Method for calculating internal stress of optical element based on decoupling surface topography from reflection data

Abstract

The application discloses a kind of optical element inner stress calculation methods based on decoupling surface appearance of reflection data, solve the problem that existing technology cannot obtain the real internal stress distribution after removing surface interference when optical element transmission measurement, specifically includes steps 1, the first reflection wavefront phase data and total transmission wavefront phase data of target optical element are collected, and the transmission phase delay data of target optical element is obtained;Step 2, the coordinate system of first reflection wavefront phase data is aligned with the coordinate system of total transmission wavefront phase data, and first reflection wavefront phase data is consistent with transmission phase delay resolution, to obtain third reflection wavefront phase data;Step 3, the actual thickness distribution of target optical element is calculated by third reflection wavefront phase data;Step 4, the inner stress distribution of target optical element is calculated by transmission phase delay data and the actual thickness distribution, and the inner stress calculation of target optical element is completed.

Description

Technical Field

[0001] This invention relates to a method for calculating the internal stress of optical elements, specifically a method for calculating the internal stress of optical elements based on decoupling surface morphology from reflection data. Background Technology

[0002] In the manufacturing and testing of precision optical components (such as molded glass lenses, laser crystals, and mobile phone cover glass), it is of great significance to simultaneously evaluate their surface quality (such as surface accuracy, roughness, and scratches) and internal quality (such as residual stress and material uniformity).

[0003] Existing detection technologies typically employ a discrete approach: surface morphology is measured using a white light interferometer or confocal microscope; internal stress (birefringence) is measured using a polarization microscope or photoelasticity analyzer. This discrete measurement method suffers from low efficiency and high equipment costs, and because optical components move between different devices, it is difficult to achieve pixel-level data correspondence.

[0004] Chinese invention patent CN121275641A discloses a comprehensive microscopic measurement system and method for simultaneous multi-parameter measurement. By setting up a transmission illumination module, a reflection illumination module, a semi-transparent mirror switching mechanism, and a complex amplitude measurement instrument for the light field, it achieves in-situ acquisition of reflected and transmitted light from optical elements at the same workstation, effectively solving the efficiency problem of hardware integration and data acquisition. However, this invention does not deeply address the "physical coupling" problem at the data level. In optical principles, when a beam of light passes through an optical element, the phase information it carries is the integral superposition of the phase difference caused by changes in surface thickness and the phase difference caused by internal refractive index inhomogeneity (such as stress). For optical elements with microscopic textures, polishing marks, or thickness wedges on the surface, traditional transmission measurements may misinterpret these surface features as internal stress stripes, leading to serious measurement errors. While relying solely on hardware switching acquisition can obtain multi-dimensional images, without effective data fusion and decoupling algorithms, it is still impossible to obtain the true internal stress distribution after removing surface interference. Summary of the Invention

[0005] To address the technical problem that existing technologies cannot obtain the true internal stress distribution after removing surface interference during transmission measurements of optical components, this invention provides a method for calculating the internal stress of optical components based on decoupling surface morphology from reflection data.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for calculating the internal stress of an optical element based on decoupling surface topography from reflection data is characterized by the following steps:

[0008] Step 1: Collect the first reflected wavefront phase data and the total transmitted wavefront phase data of the target optical element, and obtain the transmission phase delay data of the target optical element;

[0009] Step 2: Align the coordinate system of the first reflected wavefront phase data with the coordinate system of the total transmitted wavefront phase data, and make the resolution of the first reflected wavefront phase data consistent with that of the transmitted phase delay, to obtain the third reflected wavefront phase data.

[0010] Step 3: Calculate the actual thickness distribution of the target optical element using the third reflection wavefront phase data;

[0011] Step 4: Calculate the internal stress distribution of the target optical element using the transmission phase delay data and the actual thickness distribution, thus completing the internal stress calculation of the target optical element.

[0012] Furthermore, step 1 specifically includes:

[0013] Acquire the first reflected wavefront phase data of the target optical element and total transmitted wavefront phase data And acquire transmission phase retardation data of the target optical element. ; For the first type of data pixel array index; This is the index for the second type of data pixel array.

[0014] Furthermore, in step 2, the phase data of the first reflected wavefront is... coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. Then the second reflected wavefront phase data Mapping calculations to transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront was obtained. .

[0015] Furthermore, step 2 specifically includes:

[0016] Step 2.1: Acquire the phase data of the first reflected wavefront of the target optical element. and total transmitted wavefront phase data The first common feature point;

[0017] Step 2.2: Based on the first common feature point, the first reflected wavefront phase data... coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. ;

[0018] Step 2.3: Transfer the phase data of the second reflected wavefront. Resolution mapping calculation to transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront were obtained. .

[0019] Furthermore, step 2.2 specifically includes:

[0020] Step 2.21: Obtain the first reflected wavefront phase data based on the first common feature point. and total transmitted wavefront phase data offset between ;

[0021] Step 2.22: Based on the offset Phase data of the first reflected wavefront Perform translation correction to ensure that the phase data of the first reflected wavefront is correct. coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. .

[0022] Furthermore, step 2.3 specifically includes:

[0023] The second reflected wavefront phase data is transformed using a spatial mapping transformation model. Resolution mapping calculation to transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront were obtained. .

[0024] Furthermore, step 3 specifically includes:

[0025] Step 3.1: Using the third reflected wavefront phase data Calculate the surface height distribution of the target optical element :

[0026] ;

[0027] Among them, Incident light wavelength;

[0028] Step 3.2, based on the surface height distribution Calculate the actual thickness distribution of the target optical element :

[0029]

[0030] in, This represents the minimum thickness of the target optical element.

[0031] Furthermore, step 4 specifically involves:

[0032] Transmission phase delay data obtained in step 1 and actual thickness distribution Calculate the internal stress distribution of the target optical element. :

[0033] ;

[0034] in, The stress optical constant of the target optical element;

[0035] Complete the internal stress calculation of the target optical element.

[0036] Further, in step 1, the first reflected wavefront phase data and the total transmitted wavefront phase data of the target optical element are acquired by the wavefront sensor, and the transmission phase delay data of the target optical element are acquired by the camera.

[0037] The beneficial effects of this invention are:

[0038] 1. True decoupling at the physical level has been achieved;

[0039] This invention breaks through the limitation of "what you see is what you get" in traditional transmission measurement. By introducing reflected wavefront phase data as a geometric reference and utilizing the physical optical path difference principle, it successfully separates surface morphology noise (such as scratches and processing textures) mixed in the transmission signal from the internal stress signal, significantly improving the reliability of the internal stress distribution of the target optical element.

[0040] 2. Solved the problem of cross-source data registration;

[0041] This invention overcomes the problem that transmitted and reflected light paths are difficult to be completely coaxial and have the same magnification in actual engineering by registering spatial coordinate systems, ensuring the accuracy of differential operations at the micro-pixel level and avoiding edge artifacts.

[0042] 3. Improved the accuracy of stress quantification;

[0043] This invention calculates the actual thickness of the target optical element by calculating the surface height distribution, thus correcting the stress calculation error caused by the uneven thickness of the optical element in traditional photoelastic measurement. It is particularly suitable for the quality inspection of aspherical lenses or wedge-shaped glass.

[0044] 4. Maximize the value of hardware;

[0045] This invention fully utilizes the multi-dimensional data acquisition capabilities of existing hardware systems (Chinese invention patent CN121275641A, "A Comprehensive Microscopic Measurement System and Measurement Method for Multi-parameter Synchronous Measurement"), upgrading and achieving a "1+1>2" effect, enabling high-end composite detection functions without increasing additional hardware costs. Attached Figure Description

[0046] Figure 1 This is a flowchart of an embodiment of the method for calculating the internal stress of an optical element based on decoupling surface morphology from reflection data according to the present invention. Detailed Implementation

[0047] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. 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 are within the scope of protection of the present invention.

[0048] The present invention provides a method for calculating the internal stress of an optical element based on the decoupling of surface morphology from reflection data, which adopts the integrated microscopic measurement system disclosed in Chinese invention patent CN121275641A entitled "An integrated microscopic measurement system and its measurement method for multi-parameter synchronous measurement".

[0049] like Figure 1 As shown, the method for calculating the internal stress of this optical element includes the following steps:

[0050] Step 1: Collect the first reflection wavefront phase data and the total transmission wavefront phase data of the target optical element, and obtain the transmission phase delay data of the target optical element.

[0051] In this embodiment, the target optical element is kept in a fixed position on the stage, and the first reflected wavefront phase data of the target optical element is acquired by a wavefront sensor with low resolution. and total transmitted wavefront phase data The transmission phase retardation data of the target optical element is acquired and calculated using a high-resolution camera. . For the first type of data pixel array index; For the second type of data pixel array index, and All data are independent variables, representing two-dimensional full-field images, rather than sparse point sampling.

[0052] Step 2: Align the coordinate system of the first reflected wavefront phase data with the coordinate system of the total transmitted wavefront phase data, and make the resolution of the first reflected wavefront phase data consistent with that of the transmitted phase delay, to obtain the third reflected wavefront phase data.

[0053] In this embodiment, the first reflected wavefront phase data coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. Then, the second reflected wavefront phase data Resolution and transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront were obtained. Specifically, it includes the following steps:

[0054] Step 2.1: Acquire the first reflection wavefront phase data of the target optical element. and total transmitted wavefront phase data The first common feature point.

[0055] Step 2.2: Based on the first common feature point mentioned above, the first reflected wavefront phase data... coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. Specifically, it includes:

[0056] Step 2.21: Obtain the first reflected wavefront phase data based on the first common feature point. Phase data of the total transmitted wavefront Spatial translational offset introduced by optical path switching .

[0057] Step 2.22: Based on the offset mentioned above Phase data of the first reflected wavefront Perform pixel-level (or sub-pixel-level) translation correction to ensure that the phase data of the first reflected wavefront is accurate. coordinate system and total transmitted wavefront phase data The coordinate systems are perfectly aligned, eliminating the inherent translational deviation of the transmission and reflection paths caused by the semi-transparent and semi-reflective mirrors, thus obtaining the phase data of the second reflected wavefront. .

[0058] Step 2.3: Transfer the phase data of the second reflected wavefront. Resolution mapping calculation to transmission phase delay data With completely consistent resolution, the phase data of the third reflected wavefront were obtained. .

[0059] In this embodiment, an existing spatial mapping transformation model capable of mapping from a low-resolution global reference coordinate system to a high-resolution camera coordinate system is used to transform the second reflected wavefront phase data. The resolution was improved to match the transmission phase delay data. With consistent resolution, high-resolution third reflection wavefront phase data were obtained. .

[0060] Step 3: Calculate the actual thickness distribution of the target optical element using the third reflection wavefront phase data; specifically including:

[0061] Step 3.1: Using the third reflected wavefront phase data Calculate the surface height distribution of the target optical element :

[0062] ;

[0063] Among them, Incident light wavelength;

[0064] Step 3.2, based on the surface height distribution Calculate the actual thickness distribution of the target optical element :

[0065]

[0066] in, This represents the minimum thickness of the target optical element.

[0067] Step 4: Calculate the internal stress distribution of the target optical element using the transmission phase retardation data and the actual thickness distribution;

[0068] In this embodiment, specifically: the transmission phase delay data obtained through step 1 and actual thickness distribution Calculate the internal stress distribution of the target optical element. :

[0069] ;

[0070] in, The stress optical constant of the target optical element;

[0071] Complete the internal stress calculation of the target optical element.

[0072] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the internal stress of an optical element based on decoupling surface morphology from reflection data, characterized in that, Includes the following steps: Step 1: Collect the first reflected wavefront phase data and the total transmitted wavefront phase data of the target optical element, and obtain the transmission phase delay data of the target optical element; Step 2: Align the coordinate system of the first reflected wavefront phase data with the coordinate system of the total transmitted wavefront phase data, and make the resolution of the first reflected wavefront phase data consistent with that of the transmitted phase delay, to obtain the third reflected wavefront phase data. Step 3: Calculate the actual thickness distribution of the target optical element using the third reflection wavefront phase data; Step 4: Calculate the internal stress distribution of the target optical element using the transmission phase delay data and the actual thickness distribution, thus completing the internal stress calculation of the target optical element.

2. The method for calculating the internal stress of an optical element based on decoupling surface morphology from reflection data according to claim 1, characterized in that, Step 1 is as follows: Acquire the first reflected wavefront phase data of the target optical element and total transmitted wavefront phase data And acquire transmission phase retardation data of the target optical element. ; For the first type of data pixel array index; This is the index for the second type of data pixel array.

3. The method for calculating the internal stress of optical elements based on decoupled surface morphology using reflection data according to claim 2, characterized in that: In step 2, the phase data of the first reflected wavefront is... The coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. Then the second reflected wavefront phase data Mapping calculations to transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront was obtained. .

4. The method for calculating the internal stress of an optical element based on decoupled surface morphology using reflection data according to claim 2 or 3, characterized in that, Step 2 specifically includes: Step 2.1: Acquire the phase data of the first reflected wavefront of the target optical element. and total transmitted wavefront phase data The first common feature point; Step 2.2: Based on the first common feature point, the first reflected wavefront phase data... The coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. ; Step 2.3: Transfer the phase data of the second reflected wavefront. Resolution mapping calculation to transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront were obtained. .

5. The method for calculating the internal stress of an optical element based on decoupling surface morphology from reflection data according to claim 4, characterized in that, Step 2.2 specifically includes: Step 2.21: Obtain the first reflected wavefront phase data based on the first common feature point. and total transmitted wavefront phase data offset between ; Step 2.22: Based on the offset Phase data of the first reflected wavefront Perform translation correction to ensure that the phase data of the first reflected wavefront is correct. The coordinate system and total transmitted wavefront phase data By aligning the coordinate systems, the phase data of the second reflected wavefront can be obtained. .

6. The method for calculating the internal stress of an optical element based on decoupled surface morphology using reflection data according to claim 5, characterized in that, Step 2.3 specifically involves: The second reflected wavefront phase data is transformed using a spatial mapping transformation model. Resolution mapping calculation to transmission phase delay data With consistent resolution, the phase data of the third reflected wavefront were obtained. .

7. The method for calculating the internal stress of an optical element based on decoupled surface morphology using reflection data according to claim 6, characterized in that, Step 3 specifically includes: Step 3.1: Using the third reflected wavefront phase data Calculate the surface height distribution of the target optical element : ； Among them, Incident light wavelength; Step 3.2, based on the surface height distribution Calculate the actual thickness distribution of the target optical element : ； in, This represents the minimum thickness of the target optical element.

8. The method for calculating the internal stress of an optical element based on decoupled surface morphology using reflection data according to claim 7, characterized in that, Step 4 is as follows: Transmission phase delay data obtained in step 1 and actual thickness distribution Calculate the internal stress distribution of the target optical element. : ； in, The stress optical constant of the target optical element; Complete the internal stress calculation of the target optical element.

9. The method for calculating the internal stress of an optical element based on decoupled surface morphology using reflection data according to claim 1, characterized in that: In step 1, the first reflected wavefront phase data and the total transmitted wavefront phase data of the target optical element are acquired by the wavefront sensor, and the transmission phase delay data of the target optical element are acquired by the camera.

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