A method and device for calibrating a wedge angle of a wedge and a storage medium

Abstract

The application discloses a kind of optical wedge wedge angle calibration method, device and storage medium, it is related to optical measurement technical field.The optical wedge wedge angle calibration method is used to carry out wedge angle calibration to the optical wedge of single crystal material, and the calibration method includes the following steps: the geometric surface of optical wedge is scanned using scanning electron microscope to obtain scanning image, the light intensity distribution diagram corresponding to scanning image is extracted, each period of light intensity distribution diagram corresponds to the lattice period of surface, according to the number relationship between light intensity period and pixel point, the size of geometric surface is traced to the lattice period size of micro, then the optical wedge wedge angle value can be calculated by the geometric relationship of surface measurement line;Since the surface size of optical wedge is calculated in the application, the lattice period size is calculated from lattice constant according to the geometric relationship of single crystal silicon lattice, and the lattice constant of single crystal material is a known quantity with extremely high precision, so the optical wedge wedge angle calibration method proposed in the application has extremely high precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical measurement technology, and in particular to a method and device for calibrating the wedge angle of an optical wedge, and a storage medium. BACKGROUND

[0002] An optical wedge, which is widely used in the field of optics, is composed of two non-parallel optical working surfaces, and the included angle between the two surfaces is referred to as the wedge angle. The optical wedge can cause a small-angle deflection of a light beam, thereby changing the direction of light propagation, and plays an important role in a light path guiding system. A system composed of two optical wedges with the same refractive index and the same wedge angle can not only realize the function of a single optical wedge, but also be used for light spot shaping and realizing arbitrary-angle deflection of light within a certain angle range. Based on these characteristics, the optical wedge is widely used in many fields such as high-precision angle generators, laser micro-hole machining light path control, laser radar systems, and test systems for inter-satellite laser communication.

[0003] In the manufacturing process of an optical wedge, accurate measurement of the wedge angle is a key link to ensure the quality and performance of the optical wedge. Traditional methods for measuring the wedge angle of an optical wedge mainly rely on autocollimator angle measurement and equal-thickness interference. In the autocollimator angle measurement method, a collimated light beam is emitted by an autocollimator to be projected at a near-perpendicular angle to the optical wedge. The front surface and the rear surface of the optical wedge reflect the collimated light beam back to the autocollimator, respectively, and form images in the autocollimator. The wedge angle of the optical wedge is calculated by using the position difference between the two images and the focal length of the autocollimator. This method is essentially based on the principle of optical autocollimation. The measurement accuracy of the optical autocollimation principle is generally in the order of sub-arcsecond (10 -7 rad), which is difficult to further improve. In the equal-thickness interference method, a collimated laser beam is irradiated on the optical wedge, and interference fringes are formed by the reflected laser beams from the front surface and the rear surface of the optical wedge. The wedge angle of the optical wedge is calculated by measuring the distance between the interference fringes. The measurement accuracy of this method can reach the order of tens of nanoradians (10 - 8 rad), but the accuracy is difficult to further improve due to the measurement accuracy of the distance between the interference fringes and the noise of the laser wavelength. SUMMARY

[0004] The present application provides a method and device for calibrating the wedge angle of an optical wedge, and a storage medium, aiming to calibrate the wedge angle of the optical wedge with high accuracy.

[0005] The optical wedge to be calibrated has a single-crystal material, and includes a first optical working surface, a second optical working surface, a top surface, and a bottom surface. The top surface and the bottom surface are arranged in parallel. The first optical working surface and the second optical working surface are respectively connected to opposite edges of the top surface and the bottom surface. The first optical working surface is perpendicular to the top surface and is arranged non-parallel to the second optical working surface.

[0006] The wedge angle calibration method of the optical wedge comprises the following steps:

[0007] S1, scanning electron microscopy is used to scan the top surface and the bottom surface along the x-axis direction to obtain scanning images; the x-axis is perpendicular to the first optical working surface;

[0008] S2, the light intensity distribution diagram of the scanning image of the top surface and the bottom surface in the x-axis direction is extracted respectively, the number of pixel points corresponding to each period of the light intensity distribution diagram of the top surface and the bottom surface is counted, and the number of pixel points contained in the scanning image of the top surface and the bottom surface in the x-axis direction is counted, and the size x1 of the top surface in the x-axis direction and the size x2 of the bottom surface in the x-axis direction are calculated according to the following formula respectively:

[0009] x1=N1·C1 / n1;x2=N2·C1 / n2;

[0010] In the formula, C1 represents the lattice period size of the top surface or the bottom surface of the optical wedge; n1 and n2 respectively represent the number of pixel points corresponding to each period in the light intensity distribution diagram of the top surface and the bottom surface of the optical wedge, and N1 and N2 respectively represent the number of pixel points contained in the scanning image of the top surface and the bottom surface of the optical wedge in the x-axis direction;

[0011] S3, the size h of the first optical working surface in the z-axis direction is obtained; the z-axis is perpendicular to the top surface;

[0012] S4, the wedge angle α of the optical wedge is calculated according to the following formula:

[0013] α=arctan(|x2-x1| / h)。

[0014] Optionally, the material of the optical wedge is monocrystalline silicon.

[0015] Optionally, the top surface and the bottom surface are parallel to the {111} crystal surface of monocrystalline silicon, and the lattice period size C1 of the top surface and the bottom surface of the optical wedge is 0.314 nm.

[0016] Optionally, the size h of the first optical working surface in the z-axis direction is obtained by the following steps:

[0017] S31, scanning electron microscopy is used to scan the first optical working surface along the z-axis direction to obtain a scanning image;

[0018] S32, the light intensity distribution diagram of the scanning image of the first optical working surface in the z-axis direction is extracted, the number of pixel points n corresponding to each period of the light intensity distribution diagram of the first optical working surface is counted h , and the number of pixel points N contained in the scanning image of the first optical working surface in the z-axis direction is counted h; the size h of the first optical working surface in the z-axis direction is calculated according to the following formula:

[0019] h = N h · C2 / n h ;

[0020] In the formula, C2 represents the lattice period size of the first optical working surface of the optical wedge.

[0021] Optionally, the size h of the first optical working surface in the z-axis direction is obtained by measurement with an optical profiler, an optical microscope, a laser interferometer, a laser scanning microscope or an atomic force microscope.

[0022] Based on the above wedge angle calibration method of the optical wedge, the application further provides an optical wedge wedge angle calibration device, which comprises:

[0023] A scanning electron microscope configured to perform image scanning on the surface of the optical wedge in a preset direction to obtain a scanning image;

[0024] An image processing module configured to extract an optical intensity distribution diagram of the scanning image in the preset direction;

[0025] A pixel counting module for counting the number of pixel points corresponding to each period of the optical intensity distribution diagram and counting the number of pixel points of the scanning image in the preset direction;

[0026] A calculation module for calculating the size x1 of the top surface of the optical wedge in the x-axis direction and the size x2 of the bottom surface of the optical wedge in the x-axis direction according to the following formula:

[0027] x1 = N1·C1 / n1; x2 = N2·C1 / n2;

[0028] In the formula, C1 represents the lattice period size of the top surface or the bottom surface of the optical wedge; n1 and n2 respectively represent the number of pixel points corresponding to each period in the optical intensity distribution diagram of the top surface and the bottom surface of the optical wedge, and N1 and N2 respectively represent the number of pixel points contained in the scanning image of the top surface and the bottom surface of the optical wedge in the x-axis direction;

[0029] And the wedge angle α of the optical wedge is calculated according to the following formula:

[0030] α = arctan(|x2-x1| / h);

[0031] In the formula, h represents the size of the first optical working surface of the optical wedge in the z-axis direction.

[0032] Optionally, the size h of the first optical working surface in the z-axis direction is calculated according to the following formula:

[0033] h = N h · C2 / n h ;

[0034] In the formula, C2 represents the lattice period size of the first optical working surface of the wedge, n h N is the number of pixel points corresponding to each period of the light intensity distribution map of the first optical working surface of the wedge, h N is the number of pixel points contained in the scanning image of the first optical working surface of the wedge in the z-axis direction.

[0035] Optionally, the wedge angle calibration device further comprises an optical measurement module, the optical measurement module being configured to measure the size h of the first optical working surface in the z-axis direction, and the optical measurement module comprises at least one of an optical profiler, an optical microscope, a laser scanning microscope and an atomic force microscope.

[0036] Optionally, the wedge angle calibration device further comprises an error analysis module;

[0037] The error analysis module is configured to calculate the calibration error of the wedge angle according to an error transfer function; and the error transfer function is:

[0038]

[0039] In the formula, C2 represents the lattice period size of the first optical working surface of the wedge, n represents the error value of the wedge angle, represents the error value of x1, represents the error value of x2, represents the error value of h.

[0040] The application further provides a computer storage medium, which stores a computer program, and the computer program can realize the wedge angle calibration method when executed by a processor.

[0041] The application has the following beneficial effects:

[0042] ​The atoms on the geometric surface of the monocrystalline material optical wedge are strictly arranged in order according to the crystal lattice period, forming a periodic electric potential field distribution, the scanning electron microscope scans the surface of the optical wedge through the incident electron beam, the interaction intensity between the incident electron beam and the surface of the optical wedge will change periodically with the periodic arrangement of the atoms, and the periodic peak and valley fluctuation in the light intensity distribution diagram is reflected through the secondary electron imaging, and each fluctuation period corresponds to a lattice period of the geometric surface of the optical wedge; the application utilizes the advantages of high-resolution imaging of the scanning electron microscope, scans the geometric surface of the monocrystalline material optical wedge through the scanning electron microscope, extracts the light intensity distribution diagram, and according to the number relationship between the light intensity period and the pixel points, the size of the geometric surface is traced back to the microcrystalline lattice period size, and then the wedge angle value of the optical wedge is calculated through the geometric relationship of the surface measurement line, the lattice period size of the monocrystalline material is calculated from the lattice constant, and since the lattice constant of the monocrystalline material is a known quantity with extremely high precision, the wedge angle value of the monocrystalline material optical wedge measured by the optical wedge wedge angle calibration method provided by the application has extremely high precision, and the error is as low as 10 -10 The order of magnitude of the arc is radian, and the precision is much higher than that of the traditional autocollimator angle measurement method and the equal-thickness interference method. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0044] Figure 1 The flowchart of some embodiments of the optical wedge wedge angle calibration method of the present application;

[0045] Figure 2 The structural schematic diagram of the optical wedge to be measured of the present application;

[0046] Figure 3 The principle schematic diagram of scanning the surface of the optical wedge by the scanning electron microscope of the present application;

[0047] Figure 4 The test principle schematic diagram of some embodiments of the optical wedge wedge angle calibration method of the present application;

[0048] Figure 5 The single-crystal silicon optical wedge surface scanning image and the corresponding x-direction light intensity distribution diagram obtained by the scanning electron microscope of some embodiments of the present application.

[0049] The reference signs are explained as follows: 1, top surface; 2, bottom surface; 3, first optical working surface; 4, second optical working surface. DETAILED DESCRIPTION

[0050] In order to make the application purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the embodiments described below are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0051] The terms "first", "second", "third", "fourth" and the like in the description and drawings of the present application, if any, are used to distinguish similar objects, and do not necessarily imply a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units need not be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0052] Referring to Figure 2 The optical wedge calibrated in the embodiments of the present application includes a first optical working surface 3, a second optical working surface 4, a top surface 1 and a bottom surface 2. The top surface 1 and the bottom surface 2 are arranged in parallel. The first optical working surface 3 and the second optical working surface 4 are respectively connected to opposite edges of the top surface 1 and the bottom surface 2. The first optical working surface 3 is perpendicular to the top surface 1 and is arranged non-parallel to the second optical working surface 4. The included angle α of the first optical working surface 3 and the second optical working surface 4 is the wedge angle of the optical wedge.

[0053] It should be noted that before scanning and measuring the optical wedge, the oxide layers on the top surface and the bottom surface of the optical wedge need to be polished and removed. The "top surface" and "bottom surface" mentioned in the embodiments of the present application refer to the top surface and the bottom surface of the optical wedge after polishing and removing the oxide layers.

[0054] The optical wedge calibrated in the embodiments of the present application is of single crystal material, including but not limited to single crystal silicon, single crystal germanium, single crystal gallium arsenide, metal single crystal, ionic crystal single crystal (such as calcium fluoride, etc.). The single crystal material is characterized by highly ordered atomic arrangement. The atoms are strictly ordered according to the crystal lattice period on the geometric surface, and the crystal lattice period size is calculated from the crystal lattice constant, which is a known quantity with extremely high precision (for example, the crystal lattice constant of single crystal silicon is accurately calibrated by the International Union of Crystallography as 0.5431 nm (25℃), with an error as low as 10 -8 nm order).

[0055] Referring to Figure 3The scanning electron microscope (SEM) emits an electron beam through an electron gun, the electron beam forms an incident electron beam after passing through a converging coil, a deflection coil and a focusing coil and irradiates on the sample surface, the incident electron beam interacts with the atoms on the sample surface to excite secondary electrons, the incident electron beam scans on the sample surface in a certain spatial and time sequence, the secondary electrons are detected by a secondary electron detector and converted into optical signals, the optical signals are converted into electrical signals by an amplifier and amplified, and finally a scanning image reflecting the sample surface topography is presented on a display; since the secondary electrons are formed by the outer electrons near the atomic nucleus under the action of the incident electron beam and are bound to the atomic nucleus, therefore, more secondary electrons are emitted from the atomic dense place (lattice site), which shows high light intensity, and fewer secondary electrons are emitted from the gap between the lattice sites, which shows low light intensity; for a single crystal material sample, since the atoms on the sample surface are arranged in strict periodicity, therefore, the light intensity distribution of the scanning image changes periodically with the periodic arrangement of the atoms, and each fluctuation period corresponds to a lattice period of the optical wedge geometric surface; the scanning electron microscope preferably a high-precision field emission scanning electron microscope.

[0056] The optical wedge wedge angle calibration method provided by the application combines the above-mentioned characteristics of single crystal material and scanning electron microscope, traces the geometric size of the optical wedge surface to the micro-lattice size of the single crystal material, and thus measures the wedge angle of the optical wedge with high precision.

[0057] Referring to Figure 1 and Figure 4 In some embodiments, the optical wedge wedge angle calibration method provided by the application comprises the following steps S1-S4:

[0058] S1, using a scanning electron microscope to respectively perform image scanning on the top surface and the bottom surface along the x-axis direction to obtain scanning images; the x-axis is perpendicular to the first optical working surface.

[0059] Since the top surface and the bottom surface of the optical wedge are parallel surfaces of single crystal material, the top surface and the bottom surface have the same lattice period size; the scanning electron microscope obtains the scanning images of the top surface and the bottom surface of the optical wedge through secondary electron imaging.

[0060] S2, respectively extracting the light intensity distribution graphs of the top surface and the bottom surface scanning images in the x-axis direction, counting the number of pixel points corresponding to each period of the light intensity distribution graphs of the top surface and the bottom surface, and counting the number of pixel points contained in the scanning images of the top surface and the bottom surface in the x-axis direction, and calculating the size x1 (the length of the measurement line 1) of the top surface in the x-axis direction and the size x2 (the length of the measurement line 3) of the bottom surface in the x-axis direction according to the following formula respectively:

[0061] x1=N1·C1 / n1;x2=N2·C1 / n2;

[0062] In the formula, C1 represents the lattice period size of the top surface or bottom surface of the optical wedge; n1 and n2 represent the number of pixel points corresponding to each period in the light intensity distribution map of the top surface and bottom surface of the optical wedge, respectively; and N1 and N2 represent the number of pixel points contained in the scanning image of the top surface and bottom surface of the optical wedge in the x-axis direction, respectively.

[0063] This step converts the size of the top surface and bottom surface of the optical wedge into the multiple of the lattice period size through the number of pixel points, and the lattice period size C1 can be calculated from the lattice constant according to the mathematical geometric relationship of the crystal structure of the single crystal material.

[0064] S3, obtaining the size h of the first optical working surface in the z-axis direction (the length of the measurement line 2); the z-axis is perpendicular to the top surface.

[0065] In some preferred embodiments, h can be measured by referring to the method for measuring x1 and x2 in step S2, specifically: S31, performing image scanning on the first optical working surface along the z-axis direction by using a scanning electron microscope to obtain a scanning image; S32, extracting the light intensity distribution map of the scanning image of the first optical working surface in the z-axis direction, counting the number of pixel points n h corresponding to each period of the light intensity distribution map of the first optical working surface, and counting the number of pixel points N h contained in the scanning image of the first optical working surface in the z-axis direction; and calculating the size h of the first optical working surface in the z-axis direction according to the following formula:

[0066] h=N h ·C2 / n h ;

[0067] In the formula, C2 represents the lattice period size of the first optical working surface of the optical wedge, which can be calculated from the lattice constant according to the mathematical geometric relationship of the crystal structure of the single crystal material.

[0068] In some other embodiments, since the value of h of the optical wedge is much larger than x1 and x2 (several times or even more than ten times), the influence of the wedge angle calibration error is small, and the value of h can also be measured by ordinary optical measurement method, for example, by using devices such as optical profilometer, optical microscope, laser interferometer, laser scanning microscope or atomic force microscope to measure and obtain the value of h.

[0069] S4, after the values of x1, x2 and h are measured, the wedge angle α of the optical wedge is calculated according to the trapezoidal geometric relationship determined by x1, x2 and h, and according to the following formula:

[0070] α=arctan(|x2-x1| / h).

[0071] Due to the strict order arrangement of atoms on the geometric surface of the single crystal material wedge according to the crystal lattice period, a periodic potential field distribution is formed. The scanning electron microscope scans the surface of the wedge by the incident electron beam. The interaction intensity between the incident electron beam and the surface of the wedge changes periodically with the periodic arrangement of atoms. The periodic peak and valley fluctuation in the light intensity distribution diagram is reflected by the secondary electron imaging. Each fluctuation period corresponds to a lattice period of the geometric surface of the wedge.

[0072] The embodiment of the present application utilizes the high resolution imaging advantage of the scanning electron microscope. The geometric surface of the single crystal material wedge is scanned and imaged by the scanning electron microscope. The light intensity distribution diagram is extracted. The size of the geometric surface is traced back to the microscopic lattice period size according to the number relationship between the light intensity period and the pixel point. Then, the wedge angle value of the wedge is calculated through the geometric relationship. The lattice period size of the single crystal material is calculated from the lattice constant. Since the lattice constant of the single crystal material is a known quantity with extremely high precision, the single crystal material wedge wedge angle value measured by the wedge angle calibration method provided by the present application has extremely high precision.

[0073] Based on the above embodiment, in order to better illustrate the implementation process and beneficial effects of the technical scheme of the present application, the present application further proposes the following specific embodiments. It should be noted that the following specific embodiments are only exemplary in nature and do not limit the scope of protection of the present application in any form.

[0074] Embodiment 1

[0075] Step 1, using single crystal silicon material to make a wedge, the crystal of single crystal silicon is face-centered cubic diamond structure, the lattice constant is 0.5431 nm (25℃), the top surface and the bottom surface of the wedge are parallel to the {111} crystal surface of single crystal silicon, which is a regular triangular close packing, and the lattice period size of the top surface and the bottom surface is .

[0076] Step 2, place the wedge with the top surface upward on the sample stage of the scanning electron microscope, and scan the top surface of the wedge along the x-axis direction by the incident electron beam to obtain a two-dimensional scanning image, as shown in Figure 5 .

[0077] Step 3, extract the light intensity distribution diagram of the two-dimensional scanning image of the top surface of the wedge, as shown in Figure 5 , the light intensity distribution curve is a peak-valley curve fluctuating periodically along the scanning direction, and each period of the light intensity distribution curve corresponds to a lattice period C1 of the {111} crystal surface of single crystal silicon.

[0078] Step 4, the average number of pixels n1 corresponding to each period in the top surface light intensity distribution is counted, and the pixel spacing size of the top surface two-dimensional scanning image is C1 / n1; the total number of pixels N1 contained in the x-axis direction of the top surface two-dimensional scanning image is counted, and the size x1 of the optical wedge top surface in the x-axis direction is obtained.

[0079] Step 5, the bottom surface and the first optical working surface of the optical wedge are placed horizontally upwards on the sample table of the scanning electron microscope in turn, and the method of steps 2-4 is repeated to calculate the size x2 of the bottom surface in the x-axis direction x2=N2·C1 / n2 and the size h of the first optical working surface in the z-axis direction h=N2·C2 / n2. h h .

[0080] Step 6, x1, x2 and h form a trapezoidal geometric relationship, and the wedge angle α of the optical wedge is calculated according to the trapezoidal geometric relationship arctan(|x2-x1| / h).

[0081] The error transfer function of the trapezoidal geometric relationship is:

[0082] ;

[0083] In the formula, represents the wedge angle error value, represents the error value of x1, represents the error value of x2, represents the error value of h.

[0084] Taking the top surface or bottom surface lattice period size C1=0.314nm of single crystal silicon as an example, the resolution of a commonly used scanning electron microscope is 1nm, according to the scanning electron microscope image, the size x1 of the optical wedge top surface in the x-axis direction is 5mm, and the error value =0.03nm (because the sizes of x1 and x2 are obtained by combining the scanning electron microscope image with the silicon lattice period size, the error value is set as 0.03nm according to 1 / 10 of the silicon lattice period size, which is easy to realize in the precision measurement scheme of the present application, and the error value of x2 is the same); the size x2 of the bottom surface in the x-axis direction is 5mm+50nm, and the error value =0.03nm; the size h of the first optical working surface in the z-axis direction is 5cm, and the error value =50nm (the size h can be measured by a laser interferometer or the like, and the error value is set as 10 -6 % of the actual size, which is easy to realize in the precision measurement scheme of the present application); the wedge angle α of the optical wedge is calculated as 1×10 -6 rad, and the error value =8.5×10 -10 ​rad; it can be known from the above embodiment that the wedge angle error obtained by using the wedge angle calibration method provided by the application can be as low as 10 -10 The angle is in radian, and the calibration accuracy is much higher than that of the traditional autocollimator angle measurement method and the equal-thickness interference method.

[0085] Based on the wedge angle calibration method, the application further provides a wedge angle calibration device.

[0086] In some embodiments, the wedge angle device comprises a scanning electron microscope, an image processing module, a pixel counting module and a calculation module.

[0087] The scanning electron microscope is configured to perform image scanning on the surface of the optical wedge in a preset direction to obtain a scanning image.

[0088] The image processing module is configured to extract an optical intensity distribution diagram of the scanning image in the preset direction.

[0089] The pixel counting module is used to count the number of pixel points corresponding to each period of the optical intensity distribution diagram and the number of pixel points of the scanning image in the preset direction.

[0090] The calculation module is used to calculate the size x1 of the top surface of the optical wedge in the x-axis direction and the size x2 of the bottom surface of the optical wedge in the x-axis direction according to the following formula:

[0091] x1=N1·C1 / n1; x2=N2·C1 / n2;

[0092] In the formula, C1 represents the lattice period size of the top surface or the bottom surface of the optical wedge; n1 and n2 represent the number of pixel points corresponding to each period in the optical intensity distribution diagram of the top surface and the bottom surface of the optical wedge, respectively; N1 and N2 represent the number of pixel points contained in the scanning image of the top surface and the bottom surface of the optical wedge in the x-axis direction, respectively.

[0093] And the wedge angle α of the optical wedge is calculated according to the following formula:

[0094] α=arctan(|x2-x1| / h);

[0095] In the formula, h represents the size of the first optical working surface of the optical wedge in the z-axis direction.

[0096] In some preferred embodiments, the calculation module further calculates the size h of the first optical working surface in the z-axis direction according to the following formula:

[0097] h=N h ·C2 / n h ;

[0098] In the formula, C2 represents the lattice period size of the first optical working surface of the optical wedge, and n hN is the number of pixel points corresponding to each period of the light intensity distribution diagram of the first optical working surface of the optical wedge h N is the number of pixel points contained in the scanning image of the first optical working surface of the optical wedge in the z-axis direction.

[0099] In some other embodiments, the optical wedge wedge angle calibration device further comprises an optical measurement module, the optical measurement module is configured to measure the size h of the first optical working surface in the z-axis direction, and the optical measurement module comprises at least one of an optical profiler, an optical microscope, a laser scanning microscope, and an atomic force microscope.

[0100] In some embodiments, the optical wedge wedge angle calibration device further comprises an error analysis module; the error analysis module is configured to calculate the calibration error of the wedge angle of the optical wedge according to an error transfer function; the error transfer function is:

[0101] ;

[0102] In the formula, represents the wedge angle error value, represents the error value of x1, represents the error value of x2, represents the error value of h.

[0103] The application further provides a computer storage medium, which stores a computer program, and the computer program can realize the above optical wedge wedge angle calibration method when executed by a processor.

[0104] In several embodiments provided by the present application, it should be understood that the disclosed device and method can be implemented by other manners. For example, the above-described device embodiments are only illustrative, for example, the division of the units / modules is only a logical function division, and actual implementation can have another division manner, for example, multiple units / modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, devices or units / modules, which can be electrical, mechanical or other forms.

[0105] The units / modules described as separate components can or can not be physically separated, and the components displayed as units / modules can or can not be physical units / modules, that is, they can be located in one place, or can be distributed on multiple network units / modules. According to actual needs, some or all of the units / modules can be selected to achieve the purpose of the embodiment.

[0106] In addition, each functional unit / module in each embodiment of the present application can be integrated in one processing unit / module, or each unit / module can be physically present separately, or two or more units / modules can be integrated in one unit / module. The integrated unit / module can be realized in the form of hardware or in the form of a software functional unit / module.

[0107] When the integrated unit / module is realized in the form of a software functional unit / module and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the entire or part of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for executing all or part of the steps of the method described in each embodiment of the present application by a computer device (which can be a personal computer, a server, or a network device, etc.). The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (English full name: Read-Only Memory, English abbreviation: ROM), a random access memory (English full name: Random Access Memory, English abbreviation: RAM), a magnetic disk or an optical disk, and various program code storage media.

[0108] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calibrating a wedge angle of an optical wedge, the optical wedge being made of a single crystal material, the optical wedge comprising a first optical working surface, a second optical working surface, a top surface and a bottom surface, the top surface and the bottom surface being arranged in parallel, the first optical working surface and the second optical working surface being connected to opposite edges of the top surface and the bottom surface respectively, the first optical working surface being perpendicular to the top surface and being arranged non-parallel to the second optical working surface, characterized in that, The method comprises the following steps: S1, using a scanning electron microscope to respectively perform image scanning on the top surface and the bottom surface along an x-axis direction to obtain scanning images; the x-axis is perpendicular to the first optical working surface; S2, respectively extracting light intensity distribution diagrams of the scanning images of the top surface and the bottom surface in the x-axis direction, counting the number of pixel points corresponding to each period of the light intensity distribution diagrams of the top surface and the bottom surface, and counting the number of pixel points contained in the scanning images of the top surface and the bottom surface in the x-axis direction, and respectively calculating the size x1 of the top surface in the x-axis direction and the size x2 of the bottom surface in the x-axis direction according to the following formula: x1=N1·C1 / n1; x2=N2·C1 / n2; In the formula, C1 represents the lattice period size of the top surface or the bottom surface of the optical wedge; n1 and n2 respectively represent the number of pixel points corresponding to each period in the light intensity distribution diagram of the top surface and the bottom surface of the optical wedge, and N1 and N2 respectively represent the number of pixel points contained in the scanning images of the top surface and the bottom surface of the optical wedge in the x-axis direction; S3, obtaining the size h of the first optical working surface in the z-axis direction; the z-axis is perpendicular to the top surface; S4, calculating the wedge angle α of the optical wedge according to the following formula: α=arctan(|x2-x1| / h).

2. The optical wedge wedge angle calibration method of claim 1, wherein, The material of the optical wedge is monocrystalline silicon.

3. The optical wedge wedge angle calibration method of claim 2, wherein, The top surface and the bottom surface are parallel to the {111} crystal surface of monocrystalline silicon.

4. The method of claim 1, wherein, The size h of the first optical working surface in the z-axis direction is obtained by the following steps: S31, using a scanning electron microscope to perform image scanning on the first optical working surface along the z-axis direction to obtain a scanning image; S32, extract the light intensity distribution diagram of the scanning image of the first optical working surface in the z-axis direction, and count the number n of pixel points corresponding to each period of the light intensity distribution diagram of the first optical working surface h , and count the number N of pixel points contained in the scanning image of the first optical working surface in the z-axis direction h ; calculate the size h of the first optical working surface in the z-axis direction according to the following formula: h = N h • C2 / n h ; In the formula, C2 represents the lattice period size of the first optical working surface of the optical wedge.

5. The method of wedge angle calibration of claim 1, wherein, The size h of the first optical working surface in the z-axis direction is obtained by measurement with an optical profiler, an optical microscope, a laser interferometer, a laser scanning microscope or an atomic force microscope.

6. A wedge angle calibration device for calibrating a wedge angle of an optical wedge, the optical wedge being made of a single crystal material, the optical wedge comprising a first optical working surface, a second optical working surface, a top surface and a bottom surface, the top surface and the bottom surface being arranged in parallel, the first optical working surface and the second optical working surface being connected to opposite edges of the top surface and the bottom surface respectively, the first optical working surface being perpendicular to the top surface and being arranged non-parallel to the second optical working surface, characterized in that, The device comprises: a scanning electron microscope configured to perform image scanning on the surface of the optical wedge in a preset direction to obtain a scanning image; an image processing module configured to extract a light intensity distribution diagram of the scanning image in the preset direction; a pixel counting module for counting the number of pixel points corresponding to each period of the light intensity distribution diagram and counting the number of pixel points of the scanning image in the preset direction; a calculation module for calculating the size x1 of the top surface of the optical wedge in the x-axis direction and the size x2 of the bottom surface of the optical wedge in the x-axis direction according to the following formula: x1=N1·C1 / n1; x2=N2·C1 / n2; In the formula, C1 represents the lattice period size of the top surface or the bottom surface of the optical wedge; n1 and n2 respectively represent the number of pixel points corresponding to each period in the light intensity distribution diagram of the top surface and the bottom surface of the optical wedge, and N1 and N2 respectively represent the number of pixel points contained in the scanning images of the top surface and the bottom surface of the optical wedge in the x-axis direction; and calculating the wedge angle α of the optical wedge according to the following formula: α=arctan(|x2-x1| / h); In the formula, h represents the size of the first optical working surface of the optical wedge in the z-axis direction.

7. The wedge angle calibration device of claim 6, wherein, The calculation module calculates the size h of the first optical working surface in the z-axis direction according to the following formula: h = N h • C2 / n h ; In the formula, C2 represents the lattice period size of the first optical working surface of the optical wedge, n h is the number of pixel points corresponding to each period of the light intensity distribution map of the first optical working surface of the optical wedge, N h is the number of pixel points contained in the scanning image of the first optical working surface of the optical wedge in the z-axis direction.

8. The wedge angle calibration device of claim 6, wherein, The optical measurement module is further configured to measure a size h of the first optical working surface in a z-axis direction, and the optical measurement module comprises at least one of an optical profiler, an optical microscope, a laser scanning microscope, and an atomic force microscope.

9. The wedge angle calibration device of claim 6, wherein, The error analysis module is further configured to calculate a calibration error of the wedge angle of the optical wedge according to an error transfer function, and the error transfer function is: The error analysis module is further configured to calculate a calibration error of the wedge angle of the optical wedge according to an error transfer function, and the error transfer function is: ； wherein denotes the error value of the wedge angle a, denotes the error value of x1, denotes the error value of x2, denotes the error value of h.

10. A computer storage medium, characterized in that, The computer program is stored in the memory and is executed by the processor to implement the wedge angle calibration method of the optical wedge according to any one of claims 1-5.

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