CN116482123A - A method, system, equipment and medium for detecting microscopic defects on the surface of an optical element - Google Patents

Abstract

The invention is suitable for the technology of detecting the defects of a precision optical element, and provides a method, a system, equipment and a medium for detecting microscopic defects on the surface of the optical element. A method of optical element surface micro-defect detection, the optical element surface micro-defect detection method comprising: acquiring a spatial scattering parameter of the surface of the optical element; constructing a Jones matrix according to the space scattering parameters, and converting the Jones matrix into a Mueller matrix; judging whether the surface of the optical element has defects according to the Mueller matrix. The invention adopts the incident light as polarized light, describes the polarized light by using the Jones matrix, and then converts the Jones matrix into the Mueller matrix to show the scattering distribution and the polarization state of a scattering field, so that the detection and the inspection of the surface target of the optical element are more accurate, the detection precision can reach the nanometer level, the detection range is wider, and different types of defects can be distinguished.

Description

A method, system, equipment and medium for detecting microscopic defects on the surface of an optical element

technical field

The invention belongs to precision optical component defect detection technology, in particular to a method, system, equipment and medium for detecting microscopic defects on the surface of optical components.

Background technique

During the processing of precision optical components, such as grinding, polishing, etc., it is easy to cause defects such as "pitting" on the surface of the component, and at the same time, dirt particles are easy to attach to the optical components exposed to the air. For precision optical components, the size of the surface defects is usually on the order of nanometers. If the incident light hits the surface defects, it will cause strong diffraction and scattering effects, which will greatly reduce the transmission quality of the beam in the optical system. Therefore, the detection equipment and detection technology for the surface and sub-surface defects of optical components have become the focus of attention of optical defect detection personnel.

Existing optical component defect detection technologies mainly include scattering dark field imaging, laser confocal microscopy, adaptive filter imaging, etc. Most optical component defect detection technologies are at the micron level or above, and the detection accuracy of dark field imaging is low, making it difficult to distinguish dirt particles and pitting.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a method for detecting microscopic defects on the surface of an optical element, aiming at solving the problem of low detection accuracy of optical element defects.

The embodiment of the present invention is achieved in this way, a method for detecting microscopic defects on the surface of an optical element, the method for detecting microscopic defects on the surface of an optical element includes:

Obtain the spatial scattering parameters of the surface of the optical element;

constructing a Jones matrix according to the spatial scattering parameters, and converting the Jones matrix into a Muller matrix;

According to the Mueller matrix, it is judged whether there is a defect on the surface of the optical element.

Another object of the embodiments of the present invention is a system for detecting microscopic defects on the surface of optical elements, the system for detecting microscopic defects on the surface of optical elements includes:

A light source modulation module, configured to output incident light;

a platform for setting the optical elements;

The detection module is used to detect the scattered light of the optical element;

The computer equipment is used for controlling the movement of the platform, obtaining parameters of incident light and scattered light, and judging whether there is a defect on the surface of the optical element.

Another object of the embodiments of the present invention is a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the method for detecting microscopic defects on the surface of an optical element.

Another object of the embodiments of the present invention is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the processor executes the steps of the method for detecting microscopic defects on the surface of an optical element.

The embodiment of the present invention provides a method for detecting microscopic defects on the surface of an optical element. The incident light is polarized light. The Jones matrix is used to describe the polarized light, and the scattering distribution and polarization state of the scattering field can be represented by converting the Jones matrix into a Mueller matrix. pBRDF can not only completely describe the light scattering distribution on the surface of the element, but also characterize the light scattering polarization characteristics of the target.

Description of drawings

FIG. 1 is an application environment diagram of the method for detecting microscopic defects on the surface of an optical element provided by an embodiment of the present invention;

FIG. 2 is a structural diagram of a microscopic defect detection system on the surface of an optical element provided by an embodiment of the present invention;

3 is a flowchart of a method for detecting microscopic defects on the surface of an optical element provided by an embodiment of the present invention;

Fig. 4 is the schematic diagram of pBRDF geometry provided by the embodiment of the present invention;

Fig. 5 is the reflection Mueller matrix spectrum when the optical element provided by the embodiment of the present invention has "pockmarks" or not;

Fig. 6 is the reflection Mueller matrix spectrum of the "pitting" and "dirty particles" on the surface of the optical element provided by the embodiment of the present invention;

Fig. 7 is a structural block diagram of an optical element surface microscopic defect detection system provided by an embodiment of the present invention;

Fig. 8 is a block diagram of the internal structure of a computer device in one embodiment.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

It can be understood that the terms "first", "second" and the like used in the present application may be used to describe various elements herein, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first xx script could be termed a second xx script, and, similarly, a second xx script could be termed a first xx script, without departing from the scope of the present application.

FIG. 1 is an application environment diagram of the method for detecting microscopic defects on the surface of an optical element provided by an embodiment of the present invention. As shown in FIG. 1 , the application environment includes a light source modulation module 100, a detection module 200, a platform 7, and a computer device 12.

The light source modulation module 100 is used to output the incident polarized light beam, the optical element to be tested is arranged on the platform 7, and the detection module 200 is used to detect the scattered light in the scattered field.

As shown in FIG. 2 , the light source modulation module 100 includes a xenon lamp light source 1, a beam shaping unit 2, a first polarizer 3, a first 1/4 wave plate 4, a second polarizer 5, and a second 1/4 wave plate 6 arranged in sequence; wherein the first polarizer 3 and the first 1/4 wave plate 4 form a circular polarization generator; the second polarizer 5 and the second 1/4 wave plate 6 form a polarizing system. The detection module 200 includes a photoelastic modulator 8, a third 1/4 wave plate 9, a third polarizer 10 and a CCD detector 11 arranged in sequence; wherein, the third 1/4 wave plate 9 and the third polarizer 10 constitute an analysis system. The computer equipment 12 is connected with the platform 7 and the CCD detector 11 respectively.

The computer device 12 is used to acquire data, process data and output data, and may be a smart phone, a tablet computer, a notebook computer, a desktop computer, a smart watch, etc., but is not limited thereto. The detection module 200, the platform 7 and the computer device 12 can be connected through a network, which is not limited in the present invention.

As shown in FIG. 3 , in one embodiment, a method for detecting microscopic defects on the surface of an optical element is proposed. This embodiment is mainly illustrated by using the method applied to the computer device 12 in FIG. 1 . A method for detecting microscopic defects on the surface of an optical element may specifically include the following steps:

Step S102, acquiring spatial scattering parameters of the surface of the optical element.

In this embodiment, as shown in Figure 4, the spatial scattering parameters include the refractive index n of the optical element, the incident angle , scattering angle , azimuth etc. The surface defects of precision optical components are on the order of nanometers in size, which will cause strong diffraction and scattering effects when irradiated by light. Generally speaking, the defects of precision optical components are pits or dirt particles, and the frequencies of the two are similar. As shown in Figure 4, the wavelength is of light waves, at an angle of incidence , azimuth Backward Scattering Angle , azimuth The physical process of direction emission.

Step S104, constructing a Jones matrix according to the spatial scattering parameters, and converting the Jones matrix into a Muller matrix.

In this embodiment, since the incident light used in this method is polarized light, and the polarized light can be described by Jones matrix, the scattering distribution and polarization state of the scattering field can be represented by converting the Jones matrix into a Mueller matrix. Bidirectional Reflectance Distribution Function (BRDF, Bidirectional Reflectance Distribution Function) is a commonly used function for modeling research on the surface scattering characteristics of optical components, defined as the ratio of the radiance emitted by the target surface to the irradiance incident on the target surface. However, this embodiment adopts pBRDF on the basis of BRDF, that is, polarized bidirectional reflectance distribution function (polarized Bidirectional Reflectance Distribution Function). The polarized bidirectional reflectance distribution function (pBRDF) is obtained by extending it to the polarization case through the Mueller matrix on the basis of the BRDF. BRDF ignores the spatial scattering distribution on the surface of the optical element in the calculation. In contrast, pBRDF can not only completely describe the light scattering distribution on the surface of the element, but also characterize the light scattering polarization characteristics of the target. The detection and inspection of the target on the surface of the optical element is more accurate, and the detection accuracy can reach the nanometer level.

Step S106, judging whether there is a defect on the surface of the optical element according to the Mueller matrix.

In this embodiment, the Mueller matrix can be visually represented in the form of an image. As shown in Figure 5, the horizontal axis represents the wavelength, and the vertical axis represents the value of the Mueller matrix elements. The solid line represents the reflection Mueller matrix spectral curve of the pit detection, and the dotted line represents the reflection Mueller matrix spectral curve of the surface of the defect-free precision optical element. By comparing each other, it can be seen from Figure 4 that the Mueller matrix elements , and It can clearly distinguish whether there are pitted areas on the surface of the optical element. Therefore, the method for judging surface defects in this embodiment is more intuitive, and can accurately detect whether there are pits in the optical element.

In one embodiment, step S104 may specifically include steps S202~S206:

Step S202, constructing the first Jones matrix about the scattering field according to the spatial scattering parameters in, Represents the Jones matrix; Indicates the refractive index of the optical element; Indicates the incident angle of the incident surface; Indicates the scattering angle of the scattering surface; Indicates the azimuth.

Step S204, obtain the elements of the Muller matrix according to the first Jones matrix in, Indicates the elements of the Muller matrix, i,j=1,2,3,…;

Step S206, according to the Rayleigh-Rice theoretical model, use the polarized bidirectional reflectance distribution function to find the first Mueller matrix ;in, Represents a polarized bidirectional reflectance distribution function, that is, the first Mueller matrix; Indicates the wavelength; Represents the power spectral density function.

In this embodiment, the Jones matrix is used to describe the pits on the surface of the precision optical element. Digging refers to pits and defects on the surface of optical components. For tiny-sized pitting defects, the depth is often between tens of nanometers and hundreds of nanometers, which can be well described by Rayleigh-Rice theory. Combining the definition of pBRDF and the calculation method of grating diffraction intensity, the pBRDF calculation formula of the Rayleigh-Rice theoretical model of pitting is obtained, and finally the first Mueller matrix is obtained. The first Mueller matrix is output in the form of reflected Mueller spectrum, as shown by the solid line in Figure 4.

In one embodiment, step S106 may specifically include steps S302~S304:

Step S302, obtaining the spatial scattering parameters of the defect-free area on the surface of the optical element, constructing the second Jones matrix, and obtaining the second Mueller matrix according to the Rayleigh-Rice theoretical model.

Step S304, acquiring the first Mueller matrix, comparing the first Mueller matrix with the second Mueller matrix, and judging whether there is a defect on the surface of the optical element.

In this embodiment, it is necessary to obtain the second Mueller matrix of the defect-free area on the surface of the optical element first, and use the microscopic defect detection device to draw the wavelength The reflection Mueller matrix spectrum of the optical element in the defect-free region in the range of 300nm~700nm, as shown in the dotted curve in Figure 5. Next, the movement of the platform 7 is controlled by the computer device 12, so that the pits are exposed to the light source, the first Mueller matrix is calculated, and the reflection Mueller matrix spectrum of the pits is drawn, as shown in the solid line curve in FIG. 5 . Through the difference analysis of two different curves, it is judged whether there are defects on the surface of the optical element. If the curve difference is large, it means that there are pits on the surface of the optical element. If the curve difference is small, there is no defect on the surface of the optical element.

In one embodiment, after step S106, the type of the defect is judged, and the type of the defect is judged including steps S402 to S406:

Step S402, using the spatial scattering parameters to construct the third Jones matrix matrix of the scattering field in, Indicates the phase delay factor due to the incident field: ; is the phase delay factor of the scattered field: ; d is the distance from the defect particle center to the surface of the optical element; is the Fresnel reflection coefficient of s-polarized light; is the Fresnel reflection coefficient of p-polarized light.

Step S404, using the third Jones matrix to obtain the elements of the Mueller matrix, and according to the Rayleigh-Rice scattering theory model, using the polarization bidirectional reflectance distribution function to obtain the third Mueller matrix matrix ;in, represents the third Mueller matrix; Indicates the wavelength; Indicates the refractive index of the dirt particle. Step S406, comparing the first Mueller matrix with the third Mueller matrix, and judging that the defects are pitting or dirty particles.

In this embodiment, since the surface dirt particles and pockmarks appear as bright spots in the dark background on the dark field image, it is difficult to distinguish these two kinds of defects by the conventional dark field imaging method. The depth of pitting is between tens of nanometers and hundreds of nanometers, which can be well described by Rayleigh-Rice theory. However, for dirty particles above the surface, the equivalent diameter is generally between tens of nanometers and tens of microns, and the Rayleigh-Rice scattering theory of particles in free space can well explain the scattering characteristics of dirty particles.

The first Mueller matrix represents the scattering characteristics of pitting, while the third Mueller matrix represents the scattering characteristics of dirty particles. Comparing the reflection Mueller matrix spectrum of pitting and the reflection Mueller matrix spectrum of dirty particles can clearly distinguish pitting from dirty particles. Before comparing the reflection Mueller matrix spectrum of pitting with that of dirty particles, it is necessary to predetermine the relationship between the reflection Mueller matrix spectrum of general pitting on the optical surface and the reflection Mueller matrix spectrum of a non-defective surface, so as to obtain the reflection Mueller matrix spectrum of pitting. When it is necessary to detect a defect, the Rayleigh-Rice scattering theory is used to obtain the reflection Mueller matrix spectrum of the dirty particle, and it can be judged whether the defect is a dirty particle by comparing the reflection Mueller matrix spectrum of the general pit.

As shown in Figure 6, pockmarks are dashed lines, dirt particles are solid lines, Mueller matrix elements , and Dirt particles and pits on the surface of optical components can be clearly distinguished. Obviously, based on the different physical properties of dirt particles and pits, the polarization state modulation of light is different, and the emission Mueller matrix spectrum proposed in this embodiment can effectively distinguish these two types of defects.

As shown in Figure 1, in one embodiment, a system for detecting microscopic defects on the surface of an optical element is provided, and the system for detecting microscopic defects on the surface of an optical element includes:

A light source modulation module 100, configured to output incident light;

Platform 7 for setting optical elements;

A detection module 200, configured to detect the scattered light of the optical element;

The computer equipment 12 is used to control the movement of the platform 7, acquire the parameters of incident light and scattered light, and determine whether there is a defect on the surface of the optical element 13.

In this embodiment, the light source modulation module 100 includes a xenon lamp light source 1, a beam shaping unit 2, a first polarizer 3, a first 1/4 wave plate 4, a second polarizer 5, and a second 1/4 wave plate 6 arranged in sequence; wherein the first polarizer 3 and the first 1/4 wave plate 4 form a circular polarization generator; the second polarizer 5 and the second 1/4 wave plate 6 form a polarizing system. The detection module 200 includes a photoelastic modulator 8, a third 1/4 wave plate 9, a third polarizer 10 and a CCD detector 11 arranged in sequence; wherein, the third 1/4 wave plate 9 and the third polarizer 10 constitute an analysis system. The computer equipment 12 is connected with the platform 7 and the CCD detector 11 respectively. The specific working principle is as follows:

The optical element 13 to be tested is placed on the two-dimensional mobile platform 7, and the xenon lamp light source 1 emits laser light to homogenize and expand the initial Gaussian beam through the beam shaping unit 2 to remove the high-frequency stray light; then pass through the circular polarization system formed by the first polarizer 3 and the first 1/4 wave plate 4 to ensure that the light wave energy of the beam entering the polarization system is the same in all directions; The light passes through the photoelastic modulator 8; the intensity of the emitted light after the third 1/4 wave plate 9 and the third polarizer 10 is received by the CCD detector 11; finally, the computer device 12 analyzes the received light intensity, and inversely obtains the Mueller matrix of the optical element to be tested.

In this embodiment, the conventional detection system uses a double-rotating compensator-type ellipsometer to characterize various samples. It is necessary to precisely control the rotation accuracy of the two rotating compensators, which is prone to errors. However, in this embodiment, only one photoelastic modulator 8 is used to build a photoelastic modulation type ellipsometer, and the structure is relatively simple.

As shown in Figure 7, in one embodiment, the computer device 12 includes:

A data acquisition unit 300, configured to acquire spatial scattering parameters on the surface of the optical element 13;

A matrix conversion unit 400, configured to construct a Jones matrix according to the spatial scattering parameters, and convert the Jones matrix into a Muller matrix;

The judging unit 500 is configured to judge whether there is a defect on the surface of the optical element 13 according to the Mueller matrix.

Figure 8 shows a diagram of the internal structure of a computer device in one embodiment. Specifically, the computer device may be the computer device 12 in FIG. 1 . As shown in FIG. 8 , the computer equipment includes a processor, a memory, a network interface, and an input device connected through a system bus. Wherein, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and also stores a computer program. When the computer program is executed by the processor, the processor can realize the method for detecting microscopic defects on the surface of the optical element. A computer program may also be stored in the internal memory, and when the computer program is executed by the processor, the processor may execute the method for detecting microscopic defects on the surface of the optical element. The display screen of the computer equipment may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment may be a touch layer covered on the display screen, or a button, a trackball or a touch pad provided on the casing of the computer equipment, or an external keyboard, touch pad or mouse, etc.

Those skilled in the art can understand that the structure shown in FIG. 8 is only a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer equipment to which the solution of the application is applied. The specific computer equipment may include more or less components than those shown in the figure, or combine certain components, or have different component arrangements.

In one embodiment, a computer device is proposed, the computer device includes a memory, a processor, and a computer program stored on the memory and operable on the processor, and the processor implements the following steps when executing the computer program:

Obtain the spatial scattering parameters of the surface of the optical element;

constructing a Jones matrix according to the spatial scattering parameters, and converting the Jones matrix into a Muller matrix;

According to the Mueller matrix, it is judged whether there is a defect on the surface of the optical element.

In one embodiment, a computer-readable storage medium is provided. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the processor is made to perform the following steps:

Obtain the spatial scattering parameters of the surface of the optical element;

constructing a Jones matrix according to the spatial scattering parameters, and converting the Jones matrix into a Muller matrix;

According to the Mueller matrix, it is judged whether there is a defect on the surface of the optical element.

It should be understood that although the various steps in the flow charts of the embodiments of the present invention are shown sequentially according to the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in each embodiment may include a plurality of sub-steps or multiple stages, these sub-steps or stages are not necessarily executed at the same time, but may be executed at different times, and the execution order of these sub-steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least a part of other steps or sub-steps or stages of other steps.

Those of ordinary skill in the art can understand that realizing all or part of the processes in the methods of the above embodiments can be completed by instructing related hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Wherein, any references to memory, storage, database or other media used in the various embodiments provided in the present application may include non-volatile and/or volatile memory. Nonvolatile memory can include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), Memory Bus (Rambus) Direct RAM (RDRAM), Direct Memory Bus Dynamic RAM (DRDRAM), and Memory Bus Dynamic RAM (RDRAM), among others.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A method for detecting microscopic defects on the surface of an optical element, which is characterized by comprising the following steps:

acquiring a spatial scattering parameter of the surface of the optical element;

constructing a Jones matrix according to the space scattering parameters, and converting the Jones matrix into a Mueller matrix;

judging whether the surface of the optical element has defects according to the Mueller matrix;

the method for constructing the Jones matrix according to the space scattering parameters and converting the Jones matrix into a Mueller matrix comprises the following steps:

constructing a first Jones matrix for a scattered field based on spatial scattering parameters

The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>Representing a jones matrix; />Representing the refractive index of the optical element; />Representing the angle of incidence of the incident face; />Indicating the scattering angle of the scattering surface; />Representing azimuth angles;

obtaining array elements of a Mueller matrix according to the first Jones matrix

Wherein,,matrix elements representing a muller matrix, i, j=1, 2,3, …;

according to Rayleigh-Rice theory model, using polarized bidirectional reflection distribution function to obtain first Mueller matrix of optical element surfaceThe method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>Representing a polarized bidirectional reflectance distribution function, namely the first mueller matrix; />Representing wavelength; />Representing a power spectral density function.

2. The method for detecting microscopic defects on a surface of an optical element according to claim 1, wherein the step of determining whether the surface of the optical element is defective according to the muller matrix comprises the steps of:

acquiring space scattering parameters of a defect-free area on the surface of the optical element, constructing a second Jones matrix, and obtaining a second Mueller matrix according to a Rayleigh-Rice theoretical model;

and acquiring the first Mueller matrix, comparing the first Mueller matrix with the second Mueller matrix, and judging whether the surface of the optical element has defects or not.

3. The method for detecting microscopic defects on a surface of an optical element according to claim 2, wherein the step of determining whether the surface of the optical element has defects according to the muller matrix, and then determining the type of the defects comprises the steps of:

construction of third Jones matrix of scattered field by using spatial scattering parametersWherein (1)>Representing the phase delay factor produced by the incident field: />；/>As a fringe field phase delay factor: />The method comprises the steps of carrying out a first treatment on the surface of the d is the distance from the center of the defect particle to the surface of the optical element; />Fresnel reflection for s-polarized lightA radial coefficient; />Fresnel reflection coefficient for p-polarized light; obtaining array elements of a Mueller matrix by using the third Jones matrix, and obtaining a third Mueller matrix by using a polarized bidirectional reflection distribution function according to a Rayleigh-Rice scattering theoretical model>The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>Representing the third muller matrix; />Representing wavelength; />Indicating the refractive index of the smudge particles; comparing the first and third Mueller matrices, and judging that the defect is a pit or a dirt particle.

4. An optical element surface micro defect detection system, characterized by performing the steps of the optical element surface micro defect detection method according to any one of claims 1 to 3, the optical element surface micro defect detection system comprising:

the light source modulation module is used for outputting incident light;

a stage for setting an optical element;

a detection module for detecting scattered light of the optical element;

the computer equipment is used for controlling the platform to move, acquiring parameters of incident light and scattered light and judging whether the surface of the optical element has defects or not;

the computer device includes:

a data acquisition unit for acquiring a spatial scattering parameter of the surface of the optical element;

the matrix conversion unit is used for constructing a Jones matrix according to the space scattering parameters and converting the Jones matrix into a Mueller matrix;

and the judging unit is used for judging whether the surface of the optical element has defects according to the Mueller matrix.

5. A computer device comprising a memory and a processor, the memory having stored therein a computer program which, when executed by the processor, causes the processor to perform the steps of the optical element surface micro defect detection method according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored thereon a computer program which, when executed by a processor, causes the processor to perform the steps of the optical element surface micro defect detection method according to any one of claims 1 to 3.