Device and method for measuring grating defects

Abstract

The present invention discloses a method and a device for measuring grating defects, relating to the technical field of optical measurement and imaging. It is used to solve the problem that the existing grating defect detection cannot measure three-dimensional dimensions. It includes: obtaining a focused light intensity map and an over-focused light intensity map including three-dimensional information of a grating to be measured based on the device for measuring grating defects; obtaining axial intensity derivatives of the focused light intensity map and the over-focused light intensity map according to the finite difference of the intensity image; obtaining the phase distribution of the grating to be measured according to the Fourier transform property and the axial intensity derivative; based on the modulation characteristic of surface defects on the phase, converting the phase distribution of the grating to be measured into surface defect depth distribution information of the grating to be measured.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement and imaging technologies, and more particularly to a method and device for measuring grating defects. Background Art

[0002] A grating is an optical element composed of a large number of equally spaced and equally wide parallel slits. A commonly used grating element is to engrave many equally spaced and equally wide parallel scratches on a glass sheet, which is widely used in spectral analysis, measuring the components of each spectral line of a luminescent substance, analyzing the structure of substances, etc. During the manufacturing process of a grating sheet, due to the interference of external factors, some local defects may occur, and these defects may affect the performance of the grating.

[0003] Currently, at home and abroad, the surface defects of gratings are mainly inspected manually through a high-power microscope. This method not only has low detection efficiency and high labor costs, but also the detection effect is directly affected by human errors. Existing machine vision-based grating defect detection methods perform a series of processing techniques such as preprocessing, enhancement, redrawing, and feature recognition on the obtained images, but there are still limitations. They can only obtain the two-dimensional size of the defects and cannot measure their depth information. Summary of the Invention

[0004] Embodiments of the present invention provide a device and method for measuring grating defects, which are used to solve the problem that existing grating defect detection cannot measure three-dimensional dimensions.

[0005] Embodiments of the present invention provide a device for measuring grating defects, including: a first polarizer, a second polarizer, a first beam splitter, a second beam splitting prism, a third beam splitting prism, a first CCD, and a second CCD;

[0006] The first polarizer is disposed between the light source and the first beam splitter;

[0007] The second polarizer is disposed on the light output side of the refracted light of the first beam splitter, and the second polarizer is orthogonally disposed with the first polarizer;

[0008] The second beam splitting prism is disposed above the grating to be measured, and is used for transmitting and reflecting the first reflected light from the grating to be measured to form a first transmitted light and a second reflected light;

[0009] The third beam splitting prism is disposed on the light output side of the transmitted light of the second beam splitting prism, and a 4f system is disposed between the third beam splitting prism and the second beam splitting prism. The first transmitted light passes through the 4f system and the third beam splitting prism to form a second transmitted light and a third reflected light; the second transmitted light enters the first CCD located at the focal point of the second lens included in the 4f system, and the third reflected light enters the second CCD located behind the focal point of the second lens included in the 4f system.

[0010] Preferably, it further includes a light intensity detector;

[0011] The second reflected light is reflected by the first beam splitter prism to form a fourth reflected light, and the fourth reflected light passes through the second polarizer and the converging lens and enters the light intensity detector.

[0012] Preferably, it further includes a first light trap and a second light trap;

[0013] The first light trap is located above the second polarizer. After the second reflected light is reflected by the first beam splitter prism, part of the light enters the first light trap;

[0014] The second light trap is located between the first lens and the second lens included in the 4f system and on one side of the focal point of the first lens;

[0015] After the first transmitted light passes through the first lens, part of the light enters the second light trap.

[0016] Preferably, it further includes an expanding and collimating module;

[0017] The expanding and collimating module is located between the light source and the first polarizer, and the expanding and collimating module includes a diaphragm and a collimating lens.

[0018] An embodiment of the present invention provides a method for measuring grating defects, including:

[0019] Obtaining a focused light intensity map and an over-focused light intensity map including three-dimensional information of a grating to be measured based on a device for measuring grating defects;

[0020] Obtaining axial intensity derivatives of the focused light intensity map and the over-focused light intensity map according to finite differences of intensity images; obtaining a phase distribution of the grating to be measured according to Fourier transform properties and the axial intensity derivatives;

[0021] Based on the modulation characteristic of surface defects on the phase, the phase distribution of the grating to be measured can be converted into surface defect depth distribution information of the grating to be measured.

[0022] Preferably, the axial intensity derivative is as follows:

[0023]

[0024] Before obtaining the phase distribution of the grating to be measured according to Fourier transform properties and the axial intensity derivatives, it further includes:

[0025] Solving the following light intensity transport equation according to the axial intensity derivative:

[0026]

[0027] Among them, I 0 (x) represents the focused light intensity pattern, and I z (x) represents the defocused light intensity pattern, x represents the lateral coordinate on the plane perpendicular to the optical axis, corresponding to the two-dimensional spatial vector (x, y), and z represents the spacing between the defocused light intensity pattern I z (x) and the focused light intensity pattern I 0 (x) in the direction of the optical axis, represents the phase of the grating to be measured, represents the gradient operator, k represents the wave number k = 2π / λ, λ is the wavelength of the light source, and ψ represents the auxiliary function, represents the axial intensity derivative.

[0028] Preferably, obtaining the phase distribution of the grating to be measured according to the Fourier transform property and the axial intensity derivative specifically includes:

[0029] Obtaining the expression of the auxiliary function according to the Fourier transform property and the axial intensity derivative:

[0030]

[0031] The phase distribution of the grating to be measured is obtained based on the Fourier property of the auxiliary function:

[0032]

[0033] Among them, q x represents the variable corresponding to x in the Fourier space, and q y represents the variable corresponding to y in the Fourier space, F represents the Fourier transform, and F -1 represents the inverse Fourier transform, is the inverse Laplace operator, ψ represents the auxiliary function, represents the axial intensity derivative.

[0034] Preferably, the surface defect depth distribution information of the grating to be measured is as follows:

[0035]

[0036] Among them, h(x, y) represents the surface defect depth distribution information of the grating to be measured, represents the phase of the grating to be measured, and λ is the wavelength of the light source.

[0037] An embodiment of the present invention provides a computer device, which includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the method for measuring the grating defect described in any one of the above.

[0038] An embodiment of the present invention provides a computer-readable storage medium storing a computer program, which when executed by a processor causes the processor to execute the method for measuring grating defects described in any one of the above.

[0039] An embodiment of the present invention provides a device and method for measuring grating defects. The method includes: obtaining a focused intensity map and an overfocus intensity map including three-dimensional information of a grating to be measured based on a measuring device for grating defects; obtaining axial intensity derivatives of the focused intensity map and the overfocus intensity map according to finite differences of intensity images; obtaining a phase distribution of the grating to be measured according to Fourier transform properties and the axial intensity derivatives; and converting the phase distribution of the grating to be measured into surface defect depth distribution information of the grating to be measured based on the modulation characteristic of surface defects on the phase. This method first obtains a focused intensity map and an overfocus intensity map based on a measuring device for grating defects. Among them, the measuring device for grating defects includes a 4f system, and two CCDs included in the 4f system respectively record the focused intensity map and the overfocus intensity map, which has the characteristics of good real-time performance and high algorithm accuracy. At the same time, during the test process, when the test parameters are determined, the detection process does not require movement or secondary adjustment, and the grating defect measurement process is less affected by temperature and external environment interference. Therefore, very stable and high-precision detection results can be obtained. Furthermore, compared with traditional interference-based phase measurement methods, the intensity transport equation has many unique advantages such as non-interference, simple calculation, no need for phase unwrapping, no need for a complex optical system, and a harsh experimental environment. At the same time, a significant feature different from the iterative phase retrieval algorithm is that the intensity transport equation does not rely on traditional diffraction calculation formulas for iterative phase retrieval, but directly obtains phase information by numerically solving the intensity transport equation without any iterative solution process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0041] Figure 1 It is a schematic structural diagram of a 4F system provided by the prior art;

[0042] Figure 2 It is a schematic diagram of a device for measuring grating defects provided by an embodiment of the present invention;

[0043] Figure 3 It is a schematic flowchart of a method for measuring grating defects provided by an embodiment of the present invention;

[0044] Among them, there are a laser light source 1, a beam expander and collimator module 2, a first polarizer 3, a first beam splitter prism 4, a second polarizer 5, a converging lens 6, a first light trap 7, a light intensity detector 8, a grating under test 9, a second beam splitter prism 10, a first lens 11, a second light trap 12, a second lens 13, a third beam splitter prism 14, a first CCD 15, and a second CCD 16. Specific implementation manner

[0045] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] Technical terms involved in the patent:

[0047] 1. The optical 4f system is composed of an object plane, a Fourier lens L 1 , a Fourier lens L 2 and an image plane, as Figure 1 shown. Among them, the distance between the front Fourier lens and the rear Fourier lens is 2f, the distance between the object plane and the front Fourier lens is f, and the distance between the rear Fourier lens and the image plane is f.

[0048] 2. The transport of intensity equation (TIE) is a second-order elliptic partial differential equation, which clarifies the quantitative relationship between the change in light intensity along the optical axis direction and the phase of the light wave on the plane perpendicular to the optical axis. By solving the transport of intensity equation, it is only necessary to measure the light intensity distribution of the light wave field under test at different transmission distances to quantitatively restore the phase information, and there is no need to rely on interference or additional reference light.

[0049] Figure 2 It is a schematic structural diagram of a device for measuring grating defects provided by an embodiment of the present invention; as Figure 2 shown, the device for measuring grating defects mainly includes: a first polarizer 3, a second polarizer 5, a first beam splitter prism 4, a second beam splitter prism 10, a third beam splitter prism 14, a first CCD 15, and a second CCD 16.

[0050] Specifically, in this embodiment, the first polarizer 3 is arranged between the laser light source 1 system and the first beam splitter prism 4. Correspondingly, the second polarizer 5 is arranged on the light output side of the refracted light of the first beam splitter prism 4. Therefore, the first polarizer 3 and the second polarizer 5 are arranged orthogonally.

[0051] Further, the device includes a second beam splitting prism 10, which is disposed above the grating 9 to be measured. On the one hand, it reflects the transmitted light passing through the first beam splitting prism 4, so that the reflected light passing through the second beam splitting prism 10 is reflected by the grating 9 to be measured to form a first reflected light. On the other hand, it transmits and reflects the first reflected light reflected by the grating 9 to be measured to respectively form a second reflected light and a first transmitted light.

[0052] In this embodiment, the first lens 11 and the second lens 13 included in the 4f system are disposed between the second beam splitting prism 10 and the third beam splitting prism 14. After the first transmitted light from the second beam splitting prism 10 passes through the first lens 11, the second lens 13 and the third beam splitting prism 14, a second transmitted light and a third reflected light are formed.

[0053] Specifically, the second transmitted light enters the first CCD 15, where the first CCD 15 is disposed at the focal point of the second lens 13. Correspondingly, the third reflected light enters the second CCD 16, and the second CCD 16 is not disposed at the focal point of the second lens 13. It is disposed behind the focal point of the second lens 13. Both the first CCD 15 and the second CCD 16 are electrically connected to the processor. Finally, the focused light intensity map collected by the first CCD 15 and the over-focused light intensity map collected by the second CCD 16 are used to reconstruct the phase of the object through the phase recovery technology of the light intensity transmission equation, realizing the three-dimensional information measurement of the grating defect.

[0054] The device for measuring grating defects provided by the embodiment of the present invention includes a 4f system. The first CCD and the second CCD corresponding to the 4f system respectively record the focused light intensity map and the over-focused light intensity map, which have the characteristics of good real-time performance and high algorithm accuracy. At the same time, during the process of measuring grating defects, when the test parameters are determined, there is no need to move or make secondary adjustments during the test process, and the grating defect measurement process is less affected by temperature and external environment interference. Therefore, very stable and high-precision detection results can be obtained.

[0055] Exemplarily, the device for measuring grating defects further includes a light intensity detector 8, and the light intensity detector 8 is located on the light output side of the refracted light of the first beam splitting prism 4 and on the side of the second polarizer 5 away from the first beam splitting prism 4.

[0056] In the above embodiment, the second reflected light formed after the first reflected light passes through the second beam splitting prism 10 enters the first beam splitting prism 4 and is reflected by the first beam splitting prism 4 to form a fourth reflected light. The fourth reflected light passes through the second polarizer 5 and the converging lens 6 and then enters the light intensity detector 8. The light intensity detector 8 is electrically connected to the processor. The change of light intensity can be tested through the light detector to determine whether there are defects in the grating 9 to be measured.

[0057] Exemplarily, the device for measuring grating defects further includes a first light trap 7 and a second light trap 12. Among them, the first light trap 7 is located between the second polarizer 5 and the light intensity detector 8. In the embodiment of the present invention, the first light trap 7 is for receiving a part of the fourth reflected light reflected by the first beam splitter prism 4, that is, a part of the fourth reflected light formed after the second reflected light is reflected by the first beam splitter prism 4 will enter the first light trap 7. Therefore, the first light trap 7 is located above the second polarizer 5, not directly above the second polarizer 5.

[0058] The second light trap 12 is arranged between the first lens 11 and the second lens 13 included in the 4f system and is located on one side of the focal point of the first lens 11. After the first transmitted light passes through the first lens 11, part of the light will enter the second light trap 12.

[0059] In the embodiment of the present invention, the functions of the first light trap 7 and the second light trap 12 are both to absorb the diffracted light generated on the surface of the grating to be measured, so as to ensure that the information transmitted in the optical path mainly comes from the scattered light generated by the defects, and to realize the accurate detection of surface defects. The first light trap 7 is placed near the light intensity detector 8 to absorb the stray light in the detection path beam. The light intensity detector 8 measures the change in light intensity to determine whether there are defects in the detection part. If there are defects, the first CCD 15 is used to obtain the focused light intensity image, and the second CCD 16 is used to obtain the over-focused light intensity image. Finally, the collected images are reconstructed into the phase of the object through the phase recovery technology of the light intensity transmission equation to realize the three-dimensional information measurement of the grating defects.

[0060] Exemplarily, the device for measuring grating defects further includes an expanding and collimating module 2. The expanding and collimating module 2 is located between the laser light source 1 and the first polarizer 3. The expanding and collimating module 2 includes a diaphragm and a collimating lens.

[0061] Figure 3 is a schematic flowchart of a method for measuring grating defects provided by an embodiment of the present invention; the following will be combined with Figure 2 and Figure 3 introduce the method for measuring grating defects provided by an embodiment of the present invention. As Figure 2 shown, the method includes the following steps:

[0062] Step 101, obtaining a focused light intensity map and an over-focused light intensity map including the three-dimensional information of the grating to be measured based on the device for measuring grating defects;

[0063] Step 102, obtaining the axial intensity derivative of the focused light intensity map and the over-focused light intensity map according to the finite difference of the intensity image; obtaining the phase distribution of the grating to be measured according to the Fourier transform property and the axial intensity derivative;

[0064] Step 103: Based on the modulation characteristic of the surface defect on the phase, convert the phase distribution of the grating to be measured into the surface defect depth distribution information of the grating to be measured.

[0065] Before introducing the method for measuring grating defects provided by the embodiments of the present invention, first, in combination with Figure 2 introduce the device adopted by the method for measuring grating defects provided by the embodiments of the present invention, as Figure 2 shown.

[0066] In step 102, according to the finite difference of the intensity image, obtain the axial intensity derivative of the focused light intensity map and the over-focused light intensity map. The axial intensity derivative is as follows:

[0067]

[0068] where, I 0 (x) represents the focused light intensity map, I z (x) represents the over-focused light intensity map, x represents the transverse coordinate on the plane perpendicular to the optical axis, corresponding to the two-dimensional spatial vector (x, y), and z represents the spacing between the over-focused light intensity map I z (x) and the focused light intensity map I 0 (x) in the optical axis direction.

[0069] Then, use the obtained axial intensity derivative to solve the optical intensity transport equation. The optical intensity transport equation is as follows:

[0070]

[0071] where, represents the phase of the grating to be measured, represents the gradient operator, k represents the wave number k = 2π / λ, and λ is the wavelength of the light source.

[0072] In the embodiments of the present invention, an auxiliary function ψ is introduced for solving, which can be simplified. That is, the optical intensity transport equation can be transformed into:

[0073]

[0074] Furthermore, according to the Fourier transform property and the axial intensity derivative, the expression of the auxiliary function can be obtained, which is as follows:

[0075]

[0076] Using the Fourier property again for the expression of the auxiliary function, the phase distribution of the grating to be measured can be obtained, which is as follows:

[0077]

[0078] It should be noted that after obtaining the phase distribution of the grating to be measured according to the Fourier property by the auxiliary function expression, it is necessary to use the fast Fourier transform method here to obtain the final expression of the grating to be measured.

[0079] Among them, q x represents the variable corresponding to x in the Fourier space, q y represents the variable corresponding to y in the Fourier space, F represents the Fourier transform, F -1 represents the inverse Fourier transform. is the inverse Laplace operator, ψ represents the auxiliary function, represents the axial intensity derivative.

[0080] In step 103, in practical applications, when there are defects on the grating surface, these defects will cause the phase of the light wave to change, and the change in the phase can be used to infer the depth distribution information of the defects on the grating surface. That is, according to the modulation characteristics of the surface defects on the phase, the phase distribution of the grating to be measured is converted into the depth distribution information of the surface defects of the grating to be measured. In the embodiment of the present invention, the depth distribution information of the surface defects of the grating to be measured is as follows:

[0081]

[0082] Among them, h(x, y) represents the depth distribution information of the surface defects of the grating to be measured, represents the phase of the grating to be measured, and λ is the wavelength of the light source.

[0083] An embodiment of the present invention provides a device and method for measuring grating defects. The method includes: obtaining a focused intensity map and an overfocus intensity map including three-dimensional information of a grating to be measured based on a device for measuring grating defects; obtaining axial intensity derivatives of the focused intensity map and the overfocus intensity map according to finite differences of intensity images; obtaining a phase distribution of the grating to be measured according to Fourier transform properties and the axial intensity derivatives; and converting the phase distribution of the grating to be measured into surface defect depth distribution information of the grating to be measured based on the modulation characteristic of surface defects on the phase. This method first obtains a focused intensity map and an overfocus intensity map based on a device for measuring grating defects. Among them, the device for measuring grating defects includes a 4f system, and two CCDs included in the 4f system respectively record the focused intensity map and the overfocus intensity map, which has the characteristics of good real-time performance and high algorithm accuracy. At the same time, during the test process, after determining the test parameters, the detection process does not need to move or be adjusted secondly, and the grating defect measurement process is less affected by temperature and external environment interference. Therefore, very stable and high-precision detection results can be obtained. Furthermore, compared with traditional interference-based phase measurement methods, the intensity transport equation has many unique advantages such as non-interference, simple calculation, no need for phase unwrapping, no need for a complex optical system and a harsh experimental environment. At the same time, a significant feature different from the iterative phase retrieval algorithm is that the intensity transport equation does not rely on traditional diffraction calculation formulas for iterative phase retrieval, but directly obtains phase information by numerically solving the intensity transport equation without any iterative solution process.

[0084] Another embodiment of the present invention further provides a computer device, which includes: a processor and a memory; the memory is used to store computer program code, and the computer program code includes computer instructions; when the processor executes the computer instructions, the electronic device executes each step of measuring grating defects in the method flow shown in the above method embodiment.

[0085] Another embodiment of the present invention further provides a computer-readable storage medium, in which computer instructions are stored. When the computer instructions run on a computer device, the computer device is enabled to execute each step of measuring grating defects in the method flow shown in the above method embodiment.

[0086] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0087] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A device for measuring grating defects, characterized in that: include: A first polarizing plate, a second polarizing plate, a first beam splitter prism, a second beam splitter prism, a third beam splitter prism, a first CCD and a second CCD; A first polarizer, which is disposed between the light source and the first beam splitter prism; A second polarizer, which is arranged on the light-emitting side of the refracted light of the first beam splitter prism, and the second polarizer is arranged orthogonally to the first polarizer; A second beam splitter prism is disposed above the grating to be measured and is used to transmit and reflect the first reflected light from the grating to be measured to form a first transmitted light and a second reflected light; A third beam splitter prism is arranged on the light-emitting side of the transmitted light of the second beam splitter prism, and a 4f system is arranged between the third beam splitter prism and the second beam splitter prism, wherein the first transmitted light passes through the 4f system and the third beam splitter prism to form a second transmitted light and a third reflected light; the second transmitted light enters a first CCD located at the focus of the second lens included in the 4f system, and the third reflected light enters a second CCD located behind the focus of the second lens included in the 4f system; wherein the 4f system includes a first lens and a second lens; Also included is a light intensity detector; The second reflected light is reflected by the first beam splitter prism to form fourth reflected light, and the fourth reflected light passes through the second polarizer and the converging lens and enters the light intensity detector.

2. The device according to claim 1, characterized in that Also included is a first light trap and a second light trap; The first light trap is located on the upper side of the second polarizer, and after the second reflected light is reflected by the first beam splitter prism, part of the light enters the first light trap; The second light trap is located between the first lens and the second lens included in the 4f system, and is located on one side of the focus of the first lens; After the first transmitted light passes through the first lens, part of the light enters the second light trap.

3. The device according to claim 1, characterized in that Also included is a beam expansion and collimation module; The beam expansion and collimation module is located between the light source and the first polarizer, and the beam expansion and collimation module includes an aperture and a collimation lens.

4. A method for measuring grating defects, characterized in that: include: When the light intensity detector included in the device for measuring grating defects according to any one of claims 1 to 3 determines that the grating to be measured has defects, a focused light intensity map and an over-focus light intensity map including three-dimensional information of the grating to be measured are obtained based on the device for measuring grating defects; Obtaining the axial intensity derivatives of the focused light intensity map and the over-focus light intensity map according to the finite difference of the intensity image; obtaining the phase distribution of the grating to be measured according to the Fourier transform property and the axial intensity derivative; Based on the modulation characteristics of the surface defects on the phase, the phase distribution of the grating to be measured is converted into the surface defect depth distribution information of the grating to be measured.

5. The method according to claim 4, characterized in that The axial strength derivative is given by: Before obtaining the phase distribution of the grating to be measured according to the Fourier transform property and the axial intensity derivative, the method further includes: The light intensity transmission equation shown below is solved based on the axial intensity derivative: Among them, I0(x) represents the focused light intensity map, I z (x) represents the overfocus light intensity map, x represents the horizontal coordinate on the plane perpendicular to the optical axis, corresponding to the two-dimensional space vector (x, y), and z represents the overfocus light intensity map I z The distance between (x) and the focused light intensity diagram I0(x) in the direction of the optical axis, represents the phase of the grating to be measured, represents the gradient operator, k represents the wave number k = 2π / λ, λ is the wavelength of the light source, ψ represents the auxiliary function, represents the axial strength derivative.

6. The method according to claim 5, characterized in that The step of obtaining the phase distribution of the grating to be measured according to the Fourier transform property and the axial intensity derivative specifically includes: According to the Fourier transform properties and the axial intensity derivative, the expression of the auxiliary function is obtained: The auxiliary function obtains the phase distribution of the grating to be measured based on the Fourier property: Among them, q x represents the variable corresponding to x in Fourier space, q y represents the variable corresponding to y in Fourier space, F represents Fourier transform, F -1 represents the inverse Fourier transform, is the inverse Laplace operator, ψ represents the auxiliary function, represents the axial strength derivative.

7. The method according to claim 4, characterized in that The surface defect depth distribution information of the grating to be measured is as follows: Among them, h(x,y) represents the surface defect depth distribution information of the grating to be measured, represents the phase of the grating to be measured, and λ is the wavelength of the light source.

8. A computer device, characterized in that: The computer device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the method for measuring grating defects according to any one of claims 4 to 7.

9. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the processor executes the method for measuring grating defects as claimed in any one of claims 4 to 7.

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