Glass substrate laser drilling thermal stress real-time regulation and control method and system

Abstract

The invention provides a glass substrate laser drilling thermal stress real-time regulation and control method and system, and relates to the technical field of laser processing, and the method comprises the following steps: respectively and correspondingly generating a thermal stress wave function and a deformation rate based on a collected three-dimensional temperature gradient field and a surface micro-deformation signal of a drilling area, and calculating a real-time thermal stress value according to the thermal stress wave function; based on the surface micro-deformation signal and the deformation rate, when a preset condition is met, triggering deformation early warning, and generating a deformation abrupt change area; generating compensation phase distribution based on the thermal stress wave function, and performing phase modulation on the deformation abrupt change area according to the compensation phase distribution to generate a transient modulation stress field; the margin coefficient is calculated according to the three-dimensional temperature gradient field, the current drilling depth and the material parameters of the glass substrate, hierarchical control is carried out in combination with the margin coefficient and the real-time thermal stress value, thermal stress distribution is dynamically regulated and controlled, the cracking problem caused by thermal stress concentration is effectively prevented, and the machining quality and the production efficiency are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a method and system for real-time control of thermal stress in laser drilling of glass substrates. Background Technology

[0002] Laser drilling technology is widely used in the processing of glass substrates due to its high precision and non-contact processing characteristics.

[0003] However, the high temperature generated during laser drilling can cause uneven distribution of thermal stress inside the glass substrate, leading to micro-deformation or even cracking in the drilling area and its surroundings, which seriously affects the processing quality and yield.

[0004] Traditional laser drilling technology often lacks real-time monitoring and effective control of thermal stress, making it difficult to effectively control the damage caused by thermal stress to the glass substrate while ensuring processing efficiency.

[0005] In the existing technology, although there are some methods to reduce thermal stress by adjusting laser parameters or using auxiliary cooling, these methods are often slow to respond and cannot control the sudden changes in thermal stress that occur during the drilling process in real time and with precision.

[0006] Furthermore, the monitoring and early warning mechanisms for micro-deformation on the surface of glass substrates are not perfect, making it difficult to take effective measures to prevent further development of deformation in the early stages of deformation.

[0007] Therefore, it is necessary to provide a method and system for real-time control of thermal stress in laser drilling of glass substrates to solve the above-mentioned technical problems. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a method and system for real-time control of thermal stress during laser drilling of glass substrates. By real-time monitoring and dynamic control of the thermal stress distribution during the laser drilling process of glass substrates, cracking caused by thermal stress concentration is effectively prevented, thereby improving processing quality and production efficiency.

[0009] This invention provides a method for real-time control of thermal stress in laser drilling of glass substrates, comprising a main laser device for generating a main beam, a laser compensation device for generating a compensation beam, and a spatial light modulator coupled in the optical path of the laser compensation device. The control method includes the following steps:

[0010] Based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, thermal stress wave function and deformation rate are generated respectively, and real-time thermal stress value is calculated according to the thermal stress wave function.

[0011] Based on the surface micro-deformation signal and the deformation rate, a deformation warning is triggered when a preset condition is met, and a deformation abrupt change region is generated.

[0012] Based on the thermal stress wave function, a compensation phase distribution is generated by a spatial light modulator, and the compensation beam is driven to perform phase modulation on the deformation abrupt region according to the compensation phase distribution to generate a transient modulated stress field.

[0013] The margin coefficient is calculated based on the three-dimensional temperature gradient field, the current drilling depth acquired in real time, and the material parameters of the pre-loaded glass substrate. The margin coefficient and the real-time thermal stress value are then combined to implement graded control.

[0014] Preferably, the control method further includes:

[0015] The fringe order is measured for the transient modulated stress field in the deformation abrupt region, and the margin coefficient is corrected when the fringe order meets a preset correction condition.

[0016] Preferably, the step of generating a thermal stress wave function and a deformation rate based on the acquired three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, respectively, and calculating the real-time thermal stress value based on the thermal stress wave function, includes:

[0017] Real-time acquisition of three-dimensional temperature gradient field in the borehole area in Let be the spatial coordinates, t be the time variable, and a thermal stress wave function be generated based on the three-dimensional temperature gradient field, wherein the thermal stress wave function... The expression is:

[0018]

[0019] Where E is Young's modulus, α is the coefficient of thermal expansion, v is Poisson's ratio, ω is the characteristic thermal oscillation frequency, and i is the imaginary unit;

[0020] Surface micro-deformation signals are acquired synchronously, and the deformation rate is calculated based on the surface micro-deformation signals, wherein the formula for calculating the deformation rate is:

[0021]

[0022] in Let δ(t) be the deformation rate, Δt be the time differential step size, and δ(t) and δ(t+Δt) be the deformation at time t and time (t+Δt), respectively.

[0023] The real-time thermal stress value is calculated based on the thermal stress wave function, wherein the formula for calculating the real-time thermal stress value is:

[0024]

[0025] Where σ th Represents the real-time thermal stress value, where Re[·] represents the real part.

[0026] Preferably, the step of triggering a deformation warning and generating a deformation abrupt change region based on the surface micro-deformation signal and the deformation rate when a preset condition is met includes:

[0027] Based on the deformation rate and surface micro-deformation signal, a triple criterion is calculated, which includes:

[0028] Temporal abrupt change criterion: Where v0 is the average deformation rate of the current drilling cycle.

[0029] Statistical deviation criterion: Where MA(δ,t-10) is the moving average of the deformation over the previous 10ms.

[0030] Frequency domain energy criterion: Where η0 is the average proportion of frequency band energy in historical processing, and FFT[δ(f)] is the Fourier transform of the deformed signal. The energy range is from 10 to 50 kHz. Total energy across the entire frequency band;

[0031] When the time-domain abrupt change criterion C1, the statistical deviation criterion C2, and the frequency-domain energy criterion C3 are all satisfied simultaneously, a deformation abrupt change warning is triggered, and the coordinate set of the deformation abrupt change region is output, wherein the coordinate set Ω of the deformation abrupt change region is... risk Represented as:

[0032]

[0033] Where δ0 is the dynamic deformation threshold, and δ0=1.5×MA(δ,t-10), For position The deformation at time t.

[0034] Preferably, the step of generating a compensated phase distribution based on the thermal stress wavefunction using a spatial light modulator and driving the compensated beam to perform phase modulation on the deformation abrupt region according to the compensated phase distribution to generate a transient modulated stress field includes:

[0035] A compensated phase distribution is generated based on the thermal stress wavefunction.

[0036]

[0037] Where arg(·) is the argument function of the complex number;

[0038] When a deformation warning is triggered, the spatial light modulator will be driven to compensate for the phase distribution. Focusing on the set of coordinates Ω of the region of abrupt deformation risk The compensation beam is distributed according to the compensation phase. The coordinate set Ω of the deformation abrupt region risk To conduct intervention and regulation;

[0039] The coordinate set Ω of the compensation beam and the main beam in the abrupt deformation region risk Destructive interference generates a transient modulated stress field. And satisfy

[0040] Preferably, the formula for calculating the margin coefficient k is:

[0041]

[0042] Where d current d represents the current drilling depth. target T represents the target borehole depth in the material parameters. melt The softening point is a parameter in the material specifications. This represents the maximum modulus of the three-dimensional temperature gradient field throughout the entire borehole region.

[0043] Preferably, the implementation of the hierarchical control includes:

[0044] If σ th <k·σ critical The pulse energy of the main laser is increased by a preset multiple.

[0045] If σ th ≥k·σ critical Turn on the helium cooling system and reduce the current scanning speed according to the preset ratio.

[0046] Preferably, the correction formula for the margin coefficient is:

[0047] k new =k-0.05ΔN

[0048] Where ΔN is the stripe order, k new This is the corrected margin factor.

[0049] The present invention also provides a real-time thermal stress control system for laser drilling of glass substrates, used to execute the aforementioned real-time thermal stress control method for laser drilling of glass substrates, and configured with a main laser device for generating a main beam, a laser compensation device for generating a compensation beam, and a spatial light modulator coupled in the optical path of the laser compensation device. The system further includes:

[0050] The parameter calculation module is used to generate thermal stress wave function and deformation rate based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, respectively, and calculate the real-time thermal stress value according to the thermal stress wave function.

[0051] The deformation early warning module is used to trigger a deformation early warning and generate a deformation abrupt change region when preset conditions are met, based on the surface micro-deformation signal and the deformation rate.

[0052] The phase modulation module is used to generate a compensation phase distribution based on the thermal stress wave function through a spatial light modulator, and drive the compensation beam to perform phase modulation on the deformation abrupt region according to the compensation phase distribution to generate a transient modulated stress field.

[0053] The dynamic hierarchical control module is used to calculate the margin coefficient based on the three-dimensional temperature gradient field, the current drilling depth acquired in real time, and the material parameters of the pre-loaded glass substrate, and to implement hierarchical control in combination with the margin coefficient and the real-time thermal stress value.

[0054] Preferably, the control system further includes:

[0055] The coefficient correction module is used to measure the fringe level of the transient modulated stress field in the deformation abrupt region, and to correct the margin coefficient when the fringe level meets the preset correction conditions.

[0056] Compared with related technologies, the method and system for real-time control of thermal stress in laser drilling of glass substrates provided by the present invention have the following advantages:

[0057] This invention enables real-time monitoring and dynamic control of thermal stress during laser drilling of glass substrates by configuring a main laser device, a laser compensation device, and a spatial light modulator.

[0058] Specifically, this scheme can calculate the thermal stress value in real time and trigger deformation warning based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area. Then, it generates a compensation phase distribution through a spatial light modulator, drives the compensation beam to perform phase modulation on the deformation abrupt region, and generates a transient modulated stress field to offset part of the thermal stress.

[0059] Meanwhile, by combining the margin coefficient and real-time thermal stress value to implement graded control, problems such as glass substrate cracking caused by thermal stress concentration during drilling are effectively prevented, thereby improving processing quality and yield. Attached Figure Description

[0060] Figure 1A flowchart of a method for real-time control of thermal stress in laser drilling of glass substrates provided by the present invention;

[0061] Figure 2 The present invention provides a module structure diagram of a real-time thermal stress control system for laser drilling of glass substrates. Detailed Implementation

[0062] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, not all structures. Moreover, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0063] It should also be noted that, for ease of description, the accompanying drawings show only the parts relevant to the invention and not all of them. Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but it may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0064] Example 1

[0065] This invention provides a method for real-time control of thermal stress in laser drilling of glass substrates, comprising a main laser device for generating a main beam, a laser compensation device for generating a compensation beam, and a spatial light modulator coupled in the optical path of the laser compensation device. (Reference) Figure 1 As shown, the control method includes the following steps:

[0066] S1: Based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, a thermal stress wave function and deformation rate are generated respectively, and the real-time thermal stress value is calculated according to the thermal stress wave function.

[0067] Specifically, step S1 includes the following steps:

[0068] S11: Real-time acquisition of the three-dimensional temperature gradient field in the borehole area in Let be the spatial coordinates, t be the time variable, and a thermal stress wave function be generated based on the three-dimensional temperature gradient field, wherein the thermal stress wave function... The expression is:

[0069]

[0070] Where E is Young's modulus, α is the coefficient of thermal expansion, v is Poisson's ratio, ω is the characteristic thermal oscillation frequency, and i is the imaginary unit.

[0071] In this embodiment, a high-speed infrared thermal imager (frame rate ≥ 1kHz, spatial resolution ≤ 5μm) is used to scan the borehole area in real time to acquire three-dimensional temperature distribution data, and the temperature gradient field is calculated through spatial difference. Spatial grid coordinates The grid size is 10μm × 10μm. The Young's modulus E (calibrated by the three-point bending test ISO14704, typical value 70GPa), coefficient of thermal expansion α, and Poisson's ratio v of the glass substrate are read from the pre-stored material database.

[0072] Based on thermal diffusivity s=K / ρc p The thermal oscillation frequency ω = 2πs / L is calculated based on the characteristic size L of the heat-affected zone (taken as the current laser spot diameter). 2 Where K is thermal conductivity, ρ is density, and c is density. p It is the specific heat capacity. Ultimately, a thermal stress wave function is generated, where the thermoelastic constitutive term... Converting the temperature gradient into stress, the dynamic oscillation term e -iωt Describe the stress fluctuations caused by thermal shock.

[0073] S12: Synchronously acquire surface micro-deformation signals and calculate the deformation rate based on the surface micro-deformation signals, wherein the formula for calculating the deformation rate is:

[0074]

[0075] in Let denot be the deformation rate, Δt be the time differential step size, and δ(t) and δ(t+Δt) be the deformation at time t and time (t+Δt).

[0076] In this embodiment, a laser interferometer (wavelength 632.8 nm) is used in conjunction with digital image correlation (DIC) to acquire the surface micro-deformation field at a sampling rate of 10 kHz. Spatial resolution ≤ 2μm. For the same point Five-point central difference calculation for continuous deformation:

[0077] (Fixed time step Δt = 0.1ms).

[0078] To suppress measurement noise, a Gaussian filter with a standard deviation of 0.5 μm was added, and outliers were removed (when...). (Time is considered as interference). This deformation rate formula is derived from the limit definition. The central difference method quantifies the instantaneous deformation rate of materials, achieving a balance between computational accuracy and noise resistance, and can sensitively capture abrupt deformation changes caused by microcrack propagation.

[0079] S13: Calculate the real-time thermal stress value based on the thermal stress wave function, wherein the formula for calculating the real-time thermal stress value is:

[0080]

[0081] Where σ th Represents the real-time thermal stress value, where Re[·] represents the real part.

[0082] In this embodiment, the real part of the thermal stress wave function is extracted: It covers millions of grid points in the borehole area. The Kd-tree spatial indexing algorithm is used to quickly search for the maximum spatial value σ. th Eliminate interference from the 50μm boundary region and locate the coordinates of the stress concentration point. Absolute value calculation eliminates compressive stress interference (glass failure is dominated by tensile stress), and the maximum value locks the most dangerous area to drive subsequent control. Real-time output σ th Up to step S4, simultaneously record Used for monitoring abnormal temperature fields, ensuring that the stress state refresh cycle is ≤1ms.

[0083] S2: Based on the surface micro-deformation signal and the deformation rate, a deformation warning is triggered when the preset conditions are met, and a deformation abrupt change region is generated.

[0084] Specifically, step S2 includes the following steps:

[0085] S21: Based on the deformation rate and surface micro-deformation signal, calculate the triple criteria, which include:

[0086] Temporal abrupt change criterion: Where v0 is the average deformation rate of the current drilling cycle.

[0087] Statistical deviation criterion: Where MA(δ,t-10) is the moving average of the deformation over the previous 10ms.

[0088] Frequency domain energy criterion: Where η0 is the average proportion of frequency band energy in historical processing, and FFT[δ(f)] is the Fourier transform of the deformed signal. The energy range is from 10 to 50 kHz. This represents the total energy across the entire frequency band.

[0089] In this embodiment, the deformation rate and surface micro-deformation field output in step S12 are received and real-time data preprocessing is performed:

[0090] Baseline calculation:

[0091] Calculate the average deformation rate during the current drilling cycle (since drilling began). (N is the number of sampling points within the period) to establish a deformation acceleration benchmark;

[0092] The moving average is calculated by storing the deformation data of the first 10ms in a circular buffer. It represents the level of short-term historical deformation.

[0093] Frequency domain analysis:

[0094] Perform a 1024-point FFT transform on the deformation signal Frequency domain energy is calculated using an FPGA pipeline.

[0095] The average energy percentage η0 in the 10-50kHz frequency band during historical processing is calculated, with adaptive noise background.

[0096] When using the time-domain abrupt change criterion, capturing deformation acceleration (microcrack propagation characteristics) exceeding 3 times the baseline indicates that the deformation acceleration has exceeded the material's toughness limit, and the hardware comparator completes the judgment within 1μs.

[0097] When using statistical deviation criteria, the detection of deformation jumps that significantly deviate from the historical mean (gradual interference filtering) relies on rapid iteration of a circular buffer.

[0098] When using the frequency domain energy criterion, the radio frequency band (10-50kHz) for glass crack acoustic emission as defined by the ISO13380 standard is captured, with an FPGA computation delay of ≤10μs.

[0099] The warning is triggered and the process proceeds to step S22 only when C1, C2, and C3 are met simultaneously.

[0100] S22: When the time-domain abrupt change criterion C1, the statistical deviation criterion C2, and the frequency-domain energy criterion C3 are simultaneously satisfied, a deformation abrupt change warning is triggered, and the coordinate set of the deformation abrupt change region is output, wherein the coordinate set Ω of the deformation abrupt change region is... risk Represented as:

[0101]

[0102] Where δ0 is the dynamic deformation threshold, and δ0=1.5×MA(δ,t-10), For position The deformation at time t.

[0103] In this embodiment, when all three criteria are met simultaneously, the dynamic deformation threshold is calculated and the deformation abrupt region is generated according to the above formula.

[0104] S3: Based on the thermal stress wave function, a compensation phase distribution is generated by a spatial light modulator, and the compensation beam is driven to perform phase modulation on the deformation abrupt region according to the compensation phase distribution to generate a transient modulated stress field.

[0105] Specifically, step S3 includes the following steps:

[0106] S31: Generate a compensated phase distribution based on the thermal stress wavefunction.

[0107]

[0108] Where arg(·) is the argument function of the complex number.

[0109] In this embodiment, the thermal stress wave function is received, and its real stress field is first extracted. This real part characterizes the actual thermal stress distribution inside the material. The angle of the negative real part in the complex plane is calculated using the argument function arg(·). This operation precisely locates the phase reversal direction of the thermal stress wave. A compensated phase distribution is then generated. in A reverse phase control reference is established, while +π introduces a strict half-wavelength phase shift (corresponding to an optical path difference λ / 2) to ensure that the compensation beam and the main beam satisfy the destructive interference condition I in the processing area. total =|E comp -E main | 2 (I total To compensate for the total light intensity after the beam and the main beam are superimposed, E comp To compensate for the electric field amplitude of the beam, E main The electric field amplitude of the main beam lays the foundation for subsequent physical cancellation of thermal stress.

[0110] S32: When a deformation warning is triggered, the spatial light modulator will be driven to compensate for the phase distribution. Focusing on the set of coordinates Ω of the region of abrupt deformation risk The compensation beam is distributed according to the compensation phase. The coordinate set Ω of the deformation abrupt region risk Intervention and regulation are carried out.

[0111] In this embodiment, when a deformation abrupt change warning is triggered, the set of coordinates of the deformation abrupt change region (including the center coordinates (x, y, x)) is obtained. c ,y c and control radius r sisk Driving the spatial light modulator (SLM) to perform region-selective phase loading: in Ω risk Region overlay focusing phase term (Focal length f = 100mm), generate focused phase distribution The compensation beam (wavelength λ2 = 355 nm) is focused at the center of the risk area, increasing the energy density by 3 times; the original energy density is maintained in the non-risk area. Distribution. After the compensation beam is emitted according to this phase distribution, it produces destructive interference with the main laser (λ1 = 1064 nm) in the spatially overlapping region. The interference effect is verified by real-time monitoring of the contrast of the interference fringes (required to be >80%) using a CCD camera, ensuring that the light field energy is minimized.

[0112] S33: The coordinate set Ω of the compensation beam and the main beam in the abrupt deformation region. risk Destructive interference generates a transient modulated stress field. And satisfy

[0113] In this embodiment, based on the coherently modulated synthesized light field E total =E comp +E main Calculate the transient modulation stress field Where η = 0.3 is the photo-to-thermal conversion efficiency, and I0 is the intensity of the main beam acting alone. This formula quantifies the effect of destructive interference on the cancellation of thermal stress: when the interference is completely destructive (I... total →0), thermal stress is suppressed to the greatest extent. Finally, Ω was measured using a fiber Bragg grating sensor. risk The stress distribution in the region must meet the verification conditions. Ensure that the peak thermal stress is reduced by at least 50%. If this is not achieved, adjust the compensation beam energy in real time until the conditions are met.

[0114] S4: Calculate the margin coefficient based on the three-dimensional temperature gradient field, the current drilling depth acquired in real time, and the material parameters of the pre-loaded glass substrate, and implement graded control by combining the margin coefficient and the real-time thermal stress value.

[0115] In step S4, the formula for calculating the margin coefficient k is:

[0116]

[0117] Where d current d represents the current drilling depth. target T represents the target borehole depth in the material parameters. melt The softening point is a parameter in the material specifications. This represents the maximum modulus of the three-dimensional temperature gradient field throughout the entire borehole region.

[0118] In this embodiment, a three-dimensional temperature gradient field is received in real time, and the maximum modulus of the entire field is calculated in parallel using a GPU. This value characterizes the thermal shock intensity at the most dangerous point in the borehole area. The current borehole depth d is acquired simultaneously. current (Laser ranging accuracy ±2μm), and loaded pre-stored material parameters: target borehole depth d target (From processing technology database), softening point T melt (Material property library calibration values). Risk compensation item calculated based on depth ratio. The tanh function acts as follows: In shallow processing (d) current / d target When <0.5), the output is approximately 0.8 (conservative control); for deep processing (d) current / d target When the value is greater than 0.8, the output is approximately 0.9 (with relaxed margin). Coefficients 5 and -2.5 precisely pinpoint the inflection point of the function to 50% of the borehole depth. The final margin coefficients are generated, including the thermal margin term. Quantify the percentage of the maximum temperature gradient relative to the material limit (when And T melt =At 600℃, the margin approaches zero), depth compensation term R depth The risk characteristics of the dynamic adaptation processing stage are used, and the output value k serves as the core parameter of the dynamic safety threshold benchmark.

[0119] In step S4, the implementation of the hierarchical control includes:

[0120] If σ th <k·σ critical The pulse energy of the main laser is increased by a preset multiple.

[0121] If σ th ≥k·σ critical Turn on the helium cooling system and reduce the current scanning speed according to the preset ratio.

[0122] In this embodiment, the real-time thermal stress value σ is combined with th and the critical tensile strength σ of the pre-stored material critical (Three-point bending test calibration value), calculate the dynamic safety threshold k·σ critical Execute dual-mode decision logic:

[0123] High-efficiency processing mode (σ) th <k·σ critical ):

[0124] Increase the main laser pulse energy to (Energy increase of 20%), by increasing the single-pulse energy ΔE = 0.2E p Accelerate material removal and maximize drilling efficiency within safety margins;

[0125] Stress protection mode (σ) th ≥k·σcritical ):

[0126] Turn on the helium cooling system (flow rate ≥ 20 L / min) to increase the convective heat transfer coefficient by 3 times;

[0127] Reduce scan speed to v new =0.8v safe (Speed ​​reduction of 20%), prolonging the heat treatment time by 25%, and synergistically inhibiting heat accumulation.

[0128] S5: Measure the fringe order of the transient modulated stress field in the deformation abrupt region, and correct the margin coefficient when the fringe order meets the preset correction conditions.

[0129] In step S5, the correction formula for the margin coefficient is:

[0130] k new =k-0.05ΔN

[0131] Where ΔN is the stripe order, k new This is the corrected margin factor.

[0132] In this embodiment, for regions with abrupt deformation, a polarized photoelastic system (white light source + high-speed polarization camera, sampling rate ≥1kHz) is used to acquire stress fringe patterns in real time. The fringe order is calculated based on the stress-optics law.

[0133]

[0134] The stress optical coefficient C (typical value for borosilicate glass is 2.5 × 10⁻⁶) is among them. -12 m 2 / N) characterizes the birefringence response of the material; the principal stress difference Δσ is inversely derived from the fringe density; the physical scale of the fringe density is jointly determined by the substrate thickness d (0.1–1.0 mm) and the center wavelength λ (550 nm). In Ω risk Divide the region into 10×10 grids (grid size 100μm) and calculate the fringe density N of each grid. local =Number of stripes / 1mm, take the maximum value of the area ΔN = maxN local As an output, ΔN directly quantifies the local residual stress intensity (ΔN∝Δσ). When ΔN>3 stripes / mm (corresponding to stress>15MPa), it indicates insufficient stress compensation.

[0135] When ΔN > 3 fringes / mm is detected, the margin coefficient correction process is triggered:

[0136] Execute the corrected formula k new =k-0.05ΔN, where the physical meaning of the coefficient 0.05 is that for every 1 level of stripes exceeding the standard, the margin coefficient decreases by 0.05 (the safety threshold is tightened by 5%);

[0137] If k new <0.1, force setting k new =0.1, to avoid over-correction that could cause processing to stall.

[0138] Feedback update system: Correction value k new The feedback is sent to step S4, where the updated value is directly called to calculate the dynamic safety threshold in the next drilling cycle.

[0139] Example 2

[0140] This invention also provides a real-time thermal stress control system for laser drilling of glass substrates, used to execute the aforementioned real-time thermal stress control method for laser drilling of glass substrates. The system includes a main laser device for generating a main beam, a laser compensation device for generating a compensation beam, and a spatial light modulator coupled to the optical path of the laser compensation device. (See reference...) Figure 2 As shown, the system also includes:

[0141] The parameter calculation module 100 is used to generate thermal stress wave function and deformation rate based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, respectively, and calculate the real-time thermal stress value according to the thermal stress wave function.

[0142] The deformation early warning module 200 is used to trigger a deformation early warning and generate a deformation abrupt change region when preset conditions are met, based on the surface micro-deformation signal and the deformation rate.

[0143] The phase modulation module 300 is used to generate a compensation phase distribution based on the thermal stress wave function through a spatial light modulator, and drive the compensation beam to perform phase modulation on the deformation abrupt region according to the compensation phase distribution to generate a transient modulated stress field.

[0144] The dynamic hierarchical control module 400 is used to calculate the margin coefficient based on the three-dimensional temperature gradient field, the current drilling depth acquired in real time, and the material parameters of the pre-loaded glass substrate, and to implement hierarchical control in combination with the margin coefficient and the real-time thermal stress value.

[0145] The coefficient correction module 500 is used to measure the fringe level of the transient modulated stress field in the deformation abrupt region, and to correct the margin coefficient when the fringe level meets the preset correction conditions.

[0146] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0147] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium capable of carrying or storing data.

[0148] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

Claims

1. A method for real-time control of thermal stress in laser drilling of glass substrates, comprising a main laser device for generating a main beam, a laser compensation device for generating a compensation beam, and a spatial light modulator coupled in the optical path of the laser compensation device, characterized in that, The control method includes the following steps: Based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, thermal stress wave function and deformation rate are generated respectively, and real-time thermal stress value is calculated according to the thermal stress wave function. Based on the surface micro-deformation signal and the deformation rate, a deformation warning is triggered when a preset condition is met, and a deformation abrupt change region is generated. Based on the thermal stress wave function, a compensation phase distribution is generated by a spatial light modulator, and the compensation beam is driven to perform phase modulation on the deformation abrupt region according to the compensation phase distribution to generate a transient modulated stress field. The margin coefficient is calculated based on the three-dimensional temperature gradient field, the current drilling depth acquired in real time, and the material parameters of the pre-loaded glass substrate. The margin coefficient and the real-time thermal stress value are then combined to implement graded control.

2. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 1, characterized in that, The control method also includes: The fringe order is measured for the transient modulated stress field in the deformation abrupt region, and the margin coefficient is corrected when the fringe order meets a preset correction condition.

3. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 2, characterized in that, The three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area are collected to generate thermal stress wave functions and deformation rates, respectively, and the real-time thermal stress value is calculated based on the thermal stress wave functions, including: Real-time acquisition of three-dimensional temperature gradient field in the borehole area in Let be the spatial coordinates, t be the time variable, and a thermal stress wave function be generated based on the three-dimensional temperature gradient field, wherein the thermal stress wave function... The expression is: Where E is Young's modulus, α is the coefficient of thermal expansion, v is Poisson's ratio, ω is the characteristic thermal oscillation frequency, and i is the imaginary unit; Surface micro-deformation signals are acquired synchronously, and the deformation rate is calculated based on the surface micro-deformation signals, wherein the formula for calculating the deformation rate is: in Let δ(t) be the deformation rate, Δt be the time differential step size, and δ(t) and δ(t+Δt) be the deformation at time t and time (t+Δt), respectively. The real-time thermal stress value is calculated based on the thermal stress wave function, wherein the formula for calculating the real-time thermal stress value is: Where σ th Represents the real-time thermal stress value, where Re[·] represents the real part.

4. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 3, characterized in that, The method of triggering a deformation warning and generating a deformation abrupt change region based on the surface micro-deformation signal and the deformation rate when a preset condition is met includes: Based on the deformation rate and surface micro-deformation signal, a triple criterion is calculated, which includes: Temporal abrupt change criterion: Where v0 is the average deformation rate of the current drilling cycle. Statistical deviation criterion: Where MA(δ,t-10) is the moving average of the deformation over the previous 10ms. Frequency domain energy criterion: Where η0 is the average proportion of frequency band energy in historical processing, and FFT[δ(f)] is the Fourier transform of the deformed signal. The energy range is from 10 to 50 kHz. Total energy across the entire frequency band; When the time-domain abrupt change criterion C1, the statistical deviation criterion C2, and the frequency-domain energy criterion C3 are all satisfied simultaneously, a deformation abrupt change warning is triggered, and the coordinate set of the deformation abrupt change region is output, wherein the coordinate set Ω of the deformation abrupt change region is... risk Represented as: Where δ0 is the dynamic deformation threshold, and δ0=1.5×MA(δ,t-10), For position The deformation at time t.

5. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 4, characterized in that, The step of generating a compensated phase distribution based on the thermal stress wavefunction using a spatial light modulator, and driving the compensated beam to modulate the phase of the abrupt deformation region according to the compensated phase distribution to generate a transient modulated stress field, includes: A compensated phase distribution is generated based on the thermal stress wavefunction. Where arg(·) is the argument function of the complex number; When a deformation warning is triggered, the spatial light modulator will be driven to compensate for the phase distribution. Focusing on the set of coordinates Ω of the region of abrupt deformation risk The compensation beam is distributed according to the compensation phase. The coordinate set Ω of the deformation abrupt region risk To conduct intervention and regulation; The coordinate set Ω of the compensation beam and the main beam in the abrupt deformation region risk Destructive interference generates a transient modulated stress field. And satisfy 6. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 5, characterized in that, The formula for calculating the margin coefficient k is as follows: Where d current d represents the current drilling depth. target T represents the target borehole depth in the material parameters. melt The softening point is a parameter in the material specifications. This represents the maximum modulus of the three-dimensional temperature gradient field throughout the entire borehole region.

7. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 6, characterized in that, The implementation of the hierarchical control includes: If σ th <k·σ critical The pulse energy of the main laser is increased by a preset multiple. If σ th ≥k·σ critical Turn on the helium cooling system and reduce the current scanning speed according to the preset ratio.

8. The method for real-time control of thermal stress in laser drilling of glass substrates according to claim 2, characterized in that, The correction formula for the margin coefficient is: k new =k-0.05ΔN; Where ΔN is the stripe order, k new This is the corrected margin factor.

9. A real-time thermal stress control system for laser drilling of glass substrates, used to execute a real-time thermal stress control method for laser drilling of glass substrates as described in any one of claims 1 to 8, and configured with a main laser device for generating a main beam, a laser compensation device for generating a compensation beam, and a spatial light modulator coupled in the optical path of the laser compensation device, characterized in that, The system also includes: The parameter calculation module is used to generate thermal stress wave function and deformation rate based on the three-dimensional temperature gradient field and surface micro-deformation signal of the borehole area, respectively, and calculate the real-time thermal stress value according to the thermal stress wave function. The deformation early warning module is used to trigger a deformation early warning and generate a deformation abrupt change region when preset conditions are met, based on the surface micro-deformation signal and the deformation rate. The phase modulation module is used to generate a compensation phase distribution based on the thermal stress wave function through a spatial light modulator, and drive the compensation beam to perform phase modulation on the deformation abrupt region according to the compensation phase distribution to generate a transient modulated stress field. The dynamic hierarchical control module is used to calculate the margin coefficient based on the three-dimensional temperature gradient field, the current drilling depth acquired in real time, and the material parameters of the pre-loaded glass substrate, and to implement hierarchical control in combination with the margin coefficient and the real-time thermal stress value.

10. A real-time thermal stress control system for laser drilling of glass substrates according to claim 9, characterized in that, The control system also includes: The coefficient correction module is used to measure the fringe level of the transient modulated stress field in the deformation abrupt region, and to correct the margin coefficient when the fringe level meets the preset correction conditions.

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