A kind of contrast anti-interference cascade ladder corner reflector laser interferometer and scaling method and measuring method
Technical field
The present invention relates to a kind of Precision Inspection and instrument field, particularly the contrast anti-interference cascade ladder corner reflector laser interferometer of one and scaling method and measuring method.
Background technology
The appearance of laser instrument, makes ancient interference technique be developed rapidly, and laser has that brightness is high, good directionality, monochromaticity and the feature such as coherence is good, and laser interferometry techniques is comparative maturity.Laser interferometry system is applied widely: the measurement of accurate length, angle is as the detection of linear scale, grating, gauge block, precision lead screw; Position detecting system in exact instrument is as the control of precision optical machinery, correction; Position detecting system in large scale integrated circuit specialized equipment and detecting instrument; Minute sized measurement etc.At present, in most of laser interference length-measuring system, all have employed Michelson interferometer or similar light channel structure, such as, single frequency laser interferometer conventional at present.
Single frequency laser interferometer is the light beam sent from laser instrument, after beam-expanding collimation, be divided into two-way by spectroscope, and reflects can be combined in spectroscope from stationary mirror and moving reflector respectively and produce interference fringe.When moving reflector moves, the light intensity change of interference fringe is converted to electric impulse signal by the photo-electric conversion element in receiver and electronic circuit etc., after shaping, amplification, input up-down counter calculate overall pulse number N, calculating formula L=N × λ/2 are pressed again by robot calculator, in formula, λ is optical maser wavelength, calculates the displacement L of moving reflector.
In actual use, present inventor finds, above-mentioned measurement structure and measuring method still also exist deficiency:
Also there is serious problem affected by environment in current single frequency laser interferometer, when laser interferometer moveable mirror moves, the light intensity change of interference fringe is converted to electric impulse signal by the photo-electric conversion element in receiver and electronic circuit etc., when for the strongest constructive interference, the triggering level that signal exceedes counter goes on record, if environment changes, such as air turbulence, in air, impurity increases, lathe mist of oil, add the impact of cutting swarf on laser beam in man-hour, the intensity of laser beam is reduced, now, even there is the strongest constructive interference, also likely intensity is not counted lower than the triggering level of counter.
So, based on above-mentioned deficiency, need one at present badly and namely can environment resistant disturb, the laser interferometer of measuring accuracy can be improved again.
Summary of the invention
The object of the invention is to the deficiency for current laser interferometer environment resistant interference performance difference, provide a kind of can environment resistant interference laser interferometer.
In order to realize foregoing invention object, the invention provides following technical scheme:
A kind of contrast anti-interference cascade ladder corner reflector laser interferometer, includes lasing light emitter, ladder corner reflector group, interferometry photodetector group, angle of critical deformation catoptron and spectroscope group;
Described lasing light emitter restraints laser beam to described spectroscope group injection z, wherein z be greater than or equal to 2 positive integer, described interferometry photodetector group includes z interferometry photodetector, and each interferometry photodetector is corresponding with beam of laser bundle;
Each laser beam is divided into the first laser beam group and the second laser beam group after described spectroscope group, ladder corner reflector group described in described first laser beam group directive, spectroscope group described in directive again after the reflection of described ladder corner reflector group, interferometry photodetector group described in directive after described spectroscope group again, angle of critical deformation catoptron described in described second laser beam group directive, spectroscope group described in directive again after the reflection of described angle of critical deformation catoptron, corresponding interfering with the first laser beam group of interferometry photodetector group described in directive after described spectroscope group, form coherence laser beam group, each interfering beam each self-corresponding described interferometry photodetector of directive respectively of coherence laser beam group,
Described ladder corner reflector group includes two ladder corner reflectors and a fixed angles catoptron, each ladder corner reflector has two reflective steps faces at a right angle, each described reflective steps face comprises the plane of reflection that z becomes notch cuttype, when first laser beam group injects described ladder corner reflector group, first be mapped on a reflective steps face of one of them ladder corner reflector, the z of the first laser beam group restraints z the plane of reflection one_to_one corresponding in laser and this reflective steps face, be mapped on another reflective steps face of this ladder corner reflector after the reflection of this reflective steps face, fixed angles catoptron described in directive more after reflection, another ladder corner reflector of directive again after the reflection of fixed angles catoptron, after the reflection of this ladder corner reflector, spectroscope group described in directive again,
Described contrast anti-interference cascade ladder corner reflector laser interferometer also includes reflection measurement photodetector group, described reflection measurement photodetector group includes z reflection measurement photodetector, described second laser beam group is also formed with reflection lasering beam group after by spectroscope group described in described angle of critical deformation catoptron directive, each laser beam described reflection measurement photodetector of directive one respectively of described reflection lasering beam group.
As further preferred version, described spectroscope group includes the first spectroscope and the second spectroscope, the z of described lasing light emitter injection restraints laser beam and is first mapped to the first spectroscope, the first laser beam group is formed through the first dichroic mirror, the second laser beam group is formed through the first spectroscope transmission, ladder corner reflector group described in first laser beam group directive, first spectroscope described in directive again after reflection, and then transmitted through described first spectroscope, angle of critical deformation catoptron described in described second laser beam group directive, the second spectroscope described in directive after described angle of critical deformation catoptron reflection, the first spectroscope described in directive after described second spectroscope transmission, and interfere with the first laser beam group transmitted from described first spectroscope, interferometry photodetector group described in directive after formation coherence laser beam group, also described reflection lasering beam group is formed by described second dichroic mirror by second spectroscopical described second laser beam group described in described angle of critical deformation catoptron directive.
The laser interferometer of the application, because reflection measurement photodetector group can measure the intensity of angle of critical deformation catoptron reflection lasering beam group, according to the interference state of the intensity determination laser interference light beam of reflection lasering beam group, so realizes the object of environment resistant interference.
Disclosed herein as well is a kind of scaling method adopting above-mentioned laser interferometer structure,
For a scaling method for contrast anti-interference cascade ladder corner reflector laser interferometer, comprise the steps:
Step one, position adjustment: the position of adjusting lasing light emitter, ladder corner reflector group, spectroscope group, interferometry photodetector group, reflection measurement photodetector group and angle of critical deformation catoptron;
Step 2, adjustment light path: start described lasing light emitter, the position of further accurate adjustment ladder corner reflector group, spectroscope group, interferometry photodetector group, reflection measurement photodetector group and angle of critical deformation catoptron, makes the light path of laser interferometer reach designing requirement;
Step 3, generate and the most capable and experiencedly relate to database: choose an interferometry photodetector in interferometry photodetector group as demarcation interferometry photodetector, choose a reflection measurement photodetector in reflection measurement photodetector group as demarcation reflection measurement photodetector, described demarcation interferometry photodetector is corresponding with same a branch of laser beam that described demarcation reflection measurement photodetector and described lasing light emitter penetrate, mobile described angle of critical deformation catoptron under the environment of air cleaning, when the interfering beam demarcating interferometry photodetector described in directive fixes described angle of critical deformation catoptron for during the strongest constructive interference, record is now demarcated reflection measurement photodetector reading and is demarcated interferometry photodetector reading, changing air ambient makes described demarcation reflection measurement photodetector reading change, record the demarcation interferometry photodetector reading that several demarcate reflection measurement photodetector reading and correspondence simultaneously, obtain the most capable and experiencedly relating to database.
As further preferred version, repeating said steps three, chooses different demarcation reflection measurement photodetectors at every turn and demarcates interferometry photodetector, obtains z and the most capable and experiencedly relates to database.Owing to being repeated step 3, obtain z the database that relates to the most capable and experienced, the quantity of the database of direct increase, more be beneficial to the matching inquiry of data in testing process, and, realizing multiwavelength laser source, ladder corner reflector group and z, the most capable and experienced to relate between database mutually collaborative, improves the measuring accuracy of laser interferometer.
The laser interferometer structure of the application and scaling method, when the strongest constructive interference, change measurement environment, record is demarcated reflection measurement photodetector reading and is demarcated interferometry photodetector reading and forms the most capable and experienced database that relates to, in actual measurement process, if exist when to cause interferometry photodetector group the strongest constructive interference normally can not be detected due to environmental factor, can compare with the most capable and experienced data related in database according to demarcation reflection measurement photodetector reading and demarcation interferometry photodetector reading, if have matched data, then this position is the strongest constructive interference, the laser interferometer of the application is so made to realize the ability of environment resistant interference.
As further preferred version, also include step 4, generate the most weak interference data storehouse: mobile described angle of critical deformation catoptron under the environment of air cleaning, when the interfering beam demarcating interferometry photodetector described in directive fixes described angle of critical deformation catoptron for during the most weak destructive interference, record is now demarcated reflection measurement photodetector reading and is demarcated interferometry photodetector reading, changing air ambient makes described demarcation reflection measurement photodetector reading change, record the demarcation interferometry photodetector reading that several demarcate reflection measurement photodetector reading and correspondence simultaneously, obtain the most weak interference data storehouse.
As further preferred version, repeating said steps four, chooses different demarcation reflection measurement photodetectors at every turn and demarcates interferometry photodetector, obtains z interference data storehouse the most weak.
As further preferred version, also include step 5, generate 1/n wavelength-interferometric database, n be greater than or etc. 2 positive integer, mobile described angle of critical deformation catoptron under the environment of air cleaning, when the interfering beam demarcating interferometry photodetector described in directive is for the strongest constructive interference, continue the distance of mobile 1/2n wavelength again, record is now demarcated reflection measurement photodetector reading and is demarcated interferometry photodetector reading, then changing air ambient makes described demarcation reflection measurement photodetector reading change, record the demarcation interferometry photodetector reading demarcating reflection measurement photodetector reading and correspondence described in several simultaneously, obtain 1/n wavelength-interferometric database.
When two bundle laser interfere, optical path difference between the strongest adjacent constructive interference and the most weak destructive interference is half wavelength, in the scaling method of the application, to the strongest constructive interference, the most weak destructive interference, 1/n wavelength-interferometric is all demarcated, that is, when adopting the laser interferometer of the application to carry out actual measurement, according to demarcation reflection measurement photodetector reading and interferometry photodetector reading and the most capable and experienced database that relates to can be demarcated, the most weak interference data storehouse, data in 1/n wavelength-interferometric database are compared, determine that this position is the strongest constructive interference according to the match condition of data, the most weak destructive interference or 1/n wavelength-interferometric.The laser interferometer of the application environment resistant can not only be disturbed, but also improve measuring accuracy.
As further preferred version, repeating said steps five, chooses different demarcation reflection measurement photodetectors at every turn and demarcates interferometry photodetector, obtaining z 1/n wavelength-interferometric database.
The invention also discloses a kind of measuring method adopting above-mentioned laser interferometer and scaling method,
A kind of measuring method adopting contrast anti-interference cascade ladder corner reflector laser interferometer and scaling method:
In actual measurement environment, if the signal reading that described demarcation reflection measurement photodetector measures is x, the signal reading that the measurement of described demarcation interferometry photodetector obtains is y, by x value and y value at the most capable and experienced database that relates to, the most weak interference data storehouse, compare in 1/n wavelength-interferometric database, when x value and y value match with the most capable and experienced a certain class value related in database, then think that this position is the strongest constructive interference position, when x value and y value match with a certain class value in the most weak interference data storehouse, then think that this position is the most weak destructive interference position, when a certain class value in x value and y value and 1/n wavelength-interferometric database matches, then think that this position is 1/n wavelength-interferometric position.
The measuring method of the application, determines the interference situation of current interfering beam by x value and y value, realize the ability of environment resistant interference, also improve measuring accuracy simultaneously with this.
As further preferred version, the matching threshold △ of setting y value, database is related to if the most capable and experienced, the most weak interference data storehouse, demarcating numerical value corresponding to measured interference light electric explorer in 1/n wavelength-interferometric database is y ', according to x value to the most capable and experienced database that relates to, the most weak interference data storehouse, 1/n wavelength-interferometric database carries out the inquiry of y ', if there is y ' to make | y-y'|< △, distinguish the database at y ' place again, if y ' relates in database the most capable and experienced, then think that this position is the strongest constructive interference position, if y ' is in the most weak interference data storehouse, then think that this position is the most weak destructive interference position, if y ' is in 1/n wavelength-interferometric database, then think that this position is 1/n wavelength-interferometric position.
As further preferred version, database is related to if the most capable and experienced, the most weak interference data storehouse, demarcating numerical value corresponding to reflection measurement photodetector in 1/n wavelength-interferometric database is x ', in actual measurement, select closest to the x ' of actual measured value x as matching value, according to x ' value to the most capable and experienced database that relates to, the most weak interference data storehouse, 1/n wavelength-interferometric database carries out y ' to be inquired about, if there is y ' to make | y-y'|< △, distinguish the database at y ' place again, if y ' relates in database the most capable and experienced, then think that this position is the strongest constructive interference position, if y ' is in the most weak interference data storehouse, then think that this position is the most weak destructive interference position, if y ' is in 1/n wavelength-interferometric database, then think that this position is 1/n wavelength-interferometric position.
As further preferred version, the size of described matching threshold △ ensures when carrying out data query, when meeting | during y-y'|< △, y ' is unique value.When matching threshold △ is larger, may occur that one group of x value and y value match two groups or organize x ' value and y ' value more, make troubles to measurement, so first matching threshold △, make one group of x value and y value coupling one group of x ' value and y ' value at most in measuring process, be convenient for measuring.
As further preferred version, the size of described matching threshold △ sets according to the accuracy requirement of actual measurement, when the high-precision measured value of needs, adopts less matching threshold, when not needing high-acruracy survey value, adopts larger matching threshold.
As further preferred version, if △=5%.
In the measuring method of the application, by arranging matching threshold △, needing according to Surveying Actual Precision the size that matching threshold △ is set, being convenient for measuring in process with this, the match selection of data, reduce and measure difficulty.
Compared with prior art, beneficial effect of the present invention:
The contrast anti-interference cascade ladder corner reflector laser interferometer of the application, first by arranging multiple beam, ladder corner reflector group and corner reflector improve the measuring accuracy of laser interferometer, simultaneously by arranging reflection measurement photodetector, after laser interferometry environment changes, can by measuring angle of critical deformation catoptron reflects laser intensity, the no longer direct signal magnitude by interferometry photodetector group of laser interference state is determined, but jointly determined by reflection measurement photodetector and interferometry photodetector group, so realize the antijamming capability of laser interferometer.
The beneficial effect of other embodiments of the application:
The laser interferometer of the application, the position of the strongest constructive interference can not only be determined, but also position and the 1/n wavelength-interferometric position of the most weak destructive interference can be determined, the laser interferometer of the application environment resistant can not only be disturbed, but also improve measuring accuracy; Further, cooperatively interact between the measuring method of the application, scaling method, multi-beam laser source, ladder corner reflector group, further improve the measuring accuracy of the application's laser interferometer.
Accompanying drawing illustrates:
Fig. 1 is the light path schematic diagram of laser interferometer structure of the present invention;
Fig. 2 is the structural representation of angle of critical deformation catoptron when moving,
Mark in figure:
1-lasing light emitter, 2-ladder corner reflector group, 3-angle of critical deformation catoptron, 4-interferometry photodetector group, 5-spectroscope group, 6-reflection measurement photodetector group, 7-first laser beam group, 8-second laser beam group, 9-reflection lasering beam group, 21-ladder corner reflector, 22-fixed angles catoptron, 41-interferometry photodetector, 41a-demarcates interferometry photodetector, 51-first spectroscope, 52-second spectroscope, 61-reflection measurement photodetector, 61a-demarcates reflection measurement photodetector.
Embodiment
Below in conjunction with test example and embodiment, the present invention is described in further detail.But this should be interpreted as that the scope of the above-mentioned theme of the present invention is only limitted to following embodiment, all technology realized based on content of the present invention all belong to scope of the present invention.
Embodiment 1, as shown in the figure, a kind of contrast anti-interference cascade ladder corner reflector laser interferometer, includes lasing light emitter 1, ladder corner reflector group 2, interferometry photodetector group 4, angle of critical deformation catoptron 3 and spectroscope group 5;
Described lasing light emitter 1 penetrates z to described spectroscope group 5 and restraints laser beam, wherein z be greater than or equal to 2 positive integer, described interferometry photodetector group 4 includes z interferometry photodetector, and each interferometry photodetector 41 is corresponding with beam of laser bundle;
Each laser beam is divided into the first laser beam group 7 and the second laser beam group 8 after described spectroscope group 5, ladder corner reflector group 2 described in described first laser beam group 7 directive, spectroscope group 5 described in directive again after the reflection of described ladder corner reflector group 2, interferometry photodetector group 4 described in directive after described spectroscope group 5 again, angle of critical deformation catoptron 3 described in described second laser beam group 8 directive, spectroscope group 5 described in directive again after described angle of critical deformation catoptron 3 reflects, corresponding interfering with the first laser beam group 7 of interferometry photodetector group 4 described in directive after described spectroscope group 5, form coherence laser beam group, each interfering beam each self-corresponding described interferometry photodetector 41 of directive respectively of coherence laser beam group,
Described ladder corner reflector group 2 includes two ladder corner reflectors 21 and a fixed angles catoptron 22, each ladder corner reflector 21 has two reflective steps faces at a right angle, each described reflective steps face comprises the plane of reflection that z becomes notch cuttype, when first laser beam group 7 injects described ladder corner reflector group 2, first be mapped on a reflective steps face of one of them ladder corner reflector 21, the z of the first laser beam group restraints z the plane of reflection one_to_one corresponding in laser and this reflective steps face, be mapped on another reflective steps face of this ladder corner reflector after the reflection of this reflective steps face, fixed angles catoptron 22 described in directive more after reflection, another ladder corner reflector 21 of directive again after fixed angles catoptron 22 reflects, after the reflection of this ladder corner reflector 21, spectroscope group 5 described in directive again,
Described contrast anti-interference cascade ladder corner reflector laser interferometer also includes reflection measurement photodetector group 6, described reflection measurement photodetector group 6 includes z reflection measurement photodetector 61, described second laser beam group 8 is also formed with reflection lasering beam group 9 after by spectroscope group 5 described in described angle of critical deformation catoptron 3 directive, each laser beam described reflection measurement photodetector 61 of directive one respectively of described reflection lasering beam group 9.
As further preferred version, described spectroscope group 5 includes the first spectroscope 51 and the second spectroscope 52, the z that described lasing light emitter 1 penetrates restraints laser beam and is first mapped to the first spectroscope 51, the first laser beam group 7 is reflected to form through the first spectroscope 51, the second laser beam group 8 is formed through the first spectroscope 51 transmission, ladder corner reflector group 2 described in first laser beam group 7 directive, first spectroscope 51 described in directive again after reflection, and then transmitted through described first spectroscope 51, angle of critical deformation catoptron 3 described in described second laser beam group 8 directive, the second spectroscope 52 described in directive after described angle of critical deformation catoptron 3 reflects, the first spectroscope 51 described in directive after described second spectroscope 52 transmission, and interfere with the first laser beam group 7 transmitted from described first spectroscope 51, interferometry photodetector group 4 described in directive after formation coherence laser beam group, also described reflection lasering beam group 9 is reflected to form by described second spectroscope 52 by the described second laser beam group 8 of the second spectroscope 52 described in described angle of critical deformation catoptron 3 directive.
The laser interferometer of the application, because reflection measurement photodetector group 6 can measure the intensity of angle of critical deformation catoptron 3 reflection lasering beam group 9, according to the interference state of the intensity determination laser interference light beam of reflection lasering beam group 9, so realize the object of environment resistant interference.
As further preferred version, the laser beam in described lasing light emitter 1, ladder corner reflector group 2, interferometry photodetector group 4, spectroscope group 5, reflection measurement photodetector group 6 between any two is arranged in enclosure space and does not contact with Outdoor Space.In this application, laser beam between any two of lasing light emitter 1, ladder corner reflector group 2, interferometry photodetector group 4, spectroscope group 5 and these parts of reflection measurement photodetector group 6 is arranged in enclosure space, make carrying out in the process measured, laser beam between these parts above-mentioned can't be subject to the impact of environmental factor, and then ensure that the measuring accuracy of the application's laser interferometer.
As further preferred version, the laser beam between described spectroscope group 5 and described angle of critical deformation catoptron 3 is exposed among surrounding air.When reality uses, angle of critical deformation catoptron 3 is arranged on testee, move with testee, so in this application, laser beam between spectroscope group 5 and angle of critical deformation catoptron 3 is exposed among surrounding air, first be make the application's laser interferometer structure simple, also facilitate the layout of the application's laser interferometer simultaneously.
Embodiment 2, as shown in the figure, a kind of scaling method for contrast anti-interference cascade ladder corner reflector laser interferometer, comprises the steps:
Step one, position adjustment: the position of adjusting lasing light emitter 1, ladder corner reflector group 2, spectroscope group 5, interferometry photodetector group 4, reflection measurement photodetector group 6 and angle of critical deformation catoptron 3;
Step 2, adjustment light path: start described lasing light emitter 1, the position of further accurate adjustment ladder corner reflector group 2, spectroscope group 5, interferometry photodetector group 4, reflection measurement photodetector group 6 and angle of critical deformation catoptron 3, makes the light path of laser interferometer reach designing requirement;
Step 3, generate and the most capable and experiencedly relate to database: choose an interferometry photodetector 41 in interferometry photodetector group 4 as demarcation interferometry photodetector 41a, choose a reflection measurement photodetector 61 in reflection measurement photodetector group 6 as demarcation reflection measurement photodetector 61a, described demarcation interferometry photodetector 41a is corresponding with same a branch of laser beam that described demarcation reflection measurement photodetector 61a and described lasing light emitter 1 penetrate, mobile described angle of critical deformation catoptron 3 under the environment of air cleaning, when the interfering beam demarcating interferometry photodetector 41a described in directive fixes described angle of critical deformation catoptron 3 for during the strongest constructive interference, record is now demarcated reflection measurement photodetector 61a reading and is demarcated interferometry photodetector 41a reading, changing air ambient makes described demarcation reflection measurement photodetector 61a reading change, record the demarcation interferometry photodetector 41a reading that several demarcate reflection measurement photodetector 61a reading and correspondence simultaneously, obtain the most capable and experiencedly relating to database.
As further preferred version, repeating said steps three, chooses different demarcation reflection measurement photodetector 61a at every turn and demarcates interferometry photodetector 41a, obtains z and the most capable and experiencedly relates to database.
The laser interferometer structure of the application and scaling method, when the strongest constructive interference, change measurement environment, record is demarcated reflection measurement photodetector reading 61a and is demarcated interferometry photodetector 41a reading and forms the most capable and experienced database that relates to, in actual measurement process, if exist when to cause interferometry photodetector group 4 the strongest constructive interference normally can not be detected due to environmental factor, can compare with the most capable and experienced data related in database according to demarcation reflection measurement photodetector 61a reading and demarcation interferometry photodetector 41a reading, if have matched data, then this position is the strongest constructive interference, the laser interferometer of the application is so made to realize the ability of environment resistant interference.
As further preferred version, also include step 4, generate the most weak interference data storehouse: mobile described angle of critical deformation catoptron 3 under the environment of air cleaning, when the interfering beam demarcating interferometry photodetector 41a described in directive fixes described angle of critical deformation catoptron 3 for during the most weak destructive interference, record is now demarcated reflection measurement photodetector 61a reading and is demarcated interferometry photodetector 41a reading, changing air ambient makes described demarcation reflection measurement photodetector 61a reading change, record the demarcation interferometry photodetector 41a reading that several demarcate reflection measurement photodetector 61a reading and correspondence simultaneously, obtain the most weak interference data storehouse.
As further preferred version, repeating said steps four, chooses different demarcation reflection measurement photodetector 61a at every turn and demarcates interferometry photodetector 41a, obtain z interference data storehouse the most weak.
As further preferred version, also include step 5, generate 1/n wavelength-interferometric database, n be greater than or etc. 2 positive integer, mobile described angle of critical deformation catoptron 3 under the environment of air cleaning, when the interfering beam demarcating interferometry photodetector 41a described in directive is for the strongest constructive interference, continue the distance of mobile 1/2n wavelength again, record is now demarcated reflection measurement photodetector reading 61a and is demarcated interferometry photodetector 41a reading, then changing air ambient makes described demarcation reflection measurement photodetector 61a reading change, record the demarcation interferometry photodetector 41a reading demarcating reflection measurement photodetector 61a reading and correspondence described in several simultaneously, obtain 1/n wavelength-interferometric database.
When two bundle laser interfere, optical path difference between the strongest adjacent constructive interference and the most weak destructive interference is half wavelength, in the scaling method of the application, to the strongest constructive interference, the most weak destructive interference, 1/n wavelength-interferometric is all demarcated, that is, when adopting the laser interferometer of the application to carry out actual measurement, according to demarcation reflection measurement photodetector 61a reading and interferometry photodetector 41a reading and the most capable and experienced database that relates to can be demarcated, the most weak interference data storehouse, data in 1/n wavelength-interferometric database are compared, determine that this position is the strongest constructive interference according to the match condition of data, the most weak destructive interference or 1/n wavelength-interferometric.The laser interferometer of the application environment resistant can not only be disturbed, but also improve measuring accuracy.
As further preferred version, repeating said steps five, chooses different demarcation reflection measurement photodetector 61a at every turn and demarcates interferometry photodetector 41a, obtain z 1/n wavelength-interferometric database.
Embodiment 3, as shown in the figure, a kind of measuring method adopting contrast anti-interference cascade ladder corner reflector laser interferometer and scaling method:
In actual measurement environment, if the signal reading that described demarcation reflection measurement photodetector 61a measures is x, the signal reading that described demarcation interferometry photodetector 41a measurement obtains is y, by x value and y value at the most capable and experienced database that relates to, the most weak interference data storehouse, compare in 1/n wavelength-interferometric database, when x value and y value match with the most capable and experienced a certain class value related in database, then think that this position is the strongest constructive interference position, when x value and y value match with a certain class value in the most weak interference data storehouse, then think that this position is the most weak destructive interference position, when a certain class value in x value and y value and 1/n wavelength-interferometric database matches, then think that this position is 1/n wavelength-interferometric position.
The measuring method of the application, determines the interference situation of current interfering beam by x value and y value, realize the ability of environment resistant interference, also improve measuring accuracy simultaneously with this.
As further preferred version, the matching threshold △ of setting y value, database is related to if the most capable and experienced, the most weak interference data storehouse, demarcating numerical value corresponding to measured interference light electric explorer in 1/n wavelength-interferometric database is y ', according to x value to the most capable and experienced database that relates to, the most weak interference data storehouse, 1/n wavelength-interferometric database carries out the inquiry of y ', if there is y ' to make | y-y'|< △, distinguish the database at y ' place again, if y ' relates in database the most capable and experienced, then think that this position is the strongest constructive interference position, if y ' is in the most weak interference data storehouse, then think that this position is the most weak destructive interference position, if y ' is in 1/n wavelength-interferometric database, then think that this position is 1/n wavelength-interferometric position.
As further preferred version, database is related to if the most capable and experienced, the most weak interference data storehouse, demarcating numerical value corresponding to reflection measurement photodetector 61a in 1/n wavelength-interferometric database is x ', in actual measurement, select closest to the x ' of actual measured value x as matching value, according to x ' value to the most capable and experienced database that relates to, the most weak interference data storehouse, 1/n wavelength-interferometric database carries out y ' to be inquired about, if there is y ' to make | y-y'|< △, distinguish the database at y ' place again, if y ' relates in database the most capable and experienced, then think that this position is the strongest constructive interference position, if y ' is in the most weak interference data storehouse, then think that this position is the most weak destructive interference position, if y ' is in 1/n wavelength-interferometric database, then think that this position is 1/n wavelength-interferometric position.
As further preferred version, the size of described matching threshold △ ensures when carrying out data query, when meeting | during y-y'|< △, y ' is unique value.When matching threshold △ is larger, may occur that one group of x value and y value match two groups or organize x ' value and y ' value more, make troubles to measurement, so first matching threshold △, make one group of x value and y value coupling one group of x ' value and y ' value at most in measuring process, be convenient for measuring.
As further preferred version, the size of described matching threshold △ sets according to the accuracy requirement of actual measurement, when the high-precision measured value of needs, adopts less matching threshold, when not needing high-acruracy survey value, adopts larger matching threshold.
As further preferred version, if △=5%.
In the measuring method of the application, by arranging matching threshold △, needing according to Surveying Actual Precision the size that matching threshold △ is set, being convenient for measuring in process with this, the match selection of data, reduce and measure difficulty.
Above embodiment only in order to the present invention is described and and unrestricted technical scheme described in the invention, although this instructions with reference to each above-mentioned embodiment to present invention has been detailed description, but the present invention is not limited to above-mentioned embodiment, therefore anyly the present invention is modified or equivalent to replace; And all do not depart from technical scheme and the improvement thereof of the spirit and scope of invention, it all should be encompassed in the middle of right of the present invention.