51 is inserted, and is provided on the positive side portion 611B in the X direction of the pair of side portions 611B. The insertion portion 612 is provided projecting from the positive end in the Z direction of the side portion 611B toward the positive side in the X direction. A hole is formed in the portion of the insertion portion 612 corresponding to the first guide shaft 51 through which the first guide shaft 51 is inserted. This hole has a diameter such that the first guide shaft 51 is inserted into the insertion portion 612 with some clearance. By inserting the first guide shaft 51 into this insertion portion 612, the frame 61 is prevented from deviating from the guide portion 50 due to vibrations caused by external forces, etc.

[0053] The first contact portion 613 is provided on the negative side portion 611B in the X direction of one of the pair of side portions 611B, and is positioned to contact the negative side first guide shaft 51 in the X direction of one of the pair of first guide shafts 51. Specifically, the first contact portion 613 protrudes from the side portion 611B in the negative side of the X direction and is positioned to contact the first guide shaft 51 from the positive side in the Z direction of the first guide shaft 51. The first contact portion 613 may also be provided with a biasing member, such as a magnet, to bias the first contact portion 613 toward the first guide shaft 51.

[0054] The second contact portion 614 extends from the insertion portion 612 to the positive side in the Y direction and is positioned between the first guide shaft 51 and the second guide shaft 52. The second contact portion 614 contacts the second guide shaft 52 from the positive side in the Z direction. The second contact portion 614 may be provided with a biasing member, such as a magnet, to bias the second contact portion 614 toward the second guide shaft 52.

[0055] As shown in Figure 11, the intervening portion 63 is made of, for example, a plate-shaped metal member and is fixed to the side of the frame 61 opposite to the movable lens at the second contact portion 614. The intervening portion 63 has a main body portion 631 and a contact portion 632.

[0056] The main body portion 631 has a plane parallel to the direction of the optical axis (Y direction) and is adhesively fixed to the second contact portion 614 via the fixed portion 621A.

[0057] The contact portion 632 is the part that the transducer of the ultrasonic motor 64 makes contact with, and is formed by bending both ends of the main body portion 631 in the Z direction toward the opposite side from the lens portion.

[0058] With the contact portion 632 configured in this way, a force is applied from the transducer of the ultrasonic motor 64 to the contact portion 632, generating thrust in the direction of the optical axis (Y direction) in the intervening portion 63. This makes it possible to impart thrust from the intervening portion 63 to the frame 61, moving it in the direction of the optical axis (Y direction).

[0059] Furthermore, a plate-shaped member 633 is provided at each contact portion 632. The plate-shaped member 633 is a flat member and is made of a hard material such as ceramic or metal. One plate-shaped member 633 is provided at each contact portion 632 so as to sandwich the contact portion 632 from both sides in the Z direction.

[0060] As shown in Figure 12, the ultrasonic motor 64 is a drive source that generates the driving force to move the frame 61, and is fixedly positioned in each of the arrangement portions 111A of the pair of first walls 111. The ultrasonic motor 64 has a resonant portion 641, a piezoelectric element 642, and an electrode 643.

[0061] As shown in Figure 13, the resonant portion 641 is formed of, for example, a conductive material and resonates with the vibration of the piezoelectric element 642, converting the vibrational motion into linear motion of the frame 61. Specifically, the resonant portion 641 vibrates in an inclined direction that is tilted with respect to the direction of the optical axis (Y direction) based on the vibration of the piezoelectric element 642, and presses against the intervening portion 63. This generates a thrust that moves the frame 61 in the direction of the optical axis via the intervening portion 63. The resonant portion 641 is positioned so as to be sandwiched between two contact portions 632 of the intervening portion 63. The resonant portion 641 has a body portion 641A and two vibrators 641B.

[0062] The body portion 641A is configured, for example, in a substantially rectangular shape and is the part that is sandwiched between the piezoelectric element 642. The two vibrators 641B extend in the Y direction from both ends of the body portion 641A in the Z direction. The two vibrators 641B have a symmetrical shape, and the free ends of each contact the contact portion 632 (plate-shaped member 633) of the intervening portion 63.

[0063] The piezoelectric element 642 is a vibrating element formed, for example, in the shape of a plate from a ceramic material, and generates vibration when a high-frequency voltage is applied. Two piezoelectric elements 642 are provided, and they are arranged so as to sandwich the body portion 641A of the resonant portion 641 in the X direction.

[0064] The electrode 643 has a clamping portion 643A that clamps the resonant portion 641 and the piezoelectric element 642, and an electrode portion 643B to which a voltage is applied. The electrode portion 643B extends from the clamping portion 643A to the negative side in the Z direction and is connected to the substrate 130. Through the clamping portion 643A and the electrode portion 643B, the electrode 643 applies a voltage to the piezoelectric element 642.

[0065] Two piezoelectric elements 642 are attached to the body portion 641A of the resonant portion 641 and sandwiched between electrodes 643, thereby electrically connecting them to each other. When a voltage is applied to the piezoelectric elements 642 via electrodes 643, vibration is generated.

[0066] The resonant portion 641 has at least two resonant frequencies and deforms in a different manner for each resonant frequency. In other words, the overall shape of the resonant portion 641 is set so that it deforms in a different manner for two resonant frequencies. The different behaviors are the movement of the frame 61 to the positive side in the Y direction and the movement to the negative side via the intervening portion 63.

[0067] As shown in Figure 14, the resonant portion 641 is positioned such that the vibrator 641B faces one of the pair of contact portions 632 of the intervening portion 63. Therefore, when the two vibrators 641B deform, the tips of the vibrators 641B press against the contact portion 632 from the opposing side of each contact portion 632 in a direction inclined with respect to the Y direction (see arrow A).

[0068] When each contact portion 632 is pressed in the direction of arrow A by the tip of the vibrator 641B, a reaction force is generated at each contact portion 632 that tries to return to the vibrator 641B side. In other words, the intervening portion 63 generates a reaction force in the direction from the outside to the inside of the pair of contact portions 632 based on the contact between each vibrator 641B and the pair of contact portions 632.

[0069] The reaction force of the intervening portion 63 to the pressure of the vibrator 641B causes friction between the vibrator 641B and the contact portion 632, generating a thrust in the Y direction in the intervening portion 63. Consequently, a thrust (see arrow B) is applied to the frame 61, which is bonded to the intervening portion 63, causing it to move in the Y direction. As a result, the movable lens connected to the frame 61 moves in the Y direction.

[0070] Furthermore, because the contact portion 632 is configured to extend in the Y direction, the contact portion 632 moves in the Y direction while sliding in contact with the vibrator 641B when pressed by the vibrator 641B. Therefore, since the contact portion 632 is continuously pressed by the vibrator 641B, the frame 61 which is bonded to the intervening portion 63 can be continuously moved in the Y direction. Note that at a certain resonant frequency, the pressing direction of the vibrator 641B is in the direction of arrow A and the sliding direction of the contact portion 632 is in the direction of arrow B, whereas at other resonant frequencies, the pressing direction of the vibrator 641B is in the direction of arrow C and the sliding direction of the contact portion 632 is in the direction of arrow D.

[0071] Such driving operations are performed by each of the ultrasonic motors 64 provided on each of the first walls 111 on both sides in the X direction. In other words, each ultrasonic motor 64 independently drives the second lens unit 32 and the third lens unit 33 in the direction of the optical axis.

[0072] As shown in Figure 15, the detection unit 70 is for detecting the position of the movable lens. The detection unit 70 is provided in the lens drive unit 60 of the second lens unit 32 and the lens drive unit 60 of the third lens unit 33, and is located on the bottom wall 12 of the housing 10.

[0073] The detection unit 70 has a movable electrode 71 and a fixed electrode 72. The movable electrode 71 is an electrode positioned on the movable lens and moves with the movement of the movable lens. The movable electrode 71 is a part of the bottom surface 611A of the holding unit 611 described above. Specifically, the movable electrode 71 corresponding to the second lens unit 32 is the positive side portion of the bottom surface 611A in the X direction with respect to the optical axis O. The movable electrode 71 corresponding to the third lens unit 33 is the negative side portion of the bottom surface 611A in the X direction with respect to the optical axis O.

[0074] The fixed electrode 72 is an electrode positioned on the bottom wall 12 of the housing 10. The fixed electrode 72 is positioned opposite the movable electrode 71 in the Z direction.

[0075] Specifically, the fixed electrode 72 corresponding to the second lens unit 32 is positioned within the range of movement R1 of the second lens unit 32 in the positive side of the bottom wall portion 12 in the X direction relative to the optical axis O. The fixed electrode 72 corresponding to the third lens unit 33 is positioned within the range of movement R2 of the third lens unit 33 in the negative side of the bottom wall portion 12 in the X direction relative to the optical axis O.

[0076] Furthermore, the fixed electrode 72 extends along the Y direction and is configured to have a length corresponding to the stroke (amount of movement) of the corresponding movable lens. In the example shown in Figure 15, the length of the fixed electrode 72 corresponding to the second lens unit 32 in the Y direction is longer than the length of the fixed electrode 72 corresponding to the third lens unit 33 in the Y direction.

[0077] Since the fixed electrode 72 corresponding to the second lens unit 32 and the fixed electrode 72 corresponding to the third lens unit 33 are similar in shape, only the fixed electrode 72 corresponding to the second lens unit 32 will be described in the following explanation. Also, since each lens drive unit 60 is arranged symmetrically in the X and Y directions in this embodiment, the relationship between the positive and negative directions in the fixed electrode 72 corresponding to the third lens unit 33 is the opposite of the relationship between the positive and negative directions in the fixed electrode 72 corresponding to the second lens unit 32.

[0078] Two fixed electrodes 72 are provided side by side in the X direction. Each of the two fixed electrodes 72 has a connecting portion 73 extending toward at least one side in the X direction for connecting to the first portion 131 and the second portion 132 of the substrate 130 described above.

[0079] The two fixed electrodes 72 are configured in a triangular shape, including a hypotenuse that is inclined with respect to the Y direction, and are arranged so that their hypotenuses 721 face each other.

[0080] Specifically, of the two fixed electrodes 72, the positive-side fixed electrode 72A in the X direction has a triangular shape in which the length in the X direction becomes shorter as its position in the Y direction becomes more positive. Of the two fixed electrodes 72, the negative-side fixed electrode 72B in the X direction has a triangular shape in which the length in the X direction becomes longer as its position in the Y direction becomes more positive.

[0081] As described above, each fixed electrode 72 has a different length in the X direction depending on its position in the Y direction. Therefore, as shown in Figures 16A and 16B, for example, the capacitance between the movable electrode 71 and the fixed electrode 72 will differ depending on the position of the movable lens. In other words, the fixed electrode 72 extends along the Y direction such that the capacitance differs depending on the position of the movable lens. To put it another way, the fixed electrode 72 is configured such that the area of ​​the portion facing the movable electrode 71 differs depending on the position of the movable lens.

[0082] The example shown in Figure 16A is an example in which the area of ​​the opposing portion is larger than that shown in Figure 16B. If the fixed electrode 72 is on the positive side in the X direction, the example shown in Figure 16A is an example in which the position of the movable lens in the Y direction is on the negative side than that shown in Figure 16B.

[0083] This allows the capacitance between the movable electrode 71 and the fixed electrode 72 to be varied depending on the position of the movable lens. As a result, the position of the movable lens can be accurately detected based on the capacitance value.

[0084] The capacitance can be measured by applying current to the fixed electrode 72 via the connection portion 73. The movable electrode 71 is also supplied with current via a connection portion (not shown) to the substrate 130.

[0085] Incidentally, in a configuration where the position of the movable lens is detected using a magnet, there is a possibility that the magnetic flux generated from the magnet may leak outside the camera module. Furthermore, it becomes necessary to position the detection unit within the range corresponding to the magnet.

[0086] In contrast, in this embodiment, the position of the movable lens is detected by the change in capacitance, so there is no need to provide a magnet. In other words, in this embodiment, the position of the movable lens can be detected with high accuracy without using a magnet.

[0087] Furthermore, since there is no magnet, there is no need to provide anything on the substrate 130 to detect the magnetic flux of the magnet, thus simplifying the structure of the substrate 130.

[0088] Furthermore, since the fixed electrode 72 extends in the Y direction (the direction of movement of the movable lens), it is possible to create a configuration that corresponds to the stroke of the movable lens. For example, if electrodes of different lengths are provided for each position of the movable lens, it is necessary not only to arrange each electrode individually, but also to connect the wiring of each electrode to the substrate, resulting in a complex configuration that is not suitable for a movable lens with a stroke.

[0089] In contrast, in this embodiment, the fixed electrode 72 extends only in the Y direction, and the position of the movable lens can be detected, thus allowing for a simple configuration and a configuration suitable for a movable lens having a stroke.

[0090] Furthermore, since the fixed electrode 72 is configured to have a shape that includes a hypotenuse inclined with respect to the Y direction (optical axis direction), the shape of the fixed electrode 72 can be simplified. In addition, since the capacitance value detected when the position of the movable lens in the Y direction is continuously changed can be continuously changed, the detection error of the movable lens position can be reduced, and consequently, the detection accuracy of the movable lens position can be improved.

[0091] Furthermore, by providing two fixed electrodes 72, the capacitance corresponding to each of the two fixed electrodes 72 can be detected. As a result, the values ​​of the two capacitances can be compared, which reduces the occurrence of false detections of the movable lens position and, consequently, improves the accuracy of detecting the movable lens position.

[0092] Furthermore, since the two fixed electrodes 72 are positioned so that their hypotenuses 721 face each other, the distance between the two fixed electrodes 72 can be minimized. As a result, the space required for the two fixed electrodes 72 can be reduced, allowing the camera module 1 to be miniaturized.

[0093] By the way, for example, in a configuration where a movable lens is driven by a voice coil motor, the voice coil motor has a magnet that forms part of it, but there is a possibility that the magnetic flux from this magnet may leak to the outside of the camera module.

[0094] In contrast, in this embodiment, the movable lens is driven by the ultrasonic motor 64, so no magnetic flux is generated from the drive unit. Therefore, together with the detection unit 70, the effect of reducing magnetic flux leakage to the outside of the camera module 1 can be further enhanced.

[0095] In the above embodiment, the two fixed electrodes 72 were arranged so that their hypotenuses faced each other. However, the present invention is not limited to this arrangement, and the electrodes do not necessarily have to be arranged so that their hypotenuses face each other.

[0096] Furthermore, in the above embodiment, the fixed electrode 72 was configured to have a shape that includes a hypotenuse inclined with respect to the Y direction, but the present invention is not limited thereto, and the fixed electrode may have a shape that does not include a hypotenuse.

[0097] Furthermore, although two fixed electrodes 72 were provided in the above embodiment, the present invention is not limited thereto, and one fixed electrode may be provided, or three or more fixed electrodes may be provided.

[0098] Furthermore, in the above embodiment, the insertion portion 612 of the frame 61 was inserted through the first guide shaft 51, but the present invention is not limited thereto, and the insertion portion 612 may also be inserted through the second guide shaft 52.

[0099] Furthermore, although the above embodiment provided two types of guide shafts (a first guide shaft and a second guide shaft), the present invention is not limited thereto, and only one type of guide shaft may be provided.

[0100] Furthermore, although the above embodiment had a configuration with two movable lenses composed of a second lens unit 32 and a third lens unit 33, the present invention is not limited thereto, and may have a configuration with at least one or more movable lenses. In this case, at least one lens drive unit may be provided on each of the pair of first walls.

[0101] Furthermore, although the above embodiment had a configuration with four lens units, the present invention is not limited thereto, and any number of lens units may be provided as long as the configuration has at least one movable lens.

[0102] Furthermore, although the above embodiment had a configuration in which the resonant section 641 had two oscillators 641B, the present invention is not limited thereto, and may have, for example, a configuration with one oscillator.

[0103] Furthermore, although the movable part was driven by an ultrasonic motor in the above embodiment, the present invention is not limited thereto, and the movable part may be driven by a drive source other than an ultrasonic motor.

[0104] Furthermore, although the above embodiment provided separate drive control units, reflection drive control units, and imaging control units, the present invention is not limited thereto, and at least two of the drive control units, reflection drive control units, and imaging control units may be composed of a single control unit.

[0105] Furthermore, for example, in the above embodiment, a smartphone, which is a mobile terminal with a camera, was described as an example of a camera-mounted device equipped with a camera module 1. However, the present invention can be applied to a camera-mounted device having a camera module and an image processing unit that processes image information obtained by the camera module. Camera-mounted devices include information equipment and transportation equipment. Information equipment includes, for example, mobile phones with cameras, notebook computers, tablet terminals, portable game consoles, webcams, drones, and in-vehicle devices with cameras (e.g., rearview monitors, drive recorders). Transportation equipment includes, for example, automobiles and drones.

[0106] Figures 17A and 17B show a vehicle V as a camera-mounted device equipped with an in-vehicle camera module VC (Vehicle Camera). Figure 17A is a front view of the vehicle V, and Figure 17B is a rear perspective view of the vehicle V. The vehicle V is equipped with the camera module 1 described in the embodiment as the in-vehicle camera module VC. As shown in Figures 17A and 17B, the in-vehicle camera module VC can be mounted, for example, on the windshield facing forward or on the rear gate facing backward. This in-vehicle camera module VC is used for purposes such as a backup monitor, a drive recorder, collision avoidance control, and autonomous driving control.

[0107] Furthermore, the above embodiments are merely examples of how the present invention may be implemented, and the technical scope of the present invention should not be interpreted as being limited by them. In other words, the present invention can be implemented in various forms without departing from its gist or its main features. For example, the shape, size, number, and material of each part described in the above embodiments are merely examples and can be modified as appropriate.

[0108] The drive device according to the present invention is useful as a drive device, camera module, and camera-mounted device that can accurately detect the position of a movable part without using a magnet.

[0109] All disclosures in the specification, drawings, and abstract contained in the Japanese application No. 2024-230225, filed on December 26, 2024, are incorporated herein by reference.

[0110] 1 Camera module, 10 Housing, 11 Side wall, 12 Bottom wall, 12A Substrate placement section, 20 Reflection drive unit, 21 Reflection housing, 22 Mirror, 23 Reflection drive control unit, 30 Lens unit, 31 First lens unit, 32 Second lens unit, 33 Third lens unit, 34 Fourth lens unit, 40 Imaging unit, 50 Guide unit, 51 First guide axis, 52 Second guide axis, 60 Lens drive unit, 61 Frame, 63 Intervening part, 64 Ultrasonic motor, 70 Detection unit, 71 Movable side electrode, 72 Fixed side electrode, 73 Connection part, 100 Drive control unit, 111 First wall, 111A Placement section, 112 Second wall, 112A Placement section, 112B Opening, 112C first axis support part, 112D second axis support part, 113 third wall, 113A placement part, 113B opening, 113C third axis support part, 113D fourth axis support part, 130 substrate, 131 first part, 132 second part, 133 third part, 200 imaging control part, 611 Holding part, 611A bottom part, 611B side part, 612 inserted part, 613 first contact part, 614 second contact part, 621A fixed part, 631 main body part, 632 contact part, 633 plate member, 641 resonance part, 641A body part, 641B vibrator, 642 Piezoelectric element, 643 electrode, 643A Holding part, 643B electrode part

Claims

1. A drive device comprising: a movable part that can move in the optical axis direction; a housing part that houses the movable part; a drive unit that moves the movable part in the optical axis direction within the housing part; and a detection unit for detecting the position of the movable part, wherein the detection unit includes a movable side electrode disposed on the movable part and a fixed side electrode disposed in the housing part opposite to the movable side electrode, and the fixed side electrode extends along the optical axis direction such that the capacitance between the movable side electrode and the fixed side electrode differs depending on the position of the movable part.

2. The drive device according to claim 1, wherein the fixed electrode is configured such that the area of ​​the portion facing the movable electrode differs depending on the position of the movable portion.

3. The drive device according to claim 2, wherein the fixed electrode is configured to have a shape that includes a hypotenuse inclined with respect to the optical axis direction.

4. The drive device according to claim 3, wherein two fixed electrodes are provided, and the two fixed electrodes are arranged so that their hypotenuses face each other.

5. The drive device according to claim 1, wherein the movable part has a first movable part and a second movable part arranged in the direction of the optical axis, the drive unit has a first drive unit for driving the first movable part and a second drive unit for driving the second movable part, and the detection unit is provided corresponding to the first movable part and the second movable part, respectively.

6. The drive unit comprises an ultrasonic motor having a resonant section composed of a first vibrator and a second vibrator, and an intervening section interposed between the ultrasonic motor and the movable section, which generates a force for moving the movable section based on the vibration of the resonant section, according to claim 1.

7. A camera module comprising: a drive device according to claim 1; an element unit including an optical element held by the movable part; and an imaging unit for capturing an image of a subject formed by the element unit.

8. A camera-mounted device which is an information device or a transport device, comprising: a camera module as described in claim 7; and an imaging control unit for processing image information obtained by the camera module.

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