A micromirror structure

Abstract

The application discloses a micro-mirror structure. The micro-mirror structure comprises a substrate, a reflecting mirror, a driving structure and a stress feedback structure. The substrate comprises a fixed frame, a fixed base plate, two rotating shafts and two driving beams. The fixed base plate is located in the fixed frame. The first side and the second side of the fixed base plate are connected with the fixed frame through a driving beam respectively. The third side and the fourth side of the fixed base plate are connected with the fixed frame through a rotating shaft respectively. The reflecting mirror is located on one side of the fixed base plate. The driving structure is located between the driving beam and the fixed frame and is connected with the driving beam and the fixed frame. The driving beam is used for applying pressure to the driving beam. The fixed base plate is driven by the driving beam to deflect along the rotating shaft. The stress feedback structure is located on the rotating shaft. The stress feedback structure is used for detecting the deformation amount of the rotating shaft. The application can realize accurate control of the position of the reflecting mirror, provide stress feedback, and improve the stability and reliability of the micro-mirror structure.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of microelectromechanical systems (MEMS) technology, and in particular to a micromirror structure. Background Technology

[0002] Micromirror structures are key optical components in microelectromechanical systems (MEMS). Their core function is to precisely control the direction of light by rapidly and controllably deflecting tiny mirrors. This capability makes them core components in modern optical systems such as lidar, projection displays, fiber optic communications, and biomedical imaging, directly determining the system's scanning accuracy, resolution, and response speed.

[0003] However, existing common lead zirconate titanate (PZT) driven micromirror structures typically employ a simple open-loop driving mode. For example, existing piezoelectric MEMS micromirrors are non-axial four-directional deflection micromirrors. This structure is characterized by its ability to deflect in four directions and its simple structure, but its steady state depends on the morphological balance control of the four piezoelectric elements. Moreover, the deflection lacks a feedback mechanism, and stress is concentrated at a few connection ends, making it prone to jitter during movement. It is evident that the mechanical structures of micromirrors in existing technologies often struggle to achieve precise and stable control of the mirror's attitude. Furthermore, due to the lack of a position feedback mechanism, the micromirror cannot correct errors caused by temperature changes, material creep, etc., during operation, thus limiting its long-term stability and reliability. Summary of the Invention

[0004] This invention provides a micromirror structure to achieve precise control of the position of the reflector and provide stress feedback, thereby improving the stability and reliability of the micromirror structure.

[0005] In a first aspect, embodiments of the present invention provide a micromirror structure, comprising: The substrate includes a fixed frame, a fixed substrate, two rotating shafts and two driving beams. The fixed substrate is located inside the fixed frame. The first and second opposite sides of the fixed substrate are respectively connected to the fixed frame by connecting one of the driving beams. The third and fourth opposite sides of the fixed substrate are respectively connected to the fixed frame by one of the rotating shafts. A reflector is located on one side of the fixed substrate; A driving structure is located between the driving beam and the fixed frame, and connects the driving beam and the fixed frame; the driving beam is used to apply pressure to the fixed base plate, thereby driving the fixed base plate to deflect along the rotation axis. A stress feedback structure is located on the rotation axis, and the stress feedback structure is used to detect the deformation of the rotation axis.

[0006] Furthermore, the first end of the drive beam is connected to the fixed substrate, the second end of the drive beam is connected to the drive structure, and the extension direction of the drive beam is parallel to the first side surface of the fixed substrate. The drive beam is also connected to the fixed frame via a fixed anchor point located between the first end and the second end of the drive beam.

[0007] Optionally, the distance between the fixed anchor point and the first end of the drive beam is a first distance, and the distance between the fixed anchor point and the second end of the drive beam is a second distance, wherein the ratio of the first distance to the second distance is 1:n; where n>0; The driving structure is specifically used to apply a first pressure to the correspondingly connected driving beam, and to apply a second pressure to the fixed substrate through the driving beam, so as to deflect along the rotation axis of the fixed substrate. The ratio of the first pressure to the second pressure is n:1.

[0008] Optionally, the drive beam includes a first drive beam and a second drive beam, and the drive structure includes a first piezoelectric drive structure and a second piezoelectric drive structure; The first end of the first drive beam is connected to the contact edge between the first side and the third side, and the second end of the first drive beam is connected to the first piezoelectric drive structure; the first end of the second drive beam is connected to the contact edge between the second side and the fourth side, and the second end of the second drive beam is connected to the second piezoelectric drive structure. The two rotation axes are located at the midpoints of the third side and the fourth side, respectively.

[0009] Optionally, the micromirror structure also includes a control module, which is connected to the drive structure and the stress feedback structure respectively. The control module is used to control the drive structure to apply a preset pressure to the drive beam, and to obtain the deformation of the rotation axis from the stress feedback structure. Based on the deformation of the rotation axis, the control module performs closed-loop control on the pressure applied by the drive structure to the drive beam.

[0010] Optionally, the stress feedback structure includes a piezoresistive feedback sensor and a piezoelectric feedback sensor; The piezoresistive feedback sensor and the piezoelectric feedback sensor are located on each of the rotating axes. The piezoresistive feedback sensor is used to detect the deformation of the rotating axis, and the piezoelectric feedback sensor is used to detect the deformation of the rotating axis.

[0011] Optionally, the shape of the fixing frame includes a square frame, the shape of the fixing substrate includes a square, and the fixing frame and the fixing substrate are made of the same material.

[0012] Optionally, the driving structure includes an insulating layer and a piezoelectric thin film layer, wherein the insulating layer is located between the piezoelectric thin film layer and the fixing frame.

[0013] Optionally, the piezoelectric thin film layer includes an upper electrode layer, a piezoelectric thin film material layer, and a lower electrode layer, wherein the piezoelectric thin film material layer is located between the upper electrode layer and the lower electrode layer, and the lower electrode layer is located on the side of the insulating layer away from the fixing frame.

[0014] Secondly, embodiments of the present invention also provide a multi-axis micromirror structure, including the micromirror structure in any embodiment of the present invention; the multi-axis micromirror structure further includes at least one peripheral fixing frame and a peripheral driving structure; The micromirror structure is located within at least one of the peripheral fixing frames, and within the at least one of the peripheral fixing frames, one of the peripheral fixing frames is connected to the micromirror structure via a connecting peripheral drive beam and a peripheral rotation shaft; the extending direction of the peripheral rotation shaft is different from the extending direction of the rotation shaft of the micromirror structure; The peripheral drive structure is located between the peripheral drive beam and the peripheral fixing frame, and connects the peripheral drive beam and the peripheral fixing frame. The peripheral drive structure is used to apply pressure to the peripheral drive beam, and drive the micromirror structure to deflect along the peripheral rotation axis through the peripheral drive beam.

[0015] This invention provides a micromirror structure comprising a substrate, a reflector, a driving structure, and a stress feedback structure. The substrate includes a fixed frame, a fixed base plate, two rotation axes, and two driving beams. The fixed base plate is located within the fixed frame. A first and second opposite side of the fixed base plate are connected to the fixed frame via driving beams, and a third and fourth opposite side of the fixed base plate are connected to the fixed frame via rotation axes. This allows the fixed base plate to deflect along the rotation axes when subjected to force applied by the driving beams. The reflector is located on one side of the fixed base plate. The driving structure is located between the driving beams and the fixed frame, connecting them. Pressure is applied to the driving beams, causing the fixed base plate to deflect along the rotation axes. By controlling the deflection of the fixed base plate, the deflection angle of the reflector can be controlled, thereby achieving precise position control of the reflector. The stress feedback structure detects the deformation of the rotation axes, providing stress feedback. This allows for closed-loop control of the reflector's position based on the stress feedback, improving the stability and reliability of the micromirror structure. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a micromirror structure provided in an embodiment of the present invention; Figure 2A schematic diagram of the front structure of the substrate provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of another micromirror structure provided in an embodiment of the present invention; Figure 4 A schematic diagram of the back side structure of the substrate provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the connection structure of the control module of the micromirror structure provided in an embodiment of the present invention; Figure 6 Provided for embodiments of the present invention Figure 3 A schematic diagram of the cross-sectional structure of the straight line MN in the diagram; Figure 7 Provided for embodiments of the present invention Figure 3 A schematic diagram of the cross-sectional structure of the straight line mn in the diagram; Figure 8 This is a schematic diagram of a multi-axis micromirror structure provided in an embodiment of the present invention. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0018] The micromirror structure provided in this embodiment of the invention, through a specially designed substrate structure and stress feedback mechanism, can achieve closed-loop control of the position of the mirror based on stress feedback, thereby enabling precise control of the mirror's position and improving the stability and reliability of the micromirror structure. Figure 1 This is a schematic diagram of a micromirror structure provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the front structure of the substrate provided in an embodiment of the present invention, as shown below. Figure 1 and Figure 2 As shown, the micromirror structure includes: The substrate 110 includes a fixing frame 111, a fixing substrate 112, two rotating shafts 113, and two driving beams 114. The fixing substrate 112 is located inside the fixing frame 111. The first side a and the second side b of the fixing substrate 112 are respectively connected to the fixing frame 111 via a driving beam 114. The third side c and the fourth side d of the fixing substrate 112 are respectively connected to the fixing frame 111 via a rotating shaft 113. A reflector 120 is located on one side of the fixing substrate 111.

[0019] Among them, such as Figure 1As shown, substrate 110 serves as the mechanical support and basic framework of the entire micromirror structure. Substrate 110 can be made of materials such as silicon, ceramics, glass, or quartz. The material of substrate 110 needs to be resistant to the PZT process, primarily requiring a temperature tolerance above 450 degrees Celsius. The fixing frame 111 within substrate 110 forms the outer framework of the micromirror structure, providing a stable anchoring interface for the fixing substrate 112. The fixing substrate 112 is a movable central platform located inside the fixing frame 111, capable of supporting the reflector 120. It is connected to the fixing frame 111 via two rotating shafts 113 and two drive beams 114, allowing the fixing substrate 112 to deflect relative to the fixing frame 111 as a reference plane. The reflector 120, as the core optical functional component of the micromirror structure, deflects synchronously with the fixing substrate 112 as it deflects around the rotating shafts 113, thereby achieving precise control of the light direction. The first side a and the second side b of the fixed substrate 112 are respectively connected to the fixed frame 111 by a drive beam 114. The third side c and the fourth side d of the fixed substrate 112 are respectively connected to the fixed frame 111 by a rotation axis 113. When a force is applied to the drive beam 114, the fixed substrate 112 can be deflected along the rotation axis 113.

[0020] A drive structure 130 is located between the drive beam 114 and the fixed frame 111, and connects the drive beam 114 and the fixed frame 111. The drive beam 114 is used to apply pressure, thereby driving the fixed base plate 111 to deflect along the rotation axis 113. A stress feedback structure 140 is located on the rotation axis 113, and the stress feedback structure 140 is used to detect the deformation of the rotation axis 113.

[0021] Specifically, the drive structure 130 is disposed in the area between the drive beam 114 and the fixed frame 111, and is connected to both the drive beam 114 and the fixed frame 111. Under the action of a control signal such as voltage, the drive structure 130 deforms, thereby applying a pushing or pulling force to the drive beam 114, which is then converted into a torque that causes the fixed substrate 112 to rotate around the rotation axis 113, thus achieving the deflection of the moving reflector. For example, the drive structure 130 can be a PZT piezoelectric film. By applying a voltage to the PZT piezoelectric film, it can be driven to deform, thereby generating a driving force applied to the drive beam 114. The stress feedback structure 140 is integrated on the rotation axis 113. When the drive structure 130 deflects the fixed substrate 112, the rotation axis 113 will undergo corresponding elastic bending deformation. The stress feedback structure 140 can sense and detect this deformation in real time, which can be in the form of strain, stress, or displacement. Since the elastic bending deformation on the rotating shaft 113 is directly related to the deflection angle of the fixed substrate 112, the deformation of the rotating shaft 113 detected by the stress feedback structure 140 is the feedback signal of the deflection angle or position of the fixed substrate 112 or the reflector 120. The signal form of the deformation of the rotating shaft 113 can be, for example, resistance or voltage change. The signal fed back by the stress feedback structure 140 can be used to construct a closed-loop control system. The force generated by the drive structure 130 acts on the drive beam 114. The drive beam pushes the fixed substrate 112, which elastically deflects around the rotating shaft 113, causing the reflector 120 to rotate. The stress feedback structure 140 detects the deformation of the rotating shaft 1113 and feeds the deformation signal back to the control module of the micromirror structure. The control module can adjust the drive signal and correct the drive command of the drive structure 130 in real time to achieve closed-loop control, thereby significantly improving the positioning accuracy, linearity and stability of the system.

[0022] This invention provides a micromirror structure comprising a substrate, a reflector, a driving structure, and a stress feedback structure. The substrate includes a fixed frame, a fixed base plate, two rotation axes, and two driving beams. The fixed base plate is located within the fixed frame. A first and second opposite side of the fixed base plate are connected to the fixed frame via driving beams, and a third and fourth opposite side of the fixed base plate are connected to the fixed frame via rotation axes. This allows the fixed base plate to deflect along the rotation axes when subjected to force applied by the driving beams. The reflector is located on one side of the fixed base plate. The driving structure is located between the driving beams and the fixed frame, connecting them. Pressure is applied to the driving beams, causing the fixed base plate to deflect along the rotation axes. By controlling the deflection of the fixed base plate, the deflection angle of the reflector can be controlled, thereby achieving precise control of the reflector's position. The stress feedback structure detects the deformation of the rotation axes, providing stress feedback. This allows for closed-loop control of the reflector's position based on the stress feedback, improving the stability and reliability of the micromirror structure.

[0023] In some embodiments of the present invention Figure 3 This is a schematic diagram of another micromirror structure provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the first end of the drive beam 114 is connected to the fixed base plate 112, and the second end of the drive beam 114 is connected to the drive structure 130. The extension direction of the drive beam 114 is parallel to the first side surface a of the fixed base plate 112. The drive beam 114 is also connected to the fixed frame 111 through a fixed anchor point 115, which is located between the first end and the second end of the drive beam 114.

[0024] Specifically, the main body of the drive beam 114 extends along a direction parallel to the first side a of the fixed substrate 112. The first side a is parallel to the second side b, the third side c is parallel to the fourth side d, and the third side c is perpendicular to the first side a, ensuring that the driving force generated by the drive structure 130 can be transmitted to the fixed substrate in the most effective direction. By setting the fixed anchor point 115 between the first end and the second end of the drive beam 114, and connecting the fixed anchor point 115 to the fixed frame 111, a lever structure is formed. The fulcrum of the lever structure is the fixed anchor point 115, thereby amplifying the torque of the drive structure 130. By setting the fixed anchor point 115 at different positions, when the force of the drive structure 130 is applied to the second end of the drive beam 114, generating displacement and pressure, the lever structure can amplify the displacement and pressure generated at the second end of the drive beam 114 and transmit them to the first end of the drive beam 114, acting on the fixed substrate 112. This achieves correction of the torque and further control of the displacement of the fixed substrate 112, realizing a wider range of torque control through the lever structure. The design of the fixed anchor point 115 in the drive beam 114 in some embodiments of the present invention not only provides stable mechanical support, but also optimizes the torque transmission efficiency from the drive structure 130 to the fixed base plate 112.

[0025] In some embodiments of the present invention, such as Figure 3 As shown, the distance between the fixed anchor point 115 and the first end of the drive beam 114 is the first distance, and the distance between the fixed anchor point 115 and the second end of the drive beam 114 is the second distance. The ratio of the first distance to the second distance is 1:n; where n>0.

[0026] The drive structure 130 is specifically used to apply a first pressure to the corresponding connected drive beam 114, and apply a second pressure to the fixed substrate 112 through the drive beam 114, so that the fixed substrate 112 deflects along the rotation axis 113. The ratio of the first pressure to the second pressure is n:1.

[0027] Specifically, the first end of the drive beam 114 is the connection end between the drive beam 114 and the fixed substrate 112, and the second end of the drive beam 114 is the connection end between the drive beam 114 and the drive structure 130. The range of n:1 can include 1:5 to 5:1, that is, the lever structure formed by the drive beam 114 can not only amplify the first pressure of the drive structure 130, but also reduce the first pressure, thereby improving the fine control of the torque and displacement of the fixed substrate 112. By matching different positions of the fixed anchor points 115 and controlling the displacement of the fixed substrate 112 by the drive structure 130, the rotational torque of the fixed substrate 112 can be corrected and the displacement controlled, so that the micromirror structure of the present invention can be applied to chip structures with more stroke angles, thus improving the application range of the micromirror structure of the present invention.

[0028] Optionally, the position of the fixed anchor point 115 on the drive beam 114 can be moved, and it can be fixed when it moves to a preset position, thereby further improving the fine control of the torque and displacement of the fixed base plate 112.

[0029] In some embodiments of the present invention, such as Figure 3 As shown, the drive beam 114 includes a first drive beam 1141 and a second drive beam 1142, and the drive structure 130 includes a first piezoelectric drive structure 131 and a second piezoelectric drive structure 132.

[0030] The first end of the first drive beam 1141 is connected to the contact edge between the first side a and the third side c, and the second end of the first drive beam 1141 is connected to the first piezoelectric drive structure 131; the first end of the second drive beam 1142 is connected to the contact edge between the second side b and the fourth side d, and the second end of the second drive beam 1142 is connected to the second piezoelectric drive structure 132; the two rotation axes 113 are located at the midpoint of the third side c and the midpoint of the fourth side d, respectively.

[0031] Specifically, the connection between the first end of the first drive beam 1141 and the fixed substrate 112 and the connection between the second end of the second drive beam 1142 and the fixed substrate 112 are diagonally opposite, so that the first drive beam 1141 can control the fixed substrate 112 to deflect in the direction of the contact edge between the first side a and the third side c, and the second drive beam 1142 can control the fixed substrate 112 to deflect in the direction of the contact edge between the second side b and the fourth side d. Furthermore, by controlling the first piezoelectric drive structure 131 and the second piezoelectric drive structure 132 to generate different magnitudes of force, the fixed substrate 112 can be further controlled to deflect along the rotation axis 113. Furthermore, the two rotation axes 113 are located at the midpoint of the third side c and the midpoint of the fourth side d, respectively, so that the fixed substrate 112 and the reflector 120 have a rotation axis, so that the fixed substrate 112 and the reflector 120 will not have vertical displacement, which can ensure the controllability of vertical aberration. This solves the technical problem in the prior art that the absence of a rotation axis causes positional aberrations in the incident and exit light from the reflector 120 due to vertical displacement.

[0032] also, Figure 4 This is a schematic diagram of the back side structure of the substrate provided in an embodiment of the present invention, as shown below. Figure 4 As shown, in the substrate 110, the fixed substrate 112, the two rotating shafts 113 and the two driving beams 114 have the same thickness, and the thickness of the fixed substrate 112, the two rotating shafts 113 and the two driving beams 114 is less than the thickness of the fixed frame 111, which facilitates manufacturing. For example, the thickness of the fixed substrate 112, the two rotating shafts 113 and the two driving beams 114 is 5-100um.

[0033] In some embodiments of the present invention, the mirror material of the reflector 120 is gold, aluminum, or other materials.

[0034] In some embodiments of the present invention Figure 5 This is a schematic diagram of the connection structure of the control module of the micromirror structure provided in an embodiment of the present invention, as shown below. Figure 5 As shown, the micromirror structure also includes a control module 150, which is connected to the drive structure 130 and the stress feedback structure 140 respectively. The control module 150 is used to control the drive structure 130 to apply a preset pressure to the drive beam 114, and to obtain the deformation of the rotation shaft 113 from the stress feedback structure 140. Based on the deformation of the rotation shaft 113, the control module 150 performs closed-loop control on the pressure applied by the drive structure 130 to the drive beam 114.

[0035] Specifically, the control module 150 outputs a specific control signal to the drive structure 130 to drive the drive structure 130 to generate corresponding deformation or force, thereby applying a preset pressure to the drive beam 114, causing the reflector 120 to deflect to a desired angle. The control module 150 obtains an electrical signal from the stress feedback structure 140 in real time. This signal directly reflects the real-time deformation of the rotating shaft 113 caused by the deflection of the fixed substrate 112 and the reflector 120. Since the deformation of the rotating shaft 113 and its torsion angle have a definite linear or functional relationship within the elastic range, this signal is essentially a high-precision feedback signal of the actual deflection angle of the mirror. The control module 150 compares the acquired actual deformation signal with the desired deformation signal. If there is a deviation between the two, the control module 150 can dynamically adjust the control signal output to the drive structure 130, thereby changing the pressure applied to the drive beam 114, so that the actual deformation converges to the desired deformation until the deviation is eliminated. This achieves high-precision and high-stability active control of the deflection of the reflector 120, which is different from the open-loop control micromirror structure in the prior art.

[0036] In some embodiments of the present invention, such as Figure 3 As shown, the stress feedback structure 140 includes a piezoresistive feedback sensor 141 and a piezoelectric feedback sensor 142; the piezoresistive feedback sensor 141 and the piezoelectric feedback sensor 142 are located on each rotating shaft 113. The piezoresistive feedback sensor 141 is used to detect the deformation of the rotating shaft 113, and the piezoelectric feedback sensor 142 is used to detect the deformation of the rotating shaft 113.

[0037] Specifically, a piezoresistive feedback sensor 141 is disposed on the surface of the rotating shaft 113. Based on the piezoresistive effect, when the rotating shaft 113 deforms due to the deflection of the fixed substrate 112 and the reflector 120, the resistance value of the piezoresistive strain gauge in the piezoresistive feedback sensor 141 changes. By measuring this resistance change, the deformation of the rotating shaft 113 can be accurately determined. A piezoelectric feedback sensor 142 is integrated on the rotating shaft 113. Based on the piezoelectric effect, when the rotating shaft 113 deforms, the stress acting on the piezoelectric material of the piezoelectric feedback sensor 142 causes polarization charges to be generated inside the material, thereby generating a measurable voltage or charge signal on the electrode. This voltage or charge signal reflects the magnitude of the deformation of the rotating shaft 113, thus realizing the deformation of the rotating shaft 113. The two feedback detection methods for the deformation of the rotating shaft 113 enable the control module 150 to fuse or cross-verify the deformation of the rotating shaft 113 detected by the two methods. This improves the reliability of the entire feedback system when a single sensor may have errors due to temperature drift, aging, or interference, and further enables precise control of the position of the reflector 130, thereby improving the stability and reliability of the micromirror structure.

[0038] In some embodiments of the present invention, the shape of the fixing frame 111 includes a square frame, the shape of the fixing substrate 112 includes a square, and the fixing frame 111 and the fixing substrate 112 are made of the same material.

[0039] Specifically, both the fixing frame 111 and the fixing substrate 112 are square in shape, and the side length of the square inside the fixing frame 111 is greater than the side length of the fixing substrate 112. This allows the fixing substrate 112 to be placed inside the fixing frame 111, facilitating the connection between the fixing frame 111 and the fixing substrate 112. By connecting the fixing substrate 112 to the fixing frame 111, the fixing frame 111 can be controlled to deflect along a fixed direction, preventing the fixing substrate 112 from shifting vertically and preventing the fixing substrate 112 from vibrating significantly during the deflection process.

[0040] In some embodiments of the present invention Figure 6 Provided for embodiments of the present invention Figure 3 A schematic diagram of the cross-sectional structure of the straight line MN in the figure, as shown below. Figure 6 As shown, the driving structure 130 includes an insulating layer 1301 and a piezoelectric thin film layer 1302, with the insulating layer 1301 located between the piezoelectric thin film layer 1302 and the fixing frame 111.

[0041] Specifically, the insulating layer 1301 ensures good insulation between the upper piezoelectric film layer 1302 and the fixing frame 111, preventing current leakage or electrical breakdown when a high driving voltage is applied, thus ensuring reliable device operation. The insulating layer 1301 can be made of silicon oxide. The piezoelectric film layer 1302 is a PZT piezoelectric film. When a driving voltage is applied to the piezoelectric film layer 1302, it will undergo lateral or longitudinal expansion and contraction deformation based on the inverse piezoelectric effect, thereby applying pressure to the driving beam 114. The driving beam 114 then drives the fixing substrate 111 to deflect along the rotation axis 113. The thickness of the insulating layer 1301 varies from 0.1 to 0.5 μm. A thicker insulating layer 1301 can provide higher voltage protection, but this will limit the deformation of the piezoelectric film layer 1302.

[0042] like Figure 6 As shown, the piezoelectric thin film layer 1302 includes an upper electrode layer 1302a, a piezoelectric thin film material layer 1302b, and a lower electrode layer 1302c. The piezoelectric thin film material layer 1302b is located between the upper electrode layer 1302a and the lower electrode layer 1302c, and the lower electrode layer 1302c is located on the side of the insulating layer 1301 away from the fixing frame 111.

[0043] Among them, such as Figure 6 As shown, the upper electrode layer 1302a is also provided with a first electrode 1303 and a second electrode 1304. The first electrode 1303 is in contact with the upper electrode layer 1302a, and the second electrode 1304 is in contact with the lower electrode layer 1302c through part of the upper electrode layer 1302a and the conductive material passing through the piezoelectric thin film material layer 1302b. The first electrode 1303 and the second electrode 1304 can be electrically connected to the control module 150 respectively, and the control module 150 applies a driving voltage to the upper electrode layer 1302a and the lower electrode layer 1302c.

[0044] Specifically, the upper electrode layer 1302a and the lower electrode layer 1302c of the piezoelectric thin film layer 1302 are made of conductive materials. The film thickness of the piezoelectric thin film layer 1302 is generally between 0.5um and 10um. A thicker piezoelectric thin film layer 1302 can provide a larger driving force. The piezoelectric thin film material layer 1302b can be made of ferroelectric ceramic materials with strong piezoelectric effect, such as lead zirconate titanate. When a driving voltage is applied between the upper electrode layer 1302a and the lower electrode layer 1302c, the piezoelectric thin film material layer 1302b will undergo transverse or longitudinal stretching deformation based on the inverse piezoelectric effect. This deformation will be converted into a pushing or pulling force on the driving beam 114. Then, through the lever action of the driving beam 114, the fixed substrate 111 and the reflector 120 will be driven to deflect around the rotation axis 113.

[0045] The piezoelectric feedback sensor 142 has the same structure as the drive structure 130, and is also composed of an insulating layer 1301, an upper electrode layer 1302a, a piezoelectric thin film material layer 1302b, and a lower electrode layer 1302c. Figure 7 Provided for embodiments of the present invention Figure 3 A schematic diagram of the cross-sectional structure of the straight line mn in the figure, as shown below. Figure 7 As shown, the piezoelectric feedback sensor 142 has the same film structure as the drive structure 130, and each film layer in the piezoelectric feedback sensor 142 is arranged on the rotating shaft 113 to detect the deformation of the rotating shaft 113.

[0046] Furthermore, an upper insulating layer can be disposed above the upper electrode layer 1302a. The upper insulating layer can dielectrically encapsulate the entire piezoelectric thin film layer 1302. The upper insulating layer typically uses the same material as the insulating layer 1301, such as silicon oxide or alumina from ALD. The upper insulating layer is provided to ensure stress balance at the upper and lower ends of the piezoelectric thin film layer 1302, preventing the initial state of the piezoelectric thin film layer 1302 from having high base stress.

[0047] This invention provides a micromirror structure. The substrate of the micromirror structure includes a fixed frame, a fixed substrate, two rotating axes, and two driving beams. When the fixed substrate is subjected to a force applied by the driving beams, it can deflect along the rotating axes. The driving structure applies pressure to the driving beams, which in turn drive the fixed substrate to deflect along the rotating axes. By controlling the deflection of the fixed substrate, the deflection angle of the reflector can be controlled, thereby achieving precise control of the reflector's position. The stress feedback structure can detect the deformation of the rotating axes, providing stress feedback. This allows for closed-loop control of the reflector's position based on the stress feedback, improving the stability and reliability of the micromirror structure.

[0048] This invention also provides a multi-axis micromirror structure. Figure 8 This is a schematic diagram of a multi-axis micromirror structure provided in an embodiment of the present invention, as shown below. Figure 8 As shown, the multi-axis micromirror structure includes the micromirror structure 10 of any of the above embodiments. The multi-axis micromirror structure also includes at least one peripheral fixing frame 210 and a peripheral driving structure 220.

[0049] The micromirror structure 10 is located within at least one peripheral fixing frame 210, and in the at least one peripheral fixing frame 210, one peripheral fixing frame 210 is connected to the micromirror structure 10 by connecting a peripheral drive beam 230 and a peripheral rotation shaft 240; the extension direction of the peripheral rotation shaft 240 is different from the extension direction of the rotation shaft of the micromirror structure 10.

[0050] The peripheral drive structure 220 is located between the peripheral drive beam 230 and the peripheral fixed frame 210, and connects the peripheral drive beam 230 and the peripheral fixed frame 210. The peripheral drive structure 220 is used to apply pressure to the peripheral drive beam 230, and drive the micromirror structure 10 to deflect along the peripheral rotation axis 240 through the peripheral drive beam 230.

[0051] Specifically, the micromirror structure provided in this embodiment includes the micromirror structure proposed in any of the above embodiments, and has the beneficial effects of the micromirror structure proposed in the above embodiments, which will not be repeated here. Furthermore, in the multi-axis micromirror structure of this embodiment, a peripheral fixing frame 210 is connected to the micromirror structure 10. By nesting a peripheral rotation axis 240, a peripheral drive beam 230, a peripheral drive structure 220, and a peripheral fixing frame 210 within the micromirror structure 10, the fixed substrate 112 and the reflector 120 in the micromirror structure 10 can deflect along the rotation axis 113, and also along the peripheral rotation axis 240. This allows the reflector 120 in the micromirror structure 10 to deflect in two dimensions, achieving dual-axis integration, thereby further enabling precise control of the deflection angle of the reflector 120. In addition, the peripheral rotation axis 240 can also be provided with a stress feedback structure in the micromirror structure 10 to provide feedback on deformation on the peripheral rotation axis 240. Furthermore, when there are multiple outer fixing frames 210, the size of the multiple outer fixing frames 210 increases sequentially, and the multiple outer fixing frames 210 can be nested in layers. The innermost outer fixing frame 210 has the smallest size, and a micromirror structure 10 is set inside the innermost outer fixing frame 210 to provide a multi-axis deflection scheme for the micromirror structure 10, thereby further realizing the fine control of the deflection angle of the reflector 120.

[0052] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A micromirror structure, characterized in that, include: The substrate includes a fixed frame, a fixed substrate, two rotating shafts and two driving beams. The fixed substrate is located inside the fixed frame. The first and second opposite sides of the fixed substrate are respectively connected to the fixed frame by connecting one of the driving beams. The third and fourth opposite sides of the fixed substrate are respectively connected to the fixed frame by one of the rotating shafts. A reflector is located on one side of the fixed substrate; A driving structure is located between the driving beam and the fixed frame, and connects the driving beam and the fixed frame; the driving beam is used to apply pressure to the fixed base plate, thereby driving the fixed base plate to deflect along the rotation axis. A stress feedback structure is located on the rotation axis, and the stress feedback structure is used to detect the deformation of the rotation axis.

2. The micromirror structure according to claim 1, characterized in that, The first end of the drive beam is connected to the fixed substrate, the second end of the drive beam is connected to the drive structure, and the extension direction of the drive beam is parallel to the first side surface of the fixed substrate. The drive beam is also connected to the fixed frame via a fixed anchor point located between the first end and the second end of the drive beam.

3. The micromirror structure according to claim 2, characterized in that, The distance between the fixed anchor point and the first end of the drive beam is the first distance, and the distance between the fixed anchor point and the second end of the drive beam is the second distance. The ratio of the first distance to the second distance is 1:n; where n>0. The driving structure is specifically used to apply a first pressure to the correspondingly connected driving beam, and to apply a second pressure to the fixed substrate through the driving beam, so that the fixed substrate deflects along the rotation axis. The ratio of the first pressure to the second pressure is n:

1.

4. The micromirror structure according to any one of claims 1-3, characterized in that, The drive beam includes a first drive beam and a second drive beam, and the drive structure includes a first piezoelectric drive structure and a second piezoelectric drive structure. The first end of the first drive beam is connected to the contact edge between the first side and the third side, and the second end of the first drive beam is connected to the first piezoelectric drive structure; the first end of the second drive beam is connected to the contact edge between the second side and the fourth side, and the second end of the second drive beam is connected to the second piezoelectric drive structure. The two rotation axes are located at the midpoints of the third side and the fourth side, respectively.

5. The micromirror structure according to claim 1, characterized in that, It also includes a control module, which is connected to the drive structure and the stress feedback structure respectively. The control module is used to control the drive structure to apply a preset pressure to the drive beam, and to obtain the deformation of the rotation shaft from the stress feedback structure. Based on the deformation of the rotation shaft, the control module performs closed-loop control on the pressure applied by the drive structure to the drive beam.

6. The micromirror structure according to claim 1, characterized in that, The stress feedback structure includes a piezoresistive feedback sensor and a piezoelectric feedback sensor; The piezoresistive feedback sensor and the piezoelectric feedback sensor are located on each of the rotating axes. The piezoresistive feedback sensor is used to detect the deformation of the rotating axis, and the piezoelectric feedback sensor is used to detect the deformation of the rotating axis.

7. The micromirror structure according to claim 1, characterized in that, The fixed frame has a square shape, the fixed substrate has a square shape, and the fixed frame and the fixed substrate are made of the same material.

8. The micromirror structure according to claim 1, characterized in that, The driving structure includes an insulating layer and a piezoelectric thin film layer, with the insulating layer located between the piezoelectric thin film layer and the fixing frame.

9. The micromirror structure according to claim 8, characterized in that, The piezoelectric thin film layer includes an upper electrode layer, a piezoelectric thin film material layer, and a lower electrode layer. The piezoelectric thin film material layer is located between the upper electrode layer and the lower electrode layer, and the lower electrode layer is located on the side of the insulating layer away from the fixing frame.

10. A multi-axis micromirror structure, characterized in that, The multi-axis micromirror structure includes the micromirror structure described in any one of claims 1-9; the multi-axis micromirror structure further includes at least one peripheral fixing frame and a peripheral driving structure. The micromirror structure is located within at least one of the peripheral fixing frames, and within the at least one of the peripheral fixing frames, one of the peripheral fixing frames is connected to the micromirror structure via a connecting peripheral drive beam and a peripheral rotation shaft; the extending direction of the peripheral rotation shaft is different from the extending direction of the rotation shaft of the micromirror structure; The peripheral drive structure is located between the peripheral drive beam and the peripheral fixing frame, and connects the peripheral drive beam and the peripheral fixing frame. The peripheral drive structure is used to apply pressure to the peripheral drive beam, and drive the micromirror structure to deflect along the peripheral rotation axis through the peripheral drive beam.

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