CN1844937A - High-sensitivity MEMS photoelectric galvanometer, making and detecting method thereof - Google Patents
High-sensitivity MEMS photoelectric galvanometer, making and detecting method thereof Download PDFInfo
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Abstract
The invention relates to an optical electric galvanometer, based on Micro-Electronic Mechanic System (MEMS). It is characterized in that: it use micro mechanical technique to prepare the screw coil MEMS torsion micro lens; it can avoid amplify circuit, that directly inputting the tested current or low-frequency weak current into driving coil, to be arranged in the strong magnetic field generated by external permanent magnet; the driving coil drives the micro lens to deflect from original position by the torque generated by Lorentz force; it uses dual optical fiber collimator to test the characters that sensitive to the angle; according to the relationship between the optical signal loss and the torsion angle, via optical electric conversion and signal processing, attaining the current value. The invention can avoid amplify circuit at the input end, to attain amp level and pF level, to overcome the defects of noise disturb and excursion when amplifying the micro weak current signal. And it can realize the optical electric separation at input and output ends synchronously, with small volume, simple structure, lower cost and better anti-vibration ability.
Description
Technical field
The present invention relates to a kind of highly sensitive microelectromechanical systems photoelectricity galvanometer and making thereof, detection method, is a kind of photoelectricity galvanometer that is applied to the detection ampere of technical fields such as metrology and measurement, electric power, biology, semiconductor, chemical analysis to skin peace magnitude electric current.
Background technology
The monitoring of weak current and detection technique are more and more used in a plurality of fields such as feeble signal precision measurement, bioelectric current detection, semiconductor, electric power, chemical analysis, commercial production.The Detection ﹠ Controling of weak current have important effect at metering field, and sensitivity that the checkout equipment of weak current can reach and precision also are subjected to more attention; Bioelectrode is the important tool of biological phenomena on the research molecular level, it mostly is current-output type greatly, current signal is subjected to multiple bioelectricity interference in the biosome usually, and the high-sensitivity detection of weak current signal has very important meaning for the research of enzyme reaction; Semiconductor devices is complicated day by day, and medium thickness and grid length constantly reduce, and the control of little electric current also is essential with monitoring in the semi-conductor industry; In the electric system, the insulation leakage current of power plant, transforming plant DC operation circuit need carry out precision equally and detect; The variation of little electric current in the continuous monitoring underground water (or little greatly naturally current electric fields) is one of effective way that possible capture that earthquake precursors changes; Be applied to microenvironment and characterize and the Electroanalytical Chemistry of measuring, have only small electric current to pass through on the ultramicroelectrode, need accurate current sensing means; Others are such as the electric current that detects ionic charge, and the occasions such as mensuration of the estimation of gas ionization rate, cell membrane potential, all must make measurement to little electric current.
Present detection for Weak current, be the digital galvanometer [Xiao Xiaomin that adopts amplifier mostly, Yang Chuanwang, Zhao Yilin. proportional current amplifier and the application [J] in little current transformer verification thereof, electrical measurement and instrument, 2002,39 (438): 51-55.], as adopt electrometer tube, adopt extraordinary bipolar transistor, adopt technotron or isolated gate FET, the micro current amplifier of dynamic condenser formula.The minimum detectable electric current of a weak current amplifier is subjected to the restriction of several factors, wherein mainly is subjected to the influence of amplifier noise and drift.Amplifier also amplifies noise when signal is amplified, and particularly " 1/f " interference of noise of the direct current of amplifier leakage current or interchange low frequency signal exerts an influence to measurement.The micro current amplifier made from the strict vacuum tube of selecting can reach very high sensitivity in early days, and volume is big, temperature is floated serious fatal shortcoming but vacuum tube has.Now micro current amplifier generally all adopts the integrated transporting discharging chip manufacturing, but is satisfying that low noise disturbs, having difficulties in the low drift, requirement than fast-response.Operational amplifier also exists problems such as offset voltage, offset current, bias current and temperature drift, through the continuous accumulation of integrating capacitor, the phenomenon of so-called " integrator drift " occurs, causes very big error to measurement.
The method of another kind of detection weak current need not amplifier [Xiang Xiaomin, Ceng Weilu, height is learnt military affairs. a kind of new-type magnetic modulating dc current measuring method [J], HUST's journal, 1998,26 (12): 64-67.], its principle mostly is the variation of measurement by the magnetic field of electric current generation, as Hall element etc., but its detection sensitivity is all lower, is difficult to reach milliampere below the level.At present, the measurement of the following direct current Weak current of contactless 1mA is difficult to realize that if adopt Hall element, even adopt the magnetic focusing method, minimum current just responds greatly more than 20mA.Traditional comparator is measured the current precision height, but its uses closed-loop measuring principle, and the line construction complexity is usually used in Super-Current Measurement, and in the least, little electric current of microampere order is difficult to measure with the method, main cause is that stability is very poor because feedback current is too little.The low-temperature superconducting comparator that has superconducting quantum interference device can reach very high measuring accuracy (10
-12A), but this appliance requires works at low temperatures, and at room temperature reading of data needs accurate temperature control and compensation system, and the costing an arm and a leg of a whole set of instrument
Summary of the invention
The present invention be directed to galvanometric in the past shortcoming, galvanometric design of a kind of highly sensitive MEMS photoelectricity and making thereof, detection method are provided, to reach the directly and accurately measurement of ampere to skin peace magnitude electric current, sensitivity improves greatly compared with Hall element for it, compare with the galvanometer that adopts amplifier, need not complicated circuit.The design parameter of the current detecting of different magnitudes is made respective change.This photoelectricity galvanometer based on MEMS need not the low-frequency weak signal amplifier of complex and expensive, has reduced the error of the noise generation that causes amplification when amplifier amplifies signal.
Described MEMS photoelectricity galvanometer, responsive part is a spiral winding formula MEMS torsion mirror (Fig. 1, Fig. 2), and primary structure comprises that both-end props up the lead-in wire (2) of formula twisted planar (5), metal driving coil (3), coil and electrode and the mirror surface (7) at the torsion structure back side admittedly; The test section is to the highstrung optoelectronic angle detection system of angle (Fig. 7), by light source driving circuit (12), light source (13), double-fiber collimator (14), input optical fibre (15), output optical fibre (16), light power meter (17), photoelectric commutator (18), amplifier (19), display formations such as (20).Make spiral winding formula MEMS torsion mirror (Fig. 1, Fig. 2) by micromechanical process, wherein metal driving coil (3) is made on the twisted planar (5), the lead-in wire of coil and electrode (2) is isolated by insulation course and metal driving coil (3), mirror surface (7) is positioned at the back side of twisted planar, and twisted planar (5) forms the both-end fixed support structure with beam (4).The lead-in wire of coil and electrode (2) is produced on metal driving coil (3) lower floor (Fig. 5) by insulation course, also can be on the upper strata (Fig. 6).Isolate the micro mirror back side and can make damping coil (8) (Fig. 4), also can not make damping coil (Fig. 3).Whole M EMS torsion mirror (Fig. 1, Fig. 2) is placed in the high-intensity magnetic field that adds the permanent magnet generation by propping up.Light source (13) and driving circuit (12) thereof are connected with double-fiber collimator (14) by input optical fibre (15), the end face of double-fiber collimator is towards the mirror surface (7) of MEMS torsion mirror, be connected to light power meter (17) by output optical fibre (16), then be connected (20) with display by photoelectric commutator (18), amplifier (19).During measuring-signal, the magnetic field that the MEMS torsion mirror vertically places permanent magnet to produce by support; Direct current weak current to be measured is directly imported metal driving coil (3), drive coil will be subjected to the moment loading that Lorentz force produces, drive torsion structure and depart from initial angle position, the light that light source (13) sends is input to double-fiber collimator (14) by input optical fibre (15), rotation information is converted into optical information, be sent to pick-up unit by output optical fibre (16), detected by light power meter (17) and photoelectric commutator (18) amplifier (19), display (20) can obtain current information.
Described MEMS photoelectricity galvanometer, twisted planar can be arbitrary shapes such as rectangle, circle, polygon, the metal driving coil can be that rectangle, parallelogram, polygon or other can produce the arbitrary shape of effective torque, torsion beam can be rectangle, shape such as trapezoidal, also can be composite beam structures such as folded beam.
Described MEMS photoelectricity galvanometer, the metal driving coil of MEMS torsion mirror, lead-in wire between coil and the electrode can be by sputter, electroplate or other MEMS technology making, coil can be by copper, gold, one or more material of aluminium or other conductive material etc., lead-in wire between the coil outside and the electrode and metal driving coil are at same one deck, and the lead-in wire between coil inboard and the electrode is isolated upper strata or the lower floor that is made in the metal driving coil by insulation course, also can be with in the coil, the lead-in wire in the outside is made in the upper strata or the lower floor of metal driving coil simultaneously; Drive coil can change the number of turn, can make one deck, also can isolate by insulation course and make multilayer, satisfies the requirement of different measuring scope sensitivity, and measurement range can cover ampere to skin peace magnitude.
Described MEMS photoelectricity galvanometer, substrate, twisted planar, torsion beam can also can be processed by different materials by same material, as monocrystalline silicon, silicon nitride, silicon dioxide, indium phosphide, polymkeric substance etc.The thickness of substrate, twisted planar, torsion beam can be identical, also can be different, form the twisted planar ledge structure different with torsion beam thickness, and film can form by technologies such as growth or corrosion thinnings.
Described MEMS photoelectricity galvanometer, the deielectric-coating of making high reflectance at the back side of MEMS torsion mirror also can be made metal film (as gold, silver, aluminium etc.) as the reflection micromirror by technologies such as sputter, plating as mirror surface.The reflection micromirror can be produced on the back side of membrane structure, also can be produced on the front of membrane structure, can make closed damping coil at the MEMS torsion mirror back side simultaneously, to reach the effect that reduces stabilization time, insulation course between the double layer of metal coil can be silicon dioxide, silicon nitride, also can be other insulating material such as polyimide.
Described MEMS photoelectricity galvanometer, magnetic field are to add permanent magnet, and as the stationary magnetic field that neodymium iron boron, Rhometal etc. produce, permanent magnet can be fixed by outside support, also can directly be produced on the MEMS structure by the sputter thin magnetic film; Magnetic field also can be the constant or alternating magnetic field that energising long straight conductor or solenoid produce, and can detect DC current according to static drift angle, also can detect the little electric current of low-frequency ac according to stable oscillation amplitude.
Described MEMS photoelectricity galvanometer, utilize double-fiber collimator that the highstrung characteristic of angle is detected deflection angle, obtain the loss of light signal and the relation of windup-degree, measure little current value through after Optical Fiber Transmission, opto-electronic conversion and the signal Processing, also can use other method that angle is detected, detect optically-coupled as detect method that the input and output light intensity change, three optical fiber by two optical fiber, utilize wire coil to detect the method for all optics such as induction electromotive force, non-optical detection angles.
Described MEMS photoelectricity galvanometer, the selection of device parameters can be according to following steps: (1) is according to calculating moment of inertia, the damping of parameter with the front metal drive coil and back side damping coil parameter (number of turn, length, single-turn circular coil width, coil spacing) the calculating entire device of the parameter initial value (length) of rotational plane, lead-in wire.(2) according to the resistance of the calculation of parameter device of the lead-in wire of wire coil and coil.(3) according to the driving moment of different stationary magnetic field calculating devices.(4) deflection angle of device under the calculating device steady state (SS).(5) obtain required sensitivity, resolution, error equivalence according to restrictive condition (damping condition, shear stress, strength condition, time constant etc.), process conditions and parameter initial value.(6),, calculate parameters such as rational torsion beam length according to the torsional rigidity of the deflection angle and the beam of device according to the sensitivity of desired measuring current.(7) utilize ANSYS software that device carried out static analysis, thermal analysis and emi analysis.(8) revise repeatedly and definite parameter according to above several steps.
Described MEMS photoelectricity galvanometer, agent structure spiral winding formula MEMS torsion mirror can be made according to following steps: the two-sided oxidation of (1) silicon chip, the protection of front gluing, backsizing photoetching development, corrosion oxidation silicon, remove photoresist, purpose that KOH anisotropic wet corrosion realizes the attenuate silicon chip; (2) front gluing photoetching, sputter (evaporation, plating) metal, acetone remove photoresist, and form the connecting line of MEMS coil and electrode; (3) positive PECVD (plasma chemistry vapor phase deposition) silicon dioxide (perhaps silicon nitride, also can coating polyimide) as insulation course, the front gluing photoetching development of MEMS coil and connecting line, erode away the interconnected pores of MEMS coil and connecting line; (4) front gluing photoetching development, sputter (evaporation) metal, acetone remove photoresist (also can pass through electric plating method) make MEMS coil and electrode; (5) mirror surface (close damper coil) of high reflectance is made in back spraying glue, photoetching development, sputter (evaporation, plating); (6) front gluing photoetching development by the dry etch process releasing structure of silicon, etches MEMS torsion mirror structure.
Described MEMS photoelectricity galvanometer in order to prevent the influence of humidity, air oxidation, designs suitable shell, and device is encapsulated, and comprises that the circuit package of playing lead-in wire etc. and the part of detecting of optical coupled encapsulate.The MEMS torsion mirror adds in the high-intensity magnetic field that permanent magnet produces by being placed on, the mirror surface of double-fiber collimator on the MEMS torsion mirror, and input is connected double-fiber collimator and driving, testing circuit with output optical fibre.
Highly sensitive MEMS photoelectricity galvanometer provided by the present invention has following advantage:
1, the present invention is made into a kind of photoelectricity galvanometer that can detect ampere to skin peace magnitude by MEMS technology.Compare with the common low current sensor that utilizes amplifying circuit, input circuit need not amplifier, has overcome low current signal and has amplified the noise that causes and the technical matters of drift, can realize the photoelectricity isolation of input end and output terminal simultaneously.Light signal adopts the Sine Modulated method, makes direct current or low-frequency current signal be transformed to the intermediate frequency photo-signal of arrowband, helps highly sensitive detection.
2, utilize double-fiber collimator that the highstrung characteristic of angle is detected the micro mirror windup-degree, and can be by regulating the pre-drift angle of double-fiber collimator, reach the double-fiber collimator resolution different to angle, thereby satisfy the requirement that different weak currents detect, can obtain wider application.
3, double-fiber collimator detects angle, is quick on the draw, the degree of accuracy height, is highly suitable for vertiginous measurement of angle.Optical fiber has good biography light characteristic, and is low to the loss of light wave, and the good insulating of optical fiber is not subjected to electromagnetic interference (EMI).
4, simple, the compact conformation of the principle of the invention, volume reduces greatly, is convenient to practical applications such as transportation, installation.The present invention will be reflected the back side that micromirror is made in torsion structure, further reduce the overall dimensions of device.
5, the present invention processes on substrate by MEMS technologies such as oxidation, photoetching, sputter, plating, because the silicon processing technique maturation can realize producing in batches, reducing production costs greatly.
6, the wire coil of Qu Donging can be made one deck, also can isolate by insulation course and make multilayer.Can change the number of turn of drive coil and length and width height, the length and width height of torsion beam, the parameters such as length of twisted planar, can satisfy different measurement requirement, cover ampere to skin peace (10
-12A) magnitude.
7, the present invention adopts the both-end of symmetry to prop up torsion structure admittedly, combines with the angular detection mode of double-fiber collimator, has reduced the influence of external shock to measuring.
8, the designed photoelectricity galvanometer of the present invention improves greatly compared with Hall element resolution and (can detect 10
-12The electric current of A), compares, need not complicated circuit with the digital galvanometer of using amplifier; Compare with the low-temperature superconducting comparator, do not need low-temperature refrigeration device and compensation system.
9, the present invention adopts the inboard lead-in wire with electrode of coil to be made in the structure (Fig. 6) of metal driving coil lower floor, because the metal driving coil is positioned at the upper strata, is not subjected to the influence of thickness of insulating layer and climbing effect, can make thicklyer, reduce the internal resistance of device, improve measuring accuracy accordingly.
10, there is the device (Fig. 4) of close damper coil at the back side of the present invention's design, under the situation that does not influence the device overall dimensions, greatly reduce the stabilization time of vibrations, calculate show the close damper coil design can with stabilization time by dropping to a millisecond magnitude tens of seconds.
11, the present invention design reverses the film device different with torsion beam thickness, the thickness of beam separated with the thickness of twisted planar design, the coefficient of torsion that can the design flexible beam reaches the requirement that increases sensitivity or reduce technology difficulty under the situation that does not change sensitivity.
Description of drawings
Fig. 1 is the twisted planar MEMS torsion mirror front view (FV) identical with torsion beam thickness.Wherein 1 is support, the 2nd, and the lead-in wire of coil, the 3rd, metal driving coil, the 4th, torsion beam, the 5th, twisted planar, the 6th, permanent magnet.
Fig. 2 is the twisted planar MEMS torsion mirror front view (FV) different with torsion beam thickness.Wherein 1 is support, the 2nd, and the lead-in wire of coil, the 3rd, metal driving coil, the 4th, torsion beam, the 5th, twisted planar, the 6th, permanent magnet.
Fig. 3 is the MEMS torsion mirror back view of undamped coil.Wherein 1 is support, the 4th, and torsion beam, the 5th, twisted planar, the 7th, mirror surface.
Fig. 4 is the back view that the MEMS torsion mirror of damping coil is arranged.Wherein 1 is support, the 4th, and torsion beam, the 5th, twisted planar, the 7th, mirror surface, the 8th, closed damping coil.
Fig. 5 is the structure that the lead-in wire of coil inboard is made in metal driving coil upper strata, the 9th, and the lead-in wire between coil inboard and the electrode, the 3rd, metal driving coil.
Fig. 6 is the structure that the lead-in wire of coil inboard is made in metal driving coil lower floor, the 9th, and the lead-in wire between coil inboard and the electrode, the 3rd, metal driving coil.
Fig. 7 is the photoelectricity galvanometer structural representation that figure of the present invention provides, the 10th, MEMS torsion mirror, the 11st, current input terminal line to be measured, the 12nd, light source driving circuit, the 13rd, light source, the 14th, input optical fibre, the 15th, double-fiber collimator, the 16th, output optical fibre, the 17th, light power meter, the 18th, photoelectric commutator, the 19th, amplifier, the 20th, display.
Embodiment
Being made in metal driving coil lower floor (Fig. 6), the back side with the lead-in wire of coil inboard, the device of damping coil (Fig. 4) is arranged is example explanation embodiment, wherein silicon dioxide is insulation course, silicon is substrate, aluminium is as the material of MEMS drive coil and lead-in wire, twisted planar, wire coil, torsion beam all are rectangle, concrete steps following (structure that is positioned at metal driving coil upper strata for undamped coil, lead-in wire can adopt similar step):
1, the selection of device parameters
A, parameter initial value (length), the parameter of lead-in wire and calculating moment of inertia, the damping of front metal drive coil and back side damping coil parameter (number of turn, length, single-turn circular coil width, coil spacing) calculating entire device according to rotational plane.
B, according to the resistance of the calculation of parameter device of the lead-in wire of wire coil and coil.
C, according to the driving moment of different stationary magnetic field calculating devices.
The deflection angle of device under D, the calculating device steady state (SS).
E, obtain required sensitivity, resolution, error equivalence according to restrictive condition (damping condition, shear stress, strength condition, time constant etc.), process conditions and parameter initial value.
F, according to the sensitivity of desired measuring current, according to the torsional rigidity of the deflection angle and the beam of device, calculate parameters such as rational torsion beam length.
G, utilize ANSYS software that device carried out static analysis, thermal analysis and emi analysis.
H, revise repeatedly and definite parameter according to above several steps.
Can be met the device parameters of different test requests according to above constraint condition, at 10
-9The parameter that the test of A electric current can be adopted is: silicon plane length and width height is respectively 4000 μ m, 4000 μ m, 80 μ m; Torsion beam length and width height is respectively 307 μ m, 3 μ m, 80 μ m; The average length of side of MEMS wire coil, live width, spacing, thickness are respectively: 1650 μ m, 70 μ m, 30 μ m, 1 μ m, and the number of turn is 45; Mirror surface length and width height is respectively 1000 μ m, 1000 μ m, 0.5 μ m, the average length of side of damping coil, live width, spacing, thickness are respectively 2500 μ m, 50 μ m, 50 μ m, 1 μ m, the number of turn is 15, for the testing current of other range, can change design parameter accordingly and realize.
2, make mask plate
Simulate the parameter that obtains according to Theoretical Calculation and ANSYS, utilize L-EDIT software to draw the corresponding domain of system, utilize optical means or electron beam lithography to make mask.
3, technology is made
Select backing material, obtain torsion structure, make the mirror surface of high reflectance then at the torsion structure back side by oxidation, sputter, photoetching, plating, etching (dry method or wet method).
The concrete steps following (Fig. 1) of A, twisted planar and torsion beam thickness same structure:
A, the two-sided oxidation of silicon chip (250 microns to 400 microns of thickness) (silicon thickness that oxidated layer thickness erodes is as required determined), the protection of front gluing, backsizing photoetching development, corrosion oxidation silicon, remove photoresist, the purpose of KOH anisotropic wet corrosion realization attenuate silicon chip;
B, front gluing photoetching, sputter (evaporation, plating) aluminium, acetone remove photoresist, and form the connecting line of MEMS coil and electrode;
C, positive PECVD (plasma chemistry vapor phase deposition) silicon dioxide (perhaps silicon nitride, also can coating polyimide) as the insulation course between MEMS coil layer and the connecting line layer, front gluing photoetching development, erode away the interconnected pores of MEMS coil and connecting line;
D, front gluing photoetching development, sputter (evaporation) aluminium, acetone remove photoresist (also can pass through electric plating method) make aluminium MEMS coil and electrode;
The mirror surface (close damper coil) of high reflectance is made in e, back spraying glue, photoetching development, sputter (evaporation, plating);
F, front gluing photoetching development by the dry etch process releasing structure of silicon, etch MEMS torsion mirror structure.
The concrete steps following (Fig. 2) of B, twisted planar and torsion beam thickness different structure:
A, two-sided oxidation form insulation course (silicon thickness that oxidated layer thickness erodes is as required determined);
B, front gluing photoetching, sputter (evaporation, plating) aluminium, acetone remove photoresist, as the lead-in wire of coil;
C, positive sputter silicon dioxide as the insulation course of upper coil and lead-in wire, and erode the silicon dioxide at the crossover position place of interior loop and lead-in wire, make the interconnected pores of upper strata drive coil and lower floor lead-in wire herein;
D, make the lead-in wire of metal driving coil, electrode by technologies such as sputter, photoetching, plating;
The mirror surface (close damper coil) of high reflectance is made in e, backsizing, photoetching development, sputter (evaporation, plating);
F, the back side erode need to carve and wear and the silicon dioxide of beam part, from back side dry etching silicon until reaching the thickness that torsion beam needs;
G, fall to need carve the silicon dioxide that wear part from front etch, dry etching discharges torsion structure.
4, device package
In order to prevent the influence of humidity, air oxidation, design suitable shell, device is encapsulated, comprise that the circuit package of playing lead-in wire etc. and the part of detecting of optical coupled encapsulate.Mode according to Fig. 7 connects entire device, the MEMS torsion mirror is placed in the high-intensity magnetic field that adds the permanent magnet generation by propping up, the mirror surface of double-fiber collimator on the MEMS torsion mirror, input is connected double-fiber collimator and driving, testing circuit with output optical fibre.
5, detect
Adopt double-fiber collimator that the rotational characteristic of MEMS micro mirror is detected.The shared GRIN of the input optical fibre of double-fiber collimator and output optical fibre (gradient index) lens, the light of input optical fibre emission, are being received by output optical fibre through same grin lens through the reflecting surface reflection through the grin lens emission.According to the double-fiber collimator principle as can be known, by the light of its two tail optical fiber inputs, after the condenser lens transmission, light beam can intersect at lens front end point place usually at a certain angle, and this angle is caused from axle by optical fiber, is symmetrical therefore.When vertical optical axis is placed a plane mirror near this intersection point, reversible according to light path, by the light of optical fiber input wherein, will be after the reflection from other optical fiber coupling output, if minute surface deflects, folded light beam produces loss because of not being coupled fully.For the collimating apparatus of 200 μ m of common employing output waist spot, when wavelength is 1550nm just there be than higher sensitivity the optics angle-measuring method, and minute surface only rotates 0.26 °, and coupling loss just can reach 60dB.
Because the distinguishable minimal losses of double-fiber collimator is 0.001dB, and the big more loss that causes of the angle of double-fiber collimator and mirror surface (being half of coupling angle of two optical fiber) is also big more, therefore under different pre-drift angles, same angle changes the loss that causes and changes different, when the pre-drift angle of double-fiber collimator and mirror surface hour, double-fiber collimator is lower to the resolution of angle; When the pre-drift angle of double-fiber collimator was big, double-fiber collimator was higher to the resolution of angle.Requirement according to electric current resolution to be measured, regulate the relative position of double-fiber collimator and minute surface before the test, feasible light process direct reflection by the input of double-fiber collimator root optical fiber, all or part of from other optical fiber output, and by light power meter monitoring loss value, regulate the relative position of double-fiber collimator and minute surface, can obtain the pre-drift angle under the different situations, then Devices Characteristics is detected.
Light source driving circuit makes light source produce the light signal of light power stabilising, the light that light source sends shines the mirror surface of torsion mirror through the input optical fibre of double-fiber collimator, weak current to be measured need not amplifying circuit, directly import drive coil by the incoming line of MEMS torsion mirror, place and add the high-intensity magnetic field that permanent magnet produces, drive coil will be subjected to the moment loading that Lorentz force produces, drive the MEMS torsion mirror and depart from initial angle position, mirror surface is converted into optical information with rotation information, be sent to pick-up unit by output optical fibre, by light power meter and photoelectric commutator, amplifier detects, and display can obtain current information.For different test requests, can change the number of plies, the number of turn and the length and width height of drive coil, the length and width height of torsion beam, the parameters such as length of twisted planar, change the pre-drift angle of double-fiber collimator simultaneously, directly the test ampere is to skin peace (10
-12A) electric current of magnitude, minimum can tell 10
-12The electric current of A.
Claims (10)
1, a kind of photoelectricity galvanometer of microelectromechanical systems comprises responsive part and test section, it is characterized in that:
1) responsive part is a spiral winding formula MEMS torsion mirror, comprises that mainly both-end props up the lead-in wire (2) of formula twisted planar (5), metal driving coil (3), coil and electrode and the mirror surface (7) at the torsion structure back side admittedly; The test section is the optoelectronic angle detection system to angular-sensitive, and it is made of light source driving circuit (12), light source (13), double-fiber collimator (14), input optical fibre (15), output optical fibre (16), light power meter (17), photoelectric commutator (18), amplifier (19), display (20);
2) described spiral winding formula MEMS torsion mirror is made by micromechanical process, wherein metal driving coil (3) is made on the twisted planar (5), the lead-in wire of coil and electrode (2) is isolated by insulation course and metal driving coil (3), mirror surface (7) is positioned at the back side of twisted planar, and twisted planar (5) forms the both-end fixed support structure with beam (4), and whole M EMS torsion mirror is placed in the high-intensity magnetic field that adds the permanent magnet generation by propping up;
3) light source (13) and driving circuit (12) thereof are connected with double-fiber collimator (14) by input optical fibre (15), the end face of double-fiber collimator is towards the mirror surface (7) of MEMS torsion mirror, be connected to light power meter (17) by output optical fibre (16), then be connected (20) with display by photoelectric commutator (18), amplifier (19).
2, press the photoelectricity galvanometer of the described microelectromechanical systems of claim 1, it is characterized in that, lead-in wire between the coil outside and the electrode and metal driving coil are at same one deck, and the lead-in wire between coil inboard and the electrode is made in the upper strata or the lower floor of metal driving coil by the insulation course isolation, or the lead-in wire of coil medial and lateral is made in simultaneously the upper strata or the lower floor of metal driving coil.
By the photoelectricity galvanometer of the described microelectromechanical systems of claim 1, it is characterized in that 3, the spiral winding of the responsive part mirror back side that declines makes or do not make closed damping coil.
4, by the photoelectricity galvanometer of the described microelectromechanical systems of claim 1, it is characterized in that twisted planar is rectangle, circle or polygon; The metal driving coil is that rectangle, parallelogram, polygon or other can produce the arbitrary shape of effective torque; Torsion beam is a rectangle or trapezoidal or for folded beam.
5, by the photoelectricity galvanometer of the described microelectromechanical systems of claim 1, it is characterized in that described magnetic field is the permanent magnet that adds of generations such as neodymium iron boron or Rhometal, or the constant or alternating magnetic field of energising long straight conductor or solenoid generation; Permanent magnet is fixed by outside support or directly is produced on the MEMS structure by the sputter thin magnetic film.
6, make the galvanometric method of photoelectricity of microelectromechanical systems as claimed in claim 1, it is characterized in that the spiral winding or the MEMS micro mirror processing step of responsive part is:
(1) the two-sided oxidation of silicon chip, the protection of front gluing, backsizing photoetching development, corrosion oxidation silicon, remove photoresist, KOH anisotropic wet corrosion thinning silicon chip;
(2) photoetching of front gluing, sputter, evaporation or plating, metal, acetone removes photoresist, and forms the connecting line of MEMS coil and electrode;
(3) positive plasma activated chemical vapour deposition silicon dioxide, silicon nitride or coating polyimide as insulation course, the front gluing photoetching development of MEMS coil and connecting line, erode away the interconnected pores of MEMS coil and connecting line;
(4) front gluing photoetching development, sputter or evaporation, metal, acetone remove photoresist and make MEMS coil and electrode;
(5) mirror surface of high reflectance is made in back spraying glue, photoetching development, sputter, evaporation or plating;
(6) front gluing photoetching development by the dry etch process releasing structure of silicon, etches MEMS torsion mirror structure.
By the galvanometric method for making of photoelectricity of the described microelectromechanical systems of claim 6, be characterised in that 7, the mirror surface of the high reflectance of making is the deielectric-coating of high reflectance or is the metal film of Au, Ag or aluminium.
8, use the galvanometric detection method of photoelectricity of microelectromechanical systems as claimed in claim 1, when it is characterized in that detection signal, the magnetic field that the MEMS torsion mirror vertically places permanent magnet to produce by support; Direct current weak current to be measured is directly imported metal driving coil (3), drive coil will be subjected to the moment loading that Lorentz force produces, drive torsion structure and depart from initial angle position, the light that light source (13) sends is input to double-fiber collimator (14) by input optical fibre (15), rotation information is converted into optical information, be sent to pick-up unit by output optical fibre (16), detected by light power meter (17) and photoelectric commutator (18) amplifier (19), display (20) can obtain current information.
9, by the photoelectricity galvanometer detection method of the described microelectromechanical systems of claim 8, the magnitude of current that it is characterized in that detecting is according to the detected DC current in static drift angle, or the little electric current of low-frequency ac that detects according to stable oscillation amplitude.
10, press the photoelectricity galvanometer detection method of claim 8 or 9 described microelectromechanical systemss, it is characterized in that utilizing double-fiber collimator that the highstrung characteristic of angle is detected deflection angle, obtain the loss of light signal and the relation of windup-degree, measure little current value through after Optical Fiber Transmission, opto-electronic conversion and the signal Processing, also can measure little electric current by the method for electro-optical feedback.The shared grin lens of the input optical fibre of double-fiber collimator and output optical fibre, the light of input optical fibre emission, are being received by output optical fibre through same grin lens through the reflecting surface reflection through the grin lens emission.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101618849B (en) * | 2008-07-03 | 2012-09-26 | 探微科技股份有限公司 | Method for adjusting resonant frequency of torsional micro electro-mechanical component |
| CN102967934A (en) * | 2012-12-04 | 2013-03-13 | 中国科学院苏州纳米技术与纳米仿生研究所 | Electromagnetic-driven micro mirror |
| CN108873314A (en) * | 2017-05-08 | 2018-11-23 | 意法半导体有限公司 | Pass through the stabilisation of the open angle of the micro-reflector of electric current drive control |
| CN110261452A (en) * | 2019-06-13 | 2019-09-20 | 西安交通大学 | The method of the restructural ultramicroelectrode of morphology controllable is prepared based on field drives |
| CN110426843A (en) * | 2019-09-02 | 2019-11-08 | 无锡微视传感科技有限公司 | Two-dimensional scanning micro mirror |
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| JP4102037B2 (en) * | 2001-04-26 | 2008-06-18 | 富士通株式会社 | Micromirror device and manufacturing method thereof |
| CN1278920C (en) * | 2004-08-06 | 2006-10-11 | 中国科学院上海微系统与信息技术研究所 | Torque mirror driver of micro electromechanical system, producing method and use |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101618849B (en) * | 2008-07-03 | 2012-09-26 | 探微科技股份有限公司 | Method for adjusting resonant frequency of torsional micro electro-mechanical component |
| CN102967934A (en) * | 2012-12-04 | 2013-03-13 | 中国科学院苏州纳米技术与纳米仿生研究所 | Electromagnetic-driven micro mirror |
| CN102967934B (en) * | 2012-12-04 | 2016-08-03 | 中国科学院苏州纳米技术与纳米仿生研究所 | A kind of Electromagnetic-drivmicro micro mirror |
| CN108873314A (en) * | 2017-05-08 | 2018-11-23 | 意法半导体有限公司 | Pass through the stabilisation of the open angle of the micro-reflector of electric current drive control |
| CN110261452A (en) * | 2019-06-13 | 2019-09-20 | 西安交通大学 | The method of the restructural ultramicroelectrode of morphology controllable is prepared based on field drives |
| CN110261452B (en) * | 2019-06-13 | 2020-03-24 | 西安交通大学 | Method for preparing reconfigurable ultramicroelectrode with controllable morphology based on magnetic field driving |
| CN110426843A (en) * | 2019-09-02 | 2019-11-08 | 无锡微视传感科技有限公司 | Two-dimensional scanning micro mirror |
| CN114924419A (en) * | 2022-06-15 | 2022-08-19 | 业成科技（成都）有限公司 | Angle adjusting device, head-up display and vehicle |
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