TWI857576B - Piezoelectric actuating apparatus - Google Patents

Abstract

A piezoelectric actuating apparatus including a frame body, a rotating part, a first actuating element, a second actuating element, a sensing element, a plurality of transmission elements, a sensing electrode and a driving electrode is provided. The frame body has an opening. The rotating part is located in the opening and connected to the frame body via a rotating shaft structure. The rotating part is configured to reciprocatingly swing relative to the frame body with an axis of the rotating shaft structure as the center. The first actuating element is connected to the rotating part. The transmission elements are disposed between the first actuating element and the second actuating element, and between the first actuating element and the sensing element. The second actuating element and the sensing element are coupled to the rotating part via the transmission elements. The sensing electrode is disposed on a part of the transmission elements and the sensing element. The driving electrode is disposed on the other part of the transmission elements, the first actuating element and the sensing element.

Description

Piezoelectric actuator

The present invention relates to an actuating device, and in particular to a piezoelectric actuating device.

Reflective micro mirrors can be used in optical projection, optical communication, and optical ranging radar applications. Compared with micro mirrors manufactured by precision machining and micro mirror components designed by combining micro-electromechanical systems (MEMS) with semiconductor process integration manufacturing technology, reflective micro mirrors can achieve advantages such as mass production, cost savings, miniaturization, and electronic circuit integration. The driving methods of micro mirrors can be mainly divided into three types: electrostatic drive, electromagnetic drive, and piezoelectric drive.

The electrostatic drive method uses multiple sets of parallel staggered capacitors to drive the micro-mirror by utilizing the electrostatic force generated by the fringe effect of the electric field on the parallel capacitors. However, due to electrostatic considerations, the distance between the comb actuators used in the electrostatic drive micro-mirror cannot be too far, which leads to the risk of electrode short circuit and increased process difficulty.

The electromagnetic drive method is to lay electromagnetic coils on the micro-mirror and set magnetic materials outside the micro-mirror. However, dense coils with high current will have problems with poor heat dissipation and power consumption, affecting component reliability. The magnetic material that provides the magnetic field is difficult to integrate using semiconductor processes, and the magnetic material and micro-mirror need to be integrated using an assembly method, which greatly increases the system size.

The piezoelectric drive method is based on the characteristics of piezoelectric materials. When an external voltage is applied to the piezoelectric material, the piezoelectric material generates a strain force, which then drives the micro-mirror to rotate. The current piezoelectric micro-mirror actuators are mostly designed with a folding cantilever beam design to increase the deformation of the actuator. However, the folding cantilever beam design takes up a large area and also has the problem of insufficient rigidity of the micro-mirror.

The "prior art" section is only used to help understand the content of the present invention. Therefore, the content disclosed in the "prior art" section may contain some content that does not constitute the common knowledge of the person skilled in the art. The content disclosed in the "prior art" section does not mean that the content or the problem to be solved by one or more embodiments of the present invention has been known or recognized by the person skilled in the art before the application of the present invention.

The present invention provides a piezoelectric actuator which can achieve high control accuracy, large scanning angle and high scanning frequency under the design of small component size.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

To achieve one or part or all of the above purposes or other purposes, an embodiment of the present invention provides a piezoelectric actuation device, which includes a frame, a rotating member, a first actuation element, a second actuation element, a sensing element, a plurality of transmission elements, a sensing electrode and a driving electrode. The frame has an opening. The rotating member is located in the opening and is connected to the frame via a rotating shaft structure. The rotating shaft structure has an axis. The rotating member is suitable for reciprocating relative to the frame with the axis as the center. The first actuation element is arranged between the frame and the rotating member, and the first actuation element is connected to the rotating member. The second actuation element is arranged between the frame and the rotating member, and the second actuation element is connected to the frame. The sensing element is arranged between the frame and the rotating member, and the sensing element is connected to the frame. The sensing element and the second actuating element are symmetrically arranged on opposite sides of the axis of the rotating shaft structure with the axis of the rotating shaft structure as the center. The transmission element is arranged between the first actuating element and the second actuating element and between the first actuating element and the sensing element, and the second actuating element and the sensing element are coupled to the rotating member through the transmission element. The sensing electrode is arranged on a part of the transmission element and the sensing element. The driving electrode is arranged on another part of the transmission element, the first actuating element and the second actuating element.

In one embodiment of the present invention, the first actuating element, the second actuating element, the sensing element and the transmission element comprise piezoelectric materials.

In one embodiment of the present invention, the driving electrode is used to receive a driving signal to cause the second actuating element, the first actuating element and the transmission element to deform, thereby driving the rotating element to rotate. The sensing electrode is used to receive a sensing voltage generated by the corresponding deformation of the sensing element driven by the rotation of the rotating element, and output a sensing signal.

In one embodiment of the present invention, the first actuating element comprises a plurality of first sub-actuating elements. The first sub-actuating elements are symmetrically arranged beside the rotating shaft structure with the axis of the rotating shaft structure as the center.

In one embodiment of the present invention, the first sub-actuating element is triangular in shape.

In one embodiment of the present invention, the second actuating element is U-shaped or C-shaped.

In one embodiment of the present invention, the transmission element is symmetrically arranged on two opposite sides of the axis with the axis of the rotating shaft structure as the center.

In one embodiment of the present invention, the first actuating element comprises a plurality of first sub-actuating elements. The transmission elements are respectively S-shaped or bent. The transmission element is connected between one of the first sub-actuating elements and one of the second actuating element and the sensing element.

In one embodiment of the present invention, the first actuating element comprises a plurality of first sub-actuating elements. The driving electrode comprises five sub-actuating electrodes. The sub-actuating electrodes are respectively arranged on one of the first sub-actuating element and the second actuating element. The sub-actuating electrode arranged on the second actuating element is extended and arranged on a transmission element adjacent to the second actuating element.

In one embodiment of the present invention, when the above-mentioned driving electrodes receive driving signals to cause the first actuator element and the second actuator element to drive the rotating member to rotate, among the sub-driving electrodes arranged on the first sub-actuating element, the driving signals received by the sub-driving electrodes located on the same side of the axis of the rotating shaft structure have the same phase, and the driving signals received by the sub-driving electrodes located on different sides of the axis have opposite phases.

In one embodiment of the present invention, the driving signal received by the sub-driving electrode disposed on the second actuating element has an opposite phase to the driving signal received by the sub-driving electrode disposed on the first sub-driving element adjacent to the second actuating element.

In one embodiment of the present invention, the piezoelectric actuator further includes an elastic element. The elastic element is disposed between the frame and the first actuator along the axis of the rotating shaft structure.

In one embodiment of the present invention, the rotating member has two slots, and the axis of the rotating shaft structure passes through the two slots.

In one embodiment of the present invention, a blank area is provided at the connection between the transmission element and the first actuating element, and the blank area is a region where no piezoelectric material is provided.

In one embodiment of the present invention, the piezoelectric actuator further includes a reflective layer disposed on the first surface of the rotating element.

In one embodiment of the present invention, the piezoelectric actuator further includes a reinforcing structure disposed on a second surface of the rotating member opposite to the first surface.

In one embodiment of the present invention, the reinforcement structure is ring-shaped.

Based on the above, in the piezoelectric actuator of an embodiment of the present invention, since the second actuator element and the sensing element are coupled to the rotating element through the transmission element, and the piezoelectric actuator is designed as the first actuator element, the second actuator element, the transmission element and the sensing element are symmetrically arranged in the frame with the rotating element as the center. Therefore, the piezoelectric actuator can achieve the effects of high control accuracy, large scanning angle and high scanning frequency under the design of small element size. Moreover, since piezoelectric material is used as the material of the actuator element, the piezoelectric actuator is also easy to meet the requirements of easy mass production.

The above-mentioned other technical contents, features and effects of the present invention will be clearly presented in the detailed description of the preferred embodiment with reference to the following drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only referenced to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and are not used to limit the present invention.

FIG. 1 is a schematic top view of a piezoelectric actuator according to an embodiment of the present invention. FIG. 2 is a schematic three-dimensional view of a piezoelectric actuator according to an embodiment of the present invention. Referring to FIG. 1 and FIG. 2 , an embodiment of the present invention provides a piezoelectric actuator 10, which includes a frame 100, a rotating member 200, a first actuator element 300, a second actuator element 400, a sensing element 500, a plurality of transmission elements 600, a sensing electrode 700, and a driving electrode 800.

In this embodiment, the frame 100 has an opening O. The rotating member 200 is located in the opening O and connected to the frame 100 via a rotating shaft structure RS. The rotating shaft structure RS has an axis RA. The rotating member 200 is suitable for reciprocating relative to the frame 100 with the axis RA as the center (as shown in FIG. 11 ).

In this embodiment, the first actuator 300 is disposed between the frame 100 and the rotating member 200, and the first actuator 300 is connected to the rotating member 200. The second actuator 400 is disposed between the frame 100 and the rotating member 200, and the second actuator 400 is connected to the frame 100. The sensing element 500 is disposed between the frame 100 and the rotating member 200, and the sensing element 500 is connected to the frame 100. The first actuator 300, the second actuator 400, and the sensing element 500 surround the rotating member 200. The second actuator 400 and the sensing element 500 extend from the side of the frame 100 to the opening O of the frame 100. In this embodiment, on a reference plane parallel to the rotating member 200 when not rotating, the second actuator 400 and the sensing element 500 are, for example, U-shaped or C-shaped. More specifically, the contours of the second actuator 400 and the sensing element 500 are flat-concave, and the contours of the second actuator 400 and the sensing element 500 are straight lines toward the side of the frame 100 and are inwardly concave curves toward the side of the rotating member 200. In this embodiment, the second actuator 400 and the sensing element 500 are symmetrically arranged on opposite sides of the axis RA of the rotating shaft structure RS with the axis RA as the center, so that the piezoelectric actuator device 10 can be more stable during operation.

In this embodiment, the transmission element 600 is disposed between the first actuating element 300 and the second actuating element 400 and between the first actuating element 300 and the sensing element 500, and the second actuating element 400 and the sensing element 500 are coupled to the rotating member 200 via the transmission element 600. The sensing electrode 700 is disposed on a portion of the transmission element 600 and the sensing element 500. The driving electrode 800 is disposed on another portion of the transmission element 600, the first actuating element 300, and the second actuating element 400.

In this embodiment, the first actuator element 300, the second actuator element 400, the sensing element 500 and the transmission element 600 include piezoelectric materials. The driving electrode 800 is used to receive a driving signal to cause the second actuator element 400, the first actuator element 300 and the transmission element 600 to deform, so as to drive the rotating member 200 to rotate. More specifically, when the first actuator element 300 and the second actuator element 400 are enabled and have a positive voltage, the piezoelectric material will generate a compressive strain and drive the first actuator element 300 and the second actuator element 400 to generate a contraction deformation, bend upward relative to the frame 100, and drive the rotating member 200 to rotate along a direction with the axis RA of the rotating shaft structure RS as the central axis. In contrast, when the first actuator 300 and the second actuator 400 are enabled and have a negative voltage, the piezoelectric material generates tensile strain, driving the first actuator 300 and the second actuator 400 to generate tensile deformation, bending downward relative to the frame 100, and driving the rotating member 200 to rotate in a direction opposite to the above direction with the axis RA of the rotating shaft structure RS as the center axis.

The sensing electrode 700 is used to receive the sensing voltage generated by the corresponding deformation of the sensing element 500 caused by the rotation of the rotating member 200, and output a sensing signal. More specifically, when the driving electrodes 800 on the first actuating element 300 and the second actuating element 400 are applied with a positive voltage to drive the rotating member 200 to rotate, the sensing electrode 700 will have a negative voltage because the sensing element 500 is applied with a deformation in the opposite direction to the first actuating element 300 and the second actuating element 400, thereby generating a corresponding sensing signal.

In this embodiment, the first actuator 300 includes a plurality of first sub-actuating elements 302, 304, 306, 308. The first sub-actuating elements 302, 304, 306, 308 are symmetrically arranged beside the rotating shaft structure RS with the axis RA of the rotating shaft structure RS as the center. In the reference plane parallel to the rotating member 200 when not rotating, the first sub-actuating elements 302, 304, 306, 308 are triangular.

In this embodiment, the transmission element 600 is used to transmit the actuation force from the second actuation element 400 to the first actuation element 300, and the transmission element 600 also has the function of releasing stress. The transmission element 600 is an elastic body, and on a reference plane parallel to the rotating member 200 when not rotating, the transmission element 600 is, for example, S-shaped or bent. The bend on the S-shaped or bent shape of the transmission element 600 can convert part of the stress into structural deformation to release the stress at the bend on the transmission element 600, which helps to reduce the risk of damage to the piezoelectric actuator 10.

In this embodiment, the number of the plurality of transmission elements 600 is embodied as 4, including a first transmission element 602, a second transmission element 604, a third transmission element 606, and a fourth transmission element 608. The transmission elements 600 are symmetrically arranged on opposite sides of the axis RA with the axis RA of the rotating shaft structure RS as the center. The transmission elements 600 are connected between one of the first sub-actuating elements 302, 304, 306, 308 and one of the second actuator element 400 and the sensing element 500. For example, the first transmission element 602 and the second transmission element 604 are respectively connected between the first sub-actuating element 302, 304 and the sensing element 500. After the vibration energy of the rotating element 200 is first transmitted to the first sub-actuating element 302, 304, the first transmission element 602 and the second transmission element 604 are used to transmit the vibration energy of the rotating element 200 from the first sub-actuating element 302, 304 to the sensing element 500. The third transmission element 606 and the fourth transmission element 608 are respectively connected between the first sub-actuating element 306, 308 and the second actuator 400. The third transmission element 606 and the fourth transmission element 608 are used to transmit the actuating force from the second actuator 400 to the first sub-actuating element 306, 308 to drive the rotating element 200 to rotate.

In this embodiment, the sensing electrode 700 is disposed on the sensing element 500 , and is extended to be disposed on the transmission elements 600 (ie, the first transmission element 602 and the second transmission element 604 ) adjacent to the sensing element 500 .

In this embodiment, the driving electrode 800 includes five sub-driving electrodes 802, 804, 806, 808, and 810. The sub-driving electrodes 802, 804, 806, 808, and 810 are respectively disposed on one of the first sub-actuating elements 302, 304, 306, and 308 and the second actuating element 400. For example, the sub-driving electrodes 802, 804, 806, and 808 are respectively disposed on the first sub-actuating elements 302, 304, 306, and 308, and the sub-driving electrode 810 is disposed on the second actuating element 400. The sub-driving electrode 810 disposed on the second actuating element 400 is extended and disposed on the transmission element 600 (i.e., the third transmission element 606 and the fourth transmission element 608) adjacent to the second actuating element 400. In addition, the sub-driving electrodes 802 and 806 are not connected, and the sub-driving electrodes 804 and 808 are not connected.

In this embodiment, when the driving electrode 800 receives the driving signal to cause the first actuator element 300 and the second actuator element 400 to drive the rotating member 200 to rotate, among the sub-driving electrodes 802, 804, 806, 808 arranged on the first sub-actuating element 302, 304, 306, 308, the driving signals received by the sub-driving electrodes located on the same side of the axis RA of the rotating shaft structure RS have the same phase, and the driving signals received by the sub-driving electrodes located on different sides of the axis RA have opposite phases. In addition, the driving signal received by the sub-driving electrode 810 disposed on the second actuator element 400 has an opposite phase to the driving signal received by the sub-driving electrodes 806, 808 disposed on the first sub-driving elements 306, 308 adjacent to the second actuator element 400. In other words, the driving signals received by the sub-driving electrodes 802, 804, 810 have a phase, and the driving signals received by the sub-driving electrodes 806, 808 have a phase, but the driving signals received by the sub-driving electrodes 802, 804, 810 have an opposite phase to the driving signals received by the sub-driving electrodes 806, 808.

In this embodiment, the first actuator 300 is used to generate a torque actuating force, and the second actuator 400 is used to generate a linear actuating force. After the sub-driving electrodes 802, 804, 806, 808, 810 receive the driving signal, the second actuator 400 is driven to generate an actuating force perpendicular to a reference plane parallel to the rotating member 200 when it is not rotated, and the first actuator 300 is used as a lever arm to generate torque to drive the rotating member 200 to rotate. Among them, in addition to serving as a lever arm of the second actuator 400, the first actuator 300 itself will also be driven to generate torque. In other words, the first actuator 300 has the functions of serving as a lever arm and generating torque at the same time, which can achieve the effect of effectively using the component area. In this embodiment, the first actuator 300 itself can generate torque, and further generate a larger torque by transmitting the actuation force from the second actuator 400 through the transmission element 600. Therefore, the piezoelectric actuator device 10 can achieve the effect of having a large scanning angle by integrating the first actuator 300 and the second actuator 400.

FIG3 is a schematic cross-sectional view along the section line A-A' in FIG1 or FIG2. In FIG1 or FIG2, the section line A-A' and the axis line RA are parallel to each other but do not overlap. Referring to FIG1, FIG2 and FIG3, in this embodiment, the first sub-actuating element 302 includes an actuating body 302-1, a piezoelectric material 302-2 and a lower electrode 302-3. The first sub-actuating element 304 includes an actuating body 304-1, a piezoelectric material 304-2 and a lower electrode 304-3.

In the present embodiment, the piezoelectric actuator 10 further includes a reflective layer 1000 disposed on the first surface 200S1 of the rotating member 200. The reflective layer 1000 is, for example, a metal reflective layer or a reflective mirror. The rotating member 200 has two slots ST, and the two slots ST surround the reflective layer 1000. The slots ST are, for example, through holes penetrating the rotating member 200 or grooves recessed relative to the surface of the rotating member 200. The axis RA of the rotating shaft structure RS passes through the two slots ST, thereby releasing the torsional stress generated at the connection between the rotating shaft structure RS and the frame 100 due to the reciprocating rotation of the rotating member 200.

In this embodiment, the piezoelectric actuator 10 further includes elastic elements 902 and 904. The elastic elements 902 and 904 are disposed between the frame 100 and the first actuator 300 along the axis RA of the rotating shaft structure RS. The elastic elements 902 and 904 are respectively located on opposite sides of the rotating member 200, the first sub-actuating elements 302 and 306 are connected to the frame 100 via the elastic element 902, and the first sub-actuating elements 304 and 308 are connected to the frame 100 via the elastic element 904. The elastic elements 902 and 904 are, for example, springs and are used to limit the deformation of at least one of the first actuating element 300, the second actuating element 400, the sensing element 500 and the transmission element 600 to prevent the piezoelectric actuating device 10 from being damaged due to excessive deformation or actuating force.

FIG4 is a schematic cross-sectional view along the section line B-B' in FIG1 or FIG2. Referring to FIG1, FIG2 and FIG4, in this embodiment, the first sub-actuating element 306 includes an actuating body 306-1, a piezoelectric material 306-2 and a lower electrode 306-3. The actuating body 306-1 is connected to the actuating body 302-1, the piezoelectric material 306-2 is connected to the piezoelectric material 302-2, and the lower electrode 306-3 is connected to the lower electrode 302-3.

FIG5 is an enlarged three-dimensional schematic diagram of the region R1 in FIG1. FIG6 is a cross-sectional schematic diagram along the section line C-C' in FIG5. Referring to FIG5 and FIG6, in this embodiment, the sensing element 500 includes a sensing body 500-1, a piezoelectric material 500-2, and a lower electrode 500-3. The transmission element 600 includes a transmission body, a piezoelectric material, and a lower electrode. For example, the first transmission element 602 includes a transmission body 602-1, a piezoelectric material 602-2, and a lower electrode 602-3, wherein the lower electrode 602-3 is disposed between the transmission body 602-1 and the piezoelectric material 602-2. In addition, a driving electrode 800 and a sensing electrode 700 may be disposed on the piezoelectric material of the transmission element 600. For example, as shown in FIG5 and FIG6, a sub-driving electrode 802 and a sensing electrode 700 are disposed on the piezoelectric material 602-2 of the first transmission element 602. The sub-driving electrode 802 disposed on the first sub-actuating element 302 and the sensing electrode 700 disposed on the sensing element 500 are extended and disposed on the first transmission element 602. In addition, the sub-driving electrode 802 and the sensing electrode 700 are disposed alternately along a direction parallel to the axis RA.

FIG7 is an enlarged three-dimensional schematic diagram of the region R2 in FIG1. FIG8 is a cross-sectional schematic diagram along the section line D-D' in FIG7. Referring to FIG7 and FIG8, in this embodiment, the second transmission element 604 includes a transmission body 604-1, a piezoelectric material 604-2, and a lower electrode 604-3. In addition, a blank area ER is provided at the connection between the transmission element 600 and the first actuator element 300, and the blank area ER is a region where the driving electrode 800 and the piezoelectric material are not provided. For example, in FIG5 , a blank area ER is provided at the connection between the first transmission element 602 and the first sub-actuating element 302. The blank area ER only has the transmission body 602-1 and the lower electrode 602-3, but does not have the piezoelectric material 602-2, the sub-driving electrode 802, and the sensing electrode 700. In FIG7 or FIG8 , a blank area ER is provided at the connection between the second transmission element 604 and the first sub-actuating element 304. The blank area ER only has the transmission body 604-1 and the lower electrode 604-3, but does not have the piezoelectric material 604-2, the sub-driving electrode 804, and the sensing electrode 700. Since the connection point between the transmission element 600 and the first actuator element 300 is the maximum stress point in the mechanism, and the piezoelectric material is a brittle material that cannot withstand too much stress, a blank area ER is provided at the connection point between the transmission element 600 and the first actuator element 300, which helps to reduce the risk of damage to the piezoelectric actuator device 10.

FIG9 is an enlarged three-dimensional schematic diagram of the region R3 in FIG1. Referring to FIG9, in this embodiment, the second actuator 400 includes an actuator body 400-1, a piezoelectric material 400-2, and a lower electrode (not shown), wherein the lower electrode is disposed between the actuator body 400-1 and the piezoelectric material 400-2. The third transmission element 606 includes a transmission body 606-1, a piezoelectric material 606-2, and a lower electrode (not shown), wherein the lower electrode is disposed between the transmission body 606-1 and the piezoelectric material 606-2. In addition, two sub-driving electrodes may be disposed on the piezoelectric material of the transmission element 600. For example, as shown in FIG9 , a sub-driving electrode 806 and a sub-driving electrode 810 are disposed on the piezoelectric material 606-2 of the third transmission element 606. The sub-driving electrode 806 disposed on the first sub-actuating element 306 and the sub-driving electrode 810 disposed on the second actuator element 400 are extended and disposed on the third transmission element 606. In addition, the sub-driving electrode 806 and the sub-driving electrode 810 are disposed alternately along a direction parallel to the axis RA. Moreover, a blank area ER is disposed at the connection between the third transmission element 606 and the first sub-actuating element 306.

In addition, the first sub-actuating element 308 also includes (not shown) an actuating body, a piezoelectric material, and a lower electrode, and the lower electrode is disposed between the actuating body and the piezoelectric material. The fourth transmission element 608 also includes (not shown) a transmission body, a piezoelectric material, and a lower electrode, and the lower electrode is disposed between the transmission body and the piezoelectric material. Moreover, in one embodiment, the above-mentioned actuating bodies 302-1, 304-1, 306-1, 400-1, the sensing body 500-1, the transmission body 602-1, 604-1, 606-1 and the actuating body corresponding to the first sub-actuating element 308 and the transmission body of the second transmission element 608 are connected to each other and can be formed as one piece. The above-mentioned piezoelectric materials 302-2, 304-2, 306-2, 400-2, 500-2, 602-2, 604-2, 606-2 and the piezoelectric materials corresponding to the first sub-actuating element 308 and the second transmission element 608 are connected to each other and can be formed as one piece. The above-mentioned lower electrodes 302-3, 304-3, 306-3, 500-3, 602-3, 604-3 and the lower electrodes corresponding to the first sub-actuating element 308, the second actuator element 400, the third transmission element 606 and the fourth transmission element 608 are connected to each other and can be formed as one piece.

FIG10 is a three-dimensional schematic diagram of partial components of a piezoelectric actuator according to an embodiment of the present invention. FIG10 hides the reflective layer 1000, the sensing electrode 700, the driving electrode 800, the piezoelectric material and the lower electrode of the first actuator element 300, the piezoelectric material and the lower electrode of the second actuator element 400, and the piezoelectric material and the lower electrode of the sensing element in FIG3. Please refer to FIG3 and FIG10. In this embodiment, the piezoelectric actuator 10 further includes a reinforcement structure 1100, which is disposed on the second surface 200S2 of the rotating member 200 relative to the first surface 200S1. Among them, the reinforcement structure 1100 is ring-shaped. The provision of the reinforcement structure 1100 can enhance the rigidity of the rotating member 200.

FIG11 is a schematic diagram showing that a rotating member in a piezoelectric actuator according to an embodiment of the present invention reciprocates relative to a frame body with an axis as the center. FIG12 is a curve diagram showing that the rotation angle of the rotating member is relative to the driving voltage after the piezoelectric actuator according to an embodiment of the present invention receives a driving signal. FIG13 is a curve diagram showing that the sensing electrode in the piezoelectric actuator according to an embodiment of the present invention outputs a sensing signal and the sensing voltage is relative to the rotation angle of the rotating member. In FIG11 and FIG12, there is a good linear relationship between voltage and angle, and therefore, the rotation angle of the rotating member 200 in the piezoelectric actuator 10 according to an embodiment of the present invention can be well controlled. In FIG. 13 , the slope of the sensing voltage relative to the angle can reach 83 mV/degree. Therefore, in addition to allowing the sensing signal to more realistically present the degree of rotation of the rotating member 200, the piezoelectric actuator 10 can also effectively enhance the sensing capability of the piezoelectric actuator 10, and the piezoelectric actuator 10 has a large scanning angle and a high scanning frequency. The piezoelectric actuator 10 of this embodiment can be applied to projection imaging, for example. The scanning angle of the piezoelectric actuator 10 is the visible range of the screen, that is, the size of the screen. The scanning frequency determines the fill rate of the scanning track to the screen. The higher the scanning frequency, the higher the fill rate can be achieved, that is, the screen with a higher resolution can be presented.

In summary, in one embodiment of the present invention, the piezoelectric actuator device includes a rotating member, a first actuator element, a second actuator element, a transmission element, and a sensing element. The second actuator element and the sensing element are coupled to the rotating member via the transmission element. Moreover, the first actuator element, the second actuator element, the transmission element, and the sensing element are symmetrically arranged in the frame with the rotating member as the center, which helps to achieve the miniaturization of the piezoelectric actuator device. Therefore, the piezoelectric actuator device can achieve the effects of high control accuracy, large scanning angle, and high scanning frequency under the design of small component size. Moreover, since piezoelectric material is used as the material of the actuator element, the piezoelectric actuator device can also meet the requirements of easy mass production.

However, what is described above is only the preferred embodiment of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. That is, all simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the present invention are still within the scope of the patent of the present invention. In addition, any embodiment or patent application of the present invention does not need to achieve all the purposes, advantages or features disclosed by the present invention. In addition, the abstract and the title are only used to assist in the search of patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first", "second", etc. mentioned in this specification or patent application are only used to name the name of the element or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

10: Piezoelectric actuator

100:Frame

200: Rotating parts

200S1: First surface

200S2: Second surface

300: first actuating element

302, 304, 306, 308: first sub-actuating element

302-1, 304-1, 306-1, 400-1, : Actuating body

302-2, 304-2, 306-2, 400-2, 500-2, 602-2, 604-2, 606-2: piezoelectric materials

302-3, 304-3, 306-3, 500-3, 602-3, 604-3: lower electrode

400: Second actuating element

500:Sensing element

500-1: Sensing Subject

600: Transmission components

602: first transmission element

602-1, 604-1, 606-1: Transmission body

604: Second transmission element

606: third transmission element

608: Fourth transmission element

700: Sensing electrode

800: Driving electrode

802, 804, 806, 808, 810: sub-driving electrode

902, 904: elastic element

1000:Reflective layer

1100:Reinforcement structure

ER: Blank Area

O: Open

R1, R2, R3: Area

RA:Axis

RS: Rotating shaft structure

ST: Slotting

FIG. 1 is a schematic top view of a piezoelectric actuator according to an embodiment of the present invention. FIG. 2 is a schematic three-dimensional view of a piezoelectric actuator according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view along the section line A-A’ in FIG. 1 or FIG. 2. FIG. 4 is a schematic cross-sectional view along the section line B-B’ in FIG. 1 or FIG. 2. FIG. 5 is an enlarged three-dimensional view of region R1 in FIG. 1. FIG. 6 is a schematic cross-sectional view along the section line C-C’ in FIG. 5. FIG. 7 is an enlarged three-dimensional view of region R2 in FIG. 1. FIG. 8 is a schematic cross-sectional view along the section line D-D’ in FIG. 7. FIG. 9 is an enlarged three-dimensional view of region R3 in FIG. 1. FIG. 10 is a schematic three-dimensional view of a local component of a piezoelectric actuator according to an embodiment of the present invention. FIG. 11 is a schematic diagram of a rotating member in a piezoelectric actuator according to an embodiment of the present invention reciprocatingly swinging relative to a frame body with an axis as the center. FIG. 12 is a curve diagram of the rotation angle of the rotating member relative to the driving voltage after the piezoelectric actuator according to an embodiment of the present invention receives a driving signal. FIG. 13 is a curve diagram of the sensing voltage relative to the rotation angle of the rotating member when the sensing electrode in the piezoelectric actuator according to an embodiment of the present invention outputs a sensing signal.

10: Piezoelectric actuator

100:Frame

200: Rotating parts

300: First actuating element

302, 304, 306, 308: first sub-actuating element

400: Second actuator element

500:Sensing element

600: Transmission components

602: First transmission element

604: Second transmission element

606: The third transmission element

608: Fourth transmission element

700: Sensing electrode

800: Driving electrode

802, 804, 806, 808, 810: sub-driving electrodes

902, 904: elastic element

1000:Reflection layer

O: Open

R1, R2, R3: Area

RA: axis

RS: Rotating shaft structure

ST: slotting

Claims (17)

A piezoelectric actuator comprises: A frame having an opening; A rotating member located in the opening and connected to the frame via a rotating shaft structure, the rotating shaft structure having an axis, the rotating member being adapted to swing back and forth relative to the frame with the axis as the center; A first actuating element disposed between the frame and the rotating member, and the first actuating element being connected to the rotating member; A second actuating element disposed between the frame and the rotating member, and the second actuating element being connected to the frame; A sensing element disposed between the frame and the rotating member, and the sensing element being connected to the frame, the sensing element and the second actuating element being symmetrically disposed on opposite sides of the axis with the axis of the rotating shaft structure as the center; A plurality of transmission elements are disposed between the first actuating element and the second actuating element and between the first actuating element and the sensing element, and the second actuating element and the sensing element are coupled to the rotating member via the transmission elements; A sensing electrode is disposed on a portion of the transmission elements and the sensing element; and A driving electrode is disposed on another portion of the transmission element, the first actuating element, and the second actuating element. A piezoelectric actuator device as described in claim 1, wherein the first actuator element, the second actuator element, the sensing element and the transmission elements include piezoelectric materials. A piezoelectric actuator as described in claim 1, wherein the driving electrode is used to receive a driving signal to cause the second actuating element, the first actuating element and the transmission elements to deform, thereby driving the rotating element to rotate; wherein the sensing electrode is used to receive a sensing voltage generated by the sensing element being deformed accordingly due to the rotation of the rotating element, and output a sensing signal. A piezoelectric actuator device as described in claim 1, wherein the first actuator element includes a plurality of first sub-actuating elements, and the first sub-actuating elements are symmetrically arranged beside the rotating shaft structure with the axis of the rotating shaft structure as the center. A piezoelectric actuator device as described in claim 4, wherein the first sub-actuating elements are triangular in shape. A piezoelectric actuator as described in claim 1, wherein the second actuator element is U-shaped or C-shaped. A piezoelectric actuator as described in claim 1, wherein the transmission elements are symmetrically arranged on opposite sides of the axis with the axis of the rotating shaft structure as the center. A piezoelectric actuator device as described in claim 1, wherein the first actuator element includes a plurality of first sub-actuating elements, the transmission elements are respectively S-shaped or bent, and the transmission elements are connected between one of the first sub-actuating elements and one of the second actuator element and the sensing element. A piezoelectric actuator device as described in claim 1, wherein the first actuator element includes a plurality of first sub-actuating elements, the driving electrode includes five sub-driving electrodes, and the five sub-driving electrodes are respectively arranged on one of the first sub-actuating elements and the second actuator element, wherein the sub-driving electrode arranged on the second actuator element is extended and arranged on the transmission elements adjacent to the second actuator element. A piezoelectric actuator device as described in claim 9, wherein when the driving electrode receives a driving signal to cause the first actuator element and the second actuator element to drive the rotating member to rotate, among the sub-driving electrodes arranged on the first sub-actuating elements, the driving signals received by the sub-driving electrodes located on the same side of the axis of the rotating shaft structure have the same phase, and the driving signals received by the sub-driving electrodes located on different sides of the axis have opposite phases. A piezoelectric actuator device as described in claim 10, wherein the driving signal received by the sub-driving electrode disposed on the second actuator element and the driving signal received by the sub-driving electrodes disposed on the first sub-driving elements adjacent to the second actuator element have opposite phases. The piezoelectric actuator device as described in claim 1 further includes: An elastic element disposed between the frame and the first actuator element along the axis of the rotating shaft structure. A piezoelectric actuator as described in claim 1, wherein the rotating member has two slots, and the axis of the rotating shaft structure passes through the two slots. As described in claim 1, a piezoelectric actuator device, wherein a blank area is provided at the connection between the transmission elements and the first actuator element, and the blank area is an area where no piezoelectric material is provided. The piezoelectric actuator device as described in claim 1 further includes a reflective layer disposed on a first surface of the rotating element. The piezoelectric actuator device as described in claim 15 further includes: A reinforcement structure disposed on a second surface of the rotating member opposite to the first surface. A piezoelectric actuator as described in claim 16, wherein the reinforcement structure is ring-shaped.

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