Method and apparatus for measuring surface stress of optical elements

Abstract

This application proposes a method and apparatus for measuring the surface stress of an optical element, relating to the field of polarization and stress measurement technology for film-based structural elements. The measuring apparatus for implementing the measurement method includes a light source, a polarizer, a filter, a beam expander, a collimator, an analyzer, and a photodetector. The measurement method includes: acquiring a first signal energy output by the photodetector; the first signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test on the stage when the measuring apparatus is in a first operating condition; acquiring a second signal energy output by the photodetector; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test when the measuring apparatus is in a second operating condition; determining first light intensity distribution information based on the first signal energy, and determining second light intensity distribution information based on the second signal energy; and acquiring the surface stress information of the element under test based on the first and second light intensity distribution information.

Description

Technical Field

[0001] This application relates to the field of polarization and stress measurement technology for film-based structural elements, and in particular to a method and apparatus for measuring surface stress of optical elements. Background Technology

[0002] Flexible electronic devices with membrane-based structures contain a large number of high-precision components. The testing and evaluation of these components are crucial to ensuring the overall reliability of the membrane-based structure. Flexible electronic devices are generally membrane-based structures; therefore, in the mechanical force evaluation process, only planar stress needs to be considered, especially the surface stress that reflects the contact state. Summary of the Invention

[0003] This application provides a method and apparatus for measuring the surface stress of an optical element.

[0004] According to a first aspect of this application, a method for measuring the surface stress of an optical element is provided. The measuring device for implementing the method is a device designed based on the Fresnel reflection formula for anisotropic media. The measuring device includes a light source, and along the optical path direction output from the light source, a polarizer, a filter beam expander collimator, a beam splitter, a stage, an imaging lens, an analyzer, and a photodetector are arranged sequentially. The measurement method includes:

[0005] The first signal energy output by the photodetector is obtained; the first signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the component under test on the stage when the measuring device is in the first operating condition.

[0006] The second signal energy output by the photodetector is obtained; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test when the measuring device is in the second operating condition.

[0007] The first light intensity distribution information is determined based on the first signal energy, and the second light intensity distribution information is determined based on the second signal energy;

[0008] The surface stress information of the component under test is obtained based on the first light intensity distribution information and the second light intensity distribution information.

[0009] According to a second aspect of this application, a device for measuring the surface stress of an optical element is provided, comprising a light source, and arranged sequentially along the optical path direction output from the light source: a polarizer, a filter beam expander and collimator, a beam splitter, a stage, an imaging lens, an analyzer, and a photodetector; wherein the measuring device further comprises:

[0010] A control module connected to the photodetector, the control module storing a computer program, which, when executed, can perform the method described in the first aspect above.

[0011] According to a third aspect of this application, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it is capable of performing the method described in the first aspect above.

[0012] According to a fourth aspect of this application, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, is capable of performing the method described in the first aspect above.

[0013] According to the technical solution of this application, by acquiring the first signal energy output by the photodetector under the first working condition and the second signal energy output by the photodetector under the second working condition, the surface stress information of the component under test is determined using the first signal energy and the second signal energy. This ensures that stress information caused by changes in the surface shape of the component under test is not introduced when calculating the surface stress of the component under test, so that the measurement process can obtain relevant data more directly, reduce the number of experiments, improve the measurement efficiency, avoid the angle error caused by multiple measurements, ensure the accuracy of the measurement results, and have low environmental requirements during the measurement process. The optical path structure and data recording process are simple and the operation is easy. Attached Figure Description

[0014] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0015] Figure 1 A flowchart illustrating a method for measuring surface stress of an optical element, provided as an embodiment of this application;

[0016] Figure 2 A flowchart illustrating another method for measuring surface stress of an optical element provided in an embodiment of this application;

[0017] Figure 3 A flowchart illustrating another method for measuring surface stress of an optical element provided in an embodiment of this application;

[0018] Figure 4 A positional relationship diagram of a device for measuring surface stress of an optical element provided in an embodiment of this application;

[0019] Figure 5 This is a structural block diagram of an electronic device for measuring the surface stress of an optical element, as provided in an embodiment of this disclosure. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0021] Flexible electronic devices with film-based structures contain numerous high-precision components, and the testing and evaluation of these components are crucial to ensuring the overall reliability of the film-based structure. Flexible electronic devices are generally film-based structures; therefore, in the mechanical force evaluation process, only plane stress needs to be considered, especially surface stress, which reflects the contact state. Among related technologies, the most commonly used surface stress evaluation methods are the finite element method and the contact polarization measurement method.

[0022] Among them, the finite element method is a method of simulating real physical systems (geometry and load conditions) using mathematical approximations.

[0023] Contact polarization measurement is a measurement method that describes the various properties of a target material by analyzing the electromagnetic waves transmitted, reflected, refracted, and even diffracted by the target material.

[0024] However, the finite element method is highly dependent on loads and boundary conditions, both of which are difficult to determine in actual experiments. Contact polarization measurement methods use prisms or other coupled optical modules to display the surface stress of components as stripes. This method is simple to construct, but the resulting measurement field of view is small, requiring a moving scan to obtain the full-field surface stress of the component. Furthermore, contact measurements cannot reflect the intrinsic stress of the component to some extent. Therefore, a non-contact method for full-field surface stress measurement is needed.

[0025] In full-field stress measurement, the traditional method involves obtaining a fringe distribution image related to the stress of the element under test under a circularly polarized light field, including iso-arithmetic lines reflecting shear force and iso-inclined lines reflecting fast axis distribution. In the last two decades, thanks to advancements in digital image processing, researchers have proposed several methods combining holography or other interferometry with phase-shifting photoelasticity for stress detection. The typical approach is to first obtain iso-arithmetic and iso-inclined lines through several steps of phase-shifting photoelasticity. These methods have been widely applied in full-field photoelasticity measurement, and experimental results agree well with theoretical numerical analysis. However, it is undeniable that due to phase-shifting interference, these methods introduce phase-shifting errors caused by linear and quadratic reference phase deviations.

[0026] To address the aforementioned problems, this application discloses a method for measuring the surface stress of an optical element. The method involves irradiating the element under test with a full-aperture light beam, obtaining bright-field and dark-field light intensities by rotating a polarizer and analyzer, and finally obtaining the surface stress of the element by combining the law of photomechanics. The method for measuring the surface stress of an optical element according to embodiments of this application is described below with reference to the accompanying drawings.

[0027] Figure 1 This is a flowchart illustrating a method for measuring surface stress of an optical element according to an embodiment of this application. It should be noted that the measuring device used to implement the measurement method in this embodiment can be a device designed based on the Fresnel reflection formula for anisotropic media.

[0028] In one implementation, such as Figure 4 As shown, the measuring device includes a light source 1, and along the optical path direction output from the light source 1 are, in sequence, a polarizer 2, a filter beam expander collimator 3, a beam splitter 4, a stage 5, an imaging lens 6, an analyzer 7, and a photodetector 8.

[0029] Among them, the polarizer 2 is a device used to obtain polarized light from natural light. It should be noted that polarized light is a type of light whose vibration plane is limited to a certain fixed direction.

[0030] The filter beam expander collimator 3 is used to convert divergent light into parallel light, ensuring that the light is coupled into the required device or the most efficient optical signal is received.

[0031] Beam splitter 4 is used to separate the desired resonant absorption lines from natural light.

[0032] Imaging lens 6 is used for optical imaging operations, which facilitates the subsequent acquisition of reflected light by photodetector 8.

[0033] The analyzer 7, also known as a polarizer, is mainly used to convert incident light into linearly polarized light for output.

[0034] The photodetector 8 is used to acquire images of reflected light, providing a basis for subsequent analysis and calculation of the isoclimate and isoclinal lines of the surface stress of the component under test.

[0035] In one implementation, light source 1 emits a beam that is split. The split beam passes through polarizer 2, which performs polarization processing to make the beam have only a single direction. Then, the split beam passes through filter beam expander collimator 3, which performs filtering and beam expansion processing on the split beam and makes it parallel light instead of divergent light. The split beam then passes through beam splitter 4, which separates the resonant absorption lines required in the split beam. The processed beam illuminates the device under test on stage 5. The reflected light from the device under test is then processed by imaging lens 6 and analyzer 7 to polarize the reflected light. Finally, the reflected light is imaged on photodetector 8, and the signal energy of the reflected light is detected by photodetector 8.

[0036] It should be noted that, based on the aforementioned measuring device, this application proposes a method for measuring the surface stress of an optical element. For example... Figure 1 The method for measuring the surface stress of this optical element includes the following steps:

[0037] Step 101: Obtain the first signal energy output by the photodetector.

[0038] In this embodiment of the application, the first signal energy can be the signal energy obtained by the photodetector collecting the reflected light generated by the component under test on the stage when the measuring device is in the first working condition.

[0039] In this embodiment, a spatial rectangular coordinate system is established, where the direction of the optical axis of the beam splitter is the z-direction. An experimental reference xy coordinate system is established in a plane perpendicular to the optical axis of the beam splitter, where the x-direction is horizontal and the y-direction is perpendicular to the x-direction in the plane. It should be noted that this first operating condition refers to the situation where the polarization direction of the polarizer's polarization plane is 0° with respect to the x-direction of the beam splitter, and the polarization direction of the analyzer is also 0° with respect to the x-direction of the beam splitter. Furthermore, in this first operating condition, both the polarization direction of the polarization plane and the polarization direction of the analyzer are fixed.

[0040] As an example, the light source is positioned in a fixed location, ensuring stable illumination without any positional change. The component under test (DUT) is placed on a stage, and the stage position is adjusted to ensure that the beam emitted by the light source illuminates the stage. When detecting surface stress on the optical component, the beam from the light source passes through a polarizer, a filter, a beam expander, and a collimator to obtain parallel light. This parallel light then passes through a beam splitter and illuminates the DUT, capturing the reflected light. The reflected light is then processed by an imaging lens and an analyzer before being imaged onto a photodetector. The photodetector outputs a first signal energy based on the image formed by the reflected light.

[0041] It should be noted that the measuring device is in its first operating condition, and the light field region on the stage is a bright field. A bright field means that the light source is at a certain angle to the object being measured, so that most of the light is reflected and captured by the camera.

[0042] Step 102: Obtain the second signal energy output by the photodetector; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test when the measuring device is in the second operating condition.

[0043] In this embodiment, a spatial rectangular coordinate system is established, wherein the direction of the optical axis of the beam splitter is the z-direction, and an experimental reference xy coordinate system is established in a plane perpendicular to the optical axis of the beam splitter, wherein the x-direction in the xy coordinate system is the horizontal direction, and the direction perpendicular to the x-direction in the plane is the y-direction. It should be noted that this second operating condition refers to the polarization direction of the polarizer's polarization plane being 0° with respect to the x-direction of the beam splitter, and the polarization direction of the analyzer being 90° with respect to the x-direction of the beam splitter. Furthermore, in the second operating condition, both the polarization direction of the polarization plane and the polarization direction of the analyzer are fixed.

[0044] As an example, after acquiring the first signal energy output by the photodetector, the polarization direction of the polarization plane of the polarizer is kept unchanged, and the polarization direction of the analyzer is adjusted so that the polarization direction of the analyzer is 90° with the x-direction in the beam splitting path. The signal energy obtained by the photodetector collecting the reflected light is acquired again, and the signal energy acquired at this time is the second signal energy.

[0045] It should be noted that when the measuring device is in the second operating condition, the light field area on the stage is a dark field. A dark field means that the position of the light source is such that most of the light is not reflected to the camera, and only the light illuminating a specific part of the object being measured is reflected to the camera.

[0046] Step 103: Determine the first light intensity distribution information based on the first signal energy, and determine the second light intensity distribution information based on the second signal energy.

[0047] Optionally, the first light intensity distribution information can be determined by determining the light intensity signal output by the light source and the reflection Jones matrix of the device under test, and by performing formula calculations in conjunction with the first signal energy; the second light intensity distribution information can be determined by determining the light intensity signal output by the light source and the reflection Jones matrix of the device under test, and by performing formula calculations in conjunction with the second signal energy.

[0048] Step 104: Obtain the surface stress information of the component under test based on the first light intensity distribution information and the second light intensity distribution information.

[0049] Optionally, the refractive index of the element under test after being subjected to stress is measured. Based on the refractive index, the first light intensity distribution information, and the second light intensity distribution information, an expression formula containing isoclins and arithmetic lines is calculated. By calculating the expression formula, the isoclins and arithmetic lines of the element under test are calculated. Based on the isoclins and arithmetic lines of the element under test, combined with the photoelastic constant of the element under test and the sample thickness, the surface stress information of the element under test is calculated.

[0050] According to the method for measuring the surface stress of an optical element according to the embodiments of this application, by acquiring the first signal energy and the second signal energy output by the photodetector, it is ensured that the stress information caused by the change in the surface shape of the element under test is not introduced when calculating the surface stress of the element under test. This allows the measurement process to obtain relevant data more directly, reduces the number of experiments, increases the measurement efficiency, and avoids the angle error caused by multiple measurements. By determining the first light intensity distribution information and the second light intensity distribution information, the surface stress of the element under test is measured, ensuring the accuracy of the measurement results. Furthermore, the measurement process has low environmental requirements, a simple optical path structure and data recording process, and low operational difficulty.

[0051] It should be noted that the initial light intensity distribution information can be determined by obtaining the reflection Jones matrix of the element under test, such as... Figure 2 As shown, Figure 2 A flowchart of another method for measuring surface stress of an optical element provided in this application embodiment, the method comprising the following steps:

[0052] Step 201: Obtain the first signal energy output by the photodetector; the first signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the component under test on the stage when the measuring device is in the first working condition.

[0053] In the embodiments of this application, step 201 can be implemented in any of the ways described in the various embodiments of this application. The embodiments of this application do not limit this, nor will they be described in detail.

[0054] Step 202: Obtain the second signal energy output by the photodetector; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test when the measuring device is in the second operating condition.

[0055] In the embodiments of this application, step 202 can be implemented in any of the ways described in the various embodiments of this application. The embodiments of this application do not limit this, nor will they be described in detail.

[0056] Step 203: Obtain the light intensity information output by the light source and obtain the reflection Jones matrix of the component under test.

[0057] It should be noted that a spatial rectangular coordinate system is established, where the direction of the optical axis of the splitting beam is the z-axis. An xy coordinate system is established in the plane perpendicular to the optical axis of the splitting beam, with the x-axis being the horizontal coordinate axis and the y-axis being the coordinate axis perpendicular to the z-axis. The light source is turned on, and the component under test (DUT) is placed on the stage, ensuring that the DUT is located within the optical path. The light output from the light source is... Among them, A s Let A be the amplitude of the light output from the light source in the S direction. p Let S be the amplitude of the light output from the light source in the P direction, and let S be perpendicular to the P direction in the plane; the reflection Jones matrix of the element under test is:

[0058]

[0059]

[0060]

[0061] Where n is the refractive index of the material in contact with the element in the xy plane, n o n e These are the refractive indices (n) of the element under test after being subjected to stress. o n is the first refractive index. e (where φ is the second refractive index), and φ is the refractive index n. e The azimuth angle in the x-direction, J is the Jones matrix, r ss r ps r sp and r pp is an element in the Jones matrix.

[0062] Step 204: Determine the first light intensity distribution information based on the light intensity information output by the light source, the reflection Jones matrix of the device under test, and the first signal energy.

[0063] In one implementation, the first light intensity distribution information is calculated based on the light intensity information output by the light source, the reflection Jones matrix of the device under test, and the first signal energy, according to the following formula (2), where formula (2) is expressed as follows:

[0064] I1=(A S r ss ) 2 (2).

[0065] According to the reflection Jones matrix of the component under test, we know that:

[0066]

[0067] Substituting formula (3) into formula (2) yields the following formula:

[0068]

[0069] Wherein, I1 represents the first light intensity distribution information.

[0070] Step 205: Determine the second light intensity distribution information based on the light intensity information output by the light source, the reflection Jones matrix of the device under test, and the second signal energy.

[0071] In one implementation, the second light intensity distribution information is calculated using the following formula (5) based on the light intensity information output by the light source, the reflection Jones matrix of the device under test, and the second signal energy, where formula (5) is expressed as follows:

[0072] I2=(A S r ps ) 2 (5)

[0073] According to the reflection Jones matrix of the component under test, we know that:

[0074]

[0075] Substituting formula (6) into formula (5) yields the following formula:

[0076]

[0077] Among them, I2 represents the second light intensity distribution information.

[0078] Step 206: Obtain the surface stress information of the component under test based on the first light intensity distribution information and the second light intensity distribution information.

[0079] In the embodiments of this application, step 206 can be implemented in any of the ways described in the various embodiments of this application. The embodiments of this application do not limit this, nor will they be described in detail.

[0080] The method for measuring the surface stress of an optical element according to the embodiments of this application measures the surface stress of the element under test by determining the first light intensity distribution information and the second light intensity distribution information, ensuring the accuracy of the measurement results, and without causing new changes to the surface shape of the element under test. It has low environmental requirements, does not require optical waveguide devices such as prisms to couple the incident light, and only needs to record the reflected light intensity twice to obtain the surface stress information, reducing the number of experiments and the amount of data that needs to be calculated, and realizing rapid and real-time measurement of surface stress.

[0081] It should be noted that surface stress information of the component under test can be obtained by acquiring the isocliptels and isoclinals of the component, such as... Figure 3 As shown, Figure 3 A flowchart of another method for measuring surface stress of an optical element provided in this application embodiment, the method comprising the following steps:

[0082] Step 301: Obtain the first signal energy output by the photodetector; the first signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the component under test on the stage when the measuring device is in the first working condition.

[0083] In the embodiments of this application, step 301 can be implemented in any of the ways described in the various embodiments of this application. The embodiments of this application do not limit this, nor will they be described in detail.

[0084] Step 302: Obtain the second signal energy output by the photodetector; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test when the measuring device is in the second operating condition.

[0085] In the embodiments of this application, step 302 can be implemented in any of the ways described in the various embodiments of this application. The embodiments of this application do not limit this, nor will they be described in detail.

[0086] Step 303: Determine the first light intensity distribution information based on the first signal energy, and determine the second light intensity distribution information based on the second signal energy.

[0087] In the embodiments of this application, step 303 can be implemented in any of the embodiments of this application. The embodiments of this application do not limit this and will not be described in detail.

[0088] Step 304: Determine the first and second refractive indices of the element under test after it is subjected to stress.

[0089] Wherein, the first refractive index n o The ordinary refractive index conforms to the conventional quantitative refractive index of materials; the second refractive index n e It is an unusual refractive index, which does not conform to the conventional quantitative understanding of material refraction.

[0090] Step 305, based on the first refractive index n o Second refractive index n e Determine the target refractive index.

[0091] It should be noted that when the first refractive index n o Second refractive index n e Satisfy |n e -n o When |≤0.1, the target refractive index n' can be determined, and n' takes the maximum value of n. o ,n e ); whereby, by adjusting the component under test, the adjustment of |n| can be achieved. e -n o Adjustment of the results.

[0092] Step 306: Determine the isotropic lines and isoclinic lines of the element under test based on the first light intensity distribution information, the second light intensity distribution information, and the target refractive index.

[0093] It should be noted that, according to the first refractive index n o Second refractive index n e The target refractive index n' and the first light intensity distribution information are used to calculate the first intermediate data using formula (8), where formula (8) is expressed as follows:

[0094]

[0095] in, The lines are arithmetic progressions, φ is an isoclinal line, n' is the target refractive index, and A... s I1 represents the S component of the light intensity information output by the light source, and I1 represents the first light intensity distribution information.

[0096] It should be noted that the above formula (8) can be obtained by deriving formula (2), wherein the deriving steps of formula (2) are as follows:

[0097] Based on the reflection Jones matrix of the element under test, we can obtain:

[0098]

[0099] Substituting formula (3) into formula (2) and taking the square root of the first light intensity distribution information, we get:

[0100]

[0101] Since n is the refractive index of the material in contact with the component in the xy plane under air conditions, n = 1.

[0102] Substituting n=1 into formula (9) and transforming formula (9), we get:

[0103]

[0104] As an example, when the first refractive index n o Second refractive index n e Satisfy |n e -n o When |≤0.1, the target refractive index n' can be determined, and n' takes the maximum value of n. o ,n e In practice, the first refractive index n can be maintained by adjusting the element under test. o Second refractive index n e Satisfy |n e -n o|≤0.1, then n' and Substituting into formula (10), we get:

[0105]

[0106] By transforming formula (11), Referring to the left side of the equation, By referring to the right side of the equation, we can obtain the above formula (8):

[0107]

[0108] in, This is the first intermediate data.

[0109] It should be noted that, based on the target refractive index n' and the second light intensity distribution information, the second intermediate data is calculated using formula (12), which is expressed as follows:

[0110]

[0111] in, The lines are arithmetic progressions, φ is an isoclinal line, n' is the target refractive index, and A... s I1 represents the S component of the light intensity information output by the light source, and I2 represents the second light intensity distribution information.

[0112] It should be noted that the above formula (12) can be obtained by deriving formula (5).

[0113] The steps for deriving formula (5) are as follows:

[0114] Based on the reflection Jones matrix of the element under test, we can obtain:

[0115]

[0116] Substituting formula (13) into formula (5) and taking the square root of the second light intensity distribution information, we get:

[0117]

[0118] Since n is the refractive index of the material in contact with the component in the xy plane under air conditions, n = 1.

[0119] Substituting n=1 into formula (14) and transforming formula (14), we get:

[0120]

[0121] As an example, when the first refractive index n o Second refractive index n e Satisfy |ne -n o When |≤0.1, the target refractive index n' can be determined, and n' takes the maximum value of n. o ,n e In practice, the first refractive index n can be maintained by adjusting the element under test. o Second refractive index n e Satisfy |n e -n o |≤0.1, then n' and Substituting into formula (15), we get:

[0122]

[0123] By transforming formula (16), Referring to the left side of the equation, By referring to the right side of the equation, we can obtain:

[0124]

[0125] in, This is the second intermediate data.

[0126] Optionally, the ratio tan²φ between the first intermediate data and the second intermediate data can be calculated, and this ratio tan²φ can be used to determine the isoclimate of the component under test; alternatively, the first and second intermediate data can be used to calculate and determine the arithmetic progressions of the component under test.

[0127] In one implementation, the formula for calculating tan2φ can be the ratio of the second intermediate data to the first intermediate data, expressed as formula (17) below. After determining the result of tan2φ, the value of the isoclinal φ can be determined.

[0128] The formula for calculating the isometric line is: the square of the first intermediate data plus the square of the second intermediate data, and the square root of the result is applied. The formula is expressed as follows (19).

[0129]

[0130]

[0131] It should be noted that, given the result of tan2φ, the value of the isoclin φ can be calculated using trigonometric functions.

[0132] It should be noted that by substituting the first and second intermediate data into formula (17), we can obtain the result;

[0133]

[0134] It should be noted that if the bias direction is not changed, let As = 1 and E = [1, 0]; if the bias direction is changed, As = 1 and E = [1, 0] can be achieved through pre-calibration. Pre-calibration refers to measuring surface stress without placing an object on the stage, or measuring by placing a standard part on the stage instead of an object.

[0135] Substituting As = 1 into formula (17), we get:

[0136]

[0137] Substituting the first and second intermediate data into formula (19) yields:

[0138]

[0139] Where φ is an isoclinal line. These are isoarithmic lines.

[0140] Step 307: Determine the surface stress information of the component under test based on the isotropic lines and isoclinic lines.

[0141] It should be noted that, based on the photoelastic constant of the component under test, the sample thickness, isochoric lines, and isoartic lines, the surface stress information of the component under test is calculated using formula (22), where formula (22) is expressed as follows:

[0142]

[0143] Among them, f σ denoted as the photoelastic constant of the element under test, d as the sample thickness, and Δ as the shear stress.

[0144] To achieve the above embodiments, the application also proposes a device for measuring the surface stress of optical elements.

[0145] Figure 4 A positional relationship diagram of a device for measuring surface stress of an optical element provided in an embodiment of this application, as shown in the figure. Figure 4 As shown, the device for measuring the surface stress of the optical element may include: a light source 1, a polarizer 2, a filter beam expander collimator 3, a beam splitter 4, a stage 5, an imaging lens 6, an analyzer 7, and a photodetector 8, arranged sequentially along the optical path of the light source output; wherein, the measuring device also includes a control module 9 connected to the photodetector 8.

[0146] It should be noted that the control module 9 can be a digital computer of various forms, such as a laptop computer, desktop computer, workbench, personal digital assistant, server, blade server, mainframe computer, and other suitable computers. Furthermore, the control module stores a computer program that, when executed, implements the method for measuring the surface stress of the optical element in any of the above embodiments.

[0147] In one implementation, the light source emits a beam that is then split. This split beam passes through a polarizer and a beam expander to polarize it, making it light with only a single direction. The split beam then passes through a filter, beam expander, and collimator, which filters and expands the beam, transforming it from divergent light into parallel light. Next, the split beam passes through a beam splitter, which separates the resonant absorption lines required by the beam splitter. The processed beam then illuminates the device under test (DUT) on the stage. The reflected light from the DUT is then processed by an imaging lens and a polarizer to polarize it. Finally, the reflected light is imaged on a photodetector, which detects the signal energy of the reflected light.

[0148] In this embodiment, the control module 9 can acquire the first signal energy output by the photodetector 8; the first signal energy is the signal energy obtained by the photodetector 8 collecting the reflected light generated by the component under test on the stage when the measuring device is in a first operating condition; the control module 9 can also acquire the second signal energy output by the photodetector 8; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the component under test when the measuring device is in a second operating condition. The control module 9 can determine the first light intensity distribution information based on the first signal energy, determine the second light intensity distribution information based on the second signal energy, and acquire the surface stress information of the component under test based on the first light intensity distribution information and the second light intensity distribution information.

[0149] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0150] According to the embodiment of the present application, the optical element surface stress measuring device obtains the first signal energy and the second signal energy output by the photodetector, ensuring that stress information caused by changes in the surface shape of the element under test is not introduced when calculating the surface stress of the element under test. This allows the measurement process to obtain relevant data more directly, reduces the number of experiments, increases measurement efficiency, and avoids angle errors caused by multiple measurements. By determining the first light intensity distribution information and the second light intensity distribution information, the surface stress of the element under test is measured, ensuring the accuracy of the measurement results. Furthermore, the measurement process has low environmental requirements, a simple optical path structure and data recording process, and low operational difficulty.

[0151] According to embodiments of this application, this application also provides a computer device and a readable storage medium.

[0152] like Figure 5 The diagram shown is a block diagram of a computer apparatus for measuring the surface stress of an optical element according to an embodiment of this application. The computer apparatus is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The computer apparatus may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present application described and / or claimed herein.

[0153] like Figure 5 As shown, the computer device includes one or more processors 501, memory 502, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components are interconnected via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In other embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 5 Take a processor 501 as an example.

[0154] The memory 502 is the non-transitory computer-readable storage medium provided in this application. The memory stores instructions executable by at least one processor to cause the at least one processor to perform the method for measuring the surface stress of an optical element provided in this application. The non-transitory computer-readable storage medium of this application stores computer instructions for causing a computer to perform the method for measuring the surface stress of an optical element provided in this application.

[0155] The memory 502, as a non-transient computer-readable storage medium, can be used to store non-transient software programs, non-transient computer-executable programs, and modules, such as the program instructions / modules corresponding to the method for measuring the surface stress of optical elements in the embodiments of this application. The processor 501 executes various functional applications and data processing of the server by running the non-transient software programs, instructions, and modules stored in the memory 502, thereby realizing the method for measuring the surface stress of optical elements in the above method embodiments.

[0156] Memory 502 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device for live video processing. Furthermore, memory 502 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory 502 may optionally include memory remotely located relative to processor 501, and this remote memory may be connected to the computer device for live video processing via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0157] The computer device for measuring the surface stress of optical elements may further include an input device 503 and an output device 504. The processor 501, memory 502, input device 503, and output device 504 can be connected via a bus or other means. Figure 5 Taking the example of a connection between China and Israel via a bus.

[0158] Input device 503 can receive input numerical or character information, as well as generate key signal inputs related to user settings and function control of the computer equipment for live video processing, such as touch screens, keypads, mice, trackpads, touchpads, joysticks, one or more mouse buttons, trackballs, joysticks, etc. Output device 504 may include display devices, auxiliary lighting devices (e.g., LEDs), and haptic feedback devices (e.g., vibration motors). The display device may include, but is not limited to, liquid crystal displays (LCDs), light-emitting diode (LED) displays, and plasma displays. In some embodiments, the display device may be a touch screen.

[0159] Various implementations of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, application-specific integrated circuits (ASICs), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include: implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transferring data and instructions to the storage system, the at least one input device, and the at least one output device.

[0160] These computational programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term “machine-readable signal” refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0161] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0162] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), the Internet, and blockchain networks.

[0163] Computer systems can include clients and servers. Clients and servers are generally geographically separated and typically interact via communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. A server can be a cloud server, also known as a cloud computing server or cloud host, a hosting product within the cloud computing service ecosystem, addressing the shortcomings of traditional physical hosts and VPS (Virtual Private Server, or simply "VPS") services, such as high management difficulty and weak business scalability. Servers can also be servers for distributed systems or servers incorporating blockchain technology.

[0164] According to the technical solution of this application embodiment, by acquiring the first signal energy and the second signal energy output by the photodetector, it is ensured that stress information caused by changes in the surface shape of the component under test is not introduced when calculating the surface stress of the component under test. This allows the measurement process to obtain relevant data more directly, reduces the number of experiments, increases measurement efficiency, and avoids angle errors caused by multiple measurements. By determining the first light intensity distribution information and the second light intensity distribution information, the surface stress of the component under test is measured, ensuring the accuracy of the measurement results. Furthermore, the measurement process has low environmental requirements, a simple optical path structure and data recording process, and low operational difficulty.

[0165] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for measuring surface stress of an optical element, characterized in that, The measuring device for implementing the measurement method is a device designed based on the Fresnel reflection formula for anisotropic media. The measuring device includes a light source, and along the optical path direction output from the light source are, in sequence, a polarizer, a filter beam expander collimator, a beam splitter, a stage, an imaging lens, an analyzer, and a photodetector. The measurement method includes: The first signal energy output by the photodetector is obtained; the first signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the component under test on the stage when the measuring device is in the first operating condition. The second signal energy output by the photodetector is obtained; the second signal energy is the signal energy obtained by the photodetector collecting the reflected light generated by the element under test when the measuring device is in the second operating condition; wherein, when the measuring device is in the first operating condition, the light field region on the stage is a bright field, and when the measuring device is in the second operating condition, the light field region on the stage is a dark field. The first light intensity distribution information is determined based on the first signal energy, and the second light intensity distribution information is determined based on the second signal energy; Determine the first and second refractive indices of the element under test after it is subjected to stress. According to the first refractive index and the second refractive index Determine the target refractive index; Based on the first light intensity distribution information, the second light intensity distribution information, and the target refractive index, the isotropic lines and isoclinic lines of the element under test are determined; The surface stress information of the element under test is determined based on the isotropic lines and isoclinic lines. The formula for calculating the arithmetic contour lines is as follows: ； The formula for calculating the isoclin is as follows: ； in, The isometry lines are... ; The isoclinometer is mentioned above. This refers to the first light intensity distribution information; This refers to the second light intensity distribution information; The target refractive index, .

2. The method according to claim 1, characterized in that, The step of determining the first light intensity distribution information based on the first signal energy and determining the second light intensity distribution information based on the second signal energy includes: Obtain the light intensity information output by the light source, and obtain the reflection Jones matrix of the element under test; The first light intensity distribution information is determined based on the light intensity information output by the light source, the reflection Jones matrix of the element under test, and the first signal energy. The second light intensity distribution information is determined based on the light intensity information output by the light source, the reflection Jones matrix of the element under test, and the second signal energy.

3. The method according to any one of claims 1 to 2, characterized in that, The measuring device is in the first operating condition, including: The polarization direction of the polarization plane of the polarizer is 0° in the beam splitting path and the x-direction, and the polarization direction of the analyzer is 0° in the beam splitting path and the x-direction; The optical axis of the beam splitter is z-direction. An experimental reference xy coordinate system is established in a plane perpendicular to the optical axis, wherein the x-direction in the xy coordinate system is horizontal and the y-direction is perpendicular to the x-direction in the plane.

4. The method according to claim 3, characterized in that, The measuring device is in the second operating condition, including: The polarization direction of the polarization plane of the polarizer is 0° in the beam splitting path and the x-direction, and the polarization direction of the analyzer is 90° in the beam splitting path and the x-direction.

5. A device for measuring surface stress of an optical element, characterized in that, The measuring device includes a light source, and along the optical path direction output from the light source, sequentially comprises a polarizer, a filter, a beam expander, a collimator, a beam splitter, a stage, an imaging lens, an analyzer, and a photodetector; wherein, the measuring device further includes: A control module connected to the photodetector, the control module storing a computer program, which, when executed, implements the method as described in any one of claims 1 to 4.

6. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the method as described in any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 4.

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