A dual-beam parallelism precision detection device

Abstract

A precision dual-beam parallelism detection device is disclosed for detecting the parallelism of a first test beam and a second test beam arranged parallel to each other with a distance L between them. The device includes an autocollimation angle measurement unit comprising a focusing lens and a photoelectric position detector located on the same optical axis. The photosensitive surface of the photoelectric position detector is located at the focal plane of the focusing lens. The focusing lens and the photoelectric position detector are mounted on a multi-degree-of-freedom attitude adjustment mechanism. The beam steering unit is a cornerstone prism used to deflect either the first or second test beam by 180° before it enters the focusing lens. The cornerstone prism has a first mounting point and a second mounting point, the center of which is located on the optical axis of the focusing lens. This invention features a simple optical path, wide applicability, and utilizes differential measurement to eliminate zero-position errors, achieving high-precision dual-beam parallelism measurement.

Description

Technical Field

[0001] This application relates to the field of laser precision measurement technology, and more specifically to a dual-beam parallelism precision detection device, which is particularly suitable for the detection and calibration of dual-beam parallelism in a dual-beam five-degree-of-freedom geometric error laser measurement system. Background Technology

[0002] In high-end equipment such as CNC machine tools, coordinate measuring machines, and lithography machines, the six geometric errors of linear motion axes are key factors affecting accuracy. Among them, the detection of roll angle error typically requires the use of two parallel measurement laser beams. Currently, the mainstream method for generating dual beams is beam splitting using a beam-splitting prism. However, due to the influence of optical component manufacturing errors, assembly deviations, and ambient temperature, the parallelism of the two beams is difficult to maintain in the long term and will drift over time, directly leading to a decrease in the accuracy of roll angle measurement. Therefore, in-situ detection and calibration of the parallelism of the two beams is crucial.

[0003] The main methods for dual-beam parallelism detection and calibration in the prior art are as follows: 1. Using special optical lens groups such as cornerstone prisms and transmission gratings to generate double beams with better parallelism. Chinese patent CN217932296U discloses a device for generating parallel beam pairs by using cemented prisms for beam splitting and transmission gratings for diffraction. The parallelism of the generated double beams is limited by the processing errors and assembly errors of the optical elements themselves, which will lead to a slight directional difference between the two beams, and this difference is difficult to quantify and eliminate.

[0004] 2. Using other standard instruments, such as laser interferometers and levels, precision angle measuring instruments are employed, with the assistance of a linear motion axis, to measure and compare the propagation directions of the two beams. The measurement accuracy of this method is limited by the geometric error of the linear motion axis itself, and it requires additional precision motion equipment, resulting in a complex and costly system.

[0005] 3. Chinese patent CN113091652A integrates two sets of monitoring optical paths within the system to measure and compensate for the non-parallelism error between the two beams in real time. While this method avoids dependence on external linear motion references, it introduces additional optical monitoring units and complex signal processing circuits, increasing the complexity and cost of the system itself.

[0006] 4. Two beams of light are converged to the focal plane using a large-aperture lens, and the light spot is captured by an image sensor to calculate parallelism. However, the lens aperture must be larger than the beam spacing, which makes the system bulky and expensive. Image acquisition and processing increase the complexity of the system, and the accuracy is limited by the sensor resolution and lens aberrations. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art and solve the problems of the existing technology, such as the influence of inherent errors of the optical system, reliance on external motion reference, and the complexity and inconvenience of the measurement system, this application provides a precision detection device for dual-beam parallelism to detect the parallelism between two parallel beams.

[0008] This application provides a precision dual-beam parallelism detection device for detecting the parallelism of a first test beam and a second test beam arranged parallel to each other with a distance of L. The device comprises: The autocollimation angle measurement unit includes a focusing lens and a photoelectric position detector located on the same optical axis. The photosensitive surface of the photoelectric position detector is located at the focal plane of the focusing lens. The focusing lens and the photoelectric position detector are mounted on a multi-degree-of-freedom attitude adjustment mechanism. A beam steering unit, which is a cornerstone prism, is used to deflect either the first or second beam under test by 180° before directing it into the focusing lens. The cornerstone prism has a first mounting point and a second mounting point, the center of which is located on the optical axis of the focusing lens. The symmetrical mounting point design ensures that the two deflected beams are symmetrically incident about the optical axis, satisfying the symmetry condition for differential operations.

[0009] To ensure that the two redirected measurement beams are symmetrically incident on the autocollimating angle measuring unit, as an improvement to the aforementioned dual-beam parallelism precision detection device, the distance between the first and second mounting points is half the distance L between the two beams to be measured. This ensures that when the corner cube prism switches between the two points, its movement trajectory is perpendicular to the beam arrangement direction, and guarantees that the measurement light path formed by reflections from the two points is completely symmetrical with respect to the optical axis of the autocollimating angle measuring unit, thereby achieving zero-position error cancellation.

[0010] Furthermore, the distance between the central axis of the first mounting point and the optical axis of the focusing lens, and the distance between the central axis of the second mounting point and the optical axis of the focusing lens, are both L / 4.

[0011] To address the issue that the zero-position error (i.e., the deviation of its optical axis from the ideal reference) of the autocollimating angle measurement unit affects the single measurement result, thus preventing the accurate extraction of the minute angle between the two beams, an improvement to the aforementioned dual-beam parallelism precision detection device is proposed. When the cornerstone prism is located at the first mounting point, the first beam to be measured is deflected 180° by the cornerstone prism to form a first measuring beam. The first measuring beam is then directed by the focusing lens to the photoelectric position detector to obtain the propagation direction of the first measuring beam. When the cornerstone prism is located at the second mounting point, the second beam to be measured is deflected 180° by the cornerstone prism to form a second measuring beam. The second measuring beam is then directed by the focusing lens to the photoelectric position detector to obtain the propagation direction of the second measuring beam.

[0012] The parallelism between the first and second beams under test is obtained by performing a differential calculation on the results of two measurements obtained by the photoelectric position detector. By sequentially measuring the directions of the two beams under test using the same set of angle measuring units and subtracting the two readings, the inherent zero-position error of the autocollimating angle measuring unit is canceled out as a common term during the calculation process. The final result directly reflects the angle between the two beams, thus realizing the differential cancellation of the zero-position error of the device in principle and improving the measurement accuracy.

[0013] To address the challenge of transforming the aforementioned difference principle into precise and executable mathematical operations to quantitatively obtain parallelism values, this solution provides a specific mathematical model and calculation formula. An O-XYZ coordinate system is established for the propagation direction of the two beams under test, with the X-axis along the propagation direction of the beams under test, the Y-axis perpendicular to the X-axis and along the horizontal direction, and the Z-axis along the vertical direction. The angle between the vertical optical axis and the autocollimation angle measurement unit is calculated using equation ①. : ① Equation ② represents the first reading of the autocollimation angle measurement unit. : ② Equation ③ represents the second reading of the autocollimation angle measurement unit. : ③ The parallelism between the first and second test beams is calculated using equation ④. : ④ in: This represents the displacement of the light spot along the Z-axis on the photoelectric position detector. f is the focal length of the focusing lens; The initial angle between the first light to be measured and the optical axis of the autocollimating angle measuring unit; The parallelism includes vertical parallelism and horizontal parallelism. Vertical parallelism is calculated by formulas ①-④, and horizontal parallelism is calculated by the corresponding Y-axis formula. The derivation method is the same as that for the Z-axis direction.

[0014] Furthermore, the self-collimating angle measurement unit also includes a magnetic base, and the multi-degree-of-freedom attitude adjustment mechanism is mounted on the magnetic base.

[0015] To address the issues of positioning and fixation, and finely adjusting the initial attitude to minimize the zero-position error before the first measurement, this improved dual-beam parallelism precision detection device also includes a mounting base. The multi-degree-of-freedom attitude adjustment mechanism is attached to the mounting base via a magnetic base. By adjusting the spatial attitude of the multi-degree-of-freedom attitude adjustment mechanism, the optical axis of the first beam under test is made parallel to the optical axis of the focusing lens, thereby reducing the zero-position error of the autocollimation angle measurement unit. The principle of differential zero-position error cancellation is as follows: the zero-position error δ in the two measurements is canceled out as a common term, and the differential result θ1-θ2=2θ directly reflects the angle between the two beams. This scheme simplifies the initial alignment operation and reduces the residual error in subsequent differential calculations.

[0016] To avoid additional measurement errors caused by placement deviations when switching between two mounting points of the corner cube prism, and to ensure its positional repeatability, as an improvement to the aforementioned dual-beam parallelism precision testing device, the mounting base is provided with a first positioning part and a second positioning part corresponding to the first and second mounting points. The corner cube prism can be switched between the first and second positioning parts. This facilitates the consistency of the corner cube prism's position each time, improving the reliability and repeatability of the measurement process.

[0017] To address the inefficiency and error-prone nature of manual data recording and calculation, this device, as an improvement to the aforementioned dual-beam parallelism precision detection device, further includes a data processing unit. This data processing unit is electrically connected to the photoelectric position detector and is used to receive and process the output signal of the photoelectric position detector to obtain the parallelism between the first and second beams under test. This achieves automatic acquisition, storage, calculation, and result output of photoelectric signals, improving detection efficiency and the reliability of the results.

[0018] The technical advantages of this application are as follows: 1. This application utilizes an autocollimating angle measurement unit composed of a focusing lens and a photoelectric position detector, combined with the 180° beam steering characteristic of a corner bevel prism, to directly measure the parallelism of two beams through a single optical sensing system and a switchable optical reflection element. This scheme features a simple optical path, eliminating the need for external auxiliary equipment such as linear motion axes, effectively reducing error sources. Furthermore, by fixing the autocollimating angle measurement unit and only switching the corner bevel prism position to sequentially measure the two beams, and performing differential processing on the two readings, the zero-position error and time-dependent drift of the autocollimating angle measurement unit itself can be offset. This ensures that the final measurement result primarily reflects the parallelism deviation between the two beams, achieving differential elimination of the zero-position error and improving measurement accuracy and long-term stability.

[0019] 2. This invention, by setting a specific geometric relationship between the two mounting points of the cornerstone prism, enables the device to adapt to dual-beam measurement requirements with different spacings. Only the positions of the mounting points need to be adjusted, making it highly versatile. The entire device has a compact structure, and optical components can be selected as needed, allowing for direct signal processing. The use of a magnetic base for fixation makes the installation, positioning, and disassembly of the device more convenient, improving detection efficiency.

[0020] 3. Based on the above differential measurement principle, the measurement results cancel out the influence of the sensor's zero-position error. At the same time, the device has a simple structure and can be integrated with the data processing unit to realize the automatic acquisition of the spot position signal and the calculation of parallelism. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the optical path of the corner cube prism at the first mounting point in this application; Figure 2 This is a schematic diagram of the optical path of the corner cube prism at the second mounting point in this application; Figure 3 This is a schematic diagram of the angle measurement principle of the autocollimation angle measurement unit in this application; Figure 4 This is a schematic diagram showing the connection of the data processing unit in this application.

[0022] Explanation of reference numerals in the attached figures: 11. First beam to be measured; 111. First measuring beam; 12. Second beam to be measured; 121. Second measuring beam; 2. Autocollimating angle measuring unit; 21. Focusing lens; 22. Photoelectric position detector; 23. Multi-degree-of-freedom attitude adjustment mechanism; 24. Magnetic base; 31. Cornerstone prism; 311. First mounting point; 312. Second mounting point; 4. Mounting base; 41. First positioning part; 42. Second positioning part; 5. Data processing unit. Detailed Implementation

[0023] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] See Figure 1 and Figure 2 This embodiment provides a precision detection device for dual-beam parallelism, used to detect the parallelism of two beams to be tested, including an autocollimation angle measurement unit 2 and a beam steering unit 3.

[0026] The dual beams under test include a first beam 11 and a second beam 12, which are theoretically parallel and have a center-to-center distance of L. The dual beams under test can originate from the output of a dual-beam multi-degree-of-freedom geometric error laser measurement system or other dual-beam sources that require parallelism detection.

[0027] The self-collimating angle measurement unit 2 is fixedly installed on the propagation path of the two beams to be measured, that is, upstream of the beam propagation direction, and is used to detect the angle change of the beam after turning. It includes a focusing lens 21, a photoelectric position detector 22, a multi-degree-of-freedom attitude adjustment mechanism 23, and a magnetic base 24.

[0028] The focusing lens 21 can be an achromatic lens with a focal length of f and an optical axis that is approximately parallel to the main propagation direction of the two beams to be measured.

[0029] The photoelectric position detector 22 is a four-quadrant photoelectric detector or a high-resolution CCD. Its photosensitive surface is located at the focal plane of the focusing lens 21, that is, the distance between the photosensitive surface and the lens is equal to the focal length f, and it is used to detect the position coordinates of the light spot.

[0030] The central axes of the focusing lens 21 and the photoelectric position detector 22 coincide, and the photosensitive surface of the photoelectric position detector 22 coincides with the focal plane of the focusing lens 21.

[0031] The multi-degree-of-freedom attitude adjustment mechanism 23 can adopt a six-dimensional fine-tuning frame (including X / Y / Z translation and angle adjustment around the X / Y / Z axis) to precisely adjust the attitude of the focusing lens 21 and the photoelectric position detector 22 so that their optical axes coincide with the main optical axis of the dual beams to be measured.

[0032] The magnetic base 24 is fixed below the multi-degree-of-freedom attitude adjustment mechanism 23 and is magnetically attached to the reference surface of the mounting base 4 to achieve positioning and fixation.

[0033] The beam steering unit is a corner bevel prism 31, which can be a hollow corner bevel prism made of K9 glass with an aluminum-coated reflective surface. Its function is to redirect the incident beam 180° along its original direction, that is, the outgoing beam is parallel to the incident beam but in the opposite direction. The corner bevel prism 31 can be fixed to the propagation path of the two beams to be measured by a clamping mechanism.

[0034] The corner cube prism 31 has a first mounting point 311 and a second mounting point 312. The midpoint of the line connecting the two points is located on the central axis of the focusing lens 21 and the photoelectric position detector 22, meaning the two points are symmetrical about the optical axis of the lens, and the distance between the two points is 1 / 2 of the distance L between the two beams to be measured, i.e., L / 2. The distance between the central axis of the first mounting point 311 and the center of the optical axis of the focusing lens 21 is set to L / 4; the distance between the central axis of the second mounting point 312 and the center of the optical axis of the focusing lens 21 is also L / 4.

[0035] When the corner bevel prism 31 is located at any installation point, the center of its reflecting surface is on the same horizontal plane as the optical axis of the autocollimating angle measuring unit 2, and the incident angles of the first beam to be measured 11 and the second beam to be measured 12 are symmetrical about the optical axis.

[0036] In this embodiment, an air bearing linear guide can be used to drive the corner cube prism 31 to move along the Y-axis, with the moving direction perpendicular to the direction of the beam arrangement (X-axis). The displacement platform is equipped with a grating ruler closed-loop control, and the point switching repeatability accuracy is ≤±0.1μm, reducing the deflection or jitter of the corner cube prism when switching between the first mounting point 311 and the second mounting point 312.

[0037] like Figure 1 As shown, when measuring the propagation direction of the first test light 111, the corner cube prism 31 is installed at the first installation point 311. After the first test light 111 is incident on the corner cube prism 31, it is refracted by the corner cube prism 31 at 180° to form the first measurement light 111. The measurement light 111 is incident on the focusing lens 21 and focused onto the photosensitive surface of the photoelectric position detector 22. By reading the output value of the photoelectric position detector 22, the propagation direction of the first test light 111 can be obtained.

[0038] like Figure 2As shown, when measuring the propagation direction of the second test light 121, the corner cube prism 31 is installed at the second installation point 312. After the second test light 121 is incident on the corner cube prism 31, it is refracted by the corner cube prism 31 at 180° to form the second measurement light 121. The measurement light 121 is incident on the focusing lens 21 and focused onto the photosensitive surface of the photoelectric position detector 22. By reading the output value of the photoelectric position detector 22, the propagation direction of the second test light 121 can be obtained.

[0039] By performing a differential calculation on the two measurement results, the parallelism value of the two beams under test without the zero-position error of the autocollimation angle measurement unit 2 can be obtained.

[0040] Zero-position error cancellation mechanism: The inherent zero-position error of the autocollimation angle measurement unit 2 (such as optical axis tilt δ) manifests as the same additional angle in both measurements: First measurement reading: θ1 = θ + δ Second measurement reading: θ2 = -θ + δ In the difference operation θ1-θ2=2θ, δ is canceled out as a common term, and the result reflects the angle 2θ between the two beams.

[0041] In this embodiment, an O-XYZ coordinate system is established for the propagation direction of the two beams to be measured, with the X-axis along the propagation direction of the beams to be measured, the Y-axis perpendicular to the X-axis and along the horizontal direction, and the Z-axis along the vertical direction. The angle between the vertical optical axis and the autocollimation angle measuring unit 2 is calculated using equation ①. : ① Equation ② represents the first reading of the autocollimation angle measurement unit 2. : ② Equation ③ represents the second reading of the autocollimation angle measurement unit 2. : ③ The parallelism between the first test beam 11 and the second test beam 12 is calculated using equation ④. : ④ in: This represents the displacement value of the light spot along the Z-axis on the photoelectric position detector 22; f is the focal length of focusing lens 21; The initial angle between the first light to be measured and the optical axis of the autocollimating angle measuring unit 2 is given.

[0042] The parallelism includes vertical parallelism and horizontal parallelism. Vertical parallelism is calculated by formulas ①-④, and horizontal parallelism is calculated by the corresponding Y-axis formula. The derivation method is the same as that for the Z-axis direction.

[0043] The device also includes a mounting base 4. In this embodiment, a high-stability granite base is used, with a finely ground surface. A standardized mounting plane is integrated on the base for fixing the multi-degree-of-freedom attitude adjustment mechanism 23. A magnetic base 24 is fixed to the bottom of the multi-degree-of-freedom attitude adjustment mechanism 23, which is magnetically attached to the mounting base 4.

[0044] Two sets of precision positioning holes are machined on the mounting base 4. The first positioning part 41 corresponds to the first mounting point 311, and a hardened steel sleeve is nested inside the hole. The second positioning part 42 corresponds to the second mounting point 312, and its structure is symmetrical with 41. The center distance between the two holes is L / 2. In one embodiment, the outer shell of the corner cube prism 31 can adopt a conical positioning design. When the first positioning part 41 is inserted, the conical surface is automatically centered. When switching to the second positioning part 42, only the corner cube prism 31 needs to be moved horizontally (the moving direction is perpendicular to the beam arrangement) and guided by a linear guide rail. After the corner cube prism 31 is inserted, it is locked by a pneumatic chuck or a manual knob to maintain the stability of the reflective surface position.

[0045] The device also includes a data processing unit 5, which is electrically connected to the photoelectric position detector 22. The data processing unit 5 collects the analog signal output by the photoelectric position detector 22 and uses a differential algorithm to calculate the parallelism between the first beam to be tested 11 and the second beam to be tested 12.

[0046] The detection method of this device includes the following steps: S1: The autocollimating angle measuring unit 2 is fixedly set on the incident side of the dual beams to be measured, and the attitude of the autocollimating angle measuring unit 2 is adjusted by the multi-degree-of-freedom attitude adjustment mechanism 23 so that the optical axis of the focusing lens 21 is parallel to the direction of the first beam 11 to be measured. S2: Place the cornerstone prism 31 at the first mounting point 311, so that the first beam to be measured 11 is turned 80° by the cornerstone prism 311 to form a first measuring light 111 that is parallel to the first beam to be measured 11. The first measuring light 111 is incident on the photoelectric position detector 22 through the focusing lens 21. Read the output signal of the photoelectric position detector 22 to obtain the first measurement result. S3: Keeping the attitude of the autocollimating angle measuring unit 2 unchanged, move the cornerstone prism 31 to the second mounting point 312, so that the second beam to be measured 12 is turned 180° through the cornerstone prism 31 to form a second measuring light 121 that is parallel to the second beam to be measured 12. The second measuring light 121 is incident on the photoelectric position detector 22 through the focusing lens 21. Read the output signal of the photoelectric position detector 22 to obtain the second measurement result. S4: Perform a difference operation based on the first measurement result and the second measurement result, wherein the difference operation subtracts the first measurement result from the second measurement result to eliminate the zero position error of the autocollimation angle measurement unit 2, and obtains the parallelism between the first beam to be measured 11 and the second beam to be measured 12.

[0047] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A precision dual-beam parallelism detection device, used to detect the parallelism of a first test beam (11) and a second test beam (12) arranged parallel to each other and spaced apart by a distance L, characterized in that, The device includes: The autocollimation angle measurement unit (2) includes a focusing lens (21) and a photoelectric position detector (22) located on the same optical axis. The photosensitive surface of the photoelectric position detector (22) is located at the focal plane of the focusing lens (21). The focusing lens (21) and the photoelectric position detector (22) are mounted on a multi-degree-of-freedom attitude adjustment mechanism (23). A beam steering unit, which is a corner cube prism (31), is used to turn the first beam to be tested (11) or the second beam to be tested (12) by 180° and then shoot it into the focusing lens (21); the corner cube prism (31) has a first mounting point (311) and a second mounting point (312), and the center of the line connecting the first mounting point (311) and the second mounting point (312) is located on the optical axis of the focusing lens (21).

2. The dual-beam parallelism precision detection device according to claim 1, characterized in that, The distance between the first mounting point (311) and the second mounting point (312) is 1 / 2 of the distance L of the dual beams (1) to be tested.

3. The dual-beam parallelism precision detection device according to claim 1, characterized in that, The distance between the central axis of the first mounting point (311) and the optical axis of the focusing lens (21) and the distance between the central axis of the second mounting point (312) and the optical axis of the focusing lens (21) are both L / 4.

4. The dual-beam parallelism precision detection device according to claim 1, characterized in that, When the corner prism (31) is located at the first mounting point (311), the first beam to be measured (11) is turned 180° by the corner prism (31) to form the first measuring light (111); the first measuring light (111) is directed to the photoelectric position detector (22) by the focusing lens (21) to obtain the propagation direction of the first measuring light (111); When the corner prism (31) is located at the second mounting point (312), the second beam to be measured (12) is turned 180° by the corner prism (31) to form a second measuring beam (121); the second measuring beam (121) is directed to the photoelectric position detector (22) by the focusing lens (21) to obtain the propagation direction of the second measuring beam (121); The results obtained from the two measurements by the photoelectric position detector (22) are differentially calculated to obtain the parallelism between the first beam to be measured (11) and the second beam to be measured (12).

5. The dual-beam parallelism precision detection device according to claim 4, characterized in that, An O-XYZ coordinate system is established for the propagation direction of the dual beams to be measured, with the X-axis along the propagation direction of the beams to be measured, the Y-axis perpendicular to the X-axis and along the horizontal direction, and the Z-axis along the vertical direction. The angle between the vertical optical axis and the autocollimation angle measurement unit (2) is calculated using equation ①. : ① Equation ② represents the first reading of the autocollimation angle measurement unit (2). : ② Equation ③ represents the second reading of the autocollimation angle measurement unit (2). : ③ The parallelism between the first test beam (11) and the second test beam (12) is calculated using equation ④. : ④ in: The displacement value of the light spot along the Z-axis on the photoelectric position detector (22); f is the focal length of the focusing lens (21); The initial angle between the first light to be measured and the optical axis of the autocollimating angle measuring unit (2); The parallelism includes vertical parallelism and horizontal parallelism. Vertical parallelism is calculated by formulas ①-④, and horizontal parallelism is calculated by the corresponding Y-axis formula. The derivation method is the same as that for the Z-axis direction.

6. The dual-beam parallelism precision detection device according to claim 1, characterized in that, The autocollimation angle measurement unit (2) also includes a magnetic base (24), and the multi-degree-of-freedom attitude adjustment mechanism (23) is mounted on the magnetic base (24).

7. The dual-beam parallelism precision detection device according to claim 6, characterized in that, It also includes a mounting base (4), and the multi-degree-of-freedom attitude adjustment mechanism (23) is attached to the mounting base (4) by the magnetic base (24). By adjusting the spatial attitude of the multi-degree-of-freedom attitude adjustment mechanism (23), the optical axis of the first beam to be measured (11) is parallel to the optical axis of the focusing lens (21) to reduce the zero position error of the autocollimation angle measuring unit (2).

8. The dual-beam parallelism precision detection device according to claim 7, characterized in that, The mounting base (4) is provided with a first positioning part (41) and a second positioning part (42) corresponding to the first mounting point (311) and the second mounting point (312), and the corner cube prism (31) can be switched between the first positioning part (41) and the second positioning part (42).

9. The dual-beam parallelism precision detection device according to claim 1, characterized in that, It also includes a data processing unit (5), which is electrically connected to the photoelectric position detector (22) and is used to receive and process the output signal of the photoelectric position detector (22) to obtain the parallelism between the first beam to be tested (11) and the second beam to be tested (12).

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