Camera actuator

Abstract

A camera actuator comprises: a fixed frame; a first movable frame, which can move in a first direction relative to the fixed frame; a second movable frame, which can move in a second direction orthogonal to the first direction relative to the first movable frame; a lens unit, which can move in a third direction orthogonal to the first direction and the second direction relative to the second movable frame; a first driving part, which moves the first movable frame in the first direction; a second driving part, which moves the second movable frame in the second direction; and a third driving part, which moves the lens unit in the third direction; the third driving part comprises: a driving source part, which is composed of a first piezoelectric element and a second piezoelectric element that are extended by electricity and are bonded in a direction orthogonal to the extension direction; and an abutting part, which abuts against the lens unit and moves in a manner describing an elliptical trajectory according to the deformation of the driving source part.

Description

Technical Field

[0001] The present invention relates to a camera actuator, which is applied to a camera module mounted on electronic devices (information devices) such as smartphones. The actuator has an automatic focusing function and is used to move a camera lens to correct shake. Background Art

[0002] As an example of prior art, the lens holder drive device described in Japanese Patent Application Laid-Open No. 2012-58762 is cited. This lens holder drive device includes an autofocus area and a shake correction area located within the autofocus area. The autofocus area includes a lens holder with a coil, four magnets, and two leaf springs. The shake correction area includes a base substrate, four cables, and four substrates with coils. Summary of the Invention

[0003] Problems to be solved by the invention

[0004] Because the autofocus area in this prior art is held in place by two leaf springs, it is prone to resonance. Furthermore, the autofocus area and the shake correction area are connected by four cables, making the shake correction area susceptible to resonance. Furthermore, this prior art requires the placement of a shake correction coil adjacent to the magnet in the autofocus area, which inevitably increases the size of the lens holder drive device.

[0005] In view of the above, an object of the present invention is to provide a small camera actuator having an autofocus function and a shake correction function.

[0006] Solutions for solving problems

[0007] The present invention is a camera actuator, which comprises: a fixed frame; a first movable frame, which is supported by the fixed frame on the inside and can move relative to the fixed frame in a first direction; a second movable frame, which is supported by the first movable frame on the inside and can move relative to the first movable frame in a second direction orthogonal to the first direction; a lens unit, which is supported by the second movable frame on the inside and can move relative to the second movable frame in a third direction orthogonal to the first direction and the second direction respectively; a first driving part, which is continuously provided on the fixed frame and the first movable frame and has a piezoelectric element that is extended by energization element, causing the first movable frame to move in the first direction; a second driving unit, which is continuously provided on the first movable frame and the second movable frame and has a piezoelectric element that is extended by power supply, causing the second movable frame to move in the second direction; and a third driving unit, which is fixed to the second movable frame, causing the lens unit to move in the third direction; the third driving unit comprises: a driving source unit, which is composed of a first piezoelectric element that is extended by power supply and a second piezoelectric element that are attached in a direction perpendicular to the extension direction; and an abutting unit, which abuts against the lens unit and moves in a manner describing an elliptical trajectory according to the deformation of the driving source unit.

[0008] In addition, the second moving frame is a polygonal frame, and the third driving unit can extend along one side of the polygonal shape of the second moving frame.

[0009] Furthermore, the third driving unit may be provided along one side of the polygonal shape of the second moving frame, the side being neither a side close to the first driving unit nor a side close to the second driving unit.

[0010] In addition, the second movable frame is a rectangular or square frame, and the lens unit can move in the third direction using a rolling body arranged between it and the second movable frame. The rolling body can be located at a position closer to the end side than the center of one side of the rectangular or square shape.

[0011] In addition, the rolling bodies are arranged in groups of two, and the rolling bodies in a group can be respectively arranged at positions symmetrically rotated by 180° in the second movable frame.

[0012] In addition, the first driving unit and the second driving unit can respectively include: a driving force generating unit, which has a piezoelectric element that is extended and compressed by energization; a rod-shaped unit, which is adjacent to one side of the extension direction and the shortening direction of the piezoelectric unit and extends along the extension direction and the shortening direction; and a weight unit, which is adjacent to the other side of the extension direction and the shortening direction of the driving force generating unit.

[0013] In addition, the driving force generating portion is composed of a piezoelectric element that extends and contracts by being energized. When the piezoelectric element extends, a force is generated to move toward the rod-shaped portion, thereby causing the rod-shaped portion to be subjected to a pushing force from the driving force generating portion. When the piezoelectric element contracts, a force is generated to move toward the weight portion, thereby causing the rod-shaped portion to be subjected to a force stretched by the driving force generating portion.

[0014] Furthermore, the third driving unit is provided along one side of the polygonal shape of the second moving frame, and the one side is not close to the first driving unit and is not close to the second driving unit.

[0015] Furthermore, the present invention provides a camera module using the camera actuator.

[0016] Furthermore, the present invention is an electronic device using the camera actuator.

[0017] The camera actuator of the present invention does not increase the size of its components and can efficiently arrange its components, thereby achieving a compact (thin) camera actuator as a whole. Furthermore, it is possible to provide a compact camera actuator having both an autofocus function and a camera shake correction function. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a front view schematically showing the structure of a camera actuator according to one embodiment of the present invention.

[0019] Figure 2 This figure shows the relationship between the first driving portion and a driving force transmission portion provided on the first moving frame of the camera actuator, as viewed from the end side of the rod-shaped portion of the first driving portion along the axial direction.

[0020] Figure 3 Schematically illustrates the structure and operation of the third driving unit in the camera actuator. DETAILED DESCRIPTION

[0021] A camera actuator 1 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the drawings are schematic diagrams, and the relationship between the illustrated contents of the drawings may be inaccurate or inconsistent.

[0022] The camera actuator 1 of this embodiment is used in a camera module mounted on an electronic device (information device) such as a smartphone. The camera actuator 1 has an automatic focus function and is used to correct the phenomenon of image blur caused by vibration transmitted to the information device when the user of the information device is holding the camera to shoot still images or videos by moving the camera optical axis according to the vibration, thereby obtaining a clear image. Figure 1As shown, the camera actuator 1 of this embodiment mainly includes a fixed frame 2, a first movable frame 3, a second movable frame 4, a lens unit 5, a first driving unit 6, a second driving unit 7 and a third driving unit 8. The frames 2 to 4 are arranged in the order of the fixed frame 2, the first movable frame 3, and the second movable frame 4 from the outside to the inside in a front view. In other words, the frames 2 to 4 are arranged in a "nested" structure on the same plane. The frames 2 to 4 are polygonal in a front view. Specifically, Figure 1 As shown, it is roughly square in front view. However, it is not limited to this. As long as the first movable frame 3 can move relative to the fixed frame 2 and the second movable frame 4 can move relative to the first movable frame 3, it can also be roughly rectangular or other shapes. In addition, the depth dimension of each frame 2 to 4 (in relation to the Figure 1 The dimensions in the direction perpendicular to the paper surface) can be dimensions that can support the balls 311, 411, 511 in a rotatable manner.

[0023] The fixing frame 2 constitutes the outer frame of the camera actuator 1 and is fixed to other parts of an information device such as a smart phone.

[0024] The first movable frame 3 is supported by the fixed frame 2 on the inner side and can move in the first direction relative to the fixed frame 2. As the first movable frame 3 moves in the first direction, the second movable frame 4 and the lens unit 5 provided on the inner side of the first movable frame 3 also move in the first direction. The first direction is in this embodiment. Figure 1 The X direction (left and right in the figure) is one of the movement directions of the lens unit 5 for correcting shake. In order to move the first movable frame 3 relative to the fixed frame 2, a first rolling element 31 capable of rolling is held between the first movable frame 3 and the fixed frame 2. In this embodiment, two balls 311 are provided as the first rolling element 31 on one side of the substantially square first movable frame 3 ( Figure 1 Each ball 311 is configured to roll while remaining within a predetermined range between the first movable frame 3 and the fixed frame 2. The other side of the first movable frame 3 ( Figure 1 The lower side) is provided with only the first drive unit 6 described later. However, this is not limited to this, and the first rolling element 31 can also be provided on the other side.

[0025] The second movable frame 4 is supported on the inner side by the first movable frame 3 and can move in a second direction orthogonal to the first direction relative to the first movable frame 3. As the second movable frame 4 moves in the second direction, the lens unit 5 provided on the inner side of the second movable frame 4 also moves in the second direction. The second direction is in this embodiment. Figure 1The Y direction (the vertical direction in the figure) is one of the movement directions of the lens unit 5 for correcting shake. In order to move the second movable frame 4 relative to the first movable frame 3, a second rolling element 41 capable of rolling is held between the second movable frame 4 and the first movable frame 3. In this embodiment, two balls 411 are provided as the second rolling element 41 on one side of the second movable frame 4 ( Figure 1 Each ball 411 rolls while remaining within a predetermined range between the second mobile rack 4 and the first mobile rack 3. The other side of the second mobile rack 4 ( Figure 1 The right side of the second moving frame 4 is provided with only the second driving part 7 described later. However, it is not limited thereto, and the other side can also be provided with a second rolling body 41. Figure 1 A third driving section 8 for moving a lens unit 5 described later is fixed to the inner side of the upper side.

[0026] The lens unit 5 is supported on the inner side by the second movable frame 4. The lens unit 5 has a substantially cylindrical inner space 5s, in which a camera lens is arranged. In addition, the optical structure of the lens unit 5 itself is well known. The lens unit 5 can move relative to the second movable frame 4 in a third direction that is orthogonal to the first direction and the second direction. The third direction is in this embodiment. Figure 1 The Z direction shown (with Figure 1 The direction perpendicular to the paper surface) is the moving direction of the lens unit 5 for the autofocus function. In addition, the optical axis direction of the lens unit 5 is in the same direction as the third direction. In order to move the lens unit 5 relative to the second movable frame 4, a third rolling body 51 capable of rolling is maintained between the lens unit 5 and the second movable frame 4. In this embodiment, as the third rolling body 51, two balls 511 are used as a set and are placed on one side of the roughly square second movable frame 4 ( Figure 1 The left side below) and the other side ( Figure 1 Each ball 511 is configured to roll while being held within a predetermined range between the second moving frame 4 and the lens unit 5.

[0027] The third rolling element 51 is located at a position closer to the end side than the center of one side of the substantially square second moving frame 4. Figure 1 The ball 511 on the left side is located at a position closer to the lower end than the upper and lower centers of the left side of the second movable frame 4. Figure 1The right ball 511 is positioned upward relative to the upper and lower center of the right side of the second movable frame 4. Furthermore, the balls 511 in the set of rolling elements 51 are positioned symmetrically about the second movable frame 4, 180° in a front view. This positioning of the third rolling elements 51 allows for a compact structure for moving the lens unit 5 in the third direction.

[0028] The first driving unit 6 is continuously provided on the fixed frame 2 and the first movable frame 3, and generates a driving force to move the first movable frame 3 in the first direction. The second driving unit 7 is continuously provided on the first movable frame 3 and the second movable frame 4, and generates a driving force to move the second movable frame 4 in the second direction.

[0029] The first drive unit 6 and the second drive unit 7 have the same structure. Therefore, the first drive unit 6 will be described as a representative. Figure 1 and Figure 2 As shown, the first driving portion 6 integrally comprises: a driving force generating portion 61; a rod-shaped portion 62 adjacent to one of the elongation direction and the shortening direction of the piezoelectric element of the driving force generating portion 61 and extending along the elongation direction and the shortening direction; and a weight portion 63 adjacent to the other of the elongation direction and the shortening direction of the driving force generating portion 61. Figure 1 In the example shown, a rod-shaped portion 62 is provided on one side (right side in the figure) in the longitudinal direction with the driving force generating portion 61 as a reference, and a weight portion 63 is provided on the other side (left side in the figure). As described later, the rod-shaped portion 62 is provided in order to transmit the force generated by the driving force generating portion 61 to the first movable frame 3. The weight portion 63 is a portion with a larger mass than the rod-shaped portion 62, and is provided in order to achieve a force balance with the rod-shaped portion 62. The rod-shaped portion 62 is made of, for example, alumina (density 3.9), and in this embodiment has a diameter of 0.7 mm and a length of 4 mm. The weight portion 63 is made of, for example, free-cutting brass (C3602), and in this embodiment has a diameter of 1.5 mm and a length of 1.25 mm. In addition, the material and size of the rod-shaped portion 62 and the weight portion 63 are not limited thereto.

[0030] The driving force generating unit 61 is composed of a piezoelectric element that is extended and shortened by electricity. By changing the direction of electricity supplied to the piezoelectric element, it can be extended or shortened. The piezoelectric element of this embodiment is extended by a positive external voltage and shortened by a negative external voltage. In the driving force generating unit 61, the piezoelectric element is the source of the driving force. Figure 1In the example shown, the piezoelectric element is extended and shortened in the left and right directions. When the piezoelectric element is extended, a force is generated that moves in the direction of the rod-shaped portion 62 (a force in the right direction as shown in the figure). The rod-shaped portion 62 is subjected to a pushing force from the driving force generating portion 61. On the other hand, when the piezoelectric element is shortened, a force is generated that moves in the direction of the weight portion 63 (a force in the left direction as shown in the figure). In addition, the rod-shaped portion 62 is also subjected to a force stretched by the driving force generating portion 61. Therefore, by controlling the direction of power supply to the piezoelectric element (specifically, the positive or negative of the applied voltage), the direction of the force (i.e., the force that moves the first movable frame 3 to one side or the other of the first direction (X direction)) exerted on the rod-shaped portion 62 can be changed.

[0031] like Figure 2 As shown, the outer peripheral surface of the rod-shaped portion 62 abuts against the driving force transmission portion 32 provided on the first movable frame 3. The driving force transmission portion 32 of this embodiment includes a support portion 321 having a V-shaped groove (the shape of the groove is not limited thereto) and a plate-shaped pressing portion 322 urged by a spring 323. In other words, as Figure 1 and Figure 2 As shown, the rod-shaped portion 62 pushes the driving force transmission portion 32 of the frame (the first driving portion 6 in this embodiment is the first movable frame 3) located on the opposite side of the side where the driving force generating portion 61 is fixed, through the force of a spring. The rod-shaped portion 62 and the driving force transmission portion 32 are not fixed, but are in contact with each other by applying a friction force. Therefore, the driving force transmission portion 32 may be offset along the length direction of the rod-shaped portion 62. Specifically, when the moving speed of the rod-shaped portion 62 is high (when it moves quickly), an offset will occur between it and the driving force transmission portion 32. The force generated by the elongation of the piezoelectric element is transmitted to the driving force transmission portion 32 via the rod-shaped portion 62. In detail, when the piezoelectric element is slowly (at a slow speed) extended by energizing the piezoelectric element, the rod-shaped portion 62 and the driving force transmission portion 32 are linked together without offset, and the force reaches the first movable frame 3 via the driving force transmission portion 32. As a result, the first movable frame 3 can be moved integrally relative to the first driving portion 6. Then, if the piezoelectric element is quickly shortened, the abrupt movement of the driving force transmission part 32 relative to the rod-shaped part 62 is retained due to the law of inertia. Therefore, the rod-shaped part 62 and the driving force transmission part 32 are offset and do not move in conjunction with each other. The force generated by the shortening of the piezoelectric element is not transmitted to the driving force transmission part 32 via the rod-shaped part 62 (strictly speaking, only a small amount is transmitted). By repeating the slow extension and rapid shortening of the piezoelectric element, the driving force transmission part 32 can be made to move in one direction (the direction of the elongation of the piezoelectric element) Figure 1 Furthermore, contrary to the above situation, by repeating the slow contraction and rapid extension of the piezoelectric element, the driving force transmission portion 32 can be moved in one direction ( Figure 1In this way, since the slow and rapid shape changes of the piezoelectric element are repeated multiple times, an intermittent force in one direction can be applied to the first movable frame 3. Therefore, according to this repetition, the first movable frame 3 can be moved a desired distance in the first direction (X direction).

[0032] The control unit that energizes the driving force generating unit 61 controls the energization so that the piezoelectric element undergoes both slow and rapid morphological changes. This control unit may be included in the camera actuator 1 itself, or may be included in the control unit on the main body of the information device. Specifically, the control unit applies voltage to the driving force generating unit 61 at different rates of change corresponding to the speed at which the piezoelectric element undergoes morphological changes. More specifically, the voltage applied to the piezoelectric element increases linearly (primary linearly) over time when the piezoelectric element is extended, and decreases linearly (primary linearly) over time when the piezoelectric element is contracted. The rate of change per predetermined time of the voltage decreasing when the piezoelectric element is rapidly contracted is greater than the rate of change per predetermined time of the voltage increasing when the piezoelectric element is slowly extended. In other words, the rising angle of the linear (primary linear) of the voltage increasing when the piezoelectric element is slowly extended is smaller, while the falling angle of the linear (primary linear) of the voltage decreasing when the piezoelectric element is rapidly contracted is larger. In one direction ( Figure 1 When the driving force transmitting portion 32 moves in the right direction (in the right direction), the voltage rises (from 0 to a positive predetermined value) - the voltage drops (from a positive predetermined value to a negative predetermined value) - the voltage rises (from a negative predetermined value to 0) as one cycle, and multiple cycles are continuously performed. Figure 1 When moving (leftward in the figure), conversely, a cycle consists of a voltage drop (from 0 to a negative predetermined value) - a voltage increase (from a negative predetermined value to a positive predetermined value) - a voltage drop (from a positive predetermined value to 0). The reciprocal of this cycle, i.e., the frequency, is set to 270 kHz in this embodiment, but the frequency is not limited to this and can be set arbitrarily.

[0033] The above describes the first driving unit 6, and the function of the second driving unit 7 is the same. By energizing the piezoelectric element of the driving force generating unit 71 of the second driving unit 7 in the same way as the first driving unit 6, the second movable frame 4 can be moved in the second direction (Y direction) relative to the second driving unit 7.

[0034] The position of the first movable frame 3 relative to the fixed frame 2 in the first direction (X direction) can be detected by, for example, a Hall effect element 91 provided on one side and a permanent magnet 92 provided on the other side. Furthermore, the position of the second movable frame 4 relative to the fixed frame 2 in the second direction (Y direction) can be detected by, for example, a Hall effect element 93 provided on one side and a permanent magnet 94 provided on the other side.

[0035] Furthermore, in this embodiment, the driving force generating unit 61 of the first driving unit 6 is fixed to the fixed frame 2. However, this is not limiting and the driving force generating unit 61 may also be fixed to the first movable frame 3. In this case, the first driving unit 6 moves as a whole. Similarly, in this embodiment, the driving force generating unit 71 of the second driving unit 7 is fixed to the first movable frame 3. However, this is not limiting and the driving force generating unit 71 may also be fixed to the second movable frame 4.

[0036] Next, the third drive unit 8 will be described. The third drive unit 8 is fixed to the second movable frame 4 and moves the lens unit 5 in the third direction (Z direction). The third drive unit 8 extends along one side of the polygonal shape (specifically, a substantially square shape) of the second movable frame 4. In addition, the third drive unit 8 is provided along one side of the polygonal shape of the second movable frame 4, which side is not close to the side of the first drive unit 6 ( Figure 1 ), and not the side close to the second drive unit 7 ( Figure 1 ), specifically, along the Figure 1 The third drive unit 8 can be provided in an unoccupied position where the first drive unit 6 and the second drive unit 7 are not present, thereby making the camera actuator 1 compact. The third drive unit 8 includes a drive source portion 81 composed of a first piezoelectric element 811 and a second piezoelectric element 812 that extend when energized, and are bonded together in a direction perpendicular to the direction of extension; and an abutment portion 82 that abuts the lens unit 5 and moves in accordance with the deformation of the drive source portion 81, describing elliptical trajectories V1 and V2.

[0037] The structure and operation of the third driving unit 8 are briefly shown in FIG. Figure 3 shown. Figure 3 The up and down directions in Figure 1 The third driving unit 8 includes a driving source 81 and a contact portion 82. The three protrusions provided on the upper edge of the third driving unit 8 are electrodes 83 for energizing the piezoelectric elements 811 and 812. The third driving unit 8 is on the side opposite to the contact portion 82 ( Figure 1 A support spring 84 is provided at a position (on the left side of the lens unit 5), and the support spring 84 applies force so as to push the abutting portion 82 to the pressed portion 52 of the lens unit 5.

[0038] The driving source portion 81 is composed of a first piezoelectric element 811 and a second piezoelectric element 812 that are extended by electricity and are bonded together in a direction perpendicular to the direction of extension. The first piezoelectric element 811 and the second piezoelectric element 812 are also arranged in a diagonal direction, and the driving source portion 81 is composed of two first piezoelectric elements 811 and two second piezoelectric elements 812. In this embodiment, since the driving source portion 81 is bent and deformed by applying electricity to the first piezoelectric element 811 and the second piezoelectric element 812, this is only applied to one side, not to both sides simultaneously. However, it is also possible to set the voltage so that electricity is applied to both sides simultaneously.

[0039] The contact portion 82 is located Figure 3 The right end portion shown in the figure and the protruding portion protruding in the longitudinal direction of the driving source portion 81. The abutment portion 82 is provided at the boundary position of the first piezoelectric element 811 and the second piezoelectric element 812 on the right side of the figure. The abutment portion 82 is a portion that outputs the deformation of the driving source portion 81 as a force. Therefore, the positional relationship of the abutment portion 82 relative to the driving source portion 81 is not limited to the present embodiment, and can also be provided on the side of the driving source portion 81, or offset relative to the first piezoelectric element 811 and the second piezoelectric element 812. The abutment portion 82 abuts against the outer peripheral surface of the ceramic pushed portion 52 which is a part of the lens unit 5, and depicts the deformation of the driving source portion 81 according to the deformation of the driving source portion 81. Figure 3 It moves along the elliptical trajectories V1 and V2 shown by the dotted lines.

[0040] In the Figure 3 When power is supplied to the first piezoelectric element 811 in the upper right and lower left regions with shadows, the regions extend in the horizontal direction. Figure 3 When power is supplied to the second piezoelectric element 812 located in the colorless lower right and upper left areas, the area maintains the shape of the rectangle shown in the figure. Therefore, the first piezoelectric element 811 is deformed in the direction described by the arrow in the figure, and the second piezoelectric element 812 is also deformed accordingly. Therefore, the right side portion shown in the figure of the aggregate of the piezoelectric elements in the driving source portion 81 (in this embodiment, an aggregate of two first piezoelectric elements 811 and two second piezoelectric elements 812) is bent and deformed into an inverted U shape, and the left side portion shown in the figure is bent and deformed into a U shape, so that the whole is deformed into a horizontal S shape. Therefore, the abutting portion 82 that abuts against the pushed portion 52 is bent and deformed to the reverse U shape. Figure 3 Since this movement is performed while the first piezoelectric element 811 is extending, it is achieved by Figure 3 The upper right half of the elliptical trajectory V1 shown by the dotted line in the lower right corner is moved. Figure 1 Thus, in this embodiment, the lens unit 5 can be directly driven by using the third driving section 8.

[0041] Next, when power is not supplied to the first piezoelectric element 811 located in the upper right and lower left areas with shadows, the areas shrink in the horizontal direction. The assembly of piezoelectric elements in the driving source section 81 returns from the inverted S-shape to the original rectangular shape shown in the figure. At this time, the contact portion 82 moves toward Figure 3 Since this movement is performed while the first piezoelectric element 811 is shrinking, it is achieved by Figure 3 The movement of the lower left half of the elliptical trajectory V1 shown by the dotted line. As described above, by turning on and off the power supply to the first piezoelectric element 811, the contact portion 82 depicts Figure 3 The elliptical trajectory shown in the lower right.

[0042] In contrast to the above, when power is supplied to the second piezoelectric element 812 located in the colorless lower right and upper left regions, the assembly of the piezoelectric elements in the driving source portion 81 is deformed into a "~" shape (or an inverted and horizontal S shape) opposite to the above, so that the contact portion 82 becomes the shape depicting the color. Figure 3 The lens unit 5 receives the force of this movement and moves to Figure 1 . In this way, the lens unit 5 can be moved in the third direction (Z direction in this embodiment) according to the power supply status of each piezoelectric element 811, 812 provided in the third drive unit 8. By constructing the third drive unit 8 in this way, in the camera actuator 1, the third drive unit 8 can be compactly arranged in the third direction (Z direction), and a driving force that moves the lens unit 5 in the third direction (Z direction) can be generated. In addition, the center portion 813 of the collection of four piezoelectric elements 811, 812 does not move even if power is supplied to each piezoelectric element 811, 812. Therefore, for example, when the drive source portion 81 is fixed to the outside, the center portion 813 serving as the fixed point can be fixed. The third drive unit 8 of this embodiment is fixed to the second movable frame 4 using a fixing component 85 mounted on the center portion 813.

[0043] As described above, the present embodiment is a camera actuator 1, which includes: a fixed frame 2; a first movable frame 3, which is supported by the fixed frame 2 on the inside and can move relative to the fixed frame 2 in a first direction; a second movable frame 4, which is supported by the first movable frame 3 on the inside and can move relative to the first movable frame 3 in a second direction perpendicular to the first direction; a lens unit 5, which is supported by the second movable frame 4 on the inside and can move relative to the second movable frame 4 in a third direction perpendicular to the first direction and the second direction; a first driving part 6, which is continuously provided on the fixed frame 2 and the first movable frame 3 and has a piezoelectric element that is extended by power supply, so that The first movable frame 3 moves in the first direction; the second driving unit 7 is continuously arranged on the first movable frame 3 and the second movable frame 4, and has a piezoelectric element that is extended by power supply, so that the second movable frame 4 moves in the second direction; and the third driving unit 8 is fixed on the second movable frame 4, so that the lens unit 5 moves in the third direction; the third driving unit 8 has: a driving source unit 81, which is composed of a first piezoelectric element 811 and a second piezoelectric element 812 that are extended by power supply and are bonded in a direction orthogonal to the extension direction; and an abutting unit 82, which abuts against the lens unit 5 and moves in a manner describing elliptical trajectories V1 and V2 according to the deformation of the driving source unit 81.

[0044] According to this configuration, since the first and second drive units 6 and 7 use piezoelectric elements that expand when energized as a source of driving force, it is possible to avoid increasing the number of components of the camera actuator 1. Furthermore, the drive source unit 81, which generates driving force from the piezoelectric elements 811 and 812, can directly drive the lens unit 5.

[0045] Furthermore, the second moving frame 4 is a polygonal frame, and the third driving unit 8 can extend along one side of the polygonal shape of the second moving frame 4 .

[0046] According to this configuration, since the third driving unit 8 extends along one side of the polygonal shape of the second moving frame 4 , the third driving unit 8 can be arranged compactly.

[0047] Furthermore, the third driving unit 8 may be provided along one side of the polygonal shape of the second moving frame 4 , the side not being close to the first driving unit 6 and the side not being close to the second driving unit 7 .

[0048] According to this structure, the third driving portion 8 can be provided at an empty position where the first driving portion 6 and the second driving portion 7 do not exist.

[0049] In addition, the second movable frame 4 is a rectangular or square frame, and the lens unit 5 can move in the third direction using a rolling body 51 arranged between it and the second movable frame 4. The rolling body 51 can be located at a position closer to the end side than the center of one side of the rectangular or square shape.

[0050] According to this configuration, the structure for moving the lens unit 5 in the third direction can be made compact.

[0051] In addition, the rolling bodies 51 are arranged in groups of two, and each rolling body 511 of a group can be arranged at a position symmetrically rotated by 180° in the second moving frame 4 .

[0052] According to this configuration, the structure for moving the lens unit 5 in the third direction can be made compact.

[0053] In addition, the first driving part 6 and the second driving part 7 can respectively include: a driving force generating part 61, which has a piezoelectric element that is extended and compressed by energizing; a rod-shaped part 62, which is adjacent to one side of the extension direction and the shortening direction of the piezoelectric unit and extends along the extension direction and the shortening direction; and a weight part 63, which is adjacent to the other side of the extension direction and the shortening direction of the driving force generating part.

[0054] In addition, the driving force generating portion 61 is composed of a piezoelectric element that extends and shortens when electricity is supplied. When the piezoelectric element extends, a force is generated to move toward the rod-shaped portion 62, thereby causing the rod-shaped portion 62 to be subjected to a pushing force from the driving force generating portion 61. When the piezoelectric element shortens, a force is generated to move toward the weight portion 63, thereby causing the rod-shaped portion 62 to be subjected to a force stretched by the driving force generating portion 61.

[0055] Furthermore, the third driving unit 8 is provided along one side of the polygonal shape of the second moving frame 4 , and the side is not close to the first driving unit 6 and is not close to the second driving unit 7 .

[0056] Furthermore, the present invention is a camera module using the camera actuator 1 .

[0057] Furthermore, the present invention is an electronic device using the camera actuator 1 .

[0058] As described above, the camera actuator 1 of this embodiment does not increase the size of its components and efficiently arranges its components, thereby achieving an overall small (thin) camera actuator 1. Furthermore, since the camera actuator 1 does not use magnetic force for driving, magnetic flux leakage does not occur.

[0059] Description of Reference Numerals

[0060] 1: Camera actuator

[0061] 2: Fixed bracket

[0062] 3: First mobile rack

[0063] 32: Driving force transmission unit

[0064] 4: Second mobile rack

[0065] 5: Lens unit

[0066] 51: rolling element, third rolling element

[0067] 511: Ball

[0068] 6: First drive unit

[0069] 61: Driving force generation unit

[0070] 62: Rod-shaped part

[0071] 63: Weight Department

[0072] 7: Second drive unit

[0073] 8: The third drive unit

[0074] 81: Driving source

[0075] 811: First piezoelectric element

[0076] 812: Second piezoelectric element

[0077] 82: Contact Department

[0078] V1, V2: elliptical trajectory

Claims

1. A camera actuator, characterized in that: have: Fixed frame; a first movable frame, which is supported on an inner side by the fixed frame and is movable in a first direction relative to the fixed frame; a second mobile frame supported on an inner side by the first mobile frame and movable relative to the first mobile frame in a second direction orthogonal to the first direction; a lens unit supported on an inner side by the second movable frame and movable relative to the second movable frame in a third direction orthogonal to the first direction and the second direction; a first driving portion, which is continuously provided on the fixed frame and the first movable frame and has a piezoelectric element that is extended by electricity, so as to move the first movable frame in the first direction; a second driving portion, which is continuously provided on the first movable frame and the second movable frame and has a piezoelectric element that is extended by electricity, so as to move the second movable frame in the second direction; as well as a third driving unit, fixed to the second movable frame, for moving the lens unit in the third direction; The third driving portion includes: a driving source portion, which is composed of a first piezoelectric element that expands when energized and a second piezoelectric element that are bonded together in a direction perpendicular to the expansion direction; and an abutting portion that abuts against the lens unit and moves in a manner describing an elliptical trajectory according to the deformation of the driving source portion. The third driving unit includes an aggregate of four piezoelectric elements including two of the first piezoelectric elements and two of the second piezoelectric elements. The center portion of the aggregate remains fixed even when power is supplied to each of the first piezoelectric elements or each of the second piezoelectric elements. In the driving source portion, two of the first piezoelectric elements are diagonally opposite to each other around the center portion, and two of the second piezoelectric elements are diagonally opposite to each other around the center portion. The third driving unit is fixed to the second movable frame by a fixing component installed at the center portion.

2. The camera actuator according to claim 1, wherein: The second mobile frame is a polygonal frame; The third driving portion extends along one side of the polygonal shape of the second moving frame.

3. The camera actuator according to claim 2, wherein: The third driving unit is provided along one side of the polygonal shape of the second moving frame, and the one side is not close to the first driving unit and is not close to the second driving unit.

4. The camera actuator according to any one of claims 1 to 3, characterized in that: The second movable frame is a rectangular or square frame; The lens unit is movable in the third direction by means of a rolling body provided between the lens unit and the second movable frame; The rolling element is located closer to an end portion than the center of one side of the rectangular or square shape.

5. The camera actuator according to claim 4, wherein: The rolling bodies are arranged in groups of two, and the rolling bodies in a group are respectively arranged at positions symmetrically rotated by 180 degrees in the second movable frame.

6. The camera actuator according to any one of claims 1 to 3, characterized in that: The first driving unit and the second driving unit respectively include: a driving force generating portion having a piezoelectric element that expands and contracts when energized; a rod-shaped portion adjacent to one of an elongation direction and a contraction direction of the piezoelectric element and extending along the elongation direction and the contraction direction; A weight portion is adjacent to the other of the expansion direction and the contraction direction of the piezoelectric element.

7. The camera actuator according to claim 6, wherein: The driving force generating unit is composed of a piezoelectric element that expands and contracts when energized. When the piezoelectric element expands, a force is generated to move the rod-shaped portion, and the rod-shaped portion is thereby pressed by the driving force generating portion. When the piezoelectric element contracts, a force is generated to move the weight portion, and accordingly, the rod-shaped portion is subjected to a force to be pulled by the driving force generating portion.

8. The camera actuator according to claim 6, wherein: The outer peripheral surface of the rod-shaped portion abuts against a driving force transmission portion provided on the first moving frame. The driving force transmission portion includes a support portion having a V-shaped groove and a plate-shaped pressing portion biased by a spring.

9. A camera module, characterized in that: The camera actuator according to any one of claims 1 to 8 is used.

10. An electronic device, characterized in that: The camera actuator according to any one of claims 1 to 8 is used.

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