Background technology
Along with the updating and improve of measuring technique, the development of modernized high-acruracy survey technology and azimuth aiming tracker has proposed more and more higher requirement to low-angle measuring accuracy.Photoelectric auto-collimator is in the low-angle precision measurement, the high precision aiming has irreplaceable effect with the aspect, location, can be used as the ingredient of optical metrological instruments such as angular instrument, optical comparator, can be used for separately also that surveying instrument is used for optical measurement, aero-space instrument is debug and aspects such as military spacecraft attitude measurement.
In the high precision small angle measurement, be better than 0.5 for uncertainty of measurement " photoelectric auto-collimator, the angle drift value of the Lights section light beam is the main source of photoelectric auto-collimator measuring error.When there is beam drift in the light beam that sends when light source, cause that as helium-neon laser resonator cavity internal reflector modification the angle drift value of light beam is: 10
-6~10
-7Rad, that is: 0.02 "~0.2 " (1. ten thousand Deans. laser datum high-acruracy survey technology. the .1999 of National Defense Industry Press June; 2. square Zhong Yan, Yin Chunyong, Liang Jinwen. the research of high-precision laser collimation technique (one). aviation instrumentation technology .1997,17 (1): 3-6), if adopt the Facula Center Location method then spot center that receiver receives is drifted about with beam drift; If adopt profile centralized positioning method, then owing to beam drift, the center of energy of the hot spot that receiver receives and the geometric center of profile do not overlap the skew that causes the profile center, directly produce the deviations at profile center.If this angle drift value is not revised or is compensated, with directly feeding back to the measurement of angle deviation that low-angle measurement result causes, cause the instrument data poor repeatability, stability is bad.If will further improve uncertainty of measurement, only rely on the collimation precision that improves light beam self, all be to be difficult to realize on still being technological and manufacturing level from prior art.Adopt error separating and compensation technique, particularly dynamic compensation technology, be the measurement of angle deviation of eliminating or this angle drift value of compensation correction causes, realize that high-precision small angle measurement provides a kind of otherwise effective technique approach.
At present, widely used photoelectric auto-collimator in the engineering, the 702 type photoelectric auto-collimators of producing as Beijing gauging instrument factory of State Metrological Bureau, adopt the optical autocollimating principle, utilize the ammeter nulling to determine the aiming state, from microdrum or direct reading from the ammeter, measurement resolution 0.1 "; uncertainty of measurement is: be 2 in 10 ' scope " is 0.5 in any 4 '~6 ' scope in center, visual field " (Wu Jinxie. the geometric sense Technology of Precision Measurement. the .1989 of publishing house of Harbin Institute of Technology September).What this measurement scheme was measured is the one dimension angular metric, if measure another dimension angular metric, must readjust instrument on this direction, causes the loaded down with trivial details and data poor repeatability of measuring process, can introduce the hysterisis error of artificial measuring error and machinery simultaneously; The angle drift value of light beam still exists simultaneously, and uncertainty of measurement is difficult to improve.
In order to overcome autocollimator when measuring the angular metric of both direction, secondary is adjusted the shortcoming of the poor repeatability that instrument brought, improve the measurement resolution of photoelectric auto-collimator, can satisfy simultaneously the needs that data in real time shows and stores, many producers and scientific research institutions all produce the photoelectric auto-collimator that adopts the high precision photoelectric sensitive detection parts to measure two dimension angular, for example:
1. the photoelectric auto-collimator of the ELCOMAT vario model that German ELCOMAT company produces.Adopt high-precision ccd image sensor, accurately measure the small angle variation amount of measuring catoptron by the displacement that the spot center that receives on the measurement ccd image sensor moves, the technical indicator of the twin shaft autocollimator of product E LCOMAT vario 500T/D65 is: be 24 in X-axis ', Y-axis is 18 ' measurement range in uncertainty of measurement be ± 0.4 " (the German M6LLER-WEDEL ELCOMAT vario of company twin shaft autocollimator Chinese operation manual .2004);
2. the two-dimentional angular displacement of the tested catoptron of patent 98229708.4 " dynamic photoelectric self-collimater " causes rectangular opening to resemble the two-dimensional linear displacement of spot, can obtain the two-dimentional angular displacement of tested catoptron by the output of calculating four quadrants on the four-quadrant photo detector;
3. patent 99242552.2 " the explicit autocollimator of two-dimentional dynamic number " changes the cross graticule in the existing one dimension autocollimator into the triangular form graticule.A spectroscope is installed between semi-permeable diaphragm block prism and two groove graticule, and spectroscope reflection image place has-the CCD receiver, and electronic measuring device is controlled and data processing the information of CCD receiver;
4. the graticule of patent 99254139.5 " photoelectric auto-collimator " is provided with the index line pattern of band N font, ∧ type, ∨ type etc., the conjugate focal planes place of Amici prism is provided with one dimension image detector spare, calculates the drift angle by the mutual alignment relation of index line pattern and one dimension image detection device;
5. patent 200410032713.2 " autocollimator " provides a kind of coarse adjustment of the normal slope that can carry out the measuring object thing simultaneously and the autocollimator of fine setting, by laser to measuring object thing radiation source, make from the next return light of measuring object thing reflection and assemble by convex lens, further become directional light by concavees lens, be mapped to first screen then, detect the normal slope of measuring object thing thus;
Owing to adopted high-precision photoelectric detector, especially ccd image sensor, realized the automatic measurement of two dimension angular when improving measurement resolution, data in real time shows and storage, and has well eliminated because the artificial measuring error that secondary adjustment instrument is introduced and the shortcoming of mechanical hysterisis error.
But in actual applications, especially all there is following weak point in above-mentioned as can be known measurement scheme on light path and physical construction and the measuring process: owing to do not adopt the means of any error compensation or correction, the angle drift value of light beam is not eliminated in measuring process, is blended in the measurement of angle deviation that causes in the measurement result at last.The measurement stability and the poor repeatability that directly cause photoelectric auto-collimator, uncertainty of measurement is difficult to further raising, limited the range of application of photoelectric auto-collimator greatly, this is the weak point of this measurement scheme itself, also is unsolved major issue in the practical application of current photoelectric auto-collimator.
Summary of the invention
The objective of the invention is to overcome the deficiency that exists in the above-mentioned existing photoelectric auto-collimator measurement scheme, a kind of 2 D photoelectric autocollimation and measuring method based on the dynamic differential compensation method is provided, adopt novel common light path optics difference structure, change the angle drift value of light beam into common-mode error, the measurement of angle deviation that the angle drift value of real-time separation and dynamic compensation light beam causes, measurement stability, repeatability and the uncertainty of measurement of raising 2 D photoelectric autocollimator.
The technical solution that the present invention adopts is: a kind of 2 D photoelectric autocollimation based on the dynamic differential compensation method, comprise light source, graticule, ccd image sensor, Amici prism, collimator objective and the measurement catoptron placed successively, between collimator objective and measurement catoptron, place a beam split eyeglass.
Amici prism can adopt polarization splitting prism, places a λ/4 wave plates between polarization splitting prism and collimator objective.
Light source is laser instrument or light emitting diode (LED).
Graticule is the lighttight graticule of graticule or etching position of etching position printing opacity.
The beam split eyeglass is that the two sides of optical base-substrate is coated with spectro-film and anti-reflection film respectively, the surfaceness of optical base-substrate is better than 0.08um, the depth of parallelism on eyeglass two sides is less than 10 ", the splitting ratio of the spectro-film that plates is: 52/48≤T/R≤72/28, anti-reflection film requires transmitance factor alpha 〉=99%.
The present invention also provides the measuring method based on the 2 D photoelectric autocollimation of dynamic differential compensation method, and this method may further comprise the steps:
1. adjust the beam split eyeglass, make the reference hot spot and the measurement hot spot that receive on the ccd image sensor separate fully; The adjustment fixing beam split eyeglass in back that finishes is calibrated this device then, after the calibration this device in use the beam split eyeglass no longer adjust;
2. the light beam that light source is sent illuminates the graticule on the focus that is positioned at collimator objective;
3. this light beam is through behind the Amici prism, and transmitted light beam becomes parallel collimated light beam through collimator objective and incides the beam split eyeglass, and light beam is divided into folded light beam and transmitted light beam;
4. folded light beam is directly returned by former road, assembles through collimator objective, and Amici prism reflection back is received by ccd image sensor, becomes reference signal;
5. after the transmission of transmitted light beam process beam split eyeglass, become measuring beam and incide the measurement catoptron that is placed on the measured object, after the light beam process beam split eyeglass transmission that the measurement mirror reflects is returned, assemble by collimator objective, through imaging on the ccd image sensor after the Amici prism reflection, become measuring-signal;
6. monitor and isolate the angle drift value of light beam by reference signal, carry out real-time differential processing and get final product the measurement of angle deviation that this angle drift value of dynamic compensation causes, accurately measure the variable quantity of Bidimensional small angle:
θ=(d
1-d
0)/2f
Here: θ is the variable quantity of the Bidimensional small angle of measurement catoptron, d
1And d
0Be respectively measuring-signal and reference signal.The variable quantity of the spot center position that forms on ccd image sensor, f are the equivalent focal length of collimator objective.
The present invention has following characteristics and good result:
1. made full use of common path difference dynamic characteristic and improved optical system, changed the angle drift value of light beam into common-mode error by adopting common light path optics difference structure that the beam split eyeglass constitutes, this is one of innovative point that is different from existing photoelectric auto-collimation measuring technique;
2. in design, the angle drift value of light beam causes that reference signal and measuring-signal change simultaneously, ccd image sensor obtains the two dimension angular information of reference signal and measuring-signal simultaneously, can separate the measurement of angle deviation that the angle drift value with the dynamic compensation light beam causes in real time, this be different from existing photoelectric auto-collimation measuring technique innovative point two;
3. present design has adopted foolproof structure, only in light path, add a slice beam split eyeglass, the measurement of angle deviation that angle drift value that can the dynamic compensation light beam causes, the measurement stability and the repeatability of 2 D photoelectric autocollimator have been improved, the needs that high precision two-dimensional narrow angle is measured have been satisfied, and measuring process and all obviously simplification of data processing, practical.
Embodiment
Below in conjunction with figure and embodiment 2 D photoelectric autocollimation and the measuring method based on the dynamic differential compensation method of the present invention is described in detail:
As shown in Figure 1, device of the present invention is made of light source 1, graticule 2, ccd image sensor 3, Amici prism 4, collimator objective 5, beam split eyeglass 6, measurement catoptron 7 etc.The path of its light is as follows:
The light beam that light source 1 sends illuminates the graticule 2 on the focus that is positioned at collimator objective 5, through behind the Amici prism 4, transmitted light beam becomes parallel collimated light beam through collimator objective 5 and incides beam split eyeglass 6, light beam is divided into folded light beam and transmitted light beam: folded light beam is directly returned through former road, assemble through collimator objective 5, received by ccd image sensor 3 by Amici prism 4 reflection backs, the spot center position of formation becomes reference signal; After 6 transmissions of transmitted light beam process beam split eyeglass, become measuring beam and incide the measurement catoptron 7 that is placed on the measured object, after light beam process beam split eyeglass 6 transmissions that measurement catoptron 7 reflects, light intensity equates with the light intensity of the folded light beam of the beam split eyeglass 6 that forms reference beam, assemble by collimator objective 5, image on the ccd image sensor 3 after Amici prism 4 reflections, the spot center position that forms becomes measuring-signal, the angle drift value of light beam causes that reference signal and measuring-signal change simultaneously, autocollimation principle in conjunction with geometrical optics and optics, reference signal and measuring-signal are carried out the real-time differential processing of two dimension, the difference of the variable quantity of the spot center by asking for measuring-signal and reference signal can the dynamic compensation light beam the measurement of angle deviation that causes of angle drift value, accurately measure the variable quantity of the Bidimensional small angle of measuring catoptron 7:
θ=(d
1-d
0)/2f
Here: θ is the variable quantity of the Bidimensional small angle of measurement catoptron 7, d
1And d
0Be respectively the variable quantity of the spot center position that measuring-signal and reference signal form on ccd image sensor 3, f is the equivalent focal length of collimator objective 5.
The present invention passes through at the collimator objective 5 of 2 D photoelectric autocollimator and measures and place beam split eyeglass 6 between the catoptron 7, make full use of the optical texture of the differential improved properties 2 D photoelectric autocollimator of common light path, shine the collimated light beam of measuring catoptron 7 by collimator objective 5 and be divided into two bundles, form measuring beam and reference beam, change the angle drift value of light beam into common-mode error, the measurement of angle deviation that adopts error separating and dynamic compensation technology that this angle drift value is caused is eliminated and is suppressed.Wherein, referring to Fig. 6, beam split eyeglass 6 is coated with spectro-film 14 respectively by two surfaces of optical base-substrate 16 and anti-reflection film 15 constitutes, the beam split eyeglass is that the two sides of optical base-substrate is coated with spectro-film and anti-reflection film respectively, the surfaceness of optical base-substrate is better than 0.08um, the depth of parallelism on eyeglass two sides is less than 10 ", the splitting ratio of the spectro-film that plates is: 52/48≤T/R≤72/28, anti-reflection film requires transmitance factor alpha 〉=99%., when reducing optical energy loss, the measuring beam that assurance ccd image sensor 3 receives and the light intensity of reference beam equate.
As shown in Figure 2, in order to reduce optical energy loss, Amici prism 4 adopts polarization splitting prism 6, and in this case, the path of light is:
The light beam that light source 1 sends illuminates the graticule 2 on the focus that is positioned at collimator objective 5, become polarized light through polarization splitting prism 8 back transmitted light beams, transmitted light beam rotates 45 ° through λ/4 wave plates, the 9 rear polarizer polarisation of light directions that are placed between polarization splitting prism 8 and the collimator objective 5, becomes parallel collimated light beam through collimator objective 5 and incides the beam split eyeglass
6, light beam is divided into folded light beam and transmitted light beam: folded light beam is directly returned through former road, after collimator objective 5 convergences, λ/4 wave plates 9 make the polarization direction of polarized light rotate 45 ° again, become with light source 1 send through polarization splitting prism 8 and without the polarized light of the transmitted light beam quadrature of λ/4 wave plates, 9 rotatory polarization directions, know that by polarization characteristic light beam is again through reflection fully behind the polarization splitting prism 8, received by ccd image sensor 3, the spot center position of formation becomes reference signal; After 6 transmissions of transmitted light beam process beam split eyeglass, become measuring beam and incide the measurement catoptron 7 that is placed on the measured object, after light beam process beam split eyeglass 6 transmissions that measurement catoptron 7 reflects, light intensity equates with the light intensity of the folded light beam of the beam split eyeglass 6 that forms reference beam, assemble by collimator objective 5, in like manner, through also reflection fully behind λ/4 wave plates 9 and the polarization splitting prism 8, also image on the ccd image sensor 3 after the reflection, the spot center position that forms becomes measuring-signal, the angle drift value of light beam causes that reference signal and measuring-signal change simultaneously, autocollimation principle in conjunction with geometrical optics and optics, reference signal and measuring-signal are carried out the real-time differential processing of two dimension, the difference of the variable quantity of the spot center by asking for measuring-signal and reference signal can the dynamic compensation light beam the measurement of angle deviation that causes of angle drift value, accurately measure the variable quantity of the Bidimensional small angle of measuring catoptron 7:
θ=(d
1-d
0)/2f
Here: θ is the variable quantity of the Bidimensional small angle of measurement catoptron 7, d
1And d
0Be respectively the variable quantity of the spot center position that measuring-signal and reference signal form on ccd image sensor 3, f is the equivalent focal length of collimator objective 5.
Referring to Fig. 7 a and Fig. 7 b, the light source 1 in apparatus of the present invention can adopt laser instrument 17 or light emitting diode (LED) 18.
Referring to Fig. 8 a and Fig. 8 b, the graticule 2 in apparatus of the present invention can adopt the graticule 20 or the etching position 21 lighttight graticules 22 of etching position 19 printing opacities.
Describe method of the present invention below in detail:
For fear of measuring beam 11 and reference beam 10 because the problem that the hot spot that the light beam overlapping phenomenon causes receiving on the ccd image sensor 3 can't accurately be located need be adjusted beam split eyeglass 6, adjustment process is as follows:
Shown in Fig. 4 a, because beam split eyeglass 6 has guaranteed when making that eyeglass two surfaces are parallel, therefore after beam split eyeglass 6 rotates an angle, by the simple geometric optical principle as can be known the direction of the measuring beam 11 of outgoing can not change, but the direction of the reference beam 10 of reflection will change, shown in Fig. 4 b, in order to realize measuring hot spot 12 and with reference to the accurate location of hot spot 13, adjusting beam split eyeglass 6 makes the reference hot spot 13 and the measurement hot spot 12 that receive on the ccd image sensor 3 separate fully, adjusting the back will repeatedly be reflected in theory after through beam split eyeglass 6 and produce a plurality of pictures by measuring light beam that catoptron 7 reflects as can be known by the simple geometric optical principle, but in the reality because through beam split eyeglass 6 once more after the reflection, the energy of light is sharply decayed, make and on ccd image sensor 3, only receive a picture that brightness is faint, the fainter picture of remaining brightness of repeatedly reflecting can not be received by ccd image sensor 3, simultaneously owing to when carrying out the successive image processing, the faint picture of this brightness is not handled, thereby the influence that light beam repeatedly reflects generation can be ignored, beam split eyeglass 6 should be fixed after adjustment finished, then this device is calibrated, after the calibration this device in use beam split eyeglass 6 no longer adjust;
2. when measuring, as shown in Figure 1, the light beam that light source 1 sends illuminates the graticule 2 on the focus that is positioned at collimator objective 5;
3. this light beam is through behind the Amici prism 4, and transmitted light beam becomes parallel collimated light beam through collimator objective 5 and incides beam split eyeglass 6, and light beam is divided into folded light beam and transmitted light beam;
4. folded light beam is directly returned through former road, assembles through collimator objective 5, is received by ccd image sensor 3 by Amici prism 4 reflection backs, becomes reference signal;
5. after 6 transmissions of transmitted light beam process beam split eyeglass, become measuring beam and incide the measurement catoptron 7 that is placed on the measured object, after light beam process beam split eyeglass 6 transmissions that measurement catoptron 7 reflects, light intensity equates with the light intensity of the folded light beam of the beam split eyeglass 6 that forms reference beam, assemble by collimator objective 5, through imaging on the ccd image sensor 3 after Amici prism 4 reflections, become measuring-signal;
6. when measuring catoptron 7 generation small angle variation θ, the measuring-signal variable quantity is d
1', the angle drift value Δ d of while light beam
0Will cause the drift of measurement result, thereby the variable quantity of the measurement hot spot center that receives on the ccd image sensor 3 is d
1=d
1'+Δ d
0But, this angle drift value because the symmetry of the light channel structure of this measurement scheme and altogether the path difference dynamic characteristic be directly reflected as common-mode error, measuring-signal and reference signal will be drifted about simultaneously, be d with reference to the variable quantity of hot spot center
0=Δ d
0, thereby this angle drift value can and separate by reference signal monitoring, through the measurement of angle deviation that real-time differential processing can this angle drift value of dynamic compensation causes, the variable quantity d of the displacement of actual spot center is:
d=d
1-d
0=(d
1′+Δd
0)-Δd
0=d
1′
Can be in the hope of the Bidimensional small angle variable quantity θ that measures catoptron 7 accordingly:
θ=(d
1-d
0)/2f
Here: θ is the variable quantity of the Bidimensional small angle of measurement catoptron 7, d
1And d
0Be respectively the variable quantity of the spot center position that measuring-signal and reference signal form on ccd image sensor 3, f is the equivalent focal length of collimator objective 5.
As seen, in measurement result, reference signal and measuring-signal are carried out real-time differential processing, it is separable and the measurement of angle deviation that causes of the angle drift value of dynamic compensation light beam, improved measurement stability, repeatability and the uncertainty of measurement of 2 D photoelectric autocollimator, measured thereby this measurement scheme has realized high-precision Bidimensional small angle.
Embodiment 1:
As shown in Figure 1, at first adjust beam split eyeglass 6, make the reference hot spot 13 that receives on the ccd image sensor 3 with measure hot spot 12 and separate fully, avoid measuring beam 11 and reference beam 10 because the problem that the overlapping spot center that causes receiving on the ccd image sensor 3 of light beam can't accurately be located, beam split eyeglass 6 should be fixed after adjustment finished, then this device is calibrated, after the calibration this device in use beam split eyeglass 6 no longer adjust.When measuring, light source 1 adopts laser instrument 17, the light beam that sends illuminates the graticule 20 of etching position 19 printing opacities on the focus that is positioned at collimator objective 5, through behind the Amici prism 4, transmitted light beam becomes parallel collimated light beam through collimator objective 5 and incides beam split eyeglass 6, and light beam is divided into folded light beam and transmitted light beam: folded light beam is directly returned through former road, is assembled by collimator objective 5, Amici prism 4 reflection backs are received by ccd image sensor 3, and the spot center position of formation becomes reference signal; After 6 transmissions of transmitted light beam process beam split eyeglass, become measuring beam and incide the measurement catoptron 7 that is placed on the measured object, after light beam process beam split eyeglass 6 transmissions that measurement catoptron 7 reflects, light intensity equates with the light intensity of the folded light beam of the beam split eyeglass 6 that forms reference beam, assemble by collimator objective 5, image on the ccd image sensor 3 after Amici prism 4 reflections, the spot center position that forms becomes measuring-signal, the angle drift value of light beam causes that reference signal and measuring-signal change simultaneously, autocollimation principle in conjunction with geometrical optics and optics, reference signal and measuring-signal are carried out the real-time differential processing of two dimension, the difference of the variable quantity of the spot center by asking for measuring-signal and reference signal can the dynamic compensation light beam the measurement of angle deviation that causes of angle drift value, accurately measure the variable quantity of the Bidimensional small angle of measuring catoptron 7:
θ=(d
1-d
0)/2f
Here: θ is the variable quantity of the Bidimensional small angle of measurement catoptron 7, d
1And d
0Be respectively the variable quantity of the spot center position that measuring-signal and reference signal form on ccd image sensor 3, f is the equivalent focal length of collimator objective 5.
In the present embodiment, beam split eyeglass 6 is coated with spectro-film 14 respectively by two surfaces of optical base-substrate 16 and anti-reflection film 15 constitutes, optical base-substrate adopts 0 grade of optical glass, surfaceness is less than 0.03um, the depth of parallelism on eyeglass two surfaces is less than 3 "; the splitting ratio of the spectro-film that is plated is: T/R=62/38, anti-reflection film transmitance factor alpha=99.5%.Experimental result shows that this 2 D photoelectric autocollimation reaches 0.01 in measurement resolution " situation under, measurement stability is better than 0.05 "/h, uncertainty of measurement is better than 0.05 ", has realized the high precision two-dimensional narrow angle measurement.
Embodiment 2:
As shown in Figure 2, adopt polarized light to reduce the optical energy loss purpose to reach, at first adjust beam split eyeglass 6, make the reference hot spot 13 that receives on the ccd image sensor 3 with measure hot spot 12 and separate fully, avoided measuring beam 11 and reference beam 10 because the problem that the overlapping hot spot that causes receiving on the ccd image sensor 3 of light beam can't accurately be located, beam split eyeglass 6 should be fixed after adjustment finished, then this device is calibrated, after the calibration this device in use beam split eyeglass 6 no longer adjust.When measuring, light source 1 adopts laser instrument 17, the light beam that sends illuminates the graticule 20 of etching position 19 printing opacities on the focus that is positioned at collimator objective 5, become polarized light through polarization splitting prism 8 back light beams, transmitted light beam rotates 45 ° through λ/4 wave plates, the 9 rear polarizer polarisation of light directions that are placed between polarization splitting prism 8 and the collimator objective 5, become parallel collimated light beam through collimator objective 5 and incide beam split eyeglass 6, light beam is divided into folded light beam and transmitted light beam: folded light beam is directly returned through former road, after collimator objective 5 convergences, λ/4 wave plates 9 make the polarization direction of polarized light rotate 45 ° again, become with light source 1 send through polarization splitting prism 8 and without the polarized light of the transmitted light beam quadrature of λ/4 wave plates, 9 rotatory polarization directions, know that by polarization characteristic light beam is again through reflection fully behind the polarization splitting prism 8, received by ccd image sensor 3, the spot center position of formation becomes reference signal; After 6 transmissions of transmitted light beam process beam split eyeglass, become measuring beam and incide the measurement catoptron 7 that is placed on the measured object, after light beam process beam split eyeglass 6 transmissions that measurement catoptron 7 reflects, light intensity equates with the light intensity of the folded light beam of the beam split eyeglass 6 that forms reference beam, assemble by collimator objective 5, in like manner, through also reflection fully behind λ/4 wave plates 9 and the polarization splitting prism 8, also image on the ccd image sensor 3 after the reflection, the spot center position that forms becomes measuring-signal, the angle drift value of light beam causes that reference signal and measuring-signal change simultaneously, autocollimation principle in conjunction with geometrical optics and optics, reference signal and measuring-signal are carried out the real-time differential processing of two dimension, ask for the measurement of angle deviation that angle drift value that the difference of displacement of the spot center of measuring-signal and reference signal can the dynamic compensation light beam causes, accurately measure the variable quantity of the Bidimensional small angle of measuring catoptron 7:
θ=(d
1-d
0)/2f
Here: θ is the variable quantity of the Bidimensional small angle of measurement catoptron 7, d
1And d
0Be respectively the variable quantity of the spot center position that measuring-signal and reference signal form on ccd image sensor 3, f is the equivalent focal length of collimator objective 5.
In the present embodiment, beam split eyeglass 6 is coated with spectro-film 14 respectively by two surfaces of optical base-substrate 16 and anti-reflection film 15 constitutes, optical base-substrate adopts 0 grade of optical glass, surfaceness is less than 0.03um, the depth of parallelism on eyeglass two surfaces is less than 3 "; the splitting ratio of the spectro-film that is plated is: T/R=62/38, anti-reflection film transmitance factor alpha=99.5%.Experimental result shows, this 2 D photoelectric autocollimation reaches 0.01 in measurement resolution " situation under; measurement stability is better than 0.05 "/h, uncertainty of measurement is better than 0.05 ", realize also effectively having avoided when high precision two-dimensional narrow angle is measured because the unsettled shortcoming of light beam that light beam feedback laser instrument causes.
Embodiment 3:
As shown in Figure 1, light source 1 adopts light emitting diode (LED) 18, and the light beam that sends illuminates the graticule 20 of etching position 19 printing opacities on the focus that is positioned at collimator objective 5, and the miscellaneous part of present embodiment and principle of work are all identical with embodiment 1.
Embodiment 4:
As shown in Figure 2, light source 1 adopts light emitting diode (LED) 18, and the light beam that sends illuminates the graticule 20 of etching position 19 printing opacities on the focus that is positioned at collimator objective 5, and the miscellaneous part of present embodiment and principle of work are all identical with embodiment 2.
Embodiment 5:
As shown in Figure 1, light source 1 adopts laser instrument 17, and the laser beam that sends illuminates the etching position 21 lighttight graticules 22 on the focus that is positioned at collimator objective 5, and the miscellaneous part of present embodiment and principle of work are all identical with embodiment 1.
Embodiment 6:
As shown in Figure 2, light source 1 adopts laser instrument 17, and the laser beam that sends illuminates the etching position 21 lighttight graticules 22 on the focus that is positioned at collimator objective 5, and the miscellaneous part of present embodiment and principle of work are all identical with embodiment 2.
Embodiment 7:
As shown in Figure 1, light source 1 adopts light emitting diode (LED) 18, and the light beam that sends illuminates the etching position 21 lighttight graticules 22 on the focus that is positioned at collimator objective 5, and the miscellaneous part of present embodiment and principle of work are all identical with embodiment 1.
Embodiment 8:
As shown in Figure 2, light source 1 adopts light emitting diode (LED) 18, and the light beam that sends illuminates the etching position 21 lighttight graticules 22 on the focus that is positioned at collimator objective 5, and the miscellaneous part of present embodiment and principle of work are all identical with embodiment 2.