Micro-mirror structure and method for increasing maximum deflection angle

Abstract

The application relates to a micro-mirror structure and a method for increasing a maximum deflection angle, and belongs to the field of micro-electro-mechanical systems; the structure comprises a mirror and a deflection angle adjusting module located at the back of the mirror, and the deflection angle of the mirror is adjusted through the deflection angle adjusting module; the deflection angle adjusting module comprises an electric driving structure, a hinged structure and a supporting structure, the electric driving structure is opposite to the edge of the back of the mirror, the hinged structure is coupled to the back of the mirror, and the supporting structure is located between the electric driving structure and the hinged structure; an attractive force is applied to one side edge of the mirror through the electric driving structure, the mirror deflects to the attractive force side, the hinged structure deforms and generates a passive force opposite to the attractive force, further under the action of the supporting structure, the hinged structure deforms and the passive force reverses, and the mirror continues to deflect to the attractive force side around the supporting structure, so that the deflection angle is increased. The application solves the problem that the micron-level torsional micro-mirror cannot increase the deflection angle while eliminating the pull-in phenomenon in the prior art.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of micro-electro-mechanical system, and particularly relates to a micro-mirror structure and a method for increasing maximum deflection angle. BACKGROUND

[0002] Torsional micro-mirror is an optical device, which is mainly applied to modern optical communication, optical calculation, projection display, high-definition television and the like. With the development and optimization of digital micro-mirror device, the research on torsional micro-mirror is gradually reduced to micron level. The mirror surface length of the developed digital micro-mirror unit is reduced from 17 microns to 5.4 microns, and the filling rate of the device is increased by designing a multi-layer structure, and the deflection angle is increased from 10 degrees to 12 degrees and 17 degrees.

[0003] The maximum deflection angle of the torsional micro-mirror is related to optical efficiency. For example, the maximum deflection angle of the scanning mirror determines the scanning field of view, and the maximum deflection angle of the digital micro-mirror determines the illumination f number. When it is necessary to increase the deflection angle, the voltage is usually increased. However, increasing the maximum deflection angle by increasing the voltage will cause the pull-in phenomenon of the structure, that is, when the mirror deflects, it will produce a downward displacement. The conventional method for eliminating the pull-in phenomenon is to design the structure of the torsional micro-mirror and limit the voltage, so that the downward vertical displacement of the mirror is less than 1 / 3 of the distance between the mirror and the electrode. However, these methods will reduce the adjustment range of the deflection angle and reduce the optical efficiency of the micro-mirror unit.

[0004] Therefore, in order to ensure the filling rate of the device and eliminate the pull-in phenomenon by using a smaller voltage, the present application provides a micro-mirror structure and a method for increasing the maximum deflection angle. SUMMARY

[0005] Technical problems to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present application provides a micro-mirror structure and a method for increasing the maximum deflection angle. The deflection angle adjustment module of the structure adopts the lever principle, and the suction force generated by the electric driving structure 2, the passive force generated by the hinged structure 3 and the support structure 4 constitute a lever system, which can increase the deflection angle of the mirror 1 under smaller power. The present application solves the problem that the micron-level torsional micro-mirror cannot increase the deflection angle while eliminating the pull-in phenomenon in the prior art by designing the structure of the flexible beam 32 and the fulcrum position.

[0007] The technical scheme of the present application is: a micro-mirror structure, comprising a mirror 1 and a deflection angle adjustment module located at the back of the mirror 1, the deflection angle of the mirror 1 is adjusted by the deflection angle adjustment module;

[0008] The deflection angle adjusting module comprises an electric driving structure 2, a hinged structure 3 and a supporting structure 4, the electric driving structure 2 is opposite to the edge of the back surface of the mirror 1, the hinged structure 3 is coupled to the back surface of the mirror 1, and the supporting structure 4 is located between the electric driving structure 2 and the hinged structure 3;

[0009] The electric driving structure 2 is used for applying an attractive force to one side edge of the mirror 1 and driving the mirror 1 to move vertically and rotate around an axis;

[0010] The hinged structure 3 is located above the electric driving structure 2; the hinged structure 3 has a flexible area, which is used for limiting the degrees of freedom of the mirror 1, generating bending and torsional deformation and generating a passive force;

[0011] The mirror 1 is located above the hinged structure 3; during the vertical movement and the rotation around the axis of the mirror 1, the mirror 1 is in contact with the supporting structure 4 and changes the rotation axis, and the rotation axis is changed from the hinged structure 3 to the supporting structure 4;

[0012] The attractive force provided by the electric driving structure 2 and the passive force provided by the hinged structure 3 are located on both sides of the supporting structure 4 and do not overlap;

[0013] After the mirror 1 is in contact with the supporting structure 4, the attractive force, the passive force and the supporting structure 4 form a lever system, and the fulcrum is the supporting structure 4.

[0014] A further technical scheme of the present application is that the electric driving structure 2 of the deflection angle adjusting module comprises a first electrode 21 and a second electrode 22, an electrostatic force is generated by applying a voltage on the first electrode 21 and the second electrode 22, and the generation area of the electrostatic force is opposite to the side edge of the mirror 1 to be deflected, and the electrostatic force is the attractive force applied by the electric driving structure 2 to the edge of the mirror 1.

[0015] A further technical scheme of the present application is that the hinged structure 3 is suspended above the second electrode 22 through the supporting structure 4; the first electrode 21 is opposite to the edge of the back surface of the mirror 1 and serves as the generation area of the electrostatic force; and the mirror 1 is fixed to the top end of the hinged structure 3.

[0016] A further technical scheme of the present application is that the supporting structure 4 comprises a second supporting column 41, the bottom end of the second supporting column 41 is fixed to the second electrode 22, and the top end is connected to the outer edge of the hinged structure 3.

[0017] Alternatively, the support structure 4 comprises a second support column 41 and a fulcrum 42; the fulcrum 42 and the bottom end of the second support column 41 are fixed on the second electrode 22, the top end of the second support column 41 is connected with the outer edge of the hinged structure 3, the fulcrum 42 is not connected with the outer edge of the hinged structure 3, and the distance between the fulcrum 42 and the first support column 31 is greater than or equal to the distance between the second support column 41 and the first support column 31.

[0018] A further technical solution of the present application is that when the micro-mirror structure has the fulcrum 42, the back of the mirror 1 is deflected to contact the fulcrum 42 during movement, and when the micro-mirror structure does not have the fulcrum 42, the back of the mirror 1 is deflected to contact the second support column 41 during movement.

[0019] A further technical solution of the present application is that the hinged structure 3 of the deflection angle adjusting module comprises a first support column 31 and a flexible beam 32, the first support column 31 suspends the mirror 1 above the flexible beam 32, and the deflection of the mirror 1 drives the flexible beam 32 to produce torsional deformation and bending deformation.

[0020] A further technical solution of the present application is that the first support column 31 is connected between the back of the mirror 1 and the upper surface of the flexible beam 32.

[0021] When the flexible beam 32 is a central symmetric structure, the circumferential outer edge thereof is fixed to the top ends of four second support columns 41; the first support column 31 is located at the center of the flexible beam 32; when the mirror 1 is deflected, the first support column 31 transmits a torsional moment and a bending moment to the flexible beam 32, and the flexible beam 32 produces torsional deformation and bending deformation.

[0022] When the flexible beam 32 is a face symmetric structure, one side outer edge thereof is fixed to the top ends of two second support columns 41 away from the first electrode 21, and the other side is in a cantilever structure; the first support column 31 is located at the center of the cantilever end of the flexible beam 32; when the mirror 1 is deflected, the first support column 31 transmits a torsional moment and a bending moment to the flexible beam 32, and the flexible beam 32 produces torsional deformation and bending deformation.

[0023] A further technical solution of the present application is that the second support column 41 and the fulcrum 42 are a rectangular unit or a rectangular array.

[0024] A further technical solution of the present application is that the flexible beam 32 is coupled by a torsional beam 321 and a bending beam 322, wherein the torsional beam 321 is connected with the first support column 31 to provide a torsional moment, the bending beam 322 is coupled to the circumferential end of the torsional beam 31 and connected with the top end of the support structure 4 to provide a bending moment, and the cooperation of the torsional beam 321 and the bending beam 322 enables the mirror 1 to produce deflection and vertical displacement simultaneously under the action of electrostatic force.

[0025] A further technical solution of the present invention is: the stiffness of the flexible beam 32 is reduced by increasing the length of the torsion beam 321 and the bending beam 322, or by increasing the degrees of freedom of the flexible beam 32, so that it can undergo torsional and bending deformation under the traction of the reflector 1 and the first support column 31. The structure of the flexible beam 32 is as follows:

[0026] The extended curved beam 322 structure: the torsion beam 321 of the flexible beam 32 is a straight beam set in the middle, and the curved beam 322 is a wave-shaped cantilever beam coupled to both ends of the straight beam. The bending deformation and torsional deformation are increased by changing the amplitude and wavelength of the wave-shaped structure.

[0027] The extended torsion beam 321 structure: The torsion beam 321 of the flexible beam 32 is an X-shaped beam set in the middle, and the bending beam 322 is four V-shaped cantilever beams coupled to the four outer ends of the X-shaped beam. The bending deformation and torsion deformation are increased by changing the length or included angle of the beam arm of the X-shape.

[0028] The structure of the extended torsion beam 321 and the bending beam 322: The torsion beam 321 of the flexible beam 32 is formed by an X-shaped beam and four straight beams connected together in the middle, and the bending beam 322 is formed by four n-shaped beams coupled to the straight beams.

[0029] Increased freedom structure: The flexible beam 32 is a cantilever structure, with the end of the bending beam 322 fixed to the top of the two second support columns 41 away from the first electrode 21; the cantilever end of the torsion beam 321 is fixedly connected to the first support column 31, and its end is connected to the head of the bending beam 322; by changing the shape of the bending beam 322, its length is changed, thereby increasing bending deformation and torsional deformation.

[0030] A method for improving the maximum deflection angle using a micro-mirror structure, the specific steps of which are as follows:

[0031] The reflector 1 is suspended above the electrically driven structure 2 via the hinge structure 3;

[0032] A set voltage is applied to the electric drive structure 2 to generate electrostatic force at the edge of the side of the reflector 1 to be deflected;

[0033] The reflector 1 is subjected to electrostatic force, deflects around the hinge structure 3, and generates a downward vertical displacement, while simultaneously causing the hinge structure 3 to undergo torsional and bending deformation.

[0034] When the reflector 1 deflects to its back side and contacts the support structure 4, the set voltage continues to be applied to the electric drive structure 2, and the electrostatic force continues to act on the edge of the reflector 1.

[0035] Under the continuous action of electrostatic force, the reflecting mirror 1 continuously deflects, the torsional deformation of the hinged structure 3 continuously increases; the rotation axis changes from the hinged structure 3 to the support structure 4, the hinged structure 3 reverses the bending deformation and converts into the increment of the deflection angle, that is, the increase of the deflection angle is completed, the deformation area is increased by changing the shape of the hinged structure 3, and thus the upper limit of the deflection angle is increased.

[0036] A further technical scheme of the present application is that the rotation axis changes during the movement of the reflecting mirror 1.

[0037] When the reflecting mirror 1 deflects under the action of electrostatic force, the rotation axis is the flexible beam 32, and the reflecting mirror 1 deflects around the flexible beam 32.

[0038] When the reflecting mirror 1 deflects to the back surface and contacts the support structure 4, the reflecting mirror 1 deflects around the support structure 4.

[0039] A micromirror array includes a single micromirror structure or a plurality of micromirror structures arranged in an array, and the array is arranged in a rectangular array or a diamond array.

[0040] Advantages

[0041] The present application has the advantages that:

[0042] 1) The hinged structure is designed as a combination of a flexible beam and a support column, and the flexible beam is designed as a multi-section bending structure, the low rigidity of the flexible beam is utilized, and the size of the applied force during the operation is reduced, that is, the voltage amplitude applied to the electric drive structure during the deflection of the reflecting mirror is reduced.

[0043] 2) The present application proposes a method for increasing the maximum deflection angle by using a multi-layer structure to realize a torsional micromirror structure; the support structure is used as a fulcrum of the electrostatic force and the elastic force at the same time, the electrostatic force is used to swing the reflecting mirror by using the lever principle, and the maximum deflection angle is increased; during the movement, the rotation axis of the reflecting mirror changes from the hinged structure to the support structure, the downward vertical displacement gradually decreases and reverses, and finally converts into the increment of the deflection angle.

[0044] 3) The present application solves the pull-in phenomenon commonly existing in the torsional micromirror; the support structure is provided with the first electrode and the flexible beam on the two sides, the electrostatic force and the elastic force are located on the two sides of the support structure in the working state, the reflecting mirror contacts the support structure before approaching the first electrode, and the reflecting mirror moves away from the first electrode under the continuous action of the electrostatic force, so that the problem that the electrostatic force causes the pull-in phenomenon of the micromirror structure is solved; and simulation verification shows that the deflection angle change range of the torsional micromirror of the present application can be increased to 12°-35°. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 It is a schematic diagram of the movement mechanism of the micromirror structure of the present application.

[0046] Figure 2 Structure diagram of micro-mirror of the embodiment of the present application;

[0047] Figure 3 Structure diagram of electrode of micro-mirror of the embodiment of the present application;

[0048] Figure 4 Force analysis diagram of micro-mirror of the embodiment of the present application;

[0049] Figure 5 Structure position relation diagram of each component of the lengthened curved beam micro-mirror of the embodiment 1 of the present application;

[0050] Figure 6 Structure motion process diagram of the lengthened curved beam micro-mirror of the embodiment 1 of the present application;

[0051] Figure 7 Structure diagram of flexible beam of the embodiment 1 of the present application;

[0052] Figure 8 Independent fulcrum structure of the embodiment 1 of the present application; (a) position diagram of independent fulcrum, (b) top view of independent fulcrum structure;

[0053] Figure 9 Structure position relation diagram of each component of the lengthened torsional beam micro-mirror of the embodiment 2 of the present application;

[0054] Figure 10 Structure motion process diagram of the lengthened torsional beam micro-mirror of the embodiment 2 of the present application;

[0055] Figure 11 Structure diagram of flexible beam of the embodiment 2 of the present application;

[0056] Figure 12 Independent fulcrum structure of the embodiment 2 of the present application; (a) position diagram of independent fulcrum, (b) top view of independent fulcrum structure;

[0057] Figure 13 Comparison diagram of flexible beam and conventional flexible beam of the embodiment 1 and 2 of the present application; (a) conversion relation diagram between flexible beam and conventional flexible beam of the embodiment 1 and 2, (b) comparison diagram of electrostatic force and deflection angle of flexible beam and conventional flexible beam of the embodiment 1 and 2;

[0058] Figure 14 Structure position relation diagram of each component of the lengthened curved and torsional beam micro-mirror of the embodiment 3 of the present application;

[0059] Figure 15 Structure diagram of flexible beam of the embodiment 3 of the present application;

[0060] Figure 16 Structure position relation of each component of the cantilevered elongated flexure beam micro-mirror of the embodiment 4 of the present application;

[0061] Figure 17 Schematic diagram of the cantilevered flexure beam structure of the embodiment 4 of the present application;

[0062] Figure 18 Schematic diagram of the structure motion process of the cantilevered elongated flexure beam micro-mirror of the embodiment 4 of the present application;

[0063] Figure 19 Structure position relation of each component of the cantilevered elongated torsion beam micro-mirror of the embodiment 5 of the present application;

[0064] Figure 20 Schematic diagram of the cantilevered flexure beam structure of the embodiment 5 of the present application;

[0065] Figure 21 Schematic diagram of the structure motion process of the cantilevered elongated torsion beam micro-mirror of the embodiment 5 of the present application;

[0066] Figure 22 Comparison diagram of the flexure beam and the conventional flexure beam of the embodiments 4 and 5 of the present application;(a) conversion relation diagram between the flexure beam and the conventional flexure beam of the embodiments 1 and 2, (b) comparison diagram of the electrostatic force and the deflection angle of the flexure beam and the conventional flexure beam of the embodiments 1 and 2;

[0067] Figure 23 Schematic diagram of the micro-mirror array arrangement of the embodiments 6 and 7 of the present application;(a) row-column arrangement schematic diagram, (b) diamond arrangement schematic diagram;

[0068] Explanation of the reference signs: 1. reflecting mirror, 2. electric driving structure, 21. first electrode, 22. second electrode, 3. hinged structure, 31. first support column, 32. flexure beam, 321. torsion beam, 322. flexure beam, 4. support structure, 41. second support column, 42. fulcrum. DETAILED DESCRIPTION

[0069] The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0070] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0071] Based on the problem that the existing torsional micromirror cannot guarantee the effective area of the reflecting mirror 1 while eliminating the pull-in phenomenon, and cannot simultaneously improve the deflection angle of the reflecting mirror 1, the present application provides a micro-mirror structure, comprising a reflecting mirror 1 and a deflection angle adjusting module located at the back of the reflecting mirror 1, the deflection angle of the reflecting mirror 1 is adjusted through the deflection angle adjusting module;

[0072] The deflection angle adjusting module comprises an electric driving structure 2, a hinged structure 3 and a supporting structure 4, the electric driving structure 2 is opposite to the edge of the back of the reflecting mirror 1, the hinged structure 3 is coupled to the back of the reflecting mirror 1, and the supporting structure 4 is located between the electric driving structure 2 and the hinged structure 3;

[0073] The electric driving structure 2 is used to apply an attractive force to one side edge of the reflecting mirror 1 and drive the reflecting mirror 1 to move vertically and rotate around an axis;

[0074] The hinged structure 3 is located above the electric driving structure 2; the hinged structure 3 has a flexible area for limiting the degrees of freedom of the reflecting mirror 1, generating bending and torsional deformation, and generating a passive force;

[0075] The reflecting mirror 1 is located above the hinged structure 3; during the vertical movement and rotation around the axis of the reflecting mirror 1, the reflecting mirror 1 contacts the supporting structure 4 and changes the rotation axis, and the rotation axis is changed from the hinged structure 3 to the supporting structure 4;

[0076] The attractive force provided by the electric driving structure 2 and the passive force provided by the hinged structure 3 are located on both sides of the supporting structure 4 and do not overlap;

[0077] After the reflecting mirror 1 contacts the supporting structure 4, the attractive force, the passive force and the supporting structure 4 form a lever system, and the fulcrum is the supporting structure 4. Specifically, the electric driving structure 2 of the deflection angle adjusting module comprises a first electrode 21 and a second electrode 22, and an electrostatic force is generated by applying a voltage on the first electrode 21 and the second electrode 22, the generation area of the electrostatic force is opposite to the side edge to be deflected of the reflecting mirror 1, and the electrostatic force is the attractive force applied by the electric driving structure 2 to the edge of the reflecting mirror 1.

[0078] Specifically, the second electrode 22 is suspended above the hinge structure 3 by the support structure 4; the first electrode 21 is opposite to the edge of the back surface of the mirror 1, serving as an electrostatic force generating area; and the mirror 1 is fixed to the top end of the hinge structure 3.

[0079] Specifically, the support structure 4 comprises a second support column 41, the bottom end of which is fixed to the second electrode 22, and the top end of which is connected to the outer edge of the hinge structure 3.

[0080] Alternatively, the support structure 4 comprises a second support column 41 and a fulcrum 42; the fulcrum 42 and the bottom end of the second support column 41 are fixed to the second electrode 22, the top end of the second support column 41 is connected to the outer edge of the hinge structure 3, and the fulcrum 42 is not connected to the outer edge of the hinge structure 3.

[0081] Specifically, when the micro-mirror structure has the fulcrum 42, the back surface of the mirror 1 is deflected to contact the fulcrum 42 during movement; and when the micro-mirror structure does not have the fulcrum 42, the back surface of the mirror 1 is deflected to contact the second support column 41 during movement.

[0082] Specifically, the hinge structure 3 of the deflection angle adjusting module comprises a first support column 31 and a flexible beam 32, the first support column 31 suspends the mirror 1 above the flexible beam 32, and the deflection of the mirror 1 will cause the flexible beam 32 to produce torsional deformation and bending deformation.

[0083] Specifically, the distance between the fulcrum 42 and the first support column 31 is greater than or equal to the distance between the second support column 41 and the first support column 31.

[0084] Specifically, the first support column 31 is connected between the back surface of the mirror 1 and the upper surface of the flexible beam 32.

[0085] When the flexible beam 32 is a center-symmetrical structure, the circumferential outer edge thereof is fixed to the top end of four second support columns 41; the first support column 31 is located at the center of the flexible beam 32; and when the mirror 1 is deflected, the first support column 31 will transmit a torsional moment and a bending moment to the flexible beam 32, and the flexible beam 32 will produce torsional deformation and bending deformation.

[0086] When the flexible beam 32 is a face-symmetrical structure, one side of the outer edge thereof is fixed to the top end of two second support columns 41 away from the first electrode 21, and the other side is in a cantilever structure; the first support column 31 is located at the center of the cantilever end of the flexible beam 32; and when the mirror 1 is deflected, the first support column 31 will transmit a torsional moment and a bending moment to the flexible beam 32, and the flexible beam 32 will produce torsional deformation and bending deformation.

[0087] Specifically, the second support column 41 and the fulcrum 42 are a rectangular unit or a rectangular array.

[0088] Specifically, the flexible beam 32 is coupled by a torsion beam 321 and a bending beam 322, wherein the torsion beam 321 is connected with the first support column 31 to provide a torsion moment, and the bending beam 322 is coupled to the circumferential end of the torsion beam 31 and connected with the top end of the support structure 4 to provide a bending moment; the cooperation of the torsion beam 321 and the bending beam 322 enables the mirror 1 to produce deflection and vertical displacement simultaneously under the action of electrostatic force.

[0089] Specifically, the flexible beam 32 reduces the rigidity by increasing the length of the torsion beam 321 and the bending beam 322 or increasing the degree of freedom of the flexible beam 32, and produces torsional and bending deformation under the traction of the mirror 1 and the first support column 31. The structure of the flexible beam 32 is as follows:

[0090] The length of the bending beam 322 is increased: the torsion beam 321 of the flexible beam 32 is a straight beam arranged in the middle, and the bending beam 322 is a wave-shaped cantilever beam coupled to the two ends of the straight beam, and the bending deformation and the torsional deformation are increased by changing the amplitude and wavelength of the wave-shaped structure;

[0091] The length of the torsion beam 321 is increased: the torsion beam 321 of the flexible beam 32 is an X-shaped beam arranged in the middle, and the bending beam 322 is four V-shaped cantilever beams coupled to the four outer ends of the X-shaped beam, and the bending deformation and the torsional deformation are increased by changing the length of the beam arm or the included angle of the X-shaped beam;

[0092] The length of the torsion beam 321 and the bending beam 322 is increased: the torsion beam 321 of the flexible beam 32 is integrally connected with one X-shaped beam and four “-” shaped beams arranged in the middle, and the bending beam 322 is coupled to the four n-shaped beams of the “-” shaped beam;

[0093] The degree of freedom is increased: the flexible beam 32 is a cantilever structure, and the bending beam 322 is fixed to the top end of the two second support columns 41 away from the first electrode 21; the cantilever end of the torsion beam 321 is fixedly connected with the first support column 31, and the end thereof is connected with the head of the bending beam 322; the length of the bending beam 322 is changed by changing the shape thereof, and the bending deformation and the torsional deformation are increased.

[0094] The method for improving the maximum deflection angle of the micro-mirror structure of the application comprises the following specific steps:

[0095] The mirror 1 is suspended above the electric driving structure 2 through the hinged structure 3;

[0096] A set voltage is applied to the electric driving structure 2 to generate an electrostatic force at the edge of the side to be deflected of the mirror 1;

[0097] The mirror 1 is deflected around the hinge structure 3 by electrostatic force, and generates a downward vertical displacement, while driving the hinge structure 3 to generate torsional deformation and bending deformation;

[0098] When the mirror 1 is deflected to contact the back surface with the support structure 4, the set voltage continues to be applied to the electric driving structure 2, and the electrostatic force continuously acts on the edge of the mirror 1;

[0099] Under the continuous action of the electrostatic force, the mirror 1 continuously deflects, and the torsional deformation of the hinge structure 3 continuously increases; the rotation axis changes from the hinge structure 3 to the support structure 4, and the hinge structure 3 reverses the bending deformation to convert into an increment of the deflection angle, that is, the increase of the deflection angle is completed, and the deformation area is increased by changing the shape of the hinge structure 3, so that the upper limit of the deflection angle is increased.

[0100] Specifically, during the movement of the mirror 1, the rotation axis changes;

[0101] When the mirror 1 is deflected under the action of the electrostatic force, the rotation axis is the flexible beam 32, and the mirror 1 deflects around the flexible beam 32;

[0102] When the mirror 1 is deflected to contact the back surface with the support structure 4, the mirror 1 deflects around the support structure 4.

[0103] The micro-mirror array of the application comprises a single micro-mirror structure or a plurality of micro-mirror structures arranged in an array, and the array is arranged in a rectangular array or a diamond array.

[0104] The application deflects the mirror 1 by electrostatic attraction, and increases the maximum deflection angle by the lever structure formed by the electrostatic force generated by the support structure 4 and the electric driving structure 2 and the elastic force generated by the hinge structure 3.

[0105] The above technical solutions are further described below with reference to the accompanying drawings:

[0106] Embodiment 1:

[0107] Referring to Figure 1 The micro-mirror structure of the embodiment is a three-layer structure, and comprises, from top to bottom, a mirror 1, a flexible beam 32 and an electric driving structure 2. The electrode pair 5 is composed of a first electrode 21 and a second electrode 22, the mirror 1 and the flexible beam 32 are connected by a first support column 31, the flexible beam 32 and the electric driving structure 2 are connected by a support structure 4, and the support structure 4 comprises four second support columns 41 arranged in a rectangular array.

[0108] Referring to Figure 2 The electric driving structure 2 is composed of one second electrode 22 and two first electrodes 21, and the second electrode 22 is connected with the flexible beam 32 by four second support columns 41. The two first electrodes 21 are located on both sides of the second electrode 22, and do not exist onFigure 3 Regions ① and ② in the text.

[0109] Reference Figure 4 As shown, in this embodiment, the reflector 1 is deflected by electrostatic attraction generated by the electrode layer, and the maximum deflection angle is increased by the lever structure formed by the electrostatic force generated by the second support column 41 of the support structure 4, the electrostatic force generated by the electric drive structure 2, and the elastic force generated by the flexible beam 32. When no force is applied, the reflector 1 does not deflect. When a voltage is applied to the first electrode 21, the reflector 1 experiences an electrostatic force F1, resulting in deflection and a downward vertical displacement. Pulled by the reflector 1, the flexible beam 32 generates an upward elastic force F2, forming a force couple with F1, causing the reflector 1 to deflect until it contacts the support column.

[0110] After reflector 1 contacts the second support column 41, F1 continues to act on reflector 1, causing it to deflect around the second support column 41, and the deflection angle continues to increase. Due to the traction of reflector 1 and the restriction of the reflector's degree of freedom by the second support column 41, the flexible beam 32 generates a downward elastic force F2. At this time, F1, F2 and the second support column 41 form a lever structure, and the vertical displacement is converted into an increment of the deflection angle, increasing the maximum deflection angle.

[0111] Reference Figure 5 As shown, in this embodiment, the reflector 1 is mounted on top of the flexible beam 32 via the first support column 31, and the reflector 1, the first support column 31, and the flexible beam 32 are coaxially arranged. The flexible beam 32 is mounted on the second electrode 22 via four second support columns 41. The second electrode 22, the flexible beam 32, and the reflector 1 are equipotential bodies, forming an electrostatic field with the two first electrodes 21.

[0112] The flexible beam 32 is formed by integrally connecting one torsion beam 31 and two bending beams 32. By increasing the length of the bending beams 32 or the torsion beams 31, the overall hinge becomes a flexible beam structure that couples the bending-torsion beam and the folded beam. The bending beam 32 is connected to the first electrode 21 through four support columns, and the torsion beam 31 is connected to the reflector through support columns. The width of the connection can be slightly larger than the beam width.

[0113] Reference Figure 6 As shown, the movement of the reflector 1 in this embodiment is divided into two stages.

[0114] Phase 1: Reflector 1 is subjected to electrostatic force, resulting in two displacements: deflection and vertical displacement. Reflector 1 deflects and moves vertically downward until it contacts the second support column 41, at which point the second support column 41 provides support and stops the movement.

[0115] Second stage: the electrostatic force, the elastic force of the flexible beam 32 and the second support column 41 form a lever action, the top edge of the second support column 41 is the fulcrum, the mirror 1 is pried, the vertical displacement downward is gradually reduced and reversed, the deflection angle continues to increase. When the electrostatic force and the elastic force are equal, the mirror 1 gradually stops deflection, reaches the maximum deflection angle.

[0116] Referring to Figure 7 In the embodiment shown, the flexible beam 32 is integrally connected by a torsional beam 321 and two curved beams 322, and is centrally symmetric around the O point, symmetrically distributed along the x axis and the y axis. The torsional beam 321 is a straight beam, and the curved beam 322 is an integrated structure of two letters "n" and "one", which is approximately wave-shaped. In the process of displacement of the mirror 1, the flexible beam 32 simultaneously generates bending and torsion deformation.

[0117] Referring to Figure 8 In the embodiment shown, the second support column 41 and the fulcrum 42 can be arranged separately, and when the mirror deflects, the electrostatic force, the elastic force and the fulcrum 42 form a lever structure. The distance between the fulcrum 42 and the first support column 31 is greater than or equal to the distance between the second support column 41 and the first support column 31.

[0118] Embodiment 2:

[0119] The micro-mirror structure of the embodiment is the same as that of embodiment 1, and the difference lies in the structure of the flexible beam 32.

[0120] Referring to Figure 9 In the embodiment shown, the mirror 1 is installed above the flexible beam 32 through the first support column 2, and the mirror 1, the first support column 2 and the flexible beam 32 are coaxially arranged. The flexible beam 32 is installed on the second electrode 22 through the four second support columns 41, the second electrode 22, the flexible beam 32 and the mirror 1 are equipotential bodies, and form an electrostatic field with the two first electrodes 21.

[0121] Referring to Figure 10 In the embodiment shown, the movement process of the mirror 1 is divided into two stages.

[0122] First stage: the mirror 1 deflects and vertically moves downward to contact the second support column 41 under the action of the electrostatic force, and the top edge of the second support column 41 plays a supporting and stopping role.

[0123] Second stage: the electrostatic force, the elastic force of the flexible beam 32 and the second support column 41 form a lever action, the top edge of the second support column 41 is the fulcrum, the mirror 1 is pried, the vertical displacement downward is gradually reduced and reversed, the deflection angle continues to increase. When the electrostatic force and the elastic force are equal, the mirror 1 gradually stops deflection, reaches the maximum deflection angle.

[0124] Referring to Figure 11 and 12 As shown in the figure, the flexible beam 32 in the embodiment is integrally connected by one X-shaped torsion beam 321 and four V-shaped bending beams 322, and is centrally symmetric around the O point, symmetrically distributed along the x axis and the y axis, forming an "8" shape. In the process of displacement of the mirror 1, the flexible beam 32 simultaneously generates bending and torsion deformation.

[0125] Referring to Figure 13 As shown in the figure, when subjected to the same size electrostatic force F, the micro-mirror structures composed of (1), (2), and (3) are simulated, and the relationship between F and θ is shown in the figure. As can be seen from the figure, compared with structure (1), structures (2) and (3) with increased beam length can achieve a larger deflection angle.

[0126] Referring to Figure 12 As shown in the figure, in the embodiment, the second support column 41 and the fulcrum 42 can be arranged separately. When the mirror deflects, the electrostatic force and the elastic force form a lever structure with the fulcrum 42. The distance between the fulcrum 42 and the first support column 31 is greater than or equal to the distance between the second support column 41 and the first support column 31.

[0127] Embodiment 3:

[0128] The micro-mirror structure in the embodiment is consistent with the structure and motion process in Embodiment 1, and the difference lies in the structure of the flexible beam 32.

[0129] Referring to Figure 14 As shown in the figure, in the embodiment, the mirror 1 is installed above the flexible beam 32 through the first support column 2, and the mirror 1, the first support column 2, and the flexible beam 32 are coaxially arranged. The flexible beam 32 is installed on the second electrode 22 through four second support columns 41, and the second electrode 22, the flexible beam 32, and the mirror 1 are equipotential bodies, forming an electrostatic field with the two first electrodes 21.

[0130] Referring to Figure 15 As shown in the figure, in the embodiment, one X-shaped beam is integrally connected with four "I"-shaped beams to form a torsion beam 321, and is integrally connected with four n-shaped bending beams 322 to form a flexible beam 32, and is centrally symmetric around the O point, symmetrically distributed along the x axis and the y axis. In the process of displacement of the mirror 1, the flexible beam 32 simultaneously generates bending and torsion deformation.

[0131] Embodiment 4:

[0132] Referring to the flexible beam structure of Embodiment 1, the support structure 4 in the embodiment is composed of two second support columns 41 and two fulcrums 42, reducing the number of second support columns 41, and independently arranging the fulcrums 42, so that the double-end fixed beam becomes a single-end fixed beam, increasing the degree of freedom of the micro-mirror.

[0133] As shown in Figure 16 and 17 , the mirror 1 of the embodiment is installed above the flexible beam 32 through the first support column 31, and the mirror 1 and the first support column 31 are coaxially arranged, the flexible beam 32 is installed on the second electrode 22 through two second support columns 41, the second support columns 41 are independently fixed on the second electrode 22, the second electrode 22, the flexible beam 32 and the mirror 1 are equipotential bodies, and an electrostatic field is formed between the two first electrodes 21.

[0134] As shown in Figure 18 , the movement process of the mirror 1 of the embodiment is divided into two stages.

[0135] The first stage: the mirror 1 is deflected and vertically displaced by the electrostatic force. The mirror 1 is deflected and vertically moved downward to contact the support point 42, at which time the top edge of the support point 42 plays a supporting and stopping role.

[0136] The second stage: the electrostatic force, the elastic force of the flexible beam 32 and the support point 42 form a lever action, the mirror 1 is pried, the vertical displacement of the downward vertical displacement gradually decreases and reverses, and the deflection angle continuously increases. When the electrostatic force and the elastic force are equal, the mirror 1 gradually stops deflection and reaches the maximum deflection angle.

[0137] In the embodiment, the flexible beam 32 is integrally connected by a torsional beam 321 and a curved beam 322, and is symmetrically distributed along the x-axis. In the process of displacement of the mirror 1, the flexible beam 32 simultaneously generates bending and torsional deformation.

[0138] Embodiment 5:

[0139] Referring to the flexible beam structure of Embodiment 2, the support structure 4 of the embodiment is composed of two second support columns 41 and two support points 42, which reduces the number of second support columns 41, changes the double-end fixed beam into a single-end fixed beam, and increases the degree of freedom of the micro-mirror.

[0140] As shown in Figure 19 and 20 , the mirror 1 of the embodiment is installed above the flexible beam 32 through the first support column 31, and the mirror 1 and the first support column 31 are coaxially arranged, the flexible beam 32 is installed on the second electrode 22 through two second support columns 414, the support point 42 is independently fixed on the second electrode 22, the second electrode 22, the flexible beam 32 and the mirror 1 are equipotential bodies, and an electrostatic field is formed between the two first electrodes 21.

[0141] As shown in Figure 21 , the movement process of the mirror 1 of the embodiment is divided into two stages.

[0142] The first stage: the mirror 1 is deflected and vertically displaced by the electrostatic force. The mirror 1 is deflected and vertically displaced downward to contact the fulcrum 42, at which time the top edge of the fulcrum 42 supports and stops the mirror 1.

[0143] The second stage: the electrostatic force, the elastic force of the flexible beam 32 and the fulcrum 42 form a lever action, the mirror 1 is pried, the vertical displacement is gradually reduced and reversed, and the deflection angle continues to increase. When the electrostatic force and the elastic force are equal, the mirror 1 gradually stops deflection and reaches the maximum deflection angle.

[0144] In the embodiment, the flexible beam 32 is integrally connected with the two curved straight beams 32-b by one rhombic torsional beam 321 and symmetrically distributed along the x-axis. In the process of displacement of the mirror 1, the flexible beam 32 generates both bending and torsion deformation.

[0145] Referring to Figure 22 When subjected to the same size electrostatic force F, the micro-mirror structures composed of (4), (5) and (6) are simulated to obtain the relationship between F and θ as shown in the figure. As can be seen from the figure, compared with structure (4), structures (5) and (6) with increased beam length can achieve a larger deflection angle.

[0146] Embodiment 6:

[0147] Referring to the micro-mirror unit structure of Example 1, the micro-mirror array of the present embodiment is composed of a plurality of micro-mirror units. As shown in Figure 23 Fig. (a), the structure of the micro-mirror unit can be any one of Examples 1-4, and the micro-mirror array is composed of a plurality of micro-mirror units arranged in the row and column directions. The electrical driving structure of each micro-mirror unit in the micro-mirror array is independently controlled, and the deflection angle and direction of the mirror can be adjusted according to actual needs.

[0148] Embodiment 7:

[0149] Referring to the micro-mirror unit structure of Example 1, the micro-mirror array of the present embodiment is composed of a plurality of micro-mirror units. As shown in Figure 23 Fig. (b), the structure of the micro-mirror unit can be any one of Examples 1-4, and the micro-mirror array is composed of a plurality of micro-mirror units arranged in a rhombic shape, that is, one diagonal of each micro-mirror unit is parallel to the row direction, and the other diagonal of each micro-mirror unit is parallel to the column direction. The electrical driving structure of each micro-mirror unit in the micro-mirror array is independently controlled, and the deflection angle and direction of the mirror can be adjusted according to actual needs.

[0150] The present application simultaneously utilizes the lever principle and the flexible beam structure. The flexible beam structure increases the upper limit of the deflection angle and reduces the size of the electrostatic force. The lever principle eliminates the pull-in phenomenon of the torsional micromirror and converts the downward vertical displacement into upward vertical displacement, which is ultimately converted into the increment of the maximum deflection angle.

[0151] Under the same electrostatic force, the flexible beam can produce a larger deformation than the straight beam. The torsional deformation can increase the deflection angle of the mirror, while the bending deformation can reduce the distance between the mirror and the electrode, thereby reducing the deflection angle and increasing the risk of electrostatic breakdown. The present application uses a lever structure to eliminate the downward vertical displacement caused by the bending deformation and convert it into upward vertical displacement, which is ultimately converted into the increment of the maximum deflection angle.

[0152] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above-described embodiments without departing from the principles and purposes of the present application within the scope of the present application.

Claims

1. A micromirror structure, characterized in that: Includes a reflector (1) and a deflection angle adjustment module located on its back, the deflection angle of the reflector (1) is adjusted by the deflection angle adjustment module; The deflection angle adjustment module includes an electric drive structure (2), a hinge structure (3) and a support structure (4). The electric drive structure (2) is opposite to the edge of the back of the reflector (1), the hinge structure (3) is coupled to the back of the reflector (1), and the support structure (4) is located between the electric drive structure (2) and the hinge structure (3). The electric drive structure (2) is used to apply suction to one side edge of the reflector (1) and drive the reflector (1) to translate vertically and rotate about an axis; The hinge structure (3) is located above the electric drive structure (2); the hinge structure (3) has a flexible region for restricting the degree of freedom of the reflector (1); the hinge structure (3) reduces stiffness by increasing the area of ​​the flexible region, generating bending and torsional deformation, and generating passive force; The reflector (1) is located above the hinge structure (3); during the vertical translation and rotation of the reflector (1) around the axis, the reflector (1) contacts the support structure (4) and changes the axis of rotation, which changes from the hinge structure (3) to the support structure (4). The suction force provided by the electric drive structure (2) and the passive force provided by the hinge structure (3) are located on both sides of the support structure (4) and do not overlap. After the reflector (1) comes into contact with the support structure (4), the suction force, the passive force and the support structure (4) form a lever system, with the support structure (4) as the fulcrum.

2. The micromirror structure according to claim 1, characterized in that: The electric drive structure (2) of the deflection angle adjustment module includes a first electrode (21) and a second electrode (22). By applying voltage to the first electrode (21) and the second electrode (22), an electrostatic force is generated. The area where the electrostatic force is generated is opposite to the edge of the reflector (1) to be deflected. This electrostatic force is the attraction force applied by the electric drive structure (2) to the edge of the reflector (1).

3. The micromirror structure according to claim 2, characterized in that: A hinge structure (3) is suspended above the second electrode (22) via a support structure (4); the first electrode (21) is opposite to the edge of the back of the reflector (1) as the area where electrostatic force is generated; the reflector (1) is fixed to the top of the hinge structure (3).

4. The micromirror structure according to claim 1, characterized in that: The support structure (4) includes a second support column (41), the bottom end of which is fixed to the second electrode (22), and the top end is connected to the outer edge of the hinge structure (3); Alternatively, the support structure (4) includes a second support column (41) and a fulcrum (42); the bottom ends of the fulcrum (42) and the second support column (41) are fixed to the second electrode (22), the top end of the second support column (41) is connected to the outer edge of the hinge structure (3), the fulcrum (42) is not connected to the outer edge of the hinge structure (3), and the distance between the fulcrum (42) and the first support column (31) is greater than or equal to the distance between the second support column (41) and the first support column (31).

5. The micromirror structure according to claim 4, characterized in that: When the micro-mirror structure has the fulcrum (42), the back of the mirror (1) deflects to contact the fulcrum (42) during the movement. When the micro-mirror structure does not have the fulcrum (42), the back of the mirror (1) deflects to contact the second support column (41) during the movement.

6. The micromirror structure according to claim 1, characterized in that: The hinge structure (3) of the deflection angle adjustment module includes a first support column (31) and a flexible beam (32). The first support column (31) suspends the reflector (1) above the flexible beam (32). The deflection of the reflector (1) will cause the flexible beam (32) to undergo torsional and bending deformation.

7. The micromirror structure according to claim 6, characterized in that: The first support column (31) is connected between the back of the reflector (1) and the upper surface of the flexible beam (32); When the flexible beam (32) is a centrally symmetrical structure, its circumferential outer edge is fixed to the top of four second support columns (41); the first support column (31) is located at the center of the flexible beam (32); when the reflector (1) deflects, the first support column (31) will transmit the torsional moment and bending moment to the flexible beam (32), and the flexible beam (32) will generate torsional deformation and bending deformation; When the flexible beam (32) is a symmetrical structure, one side of its outer edge is fixed to the top of two second support columns (41) far away from the first electrode (21), and the other side is a cantilever structure; the first support column (31) is located at the center of the cantilever end of the flexible beam (32); when the reflector (1) deflects, the first support column (31) will transmit the torsional torque and bending torque to the flexible beam (32), and the flexible beam (32) will generate torsional deformation and bending deformation.

8. The micromirror structure according to claim 7, characterized in that: The second support column (41) and the fulcrum (42) are rectangular units or rectangular arrays.

9. The micromirror structure according to claim 8, characterized in that: The flexible beam (32) is formed by coupling a torsion beam (321) and a bending beam (322). The torsion beam (321) is connected to the first support column (31) to provide torsional moment. The bending beam (322) is coupled to the circumferential end of the torsion beam (321) and connected to the top of the support structure (4) to provide bending moment. The cooperation of the torsion beam (321) and the bending beam (322) enables the reflector (1) to generate deflection and vertical displacement simultaneously under the action of electrostatic force.

10. The micromirror structure according to claim 9, characterized in that: The flexible beam (32) reduces its stiffness by increasing the length of the torsion beam (321) and the bending beam (322), or by increasing the degree of freedom of the flexible beam (32), and generates torsional and bending deformations under the traction of the reflector (1) and the first support column (31); the structure of the flexible beam (32) is as follows: The extended curved beam (322) structure: the torsion beam (321) of the flexible beam (32) is a straight beam set in the middle, and the curved beam (322) is a wave-shaped cantilever beam coupled to both ends of the straight beam. The bending deformation and torsional deformation are increased by changing the amplitude and wavelength of the wave-shaped structure. The extended torsion beam (321) structure: the torsion beam (321) of the flexible beam (32) is an X-shaped beam set in the middle, and the bending beam (322) is four V-shaped cantilever beams coupled to the four outer ends of the X-shaped beam. The bending deformation and torsion deformation are increased by changing the beam arm length or included angle of the X-shape. The structure of the extended torsion beam (321) and the bending beam (322): The torsion beam (321) of the flexible beam (32) is formed by an X-shaped beam and four "I"-shaped beams connected together in the middle, and the bending beam (322) is formed by four n-shaped beams coupled to the "I"-shaped beam; Increased freedom structure: The flexible beam (32) is a cantilever structure, with the end of the curved beam (322) fixed to the top of two second support columns (41) away from the first electrode (21); the cantilever end of the torsion beam (321) is fixedly connected to the first support column (31), and its end is connected to the head of the curved beam (322); by changing the shape of the curved beam (322), its length is changed, thereby increasing the bending deformation and torsional deformation.

11. A method for improving the maximum deflection angle of the micromirror structure according to any one of claims 1-10, characterized in that... The specific steps are as follows: The reflector (1) is suspended above the electrically driven structure (2) via the hinge structure (3); A set voltage is applied to the electric drive structure (2) to generate electrostatic force at the edge of the side of the reflector (1) to be deflected; The reflector (1) is subjected to electrostatic force, deflects around the hinge structure (3), and generates a downward vertical displacement, while simultaneously causing the hinge structure (3) to undergo torsional and bending deformation. When the reflector (1) deflects to contact the support structure (4) on its back side, the set voltage continues to be applied to the electric drive structure (2), and the electrostatic force continues to act on the edge of the reflector (1); Under the continuous action of electrostatic force, the reflector (1) continues to deflect, and the torsional deformation of the hinge structure (3) continues to increase; the pivot changes from the hinge structure (3) to the support structure (4), and the hinge structure (3) causes the bending deformation to reverse, which is converted into an increase in the deflection angle, that is, the deflection angle is increased. By changing the shape of the hinge structure (3) to increase the deformation area, the upper limit of the deflection angle is increased.

12. The method for improving the maximum deflection angle of a micro-mirror structure according to claim 11, characterized in that: During the movement of the reflector (1), the axis of rotation changes; During the process of the reflector (1) deflecting under the action of electrostatic force, the axis of rotation is a flexible beam (32), and the reflector (1) deflects around the flexible beam (32); When the reflector (1) deflects to its back side and contacts the support structure (4), the reflector (1) deflects around the support structure (4).

13. A micromirror array, characterized in that: Includes a single micromirror structure as described in any one of claims 1-10, or several micromirror structures as described in any one of claims 1-10 arranged in an array, wherein the array arrangement is a rectangular arrangement or a diamond arrangement.

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