CN2599525Y - Micro-displacement real time noninterence measurer - Google Patents
Micro-displacement real time noninterence measurer Download PDFInfo
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- CN2599525Y CN2599525Y CNU03228828XU CN03228828U CN2599525Y CN 2599525 Y CN2599525 Y CN 2599525Y CN U03228828X U CNU03228828X U CN U03228828XU CN 03228828 U CN03228828 U CN 03228828U CN 2599525 Y CN2599525 Y CN 2599525Y
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- light source
- light
- beam splitter
- displacement real
- micrometric displacement
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Abstract
The utility model relates to an interferometer designed for real-time micro displacement measurement. The utility model comprises a first light source provided with a DC power supply, and a first lens, a polarized beam splitter, a beam splitter, a reference tablet and the tested object are arranged successively on the same optical axis in the traveling direction of the light beam from the light source. A receiving element is arranged in the direction of the reflecting beam f#-[2] of the beam splitter, and the receiving element is connected to a singlechip and then connected to a display; a second lens and a modulated light source are successively arranged in the traveling direction of the reflecting beam f#-[1] of the polarized beam splitter; the modulated light source is provided with a drive connected to a second DC power supply and a phase shifter, and the other end of phase shifter is connected to a sine signal generator; and the sine signal generator is connected to the singlechip through a controller. The light beams from the light source and the modulated light source are polarized light beams with polarization planes perpendicular with each other. The utility model has the advantages of that signals can be collected, processed and displayed in a real-time manner, the operation is simple and the tested data are reliable.
Description
Technical field:
The utility model relates to micro-displacement interferometry apparatus, particularly relates to the semiconductor laser micrometric displacement real-time interferometer that uses sinusoidal phase modulation.
Background technology:
Because the temperature stability of semiconductor laser (being designated hereinafter simply as LD) wavelength is solved preferably, the semiconductor laser interference instrument is is researched and developed widely.LD except that volume is little, power-saving, price low, an outstanding advantage is that wavelength-modulated is easy.This makes the light heterodyne technology that can improve measuring accuracy can realize by the injection current of direct modulation LD simply in the semiconductor laser interference instrument.The interferometer that is used for measuring vibrations that proposes such as Suzuki Xiaochang (Takamasa Suzuki) Mr. of Japanese Nigata (Niigata) university, (Takamasa Suzuki, Takao Okada, Osami Sasaki, and Takeo Maruyama, " Real-time vibration measurement usinga feedback type of laser diode interferometer with an optical fiber ", Opt.Eng., 1997,36 (9), 2496-2502.) this interferometer as shown in Figure 1.Is parallel beam as the light beam that light source 1 sends by first lens, 2 collimations with semiconductor laser, and the folded light beam f that is reflected by beam splitter 3 shines on the reference mirror 4, sees through the transmitted light beam t of beam splitter 3
3Shine on the testee 5, the interference signal that the folded light beam of reference mirror 4, testee 5 produces is converted to electric signal by receiving element 6, carries out data processing by signal processing circuit 7, is shown by oscillograph 8.Driver 9 is connected with sinusoidal signal generator 11 with first direct supply 10 respectively.Inject a sinusoidal current signal to light source 1 and make light source 1 wavelength sinusoidal variations, thereby obtain the interference signal of sinusoidal phase modulation.Behind the treated circuit of interference signal 7, but nano-precision is measured the micro-displacement of testee.
Behind the semiconductor laser injection current as light source 1, its intensity and wavelength are respectively:
g(t)＝β
1[i
o+Δi(t)]， (1)
λ(t)＝λ
o+β
2Δi(t)， (2)
i
oBe respectively the direct current and the AC compounent of drive current, β with Δ i (t)
1, β
2Be proportionality constant, λ.For corresponding to DC component i
oCentre wavelength.AC compounent
Δi(t)＝acos(ω
ct+θ) (3)
Receiving element 6 detected interference signals are:
I(t)＝I
o(t)+s
o(t)cos[zcos(ω
ct+θ)+α
o+α(t)] (4)
I wherein
o(t) and s
o(t) be the modulated time dependent function that produces of output intensity owing to light source 1, Z is the amplitude of interference signal phase modulation (PM), α
o=2 π r
o/ λ
o, α (t)=4 π r (t)/λ
o, r
oBe testee 5 optical path difference when static, r (t) is a micro-displacement to be measured.The treated circuit of interference signal 7 backs are by (4) formula (Osami Sasaki Kazuhide Takahashi, and TakamasaSuzuki, " Sinusoidal phase modulating laser diode interferometerwith a feedbacr control system to eliminate external disturbance; " Opt.Eng., 1990,29 (12), 1511-1515.) try to achieve α (t), and then try to achieve micro-displacement r (t).
Because the light intensity g (t) of light source 1 is modulated, make I
o(t) and s
o(t) change in time, cause measuring error.For eliminating this error, assistant assistant wood is repaiied, and Mr. adopts the method for software to come the variation of compensatory light 1 output intensity, this compensation is obtaining interference signal after realize during data processing, only is rough compensation, and needs revise software at any time according to the variation of external condition.This interferometer needs the user according to the variation of external condition fixed software at any time, and this will cause the deuce to pay to correct measurement; And this method need be carried out Fourier transform and inverse transformation to interference signal, needs the certain calculation time, therefore also is not suitable for real-time control.
The utility model content:
The technical problems to be solved in the utility model is to overcome the defective of above-mentioned prior art, a kind of micrometric displacement real-time interferometer is provided, to solve the compensation problem of the intensity variation that the direct modulation light wavelength causes, make the easy to operate of microdisplacement measurement, and reliable test result.
Technical solution of the present utility model is as follows:
A kind of micrometric displacement real-time interferometer is characterized in that its formation comprises:
One light source has first direct supply, is equipped with first lens, polarization beam apparatus, beam splitter, reference plate and testee successively with optical axis ground on this light emitted light beam working direction;
Folded light beam f at this beam splitter
2Direction is equipped with receiving element, and single-chip microcomputer is sent in its output, connects display again;
Folded light beam f at this polarization beam apparatus
1On the direction of advancing, be equipped with second lens and modulated light source successively; This modulated light source has driver, and this driver connects second direct supply and phase shifter, another termination sinusoidal signal generator of this phase shifter, and this sinusoidal signal generator via controller connects single-chip microcomputer.
The light beam that light source and modulated light source are sent is the orthogonal polarized light of plane of polarization.
Described light source and modulated light source all are semiconductor lasers.
Described receiving element is photodiode or photoelectric cell.
Described polarization beam apparatus is a polarization splitting prism.
Described beam splitter is incident light can be divided into the element of two-beam by 1: 1 light intensity, and as Amici prism, the parallel flat of light film is analysed in the one side plating.
Described reference plate is a parallel flat, and it is by the one side plating anti-reflection film of beam splitter, and nearly object simultaneously plates and increases anti-film, and its reflectivity is 0.08～0.73, and transmittance is 0.27～0.92.
Advantage of the present utility model has:
1), since interference signal finish by single-chip microcomputer, can make total system finish collection, processing and the demonstration of signal accurately in real time, and enlarge the measurement range of system effectively.
2), improved measuring accuracy.In the prior art, during the wavelength of direct modulation light 1, the output intensity of light source 1 changes in time, has influenced the intensity of interference signal.Because displacement is obtained according to this intensity, so measuring error has been introduced in the variation of output intensity.The utility model contains modulated light source 15, utilizes the wavelength of photo-thermal effect modulated light source 1, and the output intensity of light source 1 does not change in time, has avoided this measuring error, has improved measuring accuracy.
3), the variation of the output intensity of prior art is to adopt the software approach compensation.This compensation is after obtaining interference signal, realizes during data processing, only is rough compensation, has residual error, and needs at any time software to be revised according to the variation of external condition.The utility model has been avoided this compensation problem.
4), with regard to the interferometer of prior art direct modulation light 1 wavelength, the user must according to the variation of external condition at any time fixed software change with the compensation light intensity, this correctly uses this instrument to bring difficulty for the user.Interferometer of the present utility model uses easy and simple to handle.
Description of drawings:
Fig. 1 is the interferometer structure block diagram of prior art direct modulation light 1 wavelength;
Fig. 2 is the utility model micrometric displacement real time interferometer example structure block diagram.
Embodiment:
See also Fig. 2, Fig. 2 is the structured flowchart of the utility model micrometric displacement real-time interferometer embodiment, and as seen from the figure, the utility model micrometric displacement real-time interferometer comprises the device, testee 5, single-chip microcomputer 7, the oscillograph 8 that place in the casing 19.In casing 19, have on the emission light beam working direction of light source 1 of first direct supply 10 and be equipped with first lens 2 successively with optical axis ground, polarization beam apparatus 17, beam splitter 3, reference plate 18 and testee 5.Folded light beam f at beam splitter 3
2On be equipped with output and be connected to the receiving element 6 that single-chip microcomputer 7 is connected.Folded light beam f at polarization beam apparatus 17
1On the direction of advancing, be equipped with second lens 16 and modulated light source 15 successively.Modulated light source 15 has driver 9, and driver 9 is connected with second direct supply 14 and phase shifter 13.Phase shifter 13 links to each other with controller 12 through sinusoidal signal generator 11, and controller 12 is connected on the single-chip microcomputer 7.
Above said light source 1 and modulated light source 15 all be that to adopt wavelength be the semiconductor laser of 785nm.
Said receiving element 6 is photodiodes.
Said polarization beam apparatus 17 is polarization splitting prisms.
Said single-chip microcomputer is an Aduc812 data acquisition system (DAS) chip.
The course of work of the present utility model roughly is: the LD as light source 1 is driven by first direct supply 10, makes the light intensity of light source 1 not change in time, and the wavelength of light source 1 carries out the photo-thermal modulation by modulated light source 15 sinusoidal light waves.The light that light source 1 sends sees through the transmitted light beam t of polarization beam apparatus 17 and beam splitter 3 by first lens, 2 collimations
1Shine on the reference plate 18, see through the transmitted light beam t of reference plate 18
2Shine on the testee 5, the interference signal that reference plate 18 and testee 5 beam reflected produce is converted to electric signal by receiving element 6, sends into single-chip microcomputer 7 and handles, and the result is presented at oscillograph 8.The signal of sinusoidal signal generator 11 enters the driver 9 of modulated light source 15 behind phase shifter 13, the light that modulated light source 15 is sent, is focused on the light source 1 by first lens 2 after polarization beam apparatus 17 reflections by second lens, 16 collimations.Light source 1 is vertical mutually with the polarisation of light direction that modulated light source 15 is sent, polarization beam apparatus 17 makes the light transmission of light source 1 and does not reflex on the modulated light source 15, the light of modulated light source 15 is incided on the light source 1, and wherein the segment beam that is reflected by light source 1 can not see through polarization beam apparatus 17.Sinusoidal signal generator 11 adds the output intensity sinusoidal variations that sinusoidal signal makes modulated light source 15 by phase shifter 13 to driver 9, after this light intensity shines on the light source 1, because photo-thermal effect, the corresponding sinusoidal variations of the junction temperature of light source 1 makes the wavelength of interferometer light source 1 by sinusoidal variations.The phase place of the interference signal that receiving element 6 receives is by Sine Modulated.Because the injection current of light source 1 is a direct current, the output intensity of light source 1 does not change in time, so the interference signal that receives of receiving element 6
I(t)＝I
o+S
o?cos[z?cos(ω
ct+θ)+α
o+α(t)] (5)
Wherein, I
oWith S
oBe respectively in the amplitude that relates to signal DC component and AC compounent, z is the amplitude of interference signal phase modulation (PM), α
o=2 π r
o/ λ
o, α (t)=4 π r (t)/λ
o, r
oBe testee 5 optical path difference when static.R (t) is a micro-displacement to be measured.Interference signal is (Osami Sasaki and Hirokazu Okazaki after single-chip microcomputer adopts continuous phase (phase-mwrapping) to handle, " Sinusoidal phase modulating interferometer using optical fibers fordisplacement measurement; " Appl.Opt.1988,27 (19), 4139-4142.) try to achieve α (t)
r(t)＝mπ/4+λ
oα(t)/4πo (6)
Wherein m is an integer, and the measuring accuracy of α (t) reaches 0.01rad and is easier to realize.Adopting wavelength commonly used is the LD of 785nm, and the resolution of displacement is 0.62nm.If the measuring accuracy of α is brought up to 0.001rad, then resolution is brought up to 0.062nm.
Because of the variation in time of output intensity of light source 1, the I in the formula (5)
o, S
oBe constant, thereby light intensity changes influence to measuring when fundamentally having solved modulation wavelength.
Claims (6)
1, a kind of micrometric displacement real-time interferometer is characterized in that its formation comprises:
Light source (1) has first direct supply (10), is equipped with first lens (2), polarization beam apparatus (17), beam splitter (3), reference plate (18) and testee (5) successively with optical axis ground on this light source (1) emission light beam working direction;
Folded light beam f in this beam splitter (3)
2Direction is equipped with receiving element (6), and single-chip microcomputer (7) is sent in its output, connects display (8) again;
Folded light beam f in this polarization beam apparatus (17)
1On the direction of advancing, be equipped with second lens (16) and modulated light source (15) successively; This modulated light source (15) has driver (9), this driver (9) connects second direct supply (14) and phase shifter (13), another termination sinusoidal signal generator (11) of this phase shifter (13), this sinusoidal signal generator (11) via controller (12) connects single-chip microcomputer (7);
The light beam that light source (1) and modulated light source (15) are sent is the orthogonal polarized light of plane of polarization.
2, micrometric displacement real-time interferometer according to claim 1 is characterized in that described light source (1) and modulated light source (15) all are semiconductor lasers.
3, micrometric displacement real-time interferometer according to claim 1 is characterized in that described receiving element (6) is photodiode or photoelectric cell.
4, micrometric displacement real-time interferometer according to claim 1 is characterized in that described polarization beam apparatus (17) is a polarization splitting prism.
5, micrometric displacement real-time interferometer according to claim 1 is characterized in that described beam splitter (3) is incident light can be divided into the element of two-beam by 1: 1 light intensity, and as Amici prism, the parallel flat of light film is analysed in the one side plating.
6, micrometric displacement real-time interferometer according to claim 1, it is characterized in that described reference plate (8) is a parallel flat, it is by the one side plating anti-reflection film of beam splitter (3), and the plating of nearly object (5) one side increases anti-film, its reflectivity is 0.08～0.73, and transmittance is 0.27～0.92.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU03228828XU CN2599525Y (en) | 2003-02-14 | 2003-02-14 | Micro-displacement real time noninterence measurer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU03228828XU CN2599525Y (en) | 2003-02-14 | 2003-02-14 | Micro-displacement real time noninterence measurer |
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| Publication Number | Publication Date |
|---|---|
| CN2599525Y true CN2599525Y (en) | 2004-01-14 |
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|---|---|---|---|
| CNU03228828XU Expired - Fee Related CN2599525Y (en) | 2003-02-14 | 2003-02-14 | Micro-displacement real time noninterence measurer |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1304815C (en) * | 2005-07-12 | 2007-03-14 | 陈昌浩 | Micro-displacement measuring system and based on semiconductor laser-charge coupler |
| CN100547344C (en) * | 2007-02-07 | 2009-10-07 | 中国科学院上海光学精密机械研究所 | The sinusoidal phase modulation interferometer of real-time surface measurements pattern |
| CN101141200B (en) * | 2007-10-15 | 2010-08-04 | 哈尔滨工业大学 | Multi-frequency phase modulation based multi-wavelength source generating apparatus |
| CN103105134A (en) * | 2013-01-08 | 2013-05-15 | 中国航空工业集团公司北京长城计量测试技术研究所 | Interferometry measurement system of micro-displacement based on cat eye reflecting principle |
| CN109253698A (en) * | 2018-09-21 | 2019-01-22 | 湖北工业大学 | A kind of displacement sensor |
-
2003
- 2003-02-14 CN CNU03228828XU patent/CN2599525Y/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1304815C (en) * | 2005-07-12 | 2007-03-14 | 陈昌浩 | Micro-displacement measuring system and based on semiconductor laser-charge coupler |
| CN100547344C (en) * | 2007-02-07 | 2009-10-07 | 中国科学院上海光学精密机械研究所 | The sinusoidal phase modulation interferometer of real-time surface measurements pattern |
| CN101141200B (en) * | 2007-10-15 | 2010-08-04 | 哈尔滨工业大学 | Multi-frequency phase modulation based multi-wavelength source generating apparatus |
| CN103105134A (en) * | 2013-01-08 | 2013-05-15 | 中国航空工业集团公司北京长城计量测试技术研究所 | Interferometry measurement system of micro-displacement based on cat eye reflecting principle |
| CN103105134B (en) * | 2013-01-08 | 2015-05-27 | 中国航空工业集团公司北京长城计量测试技术研究所 | Interferometry measurement system of micro-displacement based on cat eye reflecting principle |
| CN109253698A (en) * | 2018-09-21 | 2019-01-22 | 湖北工业大学 | A kind of displacement sensor |
| CN109253698B (en) * | 2018-09-21 | 2021-07-13 | 湖北工业大学 | Displacement sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |