Angle measurement and calibration device of optical axis and method thereof

Abstract

The present invention provides an optical axis angle measurement calibration device and method thereof, belonging to the field of optical detection technology. The optical axis angle measurement calibration method measures an aspheric standard lens using a first differential confocal measurement system and a second differential confocal measurement system in sequence, obtains the inclination angle information and position information of the upper surface and the lower surface, constructs a function model based on the information and solves it, adjusts the position and angle of the optical axis based on the solution result, and realizes the angle measurement calibration of the optical axis. The technical solution of the present invention accurately solves the spatial vector of the optical axis and the spatial coordinates of the focus of the differential confocal measurement system, effectively and accurately adjusts the position and inclination angle of the optical axis based on the solution result, and uses the established function model and data analysis method to perform accurate measurement, truly reflects the actual situation of the surface of the object being measured, thereby reducing the randomness and error of the measurement result.

Description

Technical Field

[0001] The invention belongs to the technical field of optical detection, and in particular relates to an optical axis angle measurement and calibration device and a method thereof. Background Art

[0002] The parallelism of the upper and lower surfaces of a large-target back-illuminated CMOS detector is of great significance. This parameter directly affects the performance and application effect of the detector. It is an important factor affecting the imaging quality, measurement accuracy, sensitivity and system integration of the detector. Ensuring the parallelism of the upper and lower surfaces is not only related to the consistency and accuracy of the image, but also has a profound impact on the performance, stability and application effect of the detector. Therefore, in the design, manufacturing and calibration process of the detector, it is crucial to pay attention to the control and optimization of parallelism.

[0003] In parallelism measurement, optical axis calibration of optical probes not only helps to improve measurement accuracy and avoid measurement deviations caused by non-parallel optical axes, but also eliminates potential errors caused by structural asymmetry or improper probe position. Especially in high-precision measurement applications, optical axis calibration is particularly important, because even a small angle of inclination or deviation can significantly affect the accuracy of the measurement results, and thus affect subsequent data analysis and processing.

[0004] Before parallelism measurement, it is crucial to ensure that the optical axes of the optical probes on both surfaces are calibrated. The core purpose of optical axis calibration is to ensure that the points on the upper and lower surfaces of the object to be measured correspond to each other, that is, there is no angular offset between the optical axes of the two optical probes. This is crucial for the accuracy and consistency of the measurement. By ensuring that the optical probe's light beam accurately illuminates the corresponding positions on the upper and lower surfaces, the actual situation of the surface of the object to be measured can be truly reflected, thereby reducing the randomness and error of the measurement results.

[0005] At present, the commonly used optical axis calibration methods mostly use theodolite calibration, machine vision calibration or the fusion method of visible light and infrared images for calibration. However, due to the assembly error of the calibration equipment, the optical axis of the calibration equipment may not be parallel, resulting in additional errors when using the calibration equipment for calibration. The machine vision calibration method is not applicable in actual use, especially when it involves high-precision measurements, due to the errors introduced by machine vision during image recognition. Therefore, it is necessary to propose a new optical axis angle measurement calibration method for parallelism measurement to improve the accuracy of the optical axis angle measurement calibration of the optical probe. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and to provide an optical axis angle measurement and calibration device and method thereof.

[0007] To achieve the above object, the present invention adopts the following specific technical solutions:

[0008] A method for measuring and calibrating the angle of an optical axis, which implements the measurement and calibration of the angle of the optical axis through a double differential confocal measurement system;

[0009] The optical axis angle measurement calibration method comprises the following steps:

[0010] S1, placing an aspheric standard lens between the first differential confocal measurement system and the second differential confocal measurement system;

[0011] S2, using the first differential confocal measurement system and the second differential confocal measurement system to measure the aspheric standard lens in sequence, wherein the measurement range includes: the upper surface and the lower surface of the aspheric standard lens, respectively obtaining the inclination angle information and the position information of the upper surface and the lower surface, and constructing and solving the function model according to the information;

[0012] S3. According to the solution result, adjust the angle and position of the optical axis of the first differential confocal measurement system and the optical axis of the second differential confocal measurement system to achieve angle measurement calibration of the optical axis.

[0013] Furthermore, the measurement in step S2 is specifically:

[0014] The upper surface and the lower surface of the aspherical standard lens are measured using a first measuring beam and a second measuring beam with different wavelengths in sequence.

[0015] Furthermore, the measurement in step S2 is specifically:

[0016] S201, using the first differential confocal measurement system to measure the aspheric standard lens using the first measurement beam and the second measurement beam;

[0017] S202, respectively collecting the spot image signal, the pre-focus light intensity signal and the post-focus light intensity signal corresponding to the upper surface and the lower surface measured by the first measuring beam and the second measuring beam on the tilt angle receiving device, and obtaining the tilt angle information and the position information of the upper surface and the lower surface according to the collected signals;

[0018] S203, constructing a function model, wherein the function model at least includes: aspheric surface information of the aspheric standard lens, the tilt angle information, the position information, optical parameter information of the first differential confocal measurement system, the first absolute space coordinates of the upper surface focus, and the absolute space vector of the optical axis of the first differential confocal measurement system;

[0019] S204, solving the function model to obtain the first absolute space coordinates of the upper surface focus and the absolute space vector of the optical axis of the first differential confocal measurement system;

[0020] S205. Using the second differential confocal measurement system, measure the aspheric standard lens using the first measurement beam and the second measurement beam, repeat steps S202-S204, and obtain the second absolute spatial coordinates of the upper surface focus and the absolute spatial vector of the optical axis of the second differential confocal measurement system.

[0021] Furthermore, the constructed function model is specifically as follows:

[0022] First equation: The aspheric equation of the upper surface focus of the aspheric standard lens f top (x,y,z)=0;

[0023] Second equation: The aspheric equation of the lower surface focus measured by the first measuring beam: ;

[0024] Third equation: The aspheric equation of the lower surface focus measured by the second measuring beam: ;

[0025] Fourth equation: The angle equation between the upper surface normal vector and the optical axis of the first differential confocal measurement system:

[0026] . (i,o,p) =0;

[0027] Fifth equation: equation for the angle between the focus normal vector of the lower surface measured by the first measuring beam and the optical axis of the first differential confocal measurement system:

[0028] =0;

[0029] in, ;

[0030] Sixth equation: equation for the angle between the focus normal vector of the lower surface measured by the second measuring beam and the optical axis of the first differential confocal measurement system:

[0031] . =0;

[0032] in, ;

[0033] Wherein, top represents the upper surface; bot represents the lower surface; (x, y, z) represents the first absolute spatial coordinates of the focus of the upper surface; ( ) represents the absolute spatial coordinates of the lower surface measured by the first measuring beam; ( ) represents the absolute spatial coordinates of the lower surface measured by the second measuring beam; λ1 represents the first measuring beam; λ2 represents the second measuring beam; (i, o, p) represents the absolute spatial vector of the optical axis of the first differential confocal measurement system on the upper surface; The absolute space vector of the optical axis of the first differential confocal measurement system on the upper surface is ; an absolute space vector representing the refraction of the optical axis of the first differential confocal measurement system on the lower surface during measurement by the first measurement beam; an absolute space vector representing the refraction of the optical axis of the first differential confocal measurement system on the lower surface when the second measurement beam is measuring; A normal vector representing the focus of the upper surface; a focus normal vector representing the lower surface measured by the first measuring beam; a focus normal vector representing the lower surface measured by the second measurement beam; represents the rotation angle of the normal vector of the tangent plane where the focus of the upper surface measured by the first measuring beam or the second measuring beam is located within the tangent plane; represents the angle between the normal vector of the tangent plane at the focal point of the upper surface measured by the first measuring beam or the second measuring beam and the optical axis of the lower surface; represents the rotation angle of the normal vector of the tangent plane where the focus of the lower surface measured by the first measuring beam is located within the tangent plane; represents the angle between the normal vector of the tangent plane at the focus of the lower surface measured by the first measuring light beam and the optical axis of the lower surface; represents the rotation angle of the normal vector of the tangent plane where the focus of the lower surface measured by the second measuring beam is located within the tangent plane; represents the angle between the normal vector of the tangent plane at the focus of the lower surface measured by the second measuring beam and the optical axis of the lower surface; Indicates rotating the absolute space vector (i,o,p) around the Y axis The rotation matrix of ; Indicates rotating the absolute space vector (i,o,p) around the Z axis The rotation matrix of ; Indicates rotating the absolute space vector (i,o,p) around the Y axis The rotation matrix of ; Indicates rotating the absolute space vector (i,o,p) around the Z axis The rotation matrix of ; Indicates that the absolute space vector (i,o,p) is rotated around the Z axis first , and then rotate around the Y axis The rotation matrix of Indicates that the absolute space vector (i,o,p) is rotated around the Z axis first , and then rotate around the Y axis The rotation matrix of .

[0034] Furthermore, the method for obtaining the inclination angle information and the position information of the upper surface and the lower surface in step S202 is specifically as follows:

[0035] A method for obtaining tilt angle information: a peak position of the spot image signal and the tilt angle are matched one by one, the spot image signals of the upper and lower surfaces of the aspheric standard lens on the tilt angle receiving device are analyzed, and the tilt angle information of the upper and lower surfaces of the aspheric standard lens is obtained;

[0036] Method for obtaining position information: using the collected pre-focus light intensity signal and the post-focus light intensity signal to obtain a differential confocal signal curve, and according to the coordinates corresponding to the zero-crossing position of the differential confocal signal curve, further obtaining the position information of the upper and lower surfaces of the aspheric standard lens.

[0037] Furthermore, before step S1, a calibration step S0 is also included, and the step S0 is specifically:

[0038] S0. Adjust the first differential confocal measurement system and the second differential confocal measurement system respectively, so that the spot image signals on the tilt angle receiving devices are focused on the center positions of the corresponding tilt angle receiving devices.

[0039] The present invention also provides an optical axis angle measurement device, comprising a displacement device, a first five-axis displacement device, a second five-axis displacement device, a first differential confocal measurement system and a second differential confocal measurement system symmetrically arranged relative to the object to be measured;

[0040] The displacement device is used to move the object to be measured;

[0041] The first differential confocal measurement system and the second differential confocal measurement system are used to measure the upper surface and the lower surface of the object to be measured, respectively;

[0042] The first five-axis displacement device is used to move the first differential confocal measurement system so that the optical axis of the first differential confocal measurement system is aligned with the optical axis of the second differential confocal measurement system;

[0043] The second five-axis displacement device is used to move the second differential confocal measurement system so that the optical axis of the second differential confocal measurement system is aligned with the optical axis of the first differential confocal measurement system.

[0044] Further, the first differential confocal measurement system and the second differential confocal measurement system each include a laser light source, a first beam splitter, a microscope objective lens, a microscope objective lens driving device, a second beam splitter, a tilt angle receiving device, and a differential confocal assembly, which are sequentially arranged along the optical path;

[0045] The laser light source is used to emit measurement light beams of different wavelengths;

[0046] The first beam splitter and the second beam splitter are respectively used to split the light beam;

[0047] The microscope objective lens is used to focus the light beam on the upper surface and the lower surface of the object to be measured;

[0048] The microscope objective lens driving device is used to control the microscope objective lens to move along the direction of the light beam, thereby controlling the imaging position of the microscope objective lens on the upper surface and the lower surface of the object to be measured;

[0049] The tilt angle receiving device is used to receive the spot image signal and analyze the tilt angle;

[0050] The differential confocal component is used to receive a pre-focus light intensity signal and a post-focus light intensity signal and analyze position information.

[0051] Further, the differential confocal assembly includes a third beam splitter, a pre-focus focusing lens, a pre-focus pinhole, a pre-focus photodetector, a post-focus focusing lens, a post-focus pinhole, and a post-focus photodetector, which are sequentially arranged along the optical path;

[0052] The third beam splitter is used to split the measuring light beam;

[0053] The pre-focus focusing lens and the post-focus focusing lens are respectively used to focus the measuring light beam;

[0054] The pre-focus pinhole and the post-focus pinhole are respectively used for spatial filtering to block the out-of-focus light beam;

[0055] The pre-focus photodetector and the post-focus photodetector are used to receive the pre-focus light intensity signal and the post-focus light intensity signal, respectively.

[0056] The present invention can achieve the following technical effects:

[0057] 1. The optical axis angle measurement calibration device and method provided by the present invention can accurately solve the spatial vector of the optical axis of the differential confocal measurement system and the spatial coordinates of the focus on the surface of the object to be measured, and effectively and accurately adjust the position and tilt angle of the optical axis according to the solution results, and use the established function model and data analysis method to perform precise measurement.

[0058] 2. The optical axis angle measurement calibration device and method provided by the present invention compensate for the difference in refractive index between the upper and lower surfaces of the object under test through an algorithm, thereby eliminating the influence of the focus position change on the optical axis vector during the measurement process.

[0059] 3. The optical axis angle measurement calibration device and method provided by the present invention can accurately measure the spatial coordinates of each measuring point of the object to be measured when measuring the object to be measured in actual applications, and synchronously obtain the normal vector of the tangent plane where the measuring point is located and the two-dimensional tilt angle between the normal vector and the optical axis.

[0060] 4. The optical axis angle measurement calibration method provided by the present invention can ensure that the measuring light beam accurately illuminates the corresponding positions of the upper and lower surfaces of the object to be measured, and can truly reflect the actual situation of the surface of the object to be measured, thereby reducing the randomness and error of the measurement results.

[0061] 5. The optical axis angle measurement and calibration method provided by the present invention is simple and easy to implement, the measurement method is easy to operate, and both accuracy and speed are taken into account. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 is a schematic structural diagram of an optical axis angle measurement and calibration device according to an embodiment of the present invention;

[0063] Figure 2 is a schematic diagram of the principle of tilt angle measurement according to an embodiment of the present invention;

[0064] Figure 3 is a flow chart of a method for calibrating an optical axis angle measurement according to an embodiment of the present invention;

[0065] Figure 4 is a schematic diagram of a differential confocal curve according to an embodiment of the present invention;

[0066] Figure 5 Schematic diagram of measuring the upper surface and the lower surface of an aspheric standard lens by a first measuring beam and a second measuring beam according to an embodiment of the present invention.

[0067] Reference numerals include:

[0068] Laser light source-1, first beam splitter-2, microscope objective-3, microscope objective driving device-4, second beam splitter-5, tilt angle receiving device-6, third beam splitter-7, pre-focus focusing lens-8, pre-focus pinhole-9, pre-focus photoelectric detector-10, post-focus focusing lens-11, post-focus pinhole-12, post-focus photoelectric detector-13, object to be measured-14, first differential confocal measurement system-15, second differential confocal measurement system-16. DETAILED DESCRIPTION

[0069] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0070] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0071] The specific working mode of an optical axis angle measurement and calibration device and method according to an embodiment of the present invention is described in detail below with reference to the accompanying drawings:

[0072] Figure 1 A schematic structural diagram of an optical axis angle measurement and calibration device according to an embodiment of the present invention is shown.

[0073] Figure 2 A schematic diagram showing the principle of tilt angle measurement according to an embodiment of the present invention is shown.

[0074] Figure 3 A flow chart of a method for calibrating an optical axis angle measurement according to an embodiment of the present invention is shown.

[0075] Figure 4 A schematic diagram of a differential confocal curve according to an embodiment of the present invention is shown.

[0076] Figure 5 A schematic diagram showing the first measuring beam and the second measuring beam measuring the upper surface and the lower surface of the aspheric standard lens according to an embodiment of the present invention is shown.

[0077] Embodiment 1:

[0078] An embodiment of the present invention provides an optical axis angle measurement and calibration device, such as Figure 1As shown, it includes a first differential confocal measurement system 15, a second differential confocal measurement system 16, a displacement device for moving the object to be measured 14, a first five-axis displacement device, and a second five-axis displacement device. The first differential confocal measurement system 15 and the second differential confocal measurement system 16 are symmetrically arranged relative to the object to be measured 14. The first differential confocal measurement system 15 and the second differential confocal measurement system 16 are used to measure the upper surface and the lower surface of the object to be measured 14, respectively; the first five-axis displacement device is used to move the angle and position of the first differential confocal measurement system 15 so that the optical axis of the first differential confocal measurement system 15 is aligned with the optical axis of the second differential confocal measurement system 16; the second five-axis displacement device is used to move the angle and position of the second differential confocal measurement system 16 so that the optical axis of the second differential confocal measurement system 16 is aligned with the optical axis of the first differential confocal measurement system 15. In the embodiment of the present invention, the first differential confocal measurement system 15 and the second differential confocal measurement system 16 have the same structure. The embodiment of the present invention is described in detail by taking one of the differential confocal measurement systems, the first differential confocal measurement system 15, as an example. The first differential confocal measurement system 15 comprises a laser light source 1, a first beam splitter 2, a microscope objective 3, a microscope objective driving device 4, a second beam splitter 5, a tilt angle receiving device 6, a differential confocal assembly, and a displacement device, which are sequentially arranged along the optical path. The laser light source 1 is used to emit measurement beams of different wavelengths. In the embodiment of the present invention, the laser light source 1 can emit measurement beams of two wavelengths: a first measurement beam and a second measurement beam, the wavelength of the first measurement beam is 532nm, and the wavelength of the second measurement beam is 633nm. The first beam splitter 2 and the second beam splitter 5 are used to split the light beam respectively; the microscope objective 3 is used to focus the measuring light beam on the upper surface and the lower surface of the object 14 to be measured; the microscope objective driving device 4 is used to control the movement of the microscope objective 3 along the direction of the measuring light beam, and then control the imaging position of the microscope objective 3 on the upper surface and the lower surface of the object 14 to be measured; the tilt angle receiving device 6 is used to receive the spot image signal and analyze the tilt angle of the object 14 to be measured according to the spot image signal. The differential confocal component is used to receive the pre-focus light intensity signal and the post-focus light intensity signal, and analyze the position information according to the light intensity signal; the displacement device is used to move the object 14 to be measured. In the embodiment of the present invention, the differential confocal component includes a third beam splitter 7, a pre-focus focusing lens 8, a pre-focus pinhole 9, a pre-focus photodetector 10, a post-focus focusing lens 11, a post-focus pinhole 12, and a post-focus photodetector 13 arranged in sequence along the optical path. In the embodiment of the present invention, the tilt angle receiving device 6 is a two-dimensional lateral position detector or a planar array camera. The object 14 to be measured in the embodiment of the present invention is an aspherical standard lens.

[0079] In the embodiment of the present invention, the measurement order of the first measuring beam and the second measuring beam does not affect the measurement result. The larger the difference between the wavelengths of the two measuring beams within the range of 400nm-700nm, the better. The larger the wavelength difference, the greater the refractive index change when measuring the object 14, and the better the distinction of the light intensity signal collected later. In the embodiment of the present invention, the wavelength of the first measuring beam is 532nm, and the wavelength of the second measuring beam is 633nm. Other wavelengths of measuring beams can also be used for measurement according to actual conditions, and the present invention does not limit this. First, the first measuring beam with a wavelength of 532nm is used for the first measurement, and then the second measuring beam with a wavelength of 633nm is used for the second measurement. The laser light source 1 emits a first measuring beam with a wavelength of 532nm, and the first measuring beam is split by the first beam splitter 2. Among them, the transmitted light beam after the splitting is incident on the upper and lower surfaces of the aspheric standard lens through the microscope objective 3, and returns to the first beam splitter 2 along the original optical path after being reflected by the upper and lower surfaces, and the reflected light beam after the splitting by the first beam splitter 2 is incident on the second beam splitter 5. After being split by the second beam splitter 5, the reflected light beam is incident on the tilt angle receiving device 6; the transmitted light beam is incident on the third beam splitter 7. After being split by the third beam splitter 7, the reflected light beam is sequentially transmitted through the pre-focus focusing lens 8 and the pre-focus pinhole 9, and is received by the pre-focus photodetector 10; the transmitted light beam is sequentially transmitted through the post-focus focusing lens 11 and the post-focus pinhole 12, and is received by the post-focus photodetector 13.

[0080] The measurement process and principle of the second measuring beam in the embodiment of the present invention are the same as those of the first measuring beam, and are not described in detail here. The spot image signal on the tilt angle receiving device 6, the pre-focus light intensity signal on the pre-focus photodetector 10, and the post-focus light intensity signal on the post-focus photodetector 13 corresponding to the upper and lower surfaces measured by the first measuring beam and the second measuring beam are collected respectively, and the tilt angle information and position information of the upper and lower surfaces of the object to be measured 14 are obtained according to the collected signals. The measurement of the first differential confocal measurement system 15 is completed, and the measurement of the second differential confocal measurement system 16 is completed in the same way. According to the spot image signal, the pre-focus light intensity signal, and the post-focus light intensity signal collected by the first differential confocal measurement system 15 and the second differential confocal measurement system 16, a function model is constructed and solved, and the first absolute space coordinate of the focus of the upper surface, the absolute space vector of the optical axis of the first differential confocal measurement system 15, the second absolute space coordinate of the focus of the upper surface, and the absolute space vector of the optical axis of the second differential confocal measurement system 16 are solved.

[0081] The first five-axis displacement device is adjusted according to the first absolute spatial coordinate of the upper surface focus and the absolute spatial vector of the optical axis of the first differential confocal measurement system 15; the second five-axis displacement device is adjusted according to the second absolute spatial coordinate of the upper surface focus and the absolute spatial vector of the optical axis of the second differential confocal measurement system 16, so that the optical axis of the first differential confocal measurement system 15 and the optical axis of the second differential confocal measurement system 16 are aligned, and the first five-axis displacement device and the second five-axis displacement device are fixed after alignment. The aspheric standard lens is replaced with other objects to be measured 14, such as a CMOS detector. The CMOS detector is controlled to move by the displacement device, and the first differential confocal measurement system 15 and the second differential confocal measurement system 16 are used for measurement. When the displacement device moves, the first differential confocal measurement system 15 and the second differential confocal measurement system 16 respectively drive the microscope objective 3 to move through the microscope objective driving device 4 to obtain the differential confocal signal curve to measure the parallelism of the CMOS detector.

[0082] Embodiment 2:

[0083] The first differential confocal measurement system 15 and the second differential confocal measurement system 16 used in the embodiment of the present invention are the same, and the first differential confocal measurement system 15 is taken as an example for unified description. Figure 1 As shown, the first differential confocal measurement system 15 in the embodiment of the present invention includes a laser light source 1, a first beam splitter 2, a microscope objective 3, a microscope objective driving device 4, a second beam splitter 5, a tilt angle receiving device 6, a differential confocal component, and a displacement device, which are sequentially arranged along the optical path. The laser light source 1 is used to emit measurement beams of different wavelengths; the first beam splitter 2 and the second beam splitter 5 are used to split the beams respectively; the microscope objective 3 is used to focus the beam on the upper surface and the lower surface of the aspheric standard lens; the microscope objective driving device 4 is used to control the movement of the microscope objective 3 along the direction of the beam, and then control the imaging position of the microscope objective 3 on the upper surface and the lower surface of the aspheric standard lens; the tilt angle receiving device 6 is used to receive the spot image signal and analyze the tilt angle; the differential confocal component is used to receive the pre-focus light intensity signal and the post-focus light intensity signal and analyze the position information; the displacement device is used to move the aspheric standard lens. The material used for the aspheric standard lens in the embodiment of the present invention is quartz glass, and the refractive index of the aspheric standard lens is 1.46.

[0084] In the embodiment of the present invention, the upper surface and the lower surface of the aspheric standard lens are relative. The upper and lower surfaces are defined below. The upper surface and the lower surface are defined by the propagation of the measurement light beam of the differential confocal measurement system along the optical axis direction. The surface of the aspheric standard lens to which the measurement light beam first propagates is defined as the upper surface, and the surface of the aspheric standard lens to which the measurement light beam later propagates is defined as the lower surface. For the sake of clarity, in the subsequent explanations, when the first differential confocal measurement system 15 and the second differential confocal measurement system 16 perform measurements, the measurements are collectively referred to as the upper surface and the lower surface. For the embodiment of the present invention, the upper surface measured using the first differential confocal measurement system 15 is equivalent to the lower surface measured using the second differential confocal measurement system 16; the lower surface measured using the first differential confocal measurement system 15 is equivalent to the upper surface measured using the second differential confocal measurement system 16. Similarly, the upper surface measured by the second differential confocal measurement system 16 is equivalent to the lower surface measured by the first differential confocal measurement system 15 ; the lower surface measured by the second differential confocal measurement system 16 is equivalent to the upper surface measured by the first differential confocal measurement system 15 .

[0085] In the embodiment of the present invention, an absolute coordinate system is established by using an aspherical standard lens, such as Figure 2 As shown, represents the angle between the tangent plane normal vector and the optical axis of the first differential confocal measurement system 15 , and describes the inclination of the tangent plane normal vector in the Z direction of the optical axis of the first differential confocal measurement system 15 . It represents the rotation angle of the tangent plane normal vector in the plane, and describes the inclination angle of the tangent plane normal vector in the XY plane.

[0086] The embodiment of the present invention provides a method for measuring and calibrating the angle of an optical axis, which implements the angle measurement and calibration of the optical axis through a differential confocal measurement system. Figure 3 As shown, the following steps are included:

[0087] S0. Adjust the first differential confocal measurement system 15 and the second differential confocal measurement system 16 respectively, so that when there is no tilt angle, the spot image signal on the tilt angle receiving device 6 is focused on the center position of the corresponding tilt angle receiving device 6. This step is a calibration step, and other methods in the prior art can also be used to calibrate the first differential confocal measurement system 15 and the second differential confocal measurement system 16, which is not limited in the embodiment of the present invention.

[0088] S1. Place the aspheric standard lens between the first differential confocal measurement system 15 and the second differential confocal measurement system 16. The first differential confocal measurement system 15 and the second differential confocal measurement system 16 are symmetrically arranged relative to the aspheric standard lens. The aspheric standard lens used in the embodiment of the present invention is a standard part with clear specifications and specified specifications. The purpose of using standard parts is: when the differential confocal measurement system measures the inclination angles of the upper and lower surfaces of the aspheric standard lens and the position information is unique, a function model can be established to ultimately solve the relative position of the differential confocal measurement system and the measured standard part. Therefore, it is not necessarily an aspheric standard lens. As long as the curvature of the surface equation of the standard part is large and the curvature changes slowly, it can be identified as a plane in each local range, meeting the measurement requirements of the differential confocal measurement system. All standard lenses that meet these requirements are acceptable.

[0089] S2. Use the first differential confocal measurement system 15 and the second differential confocal measurement system 16 in sequence to measure the aspheric standard lens, wherein the measurement range includes: the upper surface and the lower surface of the aspheric standard lens, respectively obtain the inclination angle information and the position information of the upper surface and the lower surface, and construct and solve the function model based on the information.

[0090] S201, use the first differential confocal measurement system 15 to measure the aspheric standard lens. Place the aspheric standard lens in the first differential confocal measurement system 15, and first use the first measurement beam to measure the upper and lower surfaces of the aspheric standard lens. Then use the second measurement beam to measure the upper and lower surfaces of the aspheric standard lens. The measurement order of the first measurement beam and the second measurement beam does not affect the measurement result, but the greater the difference between the wavelengths of the two measurement beams in the range of 400nm-700nm, the better. The greater the wavelength difference, the greater the refractive index change when measuring the aspheric standard lens, and the easier it is to distinguish whether it is the signal of the upper surface or the signal of the lower surface when subsequently collecting the pre-focus light intensity signal and the post-focus light intensity signal of the upper and lower surfaces. In the embodiment of the present invention, the wavelength of the first measurement beam is 532nm, and the wavelength of the second measurement beam is 633nm. Measurement beams of other wavelengths can also be used for measurement according to actual conditions, and the present invention does not limit this.

[0091] S202, respectively collect the spot image signal, the pre-focus light intensity signal and the post-focus light intensity signal corresponding to the upper surface and the lower surface measured by the first measuring beam and the second measuring beam, and obtain the inclination angle information and position information of the upper surface and the lower surface according to the collected signals.

[0092] The method for obtaining the tilt angle information in the embodiment of the present invention is specifically: the peak position of the spot image signal and the tilt angle are matched one by one, the spot image signals of the upper surface and the lower surface of the aspheric standard lens on the tilt angle receiving device 6 are analyzed, and the tilt angle information of the upper surface and the lower surface of the aspheric standard lens is obtained. The method for obtaining the tilt angle information can also use the method of corresponding the spot centroid position offset and the angle offset in the prior art to obtain the angle tilt angle information, which is not limited in the embodiment of the present invention.

[0093] The method for obtaining the tilt angle information in the embodiment of the present invention is specifically as follows: placing the plane reflector in the first differential confocal measurement system 15, collecting the spot image signals on the tilt angle receiving device 6 corresponding to different tilt angles of the plane reflector, and recording the corresponding tilt angle and the corresponding peak position. Integrate the light intensity signals in the horizontal and vertical directions of each collected spot image signal respectively. Construct a function model of the peak position and tilt angle in the horizontal and vertical directions through polynomial fitting, and correspond the peak position and the tilt angle one by one. Then place the aspheric standard lens in the first differential confocal measurement system 15 to collect the spot image signal, and obtain the tilt angle information of the aspheric standard lens in the horizontal and vertical directions according to the function model. The tilt angle information obtained in the embodiment of the present invention is in the horizontal and vertical directions, that is, the tilt angle information from the X-axis and Y-axis directions, so it is necessary to merge the tilt angles in these two directions to realize the conversion of the two-dimensional tilt angle vector to the tilt angle and tilt direction, that is, to obtain the tilt angle information of the aspheric standard lens. .

[0094] ;

[0095] ;

[0096] in, Indicates the tilt angle information of the aspherical standard lens in the horizontal direction of the X axis; Indicates the tilt angle information of the aspherical standard lens in the vertical direction of the Y axis.

[0097] The method for obtaining position information in the embodiment of the present invention is as follows: using the collected pre-focus light intensity signal and post-focus light intensity signal, a differential confocal signal curve is obtained, and the position information of the upper and lower surfaces of the aspheric standard lens is obtained according to the coordinates corresponding to the zero-crossing position of the differential confocal signal curve. Figure 4As shown, the red curve is the pre-focus light intensity signal curve, the blue curve is the post-focus light intensity signal curve, the purple curve is the differential confocal signal curve, the distance between the two zero-crossing points, that is, the intersection of the purple curve and y=0, the two horizontal coordinates are the position information of the upper and lower surfaces of the aspheric standard lens, and the difference between the two horizontal coordinates is the thickness of the aspheric standard lens.

[0098] S203, constructing a function model, the function model at least includes: aspheric surface information, tilt angle information, position information, optical parameter information of the first differential confocal measurement system 15, the first absolute space coordinates of the upper surface focus, and the absolute space vector of the optical axis of the first differential confocal measurement system 15. Figure 5 As shown, it is a schematic diagram of the first measuring beam and the second measuring beam measuring the upper surface and the lower surface of the aspheric standard lens.

[0099] The construction function model is as follows:

[0100] First equation: The aspheric surface equation of the upper surface of the aspheric standard lens is shown in formula (1): f top (x,y,z)=0(1).

[0101] Since the aspheric standard lens is a standard part, the aspheric equation of the upper surface is known. The first absolute spatial coordinate of the upper surface focus to be solved satisfies the aspheric equation of the upper surface, which can ensure that the first absolute spatial coordinate of the upper surface focus obtained by the solution is indeed located on the upper surface.

[0102] Wherein, top represents the upper surface; (x, y, z) represents the first absolute spatial coordinate of the focus of the upper surface.

[0103] The first equation in the embodiment of the present invention is:

[0104] f top (x,y,z)= .

[0105] Second equation: The aspheric equation of the lower surface measured by the first measuring beam is shown in formula (2): (2).

[0106] The second equation in the embodiment of the present invention is:

[0107] ;

[0108] Since the aspheric standard lens is a standard part, the aspheric equation of the lower surface is known. Therefore, the absolute spatial coordinates of the lower surface measured by the first measuring beam satisfy the aspheric equation of the lower surface.

[0109] In the embodiment of the present invention, Figure 5As shown in FIG. 1 , when the first measuring beam with a wavelength of 532 nm is incident on the upper surface (x, y, z), the first measuring beam is refracted by the aspheric standard lens and focused on the lower surface ( ), formula (2) can be expressed as formula (3):

[0110] (3).

[0111] Wherein, λ1 represents the wavelength of the first measuring beam; Represents the refractive index of the aspheric standard lens for the first measurement beam; represents the thickness of the aspheric standard lens measured by the first measuring beam; ) represents the absolute spatial coordinates of the lower surface measured by the first measuring beam; Indicates the rotation angle of the normal vector of the tangent plane where the focus of the upper surface measured by the first measuring beam or the second measuring beam is located in the tangent plane; It represents the angle between the normal vector of the tangent plane at the focal point of the upper surface measured by the first measuring beam or the second measuring beam and the optical axis of the lower surface.

[0112] In the embodiment of the present invention, the material used for the aspheric standard lens is quartz glass with a refractive index of 1.46. The tilt angle measured at the focus of the upper surface is ; is 1.5 cm. Substituting the above values ​​into formula (3) gives:

[0113] .

[0114] The third equation: The aspheric equation of the lower surface measured by the second measuring beam is shown in formula (4): (4).

[0115] Similarly, since the aspheric standard lens is a standard part, the aspheric equation of the lower surface is known. Therefore, the absolute spatial coordinates of the lower surface measured by the second measuring beam satisfy the aspheric equation of the lower surface.

[0116] In the embodiment of the present invention, Figure 5 As shown in FIG. 1 , when the second measuring beam with a wavelength of 633 nm is incident on the upper surface (x, y, z), the second measuring beam is refracted by the aspheric standard lens and focused on the lower surface ( ), formula (4) can be expressed as formula (5):

[0117] (5).

[0118] Wherein, λ2 represents the wavelength of the second measuring beam; ) represents the absolute spatial coordinates of the lower surface measured by the second measuring beam; represents the refractive index of the aspheric standard lens for the second measuring beam; Indicates the thickness of the aspheric standard lens measured by the second measurement beam.

[0119] In the embodiment of the present invention, is 1.3 cm. Substituting the above value into formula (5) gives:

[0120] .

[0121] Fourth equation: The angle equation between the normal vector of the upper surface focus and the optical axis of the first differential confocal measurement system 15 is shown in formula (6):

[0122] . (i,o,p) =0(6).

[0123] Among them, the normal vector of the focus of the upper surface can be calculated by taking the partial derivative of the aspherical equation of the upper surface,

[0124] Right now .

[0125] The angle between the normal vector of the upper surface focus and the space vector of the optical axis of the first differential confocal measurement system 15 is and ,but .

[0126] Among them, top represents the upper surface; represents the normal vector of the focus of the upper surface; (i, o, p) represents the absolute space vector of the optical axis of the first differential confocal measurement system 15 on the upper surface; The absolute space vector of the optical axis of the first differential confocal measurement system 15 on the upper surface is .

[0127] Fifth equation: The angle equation between the focus normal vector of the lower surface measured by the first measuring beam and the optical axis of the first differential confocal measuring system 15 is shown in formula (7):

[0128] =0(7).

[0129] Among them, the focus normal vector of the lower surface measured by the first measuring beam can be obtained by the aspheric equation of the lower surface in ( ) and calculate the partial derivative.

[0130] Right now .

[0131] The angle between the focus normal vector of the lower surface measured by the first measuring beam and the optical axis of the first differential confocal measuring system 15 is ,but .

[0132] in, ;

[0133] in, .

[0134] Among them, bot represents the lower surface; An absolute space vector representing the refraction of the optical axis of the first differential confocal measurement system 15 at the lower surface measured by the first measurement beam; represents the absolute space vector of the refraction of the optical axis of the first differential confocal measurement system 15 on the lower surface under the measurement of the first measurement beam, that is, ; represents the focus normal vector of the lower surface measured by the first measuring beam; represents the rotation angle of the normal vector of the tangent plane where the focus of the lower surface measured by the first measuring beam is located within the tangent plane; represents the angle between the normal vector of the tangent plane at the focal point of the lower surface measured by the first measuring beam and the optical axis of the lower surface; Indicates rotating the absolute space vector (i,o,p) around the Y axis The rotation matrix of ; Indicates rotating the absolute space vector (i,o,p) around the Z axis The rotation matrix of ; Indicates that the absolute space vector (i,o,p) is rotated around the Z axis first , and then rotate around the Y axis The rotation matrix of .

[0135] In the embodiment of the present invention, after the first measuring beam is refracted by the aspheric standard lens, the measured inclination angle is = , = .

[0136] The sixth equation is the angle equation between the focus normal vector of the lower surface measured by the second measuring beam and the optical axis of the first optical probe, as shown in formula (8):

[0137] =0(8).

[0138] Among them, the focus normal vector of the lower surface measured by the second measuring beam can be obtained by the aspherical equation of the lower surface in ( ) and calculate the partial derivative.

[0139] Right now .

[0140] The angle between the focus normal vector of the lower surface measured by the second measuring beam and the optical axis of the first differential confocal measuring system 15 is ,but .

[0141] in, ;

[0142] in, .

[0143] in, represents the absolute space vector of the refraction of the optical axis of the first differential confocal measurement system 15 at the lower surface measured by the second measurement beam; represents the absolute space vector of the refraction of the optical axis of the first differential confocal measurement system 15 on the lower surface under the measurement of the second measurement beam, that is, ; represents the focus normal vector of the lower surface measured by the second measurement beam; represents the rotation angle of the normal vector of the tangent plane where the focus of the lower surface measured by the second measuring beam is located in this tangent plane; represents the angle between the normal vector of the tangent plane at the focal point of the lower surface measured by the second measuring beam and the optical axis of the lower surface; Indicates rotating the absolute space vector (i,o,p) around the Y axis The rotation matrix of ; Indicates rotating the absolute space vector (i,o,p) around the Z axis The rotation matrix of ; Indicates that the absolute space vector (i,o,p) is rotated around the Z axis first , and then rotate around the Y axis The rotation matrix of .

[0144] In the embodiment of the present invention, after the second measuring beam is refracted by the aspheric standard lens, the measured inclination angle is = , = .

[0145] The function model constructed in the embodiment of the present invention takes into account the situation that the tilt angle of the focus of the upper surface remains consistent under two measurement beams of different wavelengths. In the solution process, the influence of the refractive index change on the focus is corrected, and finally a complete and accurate spatial relationship function model is obtained. The technical solution in the embodiment of the present invention can provide a comprehensive and accurate function model for high-precision measurement by comprehensively considering the geometric relationship between the upper surface and the lower surface, the wavelength dependence of the refractive index and the influence of the focus offset.

[0146] S204 , solving the function model constructed in step S203 , and obtaining the first absolute space coordinates of the upper surface focus and the absolute space vector of the optical axis of the first differential confocal measurement system 15 .

[0147] The function model constructed in the embodiment of the present invention consists of 6 equations. The first three equations consist of the first absolute spatial coordinates (x, y, z) of the upper surface focus, that is, 3 unknowns. The last three equations consist of the first absolute spatial coordinates (x, y, z) of the upper surface focus and the absolute spatial vector (i, o, p) of the optical axis of the first differential confocal measurement system 15, that is, 6 unknowns. Among them, the refractive index of the aspheric standard lens, the spherical equations of the upper and lower surfaces of the aspheric standard lens, the thickness of the aspheric standard lens measured by the first measurement beam, the thickness of the aspheric standard lens measured by the second measurement beam, the rotation angle of the normal vector of the tangent plane at the upper surface focus measured by the first measurement beam or the second measurement beam in this tangent plane; the angle between the normal vector of the tangent plane at the upper surface focus measured by the first measurement beam or the second measurement beam and the optical axis of the lower surface are all known quantities, so the first absolute spatial coordinates of the upper surface focus, that is, (x, y, z), can be obtained through the first three equations. Substituting the first absolute spatial coordinate of the upper surface focus into the last three equations, the absolute spatial vector (i, o, p) of the optical axis of the first differential confocal measurement system 15 can be obtained.

[0148] The first equation, the second equation and the third equation in the embodiment of the present invention are solved together to obtain the following data:

[0149] (x,y,z)=(−0.628964, 0.656473, 0.989693);

[0150] ( ) = (−0.083664, 0.971273, 0.360093);

[0151] ( ) =(−0.125664,0.947073,0.408493).

[0152] Substituting the above data into the fourth, fifth and sixth equations, the following data are obtained by solving them simultaneously:

[0153] =(−1.5218, 1.5884, 1);

[0154] = (−0.1302, 1.5113, 1);

[0155] = (−0.2233, 1.6832, 1);

[0156] (i,o,p) = (−1.431, 1.5312, 0.9382).

[0157] S205 , using the first measuring beam and the second measuring beam to measure the aspheric standard lens through the second differential confocal measurement system 16 , repeating steps S202 - S204 , and obtaining the second absolute spatial coordinates of the upper surface focus and the absolute spatial vector of the optical axis of the second differential confocal measurement system 16 .

[0158] In the embodiment of the present invention, the principle of obtaining the second absolute spatial coordinates of the upper surface focus and the absolute spatial vector of the optical axis of the second differential confocal measurement system 16 through the second differential confocal measurement system 16 is the same as the principle of obtaining the first absolute spatial coordinates of the upper surface focus and the absolute spatial vector of the optical axis of the first differential confocal measurement system 15, and will not be repeated here.

[0159] S3. In the embodiment of the present invention, the adjustment according to the solution result in step S2 is specifically as follows: the first five-axis displacement device is adjusted according to the first absolute space coordinate of the upper surface focus and the absolute space vector of the optical axis of the first differential confocal measurement system 15, and the second five-axis displacement device is adjusted according to the second absolute space coordinate of the upper surface focus and the absolute space vector of the optical axis of the second differential confocal measurement system 16, so that the optical axis of the first differential confocal measurement system 15 and the optical axis of the second differential confocal measurement system 16 are aligned, and after alignment, the first five-axis displacement device and the second five-axis displacement device are fixed, that is, the angle measurement calibration of the optical axis is completed, and subsequent measurements can be performed. Subsequent measurements only need to replace the aspheric standard lens with other objects to be measured 14 for measurement. For example, a CMOS detector is controlled to move by a displacement device, and the first differential confocal measurement system 15 and the second differential confocal measurement system 16 are used for measurement. When the displacement device moves, the first differential confocal measurement system 15 and the second differential confocal measurement system 16 respectively drive the microscope objective 3 to move through the microscope objective driving device 4 to obtain the differential confocal signal curve to measure the parallelism.

[0160] The technical solution in the embodiment of the present invention uses the axial scanning technology of the differential confocal measurement system and the non-rotationally symmetric optical characteristics of the aspheric standard lens to accurately solve the spatial vector of the optical axis of the differential confocal measurement system and the spatial coordinates of the focus on the upper surface, and effectively and accurately adjusts the position and tilt angle of the optical axis according to the solution results, and uses the established function model and data analysis method to perform accurate measurement. The optical axis angle measurement calibration method provided by the present invention can not only be applied to the optical axis calibration before parallelism measurement, but also can be applied to other precision optical measurements and calibration of aspheric lenses. When measuring the object 14 in actual application, the differential confocal measurement system is used as an optical probe, and the spatial coordinates of each measurement point of the object 14 can be accurately measured at two different measurement wavelengths, and the normal vector of the tangent plane where the point is located and the two-dimensional tilt angle between the normal vector and the optical axis can be synchronously obtained. The optical axis angle measurement calibration method provided by the present invention can ensure that the optical axes of the optical probes on the upper and lower surfaces of the object 14 are aligned, and ensure that the points on the upper and lower surfaces of the object 14 correspond one to one, which is crucial to the accuracy and consistency of actual application measurement. The optical axis angle measurement calibration method provided by the present invention can ensure that the measurement light beam emitted by the differential confocal measurement system, i.e., the optical probe, accurately illuminates the corresponding positions of the upper and lower surfaces of the object to be measured 14, and can truly reflect the actual situation of the surface of the object to be measured 14, thereby reducing the randomness and error of the measurement results.

[0161] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0162] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0163] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for measuring and calibrating the angle of an optical axis, characterized in that: The angle measurement and calibration of the optical axis is achieved through a double differential confocal measurement system; The optical axis angle measurement calibration method comprises the following steps: S1, placing an aspheric standard lens between a first differential confocal measurement system (15) and a second differential confocal measurement system (16); S2, using the first differential confocal measurement system (15) and the second differential confocal measurement system (16) in sequence to measure the aspheric standard lens, wherein the measurement range includes: the upper surface and the lower surface of the aspheric standard lens, respectively obtaining the inclination angle information and the position information of the upper surface and the lower surface, and constructing and solving the function model according to the information; S3. According to the solution result, adjusting the angle and position of the optical axis of the first differential confocal measurement system (15) and the optical axis of the second differential confocal measurement system (16) to achieve angle measurement calibration of the optical axis; The measurement in step S2 is specifically: sequentially using a first measuring light beam and a second measuring light beam of different wavelengths to measure the upper surface and the lower surface of the aspheric standard lens; The measurement in step S2 is specifically: S201, using the first differential confocal measurement system (15), respectively using the first measurement beam and the second measurement beam to measure the aspheric standard lens; S202, respectively collecting the light spot image signal, the pre-focus light intensity signal and the post-focus light intensity signal corresponding to the upper surface and the lower surface measured by the first measuring light beam and the second measuring light beam on the inclination angle receiving device (6); and obtaining the inclination angle information and the position information of the upper surface and the lower surface according to the collected signals; S203, constructing a function model, wherein the function model at least includes: the aspheric surface information of the aspheric standard lens, the tilt angle information, the position information, the optical parameter information of the first differential confocal measurement system (15), the first absolute spatial coordinates of the upper surface focus, and the absolute spatial vector of the optical axis of the first differential confocal measurement system (15); S204, solving the function model to obtain the first absolute spatial coordinates of the upper surface focus and the absolute spatial vector of the optical axis of the first differential confocal measurement system (15); S205, using the second differential confocal measurement system (16), respectively using the first measurement beam and the second measurement beam to measure the aspheric standard lens, repeating steps S202-S204, and obtaining the second absolute spatial coordinates of the focus of the upper surface and the absolute spatial vector of the optical axis of the second differential confocal measurement system (16); In step S203, the function model constructed is specifically: First equation: The aspheric equation of the upper surface focus of the aspheric standard lens f top (x,y,z)=0; Second equation: The aspheric equation of the lower surface focus measured by the first measuring beam: Third equation: The aspheric equation of the lower surface focus measured by the second measuring beam: Fourth equation: The angle equation between the upper surface normal vector and the optical axis of the first differential confocal measurement system (15): Fifth equation: The angle equation between the focus normal vector of the lower surface measured by the first measuring light beam and the optical axis of the first differential confocal measurement system (15): in, Sixth equation: The angle equation between the focus normal vector of the lower surface measured by the second measuring beam and the optical axis of the first differential confocal measurement system (15): in, Wherein, top represents the upper surface; bot represents the lower surface; (x, y, z) represents the first absolute spatial coordinates of the focus of the upper surface; (x', y', z') represents the absolute spatial coordinates of the lower surface measured by the first measuring beam; (x", y", z") represents the absolute spatial coordinates of the lower surface measured by the second measuring beam; λ1 represents the first measuring beam; λ2 represents the second measuring beam; (i, o, p) represents the absolute spatial vector of the optical axis of the first differential confocal measurement system (15) on the upper surface; The absolute space vector representing the optical axis of the first differential confocal measurement system (15) on the upper surface is an absolute spatial vector representing the refraction of the optical axis of the first differential confocal measurement system (15) on the lower surface when the first measurement beam is measured; an absolute spatial vector representing the refraction of the optical axis of the first differential confocal measurement system (15) on the lower surface when the second measurement beam is measured; A normal vector representing the focus of the upper surface; a focus normal vector representing the lower surface measured by the first measuring beam; a focus normal vector representing the lower surface measured by the second measurement beam; represents the rotation angle of the normal vector of the tangent plane at the focal point of the upper surface measured by the first measuring beam or the second measuring beam within the tangent plane; θ1 represents the angle between the normal vector of the tangent plane at the focal point of the upper surface measured by the first measuring beam or the second measuring beam and the optical axis of the lower surface; represents the rotation angle of the normal vector of the tangent plane where the focus of the lower surface measured by the first measuring beam is located within the tangent plane; represents the angle between the normal vector of the tangent plane at the focus of the lower surface measured by the first measuring light beam and the optical axis of the lower surface; represents the rotation angle of the normal vector of the tangent plane where the focus of the lower surface measured by the second measuring beam is located within the tangent plane; represents the angle between the normal vector of the tangent plane at the focus of the lower surface measured by the second measuring beam and the optical axis of the lower surface; Indicates rotating the absolute space vector (i,o,p) around the Y axis The rotation matrix of Indicates rotating the absolute space vector (i,o,p) around the Z axis The rotation matrix of Indicates rotating the absolute space vector (i,o,p) around the Y axis The rotation matrix of Indicates rotating the absolute space vector (i,o,p) around the Z axis The rotation matrix of Indicates that the absolute space vector (i,o,p) is rotated around the Z axis first Rotate around the Y axis The rotation matrix of Indicates that the absolute space vector (i,o,p) is rotated around the Z axis first Then rotate around the Y axis The rotation matrix of .

2. The angle measurement calibration method according to claim 1, characterized in that: The method for obtaining the inclination angle information and position information of the upper surface and the lower surface in step S202 is specifically as follows: A method for obtaining tilt angle information: a peak position of the light spot image signal and the tilt angle are matched one by one, the light spot image signals of the upper surface and the lower surface of the aspheric standard lens on the tilt angle receiving device (6) are analyzed, and the tilt angle information of the upper surface and the lower surface of the aspheric standard lens is obtained; Method for obtaining position information: using the collected pre-focus light intensity signal and the post-focus light intensity signal to obtain a differential confocal signal curve, and obtaining the position information of the upper and lower surfaces of the aspheric standard lens according to the coordinates corresponding to the zero-crossing position of the differential confocal signal curve.

3. The angle measurement calibration method according to claim 1, characterized in that: The step S1 also includes a calibration step S0, and the step S0 is specifically as follows: Step S0: respectively adjusting the first differential confocal measurement system (15) and the second differential confocal measurement system (16) so that the light spot image signals on the tilt angle receiving device (6) are focused on the center position of the corresponding tilt angle receiving device (6).

4. An angle measurement calibration device that uses the angle measurement calibration method of the optical axis as claimed in claim 1 to achieve angle measurement calibration, characterized in that: It comprises a displacement device, a first five-axis displacement device, a second five-axis displacement device, a first differential confocal measurement system (15) and a second differential confocal measurement system (16) which are symmetrically arranged relative to the object to be measured (14); The displacement device is used to move the object to be measured (14); The first five-axis displacement device is used to move the angle and position of the first differential confocal measurement system (15) so that the optical axis of the first differential confocal measurement system (15) is aligned with the optical axis of the second differential confocal measurement system (16); The second five-axis displacement device is used to move the angle and position of the second differential confocal measurement system (16) so that the optical axis of the second differential confocal measurement system (16) is aligned with the optical axis of the first differential confocal measurement system (15); The first differential confocal measurement system (15) and the second differential confocal measurement system (16) are used to measure the upper surface and the lower surface of the object to be measured (14), respectively.

5. The angle measurement calibration device according to claim 4, characterized in that: The first differential confocal measurement system (15) and the second differential confocal measurement system (16) both comprise a laser light source (1), a first beam splitter (2), a microscope objective lens (3), a microscope objective lens driving device (4), a second beam splitter (5), a tilt angle receiving device (6), and a differential confocal component, which are sequentially arranged along an optical path; The laser light source (1) is used to emit measurement light beams of different wavelengths; The first beam splitter (2) and the second beam splitter (5) are respectively used to split the measuring light beam; The microscope objective lens (3) is used to focus the measuring light beam on the upper surface and the lower surface of the measured object (14); The microscope objective lens driving device (4) is used to control the microscope objective lens (3) to move along the direction of the measuring light beam, thereby controlling the imaging position of the microscope objective lens (3) on the upper surface and the lower surface of the measured object (14); The tilt angle receiving device (6) is used to receive the light spot image signal and then analyze the tilt angle; The differential confocal component is used to receive a pre-focus light intensity signal and a post-focus light intensity signal, and then analyze the position information.

6. The angle measurement calibration device according to claim 5, characterized in that: The differential confocal assembly comprises a third beam splitter (7), a pre-focus focusing lens (8), a pre-focus pinhole (9), a pre-focus photoelectric detector (10), a post-focus focusing lens (11), a post-focus pinhole (12), and a post-focus photoelectric detector (13) which are sequentially arranged along the optical path; The third beam splitter (7) is used to split the measuring light beam; The pre-focus focusing lens (8) and the post-focus focusing lens (11) are respectively used to focus the measuring light beam; The pre-focus pinhole (9) and the post-focus pinhole (12) are respectively used for spatial filtering to block out-of-focus light beams; The pre-focus photoelectric detector (10) and the post-focus photoelectric detector (13) are used to receive the pre-focus light intensity signal and the post-focus light intensity signal, respectively.

Images