Defect adjustment method for optical waveguide substrate

Abstract

The invention provides a defect adjustment method for an optical waveguide substrate, which comprises the following steps of: firstly, judging a local area of the substrate, and synchronously acquiring thickness information of the substrate based on position information of a contour area in the substrate; and judging whether the thickness of the contour region in the substrate meets a preset thickness or a threshold value of preset thickness change or not. And when the preset condition is not met, defect thickness adjustment is carried out on the position of the contour area to improve the substrate thickness value of the local area, so that the problem of local defects in the prior art is solved, the use yield of the positions of different contour areas when the substrate is used for manufacturing the optical waveguide is improved, and the imaging quality and contrast performance of the optical waveguide are improved. Meanwhile, the production cost is reduced, and the product utilization rate of the substrate is improved.

Description

Technical Field

[0001] This invention relates to the field of augmented reality display technology, and more particularly to a method for adjusting defects in an optical waveguide substrate. Background Technology

[0002] The image sharpness and contrast of an optical waveguide are crucial components affecting display quality. The substrate of the optical waveguide directly influences image sharpness and contrast, and the uniformity of the substrate thickness is a key factor affecting both.

[0003] Due to the size limitations of optical waveguide substrates, their surface shape is susceptible to variations in processing techniques. Currently, substrate inspection primarily relies on random sampling by manufacturers, which can easily introduce substandard substrates, thus reducing the yield of optical waveguide production. Variations in waveguide substrate surface shape mainly manifest as changes in substrate thickness. These thickness variations often occur locally, particularly in micrometer-scale areas, rather than affecting the entire substrate surface. Therefore, such localized defects are difficult to detect through random sampling.

[0004] Therefore, improving the production yield of optical waveguide substrates and enhancing the thickness uniformity of local areas of the substrate, especially the thickness of the region where the outline of the optical waveguide is located when fabricating grating structures, thereby improving imaging quality, is of great importance to those skilled in the art. Summary of the Invention

[0005] This invention provides a method for improving optical waveguide substrates, particularly for local areas of optical waveguide substrates, to improve thickness variations in local areas, solve problems existing in the prior art, improve the yield of optical waveguide fabrication on the substrate, improve and enhance the imaging quality (such as imaging effect, imaging clarity, etc.) and contrast performance of the optical waveguide, while reducing production costs and improving the yield of the substrate itself.

[0006] A method for adjusting defects in an optical waveguide substrate, characterized by comprising the following steps:

[0007] (1) Determine the position information of the contour region on the substrate when forming at least one contour region including an optical waveguide; obtain the position information and the thickness information of the substrate corresponding to the position information;

[0008] (2) Based on the location information and the thickness information, and simultaneously obtain the standard thickness value and standard thickness change threshold corresponding to the location information, determine whether the thickness information of the contour area at the location of the base meets the preset specifications;

[0009] (3) If the preset specifications are met, proceed directly to the next step; otherwise, if the preset specifications are not met, adjust the thickness of the contour area at the location of the base to adjust the thickness of at least one of the contour areas so that the thickness of the contour area at the location of the base meets the preset specifications.

[0010] Furthermore, it also includes step (4), which involves fabricating the structure of the optical waveguide in the region where the contour region is located, based on the thickness information of at least one contour region that meets the preset specifications at the location of the substrate.

[0011] Furthermore, in step (3), when the thickness of the contour region at the location of the base is adjusted for defects, the two planes of the base after the thickness adjustment are made parallel.

[0012] In some embodiments, when adjusting the thickness of the contour region at the location of the substrate in step (3), the value K of the maximum defect thickness needs to be determined by the following relationships (1) to (9):

[0013]

[0014] θ1=α1 (2)

[0015] α1=θ2+α2 (3)

[0016] θ2=α3 (4)

[0017] n1*sinα1=n2*sinα2 (5)

[0018] n2*sinα3=n3*sinα4 (6)

[0019]

[0020] d2=H1*tanθ2 (8)

[0021] d = d1 + d2 (9)

[0022] In the formula, K represents the value of the maximum thickness of the defect that needs to be adjusted at a certain defect location; R represents the radius of the surface defect profile; θ1 represents the angle between the defect profile and the horizontal direction of the substrate; θ2 represents the angle between the light ray after refraction on the first surface of the substrate and the normal direction of the substrate surface at the normal position; α1 represents the incident angle at the defect location on the first surface of the substrate; α2 represents the refraction angle of the light ray after refraction on the first surface of the substrate; α3 represents the incident angle of the light ray when it is incident on the second surface of the substrate; α4 represents the refraction angle of the light ray after refraction on the second surface of the substrate; H1 represents the nominal thickness of the substrate; H2 represents the horizontal distance between the substrate and the detector; d1 represents the horizontal deviation distance of the light beam from the exit position of the substrate relative to the incident position; d2 represents the horizontal distance between the second refraction exit position and the incident position; d represents the horizontal distance between the second refraction exit position and the detector; n1 and n3 represent the refractive index of air; n2 represents the refractive index of the substrate.

[0023] Furthermore, when adjusting defects, the volume of material V at a certain defect location needs to be adjusted by ≥

[0024]

[0025] Furthermore, in step (3), the refractive index of the filling material at different defect locations is similar to that of the substrate of the optical waveguide, or the difference between the two refractive indices is ≤0.5.

[0026] Furthermore, the position information in step (1) includes the position coordinates of at least one contour region in the substrate, the area of ​​at least one contour region, and the azimuth angle of at least one contour region.

[0027] Further, step (2) includes: based on the standard thickness value and standard thickness change threshold of the substrate of each optical waveguide at the corresponding position in the contour region obtained in advance, comparing and judging the position information and thickness information corresponding to the contour region obtained in step (1), judging the relationship with the standard thickness value and the standard thickness change threshold, judging whether it is within the threshold range, and then judging whether the thickness information of each contour region needs defect adjustment processing.

[0028] Furthermore, the threshold is no greater than 0.5 micrometers, further, the threshold is no greater than 0.3 micrometers, and even further, the threshold is no greater than 0.2 micrometers.

[0029] Furthermore, in step (3), the position thickness of the substrate corresponding to the contour area is adjusted for defects, while the position thickness of other areas of the substrate is not adjusted, so as to achieve local thickness adjustment of the substrate.

[0030] An optical waveguide substrate, wherein the substrate is prepared by the method described in any of the preceding embodiments.

[0031] The method provided by this invention first determines a local region of the substrate, based on the position information of the contour region within the substrate, and simultaneously acquires the thickness information of the substrate; it then determines whether the thickness of the substrate where the contour region is located meets a preset thickness or a preset thickness change threshold. When the preset condition is not met, the defect thickness at the location of the contour region is adjusted to improve the substrate thickness value in the local region, solve the local defect problem existing in the prior art, improve the yield of the substrate at different contour region locations when fabricating optical waveguides, improve the imaging quality and contrast performance of the optical waveguide, while reducing production costs and increasing the product utilization rate of the substrate itself. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of a defect structure of an optical waveguide substrate;

[0034] Figure 2 This is a schematic diagram of a second defect structure of an optical waveguide substrate;

[0035] Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure of the defect in the waveguide substrate;

[0036] Figure 4 This is a schematic diagram of the defect structure of the substrate of the optical waveguide, obtained through a detector.

[0037] Figure 5 for Figure 4 Schematic diagram of defect adjustment in rectangular region 1 of the substrate. Figure 1 ;

[0038] Figure 6 for Figure 4 Schematic diagram of defect adjustment in rectangular region 1 of the substrate. Figure 2 ;

[0039] Figure 7 This is a flowchart illustrating a method for adjusting defects in an optical waveguide substrate provided by the present invention. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0041] like Figures 1-2 As shown, localized areas on one side of the substrate of an optical waveguide may exhibit various defects such as "depressions" or "protrusions." When fabricating a grating structure on this surface, the impact of defects at different locations on the grating structure varies (the figure only shows several similar defects on one side of the substrate; it can be inferred that similar defects may also exist on the opposite side of the substrate, meaning that both surfaces of the substrate may have similar "depressions"). For example, defects in the central region of the substrate are unacceptable when fabricating a grating structure, especially in the area where the grating structure is located. However, some defects in the edge region of the substrate (such as those outside the outline of the optical waveguide) have a negligible impact on the waveguide grating structure because the grating structure will not be located in that edge region. Therefore, defects at different locations on the substrate have different effects on the grating structure for those skilled in the art. A substrate is acceptable when certain defects at the edge of the substrate do not affect the fabrication of the grating structure in the central region. Therefore, to a certain extent, by improving defects at different locations on the substrate, the utilization rate of the substrate can be increased, the cost of fabricating optical waveguides can be reduced, and economic benefits can be improved.

[0042] Further addressing the issues raised in the background section, this invention aims to correct defects in any surface region of an optical waveguide substrate, thereby improving the surface defect thickness. Specifically, it addresses localized contour regions on a surface of the optical waveguide substrate where a grating structure is located, adjusting internal defects at these contour regions. The proposed method first determines whether a localized region of the substrate meets a preset thickness or a preset thickness variation threshold. If the condition is not met, defect thickness adjustment is performed to improve the substrate thickness value in the localized region. This solves problems in existing technologies, increases the yield of substrates at different contour regions during optical waveguide fabrication, improves the imaging quality and contrast performance of the optical waveguide, reduces production costs, and increases the yield and efficiency of the substrate itself. This is beneficial to those skilled in the art.

[0043] Therefore, the present invention provides the following method, more specifically:

[0044] A method for adjusting defects in an optical waveguide substrate includes:

[0045] (1) Determine the position information of the contour region on the substrate when forming at least one contour region including an optical waveguide; obtain the position information and the thickness information of the substrate corresponding to the position information;

[0046] (2) Based on the location information and the thickness information, and simultaneously obtain the standard thickness value and standard thickness change threshold corresponding to the location information, determine whether the thickness information of the contour area at the location of the base meets the preset specifications;

[0047] (3) If the preset specifications are met, proceed directly to the next step; otherwise, if the preset specifications are not met, adjust the thickness of the contour area at the location of the base to adjust the thickness of at least one of the contour areas so that the thickness of the contour area at the location of the base meets the preset specifications.

[0048] The contour region referred to in this invention refers to the region where the edge contour of the optical waveguide is located.

[0049] The present invention provides a defect adjustment method for an optical waveguide substrate, which is particularly applicable to optical waveguides in which surface relief gratings, polarizing liquid crystal gratings, or other structures are formed on a certain surface of the substrate by imprinting or other means during the fabrication of diffractive optical waveguides. Furthermore, the present invention adjusts defects in a local area of ​​the optical waveguide substrate, especially in a specific location area of ​​the optical waveguide substrate where the grating structure is located, so that its thickness meets the preset requirements.

[0050] More specifically, in step (1), the position information of the contour region on the substrate is first determined when forming at least one contour region including the optical waveguide; the position information and the thickness information of the substrate corresponding to the position information are obtained. Specifically, the optical waveguide may often include multiple different contour regions, such as different shape ID designs, or multiple contour regions may be formed by imprinting and splicing in the same optical waveguide substrate. The location and size of the different contour regions may be different.

[0051] Based on the preset positions and number of contour regions, the position information of each contour region in the substrate is determined, and the position information when at least one contour region is included, as well as the thickness information of the substrate corresponding to the position information, are obtained. This position information includes multi-dimensional information such as the position coordinates of each contour region in the substrate, the area of ​​each contour region, and the azimuth angle of each contour region; and simultaneously, the thickness information of the substrate corresponding to the position information of each contour region in the substrate is obtained, including the thickness value and thickness variation value of each contour region.

[0052] Furthermore, the position and thickness information of each contour region on the substrate are obtained through a testing platform. The testing platform includes a laser source, a DOE (Distributed Optical Array), a wafer, a fixture, an industrial camera, and a PC. Testing is performed using either transmission or reflection methods. During testing, a horizontal or vertical laser line is emitted from the laser source; the DOE then shapes the line laser into a grid-like laser line array. The laser emitted from the laser source passes through the DOE and then through the optical waveguide substrate. The industrial camera captures the array image after projection or reflection through the optical waveguide substrate. The captured image is calculated, and the thickness value of each grid point is output. Based on the beam information at different positions on the optical waveguide, the relevant position information for each position and the thickness value of each grid at each position are obtained.

[0053] In step (2), based on the location information and the thickness information, and simultaneously obtaining the standard thickness value and standard thickness change threshold corresponding to the location information, it is determined whether the thickness information of the contour region at the location of the substrate meets the preset specifications; in detail, in this step, according to the standard thickness value and standard thickness change threshold corresponding to the location of each contour region of the substrate of each optical waveguide obtained in advance, the location information and thickness information corresponding to each contour region obtained in step (1) are compared and judged to determine the relationship with the standard thickness value and standard thickness change threshold, to determine whether it is within the threshold range, and then to determine whether the thickness information of each contour region needs to be corrected.

[0054] In this step, based on the batch number or ID of each optical waveguide, the standard thickness value of the substrate at the time of manufacture and the threshold for standard thickness variation can be obtained. Based on the predetermined threshold for standard thickness variation, it can be limited to no more than 0.5 micrometers, further, no more than 0.3 micrometers, or even no more than 0.2 micrometers. The standard thickness value is limited based on the substrate of different optical waveguides. The thickness value of different substrates may vary, and is determined according to different test objects. For example, the thickness value of the substrate is greater than or equal to 0.4 mm, or greater than or equal to 0.5 mm, etc.

[0055] In step (3), based on the judgment method of the aforementioned steps, if the preset specifications are met, the next step (4) is directly entered; otherwise, if the preset specifications are not met, the thickness of the contour area at the location of the base is adjusted to adjust the thickness of at least one of the contour areas so that the thickness of the contour area at the location of the base meets the preset specifications.

[0056] More specifically, such as Figure 3 As shown, Figure 1 or Figure 2A magnified cross-sectional view of a certain "depression" defect is shown, and this is used as one of the methods for defect adjustment, similar to the method for adjusting convex defects, such as... Figure 6 As shown. Suppose a cross-sectional view based on a certain "dent" defect, such as... Figure 3 and Figure 4 The substrate of the optical waveguide is divided into several regions, some of which contain defects as shown in regions 1, 2, and 3. Of course, the defects in each region can be different, and the type of defect can be either a "depression" or a "protrusion." Based on the acquired substrate image of the optical waveguide, as shown... Figure 4 As shown, the substrate is divided into several rectangular regions, each containing different defect types. Illustratively, for example, in rectangular region 1, being located in the center of the substrate, there is a possibility of fabricating a grating structure within it, as shown in the figure. The contour region containing the optical waveguide covers rectangular region 1; therefore, defect adjustment is needed for the positional defect in rectangular region 1. Furthermore, for positions like rectangular regions 2 and 3, being located at the edges of the substrate, the possibility of fabricating a grating structure at these locations is low due to considerations of panelization processes and subsequent cutting. Therefore, those skilled in the art can determine whether defect adjustment is necessary at these locations. Thus, considering the different locations of the optical waveguide contour regions and the defect conditions at different locations, the determination of whether thickness adjustment is needed during grating structure fabrication can be based on different imprinting or other methods. Figure 4 The diagram is for illustrative purposes only and does not represent the final area for fabricating the grating structure or the limitations on thickness adjustment of defect areas, nor does it represent the area where the final optical waveguide profile is located. This diagram does not impose any restrictions on these aspects.

[0057] Furthermore, the thickness of the contour region at the location of the substrate is adjusted to adjust the thickness of the contour region at the corresponding location on the substrate. Further explanation is provided, such as... Figure 5 As shown, it illustrates the laser emission from the substrate 10 after the laser beam passes through the substrate 10, as obtained by the detection device 20. Assuming... Figure 5 The location shown is Figure 4 The defect location area within the rectangular region 1. Furthermore, Figure 5 express Figure 3 This diagram illustrates the cross-section of a "depression" defect, showing only one side to demonstrate the need for thickness adjustment on the side where the defect is located. The gray area represents the optical waveguide substrate, and the colored area represents the region where the defect needs to be adjusted, specifically the area where the thickness will be modified.

[0058] like Figure 5 and Figure 3As shown, exemplarily, the substrate includes a first surface and a second surface disposed opposite to each other, and a depression defect exists on the first surface. For ease of calculation and analysis, one side contour of the depression defect is equivalent to a triangular region, as shown by the colored area in the figure. The colored area indicates the region where thickness adjustment is required. Simultaneously, assuming the surface contour of the "depression" defect is equivalent to a circular structure, the diameter of the circular structure of the surface contour can be determined from the acquired substrate image. Figure 5 The red lines in the diagram represent the path of light propagation, and the green lines represent the normal to the incident surface. The light enters the substrate from the first surface and exits from the substrate to the outside through the second surface. It is refracted on both the first and second surfaces. The refraction on the first surface is the first refraction, and the refraction on the second surface is the second refraction. The angle of incidence and the angle of refraction are both the angles between the light ray and the normal to the incident surface. In the following relationships (1) to (9), R represents the radius of the surface defect profile, K represents the value of the maximum thickness of the defect that needs to be adjusted at a certain defect location; θ1 represents the angle between the defect profile and the horizontal direction of the substrate; θ2 represents the angle between the light ray after refraction on the first surface of the substrate and the normal direction of the substrate surface at the normal position; α1 represents the angle between the light ray incident on the first surface and the normal direction of the substrate surface at the defect location, that is, the incident angle of the light ray at the defect location on the first surface of the substrate; α2 represents the refraction angle of the light ray after refraction on the first surface of the substrate; α3 represents the incident angle of the light ray when it is incident on the second surface of the substrate; α4 represents the refraction angle of the light ray after refraction on the second surface of the substrate; H1 represents the nominal thickness of the substrate; H2 represents the horizontal distance between the substrate and the detector; d1 represents the horizontal deviation distance of the light beam from the exit position of the substrate relative to the incident position; d2 represents the horizontal distance between the second refraction exit position and the incident position; d represents the horizontal distance between the second refraction exit position and the detector; n1 and n3 represent the refractive index of air; n2 represents the refractive index of the substrate.

[0059] Therefore, in order to calculate the value of K, the following calculation method is specified:

[0060]

[0061] θ1=α1 (2)

[0062] α1=θ2+α2 (3)

[0063] θ2=α3 (4)

[0064] n1*sinα1=n2*sinα2 (5)

[0065] n2*sinα3=n3*sinα4 (6)

[0066]

[0067] d2=H1*tanθ2 (8)

[0068] d = d1 + d2 (9)

[0069] K can be calculated based on the above formulas (1) to (9), where n1 = n3 = 1, d1 can be calculated by the detector, and H1 and H2 are known.

[0070] Therefore, the maximum thickness K of the defect that needs to be adjusted at a certain location is calculated based on the radius R of the surface defect profile. The defect size at a certain location can be approximated as an inverted cone structure, thus the volume of material that needs to be adjusted at that defect location can be obtained.

[0071] Based on the above method, the volume size that needs to be adjusted for a defect at a certain location is obtained. Similarly, information on defects at several different locations and the volume size of the material to be adjusted are obtained. The volume sizes of the different adjustment materials at different locations and the specific defect locations are stored in an image of the optical waveguide substrate, forming a thickness adjustment image. Based on the thickness adjustment image, the thickness of defects at different locations is adjusted to compensate for the material in each defect region, thus realizing the defect adjustment operation.

[0072] In step (3), the position thickness of the substrate corresponding to the contour area is adjusted for defects, while the position thickness of other areas of the substrate is not adjusted relative to the contour area, so as to realize the thickness adjustment of the local area of ​​the substrate, thereby improving the thickness of the contour area where the grating is located, and improving the accuracy of grating structure fabrication and substrate utilization efficiency.

[0073] After the thickness adjustment is completed, the adjusted surface can be leveled using the processing technology in this field, so that the surfaces of the substrate remain parallel in different contour areas, so as to facilitate the fabrication of the grating structure.

[0074] The thickness adjustment range for different contour regions is at the micrometer level; at the same time, the refractive index of the filling material at different defect locations is similar to that of the substrate, or the difference between the two refractive indices is ≤0.5.

[0075] Furthermore, such as Figure 6 The diagram illustrates another type of defect, including a "protrusion." The gray area represents the substrate of the optical waveguide, and the colored area represents the region where the defect needs to be adjusted. Based on the aforementioned embodiments, the volume of material requiring adjustment in the colored area can be calculated using the same optical equation calculation method. This will not be repeated here.

[0076] certainly Figure 5 , Figure 6For illustrative purposes only, due to the complexity of defects in actual optical waveguide substrates, this invention only illustrates defects commonly found in the art, such as "dimples" and "protrusions," in specific embodiments. Different defect types are equated to triangular or conical regions that need adjustment to facilitate the calculation of thickness and volume. The invention also demonstrates how to adjust the thickness and volume of these two common defects to improve the local structure of the optical waveguide substrate. After the defect thickness is adjusted, the two opposing surfaces of the substrate where the grating structure is located are parallel to each other, thereby improving the local optical total internal reflection effect and thus increasing the utilization rate of existing optical waveguide substrates.

[0077] Furthermore, after step (3), the method further includes step (4), which involves fabricating the structure of the optical waveguide in the region where the contour region is located, based on the thickness information of at least one contour region that meets the preset specifications at the location of the substrate.

[0078] In detail, in this step, after the optical waveguide substrate has undergone the defect judgment and defect thickness adjustment in the above steps (1) to (3), when the thickness information of the contour area at the location of the substrate meets the preset conditions, a diffraction grating structure is directly fabricated in the area where the contour area that meets the preset specifications is located, thus forming an optical waveguide with a grating structure.

[0079] In this invention, when fabricating a grating structure, it is first determined whether a grating structure needs to be fabricated within a certain area of ​​the substrate. If a grating structure is required, it is then determined whether the thickness within that contour area meets a preset threshold, and thickness adjustment is performed accordingly. Based on different imposition methods of the working master and the position of the working master during printing, different judgments are made for the locations of different contour areas. This allows for efficient utilization of substrates with different defects, improving the selectivity of areas for fabricating grating structures.

[0080] The method provided by this invention first determines a local region of the substrate, based on the position information of the contour region within the substrate, and simultaneously acquires the thickness information of the substrate; it then determines whether the thickness of the substrate where the contour region is located meets a preset thickness or a preset thickness change threshold. When the preset condition is not met, the defect thickness at the location of the contour region is adjusted to improve the substrate thickness value in the local region, solve the local defect problem existing in the prior art, improve the yield of the substrate at different contour region locations when fabricating optical waveguides, improve the imaging quality and contrast performance of the optical waveguide, while reducing production costs and increasing the product utilization rate of the substrate itself.

[0081] Meanwhile, this invention provides an optical waveguide substrate, which is prepared by the method described in any of the foregoing embodiments. This allows the prepared optical waveguide substrate to adapt to variations in different grating profile regions, improving product utilization and reducing the defect rate of defective substrates. For those skilled in the art, this can significantly reduce production costs and improve economic efficiency.

[0082] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method of defect trimming of an optical waveguide substrate, characterized by, The method comprises the following steps: (1) judging the position information of the profile region including at least one optical waveguide on the substrate, obtaining the position information and the thickness information of the substrate corresponding to the position information; (2) judging whether the thickness information of the profile region on the substrate meets the preset specification based on the position information and the thickness information, and simultaneously obtaining the standard thickness value and the standard thickness variation threshold value corresponding to the position information; (3) when the preset specification is met, directly entering the next step; otherwise, when the preset specification is not met, adjusting the thickness of the profile region on the substrate to adjust the thickness of the position corresponding to the profile region, so that the thickness of the position corresponding to the profile region meets the preset specification.

2. The method of claim 1, wherein, Further, the method further comprises step (4): based on the thickness information of at least one profile region on the substrate meeting the preset specification, manufacturing the structure of the optical waveguide in the region where the profile region is located.

3. The method according to claim 1 or 2, characterized in that, In the step (3), the thickness of the profile region on the substrate is adjusted to make the two opposite planes of the substrate after thickness adjustment parallel.

4. The method of claim 3, wherein, In the step (3), the maximum thickness adjustment value K of the defect is determined by the following relations (1)-(9): θ1=α1 (2) α1=θ2+α2 (3) θ2=α3 (4) n1*sinα1=n2*sinα2 (5) n2*sinα3=n3*sinα4 (6) d2=H1*tanθ2 (8) d=d1+d2 (9) In the formula, K represents the maximum thickness adjustment value of the defect at a certain defect position; R represents the radius of the surface defect profile; θ1 represents the angle between the defect profile and the horizontal direction of the substrate; θ2 represents the angle between the normal direction of the substrate surface at the normal position and the normal direction of the substrate surface after the light is refracted at the first surface of the substrate; α1 represents the incident angle of the defect position incident to the first surface of the substrate; α2 represents the refraction angle of the light after being refracted at the first surface of the substrate; α3 represents the incident angle of the light incident to the second surface of the substrate; α4 represents the refraction angle of the light after being refracted at the second surface of the substrate; H1 represents the nominal thickness of the substrate; H2 represents the distance between the substrate and the detector; d1 represents the horizontal deviation distance of the light beam exit position relative to the incident position; n1 and n3 represent the refractive index of air; n2 represents the refractive index of the substrate.

5. The method of claim 4, wherein, Further, when adjusting defects, the volume of material at a defect location needs to be adjusted 6. The method of claim 5, wherein, In the step (3), the refractive index of the filling material at different defect positions is close to the refractive index of the substrate of the optical waveguide, or the difference between the two refractive indexes is ≤0.

5.

7. The method of claim 1, wherein, The position information in the step (1) includes the position coordinates of the profile region in the substrate, the area of the profile region, and the azimuth angle of the profile region.

8. The method of claim 1, wherein, The step (2) comprises: comparing the position information and the thickness information corresponding to the profile region obtained by the step (1) with the standard thickness value and the standard thickness variation threshold of the position of the substrate of each optical waveguide corresponding to the profile region obtained in advance, judging the relationship between the standard thickness value and the standard thickness variation threshold, judging whether it is within the threshold range, and further judging whether the thickness information of each profile region needs defect adjustment processing.

9. The method of claim 8, wherein, The threshold is not greater than 0.5 microns, and further, the threshold is not greater than 0.3 microns.

10. The method of claim 1, wherein, In the step (3), the position thickness of the substrate corresponding to the profile region is adjusted for defects, and the position thickness of other regions of the substrate is not adjusted, so as to realize local thickness adjustment of the substrate.

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