CN2577236Y - Nano-precision displacement and vibration interference measuring apparatus - Google Patents
Nano-precision displacement and vibration interference measuring apparatus Download PDFInfo
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- CN2577236Y CN2577236Y CN 02260947 CN02260947U CN2577236Y CN 2577236 Y CN2577236 Y CN 2577236Y CN 02260947 CN02260947 CN 02260947 CN 02260947 U CN02260947 U CN 02260947U CN 2577236 Y CN2577236 Y CN 2577236Y
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Abstract
The utility model relates to a nanon-precision displacement and vibration interferometric device, which comprises a light source that is provided with a first driving power supply and a temperature controller, a collimation light source for adjusting the collimation of optical paths, and an excitation light source for vibrating the objects to be measured, wherein, the three light sources have unequal wavelengths. The whole optical paths for transmitting light beams are carried out in optical fibers, wave-combining elements and a fiber coupler. Two photoelectric conversion element only responds to the wave bands of the light beams emitted by the corresponding light source, and does not respond to the light beams emitted by the collimation light source and the excitation light source. A phase control set for controlling initial phase is connected between the first driving power supply and an analog-to-digital converter. Compared with the prior art, the utility model has the advantages of compact structure, small size, higher antijamming capability, no error from wavelength shift and high measuring precision.
Description
Technical field:
The utility model relates to nano-precision displacement and vibration interferometric measuring means, specially refers to the micrometric displacement (less than the mm magnitude) and little vibration (less than the mm magnitude) interferometric measuring means that use the sinusoidal phase modulation interferometry
Background technology:
In the semiconductor laser interference instrument, the light heterodyne technology that is used for improving measuring accuracy can be realized by the injection current of directly modulated laser (hereinafter to be referred as LD) simply.By the modulation injection current, be easy to realize the phase modulation (PM) of interference signal, thereby realize the measurement of parameter degree of precision such as displacement, distance, face shape.But its output intensity is simultaneously modulated when the injection current of modulation LD, and this causes certain measuring errors.For reducing the modulated measuring error that causes of output intensity as the LD of light source, inventor king Xiang Chao etc. provides a kind of optical frequency photo-thermal Modulating Diode Laser interferometer (referring to technology [1] Wang Xiangchao formerly, Wang Xuefeng, Qian Feng, " with the micro-displacement interferometry apparatus of semiconductor laser, " Chinese patent application number: 99113908.9).In this interferometer, adopted photothermal technique modulated light source wavelength, make that the modulated amplitude of output intensity is very little, improved measuring accuracy greatly.Regrettably this interferometer uses the bulk optics system, and volume is big, antijamming capability is relatively poor relatively; The measuring beam diameter is big and can not be used for the displacement of the small object of measurement size; Simultaneously, the use of two light sources causes cost to increase, and adjusts difficulty and impracticable; And do not consider the temperature control measure of laser instrument, the laser wavelength drift that temperature variation causes will cause measuring error.
Summary of the invention:
The utility model is the deficiency that overcomes above-mentioned technology formerly, and a kind of nano-precision displacement and vibration interferometric measuring means are provided.The utility model is introduced the collimated light source of visible light, two photo-electric conversion elements and phase controller.To overcome and adjust difficulty, wave length shift, the problem that antijamming capability is relatively poor in the above-mentioned technology formerly.
Nano-precision displacement of the present utility model and vibration interferometric measuring means, comprise that the light source 3 that has first driving power 2 and temperature controller 4 passes through first section optical fiber 301 by light source 3 emitted light beams, isolator 16 and second section optical fiber 302, inject by the first second port b that closes ripple element 7, after penetrating from first the 3rd port c that closes ripple element 7, again by the 3rd section optical fiber 303, the first port P1 by coupling mechanism 8, equally after the 3rd port P3 ejaculation of coupling mechanism 8, inject by the second first port d that closes ripple element 15 through the 4th section optical fiber 304, after penetrating from second the 3rd port f that closes ripple element 15, through after the 5th section optical fiber 305 and the collimating apparatus 17, permeation parts reflecting element 18 is mapped on the testee 19 again; Pass through the 6th section optical fiber 601 by collimated light source 6 visible light emitted that have second driving power 5, from the first first port a incident of closing ripple element 7, after closing the 3rd port c outgoing of ripple element 7 from first, inject through the first port P1 of the 3rd section optical fiber 303 again by coupling mechanism 8, equally after the 3rd port P3 ejaculation of coupling mechanism 8, inject by the second first port d that closes ripple element 15 through the 4th section optical fiber 304, after penetrating from second the 3rd port f that closes ripple element 15, through after the 5th section optical fiber 305 and the collimating apparatus 17, permeation parts reflecting element 18 is mapped on the testee 19 again; Exciting light source 14 emitted light beams that have the 3rd driving power 13 are by the 7th section optical fiber 1401, by the second second port e incident of closing ripple element 15, after penetrating from second the 3rd port f that closes ripple element 15, through after the 5th section optical fiber 305 and the collimating apparatus 17, permeation parts reflecting element 18 is mapped on the testee 19 again; Light beam by the second port P2 outgoing of coupling mechanism 8 is mapped on first photo-electric conversion element 9 by the 8th section optical fiber 801; Light beam by the 4th port P4 outgoing of coupling mechanism 8 is mapped on second photo-electric conversion element 12 by the 9th section optical fiber 802; The output of first photo-electric conversion element 9 and second photo-electric conversion element 12 is connected on the computing machine 11 by analog to digital converter 10 simultaneously; Between first driving power 2 and analog to digital converter 10, be connected with phase controller 1.As shown in Figure 1.
Nano-precision displacement of the present utility model and vibration interferometric measuring means.Shown in Figure 1 as above-mentioned structure.The light source 3 emission light beams that have first driving power 2 and temperature controller 4 link to each other with isolator 16 by first section optical fiber 301.The second port b that the output terminal of isolator 16 and first closes ripple element 7 links to each other.The first first port a that closes ripple element 7 is connected to the collimated light source 6 that has second driving power 5 by the 6th section optical fiber 601.The first port P1 that first the 3rd port c that closes ripple element 7 passes through the 3rd section optical fiber 303 and coupling mechanism 8 links to each other.The 3rd port P3 of coupling mechanism 8 is connected to the second first port d that closes ripple element 15 by the 4th section optical fiber 304.The second second port e that closes ripple element 15 is connected to the exciting light source 14 that has the 3rd driving power 13 by the 7th section optical fiber 1401.Second the 3rd port f that closes ripple element 15 is connected to collimating apparatus 17 by the 5th section optical fiber 305.Partial reflection element 18, testee 19 are placed with optical axis with collimating apparatus 17.The second port P2 of coupling mechanism 8, the 4th port P4 are connected to first photo-electric conversion element 9 and second photo-electric conversion element 12 by the 8th section optical fiber 801 and the 9th section optical fiber 802 respectively.First photo-electric conversion element 9 all links to each other with the analog to digital converter 10 that is connected with computing machine 11 with second photo-electric conversion element 12.Phase controller 1 links to each other with analog to digital converter 10 with first driving power 2.
Above said light source 3, collimated light source 6, exciting light source 14 all are semiconductor laser (also claim laser diode, abbreviate LD as), the only visible light of collimated light source 6 emissions wherein.Light source 3 is unequal with the wavelength of collimated light source 6 and exciting light source 14 emission of lasering beam.
Said first driving power 2 provides direct current, sinusoidal ac signal to light source 3.
Said second driving power 5 provides direct current signal to collimated light source 6.
Said the 3rd driving power 13 provides direct current and AC signal to exciting light source 14.
Said first closes ripple element 7, second, and to close ripple element 15 be to be used for realizing that light beam closes the fiber optic component on road, can be fiber coupler or optical fiber wave multiplexer (multiplexer).Coupling mechanism 8 is a fiber coupler.
Said collimating apparatus 17 is meant that its emergent light is the optical element of directional light.
Said partial reflection element 18 is meant and can makes a part of transmittance, the element that a part of light reflects back.Wherein one side does not reflect, or reflectivity very low (reflectivity R＜0.005), or reflected light can not return and be mapped in the optical fiber, and the reflected light of another side can reflect back in the optical fiber simultaneously, and its reflectivity satisfies (0.05＜R＜0.45).
Said first, second photo-electric conversion element 9 and 12 response wave length are photodiodes at the wave band of light source 3 emission laser, or photoelectric cell etc.
The initial phase of said phase controller 1 control interference signal.
The temperature of said temperature controller 4 control light sources 3 only changes the temperature of light source 3 in small range.
As above-mentioned structure shown in Figure 1, the light that light source 3 sends incides in the isolator 16 by first section optical fiber 301.The emergent light of isolator 16 incides the first second port b that closes ripple element 7 by second section optical fiber 302, and from first the 3rd port c outgoing of closing ripple element 7.The light beam that returns in the light path can not pass through isolator 16.Incide the first port P1 of coupling mechanism 8 by the 3rd section optical fiber 303 from first light that closes the 3rd port c outgoing of ripple element 7.Wherein the light by the 4th port P4 outgoing of coupling mechanism 8 incides second photo-electric conversion element 12 by the 9th section optical fiber 802.Incide the second first port d that closes ripple element 15 by the light of the 3rd port P3 outgoing of coupling mechanism 8 by the 4th section optical fiber 304,, incide on the collimating apparatus 17 by the 5th section optical fiber 305 again from second the 3rd port f outgoing of closing ripple element 15.Incide on the partial reflection element 18 through outgoing beam behind the collimation of collimating apparatus 17, the light beam of permeation parts reflecting element 18 incides on the testee 19.Have light that the exciting light source 14 of the 3rd driving power 13 sends and incide the second second port e that closes ripple element 15 by the 7th section optical fiber 1401, after closing the 3rd port f outgoing of ripple element 15 from second, incide on the collimating apparatus 17 by the 5th section optical fiber 305 again, shine on the testee 19 through the emergent light permeation parts reflecting element 18 behind collimating apparatus 17 collimations, excitation testee 19 produces vibration.By 18 reflections of testee 19 and partial reflection element return the light that comes produce interfere after, after closing ripple element 15 and enter coupling mechanism 8 by collimating apparatus 17 and second again from the 3rd port P3 of coupling mechanism 8, the second port P2 outgoing from coupling mechanism 8, convert electric signal by the 8th section optical fiber 801 to by first photo-electric conversion element 9, be input in the analog to digital converter 10.The electric signal of first photo-electric conversion element 9 and 12 outputs of second photo-electric conversion element is input to through analog to digital converter 10 simultaneously and carries out in the computing machine 11 showing its measurement result after the data processing.The light that the above-mentioned collimated light source 6 that has second driving power 5 sends is visible light, by the 6th section optical fiber 601 by the first first port a incident of closing ripple element 7, after closing the 3rd port c outgoing of ripple element 7 from first, again by of the first port P1 incident of the 3rd section optical fiber 303 by coupling mechanism 8, after the 3rd port P3 outgoing of coupling mechanism 8, equally again by the 4th section optical fiber 304 by the second first port d incident of closing ripple element 15, from second the 3rd port f outgoing of closing ripple element 15, inciding on the collimating apparatus 17 by the 5th section optical fiber 305.Incide partial reflection element 18 behind collimating apparatus 17 collimations, the transmitted light of partial reflection element 18 incides on the testee 19.The light beam that is returned by 19 reflections of partial reflection element 18 and testee is in the second and the 4th port P2 of coupling mechanism 8, the collimating status that P4 observes its light path.Collimated light source 6 visible light emitted are in order to adjust the collimation of light path.The initial phase of the interference signal that phase controller 1 control computer 11 collects is 0 or π.Temperature controller 4 is used for the stable temperature that has the light source 3 of first driving power 2.The spectral characteristic of first photo-electric conversion element 9 and second photo-electric conversion element 12 satisfies only can convert the light of light source 3 to electric signal, and can not convert the light of exciting light source 14 and collimated light source 6 to electric signal.
Concrete description is: behind light source 3 injection currents, its wavelength is:
λ (t)=λ
0+ β
1Δ i (t), (1) Δ i (t) is the AC compounent of drive current, β
1Be proportionality constant, λ
0Be centre wavelength corresponding to DC component.AC compounent
Δi(t)＝acos(ω
ct+θ)。(2) ω
cBe the angular frequency of the sinusoidal phase modulation of light source 3, t is the time, and θ is the initial phase of light source 3 sinusoidal phase modulation, and a is the amplitude of AC compounent.
First photo-electric conversion element, 9 detected interference signals are:
S (t)=I
B(t)+I
M(t) cos[zcos (ω
cT+ θ)+α
0+ α (t)], (3) are I wherein
B(t), I
M(t) be respectively the background intensity and the modulate intensity of interference signal.Z is the phase modulation (PM) degree of depth of interference signal, α
0=2 π r
0/ λ
0, α (t)=4 π r (t)/λ
0, r
0Be testee 19 optical path difference when static, r (t) is micro-displacement or microvibration to be measured.
Light source 3 intensity variation that second photo-electric conversion element 12 detects are:
I (t)=β
2{ i
0+ α cos[ω
c(t-τ)+θ] }, (4) are β wherein
2Be proportionality constant, i
0Be the DC component of light source 3 drive currents, τ prolonged for the light time from light source 3 to second photo-electric conversion elements 12.Same on the both sides of formula (3) divided by (4), can obtain removing the interference signal of light source 3 light-intensity variations influence:
S (t)=C+Ccos[zcos (ω
cT+ θ)+α
0+ α (t)]. (5) wherein C are constant.Following formula is carried out Fourier transform (technology [2] Osami Sasaki and HirokazuOkazaki formerly, " Sinusoidal phase modulating interferometer using optical fibers fordisplacement measurement; " Appl.Opt.1988,27 (19), 4139-4142.) try to achieve α (t)
r(t)＝λ
0α(t)/4π。(6) measuring accuracy of α (t) reaches 0.01rad and is easier to realize.If light source 3 adopts wavelength X
0Be the LD of 1310nm, the resolution of displacement is 1.04nm.If the measuring accuracy of α is brought up to 0.001rad, then resolution is brought up to 0.1nm.
The utility model is compared with technology formerly, has outstanding feature:
＜1〉compares with technology [1] formerly, nano-precision displacement of the present utility model adopts two photo-electric conversion elements 9 and 12 to carry out luminosity compensation with the vibration interferometric measuring means, eliminate the intensity modulation in the interference signal, save modulated light source, reduced the adjustment difficulty.
＜2〉compare with technology [1] formerly, nano-precision displacement of the present utility model all is in optical fibre device inside such as optical fiber, fiber couplers with the light beam transmission passage of vibration interferometric measuring means, bulk optics devices such as lens in the technology formerly, polarization beam apparatus, beam splitter have been substituted, and two photo-electric conversion elements are arranged, not only make little, in light weight, the compact conformation of measuring instrument volume of the present utility model, and antijamming capability strengthens.
＜3〉compare with technology [1] formerly, nano-precision displacement of the present utility model and vibration interferometric measuring means, the diameter of measuring hot spot has reduced an order of magnitude, can be used to measure the displacement and the vibration of small items.
＜4〉compare with technology [1] formerly, nano-precision displacement of the present utility model and vibration interferometric measuring means, light source 3 has temperature controller 4, and light source 3 has been carried out temperature control, temperature can be ignored the influence of wavelength, eliminated the measuring error of bringing by wave length shift.
＜5〉compare with technology [1] formerly, nano-precision displacement of the present utility model and vibration interferometric measuring means, exciting light source 14 is arranged, the function that not only has Displacement Measurement, and has an excitation and vibration testing function, can encourage the object that is similar to the microcantilever beam, make its vibration, and utilize vibration measuring function nano precision ground to measure its vibration simultaneously.
＜6〉compare with technology [1] formerly, nano-precision displacement of the present utility model and vibration interferometric measuring means, the collimated light source 6 that visible emitting is arranged, have the reflected light that makes testee reflected light and reference mirror and interfere laggard function of going in the optical fiber, can utilize collimated light source 6 visible light emitted irradiation testee, the adjustment interferometer is become easily and intuitively.
＜7〉compare with technology [1] formerly, nano-precision displacement of the present utility model and vibration interferometric measuring means, between first driving power 2 and analog to digital converter 10, be connected with phase controller 1, therefore when gathering interference signal, have phase control function, can make the initial phase θ of the interference signal that collects by phase controller 1 is 0 or π, and the measuring accuracy of this moment is the highest.
＜8〉compare with technology [1] formerly, nano-precision displacement of the present utility model and vibration interferometric measuring means adopted two photo-electric conversion elements 9 and 12 spectral characteristic satisfy can convert the light of light source 3 to electric signal, and can not convert the light of exciting light source 14 and collimated light source 6 to electric signal.Therefore, the wavelength of having eliminated in the measurement result from its exciting light source 14 and collimated light source 6 disturbs.
Description of drawings:
Fig. 1 is nano-precision displacement of the present utility model and the structural representation that vibrates interferometric measuring means.
Embodiment:
Structure as shown in Figure 1.Wherein collimated light source 6 adopts wavelength 660nm, the semiconductor laser of peak power output 30mW.Exciting light source 14 adopts wavelength 785nm, the semiconductor laser of peak power output 50mW.It is the distributed feedback semiconductor laser (DFB-LD) of 1305nm that light source 3 adopts wavelength.First photo-electric conversion element 9 and second photo-electric conversion element 12 are photodiode, and its wavelength response is at 1.3 mu m wavebands.First closes that ripple element 7, second closes ripple element 15 and coupling mechanism 8 is fiber coupler.The splitting ratio of coupling mechanism 8 is 1: 1.The diameter of the outgoing beam of collimating apparatus 17 is 0.2 millimeter.The reflectivity of partial reflection element 18 is 27%.When beginning to measure, at first open light source 3, and make the temperature stabilization of light source 3 with temperature controller 4.Emergent light with collimated light source 6 shines testee 19 earlier, and the observation optical path collimation is opened light source 3 again, by regulating testee 19 its reflected light and the reflected light of partial reflection element 18 is interfered.By regulating the output that the 3rd driving power 13 changes exciting light source 14, shine testee 19, excitation testee 19 makes it vibration.Make θ=0 of interference signal by control phase controller 1, the amplitude of the sinusoidal ac signal by regulating first driving power 2 makes the phase modulation (PM) depth z=2.34rad of interference signal.Try to achieve the displacement r (t) of testee 19.According to formula (6), r (t)=103.85 α (t) nm (unit of α is a radian).
Claims (3)
1. nano-precision displacement and vibration interferometric measuring means, comprise the light source (3) that has first driving power (2) and be connected to analog to digital converter (10) on the computing machine (11), it is characterized in that by the light source that has temperature controller (4) (3) emitted light beams by first section optical fiber (301), isolator (16) and second section optical fiber (302), inject by first second port (b) that closes ripple element (7), after penetrating from first the 3rd port (c) that closes ripple element (7), equally again by the 3rd section optical fiber (303), first port (P1) by coupling mechanism (8) is injected, after the 3rd port (P3) ejaculation of coupling mechanism (8), inject by second first port (d) that closes ripple element (15) through the 4th section optical fiber (304), after penetrating from second the 3rd port (f) that closes ripple element (15), through after the 5th section optical fiber (305) and the collimating apparatus (17), permeation parts reflecting element (18) is mapped on the testee (19) again; Pass through the 6th section optical fiber (601) by the collimated light source that has second driving power (5) (6) visible light emitted, from first first port (a) incident of closing ripple element (7), after closing the 3rd port (c) outgoing of ripple element (7) from first, inject by first port (P1) of coupling mechanism (8) through the 3rd section optical fiber (303) again, after the 3rd port (P3) ejaculation of coupling mechanism (8), inject by second first port (d) that closes ripple element (15) through the 4th section optical fiber (304), after penetrating from second the 3rd port (f) that closes ripple element (15), through after the 5th section optical fiber (305) and the collimating apparatus (17), permeation parts reflecting element (18) is mapped on the testee (19) again; Exciting light source (14) emitted light beams that has the 3rd driving power (13) is by the 7th section optical fiber (1401), by second second port (e) incident of closing ripple element (15), after penetrating from second the 3rd port (f) that closes ripple element (15), through after the 5th section optical fiber (305) and the collimating apparatus (17), permeation parts reflecting element (18) is mapped on the testee (19) again; Light beam by second port (P2) outgoing of coupling mechanism (8) is mapped on first photo-electric conversion element (9) by the 8th section optical fiber (801); Light beam by the 4th port (P4) outgoing of coupling mechanism (8) is mapped on second photo-electric conversion element (12) by the 9th section optical fiber (802); The output of first photo-electric conversion element (9) and second photo-electric conversion element (12) is connected on the analog to digital converter (10) simultaneously; Between first driving power (2) and analog to digital converter (10), be connected with phase controller (1).
2. nano-precision displacement according to claim 1 and vibration interferometric measuring means, it is characterized in that said light source (3), collimated light source (6) and exciting light source (14) all are semiconductor lasers, the wavelength of the wavelength of light source (3) emission light beam and collimated light source (6) and exciting light source (14) generation light beam is unequal, and wherein collimated light source (6) is a visible light source.
3. nano-precision displacement according to claim 1 and 2 and vibration interferometric measuring means is characterized in that the wave band of the response wave band of said first photo-electric conversion element (9) and second photo-electric conversion element (12) at light source (3) emission light beam.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02260947 CN2577236Y (en) | 2002-10-24 | 2002-10-24 | Nano-precision displacement and vibration interference measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02260947 CN2577236Y (en) | 2002-10-24 | 2002-10-24 | Nano-precision displacement and vibration interference measuring apparatus |
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| Publication Number | Publication Date |
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| CN2577236Y true CN2577236Y (en) | 2003-10-01 |
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ID=33727871
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| CN 02260947 Expired - Fee Related CN2577236Y (en) | 2002-10-24 | 2002-10-24 | Nano-precision displacement and vibration interference measuring apparatus |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1333230C (en) * | 2005-01-26 | 2007-08-22 | 清华大学 | Laser feedback nano displaycement measuring device |
| CN100373146C (en) * | 2005-10-21 | 2008-03-05 | 中国科学院上海光学精密机械研究所 | Precision detecting method for random vibration of isolation mounting |
-
2002
- 2002-10-24 CN CN 02260947 patent/CN2577236Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1333230C (en) * | 2005-01-26 | 2007-08-22 | 清华大学 | Laser feedback nano displaycement measuring device |
| CN100373146C (en) * | 2005-10-21 | 2008-03-05 | 中国科学院上海光学精密机械研究所 | Precision detecting method for random vibration of isolation mounting |
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| CF01 | Termination of patent right due to non-payment of annual fee |