Dual-light-source high-precision anti-interference large-working-distance self-collimating device and method

A high-precision, dual-light source technology, applied in the direction of optical devices, measuring devices, optics, etc., can solve the problems of unstable beam transmission, measuring distance not too far, wave front distortion, etc., to increase anti-interference ability and improve anti-interference ability Effect of interference ability and improvement of measurement accuracy

Active Publication Date: 2019-04-05

HARBIN INST OF TECH

7 Cites 7 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0007] First, the use environment of the laser autocollimator should not be too harsh, otherwise the long-distance transmission of the beam in the air will make the beam transmission unstable, making the measurement results unstable, and the autocollimator cannot be used in an environment with more complex air conditions. Realize stable measurement;

[0008] Second, the measurement distance between the target reflector and the laser autocollimator should not be too ...

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Method used

Simultaneously, use double light source structure and place the optical filter of corresponding wavelength before detector, can effectively reduce the interference of another light source light beam and extraneous stray light, improve the signal-to-noise ratio of photoelectric sensor output signal, improve laser self- The measurement accuracy and anti-interference ability of the collimator.

Therefore the present invention is based on traditional laser autocollimator device structure, by measuring the light beam transmitted by the first dichroic mirror 54, this light beam can return the same way and does not include the yaw angle of combined reflector 5 And the pitch angle information, can realize the error caused by the angle drift and wavefront distortion caused by the measurement of air disturbance. The angle drift error can be measured through the angular drift feedback measurement unit 8 , and the error caused by the wave front distortion can be measured through the wave front distortion feedback measurement unit 9 , realizing separation and measurement of errors. Through the compensation algorithm, the error compensation of the yaw angle and pitch angle of the combined mirror 5 calculated by the imaging spot displacement information of the measuring beam is performed to reduce the influence of angle drift and wavefront distortion on the final measurement result, and make the measurement result more accurate. Accurate, improves the anti-interference ability of the instrument at the same working distance, and improves the measurement and compensation accuracy of the instrument.

[0068] The portable dual-light source high-precision, high-frequency response, anti-interference, and large workin...

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Abstract

The invention belongs to the technical field of precision measurement and the field of optical engineering, and particularly relates to a dual-light-source high-precision anti-interference large-working-distance self-collimating device and method. The device comprises a light source unit, a feedback imaging unit, a first transmission type collimating mirror, a sixth beam splitter mirror, a secondfilter, a combined mirror, an angle drift distance feedback measuring unit and a wavefront distortion feedback measuring unit. By means of the method, the angle drift distance feedback measuring unitand the wavefront distortion feedback measuring unit are additionally arranged, measurement and real-time compensation are carried out on the angle drift distance and wavefront distortion introduced by self-collimated beams due to air disturbance, influences of air disturbance on the self-collimated beams under the complex air environment and the long working distance are reduced, and the measurement and compensation accuracy is improved. By means of the device, under the same using environment and distance, the advantage of improving the measuring accuracy of the self-collimating device is achieved. In addition, the device adopts the structure of dual light sources, a light filter for correspondingly receiving the light beam wavelength is placed in front of a photoelectric detector, interference of the other light source and the external environment stray light on sensor detection is weakened, the signal-to-noise ratio of photoelectric sensor output signals is improved, and the measurement accuracy, the anti-interference ability and the stability of the laser self-collimating device are improved.

Application Domain

Angle measurementUsing optical means +1

Technology Topic

DistortionSignal-to-noise ratio (imaging) +14

Image

Examples

Experimental program(2)

Example Embodiment

Specific embodiment one

[0042] This embodiment is the first specific embodiment of a dual-light source high-precision anti-interference and large working distance self-collimation device.

[0043] The dual-light source high-precision anti-interference and large working distance self-collimation device in this embodiment has a schematic structural diagram as shown in figure 2 shown. The self-collimation device includes a light source unit 1, a feedback imaging unit 4, a first transmissive collimator mirror 2, a combined mirror 5, a sixth beam splitter 15, a second optical filter 16, and an angular drift feedback measurement unit 8 , and a wavefront distortion feedback measurement unit 9 .

[0044] The device includes a first light source 11 , a second light source 12 , a first dichroic mirror 54 , a first filter 44 , and a second filter 16 . The first light source 11 and the second light source 12 can emit light beams of two different wavelengths. The first dichroic mirror 54 presents high reflectivity to the light beam of the first light source 11, and presents high transmittance to the light beam of the second light source 12; the first filter 44 is the filter of the first light source 11, and can only The light beam of the wavelength of the first light source 11 passes through; the second filter 16 is a filter of the second light source 12 and can only pass the light beam of the wavelength of the second light source 12 .

[0045] The light source unit 1 is composed of a first light source 11 , a second light source 12 , and a fifth beam splitter 13 . The first light source 11 and the second light source 12 are located on both sides of the splitting section of the fifth beam splitter 13 and are located at the focal plane of the first transmissive collimator 2 . The first light source 11, the fifth beam splitter 13 and the first transmissive collimator 2 are placed in sequence, and the centers are on the same optical axis.

[0046] The combined reflector 5 includes a corner cube prism 53 and a first dichroic mirror 54 .

[0047] The feedback imaging unit 4 is arranged between the fifth beam splitter 13 and the first transmissive collimator 2, and the feedback imaging unit 4 includes a first feedback beam splitter 41, a first optical filter 44 and a first transmissive collimator. The first photoelectric sensor 42 at the focal plane of the collimating mirror 2; the light beam of the first light source 11 reflected by the first dichroic mirror 54 is a measuring beam, which is transmitted through the sixth beam splitter 15 and the first transmissive collimating mirror 2 successively 1. Reflected by the first feedback beam splitter 41, the imaging spot displacement information is collected by the first photoelectric sensor 42. When the reflection surface of the first dichroic mirror 54 is perpendicular to the optical axis, the focused spot is imaged at the center of the first photoelectric sensor 42 Location.

[0048] The sixth beam splitter 15 is arranged between the first transmissive collimator 2 and the combined reflector 5, and is close to the first transmissive collimator 2 side, and the second filter 16 is placed on the sixth beam splitter. Mirror 15 and the third feedback beam splitter 83.

[0049] The angular drift feedback measurement unit 8 is composed of a third feedback beam splitter 83, a second transmissive collimator 82, and a second photoelectric sensor 81 arranged on the focal plane of the second transmissive collimator 82, and the The optical axis of the unit is perpendicular to the detection center of the second photoelectric sensor 81 ; The fourth feedback mirror 92 is fixed on the angle adjustment unit 93 ; the optical axis of the unit is perpendicular to the center of the detection plane of the third wavefront sensor 91 . The angular drift feedback measurement unit 8 and the wavefront distortion feedback measurement unit 9 together form a disturbance feedback measurement unit.

[0050] The measurement principle of the present embodiment is as follows:

[0051] The light beam emitted by the light source 11 and the light beam emitted by the light source 12 will merge after passing through the fifth beam splitter 13. The optical axes of the two beams coincide and the propagation directions are the same. Collimated into parallel light. After the parallel light is transmitted through the sixth beam splitter, it is incident on the reflective surface of the first dichroic mirror 54 of the combined reflector 5. At this time, the light beam of the first light source 11 will be reflected as the measuring beam; the light beam of the second light source 12 will be transmitted, as a reference beam.

[0052] The reflected light beam is the measurement light beam, and the propagation direction changes, so it will be transmitted through the sixth beam splitter 15, transmitted through the first transmissive collimator 2, reflected by the first feedback beam splitter 41, transmitted through the first filter 44, and incident on the first beam splitter. The photoelectric sensor 42 collects imaging spot displacement information Δx1 and Δy1 . The yaw angle and pitch angle of the combined reflector and the measured object are Δθ1=f1(Δx1), Among them, f1 and f2 are two functions.

[0053] The transmitted beam is the reference beam, which is transmitted by the first dichroic mirror 54 , continues to propagate forward, is reflected by the corner cube prism 53 , and is transmitted by the first dichroic mirror 54 in sequence. It can be seen from the reflection characteristics of the corner cube that the propagation direction of the light beam is opposite to the original direction and has nothing to do with the deflection angle of the combined reflector 5 . It is reflected by the sixth beam splitter 15, transmitted by the second filter 16, and enters the disturbance feedback measurement unit.

[0054] The light beam will be divided into two reference beams after passing through the third feedback beam splitter 83: one is a reflected reference beam, which is transmitted through the second transmissive collimator 82 and converged on the second photoelectric sensor 81 to collect imaging spot displacement information Δx2 and Δy2 The other way passes through the third feedback beamsplitter 83 to split and transmit the reference beam, which is reflected by the fourth feedback beamsplitter 92 and incident on the third wavefront sensor 91 to collect the reference beam wavefront information w0; meanwhile, the angle adjustment unit 93 drives the first An angle deflection driver 931 and a second angle deflection driver 932 adjust the angle of the fourth feedback beam splitter 92 so that the light beam is incident on the third wavefront sensor 91. At this time, the wavefront information w1 of the reference beam is remeasured to avoid angular drift The influence of the overall tilt of the wavefront caused by the wavefront on the measurement of wavefront distortion. The yaw angle and pitch angle Δθ=f3(Δθ1, Δx2, w1) of the combined reflector 5 and the surface of the measured object can be obtained by calculation, f3 and f4 represent two functions.

[0055] The measurement steps of the present embodiment are as follows:

[0056] Step a, placing the combined reflector 5 on the object to be measured, aligning the laser autocollimator with the reflective surface of the first dichroic mirror 54 of the combined reflector 5;

[0057] Step b. Turn on the light source unit 1, and feed back the imaging unit 4 to work, if:

[0058] (1) If the spot imaging is outside the detection area of the first photoelectric sensor 42, adjust the position and direction of the laser autocollimator so that the spot imaging is within the detection area of the first photoelectric sensor 42, and enter step c;

[0059] (2) If the spot imaging is within the detection area of the first photoelectric sensor 42, enter step c;

[0060] Step c, feed back the imaging unit 4 to work, obtain the displacement information Δx1 and Δy1 of the off-center measurement beam imaging spot on the first photoelectric sensor 42, the yaw angle and the pitch angle of the combined reflector 5 and the measured object are Δθ1=f1( Δx1), Among them, f1 and f2 represent two functions.

[0061] Step d, the disturbance feedback measurement unit works, and obtains the displacement information Δx2 and Δy2 of the off-center reference beam imaging spot on the second photoelectric sensor 81 of the angular drift feedback measurement unit 8, and obtains the third wave in the wavefront distortion feedback measurement unit 9 The reference beam wavefront data w0 measured by the front sensor 91;

[0062] Step e, according to Δx2, Δy2, and w0, use the angle adjustment unit 93 to drive the first angle deflection driver 931 and the second angle deflection driver 932, so that the light beam reflected by the fourth feedback mirror 92 is vertically incident on the third wavefront sensor 91, again Obtain the reference beam wavefront data w1 measured by the third wavefront sensor 91;

[0063] Step f, according to Δθ1, Δx2, Δy2 and w1, calculate the yaw angle and pitch angle Δθ and Among them, Δθ=f3(Δθ1,Δx2,w1), f3 and f4 represent two functions.

[0064] It should be noted that, according to the structure and measurement principle of the traditional laser autocollimator device, by using the displacement information Δx1 and Δy1 of the imaging spot of the measurement beam reflected by the first dichroic mirror 54, the combined reflector 5 can be calculated. The yaw and pitch angles Δθ1 and However, when the laser autocollimator works in a large working distance and in a non-ideal air environment in the laboratory, due to the existence of air disturbance, the measurement beam not only contains the measured angle information, but also contains angle drift and beam wavefront distortion information. It will cause errors in the measurement results and affect the measurement stability and measurement accuracy of the instrument.

[0065] Therefore, on the basis of the traditional laser autocollimator device structure, the present invention measures the light beam transmitted by the first dichroic mirror 54, the light beam will return the same way and does not include the yaw angle and the pitch angle of the combined reflector 5 Information can be used to measure the angle drift caused by air disturbance and the error caused by wavefront distortion. The angle drift error can be measured through the angular drift feedback measurement unit 8 , and the error caused by the wave front distortion can be measured through the wave front distortion feedback measurement unit 9 , realizing separation and measurement of errors. Through the compensation algorithm, the error compensation of the yaw angle and pitch angle of the combined mirror 5 calculated by the imaging spot displacement information of the measuring beam is performed to reduce the influence of angle drift and wavefront distortion on the final measurement result, and make the measurement result more accurate. Accurate, improves the anti-interference ability of the instrument at the same working distance, and improves the measurement and compensation accuracy of the instrument.

[0066] At the same time, using a dual light source structure and placing a filter corresponding to the wavelength in front of the detector will effectively reduce the interference of another light source beam and external stray light, improve the signal-to-noise ratio of the output signal of the photoelectric sensor, and improve the laser autocollimator. Excellent measurement accuracy and anti-interference ability.

Example Embodiment

Specific embodiment two

[0067] This embodiment is the second specific embodiment of a portable dual-light source high-precision high-frequency response anti-interference large working distance self-collimation device.

[0068] The portable dual-light source high-precision, high-frequency response, anti-interference, and large working distance self-collimation device in this embodiment, the structural diagram is as follows Figure 4 shown. On the basis of the specific embodiment 1, the first optical filter 44, the sixth beam splitter 15, the second optical filter 16, the second transmissive collimator 82, the fourth feedback beam splitter 92, and the angle adjustment unit 93 are removed , adding the second dichroic mirror 14 and the third transmissive collimator mirror 94. The optical path structure of the disturbance feedback measurement unit is adjusted, the volume of the optical path and optical components is reduced, the overall structure is compact and stable, and it has more advantages of portability design. At the same time, the software algorithm replaces the mechanical adjustment and alignment link, improves the measurement speed, and makes the laser autocollimator have the advantage of high frequency response.

[0069] The self-collimation device of this embodiment includes a light source unit 1, a feedback imaging unit 4, a first transmissive collimator mirror 2, a combined mirror 5, a second dichroic mirror 14, an angular drift feedback measurement unit 8, and Wavefront distortion feedback measurement unit 9 .

[0070] The device includes a first light source 11 , a second light source 12 , a first dichroic mirror 54 , and a second dichroic mirror 14 . The first light source 11 and the second light source 12 can emit light beams of two different wavelengths. The first dichroic mirror 54 presents high reflectivity to the first light source 11, and presents high transmittance to the second light source 12; the second dichroic mirror 14 presents high transmittance to the first light source 11, and presents high transmittance to the second light source 12. 12 exhibits high reflectivity.

[0071] The light source unit 1 is composed of a first light source 11 , a second light source 12 , and a fifth beam splitter 13 . The first light source 11 and the second light source 12 are located on both sides of the splitting section of the fifth beam splitter 13 and are located at the focal plane of the first transmissive collimator 2 . The first light source 11, the fifth beam splitter 13 and the first transmissive collimator 2 are placed in sequence, and the centers are on the same optical axis.

[0072] The combined reflector 5 includes a corner cube prism 53 and a first dichroic mirror 54 .

[0073] The feedback imaging unit 4 is arranged between the fifth beam splitter 13 and the first transmissive collimator 2, the feedback imaging unit includes the first feedback beam splitter 41 and the focal plane of the first transmissive collimator 2 The first photoelectric sensor 41; the light beam of the first light source 11 reflected by the first dichroic mirror 54 is a measuring beam, which is transmitted through the first transmissive collimator mirror 2, reflected by the first feedback beam splitter 41, and passed through the second dichroic mirror 41. The color mirror 14 transmits, and the imaging spot displacement information is collected by the first photoelectric sensor 42 . When the reflection surface of the first dichroic mirror 54 is perpendicular to the optical axis, the converging spot is imaged at the center of the first photoelectric sensor 42 .

[0074] The angular drift feedback measurement unit 8 is composed of a third feedback beam splitter 83 and a second photoelectric sensor 81 . The second photoelectric sensor 81 is arranged on the focal plane of the first transmissive collimator 2 where the third feedback beam splitter 83 beam splitting beams converge; the wavefront distortion feedback measurement unit 9 consists of the third transmissive collimator 94 and the third wave The front sensor 91 is composed. The angular drift feedback measurement unit 8 and the wavefront distortion feedback measurement unit 9 jointly constitute a disturbance feedback measurement unit.

[0075] The second dichroic mirror 14 is arranged between the first feedback beam splitter 41 and the first photoelectric sensor 42, and is placed obliquely at an angle of 45°. The third feedback beam splitter 83, the third transmissive collimator 94, and the third wavefront sensor 91 are arranged in sequence, and the center is on the optical axis of the light beam reflected by the second dichroic mirror 14, and the third transmissive collimator 94 The focal plane of the first transmissive collimating mirror 2 coincides with the focal plane, and the two collimating mirrors are on the same side of the focal plane.

[0076] The measurement principle of the present embodiment is as follows:

[0077] The light beam emitted by the first light source 11 and the light beam emitted by the second light source 12 will merge after passing through the fifth beam splitter 13. The collimating mirror 2 collimates into parallel light. Parallel light is incident on the reflective surface of the first dichroic mirror 54 of the combined reflector 5. At this time, the beam of the first light source 11 will be reflected as the measuring beam; the beam of the second light source 12 will be transmitted as the reference beam.

[0078] The reflected light beam is the measurement light beam, and the propagation direction changes, so it will return to pass through the first transmissive collimator 2, the first feedback beamsplitter 41, the second dichroic mirror 14, and then incident on the first photoelectric sensor 42 for collection. Imaging spot displacement information Δx1 and Δy1; the yaw angle and the pitch angle of the combined reflector 5 and the measured object are Δθ1=f1(Δx1), Among them, f1 and f2 represent two functions.

[0079] The transmitted beam is the reference beam, which continues to propagate forward, and is reflected by the corner cube prism 53 and transmitted by the first dichroic mirror 54 in sequence. It can be seen from the reflection characteristics of the corner cube that the propagation direction of the light beam is opposite to the original direction and has nothing to do with the deflection angle of the combined reflector 5 . At the same time, because the light beam is transmitted through the first dichroic mirror 54, the light beam is mainly composed of the light beam of the second light source. Therefore, as a reference beam, the light beam will be transmitted by the first transmissive collimator 2 and reflected by the first feedback beam splitter 41 , and then reflected by the second dichroic mirror 14 to enter the disturbance feedback measurement unit.

[0080] The reference beam will be split and reflected by the third feedback beam splitter 83 first, incident and converged on the second photoelectric sensor 81, and the second photoelectric sensor 81 collects imaging spot displacement information Δx2 and Δy2; The transmitted reference beam is collimated into parallel light by the third transmissive collimator 94, and enters the third wavefront sensor 91 to collect the wavefront distortion information w0 of the reference beam. Through the obtained Δx2, Δy2, w0, use software to solve and separate the overall tilt of the wavefront, obtain the wavefront distortion data of the reference beam, and re-measure to obtain the wavefront distortion information w1, which can avoid the overall tilt of the wavefront caused by angular drift The impact on the measurement of wavefront distortion; where w1 = f3 (Δx2, Δy2, w0), f3 represents a function. The yaw angle and pitch angle Δθ=f4(Δθ1, Δx2, w1) of the combined reflector 5 and the surface of the measured object can be obtained by calculation, f4 and f5 represent two functions.

[0081] The measurement steps of the present embodiment are as follows:

[0082] Step a, placing the combined reflector 5 on the object to be measured, aligning the laser autocollimator with the reflective surface of the first dichroic mirror 54 of the combined reflector 5;

[0083] Step b. Turn on the light source unit 1, and feed back the imaging unit device to work, if:

[0084] (1) If the spot imaging is outside the detection area of the first photoelectric sensor 42, adjust the position and direction of the laser autocollimator so that the spot imaging is within the detection area of the first sensor 42, and enter step c;

[0085] (2) If the spot imaging is within the detection area of the first photoelectric sensor 42, enter step c;

[0086] Step c, feed back the imaging unit 4 to work, and obtain the displacement information Δx1 and Δy1 of the off-center measurement beam imaging spot on the first photoelectric sensor 42; the yaw angle and the pitch angle of the combined reflector 5 and the measured object are Δθ1=f1( Δx1), Among them, f1 and f2 represent two functions.

[0087] Step d, the disturbance feedback measurement unit works, and obtains the displacement information Δx2 and Δy2 of the off-center reference beam imaging spot on the second photoelectric sensor 81 of the angular drift feedback measurement unit 8, and obtains the third wave in the wavefront distortion feedback measurement unit 9 The reference beam wavefront data w0 measured by the front sensor 91;

[0088] Step e, according to Δx2, Δy2, and w0, use software to calculate the wavefront distortion data, compensate the overall tilt of the reference beam, and recalculate the reference beam wavefront distortion information w1, where w1=f3(Δx2, Δy2, w0), f3 represents a function;

[0089] Step f, according to Δθ1, Δx2, Δy2 and w1, calculate the yaw angle and pitch angle Δθ and Among them, Δθ=f4(Δθ1,Δx2,w1), f4 and f5 represent two functions.

[0090] What needs to be supplemented for above embodiment is:

[0091] First, the disturbance feedback measurement unit is added on the basis of the traditional laser autocollimator structure to realize the measurement of beam angle drift and wavefront distortion information caused by air disturbance. Using the idea of error separation, the disturbance feedback measurement unit measures the measurement errors caused by air disturbances according to the formation mechanism and detection method, which can realize accurate measurement and compensation of measurement error. The disturbance feedback measurement unit can reduce the influence of air disturbance and other environmental factors on the measurement results of the laser autocollimator, and significantly improve the measurement accuracy, stability, and measurement distance of the laser autocollimator.

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Classification and recommendation of technical efficacy words

Improve anti-interference ability
Reduce the impact

Dual-light-source high-precision anti-interference large-working-distance self-collimating device and method

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Image

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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