Driving element

Abstract

To provide a drive element that can stably drive a movable part while achieving a smaller external size. [Solution] The drive element 1 comprises a movable part 2, a drive unit 3, and a plurality of connecting parts 4. The structure consisting of the movable part 2, the drive unit 3, and the plurality of connecting parts 4 has a shape that is substantially symmetrical with respect to the first axis A1 and the second axis A2 in a plan view. The drive unit 3 comprises a first support part 11, a second support part 12, a pair of first folded parts 21, a pair of second folded parts 22, a pair of first vibrating parts 31, a pair of second vibrating parts 32, and at least a pair of drive sources 33. The pair of first folded parts 21 and the pair of second folded parts 22 are connected to each other on the second axis A2.

Description

Technical Field

[0001] The present invention relates to a drive element that drives a movable part about a rotation axis.

Background Art

[0002] Drive elements for driving a movable part about a rotation axis are known. In this type of drive element, for example, a reflecting surface is arranged on the movable part, and the beam incident on the reflecting surface is scanned as the movable part rotates.

[0003] The following Patent Document 1 describes a drive element that rotates a mirror part (movable part) by a tuning fork oscillator. In this configuration, the mirror part is connected to the tuning fork oscillator by a beam-shaped support part extending along the rotation axis. Since the support part and the tuning fork oscillator are arranged only on one side of the mirror part, the drive element can be made compact. However, since only one side of the mirror part is supported and rotated, when the mirror part is repeatedly rotated, bending (dynamic bending) occurs in the mirror part. Such dynamic bending becomes more prominent as the frequency of repeated rotation increases.

[0004] Such dynamic bending can be suppressed by symmetrically arranging the structure composed of the support part and the tuning fork oscillator on both sides of the movable part. However, in this configuration, since the support part and the tuning fork oscillator are arranged on both sides of the movable part respectively, the drive element becomes larger.

[0005] The following Patent Document 2 describes a mirror device configured to support a movable part from both sides and apply a driving force to the movable part from only one side. This mirror device includes a rectangular frame-shaped fixing part that surrounds the movable part in a plan view. Two beam-shaped support parts extending along the rotation axis are connected to both sides of the movable part. One support part has one end connected to the movable part and the other end connected to a tuning fork type driving part. The driving part is connected to the fixing part. The other support part has one end connected to the movable part and the other end connected to the fixing part. In this configuration, since the driving part is arranged only on one side of the movable part, the device can be made more compact than when the driving parts are arranged on both sides of the movable part.

Prior Art Documents

[0006] [Patent Document 1] Patent No. 5045463 [Patent Document 2] U.S. Patent Publication No. 2023 / 0408808 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, in the configuration described in Patent Document 2, although the movable part can be supported from both sides, the fixed part is also positioned around the movable part on the opposite side from the drive unit, so the device cannot be sufficiently miniaturized.

[0008] In view of these challenges, the present invention aims to provide a drive element that can stably drive a movable part while miniaturizing its external dimensions. [Means for solving the problem]

[0009] A driving element according to the main aspect of the present invention comprises a movable part, a driving unit that rotates the movable part about a first axis, and a plurality of connecting parts that connect the driving unit to a support structure from both sides near a second axis that is perpendicular to the first axis in a plan view. The structure consisting of the movable part, the driving unit, and the plurality of connecting parts has a shape that is substantially symmetrical with respect to the first axis and the second axis in a plan view. The drive unit comprises a first support portion extending from the movable portion along the first axis, a second support portion extending from the movable portion in the direction opposite to the first support portion, a pair of first folding portions branching from the end of the first support portion and reaching the second axis, a pair of second folding portions branching from the end of the second support portion and reaching the second axis, a pair of first vibrating portions connected to the pair of first folding portions and extending at least in a direction away from the second axis, a pair of second vibrating portions connected to the pair of second folding portions and extending at least in a direction away from the second axis, and at least a pair of drive sources arranged in the pair of first vibrating portions and the pair of second vibrating portions, which vibrate these vibrating portions in directions perpendicular to the first axis and the second axis. The pair of first folding portions and the pair of second folding portions are connected to each other on the second axis.

[0010] According to the drive element of this embodiment, the vibration energy of a pair of first vibrating parts and a pair of second vibrating parts is applied to the movable part from both sides via the first folded part and the second folded part and the first support part and the second support part, causing the movable part to resonate around the first axis. Therefore, the movable part can be rotated repeatedly in a stable and efficient manner. Furthermore, the configuration for rotating the movable part, namely two sets having a first vibrating part and a second vibrating part on which the drive source is located, are arranged to sandwich the movable part in the direction of the second axis. Therefore, the shape of the drive element in the direction of the first axis can be significantly suppressed, and the shape of the drive element can be made more compact. Thus, according to the drive element of this embodiment, the movable part can be driven stably while achieving a smaller external size. [Effects of the Invention]

[0011] As described above, the present invention provides a drive element that can stably drive a movable part while miniaturizing its external dimensions.

[0012] The effects and significance of the present invention will become even clearer from the description of the embodiments shown below. However, the embodiments shown below are merely examples of how to implement the present invention, and the present invention is not limited in any way to those described in the embodiments below. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic top view showing the configuration of the drive element according to Embodiment 1. [Figure 2] Figure 2 is a top view showing the configuration of the drive element connected to the support structure according to Embodiment 1. [Figure 3] Figures 3(a) and 3(b) show the simulation results obtained by simulation of the displacement of each part during the resonant operation of the movable part according to Embodiment 1, respectively. [Figure 4] Figure 4 shows the simulation results obtained by simulation of the displacement of each part during the resonant operation of the movable part according to Embodiment 1. [Figure 5] Figures 5(a) to 5(d) show the simulation results obtained by simulation when the balance of natural frequencies between the first structure and the second structure according to Embodiment 1 is changed. [Figure 6] Figure 6 is a schematic top view showing the configuration of the drive element according to Embodiment 2. [Figure 7] Figures 7(a) to 7(d) show the simulation results obtained by simulation when the length of a pair of first vibrating parts is changed according to Embodiment 2. [Figure 8]Figs. 8(a) to 8(d) are diagrams showing simulation results obtained by simulation of the displacement amounts of respective parts of the drive element when the width of the mass adjustment part is changed according to Embodiment 2. [Figure 9] Fig. 9 is a top view schematically showing the configuration of the drive element according to Embodiment 3. [Figure 10] Fig. 10 is a diagram showing simulation results obtained by simulation of the displacement amounts of respective parts of the drive element when the movable part is resonated according to Embodiment 3. [Figure 11] Fig. 11 is a top view schematically showing an example of the overall configuration of the drive element according to Embodiment 3. [Figure 12] Fig. 12 is a bottom view schematically showing an example of the overall configuration of the drive element according to Embodiment 3. [Figure 13] Fig. 13 is a top view schematically showing the configuration of the drive element according to Embodiment 4. [Figure 14] Fig. 14 is a diagram showing simulation results obtained by simulation of the displacement amounts of respective parts of the drive element when the movable part is resonated according to Embodiment 4. [Figure 15] Fig. 15 is a top view schematically showing the configuration of the drive element according to Embodiment 5. [Figure 16] Figs. 16(a) and 16(b) are diagrams showing simulation results obtained by simulation of the displacement amounts of respective parts of the drive element when the movable part is resonated according to Embodiment 5. [Figure 17] Figs. 17(a) and 17(b) are diagrams showing simulation results obtained by simulation of the displacement amounts of respective parts of the drive element when the movable part is resonated according to Embodiment 5. [Figure 18] Fig. 18 is a top view schematically showing the configuration of the drive element according to Modification Example 1. [Figure 19] Figs. 19(a) and 19(b) are top views schematically showing the configurations of the drive elements according to Modification Examples 2 and 3, respectively. [Figure 20]Figures 20(a) and 20(b) are schematic top views showing the configuration of the drive element for modification examples 4 and 5, respectively. [Figure 21] Figures 21(a) and 21(b) are schematic top views showing the configuration of the drive element for modification examples 6 and 7, respectively. [Figure 22] Figures 22(a) and 22(b) are schematic top views showing the configuration of the drive element for modification examples 8 and 9, respectively. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the figures. For convenience, each figure is labeled with mutually orthogonal X, Y, and Z axes. The X and Y axes are parallel to the first and second axes, respectively, and the Z axis direction is the thickness direction of the drive element.

[0015] <Embodiment 1> Figure 1 is a schematic top view showing the configuration of the drive element 1. For convenience, the drive source 33 is hatched in Figure 1.

[0016] The drive element 1 comprises a movable part 2, a drive unit 3 that rotates the movable part 2 about the first axis A1, and a pair of connecting parts 4 that connect the drive unit 3 to the support structure 5 from both sides near the second axis A2. Here, the pair of connecting parts 4 extend along the second axis A2.

[0017] The structure, consisting of a movable part 2, a drive unit 3, and a pair of connecting parts 4, has a symmetrical shape with respect to a first axis A1 and a second axis A2 in a plan view. The first axis A1 and the second axis A2 are parallel to the Y axis and the X axis, respectively. The first axis A1 is the pivot axis of the movable part 2. The center of the movable part 2 coincides with the intersection of the first axis A1 and the second axis A2. The drive element 1 causes the movable part 2 to repeatedly rotate around the first axis A1 at the target resonant frequency.

[0018] The movable part 2 consists of a driven part 2a that is circular in plan view, and a frame part 2b that surrounds the driven part 2a and is connected to the driven part 2a near the position of the driven part 2a furthest from the first axis A1. The driven part 2a does not necessarily have to be circular and may have other shapes such as an ellipse or a square.

[0019] A reflective surface 2c is positioned on the upper surface of the driven part 2a. For example, the reflective surface 2c is formed by creating a highly reflective metal film or dielectric multilayer film on the upper surface of the driven part 2a. However, this is not the only option; if the upper surface of the driven part 2a itself has high reflectivity, this upper surface may be used as the reflective surface 2c. Alternatively, the upper surface of the driven part 2a may be mirror-finished to form the reflective surface 2c.

[0020] The drive unit 3 comprises a first support portion 11, a second support portion 12, a pair of first folded portions 21, a pair of second folded portions 22, a pair of first vibrating portions 31, a pair of second vibrating portions 32, and a pair of drive sources 33.

[0021] The first support portion 11 extends from the movable portion 2 along the first axis A1, and the second support portion 12 extends from the movable portion 2 in the opposite direction to the first support portion 11. The first support portion 11 and the second support portion 12 are connected to the frame portion 2b of the movable portion 2. A pair of first folded portions 21 branch off from the ends of the first support portion 11 and reach the second axis A2. A pair of second folded portions 22 branch off from the ends of the second support portion 12 and reach the second axis A2. The pair of first folded portions 21 and the pair of second folded portions 22 are connected to each other on the second axis A2. The movable portion 2 and the first support portion 11 are surrounded by the pair of first folded portions 21 and the pair of second folded portions 22.

[0022] The pair of first vibrating sections 31 are connected to the pair of first folded sections 21 via the pair of connecting sections 41 and extend in a direction away from the second axis A2 (positive Y-axis direction). Here, the pair of first vibrating sections 31 extend parallel to the first axis A1. In plan view, each of the pair of first vibrating sections 31 is rectangular in shape, with the ends on the side of the pair of connecting sections 41 gradually widening. The ends of the pair of first vibrating sections 31 opposite to the pair of connecting sections 41 are open. The pair of connecting sections 41 connect the pair of first vibrating sections 31 to the pair of first folded sections 21 at the position of the second axis A2.

[0023] The pair of second vibrating sections 32 are connected to the pair of second folded sections 22 via the pair of connecting sections 41, and extend in a direction away from the second axis A2 (negative Y-axis direction). Here, the pair of second vibrating sections 32 extend parallel to the first axis A1. In plan view, the shape of the pair of second folded sections 22 is symmetrical with respect to the first vibrating section 31 with respect to the second axis A2. The pair of connecting sections 41 connect the pair of second vibrating sections 32 to the pair of second folded sections 22 at the position of the second axis A2.

[0024] A pair of first vibrating parts 31 and a pair of second vibrating parts 32 are connected to each other on the second axis A2. A common drive source 33 is provided for the connected first vibrating parts 31 and second vibrating parts 32. That is, one drive source 33 is provided across the first vibrating parts 31 and second vibrating parts 32 on the positive X-axis side, and another drive source 33 is provided across the first vibrating parts 31 and second vibrating parts 32 on the negative X-axis side.

[0025] Each drive source 33 vibrates its corresponding first vibrating section 31 and second vibrating section 32 in a direction perpendicular to the first axis A1 and second axis A2 (Z-axis direction). In this embodiment, the drive source 33 is composed of a piezoelectric material in which a piezoelectric thin film is sandwiched between an upper electrode and a lower electrode. The drive source 33 expands and contracts in the Y-axis direction when a drive signal that changes between positive and negative is applied. As a result, the first vibrating section 31 and second vibrating section 32 corresponding to each drive source 33 vibrate in the Z-axis direction.

[0026] Each of the pair of first folded portions 21 and the pair of second folded portions 22 has a shape that includes an inflection point P0. For convenience, in Figure 1, the inflection point P0 is shown only for the first folded portion 21 and the pair of second folded portions 22 on the negative X-axis side, but the first folded portion 21 and the second folded portion 22 on the negative X-axis side also have an inflection point P0 at a position symmetric to these inflection points P0 with respect to the first axis A1.

[0027] Each first folded section 21 comprises a curved section 21a, a first straight section 21b, a second straight section 21c, and a relay section 21d.

[0028] The curved section 21a is the part that branches off from the first support section 11 and curves convexly in the positive Y-axis direction. The first straight section 21b extends parallel to the first axis A1 at a predetermined distance from the first support section 11 and connects to the curved section 21a. The second straight section 21c extends parallel to the first axis A1 at a position further from the first support section 11 than the first straight section 21b and connects to the second axis A2. The intermediate section 21d connects the first straight section 21b and the second straight section 21c. The intermediate section 21d has a downward-convex portion and an upward-convex portion in the Y-axis direction. An inflection point P0 exists at the position where these portions connect.

[0029] The pair of second folded sections 22 have a shape symmetrical to the pair of first folded sections 21 with respect to the second axis A2. Therefore, each second folded section 22, like the first folded section 21, has a curved section 22a, a first straight section 22b, a second straight section 22c, and a connecting section 22d. Similar to the connecting section 21d, the connecting section 22d has an upwardly convex portion and a downwardly convex portion in the Y-axis direction. An inflection point P0 exists at the position where these sections connect.

[0030] As described above, the pair of first vibrating sections 31 and the pair of second vibrating sections 32 are connected to the pair of first folded sections 21 and the pair of second folded sections 22 near the second axis A2. Therefore, the pair of first vibrating sections 31 and the pair of second vibrating sections 32 are connected to the pair of first folded sections 21 and the pair of second folded sections 22 at positions closer to the second axis A2 than their respective inflection points P0.

[0031] Figure 2 is a top view showing the configuration of the drive element 1 when connected to the support structure 5.

[0032] In the example shown in Figure 2, the support structure 5 is a frame structure that encloses the negative Y-axis area of ​​the drive unit 3 in a rectangular shape. Here, the support structure 5 orbits the outside of the negative Y-axis area of ​​the drive unit 3 parallel to the XY plane. However, the support structure 5 is not limited to this configuration; it may also be configured to wrap around and connect in the negative Z-axis direction from the connection point with the pair of connecting parts 4.

[0033] The base material of the drive element 1 has the same contour as the drive element 1 in a plan view and has a constant thickness. The thickness of the base material is smaller than the width of each part of the drive element 1. The drive source 33 and the reflective surface 2c are arranged in corresponding areas on the upper surface of the base material. Wiring (not shown) for supplying drive signals to each drive source 33 is arranged on the upper surface (positive Z-axis side) of the connection part 4. Furthermore, terminals (not shown) connected to these wires are arranged on the upper surface of the support structure 5. The wires and terminals may have a layered structure similar to the piezoelectric material constituting the drive source 33. The lower electrode of the wire may be extended to the area of ​​the ground terminal to become a ground terminal.

[0034] Furthermore, within the region of the support structure 5, a layer made of a predetermined material is laminated on the lower surface of the base material. This increases the thickness of the support structure 5 and enhances its rigidity. The thickness of the laminated layer is constant. The material of the laminated layer may be different from that of the base material, or it may be the same material as the base material.

[0035] The base material is integrally formed from, for example, silicon. However, the material constituting the base material is not limited to silicon; other materials may also be used. Preferably, the material constituting the base material is a material with high mechanical strength and Young's modulus, such as metal, crystal, glass, or resin. In addition to silicon, titanium, stainless steel, elimperium, brass alloy, etc., can be used as such materials. The material of the layer laminated on the support structure 5 can be similarly selected.

[0036] In this embodiment, the drive element 1 applies a drive signal that changes between positive and negative at a predetermined frequency to a pair of drive sources 33, causing the pair of first vibrating parts 31 and 2 vibrating parts 32 on the positive X-axis side and the pair of first vibrating parts 31 and 2 vibrating parts 32 on the negative X-axis side to vibrate up and down in opposite phases to each other, thereby causing the movable part 2 to repeatedly rotate around the first axis A1. That is, the vertical vibration of each pair propagates to the first support part 11 and the second support part 12 via the pair of first folding parts 21 and the pair of second folding parts 22, causing the first support part 11 and the second support part 12 to twist in the same direction around the first axis A1. As a result, the movable part 2 repeatedly rotates around the first axis A1.

[0037] The length, thickness, and stiffness of each part of the drive element 1 are adjusted so that the movable part 2 (driven part 2a) rotates repeatedly at a target frequency. In other words, the length, thickness, and stiffness of each part of the drive element 1 are adjusted so that the resonant frequency of the movable part 2 is near the target frequency. A drive signal is applied to a pair of drive sources 33 (piezoelectric bodies) so that the movable part 2 (driven part 2a) rotates repeatedly at a predetermined deflection angle (for example, ±10° or more) with respect to the neutral position.

[0038] As described above, a reflective surface 2c is positioned on the movable part 2 (driven part 2a). The reflective surface 2c reflects light incident from above the movable part 2 in a direction corresponding to the swing angle of the movable part 2. As a result, the light incident on the reflective surface 2c (for example, laser light) is deflected and scanned as the movable part 2 rotates. By positioning the reflective surface 2c on the movable part 2 (driven part 2a), the driving element 1 is configured as an optical deflection element.

[0039] Figures 3(a), 3(b), and 3(b) and 4 respectively show the simulation results obtained by simulating the displacement of each part during the resonant operation of the movable part 2.

[0040] Figures 3(a), (b), and 4 actually use colors corresponding to the magnitude of displacement, but for convenience, these colors are shown here in grayscale. The actual color scales (horizontal rectangular color scales) in each figure have red at the left end, blue at the right end, and green in the middle, with the color gradually transitioning horizontally. For convenience, the color scale in Figure 3(a) differs from the color scales in Figures 3(b) and 4 in how the displacement amounts for each color are set.

[0041] Figures 3(a) and 3(b) show the simulation results obtained by simulation when the movable part 2 resonates in in-phase mode. Figure 4 shows the simulation results obtained by simulation when the movable part 2 resonates in out-of-phase mode.

[0042] Here, the in-phase mode is an operating mode in which the movable part 2 repeatedly rotates in phase with respect to the pair of first vibrating parts 31 and the pair of second vibrating parts 32. The out-of-phase mode is an operating mode in which the movable part 2 repeatedly rotates in opposite phase with respect to the pair of first vibrating parts 31 and the pair of second vibrating parts 32.

[0043] For example, referring to Figures 3(a) and (b), the displacement direction of the first vibrating section 31 and the second vibrating section 32 on the positive X-axis side (indicated by solid arrows in the negative Z-axis direction) is the same as the rotation direction of the portion of the movable section 2 on the positive X-axis side (indicated by dashed arrows in the negative Z-axis direction). Also, the displacement direction of the first vibrating section 31 and the second vibrating section 32 on the negative X-axis side (indicated by solid arrows in the positive Z-axis direction) is the same as the rotation direction of the portion of the movable section 2 on the negative X-axis side (indicated by dashed arrows in the positive Z-axis direction). Therefore, in this resonant operation, the pair of first vibrating sections 31 and the pair of second vibrating sections 32 and the movable section 2 deform and rotate in phase. This type of operation mode is called an in-phase mode.

[0044] In contrast, referring to Figure 4, the displacement direction of the first vibrating section 31 and the second vibrating section 32 on the positive X-axis side (positive Z-axis direction indicated by solid arrows) is opposite to the rotation direction of the portion of the movable section 2 on the positive X-axis side (negative Z-axis direction indicated by dashed arrows). Also, the displacement direction of the first vibrating section 31 and the second vibrating section 32 on the negative X-axis side (negative Z-axis direction indicated by solid arrows) is opposite to the rotation direction of the portion of the movable section 2 on the negative X-axis side (positive Z-axis direction indicated by dashed arrows). Therefore, in this resonant operation, the pair of first vibrating sections 31 and the pair of second vibrating sections 32 and the movable section 2 deform and rotate in opposite phases. This mode of operation is called the out-of-phase mode.

[0045] In the simulation shown in Figure 3(a), it is assumed that the rigidity of the pair of connecting parts 4 is high and that deformation is unlikely to occur in the pair of connecting parts 4. In this case, by vibrating the first vibrating part 31 and the second vibrating part 32 on the positive X-axis side and the first vibrating part 31 and the second vibrating part 32 on the negative X-axis side in opposite phases, the movable part 2 can be repeatedly rotated around the first axis A1 at the resonance frequency due to the in-phase mode.

[0046] In contrast, the simulation in Figure 3(b) assumes that the rigidity of the pair of connecting parts 4 is low and that deformation is likely to occur in the pair of connecting parts 4. In this case, when the first vibrating part 31 and the second vibrating part 32 on the positive X-axis side and the first vibrating part 31 and the second vibrating part 32 on the negative X-axis side are vibrated in opposite phases, the pair of connecting parts 4 deform as shown in Figure 3(b), and the frequency of the repetitive rotation in the movable part 2 decreases significantly compared to the case in Figure 3(a). For this reason, when the rigidity of the pair of connecting parts 4 is low and deformation is likely to occur in the pair of connecting parts 4, it is difficult to operate the movable part 2 normally depending on the in-phase mode.

[0047] Therefore, when configuring the drive element 1 to resonate the movable part 2 in a common-mode at the target frequency, it is necessary to increase the rigidity of the pair of connecting parts 4 to suppress deformation of the pair of connecting parts 4. For example, deformation of the pair of connecting parts 4 can be suppressed by reducing the length of the pair of connecting parts 4 and, similar to the support structure 5, by laminating other layers on the lower surface of the base material of the connecting parts 4.

[0048] Next, in the simulation shown in Figure 4, similar to the case in Figure 3(b), it is assumed that the rigidity of the pair of connecting parts 4 is low and that deformation is likely to occur in the pair of connecting parts 4. However, when the movable part 2 resonates in reverse-phase mode, the drive element 1 can be configured such that almost no deformation occurs in the pair of connecting parts 4, as shown in Figure 4. Therefore, the movable part 2 can be stably and repeatedly rotated at the target resonant frequency.

[0049] Thus, in the reverse-phase mode, no deformation occurs in the pair of connecting parts 4 during the resonant operation of the movable part 2 because the first structure, consisting of a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32, and the second structure, consisting of the components of the drive unit 3 other than the first structure and the movable part 2, vibrate (rotate) in opposite phases. In other words, the vibrations that occur in the first structure and the second structure during the resonant operation of the movable part 2 can cancel each other out near the pair of connecting parts 41 that connect the first structure and the second structure. As a result, the area near the connecting parts 41 can be set to a nearly stationary state, and the leakage of vibration from the drive unit 3 to the pair of connecting parts 4 and the support structure 5 beyond them can be suppressed.

[0050] Therefore, in order to stably resonate the movable part 2 at the target frequency while suppressing vibration leakage to the support structure 5, it is preferable to configure the drive element 1 so that the movable part 2 resonates in an inverse phase mode at the target frequency. In this case, the drive element 1 is configured such that the resonant operation of the movable part 2 at the target frequency is realized in a so-called inverse phase mode, by adjusting the parameters that contribute to the resonant operation, such as the thickness, length, and stiffness of each part.

[0051] Furthermore, in order to effectively suppress vibrations at the pair of connection points 4 and reliably suppress vibration leakage to the support structure 5, the natural frequencies of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32) and the natural frequencies of the second structure (components of the drive unit 3 other than the first structure and the movable parts 2) should be adjusted so that the position of the vibration node generated by the reverse-phase mode (resonant operation in opposite phase) is near the connection point between the pair of connection points 4 and the drive unit 3. Here, a node is a position or range where the direction of vibration switches and no vibration occurs.

[0052] In the example shown in Figure 4, the natural frequencies of the first and second structures are adjusted so that a node occurs near the position on the second axis A2 where the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are connected (near the connection point between the pair of connecting parts 4 and the drive unit 3). If the balance of the natural frequencies of the first and second structures deviates from the state shown in Figure 4, the position of the node shifts.

[0053] For example, if the natural frequency of the first structure decreases from the balanced state shown in Figure 4, the nodes move toward the tips of the first vibrating section 31 and the second vibrating section 32. Conversely, if the natural frequency of the first structure increases from the balanced state shown in Figure 4, the nodes move toward the first folded section 21 and the second folded section 22. In other words, the position of the nodes shifts toward the structure whose natural frequency has decreased relative to the balanced state shown in Figure 4.

[0054] Here, the natural frequency can be changed by adjusting the mass and stiffness of each structure. That is, the natural frequency decreases as the mass of the object increases, and increases as the stiffness (rigidity) increases. For example, if the length of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 is reduced, and the mass of the first structure is reduced, the natural frequency of the first structure increases. In this way, by adjusting the balance of natural frequencies between the first and second structures, the position of the nodes can be set near the connection point between the pair of connecting parts 4 and the drive unit 3.

[0055] Figures 5(a) to 5(d) show the simulation results obtained by simulating the displacement of each part of the drive element 1 when the balance of natural frequencies between the first structure and the second structure is changed.

[0056] Figures 5(a) to 5(d) show the simulation results for the positive Y-axis range of the drive element 1. For convenience, the color simulation results in Figures 5(a) to 5(d) are shown in grayscale. In this simulation, the natural frequency of the first structure is adjusted by changing the length of the pair of first vibrating parts 31.

[0057] Figure 5(b) shows the simulation results when the natural frequencies of the first and second structures are adjusted so that nodes S1 occur near the connection point between the pair of connecting parts 4 and the drive unit 3, similar to Figure 4.

[0058] Figure 5(a) shows the simulation results when the length of the pair of first vibrating sections 31 is reduced compared to the case in Figure 5(b), thereby increasing the natural frequency of the first structure. In this case, the node S1 has moved from the position shown in Figure 5(b) to near the base of the first folded section 21.

[0059] Figure 5(c) shows the simulation results when the length of the pair of first vibrating sections 31 is increased compared to the case in Figure 5(b), thereby lowering the natural frequency of the first structure. In this case, node S1 moves from the position shown in Figure 5(b) toward the tip of the first vibrating section 31.

[0060] Figure 5(d) shows the simulation results when the length of the pair of first vibrating sections 31 is further increased compared to the case in Figure 5(c), thereby further reducing the natural frequency of the first structure. In this case, node S1 has moved further toward the tip of the first vibrating section 31 than in the position shown in Figure 5(c).

[0061] Figures 5(a), (c), and (d) show the nodes S1 that occur in the positive Y-axis range of the drive element 1. However, nodes also occur in the negative Y-axis range of the drive element 1, at positions symmetrical to the nodes S1 shown in these figures with respect to the second axis A2.

[0062] In this way, by adjusting the balance between the natural frequencies of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32) and the natural frequencies of the second structure (components of the drive unit 3 other than the first structure and the movable part 2), the position of the node S1 that occurs during the resonant operation of the movable part 2 can be adjusted. Therefore, by adjusting the length, thickness, and stiffness of each part so that the position of the node S1 is near the connection position between the pair of connecting parts 4 and the drive unit 3, and balancing the natural frequencies of the first structure and the second structure, vibrations that occur in the pair of connecting parts 4 during the resonant operation of the movable part 2 can be effectively suppressed, and vibration leakage to the support structure 5 can be reliably suppressed.

[0063] <Effects of Embodiment 1> According to Embodiment 1, the following effects are achieved.

[0064] As shown in Figure 1, the drive element 1 comprises a movable part 2, a drive unit 3 that rotates the movable part 2 about the first axis A1, and a plurality of connecting parts 4 that connect the drive unit 3 to the support structure 5 from both sides near the second axis A2 which is perpendicular to the first axis A1 in a plan view. The structure consisting of the movable part 2, the drive unit 3, and the plurality of connecting parts 4 has a shape that is symmetrical with respect to the first axis A1 and the second axis A2 in a plan view. The drive unit 3 includes a first support portion 11 extending from the movable portion 2 along the first axis A1, a second support portion 12 extending from the movable portion 2 in the opposite direction to the first support portion 11, a pair of first return portions 21 branching from the end of the first support portion 11 and reaching the second axis A2, a pair of second return portions 22 branching from the end of the second support portion 12 and reaching the second axis A2, a pair of first vibrating portions 31 connected to the pair of first return portions 21 and extending at least in a direction away from the second axis A2, a pair of second vibrating portions 32 connected to the pair of second return portions 22 and extending at least in a direction away from the second axis A2, and at least a pair of drive sources 33 arranged on the pair of first vibrating portions 31 and the pair of second vibrating portions 32, which vibrate these vibrating portions in a direction perpendicular to the first axis A1 and the second axis A2 (Z-axis direction). The pair of first folded portions 21 and the pair of second folded portions 22 are connected to each other on the second axis A2.

[0065] With this configuration, as shown in Figures 3(a), (b) and 4, the movable part 2 can be repeatedly rotated around the first axis A1 by vibrating one pair of first vibrating parts 31 and second vibrating parts 32 aligned in the Y-axis direction and the other pair of first vibrating parts 31 and second vibrating parts 32 aligned in the Y-axis direction in opposite phases. That is, the vibration energy of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 is applied to the movable part 2 from both sides in the Y-axis direction via the first folded part 21 and the second folded part 22 and the first support part 11 and the second support part 12, causing the movable part 2 to resonate around the first axis A1. Therefore, the movable part 2 can be repeatedly rotated stably and efficiently. Furthermore, the configuration for rotating the movable part 2, namely two pairs each having a first vibrating part 31 and a second vibrating part 32 on which a drive source 33 is located, is arranged to sandwich the movable part 2 in the direction of the second axis A2. Therefore, the shape of the drive element 1 in the direction of the first axis A1 (Y-axis direction) can be significantly suppressed, and the shape of the drive element 1 can be made more compact. Accordingly, the drive element 1 according to this embodiment can stably drive the movable part 2 while reducing the external size.

[0066] As shown in Figure 1, one and the other of the pair of first vibrating parts 31 and one and the other of the pair of second vibrating parts 32 are connected to each other on the second axis A2, and a common drive source 33 is provided for the connected first vibrating parts 31 and second vibrating parts 32.

[0067] This configuration allows for greater length of the first vibrating section 31 and the second vibrating section 32, as well as the length of the drive source 33, enabling efficient driving of the movable section 2. Furthermore, since a common drive source 33 is provided for the interconnected first vibrating section 31 and the second vibrating section 32, the configuration of the drive source 33 can be simplified, and the number of wires connected to the drive source 33 can be reduced.

[0068] As shown in Figure 4, it is preferable that the drive unit 3 is configured such that, at the target frequency, the movable part 2 resonates around the first axis A1 in opposite phase (inverse phase mode) relative to the pair of first vibrating parts 31 and the pair of second vibrating parts 32.

[0069] With this configuration, at the target frequency, the movable part 2 resonates in opposite phase to the pair of first vibrating parts 31 and the pair of second vibrating parts 32, so that the vibrations generated in the drive unit 3 during the resonant operation cancel each other out. Therefore, unwanted vibrations generated during the resonant operation of the movable part 2 can be effectively suppressed.

[0070] As shown in Figure 1, the pair of first folded portions 21 and the pair of second folded portions 22 each have a shape that includes an inflection point P0, and the pair of first vibrating portions 31 and the pair of second vibrating portions 32 are connected to the pair of first folded portions 21 and the pair of second folded portions 22 at positions on the second axis A2 side of the respective inflection point P0.

[0071] This configuration prevents the torsion generated in the first support portion 11 and the second support portion 12 during the resonant operation of the movable portion 2 from propagating to the connecting portion 4. Specifically, in the range from the inflection point P0 towards the movable portion 2 of the pair of first folded portions 21 and the pair of second folded portions 22, torsion occurs in accordance with the torsion of the first support portion 11 and the second support portion 12, but in the range from the inflection point P0 towards the second axis A2, vibration occurs mainly in a direction perpendicular to the first axis A1 and the second axis A2 (Z-axis direction) due to vibrations from the first vibrating portion 31 and the second vibrating portion 32. In other words, the torsion generated in the first support portion 11 and the second support portion 12 is prevented from propagating to the range of the first folded portion 21 and the second folded portion 22 on the second axis A2 side of their respective inflection points P0. Therefore, the generation of torsion in each connecting portion 4 during the resonant operation of the movable portion 2 can be suppressed.

[0072] As shown in Figure 5(b), it is preferable that the natural frequencies of the first structure, consisting of a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32, and the natural frequencies of the second structure, consisting of components of the drive unit 3 other than the first structure and the movable parts 2, are adjusted so that the position of the node S1 where the direction of vibration caused by the resonant operation in opposite phase (inverse phase mode) switches is near the connection position between the multiple connection parts 4 and the drive unit 3.

[0073] This configuration suppresses the propagation of vibrations generated during the resonant operation of the movable part 2 to the connecting part 4, thereby maintaining the connecting part 4 in a nearly vibration-free state. As a result, it is possible to suppress vibration leakage from the connecting part 4 to the support structure 5, and the movable part 2 can be operated stably even if the rigidity of the connecting part 4 and the support structure 5 beyond it is low, as shown in Figure 3(b).

[0074] As shown in Figure 1, the movable part 2 consists of a driven part 2a and a frame part 2b that, in a plan view, surrounds the driven part 2a and is connected to the driven part 2a near the position of the driven part 2a furthest from the first axis A1. The first support part 11 and the second support part 12 are connected to the frame part 2b.

[0075] In this configuration, the area of ​​the driven part 2a furthest from the first axis A1, which is the pivot axis, that is, the area of ​​the driven part 2a where distortion is most likely to occur during rotation, is supported by the frame part 2b, and driving force from the first support part 11 and the second support part 12 is applied to this end. Therefore, distortion of the driven part 2a can be effectively suppressed when the movable part 2 rotates.

[0076] As shown in Figure 1, the movable part 2 has a reflective surface 2c.

[0077] With this configuration, the driving element 1 can be used as an optical deflector.

[0078] <Embodiment 2> Figure 6 is a schematic top view showing the configuration of the drive element 1 according to Embodiment 2.

[0079] As shown in Figure 6, the drive element 1 according to Embodiment 2 differs from the drive element 1 in Figure 1 according to Embodiment 1 in the configuration of the pair of first vibrating parts 31 and the pair of second vibrating parts 32. Specifically, the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are each provided with a mass adjustment part 31a and a mass adjustment part 32a for adjusting their own mass. In this case, the width of the ends of the pair of first vibrating parts 31 is widened inward to form the pair of mass adjustment parts 31a, and the width of the ends of the pair of second vibrating parts 32 is widened inward to form the pair of mass adjustment parts 32a.

[0080] The configuration of the drive element 1 other than the mass adjustment sections 31a and 32a is the same as in Embodiment 1 described above. In Embodiment 2 as well, the structure consisting of the movable section 2, the drive unit 3, and the pair of connecting sections 4 has a shape that is symmetrical with respect to the first axis A1 and the second axis A2 in a plan view.

[0081] Similar to the simulations in Figures 5(a) to (d), in the configuration of Figure 6, the position of node S1 can be adjusted by adjusting the length L11 of the pair of first vibrating parts 31 and the pair of second vibrating parts 32. Furthermore, in the configuration of Figure 6, the natural frequency of the first structure (pair of drive sources 33, pair of first vibrating parts 31 and pair of second vibrating parts 32) can be changed by adjusting the width W11 of the respective mass adjustment parts 31a and 32a, thereby adjusting the mass of the pair of first vibrating parts 31 and the pair of second vibrating parts 32, and thus the position of node S1 can be adjusted.

[0082] Figures 7(a) to 7(d) show the simulation results obtained by simulating the displacement of each part of the drive element 1 when the length L11 in Figure 6 is changed.

[0083] Figures 7(a), (c), and (d) show the simulation results for the positive Y-axis range of the drive element 1, while Figure 7(b) shows the simulation results for the entire range of the drive element 1. The simulation conditions (length L11 in Figure 6) in Figures 7(a) and (b) are the same. For convenience, the color simulation results in Figures 7(a) to (d) are shown in grayscale.

[0084] In Figure 7(a), the length L11 of the pair of first vibrating sections 31 is adjusted so that a node S1 is generated near the connecting section 41. In Figure 7(c), the length L11 is set to be larger than in Figure 7(a). In Figure 7(d), the length L11 is set to be smaller than in Figure 7(a). In all of Figures 7(a) to (d), the width W11 in Figure 6 is the same.

[0085] In Figure 7(c), the length L11 is larger than in Figure 7(a), which increases the mass of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32), and the natural frequency of the first structure becomes lower than in Figure 7(a). As a result, in Figure 7(c), the position of the node S1 is shifted towards the pair of first vibrating parts 31 compared to the case in Figure 7(a). In this case, the entire drive element 1 has nodes S1 near the base of the pair of first vibrating parts 31 as well as near the base of the pair of second vibrating parts 32.

[0086] In Figure 7(d), the length L11 is smaller than in Figure 7(a), so the mass of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32) decreases, and the natural frequency of the first structure becomes higher than in Figure 7(a). As a result, in Figure 7(d), the position of the node S1 is shifted towards the pair of first folded parts 21 compared to the case of Figure 7(a). In this case, in the entire drive element 1, nodes S1 are generated not only in the second straight part 21c of the pair of first folded parts 21 (see Figure 6), but also in the second straight part 22c of the pair of second folded parts 22 (see Figure 6).

[0087] Thus, in the configuration shown in Figure 6, the position of node S1 can be adjusted by adjusting the length L11.

[0088] Figures 8(a) to 8(d) show the simulation results obtained by simulating the displacement of each part of the drive element 1 when the width W11 in Figure 6 is changed.

[0089] Figures 8(a), (c), and (d) show the simulation results for the positive Y-axis range of the drive element 1, while Figure 8(b) shows the simulation results for the entire range of the drive element 1. The simulation conditions (width W11 in Figure 6) in Figures 8(a) and (b) are the same. For convenience, the color simulation results in Figures 8(a) to (d) are shown in grayscale.

[0090] In Figure 8(a), the width W11 of the mass adjustment section 31a is adjusted so that a node S1 is generated near the connection point between the pair of first vibrating sections 31 and the pair of connecting sections 4. In Figure 8(c), the width W11 is set smaller than in Figure 8(a). In Figure 8(d), the width W11 is set larger than in Figure 8(a). In all of Figures 8(a) to (d), the length L11 in Figure 6 is the same.

[0091] In Figure 8(c), the width W11 is smaller than in Figure 8(a), so the mass of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32) decreases, and the natural frequency of the first structure becomes higher than in Figure 8(a). As a result, in Figure 8(c), the position of the node S1 is shifted towards the pair of first folded parts 21 compared to the case of Figure 8(a). In this case, in the entire drive element 1, nodes S1 are generated not only in the second straight part 21c of the pair of first folded parts 21 (see Figure 6), but also in the second straight part 22c of the pair of second folded parts 22 (see Figure 6).

[0092] In Figure 8(d), the width W11 is larger than in Figure 8(a), which increases the mass of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32), and the natural frequency of the first structure becomes lower than in Figure 8(a). As a result, in Figure 8(c), the position of the node S1 is shifted towards the pair of first vibrating parts 31 compared to the case in Figure 8(a). In this case, the entire drive element 1 has nodes S1 near the base of the pair of first vibrating parts 31 as well as near the base of the pair of second vibrating parts 32.

[0093] Thus, in the configuration shown in Figure 6, the position of node S1 can be adjusted by adjusting the width W11.

[0094] As shown in Figures 7(a) to 7(d) and 8(a) to 8(d), in the configuration of Figure 6, the position of the node S1 can be adjusted not only by adjusting the length of the pair of first vibrating parts 31 and the pair of second vibrating parts 32, but also by adjusting the width of the mass adjustment parts 31a and 32a. Therefore, in the configuration of Figure 6, compared to the configuration of Embodiment 1 described above, by reducing the length of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 while adjusting the size of the mass adjustment parts 31a and 32a, a node S1 can be generated near the connection position between the pair of connecting parts 4 and the drive unit 3. This effectively suppresses vibrations in the pair of connecting parts 4 during the resonant operation of the movable part 2 in reverse phase mode.

[0095] In the configuration shown in Figure 6, the mass adjustment sections 31a and 32a are formed by widening the width of the ends of the pair of first vibrating sections 31 and the pair of second vibrating sections 32. However, the configuration for increasing the mass of the pair of first vibrating sections 31 and the pair of second vibrating sections 32 is not limited to this. For example, the mass adjustment sections 31a and 32a may be formed by increasing the thickness of the ends of the pair of first vibrating sections 31 and the pair of second vibrating sections 32, or the mass adjustment sections 31a and 32a may be formed by increasing both the width and thickness of the ends of the pair of first vibrating sections 31 and the pair of second vibrating sections 32. The increase in thickness can be achieved, for example, by laminating another layer on the lower surface, similar to the support structure 5 in Figure 2.

[0096] <Effects of Embodiment 2> According to the configuration of Embodiment 2, the same effects as those of Embodiment 1 can be generally achieved.

[0097] In addition, in Embodiment 2, as shown in Figure 6, the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are each equipped with mass adjustment parts 31a and 32a for adjusting their own mass.

[0098] With this configuration, the natural frequencies of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32) can be adjusted by adjusting the mass using the mass adjustment units 31a and 32a.

[0099] <Embodiment 3> Figure 9 is a schematic top view showing the configuration of the drive element 1 according to Embodiment 3.

[0100] As shown in Figure 9, in the drive element 1 according to Embodiment 3, the mass adjustment sections 31a and 32a are enlarged compared to the drive element 1 in Figure 6 according to Embodiment 2, and the lengths of the pair of first vibrating sections 31 and the pair of second vibrating sections 32 are shortened. In addition, in the drive element 1 according to Embodiment 3, the drive unit 3 side of each connection section 4 is divided into two rectangular sections, and at two positions on either side of the second axis A2, the two branched sections 4a of each connection section 4 are connected to the drive unit 3 (the pair of first vibrating sections 31 and the pair of second vibrating sections 32).

[0101] The other configurations of the drive element 1 according to Embodiment 3 are the same as those of Embodiment 2 described above. In Embodiment 3 as well, the structure consisting of the movable part 2, the drive unit 3, and the pair of connecting parts 4 has a shape that is symmetrical with respect to the first axis A1 and the second axis A2 in a plan view.

[0102] In the configuration of Embodiment 3, as in Embodiments 1 and 2, the movable part 2 can be repeatedly rotated around the first axis A1 by vibrating the pair of first vibrating parts 31 and the pair of second vibrating parts 32. In the configuration of Embodiment 3, the vibrations of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are propagated to the pair of first folded parts 21 and the pair of second folded parts 22 via the pair of connecting parts 41, causing the first support part 11 and the second support part 12 to repeatedly rotate in the same phase. As a result, the movable part 2 repeatedly rotates at a frequency corresponding to the vibration frequencies of the pair of first vibrating parts 31 and the pair of second vibrating parts 32.

[0103] In the configuration of Embodiment 3, the movable part 2 can be made to resonate in either in-phase or out-of-phase mode at the target frequency by adjusting the thickness and length of each part of the drive element 1. In this case as well, similar to Embodiments 1 and 2, by making the movable part 2 resonate in out-of-phase mode, vibrations generated in the drive element 1 near the connection point between the pair of connecting parts 4 and the drive unit 3 can be canceled out, and a node S1 can be generated near these connection points. As a result, vibration leakage to the pair of connecting parts 4 can be suppressed when the movable part 2 rotates, and the pair of connecting parts 4 can be kept in a state of almost no vibration.

[0104] Figure 10 shows the simulation results obtained by simulation when the movable part 2 of the drive element 1 according to Embodiment 3 is made to resonate. For convenience, the color simulation results are shown in grayscale in Figure 10 as well.

[0105] In this simulation, the drive element 1 is configured so that the movable part 2 rotates in reverse phase mode. Furthermore, the lengths of the pair of first vibrating parts 31 and the pair of second vibrating parts 32, as well as the widths of the mass adjustment parts 31a and 32a, are adjusted so that in reverse phase mode, nodes S1 are generated near the connection points between each connection part 4 (two branching parts 4a) and the drive unit 3 (a pair of first vibrating parts 31 and a pair of second vibrating parts 32). By adjusting the position of the nodes S1 in this way, vibrations in the pair of connection parts 4 during the rotational movement of the movable part 2 can be effectively suppressed, as shown in Figure 10.

[0106] Figure 11 is a schematic top view showing an example of the overall configuration of the drive element 1 according to Embodiment 3. Figure 12 is a schematic bottom view showing an example of the overall configuration of the drive element 1 according to Embodiment 3.

[0107] In the configuration example shown in Figure 11, the support structure 5 in Figure 9 includes other drive units 6 and a base 7.

[0108] The other drive units 6 are connected to the drive unit 3 and rotate the drive unit 3 about the second axis A2 in a plan view. The angle between the axis of rotation by the other drive units 6 and the first axis A1 may be slightly off from 90°. A pair of other drive units 6 are arranged on either side of the drive unit 3 in a direction parallel to the second axis A2. The base 7 is a frame-shaped member that supports the pair of other drive units 6. The drive element 1 has a symmetrical shape with respect to the center of the movable part 2.

[0109] The movable part 2 is rotated about the second axis A2 by the drive unit 3 being rotated about the second axis A2 by a pair of other drive units 6. The movable part 2 is rotated about the first axis A1 and the second axis A2 by the drive unit 3 and the other drive units 6, causing the light incident on the reflective surface 2c to be scanned in two dimensions.

[0110] Each of the other drive units 6 is a meander-type drive unit. Each of the other drive units 6 has four plate sections 61 connected in a meander manner. In plan view, each plate section 61 is a rectangle that is elongated in the direction parallel to the first axis A1. Another drive source 62 is positioned on the upper surface of each plate section 61. The other drive source 62, like the drive source 33, may be made of a piezoelectric material. The two innermost plate sections 61 are connected to one end of two connecting sections 63 at the ends away from the second axis A2. The other ends of the two connecting sections 63 are connected to a pair of connecting sections 4, respectively. The connecting sections 4 have a rectangular shape in plan view.

[0111] The pair of other drive units 6 and the base 7 share a common base material with the movable part 2, the drive unit 3, and the pair of connecting parts 4. An additional layer is laminated to the underside of the base material of the base 7, increasing its thickness. Similarly, the rib section 64 and connecting section 63, which connect the four plate sections 61 in a meander pattern, also have additional layers laminated to increase their thickness. In Figure 12, the areas where the additional layers are laminated are hatched.

[0112] Wiring for supplying drive signals to the two drive sources 33 and the eight drive sources 62 is arranged on the upper surface of the substrate between these drive sources and the base 7. Terminals connected to these wires are arranged on the upper surface of the substrate of the base 7. Similar to Embodiment 1 above, these wires and terminals may have the same layered structure as the drive sources 33 and 62. In addition, the lower electrodes of these wires are extended to the area of ​​the ground terminal on the base 7, forming a ground terminal.

[0113] In Figure 11, the first and third drive sources 62 from the positive X-axis side among the four other drive sources 62 on the positive X-axis side, and the second and fourth drive sources 62 from the negative X-axis side among the four other drive sources 62 on the negative X-axis side, are supplied with drive signals of the same polarity, while drive signals of the opposite polarity are supplied to the remaining four other drive sources 62. As a result, each of the other drive sources 62 is compressed or expanded in the Y-axis direction according to the polarity of the drive signal, and a driving force around the second axis A2 is supplied to the drive unit 3. In this way, the drive unit 3 rotates around the second axis A2, and consequently, the movable part 2 rotates around the second axis A2.

[0114] In the configuration examples shown in Figures 11 and 12, the structure of Embodiment 3 shown in Figure 9 is included in the drive element 1, but the structure of Embodiment 1 shown in Figure 1 or the structure of Embodiment 2 shown in Figure 6 may also be included in the drive element 1. Furthermore, the other drive unit 6 is not limited to the meander type drive unit shown in Figure 12, but may be a drive unit of another configuration, such as the capacitive type drive unit described in Japanese Patent Application Publication No. 2007-121464. The drive element 1 may be configured to include only one other drive unit 6, as long as the drive unit 3 can be rotated about a pivot axis intersecting the first axis A1.

[0115] Alternatively, the structure in Figure 9 may be supported by a support structure 5 similar to that in Figure 2, thereby forming the drive element 1. In this case, the drive element 1 causes the movable part 2 to repeatedly rotate only on the first axis A1, and scans the light incident on the reflective surface 2c in one dimension.

[0116] <Effects of Embodiment 3> The configuration of Embodiment 3 can also achieve generally the same effects as Embodiment 2.

[0117] In addition, in the configuration example shown in Figure 11, the drive element 1 includes, as a support structure 5, another drive unit 6 that rotates the drive unit 3 about another pivot axis (in this case, the second axis A2) that intersects the first axis A1.

[0118] With this configuration, the movable part 2 can be rotated around two intersecting axes (here, the first axis A1 and the second axis A2). Furthermore, vibrations generated by the resonant operation of the movable part 2 with respect to the first axis A1 are less likely to leak into the connection part 4, and the connection part 4 can be kept in a substantially stationary state. Therefore, even if a drive unit 6 with low rigidity is used as the support structure 5, the movable part 3 and the drive unit 3 can be rotated stably. In other words, the drive unit 3 can cause the movable part 2 to resonate around one axis (the first axis A1), while the other drive unit 6 can stably rotate the movable part 2 around the other axis (the second axis A2). Thus, the movable part 2 can be rotated stably around each axis.

[0119] Furthermore, in the configuration example shown in Figure 11, both sides of the drive unit 3 in the direction of the second axis A2 are connected to two connection points 4 at two positions that straddle the second axis A2.

[0120] With this configuration, compared to the case where both sides of the drive unit 3 are connected to the connection part 4 only at the position of the second axis A2, as shown in Embodiment 2 of Figure 6, the drive unit 3 can be rotated by other drive units more stably. As a result, when the drive unit is rotated by other drive units, it is possible to suppress the drive unit and movable parts from rotating beyond the intended position (overshoot), or to suppress the generation of unwanted vibrations in the drive unit and movable parts due to the reversal of rotational operation by other drive units.

[0121] <Embodiment 4> Figure 13 is a schematic top view showing the configuration of the drive element 1 according to Embodiment 4.

[0122] As shown in Figure 13, in the drive element 1 according to Embodiment 4, a pair of first vibrating parts 31 are connected to a pair of first folded parts 21 via a connecting part 41, and a pair of second vibrating parts 32 are connected to a pair of second folded parts 22 via a connecting part 41. The pair of first vibrating parts 31 and the pair of second vibrating parts 32 are connected to the pair of first folded parts 21 and the pair of second folded parts 22 at positions on the second axis A2 side of their respective inflection points P0. A drive source 33 is individually provided for the pair of first vibrating parts 31 and the pair of second vibrating parts 32. The pair of connecting parts 4 are connected to the drive unit 3 (second linear part 21c) at the position of the second axis A2.

[0123] The other configurations of the drive element 1 according to Embodiment 4 are the same as those of Embodiment 1. In Embodiment 4 as well, the structure consisting of the movable part 2, the drive unit 3, and the pair of connecting parts 4 has a shape that is symmetrical with respect to the first axis A1 and the second axis A2 in a plan view.

[0124] In the configuration of Embodiment 4, the movable part 2 can be repeatedly rotated around the first axis A1 by controlling the four drive sources 33 to vibrate the pair of first vibrating parts 31 and the pair of second vibrating parts 32 in the same manner as in Embodiments 1 and 2. In the configuration of Embodiment 4, the vibrations of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are propagated to the pair of first folded parts 21 and the pair of second folded parts 22, causing the first support part 11 and the second support part 12 to repeatedly rotate in the same phase. As a result, the movable part 2 repeatedly rotates around the first axis A1 at a frequency corresponding to the vibration frequencies of the pair of first vibrating parts 31 and the pair of second vibrating parts 32.

[0125] In the configuration of Embodiment 4, the movable part 2 can be made to resonate in either in-phase or out-of-phase mode at the target frequency by adjusting the thickness and length of each part of the drive element 1. In this case as well, by making the movable part 2 resonate in out-of-phase mode, vibrations generated in the drive element 1 near the connection point between the pair of connecting parts 4 and the drive unit 3 can be canceled out, and a node S1 can be generated near these connection points. This makes it possible to suppress vibration leakage to the pair of connecting parts 4 when the movable part 2 rotates.

[0126] Figure 14 shows the simulation results obtained by simulation when the movable part 2 is resonated in the drive element 1 according to Embodiment 4. For convenience, the color simulation results are shown in grayscale in Figure 14 as well.

[0127] In this simulation, the drive element 1 is configured so that the movable part 2 rotates in reverse phase mode. Furthermore, the lengths (masses) of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are adjusted so that nodes S1 occur near the connection points between each connection part 4 and the drive unit 3 in reverse phase mode. Here, the nodes S1 are set in the range from near the connection points between the first folded part 21 and the second folded part 22 and the two connecting parts 41 connected to them, to near the connection point between the pair of connection parts 4 and the drive unit 3. By adjusting the position of the nodes S1 in this way, vibrations in the pair of connection parts 4 can be suppressed when the movable part 2 rotates, as shown in Figure 14.

[0128] However, in this configuration, a region R1 of slight vibration occurs on the pair of connecting parts 4 during the resonant operation of the movable part 2. According to the inventor's simulations, even after adjusting various natural frequencies of the first structure (a pair of drive sources 33, a pair of first vibrating parts 31, and a pair of second vibrating parts 32) and the second structure (components of the drive unit 3 other than the first structure and the movable part 2), it was difficult to eliminate the vibration occurring on the pair of connecting parts 4.

[0129] Therefore, in order to ensure that the pair of connecting parts 4 vibrate almost completely when the movable part 2 is in resonant operation, it is preferable to connect the pair of first vibrating parts 31 and the pair of second vibrating parts 32 to the pair of first folded parts 21 and the pair of second folded parts 22 with the pair of connecting parts 41 near the second axis A2, as in the embodiments 1 to 3 described above.

[0130] In the configuration of Embodiment 4, as in Embodiment 2, mass adjustment units 31a and 32a may be arranged on a pair of first vibrating units 31 and a pair of second vibrating units 32. Also, in the configuration of Embodiment 4, as in Embodiment 3, the drive element 1 may be configured to include other drive units 6 and a base 7 as a support structure 5.

[0131] <Effects of Embodiment 4> The configuration of Embodiment 4 can also achieve generally the same effects as Embodiment 1.

[0132] However, in the configuration of Embodiment 4, as described above, a region R1 of slight vibration occurs in the connection part 4 during the resonant operation of the movable part 2. For this reason, in order to suppress such vibration, it is preferable that the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are connected to the pair of connection parts 4, respectively, as in Embodiments 1 to 3 above.

[0133] <Embodiment 5> Figure 15 is a schematic top view showing the configuration of the drive element 1 according to Embodiment 5.

[0134] As shown in Figure 15, the drive element 1 according to Embodiment 5 differs from the drive element 1 of Embodiment 1 in Figure 1 in the configuration of the pair of first folded portions 21 and the pair of second folded portions 22. Specifically, each of the pair of first folded portions 21 has only a curved portion 21e and a straight portion 21f, and each of the pair of second folded portions 22 has only a curved portion 22e and a straight portion 22f. Therefore, each of the pair of first folded portions 21 does not have an inflection point P0, and each of the pair of second folded portions 22 does not have an inflection point P0.

[0135] The other configurations of the drive element 1 according to Embodiment 5 are the same as those of Embodiment 1. In Embodiment 5 as well, the structure consisting of the movable part 2, the drive unit 3, and the pair of connecting parts 4 has a shape that is symmetrical with respect to the first axis A1 and the second axis A2 in a plan view.

[0136] In the configuration of Embodiment 5, the drive source 33 is controlled to vibrate the pair of first vibrating parts 31 and the pair of second vibrating parts 32 in the same manner as in Embodiment 1, thereby causing the movable part 2 to repeatedly rotate around the first axis A1. In the configuration of Embodiment 5, the vibrations of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 are propagated to the pair of first folded parts 21 and the pair of second folded parts 22, causing the first support part 11 and the second support part 12 to repeatedly rotate in the same phase. As a result, the movable part 2 repeatedly rotates around the first axis A1 at a frequency corresponding to the vibration frequencies of the pair of first vibrating parts 31 and the pair of second vibrating parts 32.

[0137] In the configuration of Embodiment 5, the movable part 2 can be made to resonate in either in-phase or out-of-phase mode at the target frequency by adjusting the thickness and length of each part of the drive element 1. In this case as well, by making the movable part 2 resonate in out-of-phase mode, vibrations generated in the drive element 1 near the connection point between the pair of connection parts 4 and the drive unit 3 can be canceled out, and vibration leakage to the pair of connection parts 4 during the rotational operation of the movable part 2 can be suppressed.

[0138] Figures 16(a), (b) and 17(a), (b) show the simulation results obtained by simulation when the movable part 2 is resonated in the drive element 1 according to Embodiment 5. For convenience, the color simulation results are shown in grayscale in these figures as well.

[0139] The upper sections of Figures 16(a), (b) and 17(a), (b) show the simulation results for the positive Y-axis range of the drive element 1. The lower sections of Figures 16(a), (b) and 17(a), (b) show the positive X-axis range of the simulation results in the upper sections of Figures 16(a), (b) and 17(a), (b), viewed from the negative Y-axis side.

[0140] In the simulations shown in Figures 16(a), (b) and 17(a), (b), the driving element 1 is configured to resonate in an inverse phase mode. The length of the pair of first vibrating sections 31 is largest in Figure 16(a) and gradually decreases in the order of Figures 16(b), 17(a), and 17(b).

[0141] In the simulation shown in Figure 16(a), a node S1 is formed at a position slightly shifted from the base to the tip of the pair of first vibrating sections 31, while in the simulation shown in Figure 16(b), a node S1 is formed near the base of the pair of first vibrating sections 31. Furthermore, in the simulation shown in Figure 17(a), a node S1 is formed near the joint position between the pair of first vibrating sections 31 and the pair of connecting sections 4, while in the simulation shown in Figure 17(b), a node S1 is formed near the joint position between the pair of connecting sections 41 and the pair of first folded sections 21.

[0142] Referring to these simulation results, the vibrations generated in the pair of connecting parts 4 during the resonant operation of the movable part 2 are most suppressed in the case shown in Figure 16(b). However, the node S1 that occurs in this case is not parallel to the direction in which the pair of connecting parts 4 extend (X-axis direction), as shown by the dashed line in Figure 16(b), but is tilted with respect to this direction. Therefore, in this case, twisting occurs around the Y-axis near the base of the pair of first vibrating parts 31, and this twisting causes distortion in the connecting part 4 in the Z-axis direction, as schematically shown by the dashed line in the lower part of Figure 16(b). In the cases of Figures 16(a), 17(a), and (b), as schematically shown by the dashed lines in the lower part of these figures, distortion in the Z-axis direction occurs in the connecting part 4 during the resonant operation of the movable part 2. These distortions indicate that vibrations occur in the pair of connecting parts 4 during the resonant operation of the movable part 2.

[0143] Thus, in the configuration of Figure 15, although vibration leakage to the pair of connecting parts 4 can be suppressed by resonating the movable part 2 in reverse phase mode, it is difficult to set the pair of connecting parts 4 to a state where they vibrate almost completely, as in embodiments 1 to 3 described above. According to the inventors' investigation, such differences in vibration suppression may arise depending on whether or not the first folded part 21 and the second folded part 22 have an inflection point P0.

[0144] In other words, when the movable part 2 rotates around the first axis A1, twisting occurs in the first support part 11 and the second support part 12 around the first axis A1. This twisting propagates to the pair of first folded parts 21 and the pair of second folded parts 22. Here, as in Embodiment 5 of Figure 15, if the first folded parts 21 and the second folded parts 22 do not have an inflection point P0, this twisting propagates through the first folded parts 21 and the second folded parts 22 and reaches the connecting part 41 and the joint part 4. For this reason, in the configuration of Figure 15, as shown in the simulation results of Figures 16(a), (b) and 17(a), (b), strain (vibration) based on this twisting occurs in the joint part 4.

[0145] In contrast, as in embodiments 1 to 3 above, when the first folded portion 21 and the second folded portion 22 do not have an inflection point P0, the twist generated in the first support portion 11 and the second support portion 12 propagates to the range of the first folded portion 21 and the second folded portion 22 from the curved portions 21a and 22a to the vicinity of the inflection point P0, but does not propagate to the range of the second straight portions 21c and 22c after passing the vicinity of the inflection point P0. That is, during the resonant operation of the movable portion 2, the second straight portions 21c and 22c vibrate substantially only in the Z-axis direction. For this reason, in the configurations of embodiments 1 to 3 above, for example, as shown in Figures 7(c) and (d), the direction of the node S1 is parallel to the direction in which the connecting portion 4 extends, and the twist generated in the first support portion 11 and the second support portion 12 does not substantially propagate to the connecting portion 4.

[0146] Therefore, in the configurations of embodiments 1 to 3 described above, the pair of connecting parts 4 can be set to a state where they vibrate almost completely by adjusting the position of the node S1 that occurs when the movable part 2 is resonated in reverse phase mode, as described above. Thus, in order to more reliably suppress vibration leakage to the pair of connecting parts 4, it is preferable to set the shapes of the pair of first folded parts 21 and the pair of second folded parts 22 such that the pair of first folded parts 21 and the pair of second folded parts 22 have an inflection point P0, as in embodiments 1 to 3 described above.

[0147] <Effects of Embodiment 5> As shown in Figures 16(a), (b) and 17(a), (b), in Embodiment 5 as well, the movable part 2 can be repeatedly rotated around the first axis A1 by vibrating the pair of first vibrating parts 31 and the pair of second vibrating parts 32 with the pair of drive sources 33.

[0148] However, as described above, in the configuration of Embodiment 5, when the movable part 2 resonates, the twist of the first support part 11 and the second support part 12 is transmitted to the pair of connecting parts 4, which can cause strain (vibration) in these connecting parts 4. Therefore, in order to suppress such strain (vibration) and set these connecting parts 4 to a nearly stationary state, it is preferable that the pair of first folded parts 21 and the pair of second folded parts 22 each have a shape with an inflection point P0, as in Embodiments 1 to 4 above.

[0149] Although embodiments 1 to 5 have been presented above as examples of the present invention, the embodiments of the present invention are not limited to these, and various modifications are possible.

[0150] <Example of change 1> Figure 18 is a schematic top view showing the configuration of the drive element 1 according to modification example 1.

[0151] As shown in Figure 18, in Modification Example 1, compared to the configuration of Embodiment 3 shown in Figure 9, two monitor elements 34, which output signals corresponding to the rotational movement of the movable part 2, are arranged across the pair of first vibrating parts 31 and the pair of second vibrating parts 32 in the Y-axis direction. The central part of the drive source 33 in the Y-axis direction is cut out so as to be recessed inward. The monitor elements 34 are arranged in this cut-out region. The monitor elements 34 are made of piezoelectric material, similar to the drive source 33.

[0152] One end of each of the four connection parts 4 is connected to two positions on either side of the drive unit 3, flanking the second axis A2, in the direction of the second axis A2, similar to the branching portion 4a in Figure 9. The other ends of the four connection parts 4 are connected to the support structure 5. The support structure 5 has the same configuration as in the embodiment 1 described above.

[0153] Terminals T0, T1, and T2 are located on the upper surfaces of two straight sections of the support structure 5, which are aligned in the X-axis direction. Terminal T0 is the ground terminal, and terminal T1 is a terminal for supplying a drive signal to the drive source 33. Terminal T1 is a terminal for outputting a detection signal from the monitor element 34. Terminal T1 is connected to the drive source 33 by wiring L1, and terminal T2 is connected to the monitor element 34 by wiring L2. Wiring L1 for the drive source 33 is located in one of the two connection parts 4 aligned in the Y-axis direction, and wiring L2 for the monitor element 34 is located in the other of these two connection parts 4.

[0154] The wirings L1 and L2 and terminals T1 and T2 may have a layered structure similar to that of the piezoelectric material constituting the drive source 33 and the monitor element 34. The lower electrodes of the wirings L1 and L2 may be extended to the area of ​​the ground terminal, becoming the ground terminal T0. The other configurations of Modification Example 1 are the same as those in Figure 9.

[0155] With this configuration, the rotational movement (rotation period, etc.) of the movable part 2 can be monitored by the output from the monitoring element 34, and the drive signal of the drive source 33 can be controlled to obtain the desired rotational movement. In addition, since the wiring L1 for the drive source and the wiring L2 for the monitoring element are located at different connection points 4, each wire can be easily and smoothly arranged.

[0156] Note that the position of the monitor element 34 is not limited to the position shown in Figure 18, but may be in other positions as long as it can output a signal corresponding to the rotational movement of the movable part 2. For example, the monitor element 34 may be positioned across the second linear sections 21c and 22c aligned in the Y-axis direction. In this case, in order to route the wiring L2 from the monitor element 34 to terminal T2, the drive source 33 is separated in the Y-axis direction near the second axis A2, and a gap is provided between the separated drive sources 33.

[0157] Monitor elements 34 may be arranged in the configurations of embodiments 1, 2, 4, and 5 described above. For example, in the configuration of embodiment 1, the pair of drive sources 33 may be modified to the same shape as in Figure 18, and the pair of monitor elements 34 may be arranged. In this case, the respective wiring of each drive source 33 and monitor element 34 can be routed through the region of the first vibration section 31 or the second vibration section 32 where the drive source 33 and monitor element 34 are not arranged, and through the connection section 4 to the support structure 5.

[0158] Furthermore, since the area of ​​the monitor element 34 is small, it is unlikely to affect the resonant operation of the movable part 2. For this reason, the arrangement of the monitor element 34 does not necessarily have to be symmetrical with respect to the first axis A1 and the second axis A2; for example, one of the pair of monitor elements 34 may be omitted. In this case, the structure consisting of the movable part 2, the drive unit 3, and the multiple connection parts 4 has a shape that is substantially symmetrical with respect to the first axis A1 and the second axis A2 in a plan view.

[0159] <Example of change 2> The configuration of the movable part 2 can be modified in various ways other than those described in embodiments 1 to 5 above.

[0160] Figure 19(a) is a schematic top view showing the configuration of the drive element 1 according to modification example 2.

[0161] Compared to Embodiment 1 in Figure 1, in Modified Example 2, the frame portion 2b is omitted from the movable portion 2, and the movable portion 2 is composed only of the driven portion 2a. The other configurations of the drive element 1 in Modified Example 2 are the same as those in Embodiment 1. In Embodiments 2 to 5, the configuration of the movable portion 2 can also be changed in the same way as in Figure 19(a).

[0162] In the configuration shown in Figure 19(a), compared to the case where the frame portion 2b is arranged, distortion is more likely to occur in the movable portion 2 and the reflective surface 2c during the resonant operation of the movable portion 2, and the beam profile of the light reflected by the reflective surface 2c is more likely to deteriorate. For this reason, in this configuration, for example, ribs to suppress the distortion of the movable portion 2 may be arranged on the lower surface of the movable portion 2.

[0163] <Example of change 3> The configuration of the mass adjustment unit can be modified in various ways other than the configurations of embodiments 2 and 3 described above.

[0164] Figure 19(b) is a schematic top view showing the configuration of the drive element 1 according to modification example 3.

[0165] In Figure 9, the ends of the pair of first vibrating parts 31 and the ends of the pair of second vibrating parts 32 are widened in the direction approaching the first axis A1, and the mass adjustment parts 31a and 32a are arranged therein. However, in modified example 3 of Figure 19(b), the ends of the pair of first vibrating parts 31 and the ends of the pair of second vibrating parts 32 are widened in the direction approaching the first axis A1 as well as in the direction away from the first axis A1, and the mass adjustment parts 31a, 31b, 32a, and 32b are arranged therein. The other configurations of the drive element 1 in modified example 3 are the same as those of embodiment 3 described above.

[0166] In modification example 3, since the mass adjustment sections 31b and 32b are located outside the pair of first vibrating sections 31 and the pair of second vibrating sections 32, the drive unit 3 becomes larger in the direction of the second axis A2 compared to embodiment 3. On the other hand, since the mass adjustment sections 31a, 32a and 31b, 32b are arranged both inside and outside the pair of first vibrating sections 31 and the pair of second vibrating sections 32, the mass of the pair of first vibrating sections 31 and the pair of second vibrating sections 32 can be smoothly increased, and the size and arrangement of the mass adjustment sections 31a, 31b, 32a, and 32b can be easily adjusted to adjust the position of the node S1. In addition, the symmetry of the mass is improved in each of the pair of first vibrating sections 31 and the pair of second vibrating sections 32, making it easier to suppress vibrations in directions other than the Z axis.

[0167] In Figure 19(b), the mass adjustment sections 31a and 31b located on one first vibrating section 31 are symmetrical in the X-axis direction, and the mass adjustment sections 32a and 32b located on one second vibrating section 32 are symmetrical in the X-axis direction. However, the shapes of the mass adjustment sections 31a, 31b, 32a, and 32b are not limited to these. For example, the widths of the mass adjustment sections 31a and 31b may differ from each other, and the widths of the mass adjustment sections 32a and 32b may differ from each other. In this case as well, the structure consisting of the movable section 2, the drive unit 3, and the pair of connecting sections 4 only needs to have a shape that is symmetrical with respect to the first axis A1 and the second axis A2 in a plan view.

[0168] <Examples of changes 4 and 5> The configuration of the first folded portion 21 and the second folded portion 22 is not limited to the configurations of embodiments 1 to 4 described above, and various modifications are possible.

[0169] Figures 20(a) and 20(b) are schematic top views showing the configuration of the drive element 1 according to modification examples 4 and 5, respectively.

[0170] In the modified example 4 shown in Figure 20(a), the first straight section 21b of the first folded section 21 is not parallel to the first axis A1, but is tilted so as it approaches the second axis A2, it approaches the first axis A1. Similarly, the first straight section 22b of the second folded section 22 is not parallel to the first axis A1, but is tilted so as it approaches the second axis A2, it approaches the first axis A1. Because the first straight sections 21b and 22b are tilted in this way, the lengths of the intermediate sections 21d and 22d are larger compared to the embodiment 1 shown above. The other configurations of the drive element 1 in modified example 4 are the same as those of the embodiment 1 shown in Figure 1.

[0171] In Modification Example 5 shown in Figure 20(b), the second straight section 21c of the first folded section 21 is not parallel to the first axis A1, but is tilted so as it moves away from the second axis A2 it approaches the first axis A1. Similarly, the second straight section 22c of the second folded section 22 is not parallel to the first axis A1, but is tilted so as it moves away from the second axis A2 it approaches the first axis A1. Because the second straight sections 21c and 22c are tilted in this way, the lengths of the second straight sections 21c and 22c are larger, and the lengths of the intermediate sections 21d and 22d are smaller compared to Embodiment 1. The other configurations of the drive element 1 in Modification Example 5 are the same as those of Embodiment 1 shown in Figure 1.

[0172] In the configurations shown in Figures 20(a) and (b), the structure consisting of the movable part 2, the drive unit 3, and the pair of connecting parts 4 has a symmetrical shape with respect to the first axis A1 and the second axis A2 in a plan view. In these configurations as well, since the first folded part 21 and the second folded part 22 have an inflection point P0, the propagation of the twist of the first support part 11 and the second support part 12 to the second straight parts 21c and 22c during the resonant operation of the movable part 2 can be suppressed. Therefore, by setting the position of the node S1 generated by the resonance of the movable part 2 in the reverse-phase mode near the joint position between the drive unit 3 and the pair of connecting parts 4, vibration leakage to the pair of connecting parts 4 can be effectively suppressed, and the pair of connecting parts 4 can be kept in a state of almost no vibration during the resonant operation of the movable part 2.

[0173] In embodiments 2 to 4, the configuration of the pair of first folded portions 21 and the pair of second folded portions 22 can be changed in the same manner as in Figures 20(a) and (b).

[0174] <Examples of changes 6 and 7> The configuration of the connecting portion 41 that connects the pair of first vibrating portions 31 and the pair of second vibrating portions 32 to the pair of first folded portions 21 and the pair of second folded portions 22 is not limited to the configurations of embodiments 1 to 5 described above, and various modifications are possible.

[0175] Figures 21(a) and 21(b) are schematic top views showing the configuration of the drive element 1 according to modification examples 6 and 7, respectively.

[0176] In the modified example 6 shown in Figure 21(a), two connecting parts 41 are positioned at two locations on either side of the second axis A2. A pair of first vibrating parts 31 are connected to a pair of first folded parts 21 via two connecting parts 41 on the positive side of the Y-axis, and a pair of second vibrating parts 32 are connected to a pair of second folded parts 22 via two connecting parts 41 on the negative side of the Y-axis. The other configurations of the drive element 1 in modified example 6 are the same as those of embodiment 1 shown in Figure 1.

[0177] In modification example 7 of Figure 21(b), the pair of connecting parts 4 in the configuration of modification example 6 of Figure 21(a) are replaced with the pair of connecting parts 4 in the configuration of Figure 9. The two branch portions 4a of the connecting part 4 on the positive X-axis side are in approximately the same position as the two connecting parts 41 on the positive X-axis side in the Y-axis direction, and the two branch portions 4a of the connecting part 4 on the negative X-axis side are in approximately the same position as the two connecting parts 41 on the negative X-axis side in the Y-axis direction.

[0178] In the configurations shown in Figures 21(a) and (b), the structure consisting of the movable part 2, the drive unit 3, and the pair of connecting parts 4 has a symmetrical shape with respect to the first axis A1 and the second axis A2 in a plan view. In these configurations as well, by setting the position of the node S1 near the joining position between each branching part 4a and the drive unit 3, and more specifically near the joining position between each connecting part 41 and the first vibrating part 31 and the second vibrating part 32, it is possible to effectively suppress the leakage of vibration to the pair of connecting parts 4 during the resonant operation of the movable part 2.

[0179] In embodiments 2 and 3, the configuration of the pair of first folded portions 21 and the pair of second folded portions 22 can be changed in the same manner as in Figures 21(a) and (b).

[0180] <Examples of changes 8 and 9> The configuration of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 is not limited to the configurations of embodiments 1 to 5 described above, and various modifications are possible.

[0181] For example, as shown in Modification Example 8 of Figure 22(a), the pair of first vibrating parts 31 and the pair of second vibrating parts 32 may be arranged at an angle such that they move away from the second axis A2 and approach the first axis A1, and the drive sources 33 for each of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 may be arranged individually. Alternatively, as shown in Modification Example 9 of Figure 22(b), a common drive source 33 may be arranged for the first vibrating parts 31 and the second vibrating parts 32 that are aligned in the Y-axis direction. The other configurations of the drive element 1 according to Modification Examples 8 and 9 are the same as the configuration of Embodiment 1 shown in Figure 1.

[0182] In the configurations shown in Figures 22(a) and (b), the structure consisting of the movable part 2, the drive unit 3, and the pair of connecting parts 4 has a symmetrical shape with respect to the first axis A1 and the second axis A2 in a plan view. In these configurations as well, by setting the position of the node S1 near the joining position between the pair of connecting parts 4 and the drive unit 3, it is possible to effectively suppress the leakage of vibration to the pair of connecting parts 4 during the resonant operation of the movable part 2.

[0183] The same modifications as those shown in Figures 22(a) and (b) may be made to embodiments 2 to 5 described above. Furthermore, the pair of first vibrating parts 31 and the pair of second vibrating parts 32 may be arranged at an angle such that they move away from the first axis A1 as they move away from the second axis A2. However, in this case, the shape of the drive element 1 becomes slightly larger in the X-axis direction. Also, each of the pair of first vibrating parts 31 and the pair of second vibrating parts 32 does not necessarily have to extend in a straight line; they may include bent or curved shapes. The pair of first vibrating parts 31 and the pair of second vibrating parts 32 can be changed to various shapes insofar as they can cause the movable part 2 to repeatedly rotate due to vibration in the Y-axis direction.

[0184] <Other examples of changes> In embodiments 1 to 3 and 5 described above, a common drive source 33 was provided for the first vibrating section 31 and the second vibrating section 32, which are aligned in the Y-axis direction. However, the drive source 33 may be provided individually for the first vibrating section 31 and the second vibrating section 32.

[0185] In Embodiment 3 of Figure 9, two branch sections 4a (connecting sections) are connected to the drive unit 3 in the X-axis direction at two positions flanking the second axis A2. However, three or more connecting sections may be connected to each side of the drive unit 3. In this case as well, the structure consisting of the movable section 2, the drive unit 3, and these connecting sections has a symmetrical shape with respect to the first axis A1 and the second axis A2 in a plan view. For example, in each connecting section 4 of Figure 9, an additional branch section may be added at an intermediate position between the two branch sections 4a, and this branch section may be connected to the drive unit 3 at the position of the second axis A2.

[0186] In embodiments 2 to 4 described above, the position of the node S1 was adjusted so that vibration leakage to each connection part 4 is suppressed in the reverse-phase mode. However, for example, in embodiments 2 to 4, if a highly rigid support structure 5 as shown in Figure 2 is used and there is no need to suppress vibration leakage to the connection part 4 to that extent, the position of the node S1 does not need to be adjusted as described above.

[0187] In embodiments 1 to 5 described above, since the movable part 2 includes a frame part 2b, no ribs for distortion suppression were placed on the lower surface of the driven part 2a. However, even when the movable part 2 includes a frame part 2b, ribs may be placed on the lower surface of the driven part 2a. For example, if the thickness of the base material of the driven part 2a is reduced to be less than the thickness of the base material of the frame part 2b and the drive unit 3 in order to reduce weight, it is conceivable that distortion may occur in the driven part 2a during the resonant operation of the movable part 2. In this case, for example, when reducing the thickness of the base material of the driven part 2a from the lower side, the thickness of the rib portion can be left as is, without reducing the thickness of the original base material. This makes it possible to reduce the thickness of the driven part 2a while placing ribs for distortion suppression on the lower surface of the driven part 2a.

[0188] The shape and contour of the frame portion 2b are not limited to the shapes shown in embodiments 1 to 5 above, but may be other shapes and contours. The shape of the support structure 5 is also not limited to the shape shown in Figure 2, but may be, for example, a shape that encloses the entire circumference of the drive unit 3 in a rectangle in a plan view. The configurations in Figures 11 and 12 may be applied to the configurations of embodiments 1 and 2.

[0189] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims.

[0190] (Note) The above description of embodiments discloses the following technologies.

[0191] (Technology 1) Movable parts and A drive unit that rotates the movable part about the first axis, In a plan view, the drive unit is connected to the support structure from both sides near the second axis which is perpendicular to the first axis, and comprises a plurality of connection parts. The structure comprising the movable part, the drive unit, and the plurality of connecting parts has a shape that is substantially symmetrical with respect to the first axis and the second axis in a plan view. The aforementioned drive unit is A first support portion extending from the movable portion along the first axis, A second support portion extends from the movable portion in the direction opposite to the first support portion, A pair of first folded portions branching from the end of the first support portion and reaching the second axis, A pair of second folded portions branching from the end of the second support portion and leading to the second axis, A pair of first vibrating parts are connected to each of the pair of first folded parts and extend at least in a direction away from the second axis, A pair of second vibrating parts are connected to each of the pair of the second folded parts and extend at least in a direction away from the second axis, The system comprises at least a pair of drive sources arranged in the pair of first vibrating parts and the pair of second vibrating parts, which vibrate these vibrating parts in directions perpendicular to the first and second axes, The pair of first folded portions and the pair of second folded portions are connected to each other on the second axis. A driving element characterized by the following features.

[0192] According to this technology, the vibration energy of a pair of first vibrating parts and a pair of second vibrating parts is applied to the movable part from both sides via the first and second folded parts and the first and second support parts, causing the movable part to resonate around the first axis. Therefore, the movable part can be rotated repeatedly in a stable and efficient manner. Furthermore, the configuration for rotating the movable part, namely two sets, each having a first vibrating part and a second vibrating part on which a drive source is located, are arranged to sandwich the movable part in the direction of the second axis. As a result, the shape of the drive element in the direction of the first axis can be significantly suppressed, and the shape of the drive element can be made more compact. Therefore, the drive element according to this technology can stably drive the movable part while achieving a smaller external size.

[0193] (Technology 2) In the driving element described in Technology 1, One and the other of the pair of first vibrating parts, and one and the other of the pair of second vibrating parts, are each connected to each other on the second axis. A common drive source is provided for the first vibrating section and the second vibrating section, which are connected to each other. A driving element characterized by the following features.

[0194] This technology allows for increased lengths of the first and second vibrating sections and the drive source, enabling efficient driving of the movable part. Furthermore, since a common drive source is provided for the interconnected first and second vibrating sections, the drive source configuration can be simplified, reducing the number of wires connected to the drive source. The movable part can be driven by applying only two types of vibrations with opposite phases to each of the drive sources separated in the second axial direction.

[0195] (Technology 3) In the driving element described in Technology 1 or 2, The drive unit is configured such that, at the target frequency, the movable part performs a resonant operation around the first axis in opposite phase with respect to the pair of first vibrating parts and the pair of second vibrating parts. A driving element characterized by the following features.

[0196] According to this technology, at the target frequency, the movable part resonates in opposite phase with respect to a pair of first vibrating parts and a pair of second vibrating parts. As a result, vibrations generated in the drive unit during this resonant operation cancel each other out. Therefore, unwanted vibrations generated during the resonant operation of the movable part can be effectively suppressed.

[0197] (Technology 4) In the driving element described in Technology 3, Each of the pair of first folded portions and the pair of second folded portions has a shape that includes an inflection point. The pair of first vibrating parts and the pair of second vibrating parts are connected to the pair of first folded parts and the pair of second folded parts at a position on the second axis side of the respective inflection point. A driving element characterized by the following features.

[0198] This technology makes it possible to suppress the propagation of torsion generated in the first and second support parts during the resonant operation of the movable part to the connection part. Specifically, in the range from the inflection point towards the movable part of the pair of first and second folded parts, torsion occurs in accordance with the torsion of the first and second support parts, but in the range from the inflection point towards the second axis, vibration occurs mainly in a direction perpendicular to the first and second axes due to vibrations from the first and second vibrating parts. In other words, the propagation of torsion generated in the first and second support parts to the range of the first and second folded parts on the second axis side of their respective inflection points is suppressed. Therefore, it is possible to suppress the generation of torsion in each connection part during the resonant operation of the movable part.

[0199] (Technology 5) In the driving element described in Technology 4, The natural frequencies of the first structure, which consists of at least one pair of drive sources, a pair of first vibrating parts, and a pair of second vibrating parts, and the natural frequencies of the second structure, which consists of the components of the drive unit other than the first structure and the movable parts, are adjusted so that the position of the node where the direction of vibration resulting from the anti-phase resonance operation switches is near the connection position between the multiple connection parts and the drive unit. A driving element characterized by the following features.

[0200] This technology suppresses the transmission of vibrations generated during the resonant operation of the movable part to the connection point, thereby maintaining the connection point in a virtually vibration-free state. As a result, it is possible to suppress vibration leakage from the connection point to the support structure, and the movable part can operate stably even if the rigidity of the connection point and support structure is low.

[0201] (Technology 6) In the driving element described in Technology 4 or 5, Each of the pair of first vibrating parts and the pair of second vibrating parts is equipped with a mass adjustment part for adjusting its own mass. A driving element characterized by the following features.

[0202] This technology allows the natural frequency of the first structure to be adjusted by adjusting the mass using the mass adjustment unit. Furthermore, the required mass can be secured even if the first vibrating section is short, and the shape of the drive element can be made more compact.

[0203] (Technology 7) In the driving element described in any of Technical 4 to 6, The support structure includes another drive unit that rotates the drive unit about another pivot axis intersecting the first axis. A driving element characterized by the following features.

[0204] This technology allows the movable part to rotate around two intersecting axes. Furthermore, vibrations generated by the resonant movement of the movable part relative to the first axis are less likely to leak into the connection point, and the connection point can be kept in a substantially stationary state. As a result, the movable part can be made to resonate around one axis by one drive unit, while the other drive unit stably rotates the movable part around the other axis. Therefore, the movable part can be stably rotated around each axis.

[0205] (Technology 8) In the driving element described in Technology 7, Both sides of the drive unit in the direction of the second axis are connected to a plurality of connection points at at least two positions that straddle the second axis. A driving element characterized by the following features.

[0206] This technology allows the drive unit to be rotated by other drive units more stably compared to a case where both sides of the drive unit are connected to the connection point only at the position of the second axis. As a result, it is possible to suppress the drive unit and movable parts from rotating beyond their intended position (overshoot) when rotated by other drive units, or to suppress the generation of unwanted vibrations in the drive unit and movable parts due to the reversal of rotational movements by other drive units.

[0207] (Technology 9) In the driving element described in Technical 8, The pair of first vibrating parts and the pair of second vibrating parts are connected to each other on the second axis, The first vibrating part and the second vibrating part, which are connected to each other, are equipped with a drive source for driving the first vibrating part and the second vibrating part, and a monitor element that outputs a signal corresponding to the rotational movement of the movable part. Wiring for the drive source is arranged in one of the multiple connection parts, and wiring for the monitor element is arranged in another of the multiple connection parts. A driving element characterized by the following features.

[0208] This technology allows monitoring of the rotational movement (such as the repetitive rotation cycle) of the movable part via the output from the monitoring element, and enables control of the drive signal of the drive source to achieve the desired rotational movement. Furthermore, since the wiring for the drive source and the wiring for the monitoring element are located at different connection points, the respective wiring can be easily and smoothly arranged.

[0209] (Technology 10) In the driving element described in any of Technology 1 to 9, The aforementioned movable part is The driven part and, In a plan view, it consists of a frame that surrounds the driven part and is connected to the driven part near the position of the driven part furthest from the first axis, The first support portion and the second support portion are connected to the frame portion. A driving element characterized by the following features.

[0210] According to this technology, the area of ​​the driven part furthest from the first axis (the pivot axis), i.e., the area of ​​the driven part most susceptible to distortion during rotation, is supported by the frame, and driving force is applied to this end from the first and second support parts. Therefore, distortion of the driven part can be effectively suppressed during the rotational movement of the movable part.

[0211] (Technology 11) In the driving element described in any of Technology 1 to 10, The movable part has a reflective surface, A driving element characterized by the following features.

[0212] This technology allows the driving element to be used as an optical deflector. [Explanation of Symbols]

[0213] 1. Driving element 2 Moving parts 2a Driven part 2b Frame 2c reflective surface 3. Drive Unit 4 Connection part 5 Support structure 6 Other drive units 7 base 11 First support part 12 Second support part 21 First Folding Section 22 Second Folding Section 31 First Vibration Section 32 Second Vibration Section 31a, 32a Mass adjustment section 33 Power source A1 First Axis A2 2nd axis L1, L2 wiring P0 inflection point

Claims

1. Movable parts and A drive unit that rotates the aforementioned movable part about the first axis, In a plan view, the drive unit is connected to the support structure from both sides near the second axis which is perpendicular to the first axis, and comprises a plurality of connection parts. The structure comprising the movable part, the drive unit, and the plurality of connecting parts has a shape that is substantially symmetrical with respect to the first axis and the second axis in a plan view. The aforementioned drive unit is A first support portion extending from the movable portion along the first axis, A second support portion extends from the movable portion in the direction opposite to the first support portion, A pair of first folded portions branching from the end of the first support portion and reaching the second axis, A pair of second folded portions branching from the end of the second support portion and reaching the second axis, A pair of first vibrating parts are connected to each of the pair of first folded parts and extend at least in a direction away from the second axis, A pair of second vibrating parts are connected to each of the pair of the second folded parts and extend at least in a direction away from the second axis, The system comprises at least a pair of drive sources arranged in the pair of first vibrating parts and the pair of second vibrating parts, which vibrate these vibrating parts in directions perpendicular to the first and second axes, The pair of first folded portions and the pair of second folded portions are connected to each other on the second axis. A driving element characterized by the following features.

2. In the drive element according to claim 1, One and the other of the pair of first vibrating parts, and one and the other of the pair of second vibrating parts, are each connected to each other on the second axis. A common drive source is provided for the first vibrating section and the second vibrating section, which are connected to each other. A driving element characterized by the following features.

3. In the drive element according to claim 1, The drive unit is configured such that, at the target frequency, the movable part performs a resonant operation around the first axis in opposite phase with respect to the pair of first vibrating parts and the pair of second vibrating parts. A driving element characterized by the following features.

4. In the drive element according to claim 3, Each of the pair of first folded portions and the pair of second folded portions has a shape that includes an inflection point. The pair of first vibrating parts and the pair of second vibrating parts are connected to the pair of first folded parts and the pair of second folded parts at a position on the second axis side of the respective inflection point. A driving element characterized by the following features.

5. In the drive element according to claim 4, The natural frequencies of the first structure, which consists of at least one pair of drive sources, a pair of first vibrating parts, and a pair of second vibrating parts, and the natural frequencies of the second structure, which consists of the components of the drive unit other than the first structure and the movable parts, are adjusted so that the position of the node where the direction of vibration resulting from the anti-phase resonance operation switches is near the connection position between the multiple connection parts and the drive unit. A driving element characterized by the following features.

6. In the drive element according to claim 4, Each of the pair of first vibrating parts and the pair of second vibrating parts is equipped with a mass adjustment part for adjusting its own mass. A driving element characterized by the following features.

7. In the drive element according to claim 5, The support structure includes another drive unit that rotates the drive unit about another pivot axis intersecting the first axis. A driving element characterized by the following features.

8. In the drive element according to claim 7, Both sides of the drive unit in the direction of the second axis are connected to a plurality of connection points at at least two positions that straddle the second axis. A driving element characterized by the following features.

9. In the driving element according to claim 8, The pair of first vibrating parts and the pair of second vibrating parts are connected to each other on the second axis, The first vibrating part and the second vibrating part, which are connected to each other, are equipped with a drive source for driving the first vibrating part and the second vibrating part, and a monitor element that outputs a signal corresponding to the rotational movement of the movable part. Wiring for the drive source is arranged in one of the multiple connection parts, and wiring for the monitor element is arranged in another of the multiple connection parts. A driving element characterized by the following features.

10. In the drive element according to claim 1, The aforementioned movable part is The driven part and, In a plan view, it consists of a frame that surrounds the driven part and is connected to the driven part near the position of the driven part furthest from the first axis, The first support portion and the second support portion are connected to the frame portion. A driving element characterized by the following features.

11. In the driving element according to any one of claims 1 to 10, The movable part has a reflective surface, A driving element characterized by the following features.

Images