A shaft-coupling-free dual-axis electrostatically actuated micro-mirror and array device

Abstract

This invention provides a dual-axis electrostatically driven micromirror and array device without inter-axis coupling. The dual-axis electrostatically driven micromirror includes: a substrate; an outer frame torsion about an outer axis, and an outer axis torsion beam and anchor points fixed to the substrate; outer axis drive units arranged on both sides of the outer axis, each outer axis drive unit including two comb sets with alternating high and low interdigitation fingers; a mirror body torsion about an inner axis, and an inner axis torsion beam connecting it to the outer frame; a reflective film arranged on the upper surface of the mirror body; inner axis drive units arranged on both sides of the inner axis, each inner axis drive unit including two comb sets with alternating high and low interdigitation fingers; wires; and an insulating medium. This invention uses the mirror body, inner axis torsion beam, and inner axis drive units as follower structures of the outer frame, achieving physical isolation between the inner axis drive and the outer axis drive, and eliminating inter-axis coupling interference.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of micro-electro-mechanical system and optics, in particular to a dual-axis electrostatically actuated micro-mirror without inter-axis coupling and an array device. BACKGROUND

[0002] Since the micro-electro-mechanical system (MEMS) was proposed in the 1950s, the micro-mirror based on the MEMS technology has been a research focus and has been rapidly developed, and has been widely used in optical communication, optical switching, image display and scanning detection and other optical fields, and is one of the important foundations of the modern information society. Among them, the more famous applications include the DMD chip (Digital Micromirror Device) in the projector and the laser radar (reflecting a single probe laser to different directions) in the automatic driving system. The function of the micro-mirror is to drive the mirror to move around its torsion axis to the ideal angle, so the electrostatic driving has become the most important driving mode of the micro-mirror due to its advantages of accurate control, good driving repeatability, easy implementation and low power consumption. The principle of electrostatic driving is that by applying different voltages on a pair of positionally opposite electrostatic driving electrodes, electrostatic attraction is generated between the two electrodes, and then the two electrodes are driven to move relatively.

[0003] At present, according to the reported micro-mirrors based on electrostatic driving (whether single-axis driving or multi-axis driving), the design of the electrostatic driving electrodes is that one electrode is arranged on the substrate as a fixed electrode, and the other electrode is arranged on the movable structure (such as the mirror body) as a movable electrode. However, for multi-axis driving, if the fixed electrodes of different driving axes are all arranged on the substrate, inter-axis coupling interference will be inevitably introduced during driving. For example, when the mirror body of the dual-axis electrostatically actuated micro-mirror is twisted around the torsion axis A, the movable electrode of the torsion axis B will also move together, thereby changing the relative position of the movable electrode of the torsion axis B and the fixed electrode, and then affecting the electrostatic force between the electrostatic driving electrodes of the torsion axis B, and finally the coupling interference between the two torsion axes is generated under the mutual influence. The existence of inter-axis coupling interference directly leads to the fact that the different torsion axes of the dual-axis electrostatically actuated micro-mirror cannot work independently, and the problems in actual use can be summarized as follows: ① Introducing very complex variables in the dynamic motion process of the dual-axis electrostatically actuated micro-mirror, making the final result unpredictable, and thus reducing the control accuracy and stability of the dual-axis electrostatically actuated micro-mirror; ② Increasing the workload of the calibration of the dual-axis electrostatically actuated micro-mirror, i.e. from calibrating each torsion axis independently to calibrating the driving voltage combination of different torsion axes.

[0004] Therefore, how to solve the coupling between the two axes of the biaxial electrostatically driven micro-mirror has become one of the problems to be solved by those skilled in the art. SUMMARY

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present application is to provide a biaxial electrostatically driven micro-mirror without coupling between the two axes and an array device, which is used to solve the problem of coupling between the two axes of the biaxial electrostatically driven micro-mirror in the prior art.

[0006] To achieve the above-mentioned purpose and other related purposes, the present application provides a biaxial electrostatically driven micro-mirror without coupling between the two axes,

[0007] comprising a substrate, an outer frame twisted around an outer axis, an outer axis torsion beam, an anchor point, an outer axis driving unit, a mirror body twisted around an inner axis, a reflecting film, an inner axis torsion beam, an inner axis driving unit, a wire and an insulating medium;

[0008] The outer frame is connected to one end of the outer axis torsion beam and connected to the anchor point through the other end of the outer axis torsion beam, and is suspended and fixed on the substrate; one outer axis driving unit is arranged on each side of the outer axis, which is used to drive the outer frame to twist around the outer axis; each outer axis driving unit comprises two sets of comb teeth, which are an outer axis movable comb tooth set arranged on the outer frame and an outer axis fixed comb tooth set arranged on the substrate, and the two sets of comb teeth are distributed in high-low interdigital manner;

[0009] The reflecting film is arranged on the upper surface of the mirror body; the mirror body is connected to the outer frame through the inner axis torsion beam and is suspended and fixed on the outer frame; one inner axis driving unit is arranged on each side of the inner axis, which is used to drive the mirror body to twist around the inner axis; each inner axis driving unit comprises two sets of comb teeth, which are a mirror body comb tooth set arranged on the mirror body and an inner axis follower comb tooth set arranged on the outer frame, and the two sets of comb teeth are distributed in high-low interdigital manner; the mirror body, the inner axis torsion beam and the inner axis driving unit are all follower structures of the outer frame, which realizes physical isolation of the inner axis driving and the outer axis driving and eliminates the coupling interference between the two axes;

[0010] Except for the reflecting film, the rest of the biaxial electrostatically driven micro-mirror without coupling between the two axes is stacked by three layers of body structure layers and at least two layers of film layers;

[0011] The three layers of body structure layers are a bottom body structure layer, a middle body structure layer and a top body structure layer; the substrate is arranged in the bottom body structure layer; the mirror body, the outer frame, the inner axis torsion beam, the outer axis torsion beam and the anchor point are all arranged in the middle body structure layer or all arranged in the top body structure layer, which constitute a main continuous structure;

[0012] Two film layers are arranged between the intermediate body structure layer and the top body structure layer, which are respectively a conductive film layer and an intermediate insulating film layer; the conductive film layer is provided with the conductive wire; the intermediate insulating film layer is used to provide the insulating medium.

[0013] Optionally, the intermediate insulating film layer is located between the conductive film layer and the body structure layer where the main continuous structure is located.

[0014] Optionally, initially, the vertical projection of the mirror body comb set and the inner shaft follow-up comb set of each inner shaft driving unit on the substrate is in a finger distribution; the mirror body comb set and the inner shaft follow-up comb set of each inner shaft driving unit are respectively arranged in the intermediate body structure layer and the top body structure layer, or are respectively arranged in the top body structure layer and the intermediate body structure layer.

[0015] Optionally, initially, the vertical projection of the outer shaft movable comb set and the outer shaft fixed comb set of each outer shaft driving unit on the substrate is in a finger distribution; the outer shaft movable comb set and the outer shaft fixed comb set of each outer shaft driving unit are respectively arranged in the intermediate body structure layer and the top body structure layer, or are respectively arranged in the top body structure layer and the intermediate body structure layer.

[0016] More optionally, when the outer shaft fixed comb set is arranged in the top body structure layer, a comb support seat is arranged below the outer shaft fixed comb set, which is used to support and fix the outer shaft fixed comb set; the comb support seat is formed by a structure stack of the intermediate body structure layer, the conductive film layer and the intermediate insulating film layer.

[0017] Optionally, when the main continuous structure is arranged in the top body structure layer, an anchor point support seat is arranged below the anchor point, which is used to support and fix the anchor point; the anchor point support seat is arranged in the intermediate body structure layer.

[0018] Optionally, when the main continuous structure is arranged in the intermediate body structure layer, the driving voltage of the comb set arranged in the top body structure layer, except the outer shaft fixed comb set, is led to the surface of the anchor point by the conductive wire; when the main continuous structure is arranged in the top body structure layer, the driving voltage of the comb set arranged in the intermediate body structure layer, except the outer shaft fixed comb set, is led to the surface of the anchor point by the conductive wire.

[0019] Optionally, the driving voltages of the two inner shaft driving units and the two outer shaft driving units are independent of each other.

[0020] Optionally, the substrate is processed with a blind hole or a through hole; the vertical projection of the mirror body, the outer frame, the inner shaft torsion beam, the outer shaft torsion beam, the inner shaft follow-up comb set, the mirror body comb set and the outer shaft movable comb set on the substrate is located in the area of the blind hole or the through hole.

[0021] Optionally, the material of the bottom body structure layer is glass, silicon or metal; the material of the middle body structure layer is silicon or metal; the material of the top body structure layer is silicon or metal; the material of the conductive thin film layer is metal; the material of the middle insulating thin film layer is inorganic insulating material or organic insulating material.

[0022] Optionally, the reflective film is a metal film or a dielectric film.

[0023] Optionally, the bottom body structure layer is in direct contact with the middle body structure layer; or a thin film layer, which is a bottom insulating thin film layer, is arranged between the bottom body structure layer and the middle body structure layer to provide the insulating medium.

[0024] More optionally, the material of the bottom insulating thin film layer is inorganic insulating material or organic insulating material.

[0025] To achieve the above object and other related objects, the application further provides an array device, wherein the array elements of the array device are composed of the double-axis electrostatic driving micro mirror without inter-axis coupling.

[0026] As described above, the double-axis electrostatic driving micro mirror without inter-axis coupling and the array device of the application have the following beneficial effects:

[0027] 1. The double-axis electrostatic driving micro mirror without inter-axis coupling of the application arranges the mirror body, the inner shaft torsion beam and the inner shaft driving unit as a follow-up structure on the outer frame around the outer shaft torsion beam, realizes the physical isolation of the inner shaft driving and the outer shaft driving, and eliminates the interference of inter-axis coupling.

[0028] 2. The double-axis electrostatic driving micro mirror without inter-axis coupling of the application solves the problem of lead difficulty of the inner shaft driving unit by arranging wires on the structure surface.

[0029] 3. The double-axis electrostatic driving micro mirror without inter-axis coupling of the application is stacked by three body structure layers and at least two thin film layers, and the structure design and processing technology are relatively simple, which is conducive to batch production by using MEMS technology.

[0030] 4. The double-axis electrostatic driving micro mirror without inter-axis coupling of the application adopts the electrostatic comb driving structure with high-low interdigital distribution, which reduces the driving voltage size compared to the electrostatic flat plate driving and avoids the pull-in effect. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Fig. 1 is a perspective view of a first embodiment of a two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application.

[0032] Figure 2 Fig. 2 is an exploded view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 1

[0033] Figure 3 Fig. 3 is a top view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 1

[0034] Figure 4 Fig. 4 is a cross-sectional view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 1

[0035] Figure 5 Fig. 5 is a perspective view of a second embodiment of a two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application.

[0036] Figure 6 Fig. 6 is an exploded view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 5

[0037] Figure 7 Fig. 7 is a cross-sectional view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 5

[0038] Figure 8 Fig. 8 is a top view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 5

[0039] Figure 9 Fig. 9 is a perspective view of a third embodiment of a two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application.

[0040] Figure 10 Fig. 10 is an exploded view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 9

[0041] Figure 11 Fig. 11 is a cross-sectional view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 9

[0042] Figure 12 Fig. 12 is a top view of the two-axis electrostatically actuated micromirror without inter-axis coupling according to the present application. Figure 9

[0043] ELEMENT REFERENCE DESCRIPTION​​​​​​​​​

[0044] 10 substrate

[0045] 11 mirror body

[0046] 12 outer frame

[0047] 13 inner shaft torsion beam

[0048] 14 outer shaft torsion beam

[0049] 15 mirror body comb set

[0050] 16 inner shaft follow comb set

[0051] 17 outer shaft movable comb set

[0052] 18 outer shaft fixed comb set

[0053] 19 anchor point

[0054] 20 comb support seat

[0055] 21 anchor point support seat

[0056] 101 inner shaft

[0057] 102 outer shaft

[0058] 103 wire

[0059] 104 insulating medium

[0060] 105 reflective film

[0061] 201 bottom body structure layer

[0062] 202 middle body structure layer

[0063] 203 top body structure layer

[0064] 204 conductive film layer

[0065] 205 middle insulating film layer

[0066] 206 bottom insulating film layer DETAILED DESCRIPTION

[0067] The present application is herein described, by way of example only, with the

[0068] Please refer to Figures 1-12It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0069] Example 1

[0070] like Figure 1 As shown, this embodiment provides a dual-axis electrostatically driven micromirror without inter-axis coupling, including: a substrate 10, a mirror body 11, an outer frame 12, two inner axis torsion beams 13, two outer axis torsion beams 14, two anchor points 19, a reflective film 105, a wire 103, an insulating medium 104, two inner axis drive units (each inner axis drive unit consists of a mirror body comb set 15 and an inner axis follower comb set 16) and two outer axis drive units (each outer axis drive unit consists of an outer axis movable comb set 17, an outer axis fixed comb set 18 and a comb support 20).

[0071] like Figure 2 As shown, apart from the reflective film 105, the remaining structure of the biaxial electrostatically driven micromirror without interaxial coupling consists of three bulk structural layers and two thin film layers stacked together. The three bulk structural layers are a bottom bulk structural layer 201, an intermediate bulk structural layer 202, and a top bulk structural layer 203. The two thin film layers are arranged between the intermediate bulk structural layer 202 and the top bulk structural layer 203, namely a conductive thin film layer 204 and an intermediate insulating thin film layer 205. The intermediate insulating thin film layer 205 is arranged between the conductive thin film layer 204 and the intermediate structural layer 202. Furthermore, the intermediate structural layer 202 is in direct contact with the bottom bulk structural layer 201. The bottom bulk structural layer 201 is made of glass, the intermediate structural layer 202 and the top bulk structural layer 203 are both made of silicon, the conductive thin film layer 204 is made of gold, the intermediate insulating thin film layer 205 is made of silicon dioxide, and the reflective film 105 is a metal film.

[0072] like Figure 2As shown, the substrate 10 is disposed on the bottom body structure layer 201. The mirror body 11, the outer frame 12, the two inner shaft torsion beams 13, the two outer shaft torsion beams 14 and the two anchor points 19 are disposed on the middle body structure layer 202, forming a main continuous structure. The two mirror body comb tooth sets 15 and the two outer shaft movable comb tooth sets 17 are disposed on the middle body structure layer 202, and form an integrated structure with the main continuous structure. The two inner shaft follow-up comb tooth sets 16 and the two outer shaft fixed comb tooth sets 18 are disposed on the top body structure layer 203. Since the outer shaft fixed comb tooth set 18 is disposed on the top body structure layer 203, a comb tooth support seat 20 is arranged below it for supporting and fixing the outer shaft fixed comb tooth set 18; the comb tooth support seat 20 is composed of a part of the structure stacked on the middle body structure layer 202, the conductive film layer 204 and the middle insulating film layer 205. The conductive wire 103 is disposed on the conductive film layer 204, and the insulating medium 104 is disposed on the middle insulating film layer 205.

[0073] As shown in Figure 1 and Figure 2 , the two sides of the outer frame 12 are respectively connected with an outer shaft torsion beam 14, and are suspended and fixed on the substrate 10 through the anchor point 19 at the other end of the outer shaft torsion beam 14. The two outer shaft torsion beams 14 are used to provide the outer frame 12 with a torsion degree of freedom around the outer shaft 102. The two sides of the outer shaft 102 are respectively provided with an outer shaft driving unit for driving the outer frame 12 to twist around the outer shaft 102. The two outer shaft fixed comb tooth sets 18 are fixed on the substrate 10.

[0074] As shown in Figure 1 and Figure 2 , the reflective film 105 is arranged on the upper surface of the mirror body 11. The two sides of the mirror body 11 are respectively connected with an inner shaft torsion beam 13, and are suspended and fixed on the outer frame 12 through the other end of the inner shaft torsion beam 13. The two inner shaft torsion beams 13 are used to provide the mirror body 11 with a torsion degree of freedom around the inner shaft 101. The two sides of the inner shaft 101 are respectively provided with an inner shaft driving unit for driving the mirror body 11 to twist around the inner shaft 101. The two inner shaft follow-up comb tooth sets 16 are fixed on the outer frame 12. Since the mirror body 11, the inner shaft torsion beam 13 and the inner shaft driving unit are all arranged on the outer frame 12, the mirror body 11 can not only independently twist around the inner shaft 101, but also twist around the outer shaft 102 following the outer frame 12, realizing physical isolation of the inner shaft driving and the outer shaft driving, and eliminating the coupling interference between the shafts. In addition, the inner shaft 101 and the outer shaft 102 intersect.

[0075] As shown in Figure 1 , Figure 2 and Figure 3As shown in the figure, the conducting wire 103 is arranged on the upper surface of the outer frame 12, the two outer shaft torsion beams 14 and the two anchor points 19 through the insulating medium 104, and the driving voltage of the two inner shaft driven comb sets 16 is introduced to the upper surface of the anchor points 19, so as to avoid the flying wire on the movable structure.

[0076] As shown in the figure, Figure 1 and Figure 2 Since the two inner shaft driven comb sets 16 and the two outer shaft fixed comb sets 18 are both structurally independent and in contact with the insulating medium 104, the four are insulated from each other, so as to ensure that the driving voltages of the two inner shaft driving units and the two outer shaft driving units are independent from each other.

[0077] As shown in the figure, Figure 3 In the initial state, the vertical projection of the mirror comb set 15 and the inner shaft driven comb set 16 of each inner shaft driving unit on the substrate 10 is in a finger distribution. Therefore, when the voltage is applied to the mirror comb set 15 and the inner shaft driven comb set 16 in different body structure layers, the electrostatic force perpendicular to the upper surface of the substrate 10 is generated between the two, so as to drive the mirror body 11 to twist around the inner shaft 101.

[0078] As shown in the figure, Figure 3 In the initial state, the vertical projection of the outer shaft movable comb set 17 and the outer shaft fixed comb set 18 of each outer shaft driving unit on the substrate 10 is in a finger distribution. Therefore, when the voltage is applied to the outer shaft movable comb set 17 and the outer shaft fixed comb set 18 in different body structure layers, the electrostatic force perpendicular to the upper surface of the substrate 10 is generated between the two, so as to drive the outer frame 12 to twist around the outer shaft 102.

[0079] As shown in the figure, Figure 4 The blind hole is processed on the substrate 10 to provide the movable structure with a torsion activity space. As shown in the figures, Figure 1 , Figure 3 and Figure 4 The vertical projection area of the mirror body 11, the outer frame 12, the two inner shaft torsion beams 13, the two outer shaft torsion beams 14, the two mirror comb sets 15, the two inner shaft driven comb sets 16 and the two outer shaft movable comb sets 18 on the substrate 10 is in the blind hole area.

[0080] The shaft-coupling-free double-shaft electrostatic driving micro mirror of the embodiment realizes the physical isolation of the inner shaft driving and the outer shaft driving, eliminates the interference of the shaft coupling, solves the problem of the wire introduction of the inner shaft driving unit, reduces the driving voltage size, and is more conducive to the batch production by using the MEMS process.

[0081] Embodiment Two

[0082] As shown in the figure, Figure 5As shown, this embodiment provides a dual-axis electrostatically driven micromirror without inter-axis coupling, including: a substrate 10, a mirror body 11, an outer frame 12, two inner axis torsion beams 13, two outer axis torsion beams 14, two anchor points 19, two anchor point support seats 21, a reflective film 105, a wire 103, an insulating medium 104, two inner axis drive units (each inner axis drive unit consists of a mirror body comb set 15 and an inner axis follower comb set 16) and two outer axis drive units (each outer axis drive unit consists of an outer axis movable comb set 17 and an outer axis fixed comb set 18).

[0083] like Figure 6 As shown, except for the reflective film 105, the remaining structure of the biaxial electrostatically driven micromirror without interaxial coupling consists of three bulk structure layers and three thin film layers stacked together. The three bulk structure layers are a bottom bulk structure layer 201, an intermediate bulk structure layer 202, and a top bulk structure layer 203. Two thin film layers are arranged between the intermediate bulk structure layer 202 and the top bulk structure layer 203, namely a conductive thin film layer 204 and an intermediate insulating thin film layer 205. The intermediate insulating thin film layer 205 is arranged between the conductive thin film layer 204 and the top bulk structure layer 203. A thin film layer, the bottom insulating thin film layer 206, is arranged between the intermediate bulk structure layer 202 and the bottom bulk structure layer 201. The bottom bulk structure layer 201, the intermediate bulk structure layer 202, and the top bulk structure layer 203 are all made of silicon, the conductive thin film layer 204 is made of gold, the intermediate insulating thin film layer 205 and the bottom insulating thin film layer 206 are made of homogeneous silicon dioxide, and the reflective film 105 is a dielectric film.

[0084] like Figure 6 As shown, substrate 10 is disposed on bottom body structure layer 201. Reflector body 11, outer frame 12, two inner shaft torsion beams 13, two outer shaft torsion beams 14, and two anchor points 19 are all disposed on top body structure layer 203, forming a continuous main structure. Since anchor points 19 are disposed on top body structure layer 203, an anchor point support 21 is arranged below them to support and fix anchor points 19; anchor point support 21 is disposed on intermediate body structure layer 202. Two mirror comb sets 15 and two outer shaft movable comb sets 17 are all disposed on top body structure layer 203, forming an integrated structure with the continuous main structure. Two inner shaft follower comb sets 16 and two outer shaft fixed comb sets 18 are all disposed on intermediate body structure layer 202. Conductor 103 is disposed on conductive thin film layer 204, and insulating medium 104 is disposed on intermediate insulating thin film layer 205 and bottom insulating thin film layer 206.

[0085] like Figure 5 and Figure 6As shown, an outer frame 12 is connected to an outer shaft torsion beam 14 on each side, and is suspended and fixed to the substrate 10 via anchor points 19 at the other ends of the outer shaft torsion beams 14. The two outer shaft torsion beams 14 provide the outer frame 12 with torsional freedom around the outer shaft 102. An outer shaft drive unit is provided on each side of the outer shaft 102 to drive the outer frame 12 to torsion around the outer shaft 102. Both outer shaft fixed comb sets 18 are fixed to the substrate 10.

[0086] like Figure 5 and Figure 6 As shown, a reflective film 105 is arranged on the upper surface of the reflector body 11. An inner axis torsion beam 13 is connected to each side of the reflector body 11, and the other end of the inner axis torsion beam 13 is connected to the outer frame 12, thus suspending and fixing it to the outer frame 12. The two inner axis torsion beams 13 provide the reflector body 11 with torsional freedom around the inner axis 101. An inner axis drive unit is provided on each side of the inner axis 101 to drive the reflector body 11 to rotate around the inner axis 101. Both inner axis follower comb sets 16 are fixed to the outer frame 12. Since the reflector body 11, the inner axis torsion beams 13, and the inner axis drive units are all follower structures arranged on the outer frame 12, the reflector body 11 can rotate independently around the inner axis 101 and also rotate with the outer frame 12 around the outer axis 102, achieving physical isolation between the inner axis drive and the outer axis drive, and eliminating inter-axis coupling interference. In addition, the inner shaft 101 and the outer shaft 102 intersect.

[0087] like Figure 5 , Figure 6 and Figure 7 As shown, the conductor 103 is arranged on the lower surface of the outer frame 12, the two outer shaft torsion beams 14 and the two anchor points 19 through the insulating medium 104, so as to lead the driving voltage of the two inner shaft follower comb teeth 16 to the lower surface of the anchor points 19, thereby avoiding the need for flying wires on the movable structure.

[0088] like Figure 5 and Figure 6 As shown, since the two inner shaft follower comb sets 16 and the two outer shaft fixed comb sets 18 are all structurally independent and are in contact with the insulating medium 104, the four are mutually insulated, thus ensuring that the driving voltages of the two inner shaft drive units and the two outer shaft drive units are independent of each other.

[0089] like Figure 8 As shown, initially, the vertical projections of the mirror comb set 15 and the inner axis follower comb set 16 of each inner axis drive unit onto the substrate 10 are interdigitated. Therefore, when a voltage is applied to the mirror comb set 15 and the inner axis follower comb set 16 located in different bulk structure layers, an electrostatic force perpendicular to the upper surface of the substrate 10 is generated between them, thereby driving the reflective mirror 11 to twist around the inner axis 101.

[0090] As shown in Figure 8 , initially, the vertical projection of the outer shaft movable comb set 17 and the outer shaft fixed comb set 18 of each outer shaft driving unit on the substrate 10 is in a finger interlaced distribution. Therefore, when a voltage is applied to the outer shaft movable comb set 17 and the outer shaft fixed comb set 18 on different body structure layers, an electrostatic force perpendicular to the upper surface of the substrate 10 is generated between the two, thereby driving the outer frame 12 to twist around the outer shaft 102.

[0091] As shown in Figure 7 , blind holes are processed on the substrate 10 to provide a twisting activity space for the movable structure. As shown in Figure 7 and Figure 8 , the vertical projection of the mirror body 11, the outer frame 12, the two inner shaft torsion beams 13, the two outer shaft torsion beams 14, the two mirror body comb sets 15, the two inner shaft following comb sets 16, and the two outer shaft movable comb sets 18 on the substrate 10 is located in the blind hole area.

[0092] The shaft-coupling-free dual-axis electrostatic driving micro mirror of the embodiment realizes physical isolation of the inner shaft driving and the outer shaft driving, eliminates the interference of shaft coupling, solves the problem of lead difficulty of the inner shaft driving unit, reduces the driving voltage size, and is more conducive to batch production using the MEMS process.

[0093] Embodiment Three

[0094] As shown in Figure 9 , the embodiment provides a shaft-coupling-free dual-axis electrostatic driving micro mirror, which comprises a substrate 10, a mirror body 11, an outer frame 12, two inner shaft torsion beams 13, two outer shaft torsion beams 14, two anchor points 19, a reflective film 105, a wire 103, an insulating medium 104, two inner shaft driving units (each inner shaft driving unit is composed of a mirror body comb set 15 and an inner shaft following comb set 16), and two outer shaft driving units (each outer shaft driving unit is composed of an outer shaft movable comb set 17, an outer shaft fixed comb set 18, and a comb support seat 20).

[0095] As shown in Figure 10As shown, the rest of the structure of the biaxial electrostatically actuated micro-mirror without inter-axial coupling, except the reflecting film 105, is stacked by three bulk structure layers and two thin film layers. The three bulk structure layers are the bottom bulk structure layer 201, the middle bulk structure layer 202 and the top bulk structure layer 203. The two thin film layers are arranged between the middle bulk structure layer 202 and the top bulk structure layer 203, which are the conductive thin film layer 204 and the middle insulating thin film layer 205. Among them, the middle insulating thin film layer 205 is arranged between the conductive thin film layer 204 and the middle bulk structure layer 202. In addition, the middle bulk structure layer 202 is in direct contact with the bottom bulk structure layer 201. Among them, the material of the bottom bulk structure layer 201 is glass, the materials of the middle bulk structure layer 202 and the top bulk structure layer 203 are silicon, the material of the conductive thin film layer 204 is gold, the material of the middle insulating thin film layer 205 is silicon dioxide, and the reflecting film 105 is a metal film.

[0096] As shown in Figure 10 , the substrate 10 is arranged on the bottom bulk structure layer 201. The mirror body 11, the outer frame 12, the two inner shaft torsion beams 13, the two outer shaft torsion beams 14 and the two anchor points 19 are arranged on the middle bulk structure layer 202, forming a main continuous structure. The two inner shaft slave comb sets 16 and the two outer shaft movable comb sets 17 are arranged on the middle bulk structure layer 202, and form an integrated structure with the main continuous structure. The two mirror body comb sets 15 and the two outer shaft fixed comb sets 18 are arranged on the top bulk structure layer 203. Since the outer shaft fixed comb set 18 is arranged on the top bulk structure layer 203, a comb support seat 20 is arranged below it for supporting and fixing the outer shaft fixed comb set 18; the comb support seat 20 is composed of the structure stacked and combined on the middle bulk structure layer 202, the conductive thin film layer 204 and the middle insulating thin film layer 205. The conductive thin film layer 204 is provided with a wire 103, and the middle insulating thin film layer 205 is provided with an insulating medium 104.

[0097] As shown in Figure 9 and Figure 10 , the two sides of the outer frame 12 are respectively connected with an outer shaft torsion beam 14, and the outer shaft torsion beam 14 is connected with the anchor point 19, which is suspended and fixed on the substrate 10. The two outer shaft torsion beams 14 are used to provide the outer frame 12 with a torsion degree of freedom around the outer shaft 102. The two sides of the outer shaft 102 are respectively provided with an outer shaft driving unit for driving the outer frame 12 to twist around the outer shaft 102. Among them, the two outer shaft fixed comb sets 18 are fixed on the substrate 10.

[0098] As shown in Figure 9 and Figure 10As shown, a reflective film 105 is arranged on the upper surface of the reflector body 11. An inner axis torsion beam 13 is connected to each side of the reflector body 11, and the other end of the inner axis torsion beam 13 is connected to the outer frame 12, thus suspending and fixing it to the outer frame 12. The two inner axis torsion beams 13 provide the reflector body 11 with torsional freedom around the inner axis 101. An inner axis drive unit is provided on each side of the inner axis 101 to drive the reflector body 11 to rotate around the inner axis 101. Both mirror comb sets 15 are fixed to the reflector body 11. Since the reflector body 11, the inner axis torsion beams 13, and the inner axis drive units are all follower structures arranged on the outer frame 12, the reflector body 11 can rotate independently around the inner axis 101 and also rotate with the outer frame 12 around the outer axis 102, achieving physical isolation between the inner axis drive and the outer axis drive, and eliminating inter-axis coupling interference. In addition, the inner shaft 101 and the outer shaft 102 intersect.

[0099] like Figure 9 , Figure 10 and Figure 11 As shown, the conductor 103 is arranged on the upper surface of the reflector body 11, the two inner shaft torsion beams 13, the outer frame 12, the two outer shaft torsion beams 14 and the two anchor points 19 through the insulating medium 104, so as to lead the driving voltage of the two mirror comb set 15 to the upper surface of the anchor point 19, thereby avoiding the need for flying wires on the movable structure.

[0100] like Figure 9 and Figure 10 As shown, since the two mirror comb sets 15 and the two outer shaft fixed comb sets 18 are all structurally independent and are in contact with the insulating medium 104, the four are mutually insulated, thus ensuring that the driving voltages of the two inner shaft drive units and the two outer shaft drive units are independent of each other.

[0101] like Figure 11 As shown, initially, the vertical projections of the mirror comb set 15 and the inner axis follower comb set 16 of each inner axis drive unit onto the substrate 10 are interdigitated. Therefore, when a voltage is applied to the mirror comb set 15 and the inner axis follower comb set 16 located in different bulk structure layers, an electrostatic force perpendicular to the upper surface of the substrate 10 is generated between them, thereby driving the reflective mirror 11 to twist around the inner axis 101.

[0102] like Figure 11 As shown, initially, the vertical projections of the movable comb set 17 and the fixed comb set 18 of each outer shaft drive unit onto the substrate 10 are interdigitated. Therefore, when a voltage is applied to the movable comb set 17 and the fixed comb set 18 located in different bulk structure layers, an electrostatic force perpendicular to the upper surface of the substrate 10 is generated between them, thereby driving the outer frame 12 to twist around the outer shaft 102.

[0103] As shown in Figure 12 A through hole is formed on the substrate 10 to provide a torsional moving space for the movable structure. Figure 11 As shown in Figure 12 The vertical projections of the mirror body 11, the outer frame 12, the two inner shaft torsional beams 13, the two outer shaft torsional beams 14, the two mirror body comb sets 15, the two inner shaft follower comb sets 16 and the two outer shaft movable comb sets 18 on the substrate 10 are located in the through hole region.

[0104] The double-axis electrostatic driving micro mirror without inter-axis coupling in the embodiment realizes the physical isolation of the inner shaft driving and the outer shaft driving, eliminates the interference of inter-axis coupling, solves the problem of lead difficulty of the inner shaft driving unit, reduces the driving voltage size, and is more conducive to the batch production by using the MEMS process.

[0105] Embodiment Four

[0106] The embodiment provides an array device, and an array element of the array device is composed of the double-axis electrostatic driving micro mirror without inter-axis coupling described in the embodiment one, the embodiment two or the embodiment three.

[0107] In summary, the present application provides a kind of double shaft electrostatic drive micro mirror without inter-axis coupling and array device, the double shaft electrostatic drive micro mirror without inter-axis coupling includes substrate, outer frame that is twisted around outer shaft, outer shaft torsion beam, anchor point, outer shaft drive unit, mirror body that is twisted around inner shaft, reflecting film, inner shaft torsion beam, inner shaft drive unit, wire and insulating medium;The outer frame is connected with one end of the outer shaft torsion beam, and the other end of the outer shaft torsion beam is connected with the anchor point, and is suspended and fixed on the substrate;Two sides of the outer shaft are respectively arranged with one outer shaft drive unit, for driving the outer frame to be twisted around the outer shaft;Each outer shaft drive unit includes two comb teeth sets, which are outer shaft movable comb teeth set arranged on the outer frame and outer shaft fixed comb teeth set arranged on the substrate, and are distributed with high-low interdigital;The reflecting film is arranged on the upper surface of the mirror body;The mirror body is connected with the outer frame through the inner shaft torsion beam, and is suspended and fixed on the outer frame;Two sides of the inner shaft are respectively arranged with one inner shaft drive unit, for driving the mirror body to be twisted around the inner shaft;Each inner shaft drive unit includes two comb teeth sets, which are mirror body comb teeth set arranged on the mirror body and inner shaft follow-up comb teeth set arranged on the outer frame, and are distributed with high-low interdigital;The mirror body, the inner shaft torsion beam and the inner shaft drive unit are follow-up structures of the outer frame, realize the physical isolation of inner shaft drive and outer shaft drive, eliminate inter-axis coupling interference;Except the reflecting film, the rest of the double shaft electrostatic drive micro mirror without inter-axis coupling is stacked by three body structure layers and at least two film layers;Three body structure layers are bottom body structure layer, middle body structure layer and top body structure layer respectively;The substrate is arranged in the bottom body structure layer;The mirror body, the outer frame, the inner shaft torsion beam, the outer shaft torsion beam and the anchor point are arranged in the middle body structure layer or are arranged in the top body structure layer, and form main body continuous structure;Two film layers are arranged between the middle body structure layer and the top body structure layer, which are conductive film layer and middle insulating film layer respectively;The wire is arranged in the conductive film layer;The middle insulating film layer is used to provide the insulating medium.The double shaft electrostatic drive micro mirror without inter-axis coupling of the present application arranges the mirror body, the inner shaft torsion beam and the inner shaft drive unit as follow-up structures on the outer frame twisted around the outer shaft, realizes the physical isolation of inner shaft drive and outer shaft drive, and eliminates the interference of inter-axis coupling.Therefore, the present application effectively overcomes the shortcomings in the prior art and has high industrial utilization value.

[0108] The above embodiments are only illustrative of the principles of the present application and its efficacy, and are not intended to limit the present application. Any modification or change made by any person skilled in the art without departing from the spirit and scope of the present application shall be covered by the claims of the present application.

Claims

1. An interaxis coupling free biaxial electrostatically actuated micro-mirror, characterized in that, Comprise: Substrate, outer frame twisted around outer shaft, outer shaft torsion beam, anchor point, outer shaft drive unit, mirror body twisted around inner shaft, reflective film, inner shaft torsion beam, inner shaft drive unit, wire and insulating medium; The outer frame is connected to one end of the outer shaft torsion beam, and is suspended and fixed on the substrate through the other end of the outer shaft torsion beam; The two sides of the outer shaft are respectively arranged with one outer shaft drive unit for driving the outer frame to twist around the outer shaft; Each outer shaft drive unit comprises two comb sets, namely outer shaft movable comb set arranged on the outer frame and outer shaft fixed comb set arranged on the substrate, which are distributed in high-low interdigital manner; The reflective film is arranged on the upper surface of the mirror body; The mirror body is connected to the outer frame through the inner shaft torsion beam and is suspended and fixed on the outer frame; The two sides of the inner shaft are respectively arranged with one inner shaft drive unit for driving the mirror body to twist around the inner shaft; Each inner shaft drive unit comprises two comb sets, namely mirror body comb set arranged on the mirror body and inner shaft follow-up comb set arranged on the outer frame, which are distributed in high-low interdigital manner; The mirror body, the inner shaft torsion beam and the inner shaft drive unit are all follow-up structures of the outer frame, realizing physical isolation of inner shaft driving and outer shaft driving and eliminating inter-axis coupling interference; Except the reflective film, the rest of the double-axis electrostatic driving micro-mirror without inter-axis coupling is stacked by three body structure layers and at least two film layers; The three body structure layers are bottom body structure layer, middle body structure layer and top body structure layer respectively; The substrate is arranged on the bottom body structure layer; The mirror body, the outer frame, the inner shaft torsion beam, the outer shaft torsion beam and the anchor point are all arranged on the middle body structure layer or all arranged on the top body structure layer, forming a main continuous structure; Two film layers are arranged between the middle body structure layer and the top body structure layer, which are conductive film layer and middle insulating film layer respectively; The wire is arranged on the conductive film layer; The middle insulating film layer is used to provide the insulating medium; The mirror body comb set and the inner shaft follow-up comb set of each inner shaft drive unit are arranged on the middle body structure layer and the top body structure layer respectively, or are arranged on the top body structure layer and the middle body structure layer respectively; The outer shaft movable comb set and the outer shaft fixed comb set of each outer shaft drive unit are arranged on the middle body structure layer and the top body structure layer respectively, or are arranged on the top body structure layer and the middle body structure layer respectively; The middle insulating film layer is located between the conductive film layer and the body structure layer where the main continuous structure is located; The material of the bottom body structure layer is glass, silicon or metal; The material of the middle body structure layer is silicon or metal; The material of the top body structure layer is silicon or metal; The material of the conductive film layer is metal.

2. The double-axis electrostatic driving micro-mirror without inter-axis coupling according to claim 1, wherein: The vertical projection of the mirror body comb set and the inner shaft follower comb set of each inner shaft driving unit on the substrate is in a finger distribution initially.

3. The inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to claim 1, characterized in that: The vertical projection of the outer shaft movable comb set and the outer shaft fixed comb set of each outer shaft driving unit on the substrate is in a finger distribution initially.

4. The inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to claim 3, characterized in that: When the outer shaft fixed comb set is arranged on the top body structure layer, a comb support seat is arranged below the outer shaft fixed comb set for supporting and fixing the outer shaft fixed comb set; The comb support seat is formed by a structure stack of the middle body structure layer, the conductive film layer and the middle insulating film layer.

5. The inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to claim 1, characterized in that: When the main body continuous structure is arranged on the top body structure layer, an anchor support seat is arranged below the anchor for supporting and fixing the anchor; the anchor support seat is arranged on the middle body structure layer.

6. The inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to claim 1, characterized in that: When the main body continuous structure is arranged on the middle body structure layer, the driving voltage of the comb set arranged on the top body structure layer, except the outer shaft fixed comb set, is led to the surface of the anchor by the conductive wire; When the main body continuous structure is arranged on the top body structure layer, the driving voltage of the comb set arranged on the middle body structure layer, except the outer shaft fixed comb set, is led to the surface of the anchor by the conductive wire.

7. The interaxis coupling free biaxial electrostatically actuated micromirror according to claim 1, characterized in that: The driving voltages of the two inner shaft driving units and the two outer shaft driving units are independent of each other.

8. The inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to claim 1, characterized in that: Blind holes or through holes are processed on the substrate; The vertical projection of the mirror body, the outer frame, the inner shaft torsion beam, the outer shaft torsion beam, the inner shaft follower comb set, the mirror body comb set and the outer shaft movable comb set on the substrate is located in the area of the blind holes or the through holes.

9. The interaxis coupling free biaxial electrostatically actuated micromirror according to claim 1, characterized in that: The material of the middle insulating film layer is inorganic insulating material or organic insulating material.

10. The interaxis coupling free biaxial electrostatically actuated micromirror according to claim 1, characterized in that: The reflecting film is metal film or dielectric film.

11. The inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to claim 1, characterized in that: The bottom body structure layer is in direct contact with the middle body structure layer; or a film layer, which is a bottom insulating film layer, is arranged between the bottom body structure layer and the middle body structure layer for providing the insulating medium.

12. The inter-axis coupling free biaxial electrostatically actuated micromirror according to claim 11, characterized in that: The material of the bottom insulating film layer is inorganic insulating material or organic insulating material.

13. An array device, characterized by: The array element of the array device is composed of the inter-axis coupling-free dual-axis electrostatically actuated micro-mirror according to any one of claims 1 to 12.

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