CN117930493A

CN117930493A - Micro mirror device

Info

Publication number: CN117930493A
Application number: CN202211253464.4A
Authority: CN
Inventors: 虞涛
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-10-13
Filing date: 2022-10-13
Publication date: 2024-04-26

Abstract

The invention discloses a micro-mirror device, which comprises a reflecting mirror, driving arms and a supporting structure, wherein the upper surface of the reflecting mirror is a reflecting surface, the lower surface of the reflecting mirror is connected with a support column, each driving arm comprises a plurality of sections of cantilevers which are sequentially connected, each section of cantilevers deflects for a preset angle, each section of cantilevers comprises a piezoelectric driving element, one end of each driving arm is connected with the corresponding support column, the other end of each driving arm is connected with the corresponding supporting structure, a plurality of driving arms are arranged along the circumferential direction of the corresponding support column, and the driving arms are deformed by applying voltage to the piezoelectric driving elements so as to drive the reflecting mirror to deflect. The invention adopts a piezoelectric driving structure, has compact structure, easy manufacture and implementation, high driving efficiency, low loss, convenient control and good stability, and a single micro-mirror device only needs a simple circuit for driving without a complex driving circuit, thereby simplifying the complexity in the subsequent development of digital micro-mirror devices and reducing the cost.

Description

Micro mirror device

Technical Field

The present invention relates to the field of microelectromechanical systems, and in particular, to a micromirror device.

Background

A digital micromirror device (Digtial Micromirror Devices, DMD), which is a micro-electro-mechanical-MECHANICAL SYSTEM (MEMS) system with electronic input and optical output, is a core device of a DLP projection system, and is generally composed of hundreds of thousands to millions of micro-mirrors distributed in a matrix, each micro-mirror corresponds to a pixel, and the imaging pattern and its characteristics are determined by controlling the rotation and time domain response (determining the reflection angle and dead time of light) of the micro-mirror, which is a novel, all-digital device, and the micro-mirror array and CMOS SRAM are integrated on the same chip by using the MEMS technology. Each micromirror unit in the digital micromirror device is an independent unit, and can be turned over by different angles independently to reflect light to the illumination light path or the absorption light path, the main structure of the micromirror unit of the existing digital micromirror device comprises four layers, the first layer is a micromirror in a floating state, made of aluminum alloy, the second layer is a torsion beam-hinge connecting the micromirror, and the addressing electrode of the micromirror, the third layer is a metal layer, including the addressing electrode of the torsion beam, the bias/reset electrode, and the landing platform of the micromirror (limiting mirror deflection by ±12° or ±10°), the fourth layer is a static memory (RAM) using a standard CMOS process of a large scale integrated circuit, the micromirror is connected to the torsion beam, and the torsion beam is suspended on two hinge support posts by hinges, which are connected to the bias/reset electrode, which provides a bias voltage for each micromirror unit, there are two conductive channels for each micromirror unit, and the addressing electrode of the arm beam and the static memory of the digital micromirror are connected to the bottom layer of the torsion beam. In operation of the digital micromirror device, deflection (positive and negative) of the micromirror is individually controlled by changing binary states of the underlying CMOS control circuit and the lens reset signal, specifically, applying a bias voltage, wherein +5v (digital 1) is applied to one of the addressing electrodes and the other addressing electrode is grounded (digital 0), so that an electrostatic field is formed between the micromirror and the addressing electrode of the micromirror, the torsion beam and the addressing electrode of the torsion beam, thereby generating an electrostatic moment, causing the micromirror to rotate about the torsion beam until contacting the landing platform, and the micromirror unit will be locked in that position until the reset signal occurs. The existing digital micromirror device adopts an electrostatic control structure, and has low driving efficiency, high control difficulty and high complexity.

Disclosure of Invention

The invention aims to solve the technical problems and the technical task provided by the invention are to improve the prior art, provide a micro-mirror device and solve the problems of high control difficulty and high complexity of an electrostatic control structure adopted by a digital micro-mirror device in the prior art.

In order to solve the technical problems, the technical scheme of the invention is as follows:

The utility model provides a micromirror device, includes speculum, actuating arm and bearing structure, the upper surface of speculum is the reflecting surface, the lower surface of speculum is connected with the pillar, the one end and the pillar of actuating arm are connected, the other end and the bearing structure of actuating arm are connected, including piezoelectricity actuating element on the actuating arm, the actuating arm produces deformation and then drives based on piezoelectricity actuating element the speculum deflects. The micro-mirror device adopts a piezoelectric driving mode, has simple structure and good compactness, does not need the support of a traditional torsion beam, has small driving loss, is easy to manufacture, effectively reduces the control difficulty, can bend and deform the driving arm by applying voltage to the piezoelectric driving element, further realizes the rotation of the reflecting mirror, has convenient control and good stability, and only needs a simple circuit for driving, does not need a complex driving circuit, simplifies the complexity in the development of subsequent digital micro-mirror devices, and reduces the cost.

Further, a plurality of piezoelectric driving elements are arranged along the path direction of the driving arm, and the mechanical deformation of the adjacent piezoelectric driving elements is opposite to enable the driving arm to deform so as to drive the reflecting mirror to deflect. The mechanical deformation of the adjacent piezoelectric driving elements is opposite, so that the adjacent piezoelectric driving elements generate driving forces with opposite directions, and the positions of the driving arms where the adjacent piezoelectric driving elements are positioned are deformed reversely, so that the offset of the reflecting mirror in the transverse direction is controlled, and the reflecting mirror can deflect and incline and simultaneously keep the transverse offset of the central position of the reflecting mirror to be minimum as much as possible.

Further, voltages with the same waveforms but 180 degrees phase difference are applied to adjacent piezoelectric driving elements on the driving arm to generate opposite mechanical deformation, so that the driving arm is deformed to drive the reflecting mirror to deflect. The polarities of the voltages applied to the adjacent piezoelectric driving elements are opposite, so that the adjacent piezoelectric driving elements generate driving forces with opposite directions, the positions of the driving arms where the adjacent piezoelectric driving elements are located are deformed reversely, the deformation caused by the piezoelectric driving elements is sequentially overlapped along the path direction of the driving arms, and finally, the reflecting mirror deflects and tilts relative to an initial state.

Further, the driving arm is located directly below the lower surface of the mirror, and the driving arm does not exceed the projection area range when the mirror is not deflected. The structure is compact, the occupied space is small, the size of the whole micro-mirror device is equivalent to that of the reflecting mirror, the integration level can be improved, high resolution is realized on the DMD chip with small size, the details of the image are clearly and accurately displayed, and the distortion generated by the image in the imaging process is reduced.

Further, a plurality of driving arms are arranged along the circumferential direction of the strut, the driving arms are distributed in a central symmetry manner by taking the strut as a center, or the driving arms are distributed on two sides of the strut in an axisymmetric manner, the reflecting mirror is supported on the driving arms through the strut, the driving arms in the axisymmetric or central symmetric distribution can improve the supporting stability of the reflecting mirror, and the driving arms in the axisymmetric or central symmetric distribution cooperate with each other to ensure the balance and stability of the whole acting force when the reflecting mirror is driven to deflect and incline.

Further, the deflection angle between the adjacent cantilevers comprises one of 90 degrees and 360 degrees, and the cantilever has the advantages of simple structure, easy manufacture and control and good structural stability.

Further, a plurality of piezoelectric driving elements are arranged on the cantilever at intervals along the length direction of the cantilever, so that the cantilever can be deformed in a segmented mode, the deformation of the driving arm is more accurate and controllable, and finally the deflection and inclination control precision of the reflecting mirror is higher.

Furthermore, the piezoelectric driving element comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are arranged in a stacked mode, the structure is simple, voltage is applied to the first electrode layer and the second electrode layer, and deflection inclination of the reflecting mirror can be controlled by regulating the voltage and the voltage polarity.

Further, the driving arm comprises a substrate layer forming the whole path of the driving arm, the piezoelectric driving element is arranged on the substrate layer, and the substrate layer is used for supporting the piezoelectric driving element and is coupled with the piezoelectric driving element to convert the electrostrictive deformation of the piezoelectric driving element into the bending deformation of the whole driving arm for driving the reflecting mirror to deflect and incline.

Furthermore, the substrate layer is made of an elastic material, and the elastic material comprises one of silicon, silicon nitride and metal, so that the piezoelectric driving element can effectively deform, and the efficient driving reflector can deflect and incline.

Further, the supporting structure comprises a cavity positioned below the driving arm and the support column, the cavity provides a movable space for the driving arm to deform, the support column is ensured to be driven to deflect and incline, and then the deflection and incline of the reflecting mirror are realized.

Furthermore, the outer diameter of the reflecting mirror is 5-10 mu m, the structural size is small, the integration level can be effectively improved, and high resolution is realized.

Compared with the prior art, the invention has the advantages that:

The micro-mirror device adopts a piezoelectric driving structure, has compact structure, small occupied space, easy manufacturing and implementation, high driving efficiency, low loss, convenient control and good stability, and a single micro-mirror device only needs a simple circuit for driving without a complex driving circuit, thereby simplifying the complexity in the development of subsequent digital micro-mirror devices and reducing the cost.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a micromirror device according to a first embodiment of the invention;

FIG. 2 is a schematic diagram illustrating a hidden mirror structure of a micromirror device according to a first embodiment of the invention;

FIG. 3 is a schematic cross-sectional view of a cantilever;

FIG. 4 is a schematic diagram of a structure in which a plurality of piezoelectric driving elements are disposed on a cantilever;

FIG. 5 is a schematic diagram showing the overall structure of another micromirror device according to the first embodiment of the invention;

FIG. 6 is a schematic diagram illustrating a hidden mirror structure of another micro-mirror device according to the first embodiment of the present invention;

FIG. 7 is a schematic diagram of the overall structure of a micromirror device according to a second embodiment of the invention;

Fig. 8 is a schematic structural diagram of a hidden mirror of a micromirror device according to a second embodiment of the invention.

In the figure:

Mirror 1, support 11, drive arm 2, cantilever 21, piezoelectric drive element 22, first electrode layer 221, piezoelectric material layer 222, second electrode layer 223, substrate layer 23, support structure 3, and cavity 31.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The embodiment of the invention discloses a micromirror device which has the advantages of simple structure, good compactness, easy manufacture, convenient and simple control and high driving efficiency.

Example 1

As shown in fig. 1 and fig. 2, a micromirror device mainly includes a reflecting mirror 1, a driving arm 2 and a supporting structure 3, the upper surface of the reflecting mirror 1 is a reflecting surface, the lower surface of the reflecting mirror 1 is connected with a support 11, one end of the driving arm 2 is connected with the support 11, the other end of the driving arm 2 is connected with the supporting structure 3, a plurality of driving arms 2 are arranged along the circumference of the support 11, the driving arm 2 includes a plurality of sections of cantilevers 21 which are sequentially connected, deflection preset angles are formed between adjacent cantilevers 21, thereby forming an integral bending driving arm structure, each section of cantilevers 21 includes a piezoelectric driving element 22, the driving arm 2 is deformed by applying voltage to the piezoelectric driving element 22 so as to drive the reflecting mirror 1 to deflect, the piezoelectric driving element 22 on each section of cantilevers 21 independently works, when the piezoelectric driving element 22 is applied with voltage, the piezoelectric driving element 22 generates electrostrictive deformation, thus the bending deformation of the cantilevers 21 is caused, the driving arm 2 integrally generates required deformation, and then the driving arm 2 drives the support 11 to deflect the support 11 to perform the deflection on the reflecting mirror 1, the deflection control of the reflecting mirror is realized, the light path is simply or the light path is controlled in a small manner, the light path is required to be deflected in a small manner, the light path is simply and the light path is controlled in a small manner, and the light path is required to be deflected in a simple manner, and the light path is controlled by the light path is a reflection path 1, and the light path is easy to be controlled.

The reflector 1 is indirectly connected with the driving arm 2 through the support 11, in order to improve the structural compactness, reduce the occupied volume and improve the integration level, the driving arm 2 is positioned under the lower surface of the reflector 1, the driving arm 2 does not exceed the projection area range of the reflector 1 when not deflected, specifically, the support 11 is connected at the center of the lower surface of the reflector 1, the cross section size of the support 11 is smaller than the surface size of the reflector 1, the reflector 1 is connected at the top side of the support 11, the driving arm 2 is connected at the bottom side of the support 11, the driving arm 2 is positioned at the circumferential periphery of the support 11, and thus the driving arm 2 is positioned under the lower surface of the reflector 1, in addition, the distance between the driving arm 2 and the reflecting mirror 1 is arranged in the direction perpendicular to the surface of the reflecting mirror 1, so that the driving arm 2 cannot interfere with the reflecting mirror 1 when being deformed, in order to reduce the volume size of the micro-mirror device, the driving arm 2 does not exceed the projection area range when the reflecting mirror 1 is not deflected, namely, the connecting end of the driving arm 2 and the supporting structure 3 does not exceed the edge of the reflecting mirror 1, thus being beneficial to improving the integration level, a digital micro-mirror device for a DLP projection system comprises hundreds of thousands to millions of micro-mirror devices, each micro-mirror device corresponds to one pixel, and the smaller the size of the micro-mirror device is, the high resolution can be realized on a small-size chip, the volume of the projection system is beneficial to be reduced, and the development of miniaturization is satisfied.

The supporting structure 3 is an annular frame member surrounding the periphery of the driving arm 2, and of course, the supporting structure 3 is not limited to be an annular frame member, for example, two driving arms 2 are provided, and the supporting structure 3 may be formed by two independent fixing portions, where each fixing portion is connected to one driving arm 2. In this embodiment, the surface of the mirror 1 may be rectangular, or may be specifically square, or may be rectangular, and of course, the mirror 1 may also take other shapes, such as a circle, an ellipse, etc., taking the mirror 1 as an example for describing a square, the supporting structure 3 is a square ring frame, the size of the inner hollow area of the square ring frame is the same as the size of the surface of the mirror 1, that is, the side length of the inner hollow area of the supporting structure 3 is equal to the side length of the mirror 1, and the end of the driving arm 2 is connected to the edge of the inner hollow area of the supporting structure 3, so that the driving arm 2 does not exceed the projection area range of the mirror 1 when not deflected, ensuring structural compactness, and, in order to ensure that the driving arm 2 can freely deform without interference, the supporting structure 3 includes a cavity 31 below the driving arm 2 and the supporting post 11, that is, a movable space is required below the driving arm 2 and the supporting post 11, so that the driving arm 2 is a suspended structure is ensured, and the driving arm 1 is required to deflect, and the driving arm 2 is required to be partially raised, and the deflection of the driving arm is required to be deflected.

Specifically, the outer diameter of the reflecting mirror 1 is 5-10 μm, in this embodiment, the side length of the reflecting mirror 1 is 7.6 μm, the side length of the inner hollow area of the supporting structure 3 is 7.6 μm, the side length of the outer periphery of the supporting structure 3 is 8.3 μm, the reflecting mirror 1 does not exceed the outer periphery of the supporting structure 3 when deflecting and tilting, in the digital micro mirror device integrated with a plurality of micro mirror devices, the supporting structures 3 of adjacent micro mirror devices are connected together, the reflecting mirrors 1 of adjacent micro mirror devices have a spacing of 0.7 μm, the reflecting mirrors 1 of each micro mirror device do not interfere with each other, and the device can work independently and reliably, and ensure high integration, and realize high resolution on a small-size chip.

The piezoelectric driving element 22 is deformed by an inverse piezoelectric effect, that is, when a voltage is applied in the polarization direction of the piezoelectric material, the piezoelectric material deforms, and after the voltage is removed, the deformation of the piezoelectric material disappears. Specifically, as shown in fig. 3, the piezoelectric driving element 22 is of a composite material structure, and includes a first electrode layer 221, a piezoelectric material layer 222 and a second electrode layer 223 that are sequentially stacked, and three layers of materials are stacked and connected together by a deposition processing manner, where the first electrode layer 221 and the second electrode layer 223 are made of conductive materials, specifically, materials such as platinum and molybdenum, and the piezoelectric material layer 222 is made of materials such as barium titanate BT, lead zirconate titanate PZT, modified lead zirconate titanate, lead metaniobate, lead barium lithium niobate PBLN, modified lead titanate PT, lead magnesium niobate PMN, aluminum nitride AlN, scandium-doped aluminum nitride ScAlN, and the like, which are not limited in particular; in order to increase the mechanical strength of the driving arm 2, the driving arm 2 includes a substrate layer 23, the substrate layer 23 forms the whole path of the driving arm 2, the path of the substrate layer 23 is bent to form a plurality of cantilevers 21 connected in sequence, the piezoelectric driving element 22 is disposed on the substrate layer 23, the substrate layer 23 is used for supporting the piezoelectric driving element 22 and is coupled with the piezoelectric driving element 22, so that the piezoelectric driving element 22 can cause bending deformation of the substrate layer 23 when electrostriction deformation occurs, that is, the whole cantilever 21 is caused to bend and deform, the deformation of the plurality of cantilevers 21 connected in sequence is overlapped to finally cause the whole driving arm 2 to generate required deformation, and then drive the reflecting mirror 1 to deflect and incline, the substrate layer 23 is made of an elastic material, the elastic material can be silicon, silicon nitride or metal, the metal can be titanium or the like, and the substrate layer 23 can effectively bend and deform under the driving of the piezoelectric driving element 22, so as to drive the reflecting mirror 1 to deflect and incline.

Specifically, the driving arm 2 is entirely parallel to the mirror 1 that does not deflect and tilt, that is, when the driving arm 2 is not deformed, a plane formed by a meandering path of the driving arm 2 is parallel to the mirror 1 that does not deflect and tilt, the substrate layer 23, the first electrode layer 221, the piezoelectric material layer 222, and the second electrode layer 223 are sequentially stacked from bottom to top in a direction perpendicular to the surface of the mirror 1, or the first electrode layer 221, the piezoelectric material layer 222, the second electrode layer 223, and the substrate layer 23 may be sequentially stacked from bottom to top, that is, the piezoelectric driving element 22 may be disposed on the upper surface of the substrate layer 23, or the piezoelectric driving element 22 may be disposed on the lower surface of the substrate layer 23, without affecting the normal operation of the driving arm 2, a connection layer may be further disposed between the substrate layer 23 and the piezoelectric driving element 22, and the connection layer may be made of a material such as metallic titanium, or the like, where the connection layer is used to connect the piezoelectric driving element 22 to the substrate layer 23 more firmly.

The driving principle of the driving arm 2 is that the inverse piezoelectric effect of the piezoelectric material is utilized, voltage is applied to the polarization direction of the piezoelectric material, so that the piezoelectric material deforms to drive the whole cantilever 21 to deform, further, the driving arm 2 integrally generates required deformation, specifically, assuming that one end of the cantilever 21 is fixed, the first electrode layer 221 is grounded, the second electrode layer 223 is connected with positive voltage, the other end of the cantilever 21 is bent and deformed, if the first electrode layer 221 is grounded, the second electrode layer 223 is connected with negative voltage, the other end of the piezoelectric driving arm is bent and deformed in the opposite direction, the bending deformation of the cantilever 21 is related to the material characteristics of the piezoelectric material layer 222 and the magnitude and polarity of the voltage applied to the piezoelectric driving element 22, so that different deformations of the driving arm 2 can be realized by controlling the voltage applied to the piezoelectric driving element 22, and further, deflection tilting of the reflecting mirror 1 can be realized in different directions, namely, the deflection angle of the reflecting mirror 1 can be switched between three states of positive deflection angle, 0 degree and negative deflection angle can be realized, the deflection angle of the reflecting mirror 1 is related to the magnitude of the voltage applied to the piezoelectric driving element 22, and the deflection angle of the reflecting mirror 1 is controlled to be larger by applying the voltage to the piezoelectric driving element 22, and the deflection angle is larger than the driving element 1 is controlled.

In this embodiment, only one piezoelectric driving element 22 is disposed on each section of cantilever 21 of the driving arm 2, each section of cantilever 21 is in a straight strip shape, the piezoelectric driving element 22 is in a straight strip shape along the length direction of the cantilever 21, and the longer the length of the piezoelectric driving element 22 is, the larger the deformation amount is under the condition of the same applied voltage, so that the length of the piezoelectric driving element 22 is equivalent to the length of the cantilever 21, that is, the piezoelectric driving element 22 covers the whole length of the cantilever 21, so that the cantilever 21 can generate the maximum bending deformation amount, and the driving arm 2 can generate enough deformation in its entirety, and finally, the larger deflection inclination angle of the reflecting mirror 1 can be generated.

Further, in this embodiment, the driving arms 2 are in a U-shaped bending structure, that is, the adjacent cantilever arms 21 are connected by an arc-shaped connecting portion to form a U-shape, so that the deflection angle between the adjacent cantilever arms 21 is 360 degrees, which can also be expressed as that the adjacent cantilever arms 21 are in a parallel state, as shown in fig. 1 and fig. 2, the driving arms 2 may only include one U-shaped bending, the driving arms 2 may only include two cantilever arms 21, as shown in fig. 5 and fig. 6, the driving arms 2 may also include a plurality of U-shaped bending connected in turn, the driving arms 2 include three or more cantilever arms 21, the driving arms 2 are only provided with two driving arms 2 which are axisymmetrically distributed on two sides of the supporting post 11, that is, the driving arms 2 on two sides are identical in shape and structure, the driving arms 2 are connected to the same part on the circumference of the supporting post 11, the mirror 1 is driven to deflect and tilt by mirror-symmetrically deforming the driving arms 2 on both sides, and the deflection axis of the mirror 1 is perpendicular to the symmetry axis of the driving arms 2, and as illustrated in fig. 1 and 2, the normal direction of the surface of the mirror 1 when the mirror 1 is not deflected is defined as the Z-axis direction, the surface direction of the mirror 1 when the mirror 1 is not deflected is defined as the X-Y plane direction, more specifically, one side of the mirror 1 in square is defined as the X-axis direction, the other side of the mirror 1 in square is defined as the Y-axis direction, the symmetry axis between the two driving arms 2 is parallel to the X-axis direction, or expressed as the center line direction of the symmetry axis between the driving arms 2 along the side length of the mirror 1, the deflection axis of the mirror 1 is parallel to the Y-axis direction, or expressed as the direction of the centerline of the other side of the mirror 1 along which the deflection axis of the mirror 1 is along; referring to fig. 5 and 6, the normal direction of the surface of the mirror 1 when the mirror 1 is not deflected is defined as the Z-axis direction, the surface direction of the mirror 1 when the mirror 1 is not deflected is defined as the X-Y plane direction, more specifically, one side of the mirror 1 having a square shape is defined as the X-axis direction, the other side of the mirror 1 having a square shape is defined as the Y-axis direction, the symmetry axis between the two driving arms 2 is along the diagonal direction of the mirror 1, or expressed as that the symmetry axis between the two driving arms 2 is 45 degrees with respect to the X-axis, and the deflection axis of the mirror 1 is along the other diagonal direction of the mirror 1, or expressed as that the deflection axis of the mirror 1 is negative 45 degrees with respect to the X-axis.

Further, when the mirror 1 is driven to deflect, along the path direction of the driving arm 2, the adjacent piezoelectric driving elements 22 on each driving arm 2 apply voltages with the same waveforms but 180 degrees phase difference to make the adjacent piezoelectric driving elements 22 generate opposite mechanical deformation, so that the driving arm 2 is integrally deformed to drive the mirror 1 to deflect, the polarities of the voltages applied to the adjacent piezoelectric driving elements 22 are opposite, so that the mechanical deformation generated by the adjacent piezoelectric driving elements 22 is opposite, and further the bending deformation direction generated by the driving arm 2 is opposite due to the adjacent piezoelectric driving elements 22, in other words, when the previous section of cantilever 21 is bent downwards, the next section of cantilever 21 is bent upwards, in this way, in order to control the offset of the mirror 1 on the XY plane, the lateral offset generated by the bending deformation of each cantilever can be mutually offset, so that the lateral offset of the center position of the mirror 1 can be kept to the minimum as much as possible while the mirror 1 is deflected and inclined.

As shown in fig. 4, a plurality of piezoelectric driving elements 22 may be disposed on each section of cantilever 21 along the length direction thereof, each piezoelectric driving element 22 is independently controlled, so as to enable the cantilever 21 to perform finer deformation, the part covered by each piezoelectric driving element 22 on the cantilever 21 is correspondingly deformed under the action of each piezoelectric driving element 22, and the part of the cantilever 21 can be precisely deformed by applying voltages with different magnitudes or different voltage polarities on each piezoelectric driving element 22, so as to precisely control the integral deformation of the driving arm 2, and finally realize precise control of deflection inclination of the reflecting mirror 1, and avoid excessive optical axis offset of the optical path reflected by the reflecting mirror 1 due to excessive lateral offset of the reflecting mirror 1 in the plane direction thereof.

The manufacturing method of the micromirror device comprises the following steps:

The manufacturing method comprises the steps of manufacturing a substrate, wherein the substrate comprises a base layer, an insulating layer and a top layer which are sequentially laminated from bottom to top, the base layer is a silicon layer, the insulating layer can be made of insulating materials such as silicon dioxide, silicon nitride and aluminum oxide, the top layer is made of materials such as silicon, metal aluminum and titanium, the top layer is used for forming the base layer of a driving arm, and the base layer and the insulating layer are mainly used for forming a supporting structure and a cavity below the driving arm;

Sequentially growing each film layer of a first electrode layer, a piezoelectric material layer and a second electrode layer which are used for forming a piezoelectric driving element on the top layer in a deposition mode, wherein a film layer of a connecting layer can be formed between the piezoelectric driving element and the top layer through deposition;

Patterning each film layer of the piezoelectric driving element, etching the second electrode layer, the piezoelectric material layer and the first electrode layer sequentially from top to bottom to form the piezoelectric driving element, and then etching the film layer of the connecting layer to obtain a connecting layer below the piezoelectric driving element;

Patterning the top layer, and removing part of the top layer by etching to form a basal layer of the driving arm, so as to obtain the driving arm, a part for connecting the supporting column and an annular frame part for forming a supporting structure;

Depositing and growing a support and a reflecting mirror at a position for connecting the support, wherein the support and the reflecting mirror are made of metal materials, and specifically comprise platinum, aluminum and the like;

And sequentially etching the base layer and the insulating layer from the bottom surface of the substrate to obtain a supporting structure and a cavity below the driving arm, and finally obtaining the micromirror device.

Example two

As shown in fig. 7 and 8, the difference from the first embodiment is that the driving arms 2 are distributed in a central symmetry about the support 11, specifically, the deflection angle between the adjacent cantilevers 21 is 90 degrees, the lengths of the cantilevers 21 are sequentially shortened in the path direction from the support structure 3 to the support 11 on the driving arms 2, correspondingly, the lengths of the piezoelectric driving elements 22 are sequentially shortened, the driving arms 2 are integrally formed in a spiral shape, and the driving arms 2 are specifically provided with two driving arms 2 which are respectively connected to two opposite sides in the circumferential direction of the support 11 to form a central symmetry distribution.

In this embodiment, the control manner of the driving arms 2 is the same as that of the first embodiment, along the path direction of the driving arms 2, the adjacent piezoelectric driving elements 22 on each driving arm 2 apply voltages with the same waveforms but 180 degrees phase difference to deform the driving arms 2 so as to drive the reflecting mirror 1 to deflect, as shown in fig. 7 and 8, the surface normal direction of the reflecting mirror 1 when the deflection is not performed in the definition diagram is the Z-axis direction, the surface direction of the reflecting mirror 1 when the deflection is not performed is the X-Y plane direction, more specifically, one side of the reflecting mirror 1 in square shape is the X-axis direction, the other side of the reflecting mirror 1 in square shape is the Y-axis direction, and the two driving arms 2 are respectively connected to two sides of the supporting column 11 along the direction of the leg of the reflecting mirror 1, or expressed as that the connecting line direction of the connecting part of the two driving arms 2 and the supporting column 11 is 45 degrees with the X-axis, so that the deflection axis direction of the reflecting mirror 1 is along the other diagonal direction of the reflecting mirror 1, or expressed as that the deflection axis of the reflecting mirror 1 is 45 degrees minus the X-axis.

The foregoing is merely a preferred embodiment of the present invention, and it should be noted that the above-mentioned preferred embodiment should not be construed as limiting the invention, and the scope of the invention should be defined by the appended claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.

Claims

1. The utility model provides a micromirror device, its characterized in that includes speculum (1), actuating arm (2) and bearing structure (3), the upper surface of speculum (1) is the reflecting surface, the lower surface of speculum (1) is connected with pillar (11), the one end and the pillar (11) of actuating arm (2) are connected, the other end and the bearing structure (3) of actuating arm (2) are connected, including piezoelectric driving element (22) on actuating arm (2), actuating arm (2) are based on piezoelectric driving element (22) produce deformation and then drive speculum (1) deflection.

2. Micromirror device according to claim 1, characterized in that several piezo-electric driving elements (22) are arranged along the path direction of the driving arm (2), the mechanical deformations of adjacent piezo-electric driving elements (22) being opposite to deform the driving arm (2) to drive the mirror (1) to deflect.

3. Micromirror device according to claim 1, characterized in that adjacent piezoelectric driving elements (22) on the driving arm (2) are applied with voltages of the same waveform but 180 degrees out of phase to produce opposite mechanical deformations, which in turn deform the driving arm (2) to drive the mirror (1) to deflect.

4. Micromirror device according to claim 1, characterized in that the driving arm (2) is located directly below the lower surface of the mirror (1) and the driving arm (2) does not exceed the projection area of the mirror (1) when it is undeflected.

5. Micromirror device according to claim 1, characterized in that a plurality of driving arms (2) are arranged along the circumference of the support (11), the driving arms (2) being distributed symmetrically about the support (11) or the driving arms (2) being distributed axisymmetrically on both sides of the support (11).

6. Micromirror device according to claim 1, characterized in that the driving arm (2) comprises a plurality of cantilever arms (21) connected in sequence, the adjacent cantilever arms (21) being deflected by a predetermined angle, each cantilever arm (21) comprising a piezoelectric driving element (22).

7. The micromirror device according to claim 6, wherein the deflection angle between adjacent cantilevers (21) comprises one of 90 degrees and 360 degrees.

8. Micromirror device according to claim 6, characterized in that the cantilever (21) is provided with a plurality of piezo-electric driving elements (22) at intervals along its length.

9. The micromirror device according to any one of claims 1 to 8, wherein the piezoelectric driving element (22) comprises a first electrode layer (221), a piezoelectric material layer (222) and a second electrode layer (223) that are stacked.

10. Micromirror device according to any of claims 1 to 8, characterized in that the driving arm (2) comprises a substrate layer (23) constituting the entire path of the driving arm (2), the piezoelectric driving element (22) being arranged on the substrate layer (23).

11. Micromirror device according to claim 10, characterized in that the substrate layer (23) is made of an elastic material comprising one of silicon, silicon nitride and metal.

12. Micromirror device according to any one of claims 1 to 8, characterized in that the support structure (3) comprises a cavity (31) underneath the driving arm (2) and the post (11).

13. Micromirror device according to any of claims 1 to 8, characterized in that the outer diameter dimension of the mirror (1) is 5-10 μm.