CN109581653B - MEMS driver based on protruding comb teeth and working method thereof - Google Patents
MEMS driver based on protruding comb teeth and working method thereof Download PDFInfo
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- CN109581653B CN109581653B CN201910070805.6A CN201910070805A CN109581653B CN 109581653 B CN109581653 B CN 109581653B CN 201910070805 A CN201910070805 A CN 201910070805A CN 109581653 B CN109581653 B CN 109581653B
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- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
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- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
- G02B26/0841—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD the reflecting element being moved or deformed by electrostatic means
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Abstract
The invention relates to an MEMS (micro electro mechanical system) driver based on protruding comb teeth and a working method thereof, belonging to the field of micro electro mechanical systems. Compared with the prior art, the invention adopts the protruding comb tooth structure, the front and back widths of the comb teeth are different, after voltage is applied, the comb teeth with narrower front ends are inserted into the space slightly wider than the comb teeth, and the space between the comb teeth is smaller; the front end and the rear end of the comb teeth form different electrostatic drivers respectively, namely more pairs of comb teeth can be arranged for driving in the same structural length, the comb teeth are all helpful for reducing voltage, the comb teeth can be applied to an external cavity tunable laser, and the side surface of the comb teeth can be installed or manufactured into a grating or a plane mirror to realize mode-hopping-free tuning of the laser.
Description
Technical Field
The invention relates to an MEMS device structure, in particular to an MEMS driver based on protruding comb teeth and a working method thereof, and belongs to the technical field of micro electro mechanical systems.
Background
Since the advent of lasers, tunable light sources have received significant attention. Compared with other lasers, the tunable laser has the outstanding advantages of compact structure, large tuning range, narrow line width, large-scale production, low price and the like, and has shown more and more extensive application prospects in the scientific field. It has many applications in spectral analysis, laser ranging, industrial field process detection, atmospheric environmental pollution detection, medical diagnosis, optical communication, radar, etc. Currently available tunable lasers are roughly classified into distributed bragg reflection type lasers, distributed feedback type laser arrays, highly integrated distributed feedback type laser arrays, and highly integrated MEMS mirror-based external cavity tunable lasers, etc. The highly integrated tunable external cavity laser based on the MEMS rotating mirror has unique advantages in the aspects of small volume, narrow line width and the like.
MEMS (micro electro mechanical systems) is a 21 st century leading technology based on micro/nano technology, which refers to a technology for designing, processing, manufacturing, measuring and controlling micro/nano materials. The micro-system can integrate mechanical components, optical systems, driving parts and electric control systems into a whole unit. Such electro-mechanical systems are capable of not only collecting, processing and transmitting information or instructions, but also taking actions autonomously according to the information acquired or according to external instructions. It uses the combined manufacturing process of microelectronic technique and micro-processing technique (including silicon body micro-processing, silicon surface micro-processing, LIGA and wafer bonding etc) to make various sensors, actuators, drivers and microsystems with excellent performance, low cost and miniaturization. The MEMS rotating mirror is applied to an external cavity tunable laser, and is an important component of MEMS technology. Most MEMS mirrors use the top silicon surface of the wafer as the reflective surface, and the MEMS mirror rotates around a point within the silicon surface. However, many applications such as external cavity tunable lasers, but also optical tomography and optical filters require that the turning mirror be translated in-plane or that the turning mirror be moved around an outer virtual axis point, the use of a top silicon surface as a mirror is not suitable for the above applications, and a vertical MEMS mirror with in-plane movement may suffice for the relevant applications.
In 2003, an external cavity tunable laser proposed by Ionon corporation utilizes a design that a vertical MEMS mirror with in-plane movement rotates around a virtual axis point, so that large-range mode-hopping-free tuning, narrow line width and high tuning speed can be realized, but in order to meet the requirement of large-range mode-hopping-free tuning, the design needs high voltage to drive a MEMS turning mirror, which puts high requirements on an external driving circuit, limits the application of the laser, and is not favorable for long-term use of the laser.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an MEMS driver based on protruding comb teeth and a working method thereof, which reduce the driving voltage of a vertical MEMS mirror with in-plane movement. Compare in general conventional driver, this drive has adopted protruding broach structure, and this broach front and back width is inequality, and after the applied voltage, the broach that the front end is narrower will insert in the interval that slightly is wider than the broach to it is littleer to make the interval between the broach than the broach of making between the broach, helps when the driver produces the same displacement, and driving voltage reduces. The front end and the rear end of the comb teeth form different electrostatic drivers respectively, namely more pairs of comb teeth can be arranged for driving in the same structural length, and the reduction of driving voltage is facilitated. According to the embodiment of the invention, a scheme of rotating around an imaginary axis point at two sides based on four pairs of combs, two elastic beams and a fixed anchor point is adopted, so that large-angle rotation and low-voltage driving can be realized.
Interpretation of terms:
truss, also known as truss, is a supporting beam structure formed by connecting rods by welding, riveting or bolts.
The invention adopts the following technical scheme:
the invention provides an MEMS driver based on protruding comb teeth, which comprises a movable part, a fixed comb, fixed anchor points and a substrate layer, wherein the fixed comb and the fixed anchor points are fixed on the substrate layer;
the movable part comprises a radial truss, an arc truss, a movable comb and an elastic beam, the arc truss is arranged at an arc position taking a virtual axis point as a circle, the radial truss is arranged along the radius direction, the movable comb comprises a plurality of movable comb teeth, the movable comb is formed by connecting the plurality of movable comb teeth through the radial truss, the radial truss is connected with the arc truss at an intersection point, the fixed end of the elastic beam is connected with the fixed anchor point, the free end of the elastic beam is connected with the arc truss, the elastic beam is arranged along the radius direction taking the virtual axis point as the circle, in the invention, the movable part is only connected with the fixed anchor point through the elastic beam, and other parts are movable;
the fixed comb comprises fixed comb teeth and a connecting beam, one side of each fixed comb tooth is connected through the connecting beam, and the fixed comb and the movable comb are distributed in a crossed mode in pairs;
the movable comb teeth and the fixed comb teeth are protruding comb teeth, the protruding comb teeth comprise front-end narrow comb teeth and rear-end wide comb teeth which are connected in a front-back mode, the lengths of the front-end narrow comb teeth and the rear-end wide comb teeth are arcs with virtual axis points as circle centers, and the protruding comb teeth are located on arc positions corresponding to the radii. The center of the connecting side of the front narrow comb teeth and the center of the connecting side of the rear wide comb teeth are connected to form protruding comb teeth which can be used as movable comb teeth or fixed comb teeth. When voltage is applied, the movable part rotates around a virtual axis point, and the rotation power is provided by electrostatic force generated by voltage difference between the movable comb teeth and the fixed comb teeth.
Preferably, the corresponding degrees of the central angles of all the front-end narrow comb teeth are the same and are 1.5-3 degrees, the widths of all the front-end narrow comb teeth are equal to the central angles multiplied by the corresponding radiuses, and the widths of the front-end narrow comb teeth are 5-8 microns;
preferably, the central angles corresponding to all the rear-end wide comb teeth are the same and are 2-3.5 degrees, the width of the rear-end wide comb teeth is equal to the radius corresponding to the central angle, and the width is 13-16 um.
Preferably, the distance between two adjacent rear end wide comb teeth of the movable comb teeth and the distance between two adjacent rear end wide comb teeth of the fixed comb teeth are both 9-18 um.
Preferably, when no voltage is applied, the distance between the front end narrow comb teeth of the movable comb teeth and the front end narrow comb teeth of the fixed comb teeth is 6um to 8 um. After voltage is applied, namely after the narrow comb teeth at the front end are inserted into the wide comb teeth at the rear end, the distance is preferably 2um, and the process requirement is low.
Preferably, the radius of the outermost arc of the movable comb teeth is 3540um, the radius of the outermost arc of the arc truss is 3600um, the corresponding central angle of the arc truss is 39-45 degrees, and the widths of the arc truss and the radial truss are both 30-32 um;
the MEMS driver comprises a plurality of pairs of fixed combs and movable combs, preferably 4-8 pairs, and the fixed combs and the movable combs are symmetrically distributed in the arc-direction truss and symmetrically distributed around the elastic beam; the number of pairs of comb teeth in each pair of the fixed comb and the movable comb is 45-50.
Further preferably, the number of the elastic beams is half of the number of pairs of the fixed combs and the movable combs, and two pairs of comb teeth close to the elastic beams are symmetrically distributed around the elastic beams;
preferably, the length of elastic beam is 850 ~ 1000um, and the width is 7 ~ 9um, and a plurality of elastic beams are in arc is to truss in the symmetric distribution.
Further preferably, the movable part, the fixed comb, the fixed anchor points and the substrate layer are made of silicon, and the surfaces of the fixed anchor points and the connecting beam are plated with gold and used as electrodes to ground the movable comb teeth and supply power to the fixed comb teeth.
Further preferably, the thickness of the movable part is 50-70 um.
Preferably, the movable comb, the fixed anchor point and the basal layer are grounded to control the voltage of the fixed comb, the narrow comb tooth at the front end of the movable comb tooth applying voltage corresponding to the fixed comb is inserted into a gap between the wide comb teeth at the rear end of two adjacent fixed comb teeth, the arc side edges of the narrow comb tooth at the front end and the wide comb tooth at the rear end are two electrodes, a tangential capacitance effect and a radial capacitance effect are formed between the two electrodes, a tangential electrostatic driving force is generated due to the tangential capacitance effect, the tangential electrostatic force drives the free end of the elastic beam to bend, so that the movable part rotates around a virtual axis point, wherein the formula of the tangential electrostatic force is as follows
In the formula (1), N is the number of comb teeth on a comb, ε is a dielectric constant, V is a voltage difference between movable comb teeth and fixed comb teeth, H is a thickness H1 of the movable portion, and g is an interval H2 between arc sides of front-end narrow comb teeth and rear-end wide comb teeth.
According to the formula (1), when the front end narrow comb tooth is to be inserted into the gap between the rear end wide comb teeth of the adjacent two fixed comb teeth, the interval between the front end narrow comb teeth of the fixed comb tooth and the movable comb tooth becomes the interval between the front end narrow comb tooth of the fixed comb tooth (or the movable comb tooth) and the rear end wide comb tooth of the movable comb tooth (or the fixed comb tooth), and the tangential electrostatic force increases, so that the drive displacement increases.
On the other hand, the invention provides an operating method of the MEMS driver based on protruding comb teeth, where the number of pairs of the fixed comb and the movable comb is M, the number of the elastic beams is M/2, and the number of the combs in the MEMS driver from left to right is: the comb comprises a first movable comb, a first fixed comb, a second movable comb, a third fixed comb, a fourth movable comb, …, an Mth fixed comb and an Mth movable comb, wherein M is an even number which is more than or equal to 4;
the movable comb, the fixed anchor points and the basal layer are all grounded, the first fixed comb, the third fixed comb, … and the M-1 fixed comb are pressurized to generate tangential electrostatic force in the rightward direction, the elastic beam is driven to bend by the tangential electrostatic force in the rightward direction and rotates around the virtual axis point to the right side, and at the moment, the first movable comb and the first fixed comb, the third movable comb and the third fixed comb, …, the M-1 movable comb and the M-1 fixed comb are all close to each other, the second fixed comb and the second movable comb, the fourth fixed comb and the fourth movable comb, and the M fixed comb and the M movable comb are all far away from each other.
In another aspect, the present invention further provides a working method of the MEMS actuator based on protruding comb teeth, where the number of pairs of the fixed comb and the movable comb is M, the number of the elastic beams is M/2, and the number of the combs in the MEMS actuator from left to right is: the comb comprises a first movable comb, a first fixed comb, a second movable comb, a third fixed comb, a fourth movable comb, …, an Mth fixed comb and an Mth movable comb, wherein M is an even number which is more than or equal to 4;
the movable comb, the fixed anchor points and the basal layer are all grounded, the second fixed comb, the fourth fixed comb, … and the M fixed comb are pressurized to generate a tangential electrostatic force in a leftward direction, the elastic beam is driven to bend by the tangential electrostatic force in the leftward direction and rotate around a virtual axis point in the leftward direction, and at the moment, the movable comb is arranged between the second movable comb and the second fixed comb, the movable comb is arranged between the fourth movable comb and the fourth fixed comb, …, the movable comb is arranged between the M movable comb and the M fixed comb, the movable comb is arranged between the first fixed comb and the first movable comb, the movable comb is arranged between the third fixed comb and the third movable comb, …, and the fixed comb is arranged between the M-1 fixed comb and the movable comb is arranged far away from each other.
According to actual requirements, the designed rotation angle can be within 2 degrees, and the size of the whole structure is controlled.
The invention has the beneficial effects that:
1) the invention applies the protruding comb teeth to the MEMS driver rotating around the virtual axis point, and the distance between the movable comb teeth and the fixed comb teeth is smaller than that between the manufactured comb teeth after voltage is applied; the front end of movable broach and the rear end of fixed broach, the front end of fixed broach and the rear end of movable broach have formed mated broach respectively, promptly in the same structure length, can set up more and be used for the drive to the broach, help reducing drive voltage, make things convenient for external circuit to make.
2) The invention adopts the design of rotating around the virtual axis point, and when the invention is applied to an external cavity tunable laser, the invention can be stuck above the movable comb teeth or the outer side surface of the radial truss is manufactured into a grating or a plane mirror, thereby realizing the mode jump-free tuning of the laser.
Drawings
FIG. 1 is a schematic diagram of one configuration of a projected comb-based MEMS actuator of the present invention;
FIG. 2 is a schematic structural view of the protruding comb teeth of the present invention;
FIG. 3 is a schematic cross-sectional view of the MEMS actuator of FIG. 1 taken along cut line AB;
FIG. 4 is an enlarged view of portion C of FIG. 1 with no voltage applied;
FIG. 5 is an enlarged view of portion C of FIG. 1 after application of a voltage;
the comb comprises a movable part 1, a fixed comb 2, a fixed anchor point 3, a base layer 4, a radial truss 5, an arc truss 6, a movable comb 7, an elastic beam 8, a virtual axis point 9, a movable comb tooth 10, a fixed comb tooth 11, a connecting beam 12, a narrow comb tooth at the front end 13, a wide comb tooth at the rear end 14 and a protruding comb tooth 15.
The specific implementation mode is as follows:
in order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific examples, but not limited thereto, and the present invention is not described in detail and is in accordance with the conventional techniques in the art.
Example 1:
an MEMS driver based on protruding comb teeth is disclosed, as shown in figures 1-5, and comprises a movable part 1, a fixed comb 2, fixed anchor points 3 and a substrate layer 4, wherein the fixed comb 2 and the fixed anchor points 3 are fixed on the substrate layer 4;
the movable part 1 comprises a radial truss 5, an arc truss 5, a movable comb 7 and an elastic beam 8, wherein the arc truss 6 is arranged at an arc position taking an imaginary axis point 9 as a circle, the radial truss 5 is arranged along the radius direction, the movable comb 7 comprises a plurality of movable comb teeth 10, the movable comb 7 is formed by connecting the plurality of movable comb teeth 10 through the radial truss 5, the radial truss 5 and the arc truss 6 are connected at an intersection point, the fixed end of the elastic beam 8 is connected with a fixed anchor point 3, the connection mode is as shown in figure 3, the free end of the elastic beam 8 is connected with the radial truss 5, the elastic beam 8 is arranged along the radius direction taking the imaginary axis point 9 as the circle, in the invention, the movable part 1 is only connected with the fixed anchor point 3 through the elastic beam 8, and other parts are all movable;
the fixed comb 2 comprises fixed comb teeth 11 and a connecting beam 12, one side of each fixed comb tooth 11 is connected through the connecting beam 12, and the fixed comb 2 and the movable comb 7 are distributed in a pair in a crossed manner;
the movable comb teeth 10 and the fixed comb teeth 11 are protruding comb teeth 15, as shown in fig. 2, the protruding comb teeth include front narrow comb teeth 13 and rear wide comb teeth 14 which are connected in front and rear, the lengths of the front narrow comb teeth 13 and the rear wide comb teeth 14 are arcs with the virtual axis point 9 as a center, and the protruding comb teeth are located at arc positions corresponding to the radii. The connecting side center of the front narrow comb teeth 13 and the connecting side center of the rear wide comb teeth 14 are connected to form protruding comb teeth which can be used as movable comb teeth or fixed comb teeth. When voltage is applied, the movable part 1 rotates around the virtual axis point 9, and the rotation power is provided by electrostatic force generated by voltage difference between the movable comb teeth 10 and the fixed comb teeth 11.
Example 2:
an MEMS actuator based on protruding comb teeth has a structure as shown in embodiment 1, except that the corresponding degrees of the central angles of all the front narrow comb teeth 13 are the same and 2 °, the widths of all the front narrow comb teeth 13 are equal to the central angles multiplied by the corresponding radii, and the widths are 5 μm;
the central angles corresponding to all the rear-end wide comb teeth 14 are the same, and are 2.5 °, and the width of the rear-end wide comb teeth 14 is equal to the central angle, corresponds to the radius, and is 13 um.
Example 3:
an MEMS actuator based on protruding comb teeth is constructed as shown in embodiment 1 except that the pitch between the adjacent two rear-end wide comb teeth 14 of movable comb teeth 10 and the pitch between the adjacent two rear-end wide comb teeth 14 of fixed comb teeth 11 are both 9 um.
When no voltage is applied, the distance H1 between the distal end narrow comb tooth 13 of the movable comb tooth 10 and the distal end narrow comb tooth 13 of the fixed comb tooth 11 is 6um to 8um, as shown in fig. 4. The pitch H2 is preferably 2um after the voltage is applied, i.e., after the narrow comb teeth at the front end are inserted into the wide comb teeth at the rear end, as shown in FIG. 5, which is less demanding on the process.
Example 4:
an MEMS actuator based on protruding comb teeth is structurally shown in embodiment 1, except that the outermost arc of a movable comb tooth 10 corresponds to a radius of 3540um, the outermost radius of an arc-oriented truss 6 corresponds to a radius of 3600um, the arc-oriented truss 6 corresponds to a central angle of 39 degrees, and the widths of the arc-oriented truss 6 and the radial truss 5 are both 30 um;
the MEMS driver comprises 4 pairs of fixed combs and movable combs, which are symmetrically distributed in the arc truss 6 and symmetrically distributed around the elastic beam 8; the number of pairs of teeth in each pair of the fixed comb 2 and the movable comb 7 is 50.
Example 5:
an MEMS actuator based on protruding comb teeth is constructed as shown in embodiment 4, except that the number of elastic beams 8 is half of the number of pairs of fixed combs 2 and movable combs 7, and two pairs of comb teeth adjacent to the elastic beams 8 are symmetrically distributed about the elastic beams 8;
the length of the flexible beam 8 is 970um, the width is 7um, and a plurality of flexible beams 8 are symmetrically distributed in the arc truss 6, so that the flexible beams have enough elastic coefficient to enable the driver to rotate by more than 1.5 degrees on one side and rotate around the virtual axis point 3 under proper voltage.
Example 6:
an MEMS actuator based on protruding comb teeth is constructed as shown in embodiment 1, except that the movable part 1, fixed comb 2, fixed anchor 3 and substrate layer 4 are made of silicon, and the surfaces of fixed anchor 3 and connection beam 12 are plated with gold to serve as electrodes for grounding movable comb teeth 10 and supplying power to fixed comb teeth 11.
The thickness H3 of the movable part 1 is 50-70 um.
Example 7:
an MEMS driver based on protruding comb teeth is structurally shown in embodiment 1, except that a movable comb 7, a fixed anchor point 3 and a substrate layer 4 are all grounded to control the voltage of a fixed comb 2, a front narrow comb tooth 13 of a movable comb tooth 10 applying voltage corresponding to the fixed comb 2 is inserted into a gap between rear wide comb teeth 14 of two adjacent fixed comb teeth, as shown in FIG. 5, arc side edges of the front narrow comb tooth 13 and the rear wide comb tooth 14 are two electrodes, a tangential capacitance effect and a radial capacitance effect are formed between the two electrodes, and a tangential electrostatic force is generated due to the tangential capacitance effect and drives a free end of an elastic beam 8 to bend to enable a movable part 1 to rotate around a virtual axis point 9, wherein the formula of the tangential electrostatic force is as follows
In the formula (1), N is the number of teeth on one comb, ε is a dielectric constant, V is a voltage difference between the movable teeth and the fixed teeth, H is a thickness H3 of the movable portion, and g is an arc-side distance H2 between the front-end narrow teeth and the rear-end wide teeth after voltage application.
According to the formula (1), when the front end narrow comb tooth is to be inserted into the gap between the rear end wide comb teeth of the adjacent two fixed comb teeth, the interval between the front end narrow comb teeth of the fixed comb tooth and the movable comb tooth becomes the interval between the front end narrow comb tooth of the fixed comb tooth (or the movable comb tooth) and the rear end wide comb tooth of the movable comb tooth (or the fixed comb tooth), and the tangential electrostatic force increases, so that the drive displacement increases.
Example 8:
according to the working method of the MEMS driver based on the protruding comb teeth, the number of pairs of the fixed comb 2 and the movable comb 7 is 4, the number of the elastic beams 8 is 2, and the number of the combs in the MEMS driver from left to right is as follows: the movable comb 2, the fixed anchor points 3 and the basal layer 4 are all grounded, the first fixed comb and the third fixed comb are pressurized to generate tangential electrostatic force in the right direction, the elastic beam 8 is driven to bend by the tangential electrostatic force in the right direction and rotates towards the right side around an imaginary axis point, and at the moment, the first movable comb and the first fixed comb, the third movable comb and the third fixed comb are close to each other, and the second fixed comb and the second movable comb and the fourth fixed comb and the fourth movable comb are far away from each other.
Example 9:
according to the working method of the MEMS driver based on the protruding comb teeth, the number of pairs of the fixed comb 2 and the movable comb 7 is 4, the number of the elastic beams 8 is 2, and the number of the combs in the MEMS driver from left to right is as follows: the comb comprises a first movable comb, a first fixed comb, a second movable comb, a third fixed comb, a fourth fixed comb and a fourth movable comb, wherein the movable comb 2, the fixed anchor points 3 and the basal layer 4 are all grounded, the second fixed comb and the fourth fixed comb are pressurized to generate a tangential electrostatic force in a left direction, the elastic beam 8 is driven to bend by the tangential electrostatic force in the left direction and rotates around a virtual axis point to the left side, at the moment, the second movable comb and the second fixed comb as well as the fourth movable comb and the fourth fixed comb start to approach each other, and the first fixed comb and the first movable comb and the third fixed comb and the third movable comb are all far away from each other.
It should be noted that the driver structure of the present invention is also applicable to other parameters such as different connecting modes of the front narrow comb teeth and the rear wide comb teeth corresponding to the central angle, the radius and the width, different connecting modes of the front narrow comb teeth and the rear wide comb teeth, different distances between the movable comb teeth and the fixed comb teeth, a crossing mode, different radial truss lengths and widths, different arc truss corresponding to the central angle, the radius and the width, different lengths and widths of the elastic beam, different widths and lengths of the connecting beam, different comb tooth pairs of each pair of combs, different comb pairs, different structural thicknesses, etc. As mentioned above, the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. An MEMS driver based on protruding comb teeth is characterized by comprising a movable part, a fixed comb, fixed anchor points and a substrate layer, wherein the fixed comb and the fixed anchor points are fixed on the substrate layer;
the movable part comprises a radial truss, an arc truss, a movable comb and an elastic beam, the arc truss is arranged at an arc position taking a virtual axis point as a circle, the radial truss is arranged along the radius direction, the movable comb comprises a plurality of movable comb teeth, the movable comb teeth are connected through the radial truss, the radial truss is connected with the arc truss at an intersection point, the fixed end of the elastic beam is connected with the fixed anchor point, the free end of the elastic beam is connected with the arc truss, and the elastic beam is arranged along the radius direction taking the virtual axis point as the circle;
the fixed comb comprises fixed comb teeth and a connecting beam, one side of each fixed comb tooth is connected through the connecting beam, and the fixed comb and the movable comb are distributed in a crossed mode in pairs;
the movable comb teeth and the fixed comb teeth are protruding comb teeth, the protruding comb teeth comprise front-end narrow comb teeth and rear-end wide comb teeth which are connected in a front-back mode, the lengths of the front-end narrow comb teeth and the rear-end wide comb teeth are arcs with virtual axis points as circle centers, and the protruding comb teeth are located on arc positions corresponding to the radii.
2. The MEMS actuator based on protruding comb teeth of claim 1, wherein the number of central angles corresponding to the front narrow comb teeth is 1.5-3 °, and the width of the front narrow comb teeth is 5-8 μm;
the central angle degree that the wide broach of rear end corresponds is 2 ~ 3.5, the width of the wide broach of rear end is 13 ~ 16 um.
3. The MEMS projected-comb-tooth-based actuator according to claim 1, wherein the pitch between the adjacent two rear-end wide comb-teeth of the movable comb-teeth and the pitch between the adjacent two rear-end wide comb-teeth of the fixed comb-teeth are both 9 to 18 um;
when no voltage is applied, the distance between the front end narrow comb teeth of the movable comb teeth and the front end narrow comb teeth of the fixed comb teeth is 6um to 8 um.
4. The projected comb-based MEMS actuator of claim 1, wherein the outermost arc of the movable comb corresponds to a radius of 3540um, the outermost arc of the radial truss corresponds to a radius of 3600um, the corresponding center angle of the arc of the radial truss is 39-45 °, and the widths of the arc of the radial truss and the arc of the radial truss are both 30-32 um;
the MEMS driver comprises 4-8 pairs of fixed combs and 4-8 pairs of movable combs, and the number of pairs of comb teeth in each pair of fixed combs and movable combs is 45-50 pairs, so that the size of the driver is small, the radius distance of the driver around a virtual axis point is proper, and enough driving force is provided for enabling the driver to rotate by more than 1.5 degrees on one side.
5. The protruding comb-tooth-based MEMS actuator of claim 4, wherein the number of the elastic beams is half of the number of pairs of the fixed comb and the movable comb, and two pairs of comb teeth close to the elastic beams are symmetrically distributed about the elastic beams;
the length of elastic beam is 850 ~ 1000um, and the width is 7 ~ 9um, and a plurality of elastic beams are in arc is to truss in the symmetric distribution.
6. The projected comb-tooth-based MEMS actuator according to claim 1, wherein the movable portion, the anchor combs, the anchor anchors, and the base layer are all made of silicon, and the surfaces of the anchor anchors and the connection beams are plated with gold to serve as electrodes.
7. The projected comb-tooth-based MEMS actuator of claim 1, wherein the movable portion has a thickness of 50-70 um.
8. The MEMS actuator according to claim 1, wherein the movable comb, the fixed anchor and the substrate are grounded to control the voltage of the fixed comb, the narrow front comb of the movable comb corresponding to the voltage applied to the fixed comb is inserted into the gap between the wide back comb of two adjacent fixed combs, the two electrodes are disposed on the arc sides of the narrow front comb and the wide back comb, a tangential capacitive effect and a radial capacitive effect are formed between the two electrodes, and a tangential electrostatic driving force is generated due to the tangential capacitive effect to drive the free end of the elastic beam to bend and rotate the movable portion around the virtual axis point, wherein the tangential electrostatic force is expressed as follows
In the formula (1), N is the number of comb teeth on a comb, ε is a dielectric constant, V is a voltage difference between movable comb teeth and fixed comb teeth, H is a thickness H1 of the movable portion, and g is an interval H2 between arc sides of front-end narrow comb teeth and rear-end wide comb teeth.
9. The operating method of the protruding comb-tooth-based MEMS actuator as claimed in claim 1, wherein the number of pairs of the fixed comb and the movable comb is M pairs, the number of the elastic beams is M/2, and the MEMS actuator has the following combs distributed from left to right: the comb comprises a first movable comb, a first fixed comb, a second movable comb, a third fixed comb, a fourth movable comb, …, an Mth fixed comb and an Mth movable comb, wherein M is an even number which is more than or equal to 4;
the movable comb, the fixed anchor points and the basal layer are all grounded, the first fixed comb, the third fixed comb, … and the M-1 fixed comb are pressurized to generate tangential electrostatic force in the rightward direction, the elastic beam is driven to bend by the tangential electrostatic force in the rightward direction and rotates around the virtual axis point to the right side, and at the moment, the first movable comb and the first fixed comb, the third movable comb and the third fixed comb, …, the M-1 movable comb and the M-1 fixed comb are all close to each other, the second fixed comb and the second movable comb, the fourth fixed comb and the fourth movable comb, and the M fixed comb and the M movable comb are all far away from each other.
10. The operating method of the protruding comb-tooth-based MEMS actuator as claimed in claim 1, wherein the number of pairs of the fixed comb and the movable comb is M pairs, the number of the elastic beams is M/2, and the MEMS actuator has the following combs distributed from left to right: the comb comprises a first movable comb, a first fixed comb, a second movable comb, a third fixed comb, a fourth movable comb, …, an Mth fixed comb and an Mth movable comb, wherein M is an even number which is more than or equal to 4;
the movable comb, the fixed anchor points and the basal layer are all grounded, the second fixed comb, the fourth fixed comb, … and the M fixed comb are pressurized to generate a tangential electrostatic force in a leftward direction, the elastic beam is driven to bend by the tangential electrostatic force in the leftward direction and rotate around a virtual axis point in the leftward direction, and at the moment, the movable comb is arranged between the second movable comb and the second fixed comb, the movable comb is arranged between the fourth movable comb and the fourth fixed comb, …, the movable comb is arranged between the M movable comb and the M fixed comb, the movable comb is arranged between the first fixed comb and the first movable comb, the movable comb is arranged between the third fixed comb and the third movable comb, …, and the fixed comb is arranged between the M-1 fixed comb and the movable comb is arranged far away from each other.
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| CN2878348Y (en) * | 2005-12-16 | 2007-03-14 | 北京工业大学 | Microstructure single direction bending pulling fatigue experimental device |
| CN200993629Y (en) * | 2006-11-10 | 2007-12-19 | 北京工业大学 | MEMS tensile torsion fatigue performance experiment device |
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| CN105607249A (en) * | 2015-12-21 | 2016-05-25 | 西安励德微系统科技有限公司 | Micro-torsion mirror driven by one-side unequal height comb teeth |
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| KR100837405B1 (en) * | 2006-11-03 | 2008-06-12 | 삼성전자주식회사 | MEMS comb device |
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| CN2878348Y (en) * | 2005-12-16 | 2007-03-14 | 北京工业大学 | Microstructure single direction bending pulling fatigue experimental device |
| CN200993629Y (en) * | 2006-11-10 | 2007-12-19 | 北京工业大学 | MEMS tensile torsion fatigue performance experiment device |
| US9036231B2 (en) * | 2010-10-20 | 2015-05-19 | Tiansheng ZHOU | Micro-electro-mechanical systems micromirrors and micromirror arrays |
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