A substrate air flotation platform control method and system

Abstract

The present invention discloses a substrate air flotation platform control method and system, belonging to the field of novel display technology. The present invention takes into account that for large-area substrate air flotation support systems, precise detection, control, and monitoring are required to ensure the accuracy of continuous substrate air flotation operation. Therefore, the present invention considers the use of laser displacement sensors and force hammers for excitation and signal acquisition, and obtains the natural frequency of the substrate and the vertical height between the bottom surface of the substrate and the air flotation support surface through data processing to adjust the positive and negative pressure of the air flotation platform, detect and control the accuracy of the substrate air flotation platform, and use the laser displacement sensor to determine the operating status of the air flotation platform in real time during continuous operation. In this way, the precision of large-area, high-precision display panel air flotation continuous transportation can be guaranteed to be stable, measurable, controllable, and adjustable, and is particularly suitable for the use of inkjet printing to manufacture high-resolution, large-format displays, electronic components, etc.

Description

Technical Field

[0001] The present invention belongs to the field of novel display technology, and specifically discloses a substrate air floating platform control method and system. Background Art

[0002] Inkjet printing, as an additive manufacturing process, offers significant advantages for display panel manufacturing. It can precisely fill organic solvents into substrate pixel pits, saving over 90% of functional materials. Its high degree of manufacturing flexibility, simplicity, and adaptability make it particularly suitable for the manufacture of large-area, high-precision panels, offering significant advantages over the currently widely used vapor deposition process. Improving the yield rate of printed substrates produced using inkjet printing and promoting its mass production are the goals of panel manufacturers and research institutions worldwide.

[0003] Substrate air-floating supports enable contactless movement of display panels, thus preventing panel defects caused by contact. However, high-precision display panels require high precision, necessitating precise inspection and adjustment of the substrate air-floating platform's accuracy to prevent production failures caused by a drop in accuracy during operation. This can further improve the yield of printed display substrates and promote their mass production application.

[0004] Existing patent CN113424303A describes a device, system, and method for controlling the floating of a substrate, but only describes the structural and control design scheme, without focusing on how to evaluate, detect, and control the sustained stability of the accuracy of the flotation platform; patent CN112888572A describes a substrate conveying method that uses non-vertical airflow to move the substrate on the flotation plane. Obviously, this method cannot be applied to high-precision production occasions.

[0005] In general, the existing technology only focuses on the structural design of the substrate flotation platform, but does not propose effective continuous precision control, detection, and adjustment methods; at the same time, the designed and proposed solutions are mostly aimed at low-precision processing occasions, and are obviously not applicable in higher-precision applications; there is no effective solution to further improve the ultimate performance of the flotation platform. Summary of the Invention

[0006] In response to the defects and improvement needs of the existing technology, the present invention provides a substrate flotation platform control method and system, aiming to solve the problem that the existing substrate flotation platform control method is unstable and cannot be applied to high-precision production.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a method for controlling a substrate air flotation platform, comprising the following steps:

[0008] S1, select several excitation points and response points on the substrate, sequentially excite each excitation point with external force, collect displacement data of each response point, and fit the corresponding impulse response function;

[0009] S2, performing Fourier transform on the impulse response function to obtain a frequency response function, and further calculating the natural frequency of the substrate;

[0010] S3, measuring the vertical height between the bottom surface of the substrate and the air bearing support surface at each excitation point;

[0011] S4, by comparing the natural frequency calculated by S2 with the standard natural frequency, adjust the negative pressure of the air float support; by comparing the vertical height measured by S3 with the standard vertical height, adjust the positive pressure of the air float support;

[0012] S5, measuring the vertical height between the bottom surface of the substrate and the air-floating support surface during continuous operation. If the deviation from the standard vertical height exceeds a threshold, the process jumps to S1.

[0013] Furthermore, in S1, the response points are distributed on an asymmetric axis away from the adsorption end, and the number of response points is M, M≥1; the excitation points are evenly distributed on the substrate, and the number of excitation points is N, N≥2;

[0014] During the excitation process, a force hammer with a soft hammer head is used to strike N excitation points in sequence.

[0015] Furthermore, in S2, the frequency response function of the mth response point to the nth excitation point [H(w)] mn :

[0016]

[0017] Wherein, m=1,...,M,n=1,2,...,N,mn is a subscript; A r For the remainder, A r The conjugate of λ r is the corresponding r-order modal frequency, that is, the natural frequency, and Q is the number of modes to be calculated.

[0018] Furthermore, the S4 includes:

[0019] For the first Q-order natural frequencies λ1,λ2,...,λ calculated for S2 Q , if any 1≤i≤Q satisfies Then increase the negative pressure of the air float support; if any 1≤i≤Q satisfies Then reduce the negative pressure of the air float support or do not perform any treatment;

[0020] For the vertical heights h1,h2,...,h measured by S3 P, if any 1≤k≤P satisfies h k ≥h0, then reduce the positive pressure of the air float support; if any 1≤k≤P satisfies h k ≤h0, then increase the positive pressure of the air float support;

[0021] Repeat the above process until any 1≤i≤Q is satisfied And for any 1≤k≤P, |h k -h0|<ε2;

[0022] in, is the i-th order standard natural frequency, h0 is the standard vertical height, ε1 and ε2 are the allowable deviations of the natural frequency and vertical height respectively.

[0023] Furthermore, the standard order natural frequency is calculated by finite element method. Specifically, the adsorption end is set as the fixed support boundary, the bottom surface of the substrate is set as the elastic support boundary, and the rest are free boundaries. The physical parameters of the substrate are set to be consistent with the actual parameters of the substrate. The standard order natural frequency is calculated.

[0024] Furthermore, the S1 further includes: setting a response signal sampling frequency and an excitation signal sampling frequency, and the response signal sampling frequency RF and the excitation signal sampling frequency SF meet the following requirements:

[0025] RF≥2f s

[0026]

[0027] Among them, f s is the highest frequency of the signal to be sampled, and D is the number of sampling times during the duration of the force pulse signal.

[0028] Furthermore, the S1 further includes: using the coherence function γ xh (f) Verify the correlation between the response signal and the stimulus signal:

[0029]

[0030] Among them, P xx (f) is the autopower spectrum of the hammer excitation signal x(t), P hh (f) is the autopower spectrum of the impulse response function h(t) of the response point, P xh (f) is the cross power spectrum of x(t) and h(t).

[0031] In a second aspect, the present invention further provides a substrate air flotation platform control system, comprising: a laser displacement sensor, a force hammer, a collector, a processing module, and a control module;

[0032] The hammer is used to sequentially excite each excitation point;

[0033] The laser displacement sensor is used to obtain the displacement data of each response point and the vertical height between the bottom surface of the substrate and the air-floating support surface at each excitation point, and store the data through the acquisition instrument;

[0034] The processing module obtains an impulse response function based on the displacement data of each response point by fitting, and obtains a frequency response function by Fourier transforming the impulse response function, and further calculates the natural frequency of the substrate;

[0035] The control module adjusts the negative pressure of the air float support by comparing the calculated natural frequency with the standard natural frequency; and adjusts the positive pressure of the air float support by comparing the measured vertical height with the standard vertical height.

[0036] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0037] (1) The innovation of the present invention lies in the discovery that the natural frequency of the substrate is positively correlated with the stiffness of the substrate air-floating support. Therefore, it is proposed to characterize the stiffness of the substrate air-floating support by calculating the natural frequency of the substrate, thereby adjusting the negative pressure of the air-floating support. Specifically, an external force is used to excite the excitation point on the substrate, and displacement data is collected at the response point. The natural frequency of the substrate is obtained by data processing. At the same time, the vertical height between the bottom surface of the substrate and the air-floating support surface at each excitation point is measured to adjust the positive pressure of the air-floating support, thereby achieving parameter adjustment of the substrate air-floating platform. In addition, the operating status of the air-floating platform is determined in real time during continuous operation to detect and control the accuracy of the substrate air-floating platform. In this way, the accuracy of the large-area, high-precision display panel air-floating continuous transportation can be guaranteed to be stable, measurable, controllable and adjustable, and is particularly suitable for the use of inkjet printing to manufacture high-resolution, large-format displays, electronic components, etc.

[0038] (2) In the present invention, the response points are distributed on the asymmetric axis away from the adsorption end, and the excitation points are evenly distributed on the substrate, which can make the test more accurate and measure all natural frequencies with fewer excitation times. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is an operational flow chart of a substrate air flotation platform control method provided by the present invention;

[0040] Figure 2 This is the excitation point and response point selection diagram provided by the present invention;

[0041] Figure 3 This is one of the flow charts of the solution provided by the present invention;

[0042] Figure 4 This is the second flow chart of the solution provided by the present invention;

[0043] Figure 5 It is a system structure diagram provided by the present invention. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0045] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0046] The present invention's controlled substrate air flotation platform consists of a substrate, substrate adsorption strips, a motion motor, and air flotation support blocks. The air flotation support blocks are evenly distributed on the substrate's bottom surface, providing stable support for the substrate. The substrate adsorption strips secure the substrate at one end, while the motion motor drives the substrate adsorption strips, achieving contactless movement of the substrate on the air flotation support blocks.

[0047] See Figure 1 , combined with Figures 2 to 4 The present invention provides a substrate air floating platform control method, including operations S1 to S5.

[0048] In operation S1 , a number of excitation points and response points are selected on the substrate, each excitation point is sequentially excited by an external force, displacement data of each response point is collected, and a corresponding impulse response function is obtained by fitting.

[0049] Before printing, the sampling frequencies of the excitation signal and the response signal need to be set. For the selection of the signal sampling frequency, the sampling frequency RF of the response signal and the sampling frequency SF of the excitation signal should meet the following requirements:

[0050] RF≥2f s

[0051]

[0052] Among them, f s is the maximum frequency of the signal to be sampled, and D is the number of measurement samples during the duration of the force pulse signal. The response signal sensor is a laser displacement sensor, and the excitation signal is a force hammer (equipped with a soft hammer head). The laser displacement sensor and force hammer are connected to a signal acquisition instrument, which collects data from the laser displacement sensor and force hammer and transmits it to a host PC for display and processing.

[0053] The selection of the hammer excitation point and the laser displacement sensor observation response point is as follows: Figure 2 As shown, the response point of the substrate should be selected on the asymmetric axis away from the adsorption end, the number of reference points is recorded as M (M≥1), the excitation points should be evenly distributed on the substrate, the number of excitation points is N (N≥2), and during the excitation process, a force hammer with a soft hammer head is used to knock N excitation points in turn. Each excitation point is knocked multiple times to ensure accurate data sampling. At the same time, it should be ensured that the response signal of the previous knock is completely attenuated before the next knock is performed to avoid continuous knocks, and the laser displacement sensor is used to collect the signal of the response point simultaneously.

[0054] After the hammer test is completed, the experimental test results need to be fully verified. At this time, the coherence function γ xh (f) Verification:

[0055]

[0056] Among them, P xx (f) is the autopower spectrum of the hammer excitation signal x(t), P hh (f) is the autopower spectrum of the impulse response function h(t) of the response point, P xh (f) is the cross power spectrum of x(t) and h(t), if γ xy ≈1 means that the experimental test results are accurate. If there is a large deviation, repeated experiments and experimental condition checks are needed to ensure the credibility of the results.

[0057] In operation S2, Fourier transform is performed on the impulse response function to obtain a frequency response function, and the natural frequency of the substrate is further calculated.

[0058] The laser displacement sensor acquisition signal and the hammer excitation signal data are processed by the host computer PC to obtain the response-excitation impulse response function h(t). The frequency response function H(w) is obtained by Fourier transforming h(t):

[0059]

[0060] In the process of multiple experiments and multiple excitations, the following method can be used to more accurately measure the frequency response function [H(w)] of the mth response point to the nth excitation point through parameter fitting: mn :

[0061]

[0062] Wherein, m=1,...,M,n=1,2,...,N,m·n are subscripts; A r For the remainder, A r The conjugate of λr is the corresponding r-order modal frequency, that is, the natural frequency, and Q is the number of modes to be calculated.

[0063] In operation S3 , the vertical height between the bottom surface of the substrate and the air bearing support surface at each excitation point is measured.

[0064] In this embodiment, a laser displacement sensor suspended above the substrate is used to measure the vertical height between the bottom surface of the substrate and the air bearing support surface at each excitation point.

[0065] Operation S4: adjusting the negative pressure of the air floating support by comparing the natural frequency calculated by S2 with the standard natural frequency; and adjusting the positive pressure of the air floating support by comparing the vertical height measured by S3 with the standard vertical height.

[0066] For the first Q-order natural frequencies λ1,λ2,...,λ calculated for S2 Q , if any 1≤i≤Q satisfies This means that the air film stiffness of the air floating support is less than the target value, and the negative pressure of the air floating support needs to be further increased; if any 1≤i≤Q satisfies This indicates that the air film stiffness of the air float support is greater than the target value, meeting the stiffness requirement, and there is a certain adjustment space for the air float negative pressure, that is, the air float negative pressure can be reduced or not treated;

[0067] For the vertical heights h1,h2,...,h measured by S3 P , if any 1≤k≤P satisfies h k ≥h0, it means that the air film pressure of the air float support is too large, and the positive pressure of the air float support needs to be reduced; if any 1≤k≤P satisfies h k If h0 is less than or equal to h0, it means that the air film pressure of the air float support is too low and the positive pressure of the air float support needs to be increased.

[0068] Repeat the above process until any 1≤i≤Q is satisfied And for any 1≤k≤P, |h k -h0|<ε2;

[0069] in, is the i-th order standard natural frequency, h0 is the standard vertical height, ε1 and ε2 are the allowable deviations of the natural frequency and vertical height respectively.

[0070] It's important to note that the flow rate characteristics of each air float block must be calibrated before use. When the air float blocks are properly installed, the baseplate's natural frequency and the vertical height between the baseplate and the air float support surface will only be greater than or less than the standard value. If other conditions occur during use, it indicates an uneven support air film. Check the air float blocks for proper installation and any performance degradation with continued use. Adjust the throttle or pressure valve of each block individually.

[0071] Regarding the acquisition of standard values ​​that need to be compared with experimental data, on the one hand, empirical test data can be used for judgment and adjustment; on the other hand, the acquisition of standard order natural frequency can be achieved by finite element calculation. In the finite element method, the adsorption end is set as the fixed support boundary, the bottom surface of the substrate is the elastic support boundary, and the rest are free boundaries. The physical parameters of the substrate are set to be consistent with the actual parameters of the substrate, and the standard order natural frequency is calculated.

[0072] Operation S5 : measuring the vertical height between the bottom surface of the substrate and the air bearing support surface during continuous operation. If the deviation from the standard vertical height exceeds a threshold, the process jumps to S1 .

[0073] After the experimental test and adjustment process is completed, during the continuous operation of the air flotation platform, the laser displacement sensor is suspended at a fixed distance above the substrate to measure the vertical height between the bottom surface of the continuously running substrate and the air flotation support surface. If the actual measured value during the continuous operation deviates significantly from the standard value in the test phase, the air flotation platform needs to be inspected and readjusted.

[0074] It should be noted that operation S5 is for a continuously operating substrate flotation platform, while operations S1 to S4 need to be performed offline.

[0075] The present invention also provides a substrate air flotation platform control system, comprising: a laser displacement sensor, a force hammer, a collector, a processing module and a control module;

[0076] The hammer is used to sequentially excite each excitation point;

[0077] The laser displacement sensor is used to obtain the displacement data of each response point and the vertical height between the bottom surface of the substrate and the air-floating support surface at each excitation point, and store the data through the acquisition instrument;

[0078] The processing module obtains an impulse response function based on the displacement data of each response point by fitting, and obtains a frequency response function by Fourier transforming the impulse response function, and further calculates the natural frequency of the substrate;

[0079] The control module adjusts the negative pressure of the air float support by comparing the calculated natural frequency with the standard natural frequency; and adjusts the positive pressure of the air float support by comparing the measured vertical height with the standard vertical height.

[0080] like Figure 5 As shown, the present invention also provides an overall system including a substrate flotation platform and a control system, wherein 1 represents a PC, 2 represents a collector, 3 represents a force hammer, 4 represents a laser displacement sensor, 5 represents a motor, 6 represents a glass substrate, 7 represents an air flotation positive pressure zone, and 8 represents an air flotation negative pressure adsorption hole.

[0081] In summary, the innovation of this invention lies in the discovery that the natural frequency of the substrate is positively correlated with the stiffness of the substrate's air bearing support. Consequently, the invention proposes characterizing the stiffness of the substrate's air bearing support by calculating the substrate's natural frequency, thereby adjusting the negative pressure of the air bearing support. Simultaneously, the positive pressure of the air bearing support is adjusted by measuring the vertical height between the substrate bottom surface and the air bearing surface at each excitation point, thereby enabling parameter adjustment of the substrate's air bearing platform. This ensures the precision, stability, measurability, controllability, and adjustability of continuous air bearing transport for large-area, high-precision display panels. This approach is particularly suitable for the manufacture of high-resolution, large-format displays and electronic components using inkjet printing.

[0082] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling a substrate air flotation platform, characterized in that: The following steps are involved: S1, select several excitation points and response points on the substrate, sequentially stimulate each excitation point with external force, collect displacement data of each response point, and fit the corresponding impulse response function; S2, performing Fourier transform on the impulse response function to obtain a frequency response function, and further calculating the natural frequency of the substrate; S3, measuring the vertical height between the bottom surface of the substrate and the air bearing support surface at each excitation point; S4, by comparing the natural frequency calculated by S2 with the standard natural frequency, adjust the negative pressure of the air float support; by comparing the vertical height measured by S3 with the standard vertical height, adjust the positive pressure of the air float support; S5, measuring the vertical height between the bottom surface of the substrate and the air-floating support surface during continuous operation. If the deviation from the standard vertical height exceeds a threshold, the process jumps to S1.

2. A substrate air flotation platform control method according to claim 1, characterized in that: In S1, the response points are distributed on an asymmetric axis away from the adsorption end, and the number of response points is M, M ≥ 1; the excitation points are evenly distributed on the substrate, and the number of excitation points is N, N ≥ 2; During the excitation process, a force hammer with a soft hammer head is used to strike N excitation points in sequence.

3. A substrate air flotation platform control method according to claim 2, characterized in that: In S2, the frequency response function of the mth response point to the nth excitation point [H(w)] m·n : Wherein, m=1,...,M,n=1,2,...,N,m·n are subscripts; A r For the remainder, A r The conjugate of λ r is the corresponding r-order modal frequency, that is, the natural frequency, and Q is the number of modes to be calculated.

4. A substrate air flotation platform control method according to claim 3, characterized in that: The S4 includes: For the first Q-order natural frequencies λ1,λ2,...,λ calculated for S2 Q , if any 1≤i≤Q satisfies Then increase the negative pressure of the air support; if any 1≤i≤Q satisfies Then reduce the negative pressure of the air float support or do not perform any treatment; For the vertical heights h1,h2,...,h measured by S3 P , if any 1≤k≤P satisfies h k ≥h0, then reduce the positive pressure of the air float support; if any 1≤k≤P satisfies h k ≤h0, then increase the positive pressure of the air float support; Repeat the above process until any 1≤i≤Q is satisfied And for any 1≤k≤P, |h k -h0|<ε2; in, is the i-th order standard natural frequency, h0 is the standard vertical height, ε1 and ε2 are the allowable deviations of the natural frequency and vertical height respectively.

5. A substrate air flotation platform control method according to claim 1 or 4, characterized in that: Finite element method is used to calculate the standard order natural frequency. Specifically, the adsorption end is set as the fixed support boundary, the bottom surface of the substrate is the elastic support boundary, and the rest are free boundaries. The physical parameters of the substrate are set to be consistent with the actual parameters of the substrate. The standard order natural frequency is calculated.

6. The substrate air flotation platform control method according to claim 1, wherein: The step S1 further includes setting a response signal sampling frequency and an excitation signal sampling frequency, wherein the response signal sampling frequency RF and the excitation signal sampling frequency SF meet the following requirements: RF≥2f s Among them, f s is the highest frequency of the signal to be sampled, and D is the number of sampling times during the duration of the force pulse signal.

7. The substrate air flotation platform control method according to claim 1, wherein: Said S1 also includes: through the coherence function γ xh (f) Verify the correlation between the response signal and the stimulus signal: Among them, P xx (f) is the autopower spectrum of the hammer excitation signal x(t), P hh (f) is the autopower spectrum of the impulse response function h(t) of the response point, P xh (f) is the cross power spectrum of x(t) and h(t).

8. A substrate air flotation platform control system, characterized in that: include: Laser displacement sensor, force hammer, data acquisition instrument, processing module and control module; The hammer is used to sequentially excite each excitation point; The laser displacement sensor is used to obtain the displacement data of each response point and the vertical height between the bottom surface of the substrate and the air-floating support surface at each excitation point, and store the data through the acquisition instrument; The processing module obtains an impulse response function based on the displacement data of each response point by fitting, and obtains a frequency response function by Fourier transforming the impulse response function, and further calculates the natural frequency of the substrate; The control module adjusts the negative pressure of the air float support by comparing the calculated natural frequency with the standard natural frequency; and adjusts the positive pressure of the air float support by comparing the measured vertical height with the standard vertical height.

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