Online monitoring method for the forming process of micro-optical components with multi-band photosensitive decoupling

Abstract

This invention discloses an online multi-band photosensitive decoupling method for monitoring the forming process of micro-optical components. This method allows for online monitoring and correction of forming process parameters, controlling the forming scale of the micro-surface topology of optical components and diagnosing the operating conditions of equipment. The method includes the following steps: selecting process parameters based on desired height; acquiring multi-band illuminance curves of light during the processing from multiple angles online and extracting feature values ​​through decoupling; combining the correlation between photosensitive feature values ​​and process parameters from past experience data; predicting processing parameters in real time, including hot-pressing temperature, hot-pressing pressure, and holding time; characterizing the surface stress of micro-forming using thermal melting compression theory; and finally, correcting equipment conditions and controlling the micro-forming scale through a feedback control algorithm. This method enables efficient online prediction and diagnosis of multiple parameters in the micro-optical component forming process and solves the time-varying problem in the micro-optical component manufacturing process.

Description

Technical Field

[0001] This invention relates to the fields of intelligent manufacturing technology and processing monitoring, specifically to a method for monitoring the forming process of micro-optical components through online multi-band photosensitive decoupling. Background Technology

[0002] Micro-optical components, characterized by their tiny size and high integration, can improve the optical, physical, and chemical properties of parts, thereby increasing the added value of products. The fine, multi-level microlens array structure on the surface of micro-optical components can achieve even superior added value, forming microstructures with more complex optical functions, characterized by high integration, miniaturization, and multifunctionality. High-value-added optical products often require the fabrication of composite microlens arrays. For example, two-level microlens arrays can be applied to eye-protection lighting, biomimetic compound eye structures, and other fields.

[0003] Hot stamping offers advantages such as low cost and high efficiency, making the industrialization of composite microlens array structures for micro-optical components a viable possibility. However, in the rapid hot stamping production of optical composite microlens arrays, the nonlinear and complex relationship between hot stamping process parameters and the forming height of the composite microlens array makes it difficult to predict workpiece surface stress during the hot stamping process. This leads to insufficient accuracy that is difficult to detect in a timely manner, becoming one of the bottlenecks in production line automation. Furthermore, equipment is affected by environmental factors, sensor drift, and equipment aging, making it difficult to detect potential problems of process parameter drift, resulting in decreased production accuracy. Therefore, it is necessary to incorporate the hot stamping mechanism into the production process of micro-optical components for online accuracy control and equipment status monitoring.

[0004] To address the aforementioned issues, a real-time control device and method for macroscopic photosensitive microarray hot pressing molding (CN201710226928.5) discloses a real-time control method for macroscopic photosensitive microarray hot pressing molding, achieving adaptive control of the microarray molding effect on the macroscopic surface of the product, thereby reducing production costs and improving processing quality and efficiency. However, the optical detection in this patent is only applied to single-layer microstructures and cannot perform online detection for composite microlens arrays. Furthermore, this method only fits the relationship between molding height and illuminance through a linear relationship, failing to reflect the nonlinear relationship between the molding scale of the composite microlens array and the hot pressing process parameters. This method does not utilize multi-band, multi-directional photosensitive technology and does not monitor the equipment status. Summary of the Invention

[0005] The purpose of this invention is to address the issue that the processing accuracy and equipment status of micro-optical components are easily affected by environmental changes, sensor accuracy drift, and equipment aging. This invention provides an online multi-band light-sensing decoupled micro-optical component forming process monitoring method. By decoupling multi-band illuminance curves during processing, a correlation database is established between hot stamping process parameters, illuminance values, and forming dimensions. During processing, an empirical probability algorithm uses the detected illuminance values ​​and the correlation database to predict the current forming dimensions of each level of the microlens array and the equipment processing parameters online. Feedback adjustments are then made to achieve processing process monitoring.

[0006] The present invention is achieved by at least one of the following technical solutions.

[0007] A method for monitoring the forming process of micro-optical components with online multi-band photosensitive decoupling includes the following steps:

[0008] S1. Set system parameters, set the desired composite microlens height h. i * ;

[0009] S2. Based on the desired height of the composite microlens and the experience database formed from past processing, select the hot pressing process parameters suitable for this hot pressing process based on prior probability. The hot pressing process parameters include hot pressing temperature, hot pressing pressure, and holding time.

[0010] S3, Hot stamping forming stage: n light sources and n light receiving devices are placed around the workpiece. Each light source corresponds to a light receiving device to continuously detect the light value when the worktable moves to different positions. The hot stamping process parameters are preset. When the hot stamping platform starts to move upward, all light sources are turned on. These light sources can emit red, green and blue light. Part of the emitted light is received by the light receiving device.

[0011] S4. Characterize the illuminance curve corresponding to the measured value of each color of light received by the light source receiving device. Extract multiple illuminance feature values ​​from each illuminance curve to obtain all illuminance feature values ​​for this hot embossing process. Each illuminance curve is obtained by using the illuminance feature value corresponding to the wavelength of each color of each light source. Based on the empirical database, an algorithm based on prior probability is used to obtain the online detection hot embossing process parameters, the movement speed during mold core forming and mold closing, and the flatness of the workpiece forming. Based on the theoretical model of hot embossing of composite microlens array, the actual workpiece surface stress and hot embossing forming height are obtained through the hot embossing process parameters.

[0012] S5. If the difference between the predicted hot stamping process parameters and the set hot stamping process parameters exceeds the set threshold, the equipment malfunctions and feedback control of the equipment process parameters is required; if it is within the set threshold, proceed to step S6.

[0013] S6. The workstation compares the expected forming height with the predicted forming height. If the height exceeds the allowable error range, the composite microlens height is reset and the process returns to step S2 to adjust the hot stamping process parameters. If the height does not exceed the allowable error range, the process returns to step S3 to continue processing.

[0014] Furthermore, based on prior probability, the hot pressing process parameters suitable for this hot pressing process are selected as follows:

[0015]

[0016] In the formula, k i The parameters for the hot stamping process used in this processing are h. i P(k) represents the array height of each stage of the composite microlens array structure. i |h i P(h) represents the probability that the desired height of the composite microlens array corresponds to the process parameters obtained from empirical data; i |k i ) is the process parameter k in the experience database. i h obtained below i The probability of P(h) i ) for the experience database h i The probability of choosing the highest probability P(k) i |h i () represents the process parameters selected for this application;

[0017] When predicting process parameters, an algorithm based on prior probability can be described as follows:

[0018]

[0019] In the formula, E i q represents all illuminance characteristic values ​​measured by the light source receiving device during this processing. i For the movement speed of the mold core during molding and mold closing, and the flatness of the formed workpiece, P[(k i ,q i )|E i The illuminance characteristic value data obtained during this processing is mapped to the empirical database (11) to obtain the process parameter (k). i ,q i The probability of ) P[E i |(k i ,q i )] refers to the molding height and process parameters (k) in the experience database (11). i ,q i The characteristic value of illuminance measured under the condition is E i Given the probability, choose the one with the highest probability P[(k)]. i ,q i )|Ei ] represents the process parameters for this prediction.

[0020] Furthermore, the workpiece surface stress in the process parameters is predicted using a theoretical model of hot embossing with a composite microlens array:

[0021] σ=σ s δsin(θ0 / 2) / (R(1-cos(θ0 / 2))) (3)

[0022] Where θ0 and R satisfy the following relationship:

[0023]

[0024] Where h m Solve using the following formula:

[0025]

[0026] In the formula, E(T) is the elastic modulus of the material, and h m L is the mechanical compression height, L is the workpiece length, L0 is the width of the mold core platform, and h is the workpiece length. v θ represents the height of the V-shaped microgroove structure on the mold core surface. v θ0 is the angle of the V-shaped microgroove structure on the mold core surface, R is the radius of the microlens arc, δ is the workpiece width, and σ is the angle of the microlens arc. s σ is the wire mesh pressure, T is the workpiece surface stress, a is the hot pressing temperature, a is the workpiece thickness, and F is the mechanical compressive force.

[0027] If we want to predict the height of the large microprism h1 and the small microlens h2 in the composite microlens array:

[0028]

[0029]

[0030] In the formula, k r η is the springback coefficient, r0 is the pore size of the elastic mesh liner, R0 is the equivalent radius of the microgroove, η(T) is the viscosity of the polymer workpiece, t is the holding time, and n is the equivalent coefficient.

[0031] Furthermore, if the predicted hot stamping process parameters are higher than the set hot stamping process parameters, feedback control of the equipment process parameters is required, and the hot stamping process parameter k is set. i '=k i -1,k i The parameters for the hot stamping process used in this processing are specified. If the actual process parameters are lower than the set hot stamping process parameters, then the new process parameters k are set. i '=k i +1.

[0032] Furthermore, if the predicted microlens height is higher than the desired microlens height, the composite microlens height needs to be reset. The newly set microlens height h i '=h i * -1,h i * The desired height of the composite microlens is set; if the predicted microlens height is lower than the desired height, then a new microlens height h is set. i '=h i +1.

[0033] Furthermore, when constructing the experience database, the actual hot-pressing pressure is measured by the hot-pressing sensing platform, the actual hot-pressing temperature is measured by the thermocouple, and the actual holding time is measured by the change in the pressure curve.

[0034] Furthermore, if a composite microlens array is to be formed, an elastic microporous mesh liner needs to be added between the workpiece and the mold core. The liner is made of nylon woven elastic mesh with a mesh count of 200-500 mesh and a pore size of 10-40 μm. It is cut into squares with a side length of 85-90 mm.

[0035] Furthermore, the light receiving device is a spectrometer or a illuminometer, and the light receiving device calculates the illuminance of light in different wavelength bands for each of the mixed emitted light.

[0036] Further empirical databases include the height h of compound microlens arrays detected by profilometry or confocal microscopy. i The actual process parameters k of the hot embossing process detected by thermocouples and pressure sensors i Other monitored process parameters include: the movement speed of the mold core during molding and closing, the flatness of the formed workpiece, and the illuminance characteristic value E of the illuminance curve during the hot stamping process. i The experience database should contain no fewer than 50 sets of data and should be updated regularly to adapt to changes in working conditions. Each set of data in the database should be retained for no more than 100 days.

[0037] Furthermore, the method for characterizing the illuminance measured by the light source receiving device is described as follows:

[0038] Place n light sources on a hot embossing platform, corresponding to n light receiving devices. For the illuminance value of a single wavelength received by a single lux meter during the hot embossing process, take the maximum illuminance value as the hot embossing platform moves upward as E. A Minimum illuminance E during mold closing process B The highest and lowest illuminance values ​​E when the worktable moves downward after molding. C E D As an eigenvalue.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. This invention utilizes the varying refraction and reflection of multi-band and different-directional light waves across various micro-optical components to reflect the height of the composite microstructure array on the workpiece surface. Furthermore, it offers advantages in terms of high efficiency and low cost compared to using instruments such as Taylor profilometers and white light interferometers for product molding quality inspection.

[0041] 2. Establish the correlation between molding dimensions, process parameters, and illuminance characteristic values ​​through an empirical database. Then, predict the height and process parameters using an empirical probabilistic algorithm. The entire process can be carried out during processing, allowing for real-time measurement of the molding height and monitoring of equipment status. Feedback control can be used to control the molding accuracy of the composite microlens.

[0042] 3. This method enables online optical inspection of macroscopic surfaces, reflecting production status in real time. It facilitates timely adjustment of various production parameters based on production status, improving production accuracy and production line automation, and reducing labor costs. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of a method for monitoring the forming process of micro-optical components with online multi-band photosensitive decoupling according to an embodiment of the present invention.

[0044] Figure 2 This is a schematic diagram of light propagating to a light receiving device according to an embodiment of the present invention;

[0045] Figure 3 This is a flowchart of the online micro-optical component fabrication process monitoring method according to an embodiment of the present invention;

[0046] Figure 4 This is a diagram showing the online detection accuracy control of the forming height of the large microprism in the composite microlens array according to an embodiment of the present invention.

[0047] Figure 5 This is a monitoring chart of the temperature, pressure, and time for hot stamping in an embodiment of the present invention;

[0048] The figure shows: 1-Hot press; 2-Hot press mold core; 3-Elastic mesh pad; 41-First light receiving device; 42-Second light receiving device; 5-Hot embossing platform; 61-First light source; 62-Second light source; 71-First thermocouple; 72-Second thermocouple; 8-PMMA polymer substrate; 9-Pressure sensing platform; 10-Data receiving device; 11-Experience database; 12-Workstation. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0050] See Figures 1-5 Taking a two-stage microlens array formed by hot pressing an 85mm×85mm×3mm PMMA polymer substrate as an example, the two-stage microlens array requires the addition of an elastic microporous mesh pad (nylon woven elastic mesh pad 3) between the workpiece and the mold core. The mesh size is 200-500 mesh, the aperture is 10-40μm, and it is cut into squares with a side length of 85-90mm. Two-directional light sensing is used, with red, green, and blue light as the light source, and their center wavelengths being 635nm, 525nm, and 465nm respectively. A single light source and an illuminance meter are placed. The process parameters are monitored during the manufacturing process. The principle of the online multi-band light sensing decoupling micro-optical component manufacturing process monitoring method of the present invention is explained in detail, thereby verifying the technical effect of the present invention.

[0051] like Figure 1 As shown in this embodiment, the online multi-band light-sensing decoupled micro-optical component molding process monitoring method involves placing a pressure sensing platform 9 on a hot embossing platform 5 and placing the workpiece on the pressure sensing platform 9. Two light sources (61, 62) are fixed at the centerline positions on both sides of the workpiece (PMMA polymer substrate 8), with the angle between the two light sources and the center of the workpiece being 90°. Two illuminance meters (41, 42) are placed opposite the two light sources (61, 62). During the molding process, an elastic mesh liner 2 is placed on the surface of the workpiece, and two thermocouples (71, 72) are inserted into the workpiece to measure the temperature. The hot embossing platform 5 is moved up until the workpiece contacts the hot embossing mold core 2 and reaches the hot embossing pressure. After holding the pressure for a period of time, the platform returns to its initial position.

[0052] The light sources (61, 62) can emit light of different wavelengths, including red, green and blue light, such as laser, LED light source, infrared, ultraviolet light source, including RGB light source. Part of the emitted light is received by the light receiving device 4.

[0053] The light receiving device 4 is a spectrometer or a photometer, with units of lux; or an irradiance meter, with units of W / m². 2 The light receiving device 4 calculates the illuminance of light in different wavelength bands for each of the mixed emitted light.

[0054] During this process, two illuminance meters collect illuminance values ​​at different times and transmit them in real time to the data receiving device 10 and store them in the experience database 11. In this embodiment, the experience database 11 is a data storage device. The experience database 11 provides the illuminance values ​​to the workstation 12 after characterizing them. The workstation 12 predicts the hot-pressing process parameters based on the data in the experience database. The experience database consists of empirical data from prior experiments. Its structure includes the hot-pressing pressure p, mold core temperature T, holding time t, and the corresponding illuminance characteristic values ​​E for each direction and wavelength, measured by thermocouples (71, 72) and pressure sensing platform 9.A E B The highest and lowest illuminance values ​​E when the worktable moves downward after molding. C E D The heights of the two-stage microlens array obtained from offline contour detection are: large micro-prism height h1 and small micro-lens height h2.

[0055] like Figure 2 , Figure 3 As shown, the online multi-band photosensitive decoupling micro-optical component forming process monitoring method includes the following steps:

[0056] ① Set system parameters: temperature threshold, pressure threshold, and time threshold are δ1, δ2, and δ3 respectively. Input desired height: Input the desired height of the composite microlens array h1 and h2 in workstation 12. The allowable errors for h1 and h2 are e1 and e2 respectively.

[0057] ② Process Parameter Selection: Based on an empirical database, an empirical probability algorithm is used to select the appropriate hot pressing process parameters for this hot pressing process. The hot pressing process parameters include hot pressing temperature, hot pressing pressure, and holding time.

[0058]

[0059] In the formula, k i The parameters for the hot stamping process used in this processing are h. i P(k) represents the array height of each stage of the composite microlens array structure. i |h i P(h) represents the probability that the desired height of the composite microlens array corresponds to the process parameters obtained from empirical data; i |k i ) is the process parameter k in the experience database. i h obtained below i The probability of choosing the highest probability P(k) i |h i () represents the process parameters selected for this application.

[0060] ③ Set the process parameters and perform hot stamping molding. During the processing, the illuminance emitted by the light source is E. q The illuminance emitted after passing through the workpiece is E o The illuminance incident on the lux meter is E. Illuminance characteristic values ​​for red, green, and blue wavelengths can be obtained. Based on an empirical database, the process parameters predicted using an empirical probability algorithm can be expressed as:

[0061]

[0062] In the formula, E i E represents all illuminance characteristic values ​​E measured by the light source receiving device during this processing.A E B E C E D q i The motion speed of the mold core during molding and mold closing in this processing, and the flatness of the formed workpiece. P[(k i ,q i )|E i The process parameters (k) can be obtained by mapping the illuminance characteristic value data obtained during this processing to the empirical database. i ,q i The probability of ) P[E i |(k i ,q i [)] represents the molding height and process parameters (k) in the experience database. i ,q i The characteristic value of illuminance measured under the condition is E i The probability, that is, calculating each (k) in the empirical database. i ,q i ) condition E i The probability of occurrence is chosen by selecting the maximum probability P[(k)]. i ,q i )|E i ] represents the process parameters for this prediction.

[0063] The method for characterizing illuminance measured by a light source receiving device can be described as follows:

[0064] For the illuminance value of a single wavelength received by a lux meter during the hot embossing process, the maximum illuminance value during the upward movement of the hot embossing platform is taken as E. A Minimum illuminance E during mold closing process B The highest and lowest illuminance values ​​E when the worktable moves downward after molding. C E D As an eigenvalue.

[0065] ④ Analyze the errors between the currently set process parameters and the actual process parameters. If any one of the hot-pressing temperature error ΔT, hot-pressing pressure error Δp, or holding time error Δt exceeds the set threshold, the equipment needs to be checked and the process parameters adjusted accordingly. If the actual process parameters are lower than the set process parameters, then the new process parameters k should be set. i '=k i +1, if the actual process parameters are higher than the set process parameters, then the new process parameter k is set. i '=k i -1. Continue until the process parameter error is within the threshold range.

[0066] As a specific embodiment, the set temperature threshold δ1 is ±2℃, and the pressure threshold δ2 is ±4kg / cm². 2The time threshold δ3 is ±0.5s.

[0067] ⑤ The workpiece surface stress in the process parameters is predicted using a theoretical model of hot embossing with a composite microlens array:

[0068] σ=σ s δsin(θ0 / 2) / (R(1-cos(θ0 / 2))) (3)

[0069] Where θ0 and R satisfy the following relationship:

[0070]

[0071] Where h m Solve using the following formula:

[0072]

[0073] In the formula, E(T) is the elastic model of the material, h m L is the mechanical compression height, L is the workpiece length, L0 is the width of the mold core platform, and h is the workpiece length. v θ represents the height of the V-shaped microgroove structure on the surface. v θ0 is the angle of the V-shaped microgroove structure on the mold core surface, R is the radius of the microlens arc, δ is the workpiece width, and σ is the angle of the microlens arc. s σ is the wire mesh pressure, σ is the workpiece surface stress, T is the hot pressing temperature, a is the workpiece thickness, and F is the mechanical compressive force.

[0074] Predict the heights of the large microprism (h1) and small microlenses (h2) in the composite microlens array:

[0075]

[0076]

[0077] In the formula, k r η is the springback coefficient, r0 is the pore size of the elastic mesh liner, and R0 is the equivalent radius of the microgroove. η(T) is the viscosity of the polymer workpiece, t is the holding time, and n is the equivalent coefficient.

[0078] ⑥ Analyze the error between the current height and the expected height. If the errors Δh1 and Δh2 of the height h1 of the large microprism and the height h2 of the small microlens are both within the range, then there is no need to adjust the process parameters, and the hot stamping process can continue.

[0079] As a specific embodiment, the allowable errors e1 and e2 for h1 and h2 are both set to ±1μm. If either exceeds the allowable error range, the composite microlens height needs to be reset. If the predicted microlens height is higher than the expected microlens height, the new microlens height h is set. i '=hi -1; If the predicted microlens height is lower than the expected microlens height, then the new microlens height h is set. i '=h i +1.

[0080] ⑦ For the reset desired height, readjust the process parameters, use the empirical probability algorithm from step ②, set the process parameters, and then proceed with the processing.

[0081] The following further explains how the method of the present invention achieves precision control and process parameter monitoring in the hot embossing molding of composite microlens arrays.

[0082] Before the production of composite microlens arrays, an empirical database was established, operating at 100℃-130℃ and 100kg / cm². 2 -140 kg / cm 2 Within a range of 1-3 seconds, the process was carried out in one pass at a gradient of 5℃, 5kg / cm³, and 1 second. Illuminance data for the red, green, and blue bands of the two directional light sources were recorded during the hot-pressing process. Thermocouples and pressure sensors measured the temperature, pressure, and time during hot-pressing. The microstructure forming height was monitored using laser confocal microscopy. Illuminance data, process parameter data, and height data for each board were saved to establish an empirical database.

[0083] As one embodiment, the empirical database contains the height h of the composite microlens array detected by profilometry or confocal microscopy. i The actual process parameters k of the hot embossing process detected by thermocouples and pressure sensors i Other monitored process parameters q i This includes: the movement speed during mold core forming and mold closing, the flatness of the formed workpiece, and the characteristic value E of the illuminance curve during the hot stamping process. i The experience database should contain at least 50 data sets and be updated regularly to adapt to changes in operating conditions. Each data set should be retained for no more than 100 days. The database should not be too small to prevent excessively low sample sizes, which could lead to increased errors due to randomness. Timely database updates are necessary because equipment status, environment, and other factors change over time, and updating the database ensures that the data remains relevant to the current processing conditions.

[0084] like Figure 2 (a) is a schematic diagram of light propagating to the light receiving device after being refracted and reflected by a workpiece without microstructures according to an embodiment of the present invention; Figure 2 (b) is a schematic diagram of the light rays propagating to the light receiving device after being refracted and reflected by a workpiece with a small forming height according to an embodiment of the present invention; Figure 2 (c) is a schematic diagram of the light rays propagating to the light receiving device after being refracted and reflected by a workpiece with a large forming height in an embodiment of the present invention.

[0085] The hot pressing process parameters include hot pressing pressure, mold core temperature, and holding time. If the workpiece material is a polymer, the hot pressing pressure is 80 kg / cm². 2 ~200kg / cm 2 The core temperature is 100℃~180℃ and the holding time is 1s~5s. The reason for setting the above adjustment range is that each parameter is more sensitive to the polymer molding scale within the range, and the molding height can easily change significantly within a small range, so as to achieve better detection results.

[0086] like Figure 3 As shown, the desired height of the large microlens is set to h1 = 54 μm and the height of the small microlens to h2 = 8 μm. Process parameters are selected: T = 115℃ and p = 140 kg / cm². 2 t = 3s. After four hot-pressing cycles, the height of the microlens exceeded the error range, so the parameters were reselected. T = 120℃, p = 130kg / cm² were chosen. 2 At t=3s, the overall heights h1 and h2 of the microlens array were within a controllable range. However, during the sixth processing iteration, the predicted temperature exceeded the allowable error range, so temperature feedback adjustment was performed, setting the temperature to 119℃ and processing continued. By the eighth iteration, the height of the large and small structures exceeded the error range, so the parameters were reselected, choosing T=120℃ and p=130kg / cm². 2 , t = 3s.

[0087] like Figure 4 The image shows 10 temperature, pressure, and time measurements. The process parameters can be viewed in real-time during each processing step. During the sixth processing step, the temperature exceeded the allowable error range. After adjustment, the process parameters stabilized within the set allowable range. Figure 5 (a) is a monitoring graph of the hot embossing molding temperature, pressure and time in an embodiment of the present invention; Figure 5 (b) is a monitoring diagram of the hot stamping pressure in an embodiment of the present invention; Figure 5 (c) is a monitoring graph of hot stamping molding time in an embodiment of the present invention.

[0088] The above experiments demonstrate that this method can control the precision of both large and small microlenses within ±2μm, and that temperature, pressure, and time can be controlled within ±2℃ and ±4kg / cm². 2 Within the range of ±0.5s, this method demonstrates that it can intelligently control the production precision of PMMA polymer substrate composite microlens arrays through photosensitive sensing and realize online monitoring of its process parameters.

[0089] In summary, the online multi-band photosensitive decoupled micro-optical component molding process monitoring method intelligently selects process parameters based on the desired microlens height, predicting the molding height online via photosensor during production. When deviations occur, feedback is provided to adjust the desired molding height, and an empirical probabilistic algorithm reselects the process parameters. The hot-press molding process of composite microlens arrays involves complex physical processes of mechanical compression and thermal melt flow. The actual molding scale has a non-linear relationship with the hot-pressing process parameters and illuminance, making it difficult to calculate this relationship using empirical formulas. The empirical probabilistic algorithm can find the most likely hot-pressing process parameters under corresponding illuminance, with a faster response.

[0090] Simultaneously, process parameters are monitored during this process, and adjustments are made promptly if deviations occur. The entire process requires no human intervention, effectively avoiding problems such as poor processing quality and process parameter drift caused by various factors during processing, thereby improving efficiency and saving production costs.

[0091] The above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for monitoring the forming process of micro-optical components with online multi-band photosensitive decoupling, characterized in that, Includes the following steps: S1. Set system parameters, set the desired composite microlens height h. i * ; S2. Based on the desired height of the composite microlens and the experience database formed from past processing, select the hot pressing process parameters suitable for this hot pressing process based on prior probability. The hot pressing process parameters include hot pressing temperature, hot pressing pressure, and holding time. S3, Hot pressing and forming stage: n light sources and n light receiving devices are placed around the workpiece. Each light source corresponds to a light receiving device to continuously detect the light value when the worktable moves to different positions. The hot stamping process parameters are preset, and when the hot stamping platform begins to move upward, all light sources are turned on. These light sources can emit red, green and blue light, and part of the emitted light is received by the light receiving device. S4. Characterize the illuminance curve corresponding to the measured value of each color of light received by the light source receiving device. Extract multiple illuminance feature values ​​from each illuminance curve to obtain all illuminance feature values ​​for this hot embossing process. Each illuminance curve is obtained by using the illuminance feature value corresponding to the wavelength of each color of each light source. Based on the empirical database, an algorithm based on prior probability is used to obtain the online detection hot embossing process parameters, the movement speed during mold core forming and mold closing, and the flatness of the workpiece forming. Based on the theoretical model of hot embossing of composite microlens array, the actual workpiece surface stress and hot embossing forming height are obtained through the hot embossing process parameters. S5. If the difference between the predicted hot stamping process parameters and the set hot stamping process parameters exceeds the set threshold, the equipment malfunctions and feedback control of the equipment process parameters is required; if it is within the set threshold, proceed to step S6. S6. The workstation compares the expected forming height with the predicted forming height. If the height exceeds the allowable error range, the composite microlens height is reset and the process returns to step S2 to adjust the hot stamping process parameters. If the height does not exceed the allowable error range, the process returns to step S3 to continue processing.

2. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that: Based on prior probability, the hot stamping process parameters suitable for this hot pressing process are selected as follows: In the formula, k i The parameters for the hot stamping process used in this processing are h. i P(k) represents the array height of each stage of the composite microlens array structure. i |h i P(h) represents the probability that the desired height of the composite microlens array corresponds to the process parameters obtained from empirical data; i |k i ) is the process parameter k in the experience database. i h obtained below i The probability of P(h) i ) for the empirical database h i The probability of choosing the highest probability P(k) i |h i () represents the process parameters selected for this application; When predicting process parameters, an algorithm based on prior probability can be described as follows: In the formula, E i q represents all illuminance characteristic values ​​measured by the light source receiving device during this processing. i For the movement speed of the mold core during molding and mold closing, and the flatness of the formed workpiece, P[(k i ,q i )|E i The illuminance characteristic values ​​obtained during this processing are mapped to the empirical database (11) to obtain the process parameters (k). i ,q i The probability of ) P[E i |(k i ,q i )] refers to the molding height and process parameters (k) in the empirical database (11). i ,q i The characteristic value of illuminance measured under the condition is E i Given the probability, choose the maximum probability P[(k)]. i ,q i )|E i ] represents the process parameters for this prediction.

3. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that, The workpiece surface stress in the process parameters is predicted using a theoretical model of hot embossing with a composite microlens array: s = s s δsin(θ0 / 2) / (R(1-cos(θ0 / 2))) (3) Where θ0 and R satisfy the following relationship: Where h m Solve using the following formula: In the formula, E(T) is the elastic modulus of the material, and h m L is the mechanical compression height, L is the workpiece length, L0 is the width of the mold core platform, and h is the workpiece length. v θ represents the height of the V-shaped microgroove structure on the mold core surface. v θ0 is the angle of the V-shaped microgroove structure on the mold core surface, R is the radius of the microlens arc, δ is the workpiece width, and σ is the angle of the microlens arc. s σ is the wire mesh pressure, T is the workpiece surface stress, a is the hot pressing temperature, a is the workpiece thickness, and F is the mechanical compressive force. If we want to predict the height of the large microprism h1 and the small microlens h2 in the composite microlens array: In the formula, k r η is the springback coefficient, r0 is the pore size of the elastic mesh liner, R0 is the equivalent radius of the microgroove, η(T) is the viscosity of the polymer workpiece, t is the holding time, and n is the equivalent coefficient.

4. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that: If the predicted hot stamping process parameters are higher than the set hot stamping process parameters, feedback control of the equipment process parameters is required, and the hot stamping process parameter k needs to be set. i '=k i -1,k i The parameters for the hot stamping process used in this processing are specified. If the actual process parameters are lower than the set hot stamping process parameters, then the new process parameters k are set. i '=k i +1.

5. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that: If the predicted microlens height is higher than the expected microlens height, the composite microlens height needs to be reset. The newly set microlens height h i '=h i * -1,h i * The desired height of the composite microlens is set; if the predicted microlens height is lower than the desired height, then a new microlens height h is set. i '=h i +1.

6. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that: When building the experience database, the actual hot-pressing pressure is measured by the hot-pressing sensing platform, the actual hot-pressing temperature is measured by the thermocouple, and the actual holding time is measured by the change in the pressure curve.

7. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that, If a composite microlens array is to be formed, an elastic microporous mesh liner needs to be added between the workpiece and the mold core. The liner is made of nylon woven elastic mesh with a mesh count of 200-500 mesh and a pore size of 10-40 μm. It is cut into squares with a side length of 85-90 mm.

8. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that: The light receiving device is a spectrometer or a illuminometer. The light receiving device calculates the illuminance of different wavelength bands for each of the mixed emitted light.

9. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to claim 1, characterized in that: The empirical database includes the height h of compound microlens arrays detected by profilometry or confocal microscopy. i The actual process parameters k of the hot embossing process detected by thermocouples and pressure sensors i Other monitored process parameters include: the movement speed of the mold core during molding and closing, the flatness of the formed workpiece, and the illuminance characteristic value E of the illuminance curve during the hot stamping process. i The experience database should contain no fewer than 50 sets of data and should be updated regularly to adapt to changes in working conditions. Each set of data in the database should be retained for no more than 100 days.

10. The online multi-band photosensitive decoupling micro-optical component forming process monitoring method according to any one of claims 1 to 9, characterized in that: The method for characterizing illuminance measured by a light source receiving device is described as follows: Place n light sources on a hot embossing platform, corresponding to n light receiving devices. For the illuminance value of a single wavelength received by a single lux meter during the hot embossing process, take the maximum illuminance value as the hot embossing platform moves upward as E. A Minimum illuminance E during mold closing process B The highest and lowest illuminance values ​​E when the worktable moves downward after molding. C E D As an eigenvalue.

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