CN105043241A - Contrast type anti-interference corner reflector laser interferometer, calibration method and measurement method - Google Patents

Abstract

The invention discloses a contrast type anti-interference corner reflector laser interferometer, a calibration method and a measurement method. The contrast type anti-interference corner reflector laser interferometer comprises a laser source, a fixed corner reflector, an interference measurement photoelectric detector, a movable corner reflector and a beam splitter group. The contrast type anti-interference corner reflector laser interferometer is characterized by further comprising a reflection measurement photoelectric detector. A laser beam is reflected to the beam splitter group through the movable corner reflector and then forms a reflected laser beam, and the reflected laser beam shoots to the reflection measurement photoelectric detector. According to the laser interferometer disclosed by the invention, the reflection measurement photoelectric detector can measure the intensity of the laser beam reflected by the movable corner reflector, and the interference state of a laser interference beam is determined according to the intensity of the reflected laser beam, thereby realizing a purpose of resisting environmental interference.

Description

A comparative anti-interference corner mirror laser interferometer, calibration method and measurement method

technical field

The invention relates to the field of precision testing technology and instruments, in particular to a contrasting anti-interference angle reflector laser interferometer, a calibration method and a measurement method.

Background technique

The emergence of lasers has enabled the rapid development of ancient interferometric technology. Lasers have the characteristics of high brightness, good directionality, monochromaticity and good coherence. Laser interferometry technology has been relatively mature. Laser interferometry system is widely used: measurement of precision length and angle, such as detection of linear scale, grating, gauge block, and precision screw; positioning detection system in precision instruments, such as control and correction of precision machinery; special purpose for large-scale integrated circuits Positioning detection systems in equipment and testing instruments; measurement of tiny dimensions, etc. At present, Michelson interferometers or similar optical path structures are used in most laser interferometric length measurement systems, for example, single-frequency laser interferometers commonly used at present.

The single-frequency laser interferometer is the beam emitted from the laser, which is divided into two paths by the beam splitter after beam expansion and collimation, and reflected from the fixed mirror and the movable mirror respectively to meet on the beam splitter to generate interference fringes. When the movable mirror moves, the light intensity change of the interference fringe is converted into an electric pulse signal by the photoelectric conversion element and electronic circuit in the receiver, and after being shaped and amplified, it is input to the reversible counter to calculate the total pulse number N, and then the electronic The computer calculates the displacement L of the movable mirror according to the calculation formula L=N×λ/2, where λ is the laser wavelength.

In actual use, the inventor of the present application found that the above-mentioned measurement structure and measurement method still have deficiencies:

The current single-frequency laser interferometer still has the problem of being seriously affected by the environment. When the movable mirror of the laser interferometer moves, the light intensity changes of the interference fringes are converted into electrical pulse signals by the photoelectric conversion elements and electronic circuits in the receiver. When it is the strongest constructive interference, the signal exceeds the trigger level of the counter and is recorded. If the environment changes, such as air turbulence, increased impurities in the air, machine tool oil mist, and the impact of cutting chips during processing on the laser beam, making The intensity of the laser beam decreases. At this time, even the strongest constructive interference occurs, and the intensity may be lower than the trigger level of the counter and not be counted.

Therefore, based on the above shortcomings, there is an urgent need for a laser interferometer that can resist environmental interference and improve measurement accuracy.

Contents of the invention

The object of the present invention is to provide a laser interferometer capable of resisting environmental interference to solve the deficiency of the existing laser interferometer in its ability to resist environmental interference.

In order to realize the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A contrasting anti-interference angle reflector laser interferometer, comprising a laser source, a fixed angle reflector, an interferometric photodetector, a moving angle reflector and a beam splitter group, the laser beam emitted by the laser source passes through the beam splitter After the mirror group is divided into the first laser beam and the second laser beam, the first laser beam shoots to the fixed angle reflector, is reflected by the fixed angle reflector and then shoots to the beam splitter group again, and then passes through the beam splitter After being grouped, it shoots to the interferometric photodetector, and the second laser beam shoots to the moving angle reflector, and then shoots to the beam splitter group after being reflected by the moving angle mirror, and then shoots to the beam splitter group after passing through the beam splitter group. In the interferometric photodetector, the first laser beam and the second laser beam interfere when they are directed to the interferometric photodetector, and the laser interferometer also includes a reflection measurement photodetector, and the second laser beam After the beam is irradiated to the spectroscope group by the moving angle reflector, a reflected laser beam is also formed, and the reflected laser beam is irradiated to the reflection measurement photodetector.

As a further preferred solution, the beam splitter group includes a first beam splitter and a second beam splitter, the laser beam emitted by the laser source first hits the first beam splitter, and is reflected by the first beam splitter to form the first laser beam , is transmitted through the first beam splitter to form a second laser beam, the first laser beam shoots to the fixed angle reflector, is reflected and shoots to the first beam splitter again, and then transmits through the first beam splitter, The second laser beam shoots to the moving angle reflector, is reflected by the moving angle reflector and then shoots to the second beam splitter, and is transmitted by the second beam splitter and then shoots to the first beam splitter , and interferes with the first laser beam transmitted from the first beam splitter to form an interference beam and then shoot to the interferometric photodetector, and shoot to the second beam splitter from the moving angle reflector The second laser beam is also reflected by the second beam splitter to form the reflected laser beam.

In the laser interferometer of the present application, since the reflection measurement photodetector can measure the intensity of the laser beam reflected by the moving corner reflector, the interference state of the laser interference beam can be determined according to the intensity of the reflected laser beam, so as to achieve the purpose of anti-environmental interference.

As a further preferred solution, the laser beam between any two of the laser source, the fixed-angle reflector, the interferometric photodetector, the beam splitter group, and the reflection measurement photodetector is arranged in a closed space without contact with the outside Environmental space contact. In this application, the laser beam between any two components of the laser source, fixed-angle mirror, interferometric photodetector, spectroscopic mirror group, and reflection measurement photodetector is set in a closed space, so that during the measurement process Among them, the laser beam between the above-mentioned components will not be affected by environmental factors, thereby ensuring the measurement accuracy of the laser interferometer of the present application.

As a further preferred solution, the laser beam between the beam splitter group and the moving corner mirror is exposed to ambient air. In actual use, the moving angle reflector is set on the measured object and moves with the measured object, so in this application, the laser beam between the beam splitter group and the moving angle reflector is exposed to the ambient air, first This makes the structure of the laser interferometer of the present application simple, and at the same time facilitates the arrangement of the laser interferometer of the present application.

The application also discloses a calibration method for the above-mentioned laser interferometer structure,

A method for calibrating a laser interferometer with a contrasting anti-interference corner mirror, comprising the following steps:

Step 1. Position adjustment: adjust the positions of the laser source, fixed angle reflector, beam splitter group, interferometric photodetector, reflection measurement photodetector and moving angle reflector;

Step 2, adjust the optical path: start the laser source, and further accurately adjust the positions of the fixed angle reflector, the beam splitter group, the interferometric photodetector, the reflection measurement photodetector and the moving angle reflector, so that the optical path of the laser interferometer reaches Design requirements;

Step 3, generate the strongest interference database: move the movable corner reflector in an environment with clean air, and fix the movable corner reflector when the interference beam directed at the interferometric photodetector is the strongest constructive interference , record the reflection measurement photodetector readings and the interferometric photodetector readings at this time, change the air environment to change the reflection measurement photodetector readings, and record several reflection measurement photodetector readings and corresponding interferometric photodetectors at the same time readings to obtain the strongest interference database.

The laser interferometer structure and calibration method of the present application, when the strongest constructive interference, change the measurement environment, record the reflection measurement photodetector readings and interferometric photodetector readings to form the strongest interference database, in the actual measurement process, if When the interferometric photodetector cannot normally detect the strongest constructive interference due to environmental factors, the readings of the reflectance photodetector and the interferometric photodetector can be compared with the data in the strongest interference database. If there is matching data, then this position is the strongest constructive interference, which enables the laser interferometer of the present application to achieve the ability to resist environmental interference.

As a further preferred solution, the calibration method of the present application also includes step 4, generating the weakest interference database: moving the moving angle reflector in a clean air environment, when the interference beam directed at the interferometric photodetector For the weakest destructive interference, fix the moving angle reflector, record the reflection measurement photodetector readings and interferometric photodetector readings at this time, change the air environment to make the reflection measurement photodetector readings change, and record several The reflection measurement photodetector readings and the corresponding interferometric photodetector readings are obtained to obtain the weakest interference database.

As a further preferred solution, it also includes step 5, generating a 1/n wavelength interference database, where n is a positive integer greater than or equal to 2: moving the movable angle reflector in an air-clean environment, when shooting at the interference When the interference beam of the measurement photodetector is the strongest constructive interference, continue to move the distance of 1/2n wavelength, record the readings of the reflection measurement photodetector and the interferometric photodetector at this time, and then change the air environment to make the reflection Measure the reading change of the photodetector, and record the readings of several reflection measurement photodetectors and the corresponding interferometric photodetector readings at the same time to obtain the 1/n wavelength interference database.

When two laser beams interfere, the optical path difference between the adjacent strongest constructive interference and the weakest destructive interference is half a wavelength. In the calibration method of this application, for the strongest constructive interference, the weakest Both destructive interference and 1/n wavelength interference have been calibrated, that is to say, when the laser interferometer of the present application is used for actual measurement, the readings of the photodetector for reflection measurement and the reading of the interferometric photodetector can be compared with the strongest interference The data in the database, the weakest interference database, and the 1/n wavelength interference database are compared, and it is determined whether the position is the strongest constructive interference, the weakest destructive interference or 1/n wavelength interference according to the matching of the data. This makes the laser interferometer of the present application not only resistant to environmental interference, but also improves measurement accuracy.

The invention also discloses a measurement method using the above-mentioned laser interferometer and calibration method,

A measurement method using the above-mentioned comparative anti-interference corner mirror laser interferometer and the above-mentioned calibration method:

In the actual measurement environment, assume that the signal reading measured by the reflection measurement photodetector is x, and the signal reading obtained by the interferometric photodetector measurement is y, and the x value and the y value are in the strongest interference database, the most Weak interference database and 1/n wavelength interference database are compared. When the x value and y value match a certain set of values in the strongest interference database, this position is considered as the strongest constructive interference position. When the x value and y values match a set of values in the weakest interference database, then this position is considered as the weakest destructive interference position, when the x and y values match a set of values in the 1/n wavelength interference database , then this position is considered to be the 1/n wavelength interference position.

In the measurement method of the present application, the interference condition of the current interference beam is determined through the x value and the y value, so as to realize the ability of resisting environmental interference and improve the measurement accuracy at the same time.

As a further preferred solution, the matching threshold △ of the y value is set, and the value corresponding to the interferometric photodetector in the strongest interference database, the weakest interference database, and the 1/n wavelength interference database is set to y'. The strong interference database, the weakest interference database, and the 1/n wavelength interference database carry out the query of y', if there is y' so that |y-y'|<△, and then distinguish the database where y' is located, if y' is in the strongest interference In the database, this position is considered as the strongest constructive interference position. If y' is in the weakest interference database, this position is considered as the weakest destructive interference position. If y' is in the 1/n wavelength interference database, then This position is considered to be a 1/n wavelength interference position.

As a further preferred solution, set the value corresponding to the reflectance measurement photodetector in the strongest interference database, the weakest interference database, and the 1/n wavelength interference database as x', and in actual measurement, select x that is closest to the actual measured value x 'As a matching value, query y' from the strongest interference database, the weakest interference database, and 1/n wavelength interference database according to the value of x', if there is y' such that |y-y'|<△, then distinguish y' If y' is in the strongest interference database, this position is considered as the strongest constructive interference position, if y' is in the weakest interference database, this position is considered as the weakest destructive interference position, if y 'In the 1/n wavelength interference database, this position is considered to be the 1/n wavelength interference position.

As a further preferred solution, the size of the matching threshold Δ ensures that when performing data query, y' is a unique value when |y-y'|<Δ is satisfied. When the matching threshold △ is large, a set of x values and y values may match two or more sets of x' and y' values, which brings inconvenience to the measurement, so the threshold △ should be matched first, so that during the measurement A set of x and y values matches at most a set of x' and y' values for easy measurement.

As a further preferred solution, the size of the matching threshold △ is set according to the accuracy requirements of the actual measurement. When a high-precision measurement value is required, a smaller matching threshold is used. When a high-precision measurement value is not required, a higher matching threshold is used. Large matching threshold.

As a further preferred solution, set Δ=5%.

In the measurement method of the present application, by setting the matching threshold △, the size of the matching threshold △ is set according to the needs of the actual measurement accuracy, so as to facilitate the matching selection of data during the measurement process and reduce the difficulty of measurement.

Compared with prior art, the beneficial effect of the present invention:

By setting the reflection measurement photodetector, after the laser interferometry environment changes, the laser intensity reflected by the moving angle mirror can be measured. The laser interference state is no longer directly determined by the signal size of the interferometry photodetector, but by the reflection The measurement photodetector and the interferometric photodetector are jointly determined, which can greatly improve the anti-interference ability of the laser interferometer.

Beneficial effects of other embodiments of the present application:

The laser interferometer of the present application can not only determine the position of the strongest constructive interference, but also can determine the position of the weakest destructive interference and the 1/n wavelength interference position, so that the laser interferometer of the present application can not only resist the environment interference, but also improve the measurement accuracy.

Description of drawings:

Fig. 1 is the optical path schematic diagram of laser interferometer structure of the present invention,

Marked in the figure:

1-laser source, 2-fixed angle mirror, 3-moving angle mirror, 4-interferometric photodetector, 5-beam splitter group, 6-reflection measurement photodetector, 7-first laser beam, 8- The second laser beam, 9-reflected laser beam, 51-first beam splitter, 52-second beam splitter.

Detailed ways

The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

Embodiment 1, the comparative type anti-interference angle mirror laser interferometer, includes a laser source 1, a fixed angle mirror 2, an interferometric photodetector 4, a moving angle mirror 3 and a beam splitter group 5, and the laser source 1 The emitted laser beam is divided into a first laser beam 7 and a second laser beam 8 after the beam splitter group 5, and the first laser beam 7 shoots to the fixed-angle reflector 2 and is reflected by the fixed-angle reflector 2 Then shoot to the beam splitter group 5 again, and then shoot to the interferometric photodetector 4 after the beam splitter group 5, and the second laser beam 8 shoots to the moving angle reflector 3, and is reflected by the moving angle After being reflected by the mirror 3, it shoots to the beam splitter group 5 again, and then shoots to the interferometric photodetector 4 after passing through the beam splitter group 5, and the first laser beam 7 and the second laser beam 8 shoot to the interferometric photoelectric detector When the detector 4 interferes, the laser interferometer also includes a reflection measurement photodetector 6, and the second laser beam 8 also forms a A reflected laser beam 9 is directed towards the reflection measurement photodetector 6 .

As a preferred solution of this embodiment, the beam splitter group 5 includes a first beam splitter 51 and a second beam splitter 52, the laser beam emitted by the laser source 1 first hits the first beam splitter 51, and passes through the first beam splitter Mirror 51 reflects to form the first laser beam 7, which is transmitted by the first beam splitter 51 to form the second laser beam 8, and the first laser beam 7 shoots to the fixed angle reflector 2, and then shoots to the first beam splitter again after being reflected. Mirror 51, and then transmitted through the first beam splitter 51, the second laser beam 8 shoots to the moving angle reflector 3, and then shoots to the second beam splitter after being reflected by the moving angle mirror 3 52, transmits through the second beam splitter 52 and shoots to the first beam splitter 51, and interferes with the first laser beam 7 transmitted from the first beam splitter 51 to form an interference beam and shoots to the first laser beam 7 The interferometric photodetector 4, the second laser beam 8 emitted by the moving angle mirror 3 to the second beam splitter 52 is also reflected by the second beam splitter 52 to form the reflected laser beam 9 .

In the laser interferometer of this embodiment, since the reflection measurement photodetector 6 can measure the intensity of the laser beam reflected by the moving corner reflector 3, the interference state of the laser interference beam can be determined according to the intensity of the reflected laser beam, so as to achieve the purpose of anti-environmental interference.

As a further preferred solution, the laser beam between any two of the laser source 1, the fixed-angle reflector 2, the interferometric photodetector 4, the beam splitter group 5, and the reflection measurement photodetector 6 is arranged in a closed space within without contact with the external environment. In the present application, the laser beam between any two of these components, the laser source 1, the fixed-angle reflector 2, the interferometric photodetector 4, the beam splitter group 5, and the reflection measurement photodetector 6, is arranged in a closed space, so that During the measurement process, the laser beams between the above components will not be affected by environmental factors, thereby ensuring the measurement accuracy of the laser interferometer of the present application.

As a further preferred solution, the laser beam between the beam splitter group 5 and the moving corner mirror 3 is exposed to ambient air. In actual use, the moving angle reflector 3 is arranged on the measured object and moves with the measured object, so in this application, the laser beam between the beam splitter group 5 and the moving angle reflecting mirror 3 is exposed to the ambient air Among them, first of all, it makes the structure of the laser interferometer of the present application simple, and at the same time facilitates the arrangement of the laser interferometer of the present application.

Embodiment 2, for the calibration method of above-mentioned laser interferometer structure,

A method for calibrating a laser interferometer with a contrasting anti-interference corner mirror, comprising the following steps:

Step 1. Position adjustment: adjust the positions of laser source 1, fixed angle reflector 2, beam splitter group 5, interferometric photodetector 4, reflection measurement photodetector 6 and moving angle reflector 3;

Step 2, adjusting the optical path: start the laser source 1, and further accurately adjust the positions of the fixed angle reflector 2, the beam splitter group 5, the interferometric photodetector 4, the reflection measurement photodetector 6 and the moving angle reflector 3, so that The optical path of the laser interferometer meets the design requirements;

Step 3, generate the strongest interference database: move the moving angle reflector 3 in an environment with clean air, and fix the moving angle when the interference beam directed at the interferometric photodetector 4 is the strongest constructive interference The reflection mirror 3 records the readings of the reflective measurement photodetector 6 and the readings of the interferometric photodetector 4 at this time, changes the air environment to make the readings of the reflective measurement photodetector 6 change, and simultaneously records the readings of several reflective measurement photodetectors 6 and The corresponding interferometric photodetector 4 readings are obtained to obtain the strongest interferometric database.

The laser interferometer structure and calibration method of this embodiment, when the strongest constructive interference, change the measurement environment, record the readings of the reflection measurement photodetector 6 and the readings of the interferometric photodetector 4 to form the strongest interference database, in the actual measurement process In, if the interferometric photodetector 4 cannot normally detect the strongest constructive interference due to environmental factors, the readings of the reflectance photodetector 6 and the interferometric photodetector 4 can be compared with the strongest interference database If there is matching data, then this position is the strongest constructive interference, so that the laser interferometer of this embodiment can achieve the ability to resist environmental interference.

As a preferred solution of this embodiment, the calibration method of this embodiment also includes step 4, generating the weakest interference database: moving the moving corner reflector 3 in an environment with clean air, and when shooting at the interferometric photoelectric detection When the interference beam of the device 4 is the weakest destructive interference, fix the moving angle reflector 3, record the readings of the reflection measurement photodetector 6 and the interferometric photodetector 4 readings at this time, and change the air environment to make the reflection measurement photoelectric detection The readings of the detector 6 are changed, and the readings of several reflection measurement photodetectors 6 and the corresponding readings of the interferometric photodetector 4 are recorded at the same time to obtain the weakest interference database.

As a further preferred solution, the calibration method of the present application also includes step five, generating a 1/n wavelength interference database, where n is a positive integer greater than or equal to 2: moving the movable corner reflector 3 in a clean air environment, When the interference beam directed at the interferometric photodetector 4 is the strongest constructive interference, continue to move the distance of 1/2n wavelength, and record the readings of the reflection measurement photodetector 6 and the interferometric photodetector 4 at this time. , and then change the air environment to change the readings of the reflection measurement photodetector 6, and simultaneously record the readings of several reflection measurement photodetectors 6 and the corresponding interferometric photodetector 4 readings to obtain a 1/n wavelength interference database.

When two laser beams interfere, the optical path difference between the adjacent strongest constructive interference and the weakest destructive interference is half a wavelength. In the calibration method of this application, for the strongest constructive interference, the weakest Both destructive interference and 1/n wavelength interference have been calibrated, that is to say, when the laser interferometer of the present application is used for actual measurement, the readings of the photodetector 6 for reflection measurement and the readings of photodetector 4 for interferometric measurement can be compared with the most Compare the data in the strong interference database, the weakest interference database, and the 1/n wavelength interference database, and determine whether the position is the strongest constructive interference, the weakest destructive interference or 1/n wavelength interference according to the matching of the data. This makes the laser interferometer of the present application not only resistant to environmental interference, but also improves measurement accuracy.

Embodiment 3, adopt the measuring method of above-mentioned laser interferometer and calibration method,

A kind of above-mentioned measuring method that adopts contrast type anti-interference corner reflector laser interferometer and above-mentioned calibration method:

In the actual measurement environment, suppose the signal reading measured by the reflection measurement photodetector 6 is x, the signal reading obtained by the interferometric photodetector 4 measurement is y, and the x value and the y value are stored in the strongest interference database , the weakest interference database, and the 1/n wavelength interference database for comparison. When the x value and y value match a certain set of values in the strongest interference database, this position is considered to be the strongest constructive interference position. When The x value and y value match a set of values in the weakest interference database, and this position is considered as the weakest destructive interference position. When the x value and y value match a set of values in the 1/n wavelength interference database match, it is considered that this position is the 1/n wavelength interference position.

In the measurement method of this embodiment, the interference situation of the current interference beam is determined through the x value and the y value, so as to realize the ability of resisting environmental interference and improve the measurement accuracy at the same time.

As a preferred solution of this embodiment, the matching threshold △ of the y value is set, and the value corresponding to the interferometric photodetector in the strongest interference database, the weakest interference database, and the 1/n wavelength interference database is set to y′, according to the x value Query y' for the strongest interference database, the weakest interference database, and the 1/n wavelength interference database. If there is y' such that |y-y'|<△, then distinguish the database where y' is located. If y' is in the most In the strong interference database, this position is considered as the strongest constructive interference position, if y' is in the weakest interference database, this position is considered as the weakest destructive interference position, if y' is in the 1/n wavelength interference database , then this position is considered to be the 1/n wavelength interference position.

As a further preferred solution, set the value corresponding to the reflectance measurement photodetector in the strongest interference database, the weakest interference database, and the 1/n wavelength interference database as x', and in actual measurement, select x that is closest to the actual measured value x 'As a matching value, query y' from the strongest interference database, the weakest interference database, and 1/n wavelength interference database according to the value of x', if there is y' such that |y-y'|<△, then distinguish y' If y' is in the strongest interference database, this position is considered as the strongest constructive interference position, if y' is in the weakest interference database, this position is considered as the weakest destructive interference position, if y 'In the 1/n wavelength interference database, this position is considered to be the 1/n wavelength interference position.

As a preferred solution of this embodiment, the size of the matching threshold Δ ensures that y' is a unique value when |y-y'|<Δ is satisfied during data query. When the matching threshold △ is large, a set of x values and y values may match two or more sets of x' and y' values, which brings inconvenience to the measurement, so the threshold △ should be matched first, so that during the measurement A set of x and y values matches at most a set of x' and y' values for easy measurement.

As a preferred solution of this embodiment, the size of the matching threshold △ is set according to the accuracy requirements of the actual measurement. When a high-precision measurement value is required, a smaller matching threshold is used. For faster measurements, a larger matching threshold is used.

As a further preferred solution, set Δ=5%.

In the measurement method of this embodiment, by setting the matching threshold △, the size of the matching threshold △ is set according to the requirements of the actual measurement accuracy, so as to facilitate the matching selection of data during the measurement process and reduce the difficulty of measurement.

The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the specification has described the present invention in detail with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned specific implementation methods, so Any modification or equivalent replacement of the present invention; and all technical solutions and improvements that do not deviate from the spirit and scope of the invention shall be covered by the claims of the present invention.

Claims (10)

1. A contrast type anti-jamming corner reflector laser interferometer includes a laser source, a fixed corner reflector, an interferometric photodetector, a moving corner reflector and a beam splitter group, and the laser beam emitted by the laser source passes through the After the beam splitter group is divided into a first laser beam and a second laser beam, the first laser beam shoots to the fixed-angle reflector, and then shoots to the beam-splitter group again after being reflected by the fixed-angle reflector. After passing through the spectroscopic mirror group, it is directed to the interferometric photodetector, and the second laser beam is directed to the moving angle reflector, and then directed to the spectroscopic mirror group again after being reflected by the moving angle reflecting mirror. After the spectroscopic mirror group shoots to the interferometric photodetector, the first laser beam and the second laser beam interfere when they shoot to the interferometric photodetector, and it is characterized in that it also includes a reflection measurement photodetector After the second laser beam is irradiated by the moving angle reflector to the beam splitter group, a reflected laser beam is also formed, and the reflected laser beam is irradiated to the reflection measurement photodetector. 2. contrast type anti-interference angle reflector laser interferometer as claimed in claim 1, is characterized in that, described spectroscope group comprises the first spectroscope and the second spectroscope, and the laser beam that described laser source emits first The first laser beam is emitted to the first beam splitter, reflected by the first beam splitter to form the first laser beam, transmitted through the first beam splitter to form the second laser beam, and the first laser beam shoots to the fixed angle reflector, and then shoots to the The first beam splitter is then transmitted through the first beam splitter, the second laser beam is directed to the moving angle reflector, and then directed to the second beam splitter after being reflected by the moving angle reflector , transmits through the second beam splitter and shoots to the first beam splitter, and interferes with the first laser beam transmitted from the first beam splitter, forms an interference beam and shoots to the interferometric photodetector The second laser beam irradiated to the second beam splitter by the moving corner reflector is also reflected by the second beam splitter to form the reflected laser beam. 3. a calibration method for the contrast type anti-interference angle mirror laser interferometer described in claim 1 or 2, is characterized in that, comprises the following steps: Step 1. Position adjustment: adjust the positions of the laser source, fixed angle reflector, beam splitter group, interferometric photodetector, reflection measurement photodetector and moving angle reflector; Step 2, adjust the optical path: start the laser source, and further accurately adjust the positions of the fixed angle reflector, the beam splitter group, the interferometric photodetector, the reflection measurement photodetector and the moving angle reflector, so that the optical path of the laser interferometer reaches Design requirements; Step 3, generate the strongest interference database: move the movable corner reflector in an environment with clean air, and fix the movable corner reflector when the interference beam directed at the interferometric photodetector is the strongest constructive interference , record the reflection measurement photodetector readings and the interferometric photodetector readings at this time, change the air environment to change the reflection measurement photodetector readings, and record several reflection measurement photodetector readings and corresponding interferometric photodetectors at the same time readings to obtain the strongest interference database. 4. The calibration method according to claim 3, further comprising step 4, generating the weakest interference database: moving the movable angle reflector in an air-clean environment, when directed to the interferometric photoelectric When the interference beam of the detector is the weakest destructive interference, fix the moving angle reflector, record the readings of the photodetector for reflection measurement and the photodetector for interferometric measurement at this time, and change the air environment to change the reading of the photodetector for reflection measurement , and simultaneously record the readings of several reflection measurement photodetectors and the corresponding interferometric photodetector readings to obtain the weakest interference database. 5. The calibration method according to claim 4, further comprising step 5, generating a 1/n wavelength interference database, where n is a positive integer greater than or equal to 2: moving the mobile device in a clean air environment Corner reflector, when the interference beam directed at the interferometric photodetector is the strongest constructive interference, continue to move the distance of 1/2n wavelength, and record the reflection measurement photodetector reading and the interferometric photodetector at this time reading, and then changing the air environment to change the readings of the reflection measurement photodetectors, and simultaneously record several reflection measurement photodetector readings and corresponding interferometric photodetector readings to obtain a 1/n wavelength interference database. 6. a kind of measuring method that adopts the contrast type anti-interference angle reflector laser interferometer described in claim 1 or 2 and the calibration method described in claim 5, it is characterized in that, in actual measurement environment, set described reflection The signal reading measured by the measuring photodetector is x, the signal reading obtained by the interferometric photodetector measurement is y, and the x value and y value are stored in the strongest interference database, the weakest interference database, and the 1/n wavelength interference database When the x value and y value match a certain set of values in the strongest interference database, this position is considered as the strongest constructive interference position; when the x value and y value match the weakest interference database If a set of values matches, this position is considered as the weakest destructive interference position. When the x value and y value match a set of values in the 1/n wavelength interference database, this position is considered as 1/n wavelength interference position. 7. measuring method as claimed in claim 6, is characterized in that, the matching threshold value of setting y value, set the numerical value corresponding to interferometric photodetector in the strongest interference database, the weakest interference database, 1/n wavelength interference database is y', according to the value of x, query y' on the strongest interference database, the weakest interference database, and the 1/n wavelength interference database. If y' exists, then distinguish the database where y' is located. If y' is in the strongest In the interference database, this position is considered to be the strongest constructive interference position, if y' is in the weakest interference database, then this position is considered to be the weakest destructive interference position, if y' is in the 1/n wavelength interference database, It is considered that this position is the 1/n wavelength interference position. 8. measuring method as claimed in claim 7, it is characterized in that, set the numerical value corresponding to reflection measurement photodetector in the strongest interference database, the weakest interference database, 1/n wavelength interference database to be x ', in actual measurement , select x' which is closest to the actual measured value x as the matching value, and query y' from the strongest interference database, the weakest interference database, and the 1/n wavelength interference database according to the x' value, and if there is y', then distinguish The database where y' is located, if y' is in the strongest interference database, this position is considered as the strongest constructive interference position, if y' is in the weakest interference database, this position is considered as the weakest destructive interference position, If y' is in the 1/n wavelength interference database, the position is considered to be the 1/n wavelength interference position. 9. The measurement method according to claim 7 or 8, wherein the size of the matching threshold guarantees that when data query is performed, y' is a unique value when satisfied. 10. The measurement method according to claim 9, characterized in that, the size of the matching threshold is set according to the accuracy requirements of actual measurement, when a high-precision measurement value is required, a smaller matching threshold is used, and when not Larger matching thresholds are used when high-precision measurements are required.