CN1036292C - Two-frequency laser collimation measuring method and interferometer - Google Patents
Two-frequency laser collimation measuring method and interferometer Download PDFInfo
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- CN1036292C CN1036292C CN92110543A CN92110543A CN1036292C CN 1036292 C CN1036292 C CN 1036292C CN 92110543 A CN92110543 A CN 92110543A CN 92110543 A CN92110543 A CN 92110543A CN 1036292 C CN1036292 C CN 1036292C
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- 238000000034 method Methods 0.000 title claims abstract description 11
- 238000005259 measurement Methods 0.000 claims abstract description 30
- 238000006073 displacement reaction Methods 0.000 claims abstract description 6
- 238000000691 measurement method Methods 0.000 claims abstract description 6
- 230000010287 polarization Effects 0.000 claims description 6
- 239000010453 quartz Substances 0.000 claims description 6
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- 230000007935 neutral effect Effects 0.000 description 2
- 208000035126 Facies Diseases 0.000 description 1
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Abstract
The present invention puts forward a new double-frequency laser collimation and measurement method which belongs to the technical field of double-frequency laser precision measurement. The method is characterized in that a double-frequency laser beam is projected into a first birefringence light splitting element to be divided into two beams of light with a small included angle; the two beams of light become a parallel light beam after passing through a second birefringence light splitting element; the parallel light beam returns according to the original path after being reflected by a reflection body, and is received by a photoelectric receiver to be used as a measurement signal. A phase meter compares a double-frequency laser reference signal with the measurement signal to obtain a displacement value. The present invention is good for overcoming the influence of air interference, and is capable of not only carrying out continuous measurement but also carrying out intermittent measurement. The present invention has wide application prospect in the precision measurement of actual engineering.
Description
The invention belongs to the Technology of Precision Measurement field, particularly adopt precision measurement method and the surveying instrument thereof of dual-frequency laser interference technique in large scale, on a large scale.
At present, along with updating and improve of measuring technique, to measuring instrument in large scale, the application power of high-acruracy survey aspect requires more and more higher, the double-frequency zeeman laser interferometer adopts the heterodyne measurement technology, the interference of having avoided direct current measurement to be vulnerable to, have in use that range is big, precision is high, good stability, the characteristics that antijamming capability is strong.Utilize two-frequency laser interferometer, be equipped with suitable measurement annex and form measuring system, can realize to length, linearity, flatness, angle, etc. carry out precision measurement.But in actual applications, during particularly long distance is measured on a large scale, for the shake and the drift of collimated light beam, the influence of air disturbance does not also solve well etc. problem, in addition, this class surveying instrument generally can only be used as continuous coverage, does not fit into the occasion of discontinuous measurement.For example, U.S. Hewlett-Packard Corporation adopts the Zeeman interferometer to be equipped with suitable annex can to carry out the measurement of linearity.Its straight line degree measurement annex as shown in Figure 1, by quarter wave plate, neutral Amici prism 2, wollaston prism 3, plane mirror 4 constitutes.Wherein, wollaston prism or plane mirror and measured object are fixed together.Its measuring principle is as follows: produced by zeeman laser and revolve two kinds of polarized lights about a branch of, become a branch of two kinds of linearly polarized lights that contain quadrature through quarter wave plate, through neutral Amici prism 1, arrive wollaston prism 2 and be divided into two bundles that certain angle is arranged, its frequency is respectively f
1And f
2, directive plane mirror 3.Plane mirror 3 constitutes two level crossings of certain angle and forms by linking together, its angle matches with the angle that wollaston prism separates light beam, on two-beam difference normal incidence to two level crossing, and return the Wollaston mirror by former direction, because vertical moving arranged between wollaston prism and the level crossing, make two light beams form optical path difference, produce the frequency change of beat signal, and receive by photelectric receiver through Amici prism.Because on two different reflecting bodys of two-beam directive that such scheme requires to separate from wollaston prism, only in this way, light beam could direction on request return, therefore, the distance that separate at the center of two-beam must be greater than spot diameter, two-beam is separated fully, otherwise can cause the noise of measuring-signal, even can't work.In actual use, when measurement reach 3 meters far away apart from the time, it is far away that the two-beam spacing is approximately 80mm.Yet prove that according to theory and practice when the distance of two-beam surpassed 10mm, the characteristics of the disturbance that they are subjected to were to add up independently, can not cancel out each other, its optical path difference will change with atmospheric disturbance.The atmospheric disturbance problem is the problem that this measurement scheme is difficult to overcome.In addition, this measuring method adopts digital subtractor demodulation two-frequency signal, promptly adopts frequency counting to draw displacement.The mistake meter appears in (as wollaston prism is shifted out light path, when surveying right alignment prism is moved on to another hole from a hole, surface measurements is discontinuous etc.) counter when measuring-signal disappears for a certain reason, can not reappear former counting.Thereby this technical scheme can only carry out continuous coverage, can not intermittently measure.This is the another weak point of this scheme, and this also is a unsolved major issue in the current practical application.
The objective of the invention is to overcome the weak point of above-mentioned prior art, propose a kind of new double-frequency laser alignment measurement method and device thereof, eliminate the influence of air turbulence, improve measuring accuracy and measurement stability measuring.Not only can carry out continuous coverage, also can intermittently measure.
Basic composition of the present invention comprises two-frequency laser, spectroscope, and two groups of birefringence beam splitters, reflecting body, photelectric receiver, the detecting signal unit each several part, its alignment measurement method comprises following each step:
1, sends a branch of light that contains two kinds of frequencies, two kinds of polarization directions by said two-frequency laser;
2, this light beam separated into two parts light behind said spectroscope, first's light is received by first photelectric receiver; Become reference signal;
3, after second portion light was injected first group of birefringence beam splitter, this had the light of two kinds of frequencies, two kinds of polarization directions to be divided into to accompany a low-angle two-beam; Again through becoming two parallel bundle polarized lights behind second group of birefringence beam splitter;
4, directive one reflecting body simultaneously of the two-beam in the third step, and return by former road, behind said two groups of birefringence beam splitters, receive again by second photelectric receiver, become measuring-signal;
5, said detecting signal unit is made of analyzer and phasometer, and said reference signal is sent into phasometer with measuring-signal through analyzer and carried out bit comparison mutually, obtains the displacement of measured object.
In the such scheme, two groups of birefringence beam splitters can adopt two group optically-active wedges, or two groups of wollaston prisms, and when selecting wollaston prism for use, the double-frequency laser bundle is a linearly polarized light beam.Single reflecting body can be selected right-angle prism for use, right-angle tetrahedron or opal lens combination, and measured object can be fixed together with one group of birefringence beam splitter wherein, also can fix with single reflecting body.
The present invention adopts and measures traversing amount than phase method, can keep the resolution of prior art under the condition of little splitting angle.In 50 meters measurement ranges, it is straight through (hot spot 8mm-10mm for example, and two beam separations are 4mm, in fact two light beams do not separate) that the centre distances of two relevant light beams are no more than hot spot, preferably resolves the problem that air disturbs in the prior art like this.(two-beam can be thought and is in the identical atmospheric environment, air disturbs and can cancel out each other) in addition, adopt than facies principle, make the present invention can carry out continuous coverage, also can intermittently measure, solve in the engineering the coaxality measurement in many groups axle, hole and the measurement of planeness problem of noncontinuous surface.
Brief Description Of Drawings
Fig. 1, be that a kind of two-frequency laser interferometer straight line degree measurement annex of prior art is formed synoptic diagram
Fig. 2, be embodiments of the invention one structural representations.
Fig. 3, be embodiments of the invention two structural representations.
The invention provides two kinds of collimation detector embodiment that implement said method, be described in detail as follows respectively in conjunction with the accompanying drawings: embodiment one as shown in Figure 2, mainly form by following each parts, 11 is vertical double-frequency zeeman laser device, 12 is spectroscope, 12 ' is catoptron, 13 is beam expander, 14,15 are mutual two wollaston prisms to the splitting angle unanimity of putting, and 16 is right-angle prism, 17,17 ' is analyzer, and 18,18 ' is photelectric receiver, QP is a quarter-wave plate, PH is a phasometer, and its measuring principle is: zeeman laser 11 sends a branch of left and right sides rotatory polarization light that contains certain frequency difference, becomes the linearly polarized light of quadrature (if during with transverse zeeman laser or birefringence tuned laser through QP, output is that linearly polarized light then need not used QP), be divided into two parts again behind spectroscope 12, wherein a part of light beam receives conduct with reference to signal by photelectric receiver 18 behind analyzer 17.Another part is as the alignment measurement light beam, after beam expander 13 expands bundle, inject first wollaston prism 14, be divided into folder one low-angle two-beam, again through second wollaston prism 15 outgoing, become the parallel orthogonal polarized light beam that leans on very closely mutually, the two-beam fractional dose can be no more than 4mm.Two wollaston prisms are custom-designed in the present embodiment, and little beam splitting pattern and angle equate, wherein prism and measured object are fixed together.Two-beam reconsolidates and is a branch of light again after getting back to prism group 14,15 again after the right-angle prism translation reflection, is received by second photelectric receiver through analyzer 17 ' and obtains measuring-signal.Above-mentioned reference signal and measuring-signal are sent into phasometer PH than mutually, output of phasometer at this moment and prism 14 or 15 along Y to displacement proportional, through data processing, can obtain the displacement of measured object on the vertical beam of light direction.If prism is moved out of light path, reset again again, as long as prism location sets back, the output of phasometer is constant, therefore can be used for interrupted measurement.The optical path difference variation that this embodiment produces in range ability is no more than a wavelength, and promptly phase differential is no more than 360 °, so the available phases meter obtains the measurement result of monodrome.Present embodiment adopts high-precision prism to process easily than big plane mirror, has guaranteed that linear datum can reach higher precision.
Embodiments of the invention (two) as shown in Figure 3, mainly comprise vertical zeeman laser 21, spectroscope 22, catoptron 22 ', beam expander 23, separate two optically-active quartz wedge assemblies 24,25 placing, every wedge is made by the identical left-handed and right handed quartz wedge of angle, and its ordering is a right left side; About; Or about, a right left side (R represents the right side among the figure, and L represents a left side), quarter wave plate QP, right-angle prism 26, analyzer 27,27 ', photelectric receiver 28,28 ', phasometer PH.Present embodiment is with two optically-active quartz wedge assemblies 24 with the difference of implementing 1,25 replace two wollaston prisms going up in the example, like this from the left and right sides rotatory polarization light of vertical zeeman laser 21 outgoing, can not need to become line through quarter wave plate QP shakes light and directly enters optically-active quartz wedge assembly, a left side, right-handed rotation about revolve refractive index difference in the quartz wedge, thereby also be separated a very little angle, but after second wedge group, become parallel beam again, before right-angle prism 26, place a quarter wave plate QP, its effect is to guarantee that light beam former left-handed rotation when the right-angle prism backspace still is left-handed rotation, former right-handed rotation still is right-handed rotation, and present embodiment miscellaneous part and principle of work are all identical with embodiment one.
Claims (4)
1, a kind of double-frequency laser alignment measurement method comprises two-frequency laser, spectroscope, two groups of birefringence beam splitters, reflecting body, photelectric receiver, and detecting signal unit is formed, and its measuring method comprises following each step;
1) sends by said two-frequency laser and contain two kinds of frequencies, a branch of light of two kinds of polarization directions;
2) this light beam separated into two parts light behind said spectroscope, first light is received by first photelectric receiver, becomes reference signal;
3) after second portion light was injected first group of birefringence beam splitter, the light of two kinds of polarization directions of two kinds of frequencies of this Shu Hanyou was divided into and accompanies a low-angle two-beam; Again through becoming the parallel polarized light of two bundles behind second group of birefringence element;
4) directive one reflecting body simultaneously of the two-beam in the third step, and return by former road, behind said two groups of birefringence beam splitters, receive again by second photelectric receiver, become measuring-signal;
5) said detecting signal unit is made of analyzer and phasometer, and said reference signal and measuring-signal are sent into phasometer and carried out the phase bit comparison through analyzer, obtain the displacement of measured object.
2, a kind of employing double-frequency laser alignment measurement interferometer of measuring method according to claim 1, comprise the reference path and measurement light path that constitute by two-frequency laser, spectroscope, reflecting body, birefringence beam splitter, first electric receiver and detecting signal unit, it is characterized in that said birefringence beam splitter is placed on the wollaston prism that two little splitting angle types measuring in the light path and angle equate by separation and constitutes, said detecting signal unit is made of analyzer and phasometer.
3, a kind of double-frequency laser alignment measurement interferometer that adopts the described measuring method of claim 1, comprise the reference path and measurement light path that constitute by two-frequency laser, spectroscope, reflecting body, birefringence beam splitter, first electric receiver and detecting signal unit, it is characterized in that said birefringence beam splitter is placed on two group left and right sides optically-active quartz wedges of measuring in the light path by separation and constitutes, said detecting signal unit is made of analyzer and phasometer.
4,, it is characterized in that said reflecting body is a right-angle prism as claim 2 or 3 described double-frequency laser alignment measurement interferometers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN92110543A CN1036292C (en) | 1992-09-17 | 1992-09-17 | Two-frequency laser collimation measuring method and interferometer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN92110543A CN1036292C (en) | 1992-09-17 | 1992-09-17 | Two-frequency laser collimation measuring method and interferometer |
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| Publication Number | Publication Date |
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| CN1071005A CN1071005A (en) | 1993-04-14 |
| CN1036292C true CN1036292C (en) | 1997-10-29 |
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| CN92110543A Expired - Fee Related CN1036292C (en) | 1992-09-17 | 1992-09-17 | Two-frequency laser collimation measuring method and interferometer |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1095542C (en) * | 2000-02-25 | 2002-12-04 | 清华大学 | Dual-vacuum chamber and dual-frequency phase measurement air refractivity interferometer |
| CN100429475C (en) * | 2006-06-20 | 2008-10-29 | 哈尔滨工业大学 | Method and apparatus for reducing heterodyne interference nonlinear error first harmonic component |
| CN101975882A (en) * | 2010-09-16 | 2011-02-16 | 哈尔滨工业大学 | Difference-stream detecting method based on BSO (Bi12SiO20) crystal and device for realizing same |
| CN104613902B (en) * | 2011-10-14 | 2018-04-06 | 上海理工大学 | Laser interference system for displacement straight line degree measurement |
| CN104567735A (en) * | 2013-10-16 | 2015-04-29 | 北京航天计量测试技术研究所 | Dynamic small-angle resolution testing method |
| CN103900467B (en) * | 2014-03-20 | 2017-01-04 | 哈尔滨工业大学 | Single fiber coupling ball minute yardstick sensor based on polarization state detection |
| CN103983199B (en) * | 2014-05-28 | 2016-08-17 | 海宁科海光电科技有限公司 | Optical displacement sensor |
| CN104807417A (en) * | 2015-03-26 | 2015-07-29 | 北京工业大学 | Rapid measurement method for parallelism error of linear guide rails |
| CN109557547B (en) * | 2018-12-27 | 2020-10-23 | 武汉万集信息技术有限公司 | Lidar, distance measurement and/or velocity determination method and storage medium |
| CN110031851B (en) * | 2019-04-12 | 2020-10-30 | 武汉大学 | Small-angle light splitting optical-mechanical device and quick assembling and adjusting method |
| CN110514147B (en) * | 2019-08-08 | 2021-05-18 | 北京市普锐科创科技有限责任公司 | Double-frequency laser interferometer capable of simultaneously measuring roll angle and straightness |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4688941A (en) * | 1984-06-15 | 1987-08-25 | Office National D'etudes Et De Recherche Aerospatiales (Onera) | Device for analyzing and correcting wavefront surfaces in real time using a polarization interferometer |
| US4886363A (en) * | 1988-09-06 | 1989-12-12 | Eastman Kodak Company | Quadratic frequency modulated absolute distance measuring interferometry |
-
1992
- 1992-09-17 CN CN92110543A patent/CN1036292C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4688941A (en) * | 1984-06-15 | 1987-08-25 | Office National D'etudes Et De Recherche Aerospatiales (Onera) | Device for analyzing and correcting wavefront surfaces in real time using a polarization interferometer |
| US4886363A (en) * | 1988-09-06 | 1989-12-12 | Eastman Kodak Company | Quadratic frequency modulated absolute distance measuring interferometry |
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