Method for detecting light transmittance and hardness of nanocrystalline glass in an integrated manner

Abstract

The application discloses a light transmittance and hardness integrated detection method based on nano-cristalline glass, and belongs to the technical field of nano-cristalline glass detection. The method comprises the following steps: applying a dynamic load to the surface of a nano-cristalline glass sample, and synchronously collecting stress response data and transmission light intensity change data under the dynamic load; according to the corresponding relationship between the stress response data and the transmission light intensity change data in time sequence, a load-transmission synchronous response curve is constructed; the light transmittance characteristic value under different stress states is extracted from the curve, and the hardness characteristic value is determined according to the loading process of the dynamic load and the stress response data; and the light transmittance characteristic value and the hardness characteristic value are input into a preset quality discrimination model, and an integrated detection result is output. The method realizes synchronous acquisition and fusion discrimination of the light transmittance and hardness information of the nano-cristalline glass in the same loading process.

Description

Technical Field

[0001] This invention relates to the field of nanocrystalline glass testing technology, specifically to an integrated testing method for transmittance and hardness of nanocrystalline glass. Background Technology

[0002] Nanocrystalline glass is widely used in electronic displays, optical windows, and other fields. Its transmittance and hardness are key indicators determining product quality and service performance. Current technology for quality inspection of nanocrystalline glass typically employs a step-by-step, independent testing approach: transmittance is measured under static conditions using a spectrophotometer or integrating sphere, and hardness data is then obtained separately using a microhardness tester or nanoindentation apparatus. This separate testing method cannot obtain the synchronous correlation between transmittance and hardness under dynamic loads, making it difficult to reflect the synergistic evolution of optical and mechanical properties during actual loading. For applications requiring assessment of overall product reliability, such as the ability of cover glass to maintain visual transparency under pressure, isolated transmittance and hardness values ​​alone cannot provide an accurate quality judgment. Furthermore, step-by-step independent testing requires changing equipment and repeatedly clamping samples, resulting in a lengthy and inefficient testing process, and is prone to data inconsistencies due to differences in sample conditions.

[0003] Nanocrystalline glass often withstands dynamic contact loads in practical applications. The stress distribution between its internal crystalline and glassy phases alters its light scattering and absorption characteristics, causing its light transmittance to change continuously with stress state. A key challenge is how to simultaneously capture the real-time changes in stress response and transmitted light intensity during a single dynamic loading process, and extract characteristic parameters that characterize the material's optical-mechanical coupling behavior within a unified temporal framework. This would enable the integrated automatic determination of transmittance and hardness. Summary of the Invention

[0004] This paper presents an integrated method for detecting the transmittance and hardness of nanocrystalline glass. It can simultaneously collect stress response and transmitted light intensity change information during a single dynamic loading process, construct a load-transmittance synchronous response curve that reflects the optical-mechanical coupling behavior of the material, and extract the characteristic values ​​of transmittance and hardness at different stress stages from the same loading process. Through model fusion and discrimination, it can achieve rapid and accurate integrated detection of the quality of nanocrystalline glass.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides an integrated testing method for transmittance and hardness based on nanocrystalline glass, comprising the following steps: applying a dynamic load to the surface of a nanocrystalline glass sample, and simultaneously acquiring stress response data and transmitted light intensity change data of the nanocrystalline glass sample under the dynamic load; constructing a load-transmittance synchronous response curve of the nanocrystalline glass sample based on the temporal correspondence between the stress response data and the transmitted light intensity change data; extracting transmittance characteristic values ​​of the nanocrystalline glass sample under different stress states from the load-transmittance synchronous response curve, and simultaneously determining the hardness characteristic value of the nanocrystalline glass sample based on the loading history of the dynamic load and the stress response data; inputting the transmittance characteristic value and the hardness characteristic value into a preset quality discrimination model, and outputting the integrated testing result of the nanocrystalline glass sample. This method obtains optical and mechanical performance indicators simultaneously in a single testing process, avoiding efficiency losses and inconsistencies in sample state caused by separate testing, and making the test results closer to the actual service performance of the glass.

[0006] In a preferred embodiment of the present invention, in the step of applying a dynamic load to the surface of a nanocrystalline glass sample and simultaneously acquiring data, the nanocrystalline glass sample is fixed on a stage, with the tip of the indenter vertically aligned with the surface area to be tested. The indenter is controlled to press into the sample surface at a preset loading rate, and the real-time reaction force received by the indenter is continuously recorded by a force sensor as the stress response data. Simultaneously, incident light emitted from a light source is vertically irradiated onto the pressing position, and a light intensity detector located on the back of the sample continuously records the real-time transmitted light intensity after passing through the sample as the transmitted light intensity change data. This coaxial and synchronous optical path and mechanical loading layout ensures a one-to-one correspondence between the load and the transmitted light signal in time and space, fundamentally improving the accuracy of data coupling.

[0007] Preferably, when constructing the load-transmittance synchronous response curve, the real-time reaction force and the real-time transmitted light intensity are aligned along the same sampling time axis. A continuous trajectory is plotted from the start to the end of the pressing process, with the reaction force value as the abscissa and the transmitted light intensity value as the ordinate, to obtain the curve. This curve visually demonstrates the dynamic evolution of transmittance performance with increasing load, providing a complete visualization basis for subsequent feature extraction.

[0008] In a preferred scheme for extracting transmittance feature values, the boundary point between the elastic deformation stage and the plastic deformation stage is identified on the load-transmittance synchronous response curve. The abscissa corresponding to this boundary point is taken as the yield load value. The slope of the curve within the range where the abscissa increases from zero to the yield load value is extracted as the elastic transmittance response rate, used to evaluate the sensitivity of the glass's transmittance performance to force within the elastic load range. The average ordinate of the stable segment after the abscissa exceeds the yield load value is extracted as the plastic transmittance retention rate, used to reflect the glass's ability to maintain high transmittance after entering plastic deformation. The elastic transmittance response rate and the plastic transmittance retention rate together constitute transmittance feature values ​​that can characterize the optical stability of the glass at different damage stages. The boundary point can be identified by using the position where the first derivative of the curve first abruptly changes, without human intervention, ensuring the objectivity and repeatability of feature extraction.

[0009] In a preferred scheme for determining the hardness characteristic value, the peak load corresponding to the moment the indenter reaches its maximum indentation depth is read from the real-time reaction force; the contact projection area between the indenter and the sample is calculated using the geometric parameters of the indenter and the maximum indentation depth; the peak load is divided by the contact projection area to obtain the indentation hardness value of the nanocrystalline glass sample. This hardness value reflects the material's overall ability to resist local indentation deformation and is obtained under the same loading history as the light transmittance characteristic value, giving the two an inherent physical correlation.

[0010] As a technical solution of this invention, the quality discrimination model is constructed using a support vector machine, with its input vector set as a three-dimensional input vector composed of elastic light transmittance responsivity, plastic light transmittance retention rate, and indentation hardness value. The model is trained using the three-dimensional feature data of qualified and unqualified samples, and can automatically learn the optimal classification boundary between the two types of samples in high-dimensional space. During detection, the model outputs classification labels, directly determining whether a sample is qualified or unqualified, achieving transparent and objective automated discrimination and effectively reducing the subjectivity of manual interpretation.

[0011] In the preferred loading control method, the corresponding loading rate parameter is selected from the database based on the nominal thickness of the nanocrystalline glass sample. In the initial stage when the indenter begins to contact the sample surface, a first loading rate is used. Once the real-time reaction force reaches a preset threshold force, the loading rate is automatically switched to a smaller second loading rate through closed-loop feedback control, and the timing of the loading rate changes throughout the process is recorded. This segmented variable-speed loading method shortens the initial approach phase time and acquires high-resolution data at a slower rate within the depth range where substantial damage occurs, avoiding excessive damage to brittle glass from dynamic impacts and facilitating the capture of subtle force-optical response characteristics.

[0012] In the preferred scheme for acquiring transmitted light intensity, the light source and light intensity detector are activated before the pressure head is pressed in, and the initial transmitted light intensity under no-load conditions is recorded as the reference light intensity value. During the pressing process, the transmitted light intensity is continuously acquired at a preset sampling frequency. The relative change in transmitted light intensity is obtained by subtracting the reference light intensity value from the transmitted light intensity at each sampling moment, and then superimposed with the reference light intensity value to obtain the real-time transmitted light intensity output at that moment. This differential reference correction method eliminates the influence of ambient light drift and light source fluctuations on the measurement results, significantly improving the signal-to-noise ratio and stability of the transmitted light intensity data.

[0013] To improve the robustness of the model's discrimination, the transmittance and hardness feature values ​​are normalized before being input into the quality discrimination model. The transmittance and hardness feature value sets of multiple samples from the same batch are obtained, and their respective means and standard deviations are calculated. The original feature value of each sample is subtracted from the corresponding mean and then divided by the standard deviation to obtain the normalized feature value, which is then substituted into the model. Normalization eliminates the differences in numerical distribution caused by minor process variations between batches, ensuring a unified discrimination standard and enhancing the comparability of test results across batches.

[0014] In a preferred embodiment of the present invention, after outputting the integrated test results, a unique sample identification code is generated for each tested nanocrystalline glass sample. The sample identification code, the integrated test results, and the load-transmittance synchronous response curve are jointly stored in the test database, and a data record is established in the database using the sample identification code as the primary key. The test results and the complete synchronous response curve can be retrieved at any time through the sample identification code, achieving traceability of the entire lifecycle test data for a single product, and providing detailed process data support for process adjustment and failure analysis.

[0015] The technical effects and advantages provided by the present invention in the above technical solution are as follows: By applying dynamic loads to nanocrystalline glass samples and simultaneously acquiring stress response data and transmitted light intensity variation data, a strict temporal correspondence is established between the reaction force and transmitted light intensity at any point during the indentation process, thereby constructing a load-transmittance synchronous response curve. This synchronous acquisition scheme integrates the transmittance and hardness information obtained independently in steps in traditional separate testing into a single loading time frame, avoiding data mismatches caused by multiple clamping operations and differences in testing conditions between different devices. A single test can completely record the continuous change trajectory of the optical response of the material from elastic loading to plastic deformation, providing direct evidence for revealing the evolution of the transmittance performance of nanocrystalline glass under real stress conditions.

[0016] Transmittance feature values, including elastic transmittance responsivity and plastic transmittance retention, are extracted from the load-transmittance synchronous response curves during both the elastic and plastic deformation stages. Simultaneously, indentation hardness values ​​are determined based on the dynamic load history and stress response data. The elastic transmittance responsivity, plastic transmittance retention, and hardness feature values ​​are combined to form a three-dimensional input vector, which is then fed into a quality discrimination model based on a support vector machine for integrated classification. By utilizing the sensitivity of transmittance to load changes in the elastic stage and the stable retention level of transmittance in the plastic stage, along with the material's resistance to local indentation hardness, the discrimination model comprehensively utilizes the coupling characteristics of optical and mechanical properties under multiple strain states. Compared to classification methods relying solely on a single hardness index or static transmittance index, this approach provides a clearer boundary for judging the batch quality of nanocrystalline glass, effectively distinguishing deviations in optical-mechanical response patterns caused by microstructural differences, and improving the accuracy of separating qualified and unqualified products. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0018] Figure 1 This is a flowchart of an integrated testing method for transmittance and hardness based on nanocrystalline glass. Figure 2 This is a schematic diagram of a synchronous load-transmittance response testing device for nanocrystalline glass; Figure 3 This is a flowchart of the integrated detection method for nanocrystalline glass; Figure 4 This is a flowchart of the nanocrystalline glass sample indentation test method; Figure 5 This is the load-transmittance synchronous response curve of the nanocrystalline glass sample; Figure 6 It is the curve showing the relationship between the real-time reaction force and the threshold force during the loading process; Figure 7 It is a frequency distribution diagram of normalized transmittance characteristic values ​​and hardness characteristic values. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0020] See Figure 1 This invention provides an integrated method for detecting the transmittance and hardness of a nanocrystalline glass sample. The method applies a dynamic load to the surface of the nanocrystalline glass sample and simultaneously collects stress response data and transmitted light intensity variation data under the dynamic load. Based on the temporal correspondence between the stress response data and transmitted light intensity variation data, a load-transmittance synchronous response curve for the nanocrystalline glass sample is constructed. Transmittance characteristic values ​​of the nanocrystalline glass sample under different stress states are extracted from the load-transmittance synchronous response curve. Simultaneously, the hardness characteristic value of the nanocrystalline glass sample is determined based on the loading history of the dynamic load and the stress response data. The transmittance and hardness characteristic values ​​are input into a pre-set quality discrimination model, outputting the integrated detection result of the nanocrystalline glass sample.

[0021] Example 1: In specific implementation, please refer to Figure 2 The nanocrystalline glass sample is fixed on a stage equipped with a vacuum adsorption chamber. The negative pressure generated by a vacuum pump adsorbs the lower surface of the nanocrystalline glass sample onto the stage surface, keeping the sample stationary relative to the stage during the test. The indenter position is adjusted so that its tip is perpendicularly aligned with the test surface area of ​​the nanocrystalline glass sample, with a perpendicularity deviation controlled within 0.1° to ensure that the indentation direction coincides with the normal direction of the nanocrystalline glass sample surface.

[0022] The pressure head is pressed into the surface of the nanocrystalline glass sample at a preset loading rate. The pressure head is driven by a piezoelectric drive unit, and the loading rate is achieved by setting the slope of the driving voltage change of the piezoelectric drive unit. During the pressing process, a strain gauge force sensor continuously records the real-time reaction force on the pressure head, which is installed on the connecting rod between the pressure head and the piezoelectric drive unit. The force sensor outputs the real-time reaction force value at a first sampling frequency, and the real-time reaction force value is used as stress response data.

[0023] Simultaneously with the indenter's insertion, incident light emitted from the light source is perpendicularly irradiated onto the indentation position of the indenter. The light source is a 532nm laser. The incident light emitted from the laser is collimated by a collimating lens to form parallel light, which is perpendicularly incident on the test surface area of ​​the nanocrystalline glass sample. The center of the light spot coincides with the projection point of the indenter tip onto the surface of the nanocrystalline glass sample. A light intensity detector, a silicon photodiode, is positioned on the back of the nanocrystalline glass sample. The photosensitive surface of the silicon photodiode faces the incident light spot. The light intensity detector continuously records the real-time transmitted light intensity after passing through the nanocrystalline glass sample. The light intensity detector outputs the real-time transmitted light intensity value at a second sampling frequency, which serves as the transmitted light intensity change data. The first and second sampling frequencies are set to the same value and triggered by the same clock source to align the real-time reaction force value with the real-time transmitted light intensity value on the sampling time axis.

[0024] After the pressing process is completed and the indenter movement stops, a time series containing multiple sampling moments is obtained. Each sampling moment corresponds to a real-time reaction force value and a real-time transmitted light intensity value. The real-time reaction force value and the real-time transmitted light intensity value are aligned along the same sampling time axis, that is, a pairing relationship between the reaction force value and the transmitted light intensity value at the same time point is established using the sampling time point as an index. With the reaction force value as the abscissa and the transmitted light intensity value as the ordinate, the data point corresponding to the start of pressing is taken as the starting point, and the data point corresponding to the end of pressing is taken as the ending point. The coordinate points determined by the reaction force value and the transmitted light intensity value at adjacent sampling moments are connected sequentially in chronological order to form a continuous trajectory from the start to the end of pressing. This continuous trajectory is the load-transmission synchronous response curve.

[0025] See Figure 5 The load-transmission synchronous response curve, with real-time reaction force (mN, x-axis) as the x-axis and real-time transmitted light intensity (mW / cm², y-axis) as the y-axis, shows the variation of transmitted light intensity of the nanocrystalline glass sample under dynamic loading. Starting from the lower left corner, the real-time reaction force gradually increases from approximately 0 mN to nearly 200 mN, while the real-time transmitted light intensity gradually increases from approximately 10.0 mW / cm² to approximately 11.6 mW / cm².

[0026] The curves exhibit two distinct phases of change: The first phase, within the range of 0 to approximately 80 millinewtons on the horizontal axis, shows a rapid, linear increase in transmitted light intensity with the reaction force. The curve has a steep slope and minimal fluctuations, indicating that this is the elastic deformation phase, where the transmitted light intensity is sensitive and stable to changes in the reaction force. The second phase, within the range of approximately 80 to 200 millinewtons on the horizontal axis, shows a more stable transmitted light intensity. The curve exhibits smaller fluctuations and no significant upward trend, reflecting that the sample has entered the plastic deformation phase. The transmitted light intensity remains at a high level, and the changes become more gradual. The point approximately 80 millinewtons on the horizontal axis marks the boundary between the elastic and plastic deformation phases, i.e., the yield load. The slope of the linear fit from the curve's starting point to the yield load corresponds to the elastic transmittance, reflecting the change in transmitted light intensity caused by a unit change in reaction force. The stable region after the yield load (approximately...) The average transmitted light intensity within the range of approximately 96 millinewtons to the maximum reaction force of 200 millinewtons is the plastic transmittance retention rate, which represents the level of maintenance of transmitted light intensity of the sample during the plastic deformation stage.

[0027] The load-transmittance synchronous response curve is a continuous trajectory formed by aligning and connecting the data from the force sensor and light intensity detector synchronously in Example 1, and truly reflects the coordinated change of load and transmittance performance of the nanocrystalline glass sample during the loading process.

[0028] Example 2: In specific implementation, please refer to Figure 3 The process of extracting the transmittance characteristic values ​​of nanocrystalline glass samples under different stress states from the load-transmittance synchronous response curve is as follows.

[0029] The first derivative of the load-transmission synchronous response curve is calculated to obtain the first derivative value corresponding to each abscissa position on the curve. The first derivative is calculated using the central difference method, by locally fitting k adjacent data points on the load-transmission synchronous response curve and then obtaining the slope, where k is set to 5. At each abscissa position, the calculated first derivative reflects the rate of change of transmitted light intensity with reaction force at that position. Starting from the starting point of the load-transmission synchronous response curve, the change in the first derivative is compared point by point along the direction of increasing abscissa. When the absolute value of the difference between the first derivatives of two adjacent abscissa positions first exceeds the preset derivative mutation threshold, the next abscissa position is determined as the boundary between the elastic deformation stage and the plastic deformation stage. The derivative mutation threshold is set to three times the standard deviation of the first derivative in the stable segment in the middle of the load-transmission synchronous response curve. The stable segment in the middle of the load-transmission synchronous response curve refers to the section where the abscissa range is between 40% and 60% of the maximum abscissa value. After determining the boundary point between the elastic deformation stage and the plastic deformation stage, the abscissa corresponding to the boundary point is taken as the yield load value, denoted as . .

[0030] Extract the horizontal axis from the load-transmission synchronous response curve, increasing it from zero to the yield load value. For all data points within this segment, a linear regression fitting was performed using the least squares method. The slope of the fitted line is the elastic light transmittance. The elastic light transmittance reflects the change in transmitted light intensity caused by a unit change in reaction force during the elastic deformation stage.

[0031] Extract the horizontal axis exceeding the yield load value from the load-transmission synchronous response curve. All data points within the subsequent stable interval, where the x-axis range is from... The range between the maximum x-axis value and the maximum x-axis value is calculated. The average y-axis value of all data points within this stable range is the plastic transmittance retention rate. The plastic transmittance retention rate reflects the level of transmitted light intensity maintained by the nanocrystalline glass sample during the plastic deformation stage. The elastic transmittance response rate and the plastic transmittance retention rate are used together as the transmittance characteristic value.

[0032] In determining the hardness characteristic value of the nanocrystalline glass sample based on the loading history and stress response data of the dynamic load, all sampled values ​​of the real-time reaction force are read from the stress response data. The magnitudes of all sampled values ​​are compared, and the maximum value is obtained. The sampling time corresponding to this maximum value is the moment when the indenter reaches the maximum indentation depth. This maximum value is the peak load, denoted as . The real-time displacement of the indenter during the pressing process is recorded by a displacement sensor installed inside the piezoelectric drive unit. The sensor outputs real-time displacement values ​​at the same sampling frequency as the force sensor, and the peak load is read from these real-time displacement values. The displacement value at the same sampling time is the maximum indentation depth, denoted as . .

[0033] The indenter has a Vickers indenter geometry, with a diamond square pyramid tip and a face-to-face angle of 136°. The indenter's geometric parameters and maximum indentation depth are then considered. Calculate the projected contact area between the indenter and the nanocrystalline glass sample. The calculation formula is:

[0034] in, This represents the contact projection area, expressed in square micrometers. The maximum indentation depth is expressed in micrometers; 24.5 is the Vickers indenter geometry coefficient, which is derived from the geometric relationship of a 136° angle between the two sides of the Vickers indenter. When using a regular square pyramid indenter with a 136° angle between the two sides, the proportionality coefficient between the contact projected area and the square of the indentation depth is constant at 24.5.

[0035] peak load Divide by the contact projected area The indentation hardness value of the nanocrystalline glass sample was obtained, and the indentation hardness value was used as the hardness characteristic value.

[0036] In the process of inputting transmittance and hardness feature values ​​into a pre-set quality discrimination model and outputting integrated detection results for nanocrystalline glass samples, the elastic transmittance response rate, plastic transmittance retention rate, and indentation hardness value are combined into a three-dimensional input vector. The elastic transmittance response rate serves as the first dimension of the three-dimensional input vector, the plastic transmittance retention rate as the second dimension, and the indentation hardness value as the third dimension.

[0037] The 3D input vector is fed into a pre-trained quality discrimination model. The quality discrimination model is built upon a support vector machine (SVM), which employs a radial basis function (RBF) kernel. The expression for the RBF kernel is: In the formula This represents the three-dimensional input vector to be classified. This represents the i-th support vector. The width parameter of the radial basis kernel function. The value is 0.5. express and The Euclidean distance between them. The decision function of the support vector machine is... In the formula This represents the total number of support vectors. Let the Lagrange multiplier corresponding to the i-th support vector be denoted as . This represents the category label corresponding to the i-th support vector. , This represents the bias term. The training samples for the support vector machine contain the 3D input vectors of qualified and unqualified nanocrystalline glass samples. The class label for qualified nanocrystalline glass samples is +1, and the class label for unqualified samples is -1. During training, the Lagrange multipliers are solved using the sequential minimum optimization algorithm. and bias terms The optimal value, the convergence tolerance of the sequence minimum optimization algorithm is set to . The maximum number of iterations is set to 10,000. Obtain the classification labels output by the quality discrimination model, when the decision function... When the value is greater than 0, the output classification label is +1, and the nanocrystalline glass sample is judged to be a qualified product; when the decision function... When the value is less than or equal to 0, the output classification label is -1, and the nanocrystalline glass sample is determined to be unqualified.

[0038] Example 3: In specific implementation, please refer to Figure 4 The process of controlling the pressure head to press into the surface of the nanocrystalline glass sample at a preset loading rate is as follows.

[0039] The nominal thickness of the nanocrystalline glass sample is obtained. The nominal thickness is the value marked on the nanocrystalline glass sample at the time of manufacture, in millimeters. A loading rate parameter database is pre-built in the detection system. The database contains multiple records, each with three fields: thickness range, first loading rate parameter, and second loading rate parameter. The thickness range field stores the range to which the nominal thickness of the nanocrystalline glass sample belongs, for example, 0.3 mm to 0.5 mm, 0.5 mm to 0.8 mm, and 0.8 mm to 1.2 mm. The first loading rate parameter field stores the loading rate value used in the initial stage of the indenter within the corresponding thickness range, in millinewtons per second (mN / s). The second loading rate parameter field stores the loading rate value used after indenter switching within the corresponding thickness range, also in mN / s. Based on the nominal thickness of the nanocrystalline glass sample, the thickness range to which the nominal thickness falls is found from the loading rate parameter database, and the corresponding first and second loading rate parameters are extracted. If the nominal thickness is 0.7 mm, it falls within the thickness range of 0.5 mm to 0.8 mm. The first loading rate parameter value corresponding to this thickness range is extracted as 50 millinewtons per second, and the second loading rate parameter value is 10 millinewtons per second.

[0040] The indenter is driven by a piezoelectric drive unit, which receives an analog voltage signal from the controller. The amplitude of the analog voltage signal determines the feed rate of the indenter. The controller outputs an initial analog voltage signal, causing the indenter to move towards the surface of the nanocrystalline glass sample at a first loading rate. At the instant the tip of the indenter contacts the surface of the nanocrystalline glass sample, the real-time reaction force detected by the force sensor rises from zero. The controller continuously reads the value of the real-time reaction force at the same sampling frequency as the force sensor.

[0041] During loading, the controller compares the real-time reaction force value at each sampling moment with a preset threshold force. The preset threshold force is set to 20 millinewtons (mN). This 20 mN setting is based on the following: in the initial stage of elastic deformation of the nanocrystalline glass sample, a 20 mN reaction force ensures that the indenter tip has completely overcome the influence of microscopic unevenness on the sample surface and established a stable contact state. Simultaneously, 20 mN is far below the yield load of the nanocrystalline glass sample, preventing the sample from entering the plastic deformation stage. When the real-time reaction force reaches the preset threshold force of 20 mN, the controller automatically adjusts the amplitude of the analog voltage signal to the value corresponding to the second loading rate, switching the indenter's loading rate from the first loading rate to the second loading rate. The switching between the first and second loading rates is achieved through closed-loop feedback control, which includes a force sensor, a controller, and a piezoelectric drive unit. The force sensor feeds back the real-time reaction force value to the controller, which generates a control quantity based on the difference between the real-time reaction force value and the preset threshold force of 20 mN. When the difference equals zero, the loading rate switching is triggered. The second loading rate is lower than the first loading rate, which allows the indenter to be pressed in at a slower rate after the nanocrystalline glass sample enters the plastic deformation stage, so as to obtain more refined stress response data and transmitted light intensity change data.

[0042] Throughout the entire process from the initial contact of the indenter to the reaching of the maximum indentation depth, the controller records the real-time loading rate value at a fixed sampling interval, and stores the real-time loading rate value in association with the corresponding sampling time point to form a loading rate change sequence. The loading rate change sequence includes the time period during which the indenter operates at the first loading rate in the initial stage, and the time period during which it operates at the second loading rate after the trigger switch.

[0043] The following operations are performed during the continuous recording of real-time transmitted light intensity after passing through the nanocrystalline glass sample using a light intensity detector located on the back of the sample.

[0044] Before the pressure head is pressed in, the light source and intensity detector are activated. The light source is a 532 nm laser with an output power of 5 mW. The emitted light, after passing through a collimating lens group, forms a parallel spot with a diameter of 2 mm, which perpendicularly illuminates the test surface area of ​​the nanocrystalline glass sample. The intensity detector is a silicon photodiode with a receiving area diameter of 5 mm. After activating the light source and intensity detector, the system waits 500 milliseconds for the light source output power and the intensity detector dark current to reach a stable state. Once stable, the intensity detector continuously collects the transmitted light intensity under no-load conditions at a preset second sampling frequency, collecting 100 sampling points. The average value of the transmitted light intensity at these 100 sampling points is calculated and used as the reference intensity value, denoted as [reference value]. Reference light intensity value It reflects the intrinsic transmission characteristics of the nanocrystalline glass sample under the condition of no external force.

[0045] During the pressing process, the light intensity detector continuously collects the transmitted light intensity at a preset second sampling frequency, which is set to 1000 Hz. The transmitted light intensity collected at each sampling moment is recorded as follows: , Indicates the sampling time The corresponding original transmitted light intensity value. Calculate the value at each sampling time. The original transmitted light intensity value Compared with the reference light intensity value The difference between them is the relative change in transmitted light intensity, denoted as . The calculation expression is:

[0046] in, Indicates the sampling time The relative change in transmitted light intensity, expressed in milliwatts per square centimeter; Indicates the sampling time The raw transmitted light intensity value collected by the light intensity detector, in milliwatts per square centimeter; This represents the reference light intensity value, expressed in milliwatts per square centimeter.

[0047] Each sampling time Corresponding relative change in transmitted light intensity Superimposed reference light intensity value The superimposed values ​​are used as the sampling time. The real-time transmitted light intensity is output, and the real-time transmitted light intensity is denoted as . , Real-time transmitted light intensity It retains the baseline transmission characteristics of the nanocrystalline glass sample and reflects the real-time changes in transmitted light intensity caused by dynamic load.

[0048] See Figure 6 In the figure, the vertical axis represents the real-time reaction force in millinewtons (mN), and the horizontal axis represents the loading time in seconds (s). The solid curve represents the change of the real-time reaction force of the indenter over time during the loading process, while the dashed line is the reference line for the preset threshold force of 20 millinewtons. The curve shows two distinct loading stages, consistent with the loading rate switching logic described in Example 3.

[0049] During the initial loading phase (approximately 0 to 0.8 seconds), the real-time reaction force rapidly rises to the preset threshold force of 20 millinewtons, indicating that the indenter has overcome the influence of microscopic unevenness on the sample surface and established stable contact. At this point, the controller detects that the real-time reaction force has reached 20 millinewtons and triggers a switch from the first loading rate to the second loading rate.

[0050] In the second stage of loading (approximately 0.8 to 10 seconds), the real-time reaction force increases steadily and linearly, from 20 millinewtons to approximately 116 millinewtons. This reflects the indenter continuously pressing the nanocrystalline glass sample at a lower loading rate, achieving precise loading during the plastic deformation stage. The black dots on the curve indicate the moment when the threshold force of 20 millinewtons is reached, clearly distinguishing the two loading rate ranges.

[0051] The figure accurately illustrates the process in Example 3 of extracting the first and second loading rates from the loading rate parameter database based on the nominal thickness of the sample, and combining this with real-time feedback from the force sensor to achieve closed-loop control of the loading rate switching. This ensures that the loading rate is faster during the elastic deformation stage and slower during the plastic deformation stage, thereby obtaining high-precision stress response and transmitted light intensity change data.

[0052] Example 4: In practical implementation, before inputting the transmittance feature value and hardness feature value into the preset quality discrimination model, the process of normalizing the transmittance feature value and hardness feature value is as follows.

[0053] This involves obtaining the sets of transmittance and hardness characteristic values ​​for multiple nanocrystalline glass samples from the same batch. "Same batch" refers to nanocrystalline glass samples produced in the same production furnace using the same raw material formula and the same heat treatment process conditions. The number of nanocrystalline glass samples included in the same batch is denoted as... , The value is a positive integer greater than or equal to 30. For each nanocrystalline glass sample in the same batch, the elastic light transmittance, plastic light transmittance retention rate, and indentation hardness value are extracted according to the method described in the aforementioned embodiments. The elastic light transmittance of all nanocrystalline glass samples in the same batch is used to form an elastic light transmittance set, the plastic light transmittance retention rate of all nanocrystalline glass samples in the same batch is used to form a plastic light transmittance retention rate set, and the indentation hardness value of all nanocrystalline glass samples in the same batch is used to form an indentation hardness value set. The light transmittance characteristic value set is jointly composed of the elastic light transmittance set and the plastic light transmittance retention rate set, and the hardness characteristic value set is composed of the indentation hardness value set.

[0054] Statistical calculations are performed on the values ​​in the set of elastic light transmittance responsivity values ​​to determine the mean and standard deviation of the set. The mean of the set of elastic light transmittance responsivity values ​​is denoted as... The standard deviation of the set of elastic light transmittance responses is denoted as . Mean The calculation method is to combine all elastic light transmittance responsivity sets. Sum of the elastic light transmittance values ​​and divide by . Standard deviation The calculation method involves obtaining the value of each elastic light transmittance responsivity and the mean value in the elastic light transmittance responsivity set. The mean of the sum of the squares of the differences is then taken as the square root of that mean.

[0055] Statistical calculations were performed on the values ​​in the set of plastic light transmittance retention rates to determine the mean and standard deviation of the set. The mean of the set of plastic light transmittance retention rates is denoted as... The standard deviation of the set of plastic light transmittance retention rates is denoted as . Mean The calculation method is to combine all the plastic light transmittance retention rates in the set. Sum the values ​​of plastic light transmittance retention rate and divide by . Standard deviation The calculation method involves obtaining the value of each plastic light transmittance retention rate and the mean value in the set of plastic light transmittance retention rates. The mean of the sum of the squares of the differences is then taken as the square root of that mean.

[0056] Statistical calculations are performed on the values ​​in the set of indentation hardness values ​​to determine the mean and standard deviation of the set. The mean of the set of indentation hardness values ​​is denoted as... The standard deviation of the set of indentation hardness values ​​is denoted as . Mean The calculation method is to include all indentation hardness values ​​in the set. Sum of the indentation hardness values ​​and divide by . Standard deviation The calculation method involves taking the indentation hardness value and the mean value from the set of indentation hardness values. The mean of the sum of the squares of the differences is then taken as the square root of that mean.

[0057] After obtaining the mean and standard deviation, the elastic transmittance of each nanocrystalline glass sample was normalized. The elastic transmittance of the nanocrystalline glass sample to be normalized is denoted as... The normalized elastic light transmittance is denoted as The normalization calculation formula is as follows:

[0058] in, Represents the normalized elastic light transmittance, dimensionless; This represents the original value of the elastic light transmittance responsivity to be normalized, with the unit being the change in transmitted light intensity per unit of reaction force. This represents the mean of the set of elastic light transmittance responsivity values, expressed in units of change in transmitted light intensity per unit of reaction force, derived from the same batch. The elastic light transmittance response of the nanocrystalline glass sample was statistically obtained; This represents the standard deviation of the set of elastic light transmittance responsivity, with units of change in transmitted light intensity per unit of reaction force, from the same batch. The elastic light transmittance response of the nanocrystalline glass sample was statistically obtained.

[0059] The plastic transmittance retention rate of each nanocrystalline glass sample was normalized. The plastic transmittance retention rate of the nanocrystalline glass sample to be normalized is denoted as... The normalized plastic transmittance retention rate is denoted as The formula for normalization is consistent in form with the formula for normalized elastic transmittance, i.e. In the formula This represents the normalized plastic light transmittance retention rate, which is dimensionless. This represents the original value of the plastic light transmittance retention rate to be normalized, with units consistent with the units of the transmitted light intensity. This represents the mean of the set of plastic light transmittance retention rates; It represents the standard deviation of the set of plastic light transmittance retention rates.

[0060] The indentation hardness value of each nanocrystalline glass sample was normalized. The indentation hardness value of the nanocrystalline glass sample to be normalized is denoted as... The normalized indentation hardness value is denoted as The normalization calculation formula is as follows: In the formula This represents the normalized indentation hardness value, which is dimensionless. This represents the original indentation hardness value to be normalized, in gigapascals. This represents the mean of the set of indentation hardness values, in gigapascals. This represents the standard deviation of the set of indentation hardness values, in gigapascals.

[0061] After completing the above normalization process, use the normalized elastic transmittance response rate. Replace the original elastic light transmittance response. Using normalized plastic light transmittance retention rate Replace the original plastic light transmission retention rate Normalized indentation hardness value Replace the original indentation hardness value Normalized elastic light transmittance With normalized plastic light transmittance As a normalized transmittance characteristic value, the normalized indentation hardness value is used. The normalized transmittance feature value and the normalized hardness feature value are used as normalized hardness feature values. The normalized transmittance feature value and the normalized hardness feature value are input into a preset quality discrimination model. The preset quality discrimination model is constructed based on a support vector machine. The three-dimensional input vector of the support vector machine is composed of the normalized elastic transmittance response rate, the normalized plastic transmittance retention rate and the normalized indentation hardness value in sequence.

[0062] See Figure 7 The figure shows the frequency distribution of normalized elastic light transmittance, normalized plastic light transmittance retention, and normalized indentation hardness. The horizontal axis represents the normalized values, ranging from approximately -4 to 4, and the vertical axis represents the frequency, indicating the number of samples within the corresponding interval. The frequency histograms for normalized elastic light transmittance and normalized plastic light transmittance retention are distinguished by diagonal fill, while the normalized indentation hardness values ​​are filled with dots. All three exhibit an approximately normal distribution, with the data mainly concentrated between the normalized values ​​of -2 and 2. The peak frequencies are all located near the normalized values ​​of 0, indicating that the overall fluctuation range of the light transmittance and hardness characteristic values ​​of this batch of nanocrystalline glass samples is limited and concentrated. The distribution of normalized elastic light transmittance is relatively symmetrical, with the peak frequency slightly lower than that of normalized plastic light transmittance retention, the latter showing a more obvious concentration trend near the normalized value of 0. The frequency distribution of normalized indentation hardness values ​​shows a similar trend to that of transmittance characteristic values, but the overall frequency is higher, indicating that the sample size of the hardness data is sufficient and concentrated. This frequency distribution chart reflects the effect of normalization processing in Example 4, which involves statistically analyzing the transmittance and hardness characteristic values ​​of at least 30 nanocrystalline glass samples from the same batch, calculating the mean and standard deviation, and then performing the normalization process. The normalized data meets the input requirements of the support vector machine quality discrimination model, which is beneficial for the model to accurately distinguish whether the samples are qualified or not.

[0063] Example 5: In practice, after outputting the integrated detection results of the nanocrystalline glass sample, the process of associating and storing the integrated detection results with the load-transmittance synchronous response curve is as follows.

[0064] A unique sample identification code is generated for each tested nanocrystalline glass sample. The generation rule for the sample identification code is as follows: combine the testing date, testing batch number, and sample serial number within the batch, separated by underscores. The testing date is represented by eight digits in the format of year, month, and day, for example, 20250318 represents March 18, 2025. The testing batch number consists of four digits, starting from 0001 and incrementing sequentially according to the testing order. The sample serial number within the batch consists of three digits, starting from 001 and incrementing sequentially according to the testing order. The testing date, testing batch number, and sample serial number are concatenated in the format "testing date_testing batch number_sample serial number" to obtain the sample identification code in string form. For example, the sample identification code for the 005th nanocrystalline glass sample in batch 0023, tested on March 18, 2025, is generated as "20250318_0023_005". The sample identification code is automatically generated by the controller of the detection system and stored in the system memory after generation.

[0065] After generating the sample identification code, the sample identification code, integrated test result, and load-transmittance synchronous response curve are stored together in the test database. The test database is built using a relational database management system, which runs on a data server connected to the test system controller, and the two communicate via Ethernet. A data record table named "Nanocrystalline Glass Test Record Table" is established in the test database. The Nanocrystalline Glass Test Record Table contains four fields: Sample Identification Code, Integrated Test Result, Load-Transmittance Synchronous Response Curve Data, and Storage Timestamp. The Sample Identification Code field is set to a variable-length string with a maximum length of 50 characters. The Integrated Test Result field is set to an integer type, with a value of 0 or 1, where 0 indicates a defective product and 1 indicates a qualified product. The Load-Transmittance Synchronous Response Curve Data field is set to a binary large object type to store the serialized load-transmittance synchronous response curve data. The Storage Timestamp field is set to a date and time type to record the precise time the data was written to the database, accurate to the second.

[0066] Before being stored in the detection database, the load-transmission synchronous response curve undergoes serialization. Serialization converts all data points within the load-transmission synchronous response curve into a data stream with a pre-defined structure. The load-transmission synchronous response curve consists of a series of data points, each containing an x-axis value and a y-axis value. The x-axis value represents the reaction force, and the y-axis value represents the transmitted light intensity. During serialization, the reaction force value and transmitted light intensity value for each data point are sequentially written on a line, separated by commas, according to the sampling time axis. Different data points are separated by newline characters, ultimately forming a string. This string is then stored as the load-transmission synchronous response curve data in the load-transmission synchronous response curve data field of the detection database.

[0067] In the testing database, a data record with the sample identifier code as the primary key is established. In the nanocrystalline glass testing record table, the sample identifier code field is set as the primary key constraint. This primary key constraint ensures that each row in the nanocrystalline glass testing record table has a unique sample identifier code, preventing duplicate codes. Once the sample identifier code, integrated testing results, and serialized load-transmittance synchronous response curve data for one nanocrystalline glass sample are prepared, a new record is written to the nanocrystalline glass testing record table using an SQL insert statement. After the new record is written, the storage timestamp field is automatically filled with the current database system time.

[0068] After establishing the aforementioned data records, the integrated test results and load-transmittance synchronous response curve can be retrieved simultaneously using the sample identification code. When querying the test information of a specific nanocrystalline glass sample, the testing system sends a query request to the testing database, which includes the sample identification code to be queried. The testing database performs a query operation in the nanocrystalline glass test record table using the sample identification code as the search condition. After locating the data record matching the sample identification code, it returns the contents of the integrated test result field and the load-transmittance synchronous response curve data field from that data record to the testing system. Upon receiving the returned content, the testing system deserializes the string in the load-transmittance synchronous response curve data field. The deserialization process follows the opposite rules to the serialization process, parsing each line of the string into a data point's reaction force value and transmitted light intensity value, and reconstructs the load-transmittance synchronous response curve. The testing system simultaneously displays the integrated test results and the load-transmittance synchronous response curve graph on the display interface, allowing operators to retrieve and view the complete test information of any tested nanocrystalline glass sample using the sample identification code.

[0069] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for integrated detection of transmittance and hardness based on nanocrystalline glass, characterized in that, Includes the following steps: A dynamic load is applied to the surface of the nanocrystalline glass sample, and stress response data and transmitted light intensity change data of the nanocrystalline glass sample under the dynamic load are collected simultaneously. Based on the temporal correspondence between the stress response data and the transmitted light intensity change data, the specific steps for constructing the load-transmission synchronous response curve of the nanocrystalline glass sample include: Align the real-time reaction force and the real-time transmitted light intensity with the same sampling time axis to obtain the reaction force value and transmitted light intensity value at the same time point. Using the reaction force value as the abscissa and the transmitted light intensity value as the ordinate, a continuous trajectory is plotted from the start to the end of the pressing process to obtain the load-transmission synchronous response curve. The transmittance characteristic values ​​of the nanocrystalline glass sample under different stress states are extracted from the load-transmittance synchronous response curve. At the same time, the hardness characteristic values ​​of the nanocrystalline glass sample are determined based on the loading history of the dynamic load and the stress response data. The transmittance characteristic value and the hardness characteristic value are input into a preset quality discrimination model, and the integrated detection result of the nanocrystalline glass sample is output. The specific steps for extracting the transmittance characteristic values ​​of the nanocrystalline glass sample under different stress states from the load-transmittance synchronous response curve include: Identify the boundary point between the elastic deformation stage and the plastic deformation stage on the load-transmittance synchronous response curve, and take the abscissa corresponding to the boundary point as the yield load value. The slope of the curve within the segment from zero to the yield load value is extracted from the load-transmittance synchronous response curve and used as the elastic transmittance response rate. The average value of the ordinate of the stable section after the horizontal axis exceeds the yield load value is extracted from the load-transmittance synchronous response curve and used as the plastic transmittance retention rate. The elastic light transmittance response rate and the plastic light transmittance retention rate are used together as the light transmittance characteristic value.

2. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 1, characterized in that, The specific steps for applying a dynamic load to the surface of a nanocrystalline glass sample and simultaneously acquiring stress response data and transmitted light intensity change data of the nanocrystalline glass sample under the dynamic load include: The nanocrystalline glass sample is fixed on the stage, and the tip of the indenter is vertically aligned with the test surface area of ​​the nanocrystalline glass sample. The pressure head is controlled to press into the surface of the nanocrystalline glass sample at a preset loading rate. During the pressing process, the real-time reaction force on the pressure head is continuously recorded by a force sensor as the stress response data. While the indenter is being pressed in, incident light emitted from the light source is directed perpendicularly to the indentation position of the indenter. The real-time transmitted light intensity after passing through the nanocrystalline glass sample is continuously recorded by a light intensity detector located on the back of the nanocrystalline glass sample, and is used as the transmitted light intensity change data.

3. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 2, characterized in that, When identifying the boundary between the elastic deformation stage and the plastic deformation stage on the load-transmission synchronous response curve, the position where the first derivative of the curve first changes abruptly is taken as the boundary point.

4. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 3, characterized in that, The specific steps for determining the hardness characteristic value of the nanocrystalline glass sample based on the loading history of the dynamic load and the stress response data include: Read the peak load corresponding to the moment when the indenter reaches the maximum indentation depth from the real-time reaction force; The contact projection area between the indenter and the nanocrystalline glass sample is calculated using the geometric parameters of the indenter and the maximum indentation depth. Dividing the peak load by the contact projection area yields the indentation hardness value of the nanocrystalline glass sample, which is used as the hardness characteristic value.

5. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 4, characterized in that, The specific steps for inputting the transmittance characteristic value and the hardness characteristic value into a preset quality discrimination model and outputting the integrated detection result of the nanocrystalline glass sample include: The elastic light transmittance response rate, the plastic light transmittance retention rate, and the indentation hardness value are combined into a three-dimensional input vector; The three-dimensional input vector is input into a pre-trained quality discrimination model, which is built based on a support vector machine. The training samples include the three-dimensional input vectors of qualified nanocrystalline glass samples and the three-dimensional input vectors of unqualified nanocrystalline glass samples. Obtain the classification label output by the quality discrimination model, and determine whether the nanocrystalline glass sample is a qualified product or an unqualified product based on the classification label.

6. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 2, characterized in that, The specific steps for controlling the pressure head to press into the surface of the nanocrystalline glass sample at a preset loading rate include: Based on the nominal thickness of the nanocrystalline glass sample, the corresponding loading rate parameter is selected from the database; In the initial stage when the pressure head begins to contact the surface of the nanocrystalline glass sample, a first loading rate is used for loading; When the real-time reaction force reaches the preset threshold force, the loading rate is switched to the second loading rate, which is less than the first loading rate. Record the timing sequence of the loading rate change throughout the entire process from the initial contact of the indenter to the achievement of the maximum indentation depth.

7. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 6, characterized in that, The switching between the first loading rate and the second loading rate is achieved through closed-loop feedback control, and the switching is automatically triggered when the real-time reaction force reaches the preset threshold force.

8. The method for integrated detection of transmittance and hardness based on nanocrystalline glass according to claim 2, characterized in that, The specific steps for continuously recording the real-time transmitted light intensity after passing through the nanocrystalline glass sample using a light intensity detector located on the back of the nanocrystalline glass sample include: Before the pressure head begins to press in, the light source and the light intensity detector are activated first, and the initial transmitted light intensity under no-load conditions is recorded as the reference light intensity value. During the pressing process, the light intensity detector continuously collects the transmitted light intensity at a preset sampling frequency. The relative change in transmitted light intensity is obtained by subtracting the reference light intensity value from the transmitted light intensity at each sampling moment. The relative transmitted light intensity change corresponding to each sampling time is superimposed on the reference light intensity value, and then output as the real-time transmitted light intensity at that time.

Images