ACTUATOR AND OPTICAL REFLECTING ELEMENT

Abstract

Provided is an actuator (100) comprising: a first drive body (110) which is provided with a first piezoelectric body (113) extending in a first axis direction crossing the polarization axis; a second drive body (120) which is provided with a second piezoelectric body (123) shorter than the first piezoelectric body (113) in the first axis direction; and a substrate (130) which holds the first drive body (110) and the second drive body (120) at base end portions in the first axis direction. The first drive body (110) and the second drive body (120) are connected to each other while arranged side by side in the polarization axis directions in a state in which the polarization axis of the first piezoelectric body (113) and the polarization axis of the second piezoelectric body (123) are substantially aligned to each other. The second piezoelectric body (123) is equal to or longer than the first piezoelectric body (113) in at least one of the length in the direction of a second axis orthogonal to the polarization axis and the first axis and the length in the polarization axis direction.

Description

[Technical field]

[0001] The present disclosure relates to an actuator including a piezoelectric body, and an optical reflecting element including the actuator. [Background technology]

[0002] An actuator equipped with a piezoelectric element generates a driving force by applying an electric field to the piezoelectric element, causing it to expand and contract. In an actuator with a unimorph structure, a plate that does not expand or contract in the direction of expansion and contraction of the piezoelectric element is bonded to one side of the piezoelectric element, and the expansion and contraction of the piezoelectric element relative to the plate is converted into warping of the plate. In an actuator with a bimorph structure, two piezoelectric elements are bonded so that their polarization directions are opposite to each other, and the expansion of one and the contraction of the other cause the entire actuator to warp.

[0003] The actuator described in Patent Document 1 is an actuator with a unimorph structure, and by adopting a cantilever structure with a fixed base end, the displacement of the tip end due to warping is utilized to change the angle of the mirror. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 114857 Summary of the Invention [Problem to be solved by the invention]

[0005] However, due to the nature of piezoelectric materials, in actuators equipped with piezoelectric materials, there is generally a trade-off between the amount of displacement and the force generated, making it difficult to realize an actuator with both a large amount of displacement and strong force generated.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide an actuator capable of achieving both a large amount of displacement and a strong generated force, and an optical reflecting element including such an actuator. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the present disclosure provides an actuator comprising a first driving body having a first piezoelectric body extending in a first axial direction intersecting a polarization axis, a second driving body having a second piezoelectric body shorter than the first piezoelectric body in the first axial direction, and a base body that holds the first driving body and the second driving body at their base ends in the first axial direction, wherein the first driving body and the second driving body are connected side by side in the polarization axis direction with the polarization axis of the first piezoelectric body and the polarization axis of the second piezoelectric body being roughly aligned, and the second piezoelectric body has at least one of the length in the polarization axis direction, the length in the second axial direction perpendicular to the first axis, and the length in the polarization axis direction that is the same as or longer than the first piezoelectric body. Effect of the Invention

[0008] According to the actuator of the present disclosure, a large amount of displacement and a large generated force can be obtained. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an actuator according to the first embodiment. [Diagram 2] FIG. 2 is a top view showing the actuator according to the first embodiment. [Diagram 3] FIG. 3 is a side view showing the actuator according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating the operation of the actuator according to the first embodiment. [Diagram 5] FIG. 5 is a side view showing the actuator according to the second embodiment. [Figure 6] FIG. 6 is a top view showing the actuator according to the second embodiment. [Figure 7] FIG. 7 is a side view showing the polarization treatment step in the second embodiment. [Figure 8] FIG. 8 is a side view showing expansion and contraction of the piezoelectric body when the actuator 1 is driven in the second embodiment. [Figure 9] FIG. 9 is a side view showing expansion and contraction of the piezoelectric body when the actuator 2 is driven in the second embodiment. [Figure 10] FIG. 10 is a graph showing the change over time of the voltage applied to the piezoelectric body when the actuator is driven in the second embodiment. [Figure 11] FIG. 11 is a perspective view showing an optical reflecting element in the third embodiment. [Figure 12] FIG. 12 is a side view showing another example of the actuator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of an actuator according to the present disclosure and an optical reflecting element using the actuator will be described with reference to the drawings. Note that the numerical values, shapes, materials, components, positional relationships of the components, connection states, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, although multiple inventions may be described as one embodiment below, components not described in the claims are described as optional components with respect to the invention according to the claims. In addition, the drawings are schematic diagrams in which emphasis, omission, and ratio adjustments have been made as appropriate to explain the present disclosure, and may differ from the actual shapes, positional relationships, and ratios.

[0011] (Embodiment 1) FIG. 1 is a perspective view showing an actuator in the first embodiment. FIG. 2 is a top view showing the actuator in the first embodiment. FIG. 3 is a side view showing the actuator in the first embodiment. The actuator 100 is a driving source of a cantilever structure in which a base end (the end on the Y- side in the figure) is held and a tip end (the end on the Y+ side in the figure) is displaced, and includes a first driving body 110, a second driving body 120, and a base body 130. In the case of the first embodiment, the actuator 100 includes a first conversion member 114 and a second conversion member 124.

[0012] The first driving body 110 is a member that expands and contracts in the distal direction relative to a fixed base end when an electric field is applied, and includes a first piezoelectric body 113 , a first electrode 111 , and a second electrode 112 .

[0013] The first piezoelectric body 113 is a so-called piezo element in which the polarization is aligned in the direction in which the first electrode 111 and the second electrode 112 are arranged (Z-axis direction in the figure). The shape of the first piezoelectric body 113 is not particularly limited, but in the case of the first embodiment, it is a rectangular parallelepiped shape. The rectangular parallelepiped shape includes a rectangular parallelepiped, and further includes a shape having a protrusion, a notch, a rounded portion, a tilt, or the like, as long as the shape looks like a rectangular parallelepiped as a whole. The first piezoelectric body 113 extends in a first axis direction (Y-axis direction in the figure) intersecting with the polarization axis (Z-axis in the figure), and the length in the first axis direction is set to L1, the length in the polarization axis direction is set to T1, and the length in the second axis direction (X-axis direction in the figure) perpendicular to the polarization axis and the first axis is set to W1. In addition, L1>T1 and L1>W1 are satisfied.

[0014] The first electrode 111 and the second electrode 112 are electrodes for applying an electric field to the first piezoelectric body 113. The first electrode 111 is disposed on one end face side in the polarization direction of the first piezoelectric body 113, and the second electrode 112 is disposed on the other end face side in the polarization direction of the first piezoelectric body 113. The first electrode 111 and the second electrode 112 are rectangular sheets having substantially the same shape as the maximum area surface of the first piezoelectric body 113. Substantially the same includes the same, and further includes a shape having a notch, a hole, a rounded portion, or the like, as long as the shape looks the same as the surface shape as a whole. Note that the part protruding from the first piezoelectric body 113 is not included in the first electrode 111 and the second electrode 112, even if it is integrated with the first electrode 111 or the second electrode 112, because it is not a part that applies an electric field to the first piezoelectric body 113.

[0015] The first conversion member 114 is a member that converts the expansion and contraction in the first axis direction of the first piezoelectric body 113 of the unimorph structure into bending in the polarization axis direction, and has flexibility that maintains a predetermined length in the first axis direction against the expansion and contraction of the first piezoelectric body 113, and allows bending in the polarization axis direction. The material of the first conversion member 114 is not particularly limited, and examples thereof include steel, silicon, and ceramics made of resin, oxide, and the like. In addition, when a conductor is used for the first conversion part 114, an insulating process may be performed, such as providing an insulating film on the conductor member in order to insulate it from the second electrode 112. In addition, the second electrode 112 may also have the function of the first conversion member 114.

[0016] The shape of first conversion member 114 is not particularly limited, but it is preferable that first conversion member 114 has a length in the first axial direction approximately equal to that of first piezoelectric body 113. In the case of the first embodiment, first conversion member 114 has a rectangular plate shape that is substantially the same as the shape of the surface of first piezoelectric body 113 with the largest area.

[0017] The second driving body 120 is a member that is shorter than the first driving body 110 in the first axial direction and expands and contracts in the tip direction relative to a fixed base end portion when an electric field is applied, and is equipped with a second piezoelectric body 123, a third electrode 121, and a fourth electrode 122.

[0018] The second piezoelectric body 123 is a so-called piezoelectric element in which the polarization is aligned in the direction in which the third electrode 121 and the fourth electrode 122 are arranged (Z-axis direction in the figure). The shape of the second piezoelectric body 123 is not particularly limited, but in the case of the first embodiment, it is a rectangular parallelepiped. The second piezoelectric body 123 extends in a first axis direction (Y-axis direction in the figure) intersecting with the polarization axis (Z-axis in the figure), and the length in the first axis direction is set to L2, the length in the polarization axis direction to T2, and the length in the second axis direction (X-axis direction in the figure) perpendicular to the polarization axis and the first axis to W2. In addition, L1>L2 is satisfied, and at least one of T1≦T2 and W1≦W2 is satisfied.

[0019] The first piezoelectric body 113 has a large displacement, and the second piezoelectric body 123 generates a large force, which are conditions for realizing the actuator 100 having a large displacement and a high generating force. This can be realized by simply making the shapes of the first piezoelectric body 113 and the second piezoelectric body 123 different from each other as described above, with the material constituting the first piezoelectric body 113 being substantially the same as the material constituting the second piezoelectric body 123. However, in this embodiment, in order to enhance the effect, the first piezoelectric body 113 and the second piezoelectric body 123 are made of different materials. Specifically, when an electric field of the same intensity is applied to the first piezoelectric body 113 and the second piezoelectric body 123 having the same shape and size, the material constituting the first piezoelectric body 113 has a larger displacement than the material constituting the second piezoelectric body 123, and the material constituting the second piezoelectric body 123 generates a larger generating force than the material constituting the first piezoelectric body 113. For example, it is possible to form the first piezoelectric body 113 from a soft material that is generally believed to provide a large displacement, and the second piezoelectric body 123 from a hard material that is generally believed to be capable of generating a high force. As a method for distinguishing between soft and hard materials, for example, materials with a mechanical quality factor of less than 300 may be classified as soft materials, and materials with a mechanical quality factor of 300 or more may be classified as hard materials.

[0020] The third electrode 121 and the fourth electrode 122 are electrodes for applying an electric field to the second piezoelectric body 123. The third electrode 121 is disposed on one end face side in the polarization direction of the second piezoelectric body 123, and the fourth electrode 122 is disposed on the other end face side in the polarization direction of the second piezoelectric body 123. The third electrode 121 and the fourth electrode 122 are in the form of a rectangular sheet having substantially the same shape as the surface of the second piezoelectric body 123 with the largest area.

[0021] The second conversion member 124 is similar to the first conversion member 114, and is a member that converts the expansion and contraction in the first axial direction of the second piezoelectric body 123 having a unimorph structure into bending in the polarization axis direction. It is possible for the third electrode 121 to also have the function of the second conversion member 124. The shape of the second conversion member 124 is not particularly limited, but it is preferable that the second conversion member 124 has a length in the first axial direction that is approximately the same as that of the second piezoelectric body 123. In the case of the first embodiment, the shape of the second conversion member 124 is a rectangular plate that is substantially the same as the shape of the surface of the second piezoelectric body 123 with the largest area.

[0022] The base 130 holds the first driving body 110 and the second driving body 120 at their base ends in the first axial direction. In the present embodiment, the base 130 is connected to the second driving body 120 in a surface contact state at the base end of the largest surface of the second driving body 120. The first driving body 110 is disposed such that its base end overlaps with the base 130 in the first axial direction, and is held by the base 130 via the second driving body 120.

[0023] The shape and structure of the base 130 are not particularly limited. In the case of the present embodiment 1, the base 130 is a rectangular parallelepiped extending in the second axis direction (X-axis direction in the figure), and in the second axis direction, the length of the base 130 is longer than the first driving body 110 and the second driving body 120. In the first axis direction, the base 130 is arranged so as to protrude from the base end face of the first driving body 110 and the base end face of the second driving body 120. Since the role of the base part is to hold the first driving body and the second driving body, in addition to the arrangement shown in the present embodiment 1, a case in which the driving body and the base are connected at the end faces on the negative side (Y-side) of the first axis of the first driving body and the second driving body can also be considered.

[0024] The first driver 110 and the second driver 120 are connected side by side in the polarization axis direction (Z-axis direction in the figure) with the polarization axis of the first piezoelectric body 113 and the polarization axis of the second piezoelectric body 123 roughly aligned. The base end surface of the first driver 110 and the base end surface of the second driver 120 are substantially aligned in the first axial direction. Substantially aligned includes cases where they are completely aligned and cases where they are misaligned to expose the electrodes. The base end of the maximum area surface of the first driver 110 in the first axial direction and the central portion of the maximum area surface of the second driver 120 are connected in a surface contact state.

[0025] The method of forming the actuator 100 is not particularly limited. In addition, the method of formation varies depending on the size and use of the actuator 100, and the desired actuator performance. For example, the actuator 100 may be formed by manufacturing each component separately and then bonding these components. The actuator 100 may also be formed using a technique for manufacturing MEMS (Micro Electro Mechanical Systems). The first conversion member 114 and the second conversion member 124 may be shared, and this configuration allows the actuator 100 to be manufactured more easily.

[0026] 4 is a diagram showing the operation of the actuator. When an electric field is applied so that the first piezoelectric body 113 shrinks relative to the first conversion member 114 in the first axial direction (Y-axis direction in the figure) as shown in row a in FIG. 4, the first driving body 110 warps, and the tip of the first driving body 110 is displaced in the direction away from the base 130 in the polarization axis direction (Z+ direction in the figure). When an electric field is applied so that the second piezoelectric body 123 expands relative to the second conversion member 124 in the first axial direction (Y-axis direction in the figure), the second driving body 120 warps in the same direction as the first driving body 110, and the tip of the second driving body 120 is displaced in the direction away from the base 130 in the polarization axis direction (Z+ direction in the figure).

[0027] By the above operation, the first driving body 110, which is relatively long in the first axis direction, can realize a large displacement amount at the tip. In addition, the second driving body 120, which is relatively short in the first axis direction and long in the polarization axis direction (thickness direction) and the second axis direction (width direction), generates a force larger than that of the first driving body 110, and this force is added to the generated force of the first driving body, generating a force that cannot be generated by the first driving body 110 alone. Furthermore, by shortening only the second driving body 120, an actuator 100 with a large generated force can be realized without reducing the tip displacement amount, compared to when the length of the second driving body 120 is the same as that of the first driving body 110. Furthermore, by shortening only the second driving body 120, the mass of the tip can be reduced and the natural vibration frequency of the actuator 100 can be increased, compared to when the length of the second driving body 120 is the same as that of the first driving body 110.

[0028] 4, when an electric field opposite to the above is applied so that the first piezoelectric body 113 expands relative to the first conversion member 114 in the first axial direction, the first driving body 110 warps, and the tip of the first driving body 110 is displaced in the direction approaching the base 130 in the polarization axis direction (Z-direction in the figure). When an electric field opposite to the above is applied so that the second piezoelectric body 123 contracts relative to the second conversion member 124 in the first axial direction, the second driving body 120 warps in the same direction as the first driving body 110, and the tip of the second driving body 120 is displaced in the direction approaching the base 130 in the polarization axis direction (Z-direction in the figure).

[0029] By the above operation, the tip of the first driving body 110 can generate a large amount of displacement and a force that cannot be generated by the first driving body 110 alone. Furthermore, compared to the case where the length of the second driving body 120 is the same as the length of the first driving body 110, by shortening only the second driving body 120, the actuator 100 can be realized with a large amount of tip displacement without a significant decrease in the generated force. Furthermore, compared to the case where the length of the second driving body 120 is the same as the length of the first driving body 110, by shortening only the second driving body 120, the mass of the tip can be reduced and the natural vibration frequency of the actuator 100 can be increased. In addition, by applying an AC electric field to each of the first driving body 110 and the second driving body 120, the state shown in row a and the state shown in row b in FIG. 4 can be alternately repeated. As a result, the tip of the first driving body 110 of the actuator 100 can be vibrated with a large stroke and a large generated force.

[0030] (Embodiment 2) Another embodiment of the actuator 100 will be described. Note that parts having the same actions, functions, shapes, mechanisms, and structures as those in the first embodiment will be given the same reference numerals and the description thereof may be omitted. Also, the following description will be centered on the points that are different from the first embodiment, and the description of the same contents may be omitted.

[0031] Fig. 5 is a side view showing the actuator in embodiment 2. Fig. 6 is a top view showing the actuator in embodiment 2. Arrows shown inside first piezoelectric body 113 and second piezoelectric body 123 in Fig. 5 indicate the polarization direction.

[0032] The first piezoelectric body 113 is divided into two layers in the polarization direction at least at the tip, and one layer has a reverse polarization layer 115 whose polarization direction is opposite to that of the other layer. In other words, the tip of the first piezoelectric body 113 has a bimorph structure by itself, and the base end has a bimorph structure by being laminated with the second piezoelectric body 123. In the case of the second embodiment, the entire first piezoelectric body 113 is divided into two layers in the polarization axis direction, and the reverse polarization layer 115 spreads from the tip to a position corresponding to the tip surface of the second piezoelectric body 123. An intermediate electrode 116 is disposed between the two layers of the first piezoelectric body 113. In addition, the first driving body 110 has a tip electrode 117 for applying an electric field only to the tip of the first driving body 110 on the surface at a position corresponding to the reverse polarization layer 115. A stepwise polarization process is performed for local polarization in the first piezoelectric body 113. 7 is a side view showing a polarization process of the first piezoelectric body 113 in the second embodiment. First, an electric field is applied between the second electrode 112 and the intermediate electrode 116 to align the polarization direction of the piezoelectric layer between these electrodes (stage a in FIG. 7). Next, an electric field is applied between the first electrode 111 and the intermediate electrode 117 so that the polarization direction of the piezoelectric body between the first electrode 111 and the intermediate electrode 117 is the same as the polarization direction of the piezoelectric body between the second electrode 112 and the intermediate electrode 116 (stage b in FIG. 7). Then, in order to form the reverse polarization layer 115 at the tip of the first piezoelectric body 113, an electric field is applied between the intermediate electrode 116 and the tip electrode 117 so that the polarization direction is the opposite direction to the polarization direction of the piezoelectric body between the second electrode 112 and the intermediate electrode 116 (stage c in FIG. 7).

[0033] FIG. 8 is a side view showing the expansion and contraction of the piezoelectric body when the actuator is driven 1 in the second embodiment. FIG. 9 is a side view showing the expansion and contraction of the piezoelectric body when the actuator is driven 2 in the second embodiment. Here, the arrows in the first piezoelectric body 113 and the second piezoelectric body 123 in FIG. 8 and FIG. 9 indicate the direction of expansion and contraction of the piezoelectric body. The second electrode 112 of the first driving body 110 and the third electrode 121 of the second driving body in contact therewith are set to ground potential, and as shown in FIG. 10, electric fields of the same phase are applied by the power sources 142 and 143, and an electric field of the opposite phase, which is inverted by 180 degrees, is applied by the power source 141. By applying an alternating current from the power sources 141, 142, and 143 using this electric field application method, the actuator 100 repeats amplitude in the Z+ and Z- directions.

[0034] The actuator 100 of the second embodiment does not require a conversion member and can be easily manufactured. Also, a part of the second electrode 112 of the first driving body 110 may be the third electrode 121 of the second driving body, and with this configuration, the actuator 100 can be manufactured even more easily.

[0035] (Embodiment 3) Next, an embodiment of the optical reflecting element 200 will be described. Note that parts having the same actions, functions, shapes, mechanisms, and structures as those in the first and second embodiments will be given the same reference numerals and descriptions thereof may be omitted. Also, the following description will be centered on the points that are different from the first and second embodiments, and descriptions of the same contents may be omitted.

[0036] 11 is a perspective view showing an optical reflecting element in embodiment 3. Optical reflecting element 200 is an element used in, for example, a projector that periodically changes the reflection angle of laser light to sweep the irradiation position of light to project an image or the like, and includes a plurality of actuators 100 and a reflector 210.

[0037] Actuator 100 included in optical reflecting element 200 is not particularly limited as long as it is related to the present disclosure. In embodiment 3, two actuators 100 having the structure exemplified in embodiment 1 are adopted. In optical reflecting element 200, two actuators 100 are arranged so that the first axis direction (Y axis direction in the figure) and the polarization axis direction (Z axis direction in the figure) are parallel to each other. In addition, the base end faces of first piezoelectric bodies 113 are arranged in the same plane, and the base end faces of second piezoelectric bodies 123 are arranged in the same plane.

[0038] The base ends of first piezoelectric bodies 113 of the two actuators 100 are integrally connected by first connecting part 221. This makes it possible to stabilize the relative positional accuracy of the tip ends of the two first driving bodies 110, and allows reflector 210 to be attached with high positional accuracy. Therefore, it becomes possible to stably manufacture high-precision optical reflecting element 200.

[0039] In the case of the third embodiment, the base ends of the second piezoelectric bodies 123 are also integrally connected to each other by the second connecting portion 222. Moreover, the base body 130 has a length sufficient to commonly hold the two first driving bodies 110 and the two second driving bodies 120. This makes it possible to improve the attachment accuracy of the two first driving bodies 110 integrated together by the first connecting portion 221 and the two second driving bodies 120 integrated together by the second connecting portion 222.

[0040] The reflector 210 is a member that is connected in a bridge-like manner between the tips of the first driving bodies 110 of the multiple actuators 100. The reflector 210 is a member that rotates and oscillates (repeatedly rotates and oscillates) around a first axis at the center between the tips of the two first driving bodies 110, and reflects light. The shape of the reflector 210 is not particularly limited, but in this embodiment, it is a circular plate, and has a mirror (not shown) on its surface that can reflect the light to be reflected with high reflectance. The material of the mirror can be selected arbitrarily, and examples of the material include metals such as gold, silver, and aluminum, and metal compounds. The mirror may be provided by polishing the surface of the reflector 210 until it is smooth. The mirror may be not only flat but also curved.

[0041] The reflector 210 includes a rotation shaft portion 211 for connecting to the tip portions of the two first driving bodies 110 in a bridging manner, a beam portion 212, and a joint portion 213.

[0042] The rotating shaft portion 211 is a rod-shaped member disposed along the first axis, one end of which is connected to the reflector 210, and the other end of which is connected to the beam portion 212. The rotating shaft portion 211 is a member that transmits torque to the reflector 210 for rotating and swinging the reflector 210, and is configured to rotate and swing the reflector 210 while holding it by twisting the rotating shaft portion 211 around the first axis. In the case of the third embodiment, the rotating shaft portion 211 is separated into two in the second axial direction (X-axis direction in the figure), which reduces the concentration of stress when twisting.

[0043] Beam portion 212 is a portion that bridges rotating shaft portion 211 and joint portion 213 attached to the tip of actuator 100. In the case of embodiment 3, beam portion 212 is disposed so as to protrude from both ends of rotating shaft portion 211 that is separated into two pieces toward joint portion 213.

[0044] The joints 213 are portions that are joined to the tip ends of the first driving bodies 110 of the actuators 100. The joints 213 are rectangular plate-shaped, and are in contact with the first driving bodies 110 over a wide area, ensuring a strong joining force.

[0045] In the above optical reflecting element 200, reflector 210 can be rotationally vibrated around the first axial direction as the center of rotation by vibrating the tips of two actuators 100 in opposite phases. Furthermore, optical reflecting element 200 rotates reflector 210 by actuators 100 whose tips have large amplitude and generate strong force, so the range (rotation angle) of rotational vibration of reflector 210 can be widened.

[0046] The present disclosure is not limited to the above-mentioned embodiment. For example, the present disclosure may be realized by combining the components described in this specification in any way, or by excluding some of the components. In addition, the present disclosure also includes modifications obtained by applying various modifications that a person skilled in the art can think of to the above-mentioned embodiment without departing from the gist of the present disclosure, that is, the meaning of the words described in the claims.

[0047] For example, in embodiment 1, the length T in the polarization axis direction and the length W in the second axis direction are longer in second piezoelectric body 123 than in first piezoelectric body 113, but it is acceptable for only one of them to be the same or longer.

[0048] Furthermore, as shown in FIG. 12, the second driving body 120 may be disposed at a position farther away from the base body 130 than the first driving body 110. In this case, as shown in FIG.

[0049] In the second embodiment, the second piezoelectric body 123 may have a bimorph structure. [Industrial Applicability]

[0050] The present disclosure can be used in devices that are operated by small actuators, projectors that display images by reflecting laser light, and the like. [Explanation of symbols]

[0051] 100 Actuator 110 First Drive Body 111 First electrode 112 Second electrode 113 First Piezoelectric Body 114 First conversion member 115 Reverse Polarization Layer 116 Intermediate electrode 117 Tip electrode 120 Second driver 121 Third electrode 122 Fourth electrode 123 Second Piezoelectric Body 124 Second conversion member 130 Base 141 Power supply 1 142 Power supply 2 143 Power supply 3 200 Optical Reflection Element 210 Reflector 211 Rotating shaft 212 Beam section 213 Joint 221 First connection part 222 Second connection part

Claims

1. A first driver including a first piezoelectric element extending in a first axis direction intersecting the polarization axis; a second driving body including a second piezoelectric body that is shorter than the first piezoelectric body in the first axial direction; a base body that holds the first driving body and the second driving body at base ends in the first axial direction; the first driving body and the second driving body are connected in a line in a polarization axis direction with a polarization axis of the first piezoelectric body and a polarization axis of the second piezoelectric body being substantially aligned; The second piezoelectric element is longer than the first piezoelectric element in at least one of the length in the direction of the polarization axis, the length in the direction of a second axis perpendicular to the first axis, and the length in the direction of the polarization axis. Actuator.

2. A first driving body having a first piezoelectric body extending in a first axial direction intersecting a polarization axis; a second driving body including a second piezoelectric body that is shorter than the first piezoelectric body in the first axial direction; a base body that holds the first driving body and the second driving body at base ends in the first axial direction; the first driving body and the second driving body are connected in a line in a polarization axis direction with a polarization axis of the first piezoelectric body and a polarization axis of the second piezoelectric body being substantially aligned; the second piezoelectric body is equal to or longer than the first piezoelectric body in at least one of the length in the direction of the polarization axis, the length in the direction of a second axis perpendicular to the first axis, and the length in the direction of the polarization axis; When an electric field of the same strength is applied to the first piezoelectric body and the second piezoelectric body having the same shape and size, the material constituting the first piezoelectric body is displaced more than the material constituting the second piezoelectric body, and the material constituting the second piezoelectric body generates a stronger force than the material constituting the first piezoelectric body. Actuator.

3. The first piezoelectric body is A part or the whole of the substrate is divided into two layers in the polarization axis direction, and at least one of the two layers has an opposite polarization layer having a polarization direction opposite to that of the other layer.

3. The actuator according to claim 1 or 2.

4. The first driving body includes the first piezoelectric body, and a first electrode and a second electrode provided on either side of the first piezoelectric body to apply an electric field in the polarization axis direction of the first piezoelectric body, and at least one of the electrodes is electrically separated into two or more. The actuator according to claim 3.

5. A plurality of actuators according to any one of claims 1 to 4; A reflector connected in a bridging manner between respective tips of the first driving bodies of the plurality of actuators; An optical reflective element comprising:

6. A first connecting portion is provided to integrally connect base ends of the first piezoelectric bodies provided in each of the plurality of actuators.

6. The optical reflecting element according to claim 5.

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