CN117871058A - A detection device and method for testing the parallelism of multiple optical axes - Google Patents

Abstract

The invention discloses a detection device and method for testing the parallelism of multiple optical axes. The detection device comprises an optical axis angle measurement module, a one-dimensional guide rail, a pentaprism, and a roll angle test module; wherein the roll angle test module consists of a roll angle test module part A and a roll angle test module part B, the roll angle test module part A is fixedly connected to the pentaprism through a mechanical structure, and the two move together along the one-dimensional guide rail; the roll angle test module part B is fixedly connected to the optical axis angle measurement module through a mechanical structure, and the two are fixed during the test; the optical axis of the optical axis angle measurement module is parallel to the optical axis of the roll angle test module; the optical axis of the optical axis angle measurement module is perpendicular to one of the right-angle surfaces of the pentaprism; and the optical axes of at least two branches of the multiple optical branches of the device to be tested are perpendicular to another right-angle surface of the pentaprism. The device can be used to perform multi-optical axis parallelism detection on optoelectronic instruments and military optical equipment, and the detection method itself has advantages such as good environmental adaptability.

Description

A detection device and method for testing the parallelism of multiple optical axes

Technical Field

The invention belongs to the technical field of optical equipment, and in particular relates to a detection device and method for testing the parallelism of multiple optical axes.

Background technique

Driven by various application requirements, optoelectronic instruments and equipment have become increasingly versatile in their development, such as multi-channel imaging, integration of imaging and laser strike, integration of laser emission and reception, integration of laser communication and remote sensing imaging, etc. This multi-functional integration in one optoelectronic instrument enables it to better meet various application requirements. Compared with multiple independent devices, it also has many advantages such as low cost, small size, low power consumption, high stability, and convenient use. The structure of this type of optoelectronic instrument is multi-optical path and multi-optical axis. Different optical branches are used to achieve different functions and together form complex optoelectronic instruments and equipment. For this type of complex optoelectronic instrument and equipment with multiple optical paths, in order to enable each optical branch to work together, such as aiming at the same observation/strike area, the pointing consistency between each optical branch needs to be within the allowable error range. The pointing direction of each optical branch is usually defined as its optical axis, and the parallelism of multiple optical axes is one of the key indicators of this type of complex optoelectronic instrument and equipment. For example, in high-orbit satellite laser communications, the parallelism between the laser receiving optical path and the laser transmitting optical path should be less than 1 arc second, otherwise the two optical paths cannot simultaneously point to the laser communication terminal on the other side, thus failing to achieve duplex mode laser communication, or even failing to achieve communication at all. Failure to meet this indicator means that the product has serious defects, so multi-optical axis parallelism testing of such optoelectronic instruments and equipment is an important part of its quality assurance.

At present, a variety of multi-axis parallelism detection methods for complex optoelectronic instruments and equipment have been developed. Among them, for the case where there is no lateral spacing (or the lateral spacing is very small) between the optical axes, such as a multi-axis system realized by beam combination and beam splitting with a dichroic mirror, the light beams of multiple optical branches basically overlap in space, and can be detected by autocollimator or parallel light tube methods. This type of detection equipment can receive the light beams of each branch at the same time, and detect the angles of each light beam by color separation or time division, thereby realizing the parallelism detection of multiple optical axes. Its technology is relatively mature and has been widely used in engineering.

However, for some optoelectronic instruments and equipment, there are various limiting factors that inevitably lead to lateral spacing between the various optical branches, and the distance between the various optical branches is relatively far. For example, in the artillery system, the system consists of a visible light aiming system, an infrared aiming system, a laser emission system, a laser receiving system and multiple muzzles, and typically uses multiple discrete optical systems, with a lateral spacing of several tens of centimeters between them. For such systems, the spacing between the optical branches is large, which exceeds the caliber coverage of detection equipment such as autocollimators or parallel light tubes, and a more advanced method is needed to complete the multi-optical axis parallelism detection of such systems.

For the detection of multi-axis parallelism with large spacing, the following methods are currently used: (1) Increasing the aperture of the collimator: This method can only cover a limited range of apertures, and the cost increases sharply with the increase in aperture. The detection equipment is bulky, and large-aperture collimators can generally only work when the optical axis is horizontal, which is not suitable for detecting the multi-axis parallelism of optoelectronic equipment in other pointing conditions. (2) Using electromechanical methods (such as a two-dimensional mobile platform) to move the autocollimator or parallel light tube in multiple optical branches: This method places extremely high precision requirements on its movement, is costly, takes a long time to test, and has poor environmental adaptability. Environmental instability factors during the test (such as temperature-induced structural deformation, environmental vibration, airflow changes, etc.) also have a significant impact on this method; (3) Testing the optical axis based on multiple theodolites and transferring the angle reference through mutual aiming between the theodolites: This method is limited by the accuracy of the theodolites themselves, and the significant impact of environmental instability factors during the test has not been overcome; (4) Using a pentaprism to achieve beam deflection or a double pentaprism to achieve lateral translation of the beam, the beam is deflected or translated to the same angle measuring device for angle testing: When the pentaprism deflects or translates the beam, its angle can only be maintained in one direction, and the other direction is affected by the roll rotation error of the pentaprism around the optical axis. Therefore, this method still has extremely high requirements for its mechanical accuracy and is therefore also more sensitive to the environment.

In summary, there is still a lack of high-precision solutions for multi-axis parallelism detection with large spacing. The problem of multi-axis parallelism detection of complex optoelectronic instruments and equipment is of great significance to the guarantee of their functions and performance, especially for some optoelectronic instruments and equipment and military optical equipment that need to have good environmental adaptability when used in the field. Multi-axis detection equipment and methods with the following characteristics are required: high precision; ability to detect optical axis parallelism in non-horizontal state; acceptable cost; short detection time; and good environmental adaptability of the detection method itself.

Summary of the invention

Aiming at the problem of multi-axis parallelism test between different optical branches in a multi-beam optical system, the present invention is based on the invention "Roll angle test device and test method based on interference measurement" with publication number CN116772750A, and combines the pentaprism beam deflection technology to propose a high-precision multi-axis parallelism detection device and method. The device can be used to perform multi-axis parallelism detection on optoelectronic instruments and military optical equipment. The spacing between its optical branches can reach up to several meters, and its accuracy can reach better than 1 arc second. It has moderate cost, short detection time, and the detection method itself has the advantages of good environmental adaptability. The detection device and method can translate the optical axis reference or plane reference laterally with high precision, and can be used in some other fields, such as realizing high-precision detection of planes, detecting the parallelism between mechanical reference planes with large spacing, etc.

The above purpose is achieved through the following technical solutions:

A detection device for testing the parallelism of multiple optical axes, comprising an optical axis angle measurement module, a one-dimensional guide rail, a pentaprism, and a roll angle test module; wherein the roll angle test module consists of a roll angle test module part A and a roll angle test module part B, the roll angle test module part A is fixedly connected to the pentaprism through a mechanical structure, and the two move together along the one-dimensional guide rail; the roll angle test module part B is fixedly connected to the optical axis angle measurement module through a mechanical structure, and the two are fixed during the test; the optical axis of the optical axis angle measurement module is parallel to the optical axis of the roll angle test module; the optical axis of the optical axis angle measurement module is perpendicular to one of the right-angle surfaces of the pentaprism; and the optical axes of at least two of the multiple optical branches of the device to be tested are perpendicular to another right-angle surface of the pentaprism.

Furthermore, the pentaprism adopts a hollow reflection form, including two reflection planes with a mutual angle equal to 22.5 degrees.

Furthermore, the optical axis angle measurement module is of reflective type, including an off-axis parabola and a folding plane reflector.

Furthermore, the optical axis angle measurement module includes a light source and a beam combiner, and the light emitted by the light source and the test light beam can emit a standard collimated light beam through the beam combiner.

Furthermore, a corner reflector is provided at the light outlet of the optical axis angle measurement module, and a working surface of the corner reflector faces the optical axis angle measurement module.

Furthermore, the roll angle test module A part includes a prism A; the roll angle test module B includes an interferometer and a prism B; after the parallel light beam emitted by the interferometer is refracted by the prism B, the emitted light beam is vertically incident on the inclined surface of the prism A, and after being reflected by the inclined surface of the prism A, the light beam returns to the interferometer along the original path for roll angle test.

The present invention also provides a detection method for testing the parallelism of multiple optical axes. The method is based on the above-mentioned detection device for testing the parallelism of multiple optical axes. The method comprises the following steps:

S1. Select two optical branches to be tested in the optical system to be tested, and adjust the relative spatial position relationship between the test device and the optical system to be tested so that the motion trajectory of the pentaprism along the one-dimensional guide rail can cover part of the aperture of the two optical branches to be tested;

S2. Move the pentaprism along the one-dimensional guide rail to the light beam range of one of the optical branches to be measured;

S3. When the pentaprism is aligned with the optical axis to be measured, the angle reading of the optical axis angle measurement module is recorded at the same time , and the readings from the roll angle test module part B/> ;

S4. Move the pentaprism along the one-dimensional guide to the light beam range of the other optical branch optical axis 2 to be measured;

S5. When the pentaprism is aligned with the optical axis 2, the angle reading of the optical axis angle measurement module is recorded at the same time , and the readings of the roll angle test module part B/> ;

S6. Based on the above test results, the angle deviation of the optical axis 2 of the optical branch to be tested relative to the optical axis 1 of the optical branch to be tested is calculated. is the optical axis parallelism error between the two optical branches, and the calculation formula is as follows:

,

In the above calculation formula, small angle approximation is used. In the typical 1 degree angle range, the relative error caused by approximation is better than one thousandth; in the 1 arc minute range, the relative error caused by approximation is better than one ten-thousandth.

Aiming at the problem of multi-axis parallelism test between different optical branches in a multi-beam optical system, the present invention is based on the applicant's previous research results, the invention "Roll angle test device and test method based on interferometry" with publication number CN116772750A, combined with the pentaprism beam deflection technology, and proposes a high-precision multi-axis parallelism detection device and method. The device can be used for multi-axis parallelism detection of optoelectronic instruments and military optical equipment. Its beneficial effects include the following aspects:

1. High detection accuracy. Both the roll angle test module and the optical axis angle measurement module can achieve 0.1 arc second accuracy. After compensation, the present invention can achieve sub-arc second accuracy. Its actual detection accuracy is often limited by the beam quality of the device under test and the system aberration.

2. The distance between the optical axes of each branch optical path is large, and its maximum distance is limited by the travel of the pentaprism scanning rail. Since the present invention has a low requirement on the precision of the pentaprism scanning rail and can achieve a long travel, the measurable optical axis distance can typically reach 3 meters;

3. Moderate cost. The present invention avoids the use of high-precision electromechanical motion. Compared with the method of relying on mechanical precision to improve detection accuracy, the present invention greatly reduces the cost;

4. The detection of the present invention can be completed automatically, and the detection time of a single test is short;

5. The present invention has good environmental adaptability. The angle changes caused by environmental unstable factors (such as structural deformation caused by temperature, environmental vibration, airflow changes, etc.) during the test process can be monitored in an appropriate manner and compensated in the test results. Therefore, the present invention can be applied to various field tests in harsh environments.

6. The present invention has good general application for various multi-optical axis optoelectronic instruments and military optical systems. Its detection application is not limited to visible light systems. By adopting a reflective pentaprism and a reflective optical axis angle measurement module, the detection equipment can test infrared, ultraviolet, and multi-band hybrid optical systems; the optical axis tested is not limited to the transmitting axis of the optical detection equipment, but can also test the receiving axis of its optical branch;

7. The present invention can be extended to some precision angle measurement application fields outside the optical field. For example, it can be used to detect the parallelism of multiple reference planes with lateral spacing based on the autocollimation mode, and applied to the detection in precision machining.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the structure of the present invention;

FIG2 is a schematic diagram of the working mode of the double pentaprism described in an embodiment of the present invention;

FIG3 is a multi-axis parallelism detection device including a reference beam described in an embodiment of the present invention;

FIG4 is a multi-optical axis parallelism detection device capable of testing receiving optical axes described in an embodiment of the present invention;

FIG5 is a coaxial calibration diagram of the transmitting and receiving test equipment described in an embodiment of the present invention;

FIG6 is a schematic diagram of the working state of the parallelism of the application and test reference plane described in an embodiment of the present invention;

Description of the components in the figure: 1. Optical axis angle measurement module; 102. Light source; 103. Beam combiner; 2. One-dimensional guide rail; 3. Pentaprism; 401. Part A of roll angle test module; 402. Part B of roll angle test module; 501. Optical axis one to be measured; 502. Optical axis two to be measured; 6. Compound prism; 7. Collimated light source; 8. Improved compound prism; 9. Reference plane to be measured; 10. Corner reflector.

Detailed ways

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Example 1

As shown in FIG1 , a detection device for testing the parallelism of multiple optical axes in this embodiment includes an optical axis angle measurement module 1, a one-dimensional guide rail 2, a pentaprism 3, and a roll angle test module; wherein the roll angle test module consists of a roll angle test module A part 401 and a roll angle test module B part 402, the roll angle test module A part 401 is fixedly connected to the pentaprism 3 through a mechanical structure, and the two move together along the one-dimensional guide rail 2; the roll angle test module B part 402 is fixedly connected to the optical axis angle measurement module 1 through a mechanical structure, and the two are fixed during the test; the optical axis of the optical axis angle measurement module 1 is parallel to the optical axis of the roll angle test module; the optical axis of the optical axis angle measurement module 1 is perpendicular to one of the right-angle surfaces of the pentaprism 3; and the optical axes of at least two branches (the first optical axis to be measured 501 and the second optical axis to be measured 502) of the multiple optical branches of the device to be tested are perpendicular to another right-angle surface of the pentaprism 3.

The roll angle test module, which is composed of the roll angle test module A part 401 and the roll angle test module B part 402, has a composition and method as detailed in the invention "Roll angle test device and test method based on interferometric measurement" (publication number CN116772750A) disclosed by the inventor. In the invention, the roll angle is obtained by multiplying the fringe angle difference between the two interference areas by a proportional factor related to the prism wedge angle. In addition, by using the two components of the average fringe inclination angle between the two interference regions, the other two angular degrees of freedom of the roll angle test module A part 401 relative to the roll angle test module B part 402 can be obtained. The subscripts x, y, and z are angle values, which respectively represent the rotation around the x-axis, the y-axis, and the z-axis in the coordinate system set in the present invention, and the same applies below. The above three angle readings/> The angular posture of the roll angle test module A part 401 relative to the roll angle test module B part 402 is fully described.

Using the above solution, a detection device for testing the parallelism of multiple optical axes in this embodiment, and a detection method for testing the parallelism of multiple optical axes include the following steps:

S1. Select two optical branches to be tested in the optical system to be tested, and adjust the relative spatial position relationship between the test device and the optical system to be tested so that the motion trajectory of the pentaprism along the one-dimensional guide rail can cover part of the aperture of the two optical branches to be tested;

S2. Move the pentaprism along the one-dimensional guide rail to the light beam range of one of the optical branches to be measured;

S3. When the pentaprism is aligned with the optical axis to be measured, the angle reading of the optical axis angle measurement module is recorded at the same time , and the readings from the roll angle test module part B/> ;

S4. Move the pentaprism along the one-dimensional guide to the light beam range of the other optical branch optical axis 2 to be measured;

S5. When the pentaprism is aligned with the optical axis 2, the angle reading of the optical axis angle measurement module is recorded at the same time , and the readings of the roll angle test module part B/> ;

S6. Based on the above test results, the angle deviation of the optical axis 2 of the optical branch to be tested relative to the optical axis 1 of the optical branch to be tested is calculated. is the optical axis parallelism error between the two optical branches, and the calculation formula is as follows:

In the above calculation formula, small angle approximation is used. In the typical 1 degree angle range, the relative error caused by approximation is better than one thousandth; in the 1 arc minute range, the relative error caused by approximation is better than one ten-thousandth.

Example 2

The difference between this embodiment and Embodiment 1 is that, for ultraviolet or infrared bands, or when the multiple branches of the optical system include more than one band, the optical axis angle measurement module 1 can be reflective, typically consisting of an off-axis parabola and necessary folding plane reflectors; the pentaprism can be hollow reflective, consisting of two reflecting planes with an angle equal to or approximately 22.5 degrees.

Example 3

As shown in FIG2 , the difference between this embodiment and embodiment 1 is that in this embodiment, two pentaprisms are used to test two optical branches, one of which is fixed in the optical path of the farther optical branch to bend the light beam of the optical path; for the closer optical branch, the composite prism 6 moves along the guide rail, the composite prism 6 is composed of a pentaprism and a 22.5-degree prism, and a partial reflection film is used on the common surface of the pentaprism and the 22.5-degree prism constituting the composite prism 6, the light beam folded by the pentaprism fixed in the optical path of the farther optical branch can pass through the composite prism 6, and the composite prism 6 is moved to the light outlet of the other optical branch to be tested, and the light beam can also be tested for the optical axis angle after being turned. Similarly, the composite prism 6 also has a corresponding roll angle test module A part 401 connected to it to realize the monitoring of its roll angle. In terms of the test method, the test result of the pentaprism fixed in the optical path of the farther optical branch is subtracted from the angle measurement result of the composite prism 6, and then the standard measurement calculation described above is performed. This extended mode can further improve the test method's ability to resist environmental interference, such as the impact of vibration on measurement, airflow changes, and the impact caused by changes in the force of related mechanical structures with temperature and working angle.

Example 4

As shown in FIG3 , the difference between this embodiment and embodiment 1 is that, in order to further improve the test stability, a collimated light source 7 is used to connect with the one-dimensional guide rail 2, and the direction of its optical axis is the same as or close to the direction of the one-dimensional guide rail 2. An improved composite prism 8 is used to replace the pentaprism. The composite prism is composed of a pentaprism and a 22.5-degree prism, and a partial reflective film is used on their common surface. The improved composite prism 8 can fold the light beam from the optical branch, and can also pass the reference light beam from the collimated light source 7. In terms of the test method, the angle measurement result of the beam folded by the improved composite prism 8 is Component, minus the corresponding component of the test result of the collimated light source, and then perform the standard measurement calculation described above.

Example 5

As shown in FIG4 , the difference between this embodiment and embodiment 1 is that the present invention can extend the receiving axis test function of the optical branch, expand the optical axis angle measurement module, add a light source 102 and a beam combiner 103, so that while testing the angle of the incident light beam, it can also emit a standard collimated light beam, which can be folded by a pentaprism and incident on the optical branch to be tested. After the standard collimated light beam is incident on the optical branch to be tested, if the optical branch to be tested contains a receiving part (such as a planar array detector, such as a four-quadrant detector), the spot position of the detector inside it can be used based on its focal length to obtain the angle between the visual axis corresponding to the center point of the detector and the collimated light beam, thereby realizing the angle detection of the receiving axis of the optical branch. By switching the working wavelength of the light source 102, the output of standard collimated light beams of multiple different wavelengths can be realized for testing different optical branches.

Example 6

As shown in FIG5 , the difference between this embodiment and embodiment 1 is that, for a multi-optical axis parallelism detection device with a receiving axis test function, in order to further improve the accuracy, a corner reflector 10 can be connected to the light outlet of the optical axis angle measurement module 1, and the working surface of the corner reflector 10 faces the optical axis angle measurement module 1. The corner reflector 10 can be removed from the optical path by electric means or manual means, and after the calibration is completed, it is removed, and then the standard multi-optical axis parallelism detection process is carried out.

Example 7

As shown in FIG6 , the difference between this embodiment and embodiment 1 is that this embodiment can be extended to test the relative angle between reference planes (or between various areas of a large reference plane), and is applied to processes such as mechanical manufacturing and instrument and equipment assembly. On the reference plane to be tested, an optical flat plate 901 with good parallelism on both sides is used, close to the reference plane 9 to be tested, and a pentaprism 3 is used to move along the one-dimensional guide rail 2 to its projection range, and each reference plane 9 to be tested is tested in turn, and the test is performed with reference to the standard multi-optical axis parallelism detection process. After the test result is divided by 2, it is the actual angle difference between the reference planes. Its detection accuracy is mainly limited by the plane accuracy of the reference plane to be tested itself. For reference planes with good plane accuracy and relatively smooth, the optical flat plate 901 can also be omitted, and the test can be directly implemented by using the self-reflection of the reference plane 9 to be tested.

Test example:

In order to test the optical axis parallelism of each branch of a 1m-diameter laser communication ground terminal, a detection device developed based on the method of the present invention has a typical implementation scheme as follows:

The optical axis angle measurement module 1 uses a collimator with a focal length of 1000mm and an aperture of 80mm as the main body, and a beam splitter prism with a side length of 30mm as the beam combiner 103. The receiving part for angle measurement uses ace 2 a2A4504-5gmBAS as a surface array detector with a resolution of 4096×4096 and a pixel size of 2.74um; the collimated light beam emitting part uses an FC/PC interface, and different optical fiber output light sources can be replaced as needed as the light source 102 of the module.

In order to perform coaxial calibration of the optical axis angle measurement module 1 with transmitting and receiving functions, a 50mm-diameter corner cone made of fused quartz is used as the corner reflector 10 with an accuracy of 10 arc seconds. A corner cone mounting seat is designed 50mm away from the light outlet of the light pipe, and the corner cone can be installed and removed manually.

The one-dimensional guide rail 2 is a domestically produced guide rail with a length of 2.2 meters and a servo motor for electric movement. The corresponding mechanical structure is designed and manufactured to connect the various parts of the testing equipment into a whole.

Pentaprism 3, made of fused quartz, with an effective aperture of 40 mm and a comprehensive angular accuracy of 5 arc seconds.

In the roll angle test module, the roll angle test module A part 401 uses a prism with a base angle of 0.8087 degrees, made of H-K9L, and a diameter of 100mm; the roll angle test module B part 402 uses a prism with a base angle of 1.500 degrees, made of H-K9L, and a diameter of 100mm, and uses a Zygo 4-inch interferometer to test the wavefront angle of each region, and uses a folding plane reflector to fold the interference detection optical path when necessary. For the implementation method of calculating roll, please refer to the invention patent "Roll angle test device and test method based on interferometric measurement" authorized by our company, with publication number CN116772750A.

The 1m aperture laser communication ground terminal was tested, which contains 6 transmitting antennas and one receiving antenna, each of which has multiple optical branches. During the system adjustment process, the above-mentioned equipment and method are used to test the parallelism of the optical axis of each transmitting antenna and the receiving antenna in turn, and the test results are used as a guide to adjust or calibrate the optical axis angle of each branch to within the accuracy of 1 arc second.

The equipment was used to test the angle between two plane reference surfaces with a span of 1.5m in another project. Two parallel plates were used. The material was fused quartz with a thickness of 10mm and an effective aperture of 80mm. The double-sided parallelism was better than 1 arc second and both sides were not coated.

Claims (7)

1. The detection equipment for testing the parallelism of multiple optical axes is characterized by comprising an optical axis angle measurement module, a one-dimensional guide rail, a pentaprism and a roll angle test module; the rolling angle testing module consists of a rolling angle testing module A part and a rolling angle testing module B part, wherein the rolling angle testing module A part is fixedly connected with the pentaprism through a mechanical structure and moves along a one-dimensional guide rail together; the rolling angle testing module B part is fixedly connected with the optical axis angle measuring module through a mechanical structure, and the rolling angle testing module B part and the optical axis angle measuring module are fixed in the testing process; the optical axis of the optical axis angle measurement module is parallel to the optical axis of the roll angle test module; the optical axis of the optical axis angle measuring module is vertical to one right angle surface of the pentaprism; at least two branch optical axes of a plurality of optical branches of the device to be tested are perpendicular to the other right-angle surface of the pentaprism.

2. A test device for testing the parallelism of multiple optical axes according to claim 1, characterized in that the pentaprism takes the form of a hollow reflection comprising two reflection planes with an included angle equal to 22.5 degrees.

3. The apparatus of claim 1, wherein the optical axis goniometer module comprises a reflective type including an off-axis parabolic surface and a turning plane mirror.

4. A testing device for testing parallelism of multiple optical axes according to claim 1, wherein the optical axis angle measuring module comprises a light source and a beam combiner, and the light emitted by the light source and the test beam can emit a standard collimated beam through the beam combiner.

5. A testing device for testing parallelism of multiple optical axes according to claim 1, characterized in that at the light outlet of the optical axis angle measurement module, there is provided a corner reflector with its working face facing the optical axis angle measurement module.

6. A detection apparatus for testing multi-axis parallelism according to one of claims 1-5, wherein the roll angle testing module a section comprises a prism a; the roll angle testing module B comprises an interferometer and a prism B; after the parallel light beam emitted by the interferometer is refracted by the prism B, the emitted light beam vertically enters the inclined plane of the prism A, and after being reflected by the inclined plane of the prism A, the light beam returns to the interferometer in an original path for rolling angle test.

7. A detection method for testing multi-axis parallelism, which is based on a detection apparatus for testing multi-axis parallelism as claimed in one of claims 1-6, characterized in that the method comprises the steps of:

s1, selecting two optical branches to be tested in an optical system to be tested, and adjusting the relative spatial position relation between the testing equipment and the optical system to be tested so that the movement track of the pentaprism along the one-dimensional guide rail can cover part of the calibers of the two optical branches to be tested;

s2, enabling the pentaprism to move along the one-dimensional guide rail to a light-emitting beam range of a first optical axis of one optical branch to be detected;

s3, under the condition that the pentaprism is aligned with the optical axis to be measured, simultaneously recording the angle reading of the optical axis angle measurement moduleAnd the reading of the roll angle test module part B +.>；

S4, enabling the pentaprism to move along the one-dimensional guide rail to be within a light-emitting beam range of a second optical axis of the optical branch to be detected;

s5, under the condition that the pentaprism is aligned with the optical axis II, simultaneously recording the angle reading of the optical axis angle measuring moduleAnd the reading of the roll angle test module part B +.>；

S6, calculating and obtaining the angle deviation of the optical axis of the optical branch to be tested relative to the first optical axis of the optical branch to be tested based on the test resultFor the optical axis parallelism error between two optical branches, the calculation formula is as follows:

，

in the calculation formula, small-angle approximation is adopted, and the relative error caused by the approximation is better than one thousandth in a typical angle range of 1 degree; in the 1-angle range, the relative error due to approximation is better than one ten thousandth.