TWI861529B - Piezoelectric actuating apparatus - Google Patents

Abstract

A piezoelectric actuating apparatus including a frame, a rotatable element, an actuating structure and a sensing structure is provided. The rotatable element is disposed in an accommodating opening, and is connected to the frame via a rotating shaft structure. The rotatable element is configured to reciprocatingly swing relative to the frame with an axis of the rotating shaft structure as the center. The actuating structure is elastically coupled to the rotatable element via at least one first elastic component. The sensing structure is elastically coupled to the rotatable part via at least one second elastic component. The actuating structure is deformed by receiving a driving signal through a driving electrode, and drives the rotatable element to rotate with the axis as a central axis by the at least one first elastic component. The sensing structure is correspondingly deformed by the rotating rotatable element through the at least one second elastic component, and outputs a sensing signal through a sensing electrode.

Description

Piezoelectric actuator

The present invention relates to a piezoelectric actuator, and in particular to a piezoelectric actuator with sensing capability.

With the development of applications such as optical projection, optical communication and optical ranging radar, reflective micro-mirror components have become one of the development focuses in related fields. Compared with micro-mirror components made by precision machining technology, another type of micro-mirror components made by combining micro-electromechanical systems (MEMS) with semiconductor process integration technology has gradually become the mainstream due to its characteristics of mass production, miniaturization and integration with electronic circuits. According to different driving methods, micro-mirror components can be roughly divided into three types, namely electrostatic drive, electromagnetic drive and piezoelectric drive.

Due to the easy availability of manufacturing materials, the relatively mature semiconductor process technology and external assembly technology, the micro-mirror components currently on the market that are made using semiconductor process technology are mostly electrostatically driven or electromagnetically driven. However, due to considerations of electrostatic force, the distance between the multiple comb-shaped electrode structures used in electrostatic drive cannot be too far, resulting in the risk of electrode short circuit and increased process difficulty. Electromagnetic drive requires electroplating coils on the top of the micro-mirror and assembling magnets on the outside. In addition to increasing the difficulty of miniaturization of components, the process of ferromagnetic materials is also less easy to integrate with existing semiconductor processes.

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 knowledge that does not constitute the common knowledge in the relevant technical field. The content disclosed in the "Prior Art" section does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by the common knowledge in the relevant technical field before the application of the present invention.

The present invention provides a piezoelectric actuator having better ability and accuracy in sensing the deformation of a movable part.

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 actuator. The piezoelectric actuator includes a frame, a rotating member, an actuator structure and a sensing structure. The frame has a receiving opening and a first side and a second side defining the receiving opening and opposite to each other. The rotating member is disposed in the receiving opening and connected to the frame via a rotating shaft structure. The rotating shaft structure has an axis, and the rotating member is suitable for reciprocating relative to the frame with the axis as the center. The actuator structure extends from the first side of the frame and is located between the rotating member and the first side of the frame. The actuator structure is elastically coupled to the rotating member via at least one first elastic member. The actuating structure comprises an actuating body, a first piezoelectric material layer, and a driving electrode disposed on one side of the first piezoelectric material layer. The first piezoelectric material layer is disposed on the actuating body. The sensing structure extends from the second side of the frame and is located between the rotating member and the second side. The sensing structure is elastically coupled to the rotating member via at least one second elastic member. The sensing structure comprises a sensing body, a second piezoelectric material layer, and a sensing electrode disposed on one side of the second piezoelectric material layer. The second piezoelectric material layer is disposed on the sensing body. At least one first elastic member and at least one second elastic member are respectively disposed on opposite sides of the axis. The actuating structure receives a driving signal through the driving electrode to generate deformation, and drives the rotating member to rotate around the axis through at least one first elastic member. The rotating member generates corresponding deformation through at least one second elastic member to link the sensing structure, and outputs a sensing signal through the sensing electrode.

In one embodiment of the present invention, the piezoelectric actuator further includes a driving circuit and a sensing circuit. The driving circuit is coupled to the driving electrode to provide a driving signal. The sensing circuit is coupled to the sensing electrode to receive a sensing signal.

In one embodiment of the present invention, the rotating member of the piezoelectric actuator has a first side and a second side that are axially along the axis and opposite to each other. The rotating shaft structure includes a first part and a second part. The first part and the second part are respectively connected to the first side and the second side of the rotating member.

In one embodiment of the present invention, the at least one first elastic member of the piezoelectric actuator includes two first elastic members respectively disposed on the first side and the second side of the rotating member. The at least one second elastic member includes two second elastic members respectively disposed on the first side and the second side of the rotating member.

In one embodiment of the present invention, the actuation structure of the piezoelectric actuation device includes a first actuation arm and a second actuation arm which are respectively arranged on the first side and the second side of the rotating member and are separated from each other in structure. The first actuation arm and the second actuation arm are elastically coupled to the rotating member via two first elastic members, respectively.

In one embodiment of the present invention, the sensing structure of the piezoelectric actuator comprises a first sensing arm and a second sensing arm which are respectively arranged on the first side and the second side of the rotating member and are separated from each other in structure. The first sensing arm and the second sensing arm are elastically coupled to the rotating member via two second elastic members.

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

In one embodiment of the present invention, a reinforcement structure is provided on the second surface of the rotating member of the above-mentioned piezoelectric actuator.

In one embodiment of the present invention, the reinforcing structure of the rotating member of the above-mentioned piezoelectric actuator is a ring-shaped structure surrounding the edge of the rotating member.

In one embodiment of the present invention, the frame of the piezoelectric actuator further has a third side and a fourth side that define an accommodating opening and are opposite to each other. The third side and the fourth side intersect at the first side and the second side. The first part of the rotating shaft structure is further connected to the third side of the frame. The second part of the rotating shaft structure is further connected to the fourth side of the frame.

In one embodiment of the present invention, the width of the first part of the piezoelectric actuator increases gradually from the rotating member toward the third side in the extension direction along the third side. The width of the second part increases gradually from the rotating member toward the fourth side in the extension direction along the fourth side.

In one embodiment of the present invention, the rotating member of the above-mentioned piezoelectric actuator is provided with two slots in two regions adjacent to the first part and the second part of the rotating shaft structure, and the axis of the rotating shaft structure passes through the two slots.

In one embodiment of the present invention, a slot is provided at the connection between the first part of the rotating shaft structure of the above-mentioned piezoelectric actuator and the frame. Another slot is provided at the connection between the second part and the frame.

In one embodiment of the present invention, the frame of the piezoelectric actuator is provided with two slots in two regions adjacent to the first part and the second part of the rotating shaft structure, and the axis of the rotating shaft structure passes through the two slots.

In one embodiment of the present invention, the actuating body of the actuating structure of the piezoelectric actuating device, the sensing body of the sensing structure, at least one first elastic member, at least one second elastic member, the rotating shaft structure and the rotating member are integrally formed.

In one embodiment of the present invention, the actuation structure and the sensing structure of the above-mentioned piezoelectric actuation device are both half-moon shaped.

Based on the above, in a piezoelectric actuator of an embodiment of the present invention, a rotating member and an actuating structure and a sensing structure disposed on opposite sides of the rotating member are disposed in the receiving opening of the frame. The actuating structure can be electrically driven to generate deformation, and the rotating member is driven by the first elastic member to rotate relative to the frame around the axis of a rotating shaft structure. The rotating member can drive the sensing structure to generate corresponding deformation via the second elastic member, and the sensing structure in deformation outputs a corresponding sensing signal. Based on this, in addition to achieving a high degree of integration of the actuating structure, the rotating element and the sensing structure to realize the miniaturization of the piezoelectric actuator, the sensing signal obtained simultaneously when the rotating element is actuated can more realistically present the actual degree of rotation of the rotating element, which helps to improve the sensing ability of the piezoelectric actuator.

10, 20, 30: Piezoelectric actuator

100, 100A, 100B: Frame

100e1: First side

100e2: Second side

100e3: The third side

100e4: The fourth side

100op: Accommodation opening

120: Rotating parts

120a: first surface

120b: Second surface

120s1: First side

120s2: Second side

130, 130A: Rotating shaft structure

130p1, 130p1A: Part 1

130p2, 130p2A: Part 2

140, 140A: Actuation structure

140M, 140M-A: Actuator body

141: First actuator arm

142: Second actuator arm

160:Sensing structure

160M, 160M-A: Sensing body

161: First sensing arm

162: Second sensing arm

171, 171A: First elastic member

172, 172A: Second elastic member

180: Reinforcement structure

210:Drive circuit

220: Sensing circuit

AC: alternating current power

C1, C2: capacitors

DC: Direct current power supply

DE, DE-A: driving electrode

OPA: Operational Amplifier

PZL1, PZL1-A: first piezoelectric material layer

PZL2, PZL2-A: Second piezoelectric material layer

R: Resistor

RL: Reflective layer

RS1, RS2, RS3: slotting

RX: axis

SE, SE-A: Sensing electrode

W: Width

Figure 1 is a front view schematic diagram of a piezoelectric actuator according to the first embodiment of the present invention.

Figure 2 is a three-dimensional schematic diagram of the piezoelectric actuator of Figure 1.

Figure 3 is a partial enlarged view of the piezoelectric actuator of Figure 2.

FIG4 is a schematic cross-sectional view of the piezoelectric actuator of FIG2.

FIG5 is a schematic rear view of the piezoelectric actuator of FIG1.

Figure 6 is a partial enlarged view of the piezoelectric actuator in Figure 2 when it is actuated.

FIG. 7 is a graph showing the relationship between the rotation angle of the rotating member of FIG. 1 and the sensing signal at different operating frequencies.

Figure 8 is a graph showing the relationship between the sensing signal in Figure 7 and the rotation angle of the rotating member.

Figure 9 is a front view schematic diagram of a piezoelectric actuator according to the second embodiment of the present invention.

Figure 10 is a partially enlarged rear view of the piezoelectric actuator of Figure 9.

Figure 11 is a front view schematic diagram of a piezoelectric actuator according to the third embodiment of the present invention.

The other technical contents, features and effects of the present invention mentioned above 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 front view schematic diagram of a piezoelectric actuator according to the first embodiment of the present invention. FIG. 2 is a three-dimensional schematic diagram of the piezoelectric actuator of FIG. 1. FIG. 3 is a partially enlarged view of the piezoelectric actuator of FIG. 2. FIG. 4 is a cross-sectional schematic diagram of the piezoelectric actuator of FIG. 2. FIG. 5 is a rear view schematic diagram of the piezoelectric actuator of FIG. 1. FIG. 6 is a partially enlarged view of the piezoelectric actuator of FIG. 2 when actuated. FIG. 7 is a relationship diagram of the rotation angle of the rotating member of FIG. 1 and the sensing signal for different operating frequencies. FIG. 8 is a relationship diagram of the sensing signal of FIG. 7 to the rotation angle of the rotating member. FIG. 1 to FIG. 3 and FIG. 6 omit the drawing of the reflective layer RL of FIG. 4.

Referring to FIGS. 1 to 3 , the piezoelectric actuator 10 includes a frame 100 and a rotating member 120. The frame 100 has a receiving opening 100op and a first side 100e1 and a second side 100e2 that define the receiving opening 100op and are opposite to each other. The rotating member 120 is disposed in the receiving opening 100op and is connected to the frame 100 via a rotating shaft structure 130. The rotating shaft structure 130 has an axis RX, and the rotating member 120 is disposed on the axis RX, and the rotating member 120 is suitable for reciprocating relative to the frame 100 with the axis RX as the center.

In this embodiment, the rotating member 120 is, for example, a micro-plane reflector, and its outline is generally in the shape of a circular sheet, but is not limited thereto. In other embodiments not shown, the outline of the rotating member may also be a rectangle or other suitable polygon. In this embodiment, the rotating member 120 has a first side 120s1 and a second side 120s2 arranged axially along the axis RX and opposite to each other. The frame 100 also has a third side 100e3 and a fourth side 100e4 that define the accommodation opening 100op and are opposite to each other. That is, the first side 100e1, the second side 100e2, the third side 100e3 and the fourth side 100e4 are the four inner walls of the accommodating opening 100op of the frame 100, and the third side 100e3 and the fourth side 100e4 intersect (for example, are perpendicular to) the first side 100e1 and the second side 100e2 respectively. That is, the outline of the accommodating opening 100op defined by the four sides of the frame 100 of this embodiment can be a rectangle, but is not limited thereto.

In this embodiment, the rotating shaft structure 130 may include a first portion 130p1 and a second portion 130p2. The first portion 130p1 of the rotating shaft structure 130 connects the first side 120s1 of the rotating member 120 and the third side 100e3 of the frame 100. The second portion 130p2 connects the second side 120s2 of the rotating member 120 and the fourth side 100e4 of the frame 100. In particular, the arrangement direction of the first portion 130p1 and the second portion 130p2 of the rotating shaft structure 130 connected between the frame 100 and the rotating member 120 can define the axial direction of the axis RX of the rotating shaft structure 130. For example, in this embodiment, the axis RX may be perpendicular to the third side 100e3 and the fourth side 100e4 of the frame 100.

In order to drive the rotating member 120 to rotate around the axis RX, the piezoelectric actuator 10 further includes an actuator structure 140, which is disposed between the rotating member 120 and the first side 100e1 of the frame 100. More specifically, the actuator structure 140 extends from the first side 100e1 of the frame 100 into the receiving opening 1000p of the frame 100, and is spaced apart from the rotating member 120. In this embodiment, the contour of the actuator structure 140 facing the rotating member 120 (i.e., the side away from the first side 100e1 of the frame 100) is conformal to the contour of the rotating member 120. Therefore, the side of the actuating structure 140 facing the rotating member 120 may present a half-moon or semicircular outline, but is not limited thereto.

The actuating structure 140 may be elastically coupled to the rotating member 120 via two first elastic members 171. For example, in the present embodiment, one of the two first elastic members 171 is disposed at the first side 120s1 of the rotating member 120 and close to the first portion 130p1 of the rotating shaft structure 130, the other of the two first elastic members 171 is disposed at the second side 120s2 of the rotating member 120 and close to the second portion 130p2 of the rotating shaft structure 130, and the two first elastic members 171 are connected between the rotating member 120 and the actuating structure 140. In detail, the actuating structure 140 includes an actuating body 140M, a first piezoelectric material layer PZL1, and a driving electrode DE. The first piezoelectric material layer PZL1 is disposed on the actuating body 140M. The driving electrode DE is disposed on a side of the first piezoelectric material layer PZL1 away from the actuating body 140M. More specifically, the first piezoelectric material layer PZL1 is sandwiched between the actuating body 140M and the driving electrode DE (as shown in FIG. 3 ), and the actuating body 140M of the actuating structure 140 further has a first grounding electrode (not shown) coupled to the first piezoelectric material layer PZL1. One side of the actuating body 140M is connected to the first side 100e1 of the frame 100, and the two opposite ends of each first elastic member 171 are respectively connected to the rotating member 120 and the other side of the actuating body 140M, and the portion between the two opposite ends of each first elastic member 171 is bent into a plurality of U-shaped bends.

The piezoelectric actuator 10 may further include a driving circuit 210 (shown schematically in FIG. 1 ). The driving circuit 210 is coupled to the driving electrode DE of the actuating structure 140 to provide a driving signal. For example, the driving circuit 210 may be provided with an alternating current power source AC and a direct current power source DC, wherein one end of the alternating current power source AC is coupled to the driving electrode DE, and the other end is coupled to one end of the direct current power source DC, and the other end of the direct current power source DC is grounded. That is, the driving signal from the driving circuit 210 may be an alternating current voltage signal containing a DC offset, but is not limited thereto.

When the actuating structure 140 is grounded and the driving electrode DE is enabled by the driving circuit 210 and has a positive voltage, the first piezoelectric material layer PZL1 generates a compressive strain and drives the actuating body 140M to generate a contraction deformation. Please refer to FIG. 6 at the same time. At this time, the actuating structure 140 uses the side connected to the first side 100e1 of the frame as a supporting side and the other side thereof bends toward the direction where the driving electrode DE is provided (for example, bends upward relative to the frame 100), and drives the rotating member 120 to rotate along a direction with the axis RX of the rotating shaft structure 130 as the central axis through the two first elastic members 171.

Although not shown in the figure, it is not difficult to understand that when the actuating structure 140 is grounded and the driving electrode DE is enabled by the driving circuit 210 and has a negative voltage, the first piezoelectric material layer PZL1 will generate tensile strain and drive the actuating body 140M to generate tensile deformation, so that the actuating structure 140 uses the side connected to the first side 100e1 of the frame 100 as the supporting side and the other side thereof bends in the direction where the actuating body 140M is provided (for example, bends downward relative to the frame 100), and drives the rotating member 120 to rotate in the direction opposite to the rotation direction of the rotating member 120 in Figure 6 through the two first elastic members 171. When the driving electrode DE is enabled by the driving circuit 210 so that the driving electrode DE alternately has positive voltage and negative voltage, the rotating member 120 reciprocates by a preset angle with the axis RX as the center axis.

In order to synchronously and more realistically sense the actual rotation extent of the rotating member 120, the piezoelectric actuator 10 further includes a sensing structure 160 disposed between the rotating member 120 and the second side 100e2 of the frame 100. More specifically, the sensing structure 160 extends from the second side 100e2 of the frame 100 into the receiving opening 100op of the frame 100, and is spaced apart from the rotating member 120. In this embodiment, the profile of the sensing structure 160 facing the rotating member 120 (i.e., the side away from the second side 100e2 of the frame 100) is conformal to the profile of the rotating member 120. Therefore, the side of the sensing structure 160 facing the rotating member 120 may present a half-moon or semicircular outline, but is not limited thereto.

The sensing structure 160 can be elastically coupled to the rotating member 120 via two second elastic members 172. For example, in this embodiment, one of the two second elastic members 172 is disposed at the first side 120s1 of the rotating member 120 and close to the first portion 130p1 of the rotating shaft structure 130, the other of the two second elastic members 172 is disposed at the second side 120s2 of the rotating member 120 and close to the second portion 130p2 of the rotating shaft structure 130, and the two second elastic members 172 are connected between the rotating member 120 and the sensing structure 160. In detail, the sensing structure 160 includes a sensing body 160M, a second piezoelectric material layer PZL2, and a sensing electrode SE. The second piezoelectric material layer PZL2 is disposed on the sensing body 160M. The sensing electrode SE is disposed on a side of the second piezoelectric material layer PZL2 away from the sensing body 160M. More specifically, the second piezoelectric material layer PZL2 is sandwiched between the sensing body 160M and the sensing electrode SE (as shown in FIG. 3 ), and the sensing body 160M of the sensing structure 160 further has a second grounding electrode (not shown) coupled to the second piezoelectric material layer PZL2. One side of the sensing body 160M is connected to the second side 100e2 of the frame 100, and the two opposite ends of each second elastic member 172 are respectively connected to the rotating member 120 and the other side of the sensing body 160M, and the portion between the two opposite ends of each second elastic member 172 is bent into a plurality of U-shaped bends. In this embodiment, the actuating structure 140 and the sensing structure 160 are symmetrically arranged on two opposite sides of the rotating member 120.

The piezoelectric actuator 10 may further include a sensing circuit 220 (schematically shown in FIG. 1 ). The sensing circuit 220 is coupled to the sensing electrode SE of the sensing structure 160 to receive a sensing signal. For example, the sensing circuit 220 may include an amplifying circuit, and the amplifying circuit may include an operational amplifier OPA, a capacitor C1, a capacitor C2, and a resistor R. The capacitor C1 and the resistor R are connected in parallel to each other and are connected between the inverting input terminal of the operational amplifier OPA and the output terminal of the operational amplifier OPA, and the non-inverting input terminal of the operational amplifier OPA is grounded. The capacitor C2 is connected between the inverting input terminal of the operational amplifier OPA and the sensing electrode SE of the sensing structure 160. More specifically, the amplifier circuit of this embodiment is, for example, a charge amplifier, which is used to convert an AC current signal into an AC voltage signal, but is not limited thereto.

When the rotating member 120 is driven by the actuating structure 140 to rotate around the axis RX of the rotating shaft structure 130, the rotating member 120 can generate corresponding deformation by linking the sensing body 160M of the sensing structure 160 through the two second elastic members 172, and output a sensing signal to the sensing circuit 220 through the sensing electrode SE. For example, as shown in FIG. 1 , FIG. 3 and FIG. 6 , when a positive voltage is applied to the driving electrode DE located on one side of the axis RX, the upwardly bent actuating structure 140 drives the rotating member 120 to rotate clockwise around the axis RX through the first elastic member 171. At this time, the rotating rotating member 120 drives the second elastic member 172, so that the sensing structure 160 located on the other side of the axis RX is subjected to a tensile strain force to bend downward (not shown), and the applied tensile strain force will generate negative charge on the surface of the second piezoelectric material layer PZL2 connected to the sensing electrode SE, thereby generating a corresponding sensing signal to the sensing circuit 220.

That is, when the driving electrode DE of the actuating structure 140 is applied with a positive voltage to drive the rotating member 120 to rotate, the sensing electrode SE will have a negative voltage because the sensing structure 160 is deformed in the opposite direction to the actuating structure 140.

Since the actuating structure 140 and the first elastic member 171 are arranged symmetrically with the axis RX of the rotating shaft structure 130 as the center, the deformation stress of the actuating structure 140 can be more directly reflected in the deformation stress of the sensing structure 160 through the rotation of the rotating member 120. To further explain, the sensing circuit 220 and the driving circuit 210 can be coupled to a control unit (not shown). The control unit can adjust the driving signal of the driving circuit 210 according to the sensing signal from the sensing circuit 220. When the actuating structure 140 drives the rotating member 120 to rotate, the sensing structure 160 simultaneously outputs the corresponding sensing signal to the sensing circuit 220. The entire piezoelectric actuator 10 can use this synchronous feedback mechanism to make the reciprocating torsion of the rotating member 120 more precise, thereby improving the stability of the piezoelectric actuator 10. As shown in FIG. 7 and FIG. 8 , the sensing signal strength generated by the sensing structure 160 of the present embodiment for the rotation angle under different driving frequencies is roughly proportional to the rotation angle of the rotating member 120 under different driving frequencies. Therefore, in addition to allowing the sensing signal to more realistically present the degree of rotation of the rotating member 120, it can also effectively enhance the sensing capability of the piezoelectric actuator 10. In addition, the above-mentioned symmetrical arrangement can also achieve a high degree of integration of the rotating member 120, the actuating structure 140 and the sensing structure 160, which helps to realize the miniaturization of the piezoelectric actuator 10.

Please continue to refer to Figures 1 to 3. To further explain, in order to release the torsional stress generated at the connection between the rotating member 120 and the rotating shaft structure 130 during reciprocating rotation (torsion), the rotating member 120 is provided with two slots RS1 in two regions adjacent to the first portion 130p1 and the second portion 130p2 of the rotating shaft structure 130, and the axis RX of the rotating shaft structure 130 passes through the two slots RS1. Each slot RS1 is, for example, a through hole penetrating the rotating member 120 or a groove recessed relative to the surface of the rotating member 120.

On the other hand, a slot RS2 is provided at the connection between the first part 130p1 of the shaft structure 130 and the frame 100 (e.g., the third side 100e3), and another slot RS2 is provided at another connection between the second part 130p2 of the shaft structure 130 and the frame 100 (e.g., the fourth side 100e4), and the axis RX of the shaft structure 130 passes through these two slots RS2. Accordingly, the torsional stress generated at the connection between the shaft structure 130 and the frame 100 due to the reciprocating rotation of the rotating member 120 can be released. Each slot RS2 is, for example, a through hole that penetrates the first part 130p1/the second part 130p2.

It is worth mentioning that the first part 130p1 and the second part 130p2 of the rotating shaft structure 130 each have a slot RS2, so as to present a Y-shaped profile, wherein the first part 130p1 and the second part 130p2 each define two ends of the slot RS2 and are connected to the frame 100 respectively, so as to enhance the stability and anti-vibration ability of the rotating member 120 during reciprocating rotation.

Please refer to FIG. 4 and FIG. 5. In this embodiment, the actuating body 140M, the sensing body 160M, the rotating shaft structure 130, the first elastic member 171, the second elastic member 172 and the rotating member 120 can be selectively formed as one piece. The rotating member 120 has a first surface 120a and a second surface 120b which are opposite to each other, wherein the first surface 120a can be provided with a reflective layer RL, so that the light beam (not shown) incident to the rotating member 120 can have a better reflection efficiency through the reflective layer RL. On the other hand, in order to enhance the rigidity (or stiffness) of the rotating member 120, a reinforcing structure 180 can be provided on the second surface 120b of the rotating member 120. In this embodiment, the reinforcement structure 180 is, for example, an annular structure surrounding the edge of the rotating member 120, or an inner and outer annular structure surrounding the edge and center area of the rotating member 120 and a connecting rib is provided between the two annular structures (as shown in FIG. 5 ), but is not limited thereto.

It should be noted that in other embodiments not shown, the number of the first elastic member 171 connecting the rotating member 120 and the actuating structure 140 and the second elastic member 172 connecting the rotating member 120 and the sensing structure 160 can be adjusted according to different application designs, for example, one or more than three, as long as the symmetrical arrangement of the first elastic member 171 and the second elastic member 172 can be maintained.

The following will list some other embodiments to illustrate the present disclosure in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the aforementioned embodiments, and no further description will be given below.

FIG9 is a front view schematic diagram of a piezoelectric actuator according to the second embodiment of the present invention. FIG10 is a partially enlarged rear view of the piezoelectric actuator of FIG9. Referring to FIG9 and FIG10, the difference between the piezoelectric actuator 20 of this embodiment and the piezoelectric actuator 10 of FIG1 is that the configuration of the shaft structure is different. Specifically, in this embodiment, the first part 130p1A and the second part 130p2A of the shaft structure 130A each present a T-shaped profile.

More specifically, the width of the first portion 130p1A of the rotating shaft structure 130A in the extension direction along the third side 100e3 of the frame 100A gradually increases from the rotating member 120 toward the third side 100e3, and the width W (as shown in FIG. 10 ) of the second portion 130p2A in the extension direction along the fourth side 100e4 of the frame 100A gradually increases from the rotating member 120 toward the fourth side 100e4. Accordingly, the stability and anti-vibration capability of the rotating member 120 during rotation can be further enhanced.

In this embodiment, in order to release the torsional stress generated at the connection between the rotating shaft structure 130A and the frame 100A due to the reciprocating rotation of the rotating member 120, the frame 100 is provided with two slots RS3 in two regions adjacent to the first part 130p1A and the second part 130p2A of the rotating shaft structure 130A, and the axis RX of the rotating shaft structure 130A passes through the two slots RS3. Each slot RS3 is, for example, a through hole penetrating the frame 100A.

FIG11 is a front view schematic diagram of a piezoelectric actuator according to a third embodiment of the present invention. Referring to FIG11 , the main difference between the piezoelectric actuator 30 of this embodiment and the piezoelectric actuator 10 of FIG1 is that the configuration of the actuating structure and the sensing structure is different. Specifically, in this embodiment, the actuating structure 140A includes a first actuating arm 141 and a second actuating arm 142, which are respectively disposed on the first side 120s1 and the second side 120s2 of the rotating member 120 and are separated from each other in structure. The two opposite sides of the first actuating arm 141 are respectively connected to the first side 100e1 of the frame 100B and the first elastic member 171A, and the two opposite sides of the second actuating arm 142 are respectively connected to the first side 100e1 of the frame 100B and another first elastic member 171A, and the two first elastic members 171A are respectively elastically coupled to the first side 120s1 and the second side 120s2 of the rotating member 120.

Similarly, the sensing structure 160A includes a first sensing arm 161 and a second sensing arm 162 which are arranged on the first side 120s1 and the second side 120s2 of the rotating member 120 and are separated from each other in structure. The two opposite sides of the first sensing arm 161 are respectively connected to the second side 100e2 of the frame 100B and the second elastic member 172A, and the two opposite sides of the second sensing arm 162 are respectively connected to the second side 100e2 of the frame 100B and another second elastic member 172A, and the two second elastic members 172A are respectively elastically coupled to the first side 120s1 and the second side 120s2 of the rotating member 120.

Similar to the actuation structure 140 of FIG. 3 , the first actuation arm 141 and the second actuation arm 142 of the present embodiment each include an actuation body 140M-A, a first piezoelectric material layer PZL1-A and a drive electrode DE-A. The first piezoelectric material layer PZL1-A is sandwiched between the actuation body 140M-A and the drive electrode DE-A. The drive electrodes DE-A of the first actuation arm 141 and the second actuation arm 142 are electrically coupled to the drive circuit 210 to receive a drive signal. The first sensing arm 161 and the second sensing arm 162 each include a sensing body 160M-A, a second piezoelectric material layer PZL2-A and a sensing electrode SE-A. The second piezoelectric material layer PZL2-A is sandwiched between the sensing body 160M-A and the sensing electrode SE-A. The sensing electrodes SE-A of the first sensing arm 161 and the second sensing arm 162 are electrically coupled to the sensing circuit 220 to output a sensing signal.

Since the operating principles of the two actuating arms and the two sensing arms of this embodiment are similar to the actuating structure 140 and the sensing structure 160 of FIG. 1 , please refer to the relevant paragraphs of the aforementioned embodiment for detailed description, and will not be elaborated here.

In summary, in a piezoelectric actuator of an embodiment of the present invention, a rotating member and an actuating structure and a sensing structure symmetrically arranged on opposite sides of the rotating member are arranged in the receiving opening of the frame. The actuating structure can be driven to generate deformation, and the rotating member is driven by the first elastic member to reciprocate relative to the frame with the axis of a rotating shaft structure as the center. The rotating member can simultaneously drive the sensing structure to generate corresponding deformation via the second elastic member, and the sensing structure in deformation outputs a corresponding sensing signal. Based on this, in addition to achieving a high degree of integration of the actuating structure, the rotating element and the sensing structure to realize the miniaturization of the piezoelectric actuator, the sensing signal obtained simultaneously when the rotating element is actuated can more realistically present the actual rotation degree of the rotating element, which helps to improve the sensing capability of the piezoelectric actuator.

However, the 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 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 title are only used to assist in searching patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first" and "second" mentioned in this specification or patent application are only used to name 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:Framework

100e1: First side

100e2: Second side

100e3: The third side

100e4: The fourth side

1000p: Accommodation opening

120: Rotating parts

120s1: First side

120s2: Second side

130: Rotating shaft structure

130p1: Part 1

130p2: Part 2

140: Actuation structure

160:Sensing structure

171: First elastic member

172: Second elastic member

210:Drive circuit

220: Sensing circuit

AC: alternating current power

C1, C2: capacitors

DC: Direct current power supply

DE: driving electrode

OPA: Operational Amplifier

R: Resistor

RS1, RS2: slotting

RX: axis

SE: Sensing electrode

Claims (16)

A piezoelectric actuator comprises: a frame, a rotating member, an actuating structure and a sensing structure; wherein the frame has a receiving opening and a first side and a second side defining the receiving opening and opposite to each other; the rotating member is disposed in the receiving opening, and the rotating member is connected to the frame via a rotating shaft structure, and the rotating shaft structure is connected to the frame, and the rotating shaft structure has an axis, and the rotating member is suitable for rotating with the axis The actuating structure is configured to reciprocate relative to the frame with the first piezoelectric line as the center; the actuating structure extends from the first side of the frame and is located between the rotating member and the first side of the frame; the actuating structure is elastically coupled to the rotating member via at least one first elastic member, and the at least one first elastic member is connected to the rotating member; the actuating structure has an actuating body, a first piezoelectric material layer, and a driving electrode disposed on one side of the first piezoelectric material layer. A piezoelectric material layer is disposed on the actuating body; and the sensing structure extends from the second side of the frame and is located between the rotating member and the second side. The sensing structure is elastically coupled to the rotating member via at least one second elastic member. The sensing structure has a sensing body, a second piezoelectric material layer, and a sensing electrode disposed on one side of the second piezoelectric material layer. The second piezoelectric material layer is disposed on the sensing body. At least one first elastic member and at least one second elastic member are respectively arranged on opposite sides of the axis, wherein the actuating structure receives a driving signal through the driving electrode to generate deformation, and the at least one first elastic member drives the rotating member to rotate around the axis as the central axis. The rotating rotating member generates corresponding deformation by linking the sensing structure through the at least one second elastic member, and outputs a sensing signal through the sensing electrode. The piezoelectric actuator device as described in claim 1 further includes a driving circuit and a sensing circuit, wherein the driving circuit is coupled to the driving electrode to provide the driving signal, and the sensing circuit is coupled to the sensing electrode to receive the sensing signal. A piezoelectric actuator as described in claim 1, wherein the rotating member has a first side and a second side axially along the axis and opposite to each other, and the rotating shaft structure includes a first part and a second part, the first part is connected to the first side of the rotating member, and the second part is connected to the second side of the rotating member. The piezoelectric actuator device as described in claim 3, wherein the at least one first elastic member includes two first elastic members respectively disposed on the first side and the second side of the rotating member, and the at least one second elastic member includes two second elastic members respectively disposed on the first side and the second side of the rotating member. A piezoelectric actuator as described in claim 4, wherein the actuator structure includes a first actuator arm and a second actuator arm which are respectively arranged on the first side and the second side of the rotating member and are separated from each other in the structure, and the first actuator arm and the second actuator arm are respectively elastically coupled to the rotating member via the two first elastic members. The piezoelectric actuator device as described in claim 5, wherein the sensing structure includes a first sensing arm and a second sensing arm which are respectively arranged on the first side and the second side of the rotating member and are separated from each other in the structure, and the first sensing arm and the second sensing arm are respectively elastically coupled to the rotating member via the two second elastic members. The piezoelectric actuator device as described in claim 1 further includes a reflective layer disposed on a first surface of the rotating member. A piezoelectric actuator as described in claim 7, wherein a reinforcement structure is provided on a second surface of the rotating member. A piezoelectric actuator as described in claim 8, wherein the reinforcing structure of the rotating element is an annular structure surrounding the edge of the rotating element. The piezoelectric actuator device as described in claim 3, wherein the frame further has a third side and a fourth side that define the accommodating opening and are opposite to each other, the third side and the fourth side intersect at the first side and the second side, the first part of the rotating shaft structure is further connected to the third side of the frame, and the second part of the rotating shaft structure is further connected to the fourth side of the frame. A piezoelectric actuator as described in claim 10, wherein the width of the first portion in the extension direction along the third side gradually increases from the rotating member toward the third side, and the width of the second portion in the extension direction along the fourth side gradually increases from the rotating member toward the fourth side. A piezoelectric actuator as described in claim 11, wherein the rotating member is provided with two slots in two regions adjacent to the first portion and the second portion of the rotating shaft structure, respectively, and the axis of the rotating shaft structure passes through the two slots. A piezoelectric actuator as described in claim 11, wherein a slot is provided at the connection between the first part of the shaft structure and the frame, and another slot is provided at the connection between the second part and the frame. A piezoelectric actuator as described in claim 11, wherein the frame is provided with two slots in two regions adjacent to the first portion and the second portion of the rotating shaft structure, respectively, and the axis of the rotating shaft structure passes through the two slots. The piezoelectric actuator device as described in claim 1, wherein the actuator body of the actuator structure, the sensing body of the sensing structure, the shaft structure, the at least one first elastic member, the at least one second elastic member and the rotating member are integrally formed. A piezoelectric actuator as described in claim 1, wherein the side of the actuator structure facing the rotating member and the side of the sensing structure facing the rotating member are respectively in the shape of a half moon or a semicircle.

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