CN105103030B - Self-alignment MEMS device - Google Patents

Self-alignment MEMS device Download PDF

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Publication number
CN105103030B
CN105103030B CN201480013316.2A CN201480013316A CN105103030B CN 105103030 B CN105103030 B CN 105103030B CN 201480013316 A CN201480013316 A CN 201480013316A CN 105103030 B CN105103030 B CN 105103030B
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China
Prior art keywords
capacitance
mems
movable mirror
actuator
light beam
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CN201480013316.2A
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Chinese (zh)
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CN105103030A (en
Inventor
M·梅德哈特
B·莫塔达
A·O·埃尔沙特
M·纳吉
M·加德西夫
B·A·萨达尼
A·N·哈菲兹
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SI Ware Systems Inc
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SI Ware Systems Inc
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Priority claimed from US14/165,997 external-priority patent/US9658053B2/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • G01J3/06Scanning arrangements arrangements for order-selection
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00Measuring instruments characterised by the use of optical techniques
    • G01B9/02Interferometers
    • G01B9/02055Reduction or prevention of errors; Testing; Calibration
    • G01B9/0207Error reduction by correction of the measurement signal based on independently determined error sources, e.g. using a reference interferometer
    • G01B9/02071Error reduction by correction of the measurement signal based on independently determined error sources, e.g. using a reference interferometer by measuring path difference independently from interferometer
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28Investigating the spectrum
    • G01J3/45Interferometric spectrometry
    • G01J3/453Interferometric spectrometry by correlation of the amplitudes
    • G01J3/4535Devices with moving mirror
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/06Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the phase of light
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N2021/3595Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using FTIR
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/0816Optical 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
    • G02B26/0833Optical 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
    • G02B26/0841Optical 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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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Spectrometry And Color Measurement (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)
  • Micromachines (AREA)

Abstract

A kind of MEMS (MEMS) interferometer provides the self calibration of the speculum positioning of movable mirror.Movable mirror is coupled to the MEMS actuator with variable capacitance.MEMS interferometers are included for determining in the capacitance sensing circuit of the capacitance of the MEMS actuator of two or more known positions of movable mirror and for the actuator capacitance in known position to be used to carry out the calibration module of any drift in compensating electric capacity sensing circuit.

Description

Self-alignment MEMS device
Technical field
This patent disclosure relates generally to optical spectra method and interfere measure, and more particularly to MEMS (MEMS) technology Use in optical interdferometer.
Background technology
MEMS (MEMS) refers to that mechanical organ, sensor, actuator and electronic device are existed by micro-processing technology It shares integrated on silicon substrate.For example, microelectronic component is typically manufactured using integrated circuit (IC) technique, and micromechanics group Into component portion is formed to form machinery and electromechanics using the new structure sheaf of the part or addition that are selectively etched out silicon wafer The miromaching of the compatibility of part manufactures.MEMS device in spectroscopic methodology, technology of profiling, environment sensing, refractive index for surveying The use measured in (or material identification) and many other sensor applications is attractive candidate item, is attributed to theirs Low cost, batch processing ability and the compatibility with standard microelectronic device.In addition, the small size of MEMS device contributes in this way MEMS device to mobile and handheld device in it is integrated.
In addition, MEMS technology makes it possible to realize together with its numerous actuation technology new function and the spy of photonic device Sign, such as tuned optical and dynamic sensing application.For example, (electrostatic, magnetic or heat) is activated by using MEMS to control Michael The movable mirror of inferior interferometer can introduce the thin tail sheep in interferometer optics path length, and result can obtain To the differential phase between interfering beam.Final differential phase can be used for stellar interferometer light beam spectral response (for example, Use Fourier transform spectrometry (FTS)), the speed (for example, using Doppler effect) of mobile speculum or simply as optics Phase delay element.
Key components in the accuracy of such interferometer are to determine the position of movable mirror.Traditionally, Laser and auxiliary interferometer have been used to measure mobile mirror position.However, introduce bulky lasing light emitter and additional Interferometer increases the size, cost and complexity of interferometer system.
Accordingly, there exist have with the mechanism of the determining movable mirror position of size, cost and complexity reduced It needs.
Invention content
The embodiment of the present invention provides a kind of self-alignment MEMS (MEMS) for being used to carry out speculum positioning and sets It is standby.MEMS device includes movable mirror and is coupled to movable mirror having variable capacitance with cause its displacement MEMS actuator.MEMS device further comprises maintaining the position that the capacitance of MEMS actuator is mapped to movable mirror Table memory, be coupled to MEMS actuator for sense MEMS actuator capacitance present capacitance sensing circuit, use In access table to determine the Digital Signal Processing of the current location of movable mirror based on the capacitance present of MEMS actuator Device and the corresponding actual capacitance for determining two or more known positions in movable mirror of MEMS actuator To determine the calibration module of the correcting value of the current location to be applied to movable mirror.Digital signal processor uses correction Amount further generates the corrected current location of movable mirror.
In one embodiment, MEMS device further comprises the light for generating the inputs light beam with known wavelength Source, and as movable mirror is moved through generating as the result of the movement of inputs light beam and movable mirror At least two zero crossings of interference pattern, capacitance sensing circuit measure capacitance variations.Digital signal processor is become based on capacitance Change and interference pattern fills table.
In a further embodiment, calibration module will be in the reality of the MEMS actuator of two or more known positions Capacitance each capacitance corresponding in table in border is compared, to calculate the actual capacitance measured capacitance corresponding in table Between corresponding error.In the exemplary embodiment, table represents capacitance sensing curve, and calibration module is bent using capacitance sensing Line and the error calculated are inferred to corrected capacitance sensing curve, and are come really using corrected capacitance sensing curve The fixed correcting value to be applied to current location.
In another embodiment, MEMS device further comprises the wideband light source for generating broad band light beam.Capacitance sensing Circuit determines the first measurement capacitance at the first reference position of movable mirror and second in movable mirror Second at reference position measures capacitance, wherein the first reference position corresponds to the shifting as broad band light beam and movable mirror Dynamic result and the central burst of interference pattern generated, and the second reference position corresponds to and is applied by MEMS actuator To zero actuating of movable mirror.Calibration module measures capacitance and the second reference position using first at the first reference position The second of place measures capacitance to determine correcting value.
In another embodiment, MEMS device is included with the first stop part at its first end and at its second end The second stop part fixed structure and the actuator arm that is coupling between MEMS actuator and movable mirror, wherein causing Dynamic device arm has the third stop part being attached to thereon between the first stop part and the second stop part.Capacitance sensing circuit Determine that first at the first reference position of movable mirror when third stop part the first stop part of abutting measures Capacitance and second at the second reference position of movable mirror when third stop part the second stop part of abutting measure Capacitance.Calibration module measures the second measurement capacitance at capacitance and the second reference position using first at the first reference position Determine correcting value.
In another embodiment, MEMS device includes consolidating with first side and the second side opposite with first side Determine structure, wherein each in first side and second side includes multiple capacitance sensing points therebetween with known spacing. MEMS device further comprises being coupling in the actuator arm between MEMS actuator and movable mirror.Actuator arm can be It moves between the first side and second side of capacitance structure, and refers to the multiple capacitances for having known spacing therebetween.Capacitance Sensing circuit is coupled to fixed structure and actuator arm, is measured with mobile with movable mirror and is indicated capacitance sensing Point and capacitance refer between capacitance change capacitance variations.Calibration module determines correcting value using capacitance variations.
In the exemplary embodiment, capacitance sensing circuit continuously measures capacitance sensing point as movable mirror moves For corresponding capacitance between referring to capacitance to determine the zero crossing and peak position of capacitance variations, wherein zero crossing corresponds to capacitance sensing point Peak excursion and peak position between referring to capacitance correspond to capacitance sensing point and capacitance refer between smallest offset.Capacitance sensing Circuit further determine that out each in zero crossing and peak position at MEMS actuator corresponding actual capacitance.Calibration module Determine the reference position of the movable mirror at each in zero crossing and peak position, and the reality based on MEMS actuator Border capacitance and reference position determine correcting value.
In the additional examples, MEMS actuator is electrostatic actuator of the tool there are two plate, and capacitance sensing circuit Sense the capacitance present between two plates.In the exemplary embodiment, MEMS actuator is electrostatic comb drive actuator.
In a further embodiment, capacitance sensing circuit includes receiving capacitance present and generating directly proportional to capacitance Output voltage Capacitance to Voltage Converter.
The embodiment of the present invention further provides for a kind of MEMS (MEMS) interferometer system, including having by optics Ground coupling with receive with the movable mirror of reflected light, be coupled to movable mirror with cause its displacement have it is variable The MEMS actuator of capacitance, maintain the position that the capacitance of MEMS actuator is mapped to movable mirror table memory Be coupled to MEMS actuator for sense MEMS actuator capacitance present capacitance sensing circuit interferometer.MEMS is done Interferometer system further comprise for access table with based on the capacitance present of MEMS actuator come determine movable mirror work as The digital signal processor of front position and for determine MEMS actuator known to two or more of movable mirror Corresponding actual capacitance at position is with the calibration module of the correcting value of the determining current location to be applied to movable mirror.Number Word signal processor further generates the corrected current location of movable mirror using correcting value.
In the exemplary embodiment, interferometer further comprises:By optically coupled to receive incident beam and will be incident Beam splitter is into the beam splitter of the first interfering beam and the second interfering beam and by optically coupled to receive the first interfering beam And the first interfering beam is made to return towards beam splitter reflection with the stationary mirror for generating the first reflection interference light beam.It is removable anti- Mirror is penetrated by optically coupled to receive the second interfering beam and make the second interfering beam towards beam splitter reflection back to generate the Two reflection interference light beams.Detector is by optically coupled to detect as between the first reflection interference light beam and the second the reflected beams Interference result and the interference pattern that generates.In one embodiment, the displacement of movable mirror is generated equal to displacement Twice of the optical path length between the first interfering beam and the second interfering beam is poor.
Description of the drawings
Described in detail below with reference to attached drawing progress can obtain being more complete understanding of for the present invention, wherein:
Fig. 1 is the exemplary Micro Electro Mechanical system of the position according to an embodiment of the invention for being used to determine movable mirror (MEMS) block diagram of equipment;
Fig. 2 is the MEMS interferometers for illustrating the position according to an embodiment of the invention for being used to determine movable mirror The block diagram of the exemplary building block of system;
Fig. 3 is the further exemplary building block for illustrating MEMS interferometer systems according to an embodiment of the invention Block diagram;
Fig. 4 is to illustrate the special integrated electricity according to an embodiment of the invention for being used in MEMS interferometer systems The block diagram of the exemplary building block on road (ASIC);
Fig. 5 is to illustrate exemplary capacitive-voltage according to an embodiment of the invention for being used in the ASIC of Fig. 4 The circuit diagram of circuit;
Fig. 6 is the figure for the exemplary architecture for illustrating MEMS device according to an embodiment of the invention;
Fig. 7 is the figure for the exemplary architecture for illustrating MEMS interferometer systems according to an embodiment of the invention;
Fig. 8 is the figure for illustrating exemplary MEMS die encapsulation according to the present invention;
Fig. 9 illustrates the position according to an embodiment of the invention for being used to determine the movable mirror in MEMS device Illustrative methods;
Figure 10 be illustrate it is according to an embodiment of the invention for carrying out the self-alignment exemplary of speculum positioning The block diagram of MEMS interferometer systems;
Figure 11 A and Figure 11 B are the figures for illustrating capacitance sensing curve according to an embodiment of the invention;
Figure 12 A and Figure 12 B are the figures for illustrating the drift on capacitance sensing curve according to an embodiment of the invention;
Figure 13 is the reflection for the result for illustrating the drift according to an embodiment of the invention as on capacitance sensing curve The figure of the error of mirror position;
Figure 14 is to illustrate the linearity correction technology according to an embodiment of the invention for being used to carry out calibration reflector position MEMS interferometer systems exemplary building block block diagram;
Figure 15 is the figure for the interference pattern for illustrating white light source according to an embodiment of the invention;
Figure 16 is to illustrate another linearity correction according to an embodiment of the invention for being used to carry out calibration reflector position The block diagram of the exemplary building block of the MEMS interferometer systems of technology;
Figure 17 is to illustrate the gamma correction skill according to an embodiment of the invention for being used to carry out calibration reflector position The block diagram of the exemplary building block of the MEMS interferometer systems of art;
Figure 18 is the figure for the capacitance sensing gamma correction technology for illustrating Figure 17 according to an embodiment of the invention;And
Figure 19 illustrates oneself of the speculum positioning according to an embodiment of the invention in optical MEMS interferometer The illustrative methods of calibration.
Specific embodiment
According to an embodiment of the invention, a kind of self-calibration technique is provided to determine interferometer/spectrometer application etc. The position of movable mirror in MEMS (MEMS) application.The technology makes it possible to realize interferometer/spectrometer system Cost and complexity integrated and that reduce system of the system on small chip.
Referring now to Fig. 1, it is illustrated that the Exemplary MEMS devices 100 of with good grounds the embodiment of the present invention.MEMS device 100 is wrapped Include MEMS actuator 110 and movable mirror 120.MEMS actuator 110 is electrostatic actuator, as comb actuator activates Device, parallel plate actuator or other kinds of electrostatic actuator.Movable mirror 120 is coupled to MEMS actuator 110, makes MEMS actuator movement cause movable mirror 120 position displacement.
In many MEMS applications, it is necessary to know the position of removable reflective mirror 120.For example, in interferometer application, The position of removable reflective mirror 120 is used to the output of processing interferometer.The example of MEMS interferometer systems 105 is shown in fig. 2 Go out.As that can find out in fig. 2, MEMS actuator 110 and other composition portions of movable mirror 120 and interferometer 140 Part, beam splitter, stationary mirror and photoelectric detector etc. (as with reference to Fig. 7 in greater detail below described in) shape together Into MEMS interferometers 150.MEMS interferometers 150 may, for example, be Fourier transform infrared spectroscopy (FTIR) spectrometer, Michael Inferior interferometer, Mach-Zehnder interferometer or Fabry-Perot interferometer.
The optical path length that the displacement of movable mirror 120 is produced between two arms of interferometer 140 is poor, with Just the desired interference pattern at photoelectric detector is obtained.It, must in order to effectively handle the signal exported from photoelectric detector It must find out the position at least one plane of movable mirror 120.
Therefore, referring now to Fig. 1 and Fig. 2, in order to measure the position of removable reflective mirror, MEMS device 100 further include by Coupled to the capacitance sensing circuit 130 of MEMS actuator 110.Since MEMS actuator 110 is electrostatic actuator, so MEMS is caused Dynamic device 110 has the variable capacitance that can be measured by capacitance sensing circuit 130.For example, in one embodiment, capacitance sensing electricity Road 130 can be coupled to two plates of MEMS actuator 110 between detection plate capacitance (that is, measure capacitance current value, Hereinafter referred to as " capacitance present " of MEMS actuator).
Based on the capacitance present measured, it may be determined that the position of movable mirror 120.As it would be appreciated, MEMS is caused Interval (distance) between two plates of dynamic device 110 is as speculum 120 moves and changes.Since MEMS actuator 110 is quiet Electric actuator, thus interval between capacitance and two plates between two plates it is directly directly proportional (or in some cases into Inverse ratio).In this way, the capacitance between plate may be used to determine the interval, the interval and then reflector position may be used to determine.
Fig. 3 is the block diagram for the exemplary building block for illustrating MEMS interferometer systems 105 according to embodiments of the present invention. In figure 3, capacitance sensing circuit (CSC) 130 is embodied in application-specific integrated circuit (ASIC) 160.ASIC 160 further by Coupled to MEMS interferometers 150 and digital signal processor (DSP) 170.In one embodiment, DSP 170 is embodied in On ASIC 160.DSP 170 is integrated on ASIC 160 produce can be easily integrated in it is attractive in larger system Self-contained solution.However, this imposes the limitation in asic technology selection and may result in digital unit With the interference between sensitive AFE(analog front end).Therefore, in other embodiments, DSP 170 may be implemented on another ASIC Or it is embodied as the software that can be performed on general purpose personal computer.
CSC 130 in ASIC 160 is coupled to receive the capacitance sense of the MEMS actuator from MEMS interferometers 150 Survey signal 190.Capacitance present that CSC 130 measures capacitance sensing signal 190 to determine MEMS actuator and by capacitance present Value is sent to DSP 170.DSP 170 handles capacitance present value to determine position of the mobile speculum in MEMS interferometers 150 It puts.
ASIC 160 further includes to generate actuating signal 180 and actuating signal 180 is sent to MEMS interferometers 150 MEMS actuator is to control the circuit of the movement of MEMS actuator.For example, in the exemplary embodiment, ASIC 160 includes supporting The digital-analog convertor (DAC) of any arbitrary actuating profile (profile).DAC can also be very high resolution ratio with Just it reduces actuation sound and there is very high spurious-free dynamic range to ensure that undesirable mode of resonance is not energized.
In addition, ASIC 160 is further coupled to receive the optical interference pattern 195 exported from MEMS interferometers 150 simultaneously Optical interference pattern 195 is provided to DSP 170 for handling.For example, in the exemplary embodiment, MEMS interferometer systems 105 be the MEMS FTIR spectrum instrument systems using general MEMS interfaces CMOS ASIC 160.In this embodiment, MEMS interferes Instrument 150 includes photoelectric detector, stationary mirror and movable mirror.With the movement of movable mirror, Photoelectric Detection Device captures optical interference pattern 195.ASIC 160 can include amplifying signal, remove any dc offsets and provide necessary The noiselike signal of anti-aliasing filter adjusts path.Signal Regulation can be carried out last defeated to reduce in a manner of highly linear Go out any stray wave (spurious tone) in spectrum.At DSP 170, the feelings in the position for knowing movable mirror The optical wavelength of any material in optical path and spectrum print can be identified under condition to the spectrum analysis of pattern after the adjustment (spectral print)。
Referring now to Fig. 4, exemplary CRC 130 is shown.CRC 130 includes Capacitance to Voltage Converter (C/V) 200, puts Big device 210 and low-pass filter 220.C/V 200 is coupled to receive the capacitance sense for the capacitance present for indicating MEMS actuator Signal 190 is surveyed, and operates capacitance present being converted into voltage.Particularly, C/V generates two terminals with MEMS actuator Between the directly proportional voltage output of capacitance.The voltage amplification that amplifier 210 will be exported from C/V 200, and low-pass filter 220 by voltage filter to remove any spurious signal.In the exemplary embodiment, C/V 200 is that have wide gain ranging and dc Offset removes divided by supports to be superimposed upon the C/V of the very low noise of the wide capacitance range in various fixed capacities.Low noise level It is desired for CRC 130, because reflector position inaccuracy directly affects system signal noise ratio (SNR).ASIC 160 is also Low-down voltage and noise level can be shown to allow more than the resolution ratio of 18.In a further embodiment, ASIC 160 can also include capacitance calibration circuit to calibrate C/V 200.
The example of C/V 200 is shown in Fig. 5.C/V 200 includes the input terminal for receiving as measured capacitance C Son, for receiving the input terminal of reference capacitance Cref, operational amplifier 202, feedback condenser Co and envelope detector circuit 204.In exemplary operation, it is known that the ac signals of frequency (for example, 10kHz) are applied to a terminal of capacitance C, and identical The negative version of pumping signal is applied to reference capacitor Cref.The output of operational amplifier 202 is its amplitude and value (C- Cref) the ac signals of directly proportional identical frequency.
The envelope of the output of 204 detection calculations amplifier 202 of envelope detector circuit.Particularly, envelope detector circuit 204 operations are to generate the directly proportional output voltage of the amplitude (envelope) of the ac signals to being exported from operational amplifier 202.Such as Fig. 5 Shown, envelope detector circuit 204 detects the envelope of the signal Vo1 exported from operational amplifier 202 and generates and is tested with being used as The directly proportional voltage Vout of the value of the capacitance of amount.It should be understood that other circuit designs for C/V 200 are possible, And the present invention is not limited to any specific C/V circuit designs.For example, in another embodiment, C/V 200 can have multiple ends For son to sense the difference on two capacitors, wherein difference is directly proportional to reflector position.
Fig. 6 is the figure for the exemplary architecture for illustrating MEMS device 100 according to an embodiment of the invention.MEMS device 100 include ASIC 160 and MEMS device 155, such as MEMS interferometers.MEMS device 155 includes electrostatic comb drive MEMS Actuator 110 and movable mirror 120.Electrostatic comb drive MEMS actuator 110 shown in Fig. 6 is corresponding by respectively having Terminal 112 and 114 comb actuator 115 and clockwork spring (spring) 118 formation.By the way that voltage is applied at terminal 112 To comb actuator 115, potential difference is generated across actuator 110, this induction of capacitance wherein, cause driving force generation with And the restoring force from clockwork spring 118, thus cause the displacement to desired locations of movable mirror 120.The capacitance being induced CIt is variableIt can be surveyed by the port 162 and 164 being connected to terminal 112 and 114 on ASIC 160 across terminal 112 and 114 Amount.
In one embodiment, the actuating signal from ASIC 160 is by the use of time division multiplexing or frequency division multiplexing as capacitance sense Signal is surveyed to transmit by identical port (port 162).By having in single a port, there are two function (actuating and capacitance senses Survey), necessary maximum actuation voltage can be reduced, while also add the capacitance sensed.However, this may cause to sense Undesirable interaction between actuation circuit.Therefore, in other embodiments, actuating signal passes through on ASIC 160 Different port (not shown) is sent.It should be understood that the layout and feature of MEMS actuator 110 shown in Fig. 6 are only shown It is example property, and the present invention can realize with any electrostatic MEMS actuator design, either comb actuator actuator, flat Andante actuator or other kinds of electrostatic MEMS actuator.
Fig. 7 is the figure for the exemplary architecture for illustrating MEMS interferometer systems 105 according to an embodiment of the invention.MEMS Interferometer system 105 includes MEMS interferometers 150 and ASIC 160.MEMS interferometers 150 can be for example on SOI wafer Realize Fourier transform infrared (FTIR) spectrometer of the speculum to allow MEMS actuatings mobile.
MEMS interferometers 150 include MEMS actuator 110 and interferometer 140.As shown in fig. 7, interferometer 140 includes light source 300th, beam splitter 310, stationary mirror 320, photoelectric detector 330 and movable mirror 120.Light source 300 generates incident light Beam I, the incident beam are advanced through interferometer 140 until it reaches half-plane beam splitter 310.In the exemplary embodiment, divide Beam device 310 is formed in interface of the first medium (that is, silicon (Si)) between second medium (that is, air).Silicon/Air Interface point Beam device 310 is oriented to be at an angle of (for example, 45 degree) with incident beam I.Surface that can for example by defining silicon medium Photoetching generates desired angle.
When hitting half-plane beam splitter 310, incident beam I is divided into two interfering beams L1 and L2.L1 derive from into Irradiating light beam I due to reflecting the part of silicon/air half-plane beam splitter 310, and therefore have anti-equal to beam incident angle degree Firing angle degree.L2 is from incident beam I by the fractional transmission of silicon/air half-plane beam splitter 310 and with refraction angle (being determined by Snell's law) propagates in silicon at least partly.As a result, L1 is passed towards movable mirror 120 It broadcasts, and L2 is propagated towards stationary mirror 320.
Light beam L1 is reflected by movable mirror 120, therefore generates the reflected beams L3, and light beam L2 stationary mirrors 320 Reflection, therefore generate the reflected beams L4.As shown in fig. 7, both light beam L3 and L4 are respectively from 120 and 320 reflection of speculum The identical optical path (in the opposite direction) that L1 and L2 is respectively adopted afterwards is reflected towards half-plane beam splitter 310.Cause This, in the embodiment for being used as Fourier transformation (FT) spectrometer in spectrometer/interferometer, an interferometer arm is by light beam L1/ L3 is formed and including beam splitter 310 and movable mirror 120, and another interferometer arm is formed by light beam L2/L4 and including solid Determine speculum 320.
Interference pattern L5 is formed by the reflected beams L3 and L4 interfered in beam splitter 310.Interference pattern L5 passes through detection Device 330 detects.The output of detector 330 is input to ASIC 160 via terminal 166.In one embodiment, detector 330 by micromachined in the substrate including being assembled (for example, realizing Photoelectric Detection by etching the top surface of substrate Device can be disposed within opening) or by adulterating (for example, to realize P-I-N diodes) or passing through partially metallised (example Such as, to realize metal-semiconductor-metal MSM photodetector) and monolithic is realized in substrate photoelectric detector.
Or as shown in fig. 7, movable mirror 120 can utilize SOI electrostatic MEMSs actuator 110 and move.With in Fig. 6 Equally, electrostatic MEMS actuator 110 is shown as being formed by comb actuator 115 and clockwork spring 118.Voltage can be via terminal 114 Comb actuator 114 is applied to, thus induction of the capacitance across terminal 112 and 114 and causes movable mirror 120 To the displacement of the desired locations of the reflection for light beam L1.It is substantially equal in this way, can obtain twice of mirror displacements Optical path length between light beam L3 and L4 is poor (OPD).
In addition, the capacitance across terminal 112 and 114 can be measured by ASIC 160 with true via port 162 and 164 Surely the position of removable reflective mirror 120.Based on the movable mirror position determined and the output of detector 330, can produce Interference pattern 340 (such as DSP 170 by being shown in Fig. 3) is given birth to identify the wavelength of any material in optical path and spectrum Print.
Movable mirror 120 in Fig. 7 is shown as being positioned between two optical paths (L1/L3 and L2/L4) Zero path difference at.However, in other embodiments, in order to remove the resulting phase noise as capacitive sensing technology And error, movable mirror 120 can be positioned at the distance δ behind zero path position, and movable mirror 120 Zero path position be may move through so that being measured in both the positive side of zero path position and negative side.In this case, Source 300 is that broad band source (that is, white light source) and negative side and positive side can be equal or different.At DSP 170 (being shown in Fig. 3), The multiple change Fourier transformation of interference pattern 340 can be carried out with any phase error in compensatory reflex mirror position.In another implementation In example, both the positive side of substitution record interference pattern and negative side, the sub-fraction on negative (left side) side of interference pattern can be adopted With and pass through DSP be used for extracting correct signal and remove in the phase noise and error generated by capacitive sensing technology one A bit.
In one embodiment, speculum 120 and 320 is metallic mirror, wherein using selective metallization (such as Projection print plate is used during metallization step) to protect beam splitter.In another embodiment, it is anti-using nonmetallic vertical Prague Mirror is penetrated to obtain the spectrometer of reduced dimension area.Bragg mirror can be realized using deep reaction ion etching (DRIE), Thus continuous vertical silicon/Air Interface is generated.In addition, Bragg mirror can be designed to wide range reflex response fill When simple reflector or with wavelength selectivity response, depending on application.
Although silicon/Air Interface is described for beam splitter 310 herein, it is to provide half-wave planar splitter other Medium can be used to realize the present invention.For example, in a further exemplary embodiment, micromachined or assembling glass half The other materials of plane or heat resistant glass (Pyrex) etc. can be used for replacing silicon to allow the wider spectrum window of operation Mouthful.In addition, the other materials of liquid or gas with various etc. can be used for replacing air to provide modification half-plane beam splitting circle The degree of freedom of the reflectance factor in face.
Fig. 8 is the figure for illustrating exemplary MEMS die encapsulation 400 according to the present invention.Come by using capacitance sensing true Determine the position of movable mirror, MEMS interferometers 150 can be integrated in identical MEMS die envelope together with 160 chips of ASIC It fills on 400, thus reduces the size, cost and complexity of MEMS system.
Fig. 9 illustrates the position according to an embodiment of the invention for being used to determine the movable mirror in MEMS device Illustrative methods 500.Method starts from 510, wherein providing the electrostatic with variable capacitance coupled to movable mirror MEMS actuator.At 520, make movable mirror displacement using MEMS actuator.Hereafter, at 530, sensing MEMS actuatings The capacitance present of device, and at 540, the position of movable mirror is determined based on the capacitance present of MEMS actuator.
Referring now to Figure 10, in some embodiments, capacitance sensing circuit may be attributed to stress, temperature, humidity, electricity The normal drift and other reasons of sub- building block and by performance drift.Such drift effect in capacitance sensing circuit To the accuracy of the position of movable mirror, this directly influences spectrometer/interferometric operation.Therefore, as shown in Figure 10, school Quasi-mode block 600 can be included in MEMS interferometers 105 to calibrate the determining capacitance sensing for optical path difference modulation Circuit (CSC) 130.In one embodiment, calibration module 600 is by the algorithms performed of DSP 170 and can be stored in Such as in memory 620.In another embodiment, calibration module 600 is included in the ASIC of CSC 130 or additional In ASIC.
As discussed above, movable mirror 120 introduces optical path difference in a path of interferometer 140, Cause to export interference pattern, can be extracted from the output interference pattern by indicated Fourier transformation in as the following formula 1 and 2 Spectrum.
Accurate spectrum in order to obtain needs to be attributed to the accurate of the optical path difference (OPD) of movable mirror displacement It measures.The accuracy of OPD is initially calibrated with CSC 130 as discussed above with as mobile mirror 120 is moved through The gamut of movement and the movement of capacitively sensing MEMS actuator 150.The capacitance (capacitance data 640) finally measured is reflected Corresponding OPD (position data 650) is mapped to, and in the table 630 that can be then stored in memory 620.
It for example, can be by specific known wavelength λ0Light beam 102 inject in MEMS interferometers 105 to be directed in the production line Each spectrum samples are calibrated CSC 130 once.As that can find out in Figure 11 A and Figure 11 B, capacitance-OPD relationships are to use The continuous peak position of two of obtained interference pattern represents λ0OPD the fact and map that in the capacitance variations measured with It generates capacitance sensing curve 720 and determines, it is as follows:
(Δ x) is equal to λ for the distance between continuous zero crossing 710 of two of which0/2。
Referring again to Figure 10, the capacitance sensing curve 720 of Figure 11 B can be used for filling C (capacitance data 640)-x (positions Data 650) relationship look-up table 620, the look-up table then can be used for during the subsequent operation of MEMS interferometers 105 really Determine the position of movable mirror 120.For example, during the subsequent operation of MEMS interferometers 105, CSC 130 can be passed through The capacitance across MEMS actuator 150 is measured, and the capacitance measured can be provided to DSP 170 with by accessing memory Table 630 in 620 determines the position of movable mirror 120.
In addition, as shown in Figure 10, in order to compensate for any drift in CSC 130, calibration module 600 may further determine that The correcting value 610 is simultaneously provided to DSP 170 by correcting value 610.DSP 170 can use correcting value 610 and predetermined anti- Mirror position (being searched based on the capacitance measured and table 630 provided by CSC 130) is penetrated to determine corrected reflector position. Output based on corrected movable mirror position and interferometer 140, DSP 170 can then generate interference pattern to know Wavelength and the spectrum print of any material in other optical path.In addition, DSP 170 and/or the ASIC containing CSC 130 can give birth to Into actuating signal to control the movement of MEMS actuator 150 so that speculum 120 is moved to desired locations using correcting value 610.
In the exemplary embodiment, calibration module 600 passes through two or more known bits in movable mirror 120 The place of putting determines the actual capacitance of MEMS actuator 150 to determine correcting value 610.For example, calibration module 600 can by two or more The actually measured capacitance of the MEMS actuator 150 of multiple known positions each capacitance corresponding in table 630 is compared, To calculate the corresponding error between the actual capacitance measured and the correspondence capacitance in table 630.Calibration module 600 can then make It is inferred to corrected capacitance sensing curve, and based on corrected with initial capacitance sensing curve and the error calculated Capacitance sensing curve and initial capacitance sensing curve between difference determine the correcting value to be applied to reflector position 610。
For example, as illustrated in figs. 12 a and 12b, the drift of initial capacitance value (being stored in the table 630 of Figure 10) can be with inclined Shift error (Bd) and/or gain error (Ad) form occur.As that can find out in figs. 12 a and 12b, it is stored in table Initial value provide with A0The B at zero OPD of gain0Capacitance.In the subsequent operation of MEMS interferometers, hair The drift in CSC is given birth to so that zero OPD corresponds to BdCapacitance and gain at this time be Ad.As further as shown in figure 13, In the presence of such drift, lead to the OPD values of mistake (with x using initial value mapping capacitance sensing-OPD relationshipsIt is practicalIt compares xError), this can lead to wavelength error and spectral drift.Therefore, it is necessary to the additional calibrations of initial capacitance value to correct OPD values.It is attached Calibration is added to generate correcting value as described above, which can include offset error amount and/or gain error amount.
Figure 14 to Figure 18 illustrates the exemplary alignment technique to drift about in view of capacitance sensing, so that use can be realized In the calibration of self―sustaining (self-sustained) that the optical path of MEMS interferometers is modulated.In one embodiment, such as Shown in Figure 14 and Figure 15, wideband light source 800 is used to self calibration MEMS interferometers.In this example it is assumed that capacitance measurement pair The error of position is linear.Therefore it may only be necessary to two capacitance measurements at known mirror position are closed to correct for C-x The drift error of system.
Wideband light source 800 has by the spectrum S (v) in injection interferometer 140.The obtained white light shown in Figure 15 is done Relating to figure can express as follows, for from v1To v2Wave-number range in work MEMS interferometers:
Wherein
Wv=v1-v2(formula 6)
S (x)=Fourier Transform [S (v)] (formula 7)
As that can find out in fig.15, reflector position and source light at the central burst 830 of white light interference figure Spectral shape is unrelated, this more to be immune to source fluctuation and drift dependent on the position.Therefore, as shown in figure 14, CSC 130 The capacitance of MEMS actuator 150, and the capacitance that will be measured can be continuously measured in the case where obtaining white light interference figure It is provided to calibration module 600.From the obtained interference pattern provided by interferometer 140, calibration module 600 can be determined when shifting Dynamic speculum 120 is in the capacitance of measurement when corresponding at the burst position 820 of central burst 830 and should Burst position 820 maps to zero OPD, and zero OPD can be considered for self-alignment first reference position.
In addition, CSC 130 can be measured when MEMS actuator is idle (applies that is, not activating to mobile mirror 120) capacitance of the MEMS actuator 150 when, and the free time is measured into capacitance and is provided to calibration module 600.It is obvious that work as MEMS When actuator 150 is idle, mobile mirror 120 is in known resting position 810, which can be considered as self-alignment Second reference position.Use the measurement capacitance at each in reference position and the initial capacitance being stored in table 630 And positional value, calibration module 600 can determine by DSP 170 to apply to capacitance sense during subsequent MEMS interferometric operations Survey the correcting value 610 of curve (being stored in the value in table 630).Therefore, any capacitance sensing linear drift in subsequent interference pattern It can be compensated using correcting value 610.
Figure 16 illustrates another linearity correction skill to 930c self calibration MEMS interferometers using actuator stop part 930a Art.In the embodiment being shown in FIG. 16, MEMS actuator 150 is coupled to mobile mirror 120 via actuator arm 900. Fixed structure 920 surrounds actuator arm 900 so that actuator arm 900 is between the opposite side of fixed structure 920.Gu Structure 920 is determined with the first stop part 930a at its first end and the second stop part 930c at its second end.It causes Dynamic device arm 900 has the first stop part 930a and the second stop part 930c that are positioned in fixed structure 920 being attached to thereon Between third stop part 930b.
MEMS actuator 150 is configured to that speculum 120 is made in the first stop part 930a of fixed structure 920 with second to stop It is moved in the range of extending between block piece 930c.In addition, when the third stop part 930b on actuator arm 920 abuts the first backstop During part 930a and the second stop part 930c, the corresponding position (displacement) of movable mirror 120 is known.Therefore, CSC 130 It can measure as the first stop part 930a of the third stop part 930b abutting fixed structures 920 of actuator arm 900 The capacitance of MEMS actuator 150, the capacitance correspond to the first reference position for self-alignment movable mirror 120.Together Sample, CSC 130 can be measured when the third stop part 930b of actuator arm 900 abuts the second stop part of fixed structure 920 The capacitance of MEMS actuator 150 during 930c, the capacitance correspond to the second benchmark for self-alignment movable mirror 120 Position.Initial storage capacitance out of the measurement at two reference positions capacitance and table 630, calibration module 600 can determine It treats to be applied to the school of capacitance sensing curve (being stored in the value in table 620) by DSP 170 during subsequent MEMS interferometric operations Positive quantity 610.
In another embodiment, the linear technique illustrated in Figure 14 and Figure 16 combination can be provided for when there are non- The gamma correction in MEMS interferometers during linearity error.Each in technology in Figure 14 and Figure 16 uses two measurements It puts to determine error.Therefore, two technical combinations being provided can be used for correcting four measurement points for fourth order error.
The error (fourth order or higher) of even more high-order can come school using the capacitive sensing technology illustrated in Figure 17 Just.In fig. 17, fixed capacitance structure 1000 is arranged on the either side of actuator arm 900 so that 900 quilt of actuator arm It is located between the opposite side of fixed structure 1000.Every side of fixed structure includes multiple with known spacing therebetween Capacitance sensing point 1010.In addition, actuator arm 900, which includes multiple capacitances with known spacing therebetween, refers to 1020.
Actuator arm 900 is coupled to the first port (port A) of CSC, and fixed structure 1000 is coupled to the of CSC Two-port netwerk (port B), so that CSC can measure instruction as MEMS actuator 150 moves movable mirror 120 Capacitance sensing point 1010 and capacitance refer to the capacitance variations of the change of the capacitance between 1020.Capacitance variations can be then by calibrating Module is using determining correcting value.
For example, CSC can continuously measure capacitance sensing point 1010 and capacitance as movable mirror 120 moves Refer to the corresponding capacitance between 1020, to determine the zero crossing and peak position of capacitance variations.As should be understood, zero crossing corresponds to electricity Appearance sensing points 1010 and capacitance refer to the peak excursion between 1020, and peak position refers to corresponding to capacitance sensing point 1010 with capacitance Smallest offset between 1020.
In addition, it is such as described above in conjunction with Fig. 6 and Fig. 7, it is caused at each in zero crossing and peak position across MEMS The corresponding actual capacitance of dynamic device 150 can measure at the port C and D of CSC.Calibration module can be then measured in zero crossing With the reference position of the movable mirror 120 at each in peak position, and the reality based on MEMS actuator and reference position Border capacitance determines correcting value.
Therefore, the capacitance sensing collimation technique of Figure 17 makes it possible to obtain N number of datum mark, wherein capacitance zero crossing or capacitance Spacing between peak position corresponds to benchmark fixed cycle xPeriod, as that can find out in figure 18.By sensing mobile mirror arm Capacitance between 900 and fixed structure 1000 changes, and can come school using the capacitance zero crossing and capacitance peak position shown in Figure 18 The displacement of quasi-reflection mirror and result calibration OPD.
Figure 19 illustrates oneself of the speculum positioning according to an embodiment of the invention in optical MEMS interferometer The illustrative methods 1900 of calibration.Method starts from 1910, wherein carrying out the initial calibration of reflector position to fill MEMS causes The table of the initial value of dynamic device capacitance and corresponding reflector position.At 1920, in two or more known bits of speculum It puts place and measures MEMS actuator capacitance again.Then, it at 1930, determines to wait to apply based on the capacitance measured of known position Add to the correcting value of the initial value stored in table.
As the skilled person will recognize, innovative concepts described in the present invention can be in the wide model of application Enclose interior modifications and variations.Therefore, the range of patented subject matter should not necessarily be limited by any one in discussed particular exemplary introduction, But it is limited by appended claims.

Claims (23)

1. a kind of MEMS (MEMS) equipment, including:
Movable mirror;
MEMS actuator is coupled to the movable mirror to cause its displacement, and the MEMS actuator has variable Capacitance;
Memory maintains the table for the position that the capacitance of the MEMS actuator is mapped to the movable mirror;
Capacitance sensing circuit is coupled to the MEMS actuator, for sensing the capacitance present of the MEMS actuator;
Digital signal processor, it is described to be determined based on the capacitance present of the MEMS actuator for accessing the table The current location of movable mirror;And
Calibration module, for by determine the MEMS actuator known to two or more of the movable mirror Corresponding actual capacitance at position to determine the correcting value of the current location to be applied to the movable mirror, is come It corrects the drift of the capacitance present of the MEMS actuator and therefore corrects the capacitance present and the removable reflection Relationship between the current location of mirror;
Wherein described digital signal processor further generates the corrected of the movable mirror using the correcting value Current location,
Wherein described MEMS device further comprises:
Wideband light source, for generating broad band light beam;
Interferometer, including:
Beam splitter, by optically coupled with receive the broad band light beam and by the broad band light beam be beamed into the first interfering beam and Second interfering beam;
Stationary mirror, by optically coupled to receive first interfering beam and make first interfering beam described in Beam splitter reflection returns to generate the first reflection interference light beam;
The movable mirror, by optically coupled to receive second interfering beam and make the second interfering beam court To the beam splitter reflection back to generate the second reflection interference light beam, the displacement of the movable mirror is dry described first It is poor equal to twice of optical path length of the displacement to relate to generation between light beam and second interfering beam;And
Detector, by optically coupled to detect as between the first reflection interference light beam and second the reflected beams The result of interference and the interference pattern generated;
Wherein described capacitance sensing circuit determines that first of the first known position in the movable mirror measures electricity Hold, first known location corresponds to be generated as the result of the movement of the broad band light beam and the movable mirror Interference pattern central burst;
Wherein described capacitance sensing circuit determines that second of the second known position in the movable mirror measures electricity Hold, second known location, which corresponds to, to be applied by the MEMS actuator to zero actuating of the movable mirror;And
Wherein described calibration module measures capacitance and second known bits using described the first of first known position Described the second of the place of putting measures capacitance to determine the correcting value;
Wherein described first known location is different from second known location.
2. MEMS device according to claim 1, wherein the MEMS actuator is electrostatic actuator of the tool there are two plate, The capacitance sensing circuit senses the capacitance present between described two plates.
3. MEMS device according to claim 2, wherein the MEMS actuator is electrostatic comb drive actuator.
4. MEMS device according to claim 1, wherein the capacitance sensing circuit includes receiving the current electricity Hold and generate the Capacitance to Voltage Converter of the output voltage directly proportional to the capacitance.
5. MEMS device according to claim 1, wherein:
The table represents capacitance sensing curve;
The calibration module will be in the actual capacitance of the MEMS actuator of the two or more known positions Each capacitance corresponding in the table is compared, with calculate the actual capacitance measured with it is corresponding in the table Capacitance between corresponding error;
The calibration module is inferred to corrected capacitance sense using the capacitance sensing curve and the error calculated Survey curve;And
The calibration module determines the institute to be applied to the current location using the corrected capacitance sensing curve State correcting value.
6. MEMS device according to claim 1, wherein the interferometer is Fourier transform infrared (FTIR) spectrometer.
7. a kind of MEMS (MEMS) equipment, including:
Movable mirror;
MEMS actuator is coupled to the movable mirror to cause its displacement, and the MEMS actuator has variable Capacitance;
Memory maintains the table for the position that the capacitance of the MEMS actuator is mapped to the movable mirror;
Capacitance sensing circuit is coupled to the MEMS actuator, for sensing the capacitance present of the MEMS actuator;
Digital signal processor, it is described to be determined based on the capacitance present of the MEMS actuator for accessing the table The current location of movable mirror;And
Calibration module, for by determine the MEMS actuator known to two or more of the movable mirror Corresponding actual capacitance at position to determine the correcting value of the current location to be applied to the movable mirror, is come It corrects the drift of the capacitance present of the MEMS actuator and therefore corrects the capacitance present and the removable reflection Relationship between the current location of mirror;
Wherein described digital signal processor further generates the corrected of the movable mirror using the correcting value Current location;And
Wherein described MEMS device further comprises:
Fixed structure has the first stop part at its first end and the second stop part at its second end;
Actuator arm is coupling between the MEMS actuator and the movable mirror, and the actuator arm has attached Third stop part thereon is connected to, the third stop part is between first stop part and second stop part;
Wherein described capacitance sensing circuit determine when the third stop part abut first stop part when it is described can The first of first known position of mobile mirror measures capacitance;
Wherein described capacitance sensing circuit determine when the third stop part abut second stop part when it is described can The second of second known position of mobile mirror measures capacitance;And
Wherein described calibration module measures capacitance and second known bits using described the first of first known position Described the second of the place of putting measures capacitance to determine the correcting value.
8. MEMS device according to claim 7, further comprises:
Wideband light source, for generating broad band light beam;
Interferometer, including:
Beam splitter, by optically coupled with receive the broad band light beam and by the broad band light beam be beamed into the first interfering beam and Second interfering beam;
Stationary mirror, by optically coupled to receive first interfering beam and make first interfering beam described in Beam splitter reflection returns to generate the first reflection interference light beam;
The movable mirror, by optically coupled to receive second interfering beam and make the second interfering beam court To the beam splitter reflection back to generate the second reflection interference light beam, the displacement of the movable mirror is dry described first It is poor equal to twice of optical path length of the displacement to relate to generation between light beam and second interfering beam;And
Detector, by optically coupled to detect as between the first reflection interference light beam and second the reflected beams The result of interference and the interference pattern generated;
Wherein described capacitance sensing circuit is determined to measure electricity in the third of the third known position of the movable mirror Hold, the third known location corresponds to be generated as the result of the movement of the broad band light beam and the movable mirror Interference pattern central burst;
Wherein described capacitance sensing circuit determines that the 4th of the 4th known position in the movable mirror measures electricity Hold, the 4th known location, which corresponds to, to be applied by the MEMS actuator to zero actuating of the movable mirror;And
Wherein described calibration module measures capacitance, second known location using described the first of first known position Described the second of place measures capacitance, the third of the third known position measures capacitance, the 4th known position The 4th measurement capacitance determine the correcting value;
Wherein described third known location is different from the 4th known location.
9. MEMS device according to claim 7, wherein the MEMS actuator is electrostatic actuator of the tool there are two plate, The capacitance sensing circuit senses the capacitance present between described two plates.
10. MEMS device according to claim 8, wherein the MEMS actuator is electrostatic comb drive actuator.
11. MEMS device according to claim 7, wherein the capacitance sensing circuit includes receiving the current electricity Hold and generate the Capacitance to Voltage Converter of the output voltage directly proportional to the capacitance.
12. MEMS device according to claim 7, further comprises:
Light source, for generating the inputs light beam with known wavelength;
Interferometer, including:
Beam splitter, by optically coupled with receive the inputs light beam and by the inputs light beam be beamed into the first interfering beam and Second interfering beam;
Stationary mirror, by optically coupled to receive first interfering beam and make first interfering beam described in Beam splitter reflection returns to generate the first reflection interference light beam;
The movable mirror, by optically coupled to receive second interfering beam and make the second interfering beam court To the beam splitter reflection back to generate the second reflection interference light beam, the displacement of the movable mirror is dry described first It is poor equal to twice of optical path length of the displacement to relate to generation between light beam and second interfering beam;And
Detector, by optically coupled to detect as between the first reflection interference light beam and second the reflected beams The result of interference and the interference pattern generated;
Wherein as the movable mirror is moved through at least two zero crossings of the interference pattern, the capacitance sensing Circuit measuring goes out capacitance variations;And
Wherein described digital signal processor is based on the capacitance variations and the interference pattern fills the table.
13. MEMS device according to claim 7, wherein:
The table represents capacitance sensing curve;
The calibration module will be in the actual capacitance of the MEMS actuator of the two or more known positions Each capacitance corresponding in the table is compared, with calculate the actual capacitance measured with it is corresponding in the table Capacitance between corresponding error;
The calibration module is inferred to corrected capacitance sense using the capacitance sensing curve and the error calculated Survey curve;And
The calibration module determines the institute to be applied to the current location using the corrected capacitance sensing curve State correcting value.
14. the MEMS device according to claim 6 or 12, wherein the interferometer is Fourier transform infrared (FTIR) light Spectrometer.
15. a kind of MEMS (MEMS) equipment, including:
Movable mirror;
MEMS actuator is coupled to the movable mirror to cause its displacement, and the MEMS actuator has variable Capacitance;
Memory maintains the table for the position that the capacitance of the MEMS actuator is mapped to the movable mirror;
Capacitance sensing circuit is coupled to the MEMS actuator, for sensing the capacitance present of the MEMS actuator;
Digital signal processor, it is described to be determined based on the capacitance present of the MEMS actuator for accessing the table The current location of movable mirror;And
Calibration module, for by determine the MEMS actuator known to two or more of the movable mirror Corresponding actual capacitance at position to determine the correcting value of the current location to be applied to the movable mirror, is come It corrects the drift of the capacitance present of the MEMS actuator and therefore corrects the capacitance present and the removable reflection Relationship between the current location of mirror;
Wherein described digital signal processor further generates the corrected of the movable mirror using the correcting value Current location;And
Wherein described MEMS device further comprises:
Fixed structure has first side and the second side opposite with the first side, the first side and described the Each in two side faces includes multiple capacitance sensing points therebetween with known spacing;
Actuator arm is coupling between the MEMS actuator and the movable mirror, and can be in the capacitive junctions It is moved between the first side and the second side of structure, the actuator arm has the multiple electricity for having known spacing therebetween Appearance refers to;And
The capacitance sensing circuit is coupled to the fixed structure and the actuator arm, with the movable mirror It is mobile and measure indicate the capacitance sensing point and the capacitance refer between capacitance change capacitance variations, wherein described Peak position in capacitance variations corresponds to the physical base of the actuator arm on schedule, and in the physical base, there are the capacitances at place on schedule Sensing points and the capacitance refer between smallest offset, in the two or more known locations of the movable mirror At least one first known location determined at the physical standard position of the actuator arm.
16. MEMS device according to claim 15, wherein the capacitance sensing circuit is with the movable mirror It is mobile and continuously measure the capacitance sensing point refer to the capacitance between corresponding capacitance to further determine that the capacitance The zero crossing of variation, the zero crossing corresponds to the additional physical standard position of the actuator arm, in the additional object Reason reference position at there are the capacitance sensing point and the capacitance refer between peak excursion, the institute of the movable mirror State the additional physics of the second known location of at least one of two or more known locations in the actuator arm It is determined at reference position.
17. MEMS device according to claim 16, wherein:
The capacitance sensing circuit further determine that out each in the zero crossing and the peak position at the MEMS The corresponding actual capacitance of actuator;And
The actual capacitance and the movable mirror of the calibration module based on the MEMS actuator it is described two Or more known location determine the correcting value.
18. MEMS device according to claim 15, wherein the MEMS actuator is electrostatically actuated of the tool there are two plate Device, the capacitance sensing circuit sense the capacitance present between described two plates.
19. MEMS device according to claim 18, wherein the MEMS actuator is electrostatic comb drive actuator.
20. MEMS device according to claim 15, wherein the capacitance sensing circuit is including described current for receiving Capacitance and the Capacitance to Voltage Converter for generating the output voltage directly proportional to the capacitance.
21. MEMS device according to claim 15, further comprises:
Light source, for generating the inputs light beam with known wavelength;
Interferometer, including:
Beam splitter, by optically coupled with receive the inputs light beam and by the inputs light beam be beamed into the first interfering beam and Second interfering beam;
Stationary mirror, by optically coupled to receive first interfering beam and make first interfering beam described in Beam splitter reflection returns to generate the first reflection interference light beam;
The movable mirror, by optically coupled to receive second interfering beam and make the second interfering beam court To the beam splitter reflection back to generate the second reflection interference light beam, the displacement of the movable mirror is dry described first It is poor equal to twice of optical path length of the displacement to relate to generation between light beam and second interfering beam;And
Detector, by optically coupled to detect as between the first reflection interference light beam and second the reflected beams The result of interference and the interference pattern generated;
Wherein as the movable mirror is moved through at least two zero crossings of the interference pattern, the capacitance sensing Circuit measuring goes out capacitance variations;And
Wherein described digital signal processor is based on the capacitance variations and the interference pattern fills the table.
22. MEMS device according to claim 15, wherein:
The table represents capacitance sensing curve;
The calibration module will be in the actual capacitance of the MEMS actuator of the two or more known positions Each capacitance corresponding in the table is compared, with calculate the actual capacitance measured with it is corresponding in the table Capacitance between corresponding error;
The calibration module is inferred to corrected capacitance sense using the capacitance sensing curve and the error calculated Survey curve;And
The calibration module determines the institute to be applied to the current location using the corrected capacitance sensing curve State correcting value.
23. MEMS device according to claim 21, wherein the interferometer is Fourier transform infrared (FTIR) spectrum Instrument.
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