Anti-shake mechanism, camera module, mobile terminal

Abstract

The present invention provides an image stabilization mechanism that is efficient, consumes little power, is less susceptible to resonance, has a small attitude difference, and is low cost. The image stabilization mechanism includes a base 31, a movable part 32 provided on the base 31 facing the optical axis direction of the camera module 2, the movable part 32 being supported on the base 31 so as to be movable in each of a first direction X perpendicular to the optical axis direction and a second direction Y perpendicular to the optical axis direction and the first direction X, and a drive part 33 that connects the base 31 and the movable part 32 and generates a drive force for moving the movable part 32 in at least one of the first direction X and the second direction Y. The movable part 32 is equipped with an imaging element 32b1, and the driving part 33 has a pair of driving wires 331 that are deformable in the longitudinal direction, one pair facing the first direction X and the other pair facing the second direction Y, both ends of the driving wires 331 are fixed to the base 31, and an intermediate part of the driving wires 331 is attached to the movable part 32. The driving wires are deformed to move the movable part 32 in a direction approaching both ends of the driving wires 331, forming an anti-shake mechanism 3.

Description

Technical Field

[0001] The present invention relates to an anti-shake mechanism built into a camera module provided in a device such as a mobile terminal (e.g., smartphone, tablet), a camera module equipped with the same, and a mobile terminal.

Background Art

[0002] As a conventional technology related to the present invention, for example, the optical image stabilization (OIS) mechanism described in CN108780207A can be mentioned.

[0003] In this conventional technology, a dynamic platform equipped with an image sensor is configured to move in a plurality of directions orthogonal to the optical axis of the camera lens with respect to a static platform. Specifically, the OIS mechanism includes a voice coil motor (VCM). The voice coil motor includes an image sensor frame member as the dynamic platform, a frame of the voice coil motor as the static platform, and a plurality of OIS coils. The OIS coils are mounted on the image sensor frame member within the magnetic field of a magnet so as to generate a force for moving the dynamic platform in a plurality of directions orthogonal to the optical axis of the camera lens.

[0004] The voice coil motor used as a drive source in this configuration has low efficiency and high power consumption. In addition, the combination of the dynamic platform and the static platform in this configuration has problems such as being prone to resonance, having a large posture difference, and high cost.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In view of this, an object of the present invention is to provide an anti-shake mechanism that is superior to the conventional technology, has good efficiency, low power consumption, is difficult to resonate, has a small posture difference, and is low in cost, a camera module equipped with the same, and a mobile terminal.

Means for Solving the Problem

[0006] One aspect of the present invention is an anti-shake mechanism incorporated in a camera module, comprising a base portion, and a movable portion provided opposite to the base portion in the optical axis direction of the camera module. The movable portion is supported by the base portion so as to be movable in each of a first direction orthogonal to the optical axis direction, the optical axis direction, and a second direction orthogonal to the first direction. A driving portion that connects the base portion and the movable portion and generates a driving force for moving the movable portion in at least one of the first direction and the second direction. The movable portion includes an imaging element. The driving portion has a pair of driving wires facing each other in the first direction and a pair of driving wires facing each other in the second direction. Both ends of the driving wires are fixed to the base portion, and an intermediate portion of the driving wires is attached to the movable portion. By deforming at least one of the driving wires in the longitudinal direction, the movable portion is moved in a direction approaching both ends of the driving wires. It is an anti-shake mechanism.

[0007] Further, the driving wire can be one that contracts in the longitudinal direction when heated.

[0008] Further, when one of the driving wires constituting the pair contracts, the other of the driving wires constituting the pair can be extended.

[0009] Further, the driving wire can be formed of metal, but can also be formed of other materials capable of realizing the present invention, and preferably can be formed of a shape memory alloy.

[0010] Further, the base portion includes a power supply electrode, and both ends of the driving wire are fixed to the base portion by being fixed to the power supply electrode and are electrically connected to the power supply electrode. The driving wire can be one that is contracted by self-heating when energized.

[0011] Further, the movable part has a rectangular shape when viewed in the optical axis direction, the movable part includes wire bending parts protruding toward the base part at four corners, and the intermediate part of the drive wire abuts against the side surfaces of the wire bending parts, whereby the intermediate part of the drive wire can be attached to the movable part.

[0012] Further, the wire bending part can be provided with a groove or a protrusion that restricts the drive wire from shifting in the optical axis direction.

[0013] Further, the pair of drive wires facing each other in the first direction are symmetrically arranged in the first direction, the pair of drive wires facing each other in the second direction are symmetrically arranged in the second direction, and the center of the imaging element when viewed in the optical axis direction can coincide with the center positions of the pair of drive wires facing each other in the first direction and the pair of drive wires facing each other in the second direction.

[0014] Further, it can be provided with a vibration detection part that detects vibration applied to the camera module, and a control part that performs control according to the vibration detected by the vibration detection part.

[0015] Further, the control part can cause the drive part to input energy for deforming the drive wire according to the magnitude of the vibration detected by the vibration detection part, and stop the input of the energy when the vibration detection part stops detecting vibration.

[0016] Further, one of the base part and the movable part includes a permanent magnet, and the other includes a Hall element, and the Hall element can detect the positional relationship of the movable part with respect to the base part in at least one of the first direction and the second direction.

[0017] Another form of the present invention is a camera module incorporating the anti-shake mechanism.

[0018] Another form of the present invention is a mobile terminal equipped with the camera module.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Embodiments for Carrying Out the Invention

[0020] Regarding the shake prevention mechanism 3 according to an embodiment of the present invention, it will be described while showing the drawings. Hereinafter, the "optical axis direction" is the optical axis direction of the camera module 2. The subject side is the front (left direction in FIG. 3), and the imaging element 32b1 side is the rear (right direction in FIG. 3).

[0021] The shake prevention mechanism 3 of the present embodiment is incorporated in the camera module 2 provided in a mobile terminal 1 (for example, a smartphone, a tablet) or the like. First, FIGS. 1 and 2 show an outline of the shake prevention function in the mobile terminal 1. Since the shake prevention function itself is well-known, it will be briefly described. As shown in FIG. 1, vibration may be transmitted from a user's hand or the like to the mobile terminal 1 (exemplified by a smartphone). This vibration is transmitted to the camera module 2. The vibration has, for example, a rotational motion component as indicated by an arrow in FIG. 1. Note that it may also have a linear motion component.

[0022] As shown in FIG. 2, a gyro sensor 11 and a servo driver 12 are provided inside the mobile terminal 1, and an actuator 13 and a sensor 14 are provided in the camera module 2. When vibration is transmitted to the camera module 2, the gyro sensor 11 detects it, and the servo driver 12 drives the actuator 13 under the detection of the sensor 14 and loops it (servo loop), so that the image captured by the lens and projected onto the imaging element 32b1 can be made non-blurred.

[0023] FIG. 3 schematically shows the configuration of the camera module 2. A lens support portion 21 is supported by the mobile terminal 1. Although not shown, the lens support portion 21 is provided with a lens, a diaphragm, and an autofocus mechanism. An imaging element 32b1 that receives the imaging light formed after passing through the lens is provided behind the lens support portion 21 in the optical axis direction. This imaging element 32b1 is provided in the shake prevention mechanism 3.

[0024] The anti-shake mechanism 3 includes a base 31, a movable part 32, and a drive part 33. The base 31 is a plate-shaped part fixedly provided in the anti-shake mechanism 3 (and the camera module 2). As shown in FIG. 7B, the base 31 includes a rigid flat base plate 311 and a flexible printed circuit (FPC) 312 bonded to the front surface of the base plate 311 and flexible compared to the base plate 311 (see FIGS. 8A and 8B). The base plate 311 has a rectangular shape (specifically, a rectangular shape) when viewed in the optical axis direction. The portion of the flexible substrate 312 that overlaps the base plate 311 has the same shape as the base plate 311. The base 31 includes a power supply electrode 313. The power supply electrode 313 is fixed to the base plate 311 so as to protrude forward in the optical axis direction. A rectangular wave-shaped current is supplied to the power supply electrode 313 from the outside of the anti-shake mechanism 3 in the camera module 2. Note that the supplied current may be a direct current or a current having a waveform other than a rectangular wave.

[0025] The movable part 32 is a plate-shaped part provided opposite to the base 31 in the optical axis direction. The movable part 32 includes a flat base plate 321. The base plate 321 has a rectangular shape (specifically, a rectangular shape) when viewed in the optical axis direction. As shown in FIGS. 7A and 7B, the movable part 32 includes a movable mechanism part 32a and an imaging part 32b that is separate from the movable mechanism part 32a and is integrated with the movable mechanism part 32a by being attached to the movable mechanism part 32a by adhesion, for example. The imaging part 32b includes an imaging element 32b1.

[0026] The movable part 32 is supported by the base 31 so as to be movable in each of a first direction X orthogonal to the optical axis direction, the optical axis direction, and a second direction Y orthogonal to the first direction X. Here, in the description of the present embodiment, the left-right direction shown in FIG. 4 is defined as the first direction X, and the up-down direction is defined as the second direction Y. Note that the movable part 32 can also move in a direction (an oblique direction in FIG. 4, and the angle is arbitrary) in which the first direction X and the second direction Y are combined.

[0027] As shown in FIGS. 9A and 9B, the movable part 32 is provided with wire bending parts 322 protruding rearward (toward the base part 31) from the base plate 321 at the four corners. That is, in the movable part 32, the wire bending parts 322 are provided at four positions. The wire bending part 322 of the present embodiment is a columnar protrusion protruding from the rear surface of the base plate 321. The wire bending part 322 is formed of an insulator such as resin. The drive wire 331 is hooked on the curved side surface of the wire bending part 322. Specifically, as shown in FIG. 4, the drive wire 331 is hooked along a part of the outer part 322a facing the outside of each wire bending part 322 with reference to the virtual quadrilateral formed by the four wire bending parts 322. Thereby, the drive wire 331 is bent in the optical axis direction view. In the present embodiment, as shown in FIG. 4, the drive wire 331 is bent at an acute angle, but it may be bent at a right angle or an obtuse angle. The wire bending part 322 is provided with a groove 3221 that restricts the drive wire 331 from shifting in the optical axis direction (see FIG. 9A). This groove 3221 is provided on the side surface of the wire bending part 322 so as to be orthogonal to the axial direction of the columnar wire bending part 322. Note that instead of the groove 3221, a protrusion for hooking the drive wire 331 may be provided. Also, the entire outer peripheral surface of the wire bending part 322 may be a curved surface, and the drive wire 331 may be hooked on the recessed part of the curved surface.

[0028] A rotating part 323 is provided at the axial end of the wire bending part 322. The rotating part 323 includes a rotating body (specifically, a ball) embedded so that a part protrudes from the end surface of the wire bending part 322 facing the base part 31. The rotating part 323 is in contact with the front surface (flat surface) of the base part 31 and rotates with respect to the front surface of the base part 31. Thereby, while the movable part 32 keeps the distance from the base part 31 constant, it moves in the plane direction orthogonal to the optical axis direction.

[0029] The base 31 and the movable part 32 are held in position in the optical axis direction while allowing movement in the plane direction so as not to separate in the optical axis direction. Specifically, they are held in position in the optical axis direction by the attractive force of magnetic force between a plurality (four in this embodiment) of permanent magnets 324 provided on the rear surface of the movable part 32 and a magnetic body 314 (for example, a steel material) provided on the front surface of the base 31 at a position facing the plurality of permanent magnets 324. The attractive force between the permanent magnet 324 and the magnetic body 314 is set to act even when the movable part 32 is displaced to the maximum extent with respect to the base 31. Also, although not shown, the base 31 and the movable part 32 are held in position in the plane direction by providing a stopper or the like that abuts on the movable part 32 in order to restrict movement beyond the driving range of the driving part 33 in the plane direction.

[0030] As shown in FIG. 9B, a columnar wire guide 325 is provided on the movable part 32 in addition to the wire bending part 322. This wire guide 325 protrudes rearward from the base plate 321 of the movable part 32. The wire guide 325 is formed of an insulator such as resin. As shown in FIG. 4 and FIG. 5 in which a partial configuration is extracted from FIG. 4, this wire guide 325 is located between the power supply electrode 313 and the wire bending part 322 (the one closest to the power supply electrode 313 on the path) in the path through which each driving wire 331 passes. On the outer peripheral surface of the wire guide 325, a pair of each driving wire 331 facing in the first direction X (in a combination of two driving wires 331 shown in FIG. 5 and a driving wire 331 (not shown) that is symmetric about the left and right) abuts. For this reason, two wire guides 325 are provided facing in the second direction Y. The contact state between the outer peripheral surface of the wire guide 325 and each driving wire 331 changes according to the expansion and contraction of each driving wire 331 and the movement of the movable part 32 with respect to the base 31. The wire guide 325 suppresses the deviation of each driving wire 331 in a direction intersecting the extending direction between the power supply electrode 313 and the wire bending part 322.

[0031] Here, in the present embodiment, for convenience of arrangement, a columnar wire guide 315 is also provided on the base 31. This wire guide 315 protrudes forward from the base plate 311 of the base 31. The wire guide 315 is formed of an insulator such as resin. The wire guide 315 passes through a through hole 315h provided in the flexible substrate 312 shown in FIG. 8A. As shown in FIG. 4 and FIG. 6 which extracts a partial configuration from FIG. 4, this wire guide 315 is located between the power supply electrode 313 and the wire bending portion 322 (the one closest to the power supply electrode 313 on the above path) in the path through which each drive wire 331 passes. On the outer peripheral surface of the wire guide 315, each of a pair (two) of drive wires 331 that face each other in the second direction Y abuts. For this reason, two wire guides 315 are provided facing each other in the first direction X. The contact state between the outer peripheral surface of the wire guide 315 and each drive wire 331 changes according to the expansion and contraction of each drive wire 331. Similar to the wire guide 325 of the movable portion 32, this wire guide 315 suppresses the deviation of each drive wire 331 in the direction intersecting the extending direction between the power supply electrode 313 and the wire bending portion 322.

[0032] One of the base 31 and the movable part 32 (the movable part 32 in this embodiment) is provided with a permanent magnet 324, and the other (the base 31 on the fixed side in the anti-shake mechanism 3 in this embodiment) is provided with a Hall element 316. As shown in FIGS. 8A and 8B, the Hall element 316 is one set (the upper magnetic body 314 in FIG. 8A) of a pair (two) of magnetic bodies 314 extending in the first direction X and one set (the left magnetic body 314 in FIG. 8A) of a pair (two) of magnetic bodies 314 extending in the second direction Y, and is provided so as to be sandwiched between two magnetic bodies 314 arranged in each direction. By detecting the magnetism emitted by the permanent magnet 324 provided at a position facing the magnetic body 314 with this Hall element 316, the positional relationship between the movable part 32 and the base 31 in the first direction X and the second direction Y is detected. Since the Hall element 316 is provided so as to be sandwiched between two magnetic bodies 314 arranged in each direction in this way, the position holding in the optical axis direction between the base 31 and the movable part 32 due to the attractive force (magnetic force) between the permanent magnet 324 and the magnetic body 314 and the detection of the positional relationship between the movable part 32 and the base 31 can be performed in the same part.

[0033] The drive unit 33 is a part that connects the base 31 and the movable part 32 and generates a driving force for moving the movable part 32 in at least one of the first direction X and the second direction Y. As shown in FIG. 4, the drive unit 33 has a pair (two) of drive wires 331 facing the first direction X and a pair (two) of drive wires 331 facing the second direction Y. That is, four drive wires 331 are used. The drive wire 331 is configured to be deformable (stretchable) in the length direction. Specifically, the drive wire 331 contracts in the length direction when heated, and in this embodiment, it is formed of a shape memory alloy (SMA). The plurality of drive wires 331 are arranged with a shift in the front-rear direction in the optical axis direction. For this reason, they do not interfere with each other as they expand and contract. At least the portions where the drive wires 331 cross each other and the surrounding areas as shown in FIG. 4 in the view of the optical axis direction only need to be arranged with a shift in the front-rear direction. Since the drive wire 331 is thin, even if it is arranged with a shift in the optical axis direction, it hardly affects the dimension of the hand shake prevention mechanism 3 in the optical axis direction. The drive wire 331 is, for example, a linear wire having a circular cross section. Such a shape memory alloy wire is advantageous in terms of cost because general-purpose products are easily available. The thickness of the drive wire 331 is constant over the length direction. Also, the material is homogeneous over the length direction. The cross-sectional dimension can be set variously, for example, it can be set to a diameter of 50 μm. The cross-sectional dimension can be determined in consideration of the required length from one end to the other end of the drive wire 331, the reaction accuracy of expansion and contraction, durability, etc. When the heating of the drive wire 331 stops, it returns to its original length by natural cooling. That is, when the heating stops, it elongates in the length direction. This elongation is also caused by an external force being applied to the drive wire 331. The external force is, for example, the tensile force generated when another one of the pair (two) of drive wires 331 contracts.

[0034] Both ends of the drive wire 331 (specifically, both ends of the portion of the drive wire 331 where the driving force is generated) are fixed to the base 31 (power supply electrode 313), and the middle portion of the drive wire 331 is attached to the movable portion 32 so as to be displaceable by being hooked on the wire bending portion 322. The tension of the drive wire 331 in the free state (not in the contracted state and the extended state) is set so that no slack occurs. By keeping the drive wire 331 in a stretched state in the free state, the sensitivity of the reaction can be ensured. The tension can be set in consideration of the temperature change assumed during the use of the mobile terminal 1.

[0035] As shown in FIG. 4, a pair (two) of drive wires 331 facing each other in the first direction X are symmetrically arranged in the first direction X, and a pair (two) of drive wires 331 facing each other in the second direction Y are symmetrically arranged in the second direction Y. The center of the optical axis direction view of the imaging element 32b1 (the position where the diagonals intersect in a rectangle or a square) is arranged to coincide with the center positions of a pair of drive wires 331 facing each other in the first direction X and a pair of drive wires 331 facing each other in the second direction Y. By deforming at least one of the drive wires 331 (specifically, by heating the drive wire 331 to contract it), the movable portion 32 can be moved in a direction approaching both ends of the drive wire 331.

[0036] In this embodiment, the heating of the drive wire 331 is performed by utilizing the resistive heat generated by energizing the drive wire 331 itself. For this reason, both ends of the drive wire 331 are electrically connected to the power supply electrodes 313 in the base 31. The connection of the drive wire 331 to the power supply electrodes 313 may be made by physical coupling such as tying, clamping, screwing, etc., or may be made by adhesion using solder or a conductive adhesive. Among the power supply electrodes 313, the side to which one end side of the drive wire 331 is fixed is the positive electrode, and the side to which the other end side is fixed is the negative electrode. Further, the middle portion of the drive wire 331 abuts against the side surface of the wire bending portion 322. The drive wire 331 contracts by self-heating due to the current supplied from the power supply electrodes 313. Therefore, in this embodiment, the contraction of the drive wire 331 is not partial but is performed over the entire length. When one of the pair (two) of drive wires 331 facing each of the directions X and Y contracts due to energization, the other one is in a non-heated state because it is not energized and does not contract or expand spontaneously. However, the other drive wire 331 is extended by the elasticity of the other drive wire 331 itself by receiving the force accompanying the contraction of one drive wire 331. To specifically explain the action, one drive wire 331 that is energized and contracts transmits a driving force to the wire bending portion 322 to which the drive wire 331 is hooked. Along with this, the movable portion 32 moves. As a result, the other drive wire 331 (non-energized) hooked to another wire bending portion 322 provided in the moving movable portion 32 is forcibly extended. Thus, in this embodiment, when one of the drive wires 331 constituting a pair contracts, the other of the drive wires 331 constituting the pair is configured to extend. Thereby, the driving force generated by one of the drive wires 331 is not inhibited by the other of the drive wires 331. Further, since one of the drive wires 331 contracts while the tension of the other of the drive wires 331 is applied to the movable portion 32, the movable portion 32 can be stably moved. Here, in terms of appearance, since the pair of drive wires 331 (two each) facing each of the directions X and Y are in a relationship where one (one) contracts and the other (one) extends, they seem to be interlocked.

[0037] Of the pair (two) of drive wires 331 facing the first direction X (the left - right direction in the figure) shown in FIG. 4, one is extracted for easier explanation and shown in FIG. 5. Among the pair (two) of drive wires 331 facing the first direction X, those in a positional relationship opposite to the one shown in FIG. 5 perform an operation that is symmetric by 180° (left - right reversed operation in the figure) when viewed in the optical axis direction with respect to the one shown in the figure. As described above, the pair (two) of drive wires 331 are controlled such that when one of them contracts, the other does not contract, and at the same time, the contraction forces of both (two) do not oppose each other. Also, of the pair (two) of drive wires 331 facing the second direction Y (the up - down direction in the figure), one is extracted for easier explanation and shown in FIG. 6. Among the pair (two) of drive wires 331 facing the second direction Y, those in a positional relationship opposite to the one shown in FIG. 6 perform an operation that is symmetric by 180° (up - down reversed operation in the figure) when viewed in the optical axis direction with respect to the one shown in the figure. Each of the pair of drive wires 331 facing the second direction Y performs an operation that is symmetric by 90° (see FIG. 6) when viewed in the optical axis direction with respect to the one shown in FIG. 5. For this reason, the following detailed explanation will be made only with respect to FIG. 5.

[0038] One of the pair of drive wires 331 shown in Fig. 5, in the illustrated positional relationship, first, as the first path 331a, extends obliquely upward to the right from the upper left power supply electrode 313 through the upper wire guide 325 to the upper right wire bending portion 322. At the upper right wire bending portion 322, the drive wire 331 is bent downward and, as the second path 331b, extends downward (vertically downward) to the lower right wire bending portion 322. At the lower right wire bending portion 322, the drive wire 331 is bent to the left. Next, as the third path 331c, it extends obliquely upward to the left from the lower right wire bending portion 322 through the lower wire guide 325 to the lower left power supply electrode 313. Thus, the path through which the drive wire 331 of the present embodiment passes (the continuous first path 331a to the third path 331c) is substantially trapezoidal in shape (the first path 331a and the third path 331c corresponding to the "legs" are symmetric), the wire bending portion 322 is at the intersection of the "lower base" of the trapezoid (corresponding to the second path 331b) and the "legs", and the drive wire 331 is arranged along each side of the portion excluding the "upper base" of the trapezoid. Note that the drive wire 331 does not necessarily need to be arranged along all sides of the trapezoid (strict trapezoidal shape). For example, at the wire bending portion 322, since the drive wire 331 is curved, it is arranged away from the sides of the trapezoid.

[0039] When the drive wire 331 is energized, the entire drive wire 331 contracts in the longitudinal direction. As a result, in the upper and lower paths (the first path 331a and the third path 331c) shown in the figure, along each path, the drive wire 331 as a whole moves in the left direction (specifically, the first path 331a is in the lower left diagonal direction, and the third path 331c is in the upper left diagonal direction) among the arrows shown in the figure. Also in the path (the second path 331b) on the right side of the figure, the drive wire 331 as a whole moves as this path contracts. Since the power supply electrode 313 is provided on the fixed base 31, the upper and lower wire bending portions 322 shown in the figure provided on the movable part 32 move in the left direction shown in the figure. Therefore, the movable part 32 moves in the left direction of the arrow drawn in the center of FIG. 5. On the other hand, when the energization of the drive wire 331 stops, the entire drive wire 331 extends in the longitudinal direction by natural cooling. At the same time, among the pair, the other drive wire 331 not shown in FIG. 5 contracts by its own tension (it can also be contracted by energization). Along with this, contrary to the case during energization, the movable part 32 moves in the right direction of the arrow drawn in the center of FIG. 5.

[0040] The first path 331a and the third path 331c are symmetrically arranged with respect to a virtual line (not shown) along the first direction X. Therefore, the first path 331a and the third path 331c have the same length and the same angle with respect to the virtual line in the optical axis direction view. Also, the angle formed by the first path 331a and the second path 331b is equal to the angle formed by the second path 331b and the third path 331c. With each path arranged in this way, when the entire drive wire 331 contracts, the two wire bending portions 322 located above and below the figure, which the drive wire 331 is hooked on, move the same distance along the virtual line. For this reason, the base plate 321 provided with the wire bending portion 322 also moves the same distance.

[0041] In this embodiment, as shown in FIG. 4, four drive wires 331 are arranged. When moving the movable part 32 in the first direction X, one of the pair (two) of drive wires 331 facing the first direction X is energized, and the other one is de-energized. Further, when moving the movable part 32 in the second direction Y, one of the pair (two) of drive wires 331 facing the second direction Y is energized, and the other one is de-energized. The drive wire 331 on the first direction X side and the drive wire 331 on the second direction Y side may be energized simultaneously. In this case, the movable part 32 can be moved in an oblique direction. By providing a difference in the current supplied to the drive wire 331 on the first direction X side and the drive wire 331 on the second direction Y side, the moving angle with respect to the first direction X or the second direction Y can be adjusted.

[0042] Here, as a comparative example, two diagonal points in a movable part formed in a square shape when viewed in the optical axis direction are set as fixed points, and the other two diagonal points are set as operating points. A configuration is provided in which the operating points are moved in one direction along the periphery of the movable part and in another direction orthogonal to the one direction by drive wires made of a shape memory alloy. In this comparative example, four drive wires extending linearly along the periphery of the movable part are arranged. However, in this comparative example, in order to move the movable part in a desired direction, it is necessary to move two operating points, and for this purpose, the energization control (on, off) of the four drive wires becomes complicated.

[0043] On the other hand, in this embodiment, by selecting and energizing one of the pair (two) of drive wires 331 facing the first direction X and one of the pair (two) of drive wires 331 facing the second direction Y, or by energizing only one of the pair of drive wires 331 facing the first direction X, or by energizing only one of the pair of drive wires 331 facing the second direction Y, the movable part 32 can be moved in a desired direction. Therefore, a high-performance anti-shake mechanism 3 can be realized with a simple configuration that is cost-effective. And in this embodiment, by using the drive wire 331 as a drive source, the anti-shake mechanism 3 can be made less likely to resonate compared to the conventional case, the posture difference becomes smaller, and the cost can be reduced.

[0044] Next, the camera module 2, or a device (mobile terminal 1) equipped with the camera module 2, includes a vibration detection unit that detects vibrations applied to the camera module 2, and a control unit (not shown) that performs control in response to the vibrations detected by the vibration detection unit. Note that, in order to control the shake prevention mechanism 3 corresponding to the camera shake of the camera module 2 in the mobile terminal 1, a configuration for control (for example, a control unit and sensors not specifically described in this description) can utilize a known configuration. For the vibration detection unit, for example, the gyro sensor 11 described above (see FIG. 1) is used. The control unit causes the drive unit 33 to input energy (energization in this embodiment) for heating the drive wire 331 according to the magnitude of the vibration detected by the vibration detection unit, and stops the input of energy when the vibration detection unit no longer detects vibrations.

[0045] By the control unit controlling in consideration of the time difference from the energization, which is the input to the drive wire 331, to the contraction, which is the output, the responsiveness to the vibrations applied to the camera module 2 due to camera shake can be improved. Further, by the control unit instantaneously switching the energization of one of the pair of drive wires 331 facing each other in the X and Y directions and the energization of the other, a sensitive movement of the movable part 32 with respect to the base part 31 can be realized. By the above control, it is possible to respond to the camera shake of the camera module 2 so as not to affect the imaging element 32b1.

[0046] Summarizing the above-described embodiment, the present embodiment is an anti-shake mechanism 3 incorporated in the camera module 2, which includes a base 31 and a movable part 32 provided to face the base 31 in the optical axis direction of the camera module 2. The movable part 32 is supported by the base 31 so as to be movable in each of a first direction X orthogonal to the optical axis direction, the optical axis direction, and a second direction Y orthogonal to the first direction X and the optical axis direction. A driving part 33 is provided to connect the base 31 and the movable part 32 and generate a driving force for moving the movable part 32 in at least one of the first direction X and the second direction Y. The movable part 32 includes an imaging element 32b1. The driving part 33 has a pair of driving wires 331 facing each other in the first direction X and a pair of driving wires 331 facing each other in the second direction Y. Both ends of the driving wire 331 are fixed to the base 31, and an intermediate part of the driving wire 331 is attached to the movable part 32. By deforming at least one of the driving wires 331 in the longitudinal direction, the movable part 32 is moved in a direction approaching both ends of the driving wire 331. This is the anti-shake mechanism 3.

[0047] According to this configuration, by deforming at least one of the pair of driving wires 331 made of shape memory alloy provided to face each of the directions X and Y, the movable part 32 provided with the imaging element 32b1 can be moved relative to the base 31.

[0048] Also, the driving wire 331 can be configured to contract in the longitudinal direction when heated.

[0049] According to this configuration, the contraction force of the driving wire 331 can be utilized as a force for moving the movable part 32 relative to the base 31.

[0050] Also, when one of the pair of driving wires 331 constituting the pair contracts, the other of the pair of driving wires 331 can be configured to elongate.

[0051] According to this configuration, the driving force generated by one of the driving wires 331 is not inhibited by the other of the driving wires 331.

[0052] Further, the drive wire 331 can be formed of a shape memory alloy.

[0053] According to this configuration, the drive wire 331 can be formed of a material that is easily available.

[0054] Further, the base 31 includes a power supply electrode 313, and both ends of the drive wire 331 are fixed to the base 31 by being fixed to the power supply electrode 313 and are electrically connected to the power supply electrode 313. The drive wire 331 can be configured to contract by self-heating when energized.

[0055] According to this configuration, since the drive wire 331 contracts by self-heating when energized, a separate heating means for heating the drive wire 331 is unnecessary.

[0056] Further, the movable part 32 has a rectangular shape when viewed in the optical axis direction, and the movable part 32 includes wire bending parts 322 protruding toward the base 31 at four corners. The intermediate part of the drive wire 331 is attached to the movable part 32 by contacting the side surface of the wire bending part 322.

[0057] According to this configuration, a pair of drive wires 331 facing each other in the X and Y directions can be easily configured by the wire bending parts 322 provided at the four corners of the movable part 32.

[0058] Further, the wire bending part 322 can be provided with a groove or a protrusion that restricts the drive wire 331 from shifting in the optical axis direction.

[0059] According to this configuration, the wire bending part 322 can stably hold the drive wire 331 in the optical axis direction by the groove or the protrusion.

[0060] In addition, the pair of drive wires 331 facing the first direction X are symmetrically arranged in the first direction X, the pair of drive wires 331 facing the second direction Y are symmetrically arranged in the second direction Y, and the center of the imaging element 32b1 in the optical axis direction view can coincide with the center positions of the pair of drive wires 331 facing the first direction X and the pair of drive wires 331 facing the second direction Y.

[0061] According to this configuration, all the drive wires 331 are symmetrically arranged, and by positioning the center of the imaging element 32b1 at the center position in the arrangement, the configuration of the anti-shake mechanism 3 can be simplified.

[0062] In addition, it can be provided with a vibration detection unit (such as the gyro sensor 11) that detects vibrations applied to the camera module 2, and a control unit that performs control according to the vibrations detected by the vibration detection unit.

[0063] According to this configuration, by the control unit performing control according to the vibrations detected by the vibration detection unit, a high-performance anti-shake mechanism 3 can be achieved.

[0064] In addition, the control unit can cause the drive unit 33 to input energy for deforming the drive wire 331 according to the magnitude of the vibration detected by the vibration detection unit, and stop the input of the energy when the vibration detection unit stops detecting vibrations.

[0065] According to this configuration, by the control unit controlling the input of energy to the drive unit 33, a high-performance anti-shake mechanism 3 can be achieved.

[0066] In addition, one of the base 31 and the movable part 32 is provided with a permanent magnet 324, and the other is provided with a Hall element 316. The Hall element 316 can detect the positional relationship of the movable part 32 with respect to the base 31 in at least one of the first direction and the second direction.

[0067] According to this configuration, the combination of the permanent magnet 324 and the Hall element 316 can simplify the configuration for detecting the moving state of the movable part 32.

[0068] Further, the present embodiment is the camera module 2 incorporating the shake prevention mechanism, and is the mobile terminal 1 including the camera module 2.

[0069] According to the present embodiment configured as described above, the movable part 32 provided with the imaging element 32b1 can be moved relative to the base part 31 by the pair of drive wires 331 provided to face each other in the X and Y directions. Therefore, it is superior to the prior art, and can provide a shake prevention mechanism 3 that is efficient, has low power consumption, does not cause resonance, and has low cost, a camera module 2 incorporating the same, and a mobile terminal 1.

[0070] Although the present embodiment is as described above, the present invention is not limited to the above-described form, and can be appropriately modified within the scope intended by the present invention. Also, the effects of the present invention are not limited to those described in the above embodiment. That is, the disclosed embodiment is illustrative in all respects and does not limit the present invention. The scope of the present invention is defined by the claims rather than the foregoing description. Also, it is intended that the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

[0071] For example, in the above embodiment, the drive wire 331 is configured to contract by self-heating due to the current supplied from the power supply electrode 313. However, it is not limited to this, and another heat source may be provided separately from the drive wire 331. In this case, the power supply electrode 313 is unnecessary, and both ends of the drive wire 331 are fixed to another position of the base part 31.

[0072] Also, in the above embodiment, both ends of the drive wire 331 are fixed to the base part 31, and the intermediate part of the drive wire 331 is attached to the movable part 32. However, conversely, a configuration in which both ends of the drive wire 331 are fixed to the movable part 32 and the intermediate part of the drive wire 331 is attached to the base part 31 may be used.

[0073] Also, although the wire bending portion 322 in the above embodiment was a columnar protrusion, it can also be implemented by a pulley that rotates as the drive wire 331 expands and contracts.

[0074] Also, in the above embodiment, four drive wires 331 were used. However, the number of drive wires 331 included in the hand shake prevention mechanism 3 is not limited. Therefore, three or five or more may be used. It is desirable to arrange each of the plurality of drive wires 331 at rotationally symmetric positions in order to facilitate control.

[0075] Also, grooves through which the drive wire 331 passes may be formed in the wire guides 315 and 325, and the drive wire 331 may be positioned with respect to the wire guides 315 and 325 by these grooves.

Explanation of Reference Numerals

[0076] 1 Mobile terminal 2 Camera module 3 Hand shake prevention mechanism 31 Base 311 Base plate (base) 312 Flexible printed circuit board (FPC) 313 Power supply electrode 314 Magnetic body 315 Wire guide 316 Hall element 32 Movable part 32a Movable mechanism part 32b Imaging part 32b1 Image sensor 321 Base plate (movable part) 322 Wire bending portion 323 Rotating part 324 Permanent magnet 33 Driving part 331 Drive wire X First direction Y Second direction

Claims

1. An anti-shake mechanism incorporated in a camera module, comprising: a base; a movable part provided opposite to the base in the optical axis direction of the camera module, the movable part being supported so as to be movable in each of a first direction orthogonal to the optical axis direction, the optical axis direction, and a second direction orthogonal to the first direction with respect to the base; a driving part that connects the base and the movable part and generates a driving force for moving the movable part in at least one of the first direction and the second direction; the movable part includes an imaging element; the driving part has a pair of driving wires facing each other in the first direction and a pair of driving wires facing each other in the second direction; both ends of the driving wire are fixed to the base, and an intermediate part of the driving wire is attached to the movable part; by deforming at least one of the driving wires in the longitudinal direction, the movable part is moved in a direction approaching both ends of the driving wire; an anti-shake mechanism, wherein two first wire guides protruding toward the base are provided on the movable part so as to face each other in the second direction, and each driving wire of the pair facing each other in the first direction abuts against an outer peripheral surface of the two first wire guides.

2. the driving wire contracts in the longitudinal direction when heated; when one of the driving wires constituting the pair contracts, the other of the driving wires constituting the pair elongates; the driving wire is formed of a shape memory alloy. The anti-shake mechanism according to claim 1.

3. The anti-shake mechanism according to claim 1, wherein two second wire guides protruding toward the movable part are provided on the base so as to face each other in the first direction, and each driving wire of the pair facing each other in the second direction abuts against an outer peripheral surface of the two second wire guides.

4. the base includes a power supply electrode, and both ends of the driving wire are fixed to the base by being fixed to the power supply electrode and are electrically connected to the power supply electrode; the driving wire is contracted by self-heating when energized. The anti-shake mechanism according to claim 2.

5. the movable part has a rectangular shape when viewed in the optical axis direction; the movable part includes wire bending parts protruding toward the base at four corners. On the side surface of the wire bending portion, the intermediate portion of the drive wire abuts, so that the intermediate portion of the drive wire is attached to the movable portion. The anti-shake mechanism according to claim 1.

6. The wire bending portion includes a groove or a protrusion that restricts the drive wire from shifting in the optical axis direction. The anti-shake mechanism according to claim 5.

7. A rotating portion is provided at an axial end of the wire bending portion. The rotating portion includes a rotating body embedded so that a part thereof protrudes from an end surface facing the base portion of the wire bending portion. The rotating portion is in contact with the surface of the base portion and rotates with respect to the surface of the base portion. The anti-shake mechanism according to claim 5.

8. The pair of drive wires facing each other in the first direction are symmetrically arranged in the first direction. The pair of drive wires facing each other in the second direction are symmetrically arranged in the second direction. At the center positions of the pair of drive wires facing each other in the first direction and the pair of drive wires facing each other in the second direction, the center in the optical axis direction view of the imaging element coincides. The anti-shake mechanism according to claim 1.

9. A vibration detection unit that detects vibrations applied to the camera module. A control unit that performs control according to the vibrations detected by the vibration detection unit. The anti-shake mechanism according to claim 1.

10. The control unit causes the drive unit to input energy for deforming the drive wire according to the magnitude of the vibrations detected by the vibration detection unit, and stops the input of the energy when the vibration detection unit stops detecting vibrations. The anti-shake mechanism according to claim 9.

11. One of the base portion and the movable portion includes a permanent magnet, and the other includes a Hall element. The Hall element detects the positional relationship of the movable portion with respect to the base portion in at least one of the first direction and the second direction. The anti-shake mechanism according to claim 1.

12. A camera module incorporating the anti-shake mechanism according to any one of claims 1 to 11.

13. A mobile terminal including the camera module according to claim 12.

Images