An LCD screen printing device with static electricity elimination function

Abstract

This invention provides an LCD screen printing apparatus with electrostatic elimination function, relating to the field of LCD manufacturing. It includes an LCD printing apparatus body and a mounting device. The LCD printing apparatus body includes a squeegee device, and the mounting device includes several connecting frames. Each connecting frame includes a vertical plate and a mounting plate connected to the lower end of the vertical plate. The vertical plate has vertical slotted holes, and the squeegee device has a threaded hole corresponding to the vertical slotted hole. The non-nut section of a screw passes through the vertical slotted hole and connects to the corresponding threaded hole. The mounting plate has non-vertical slotted holes, and the non-nut section of a screw passes through the non-vertical slotted hole and connects to the outer shell of a pulsed electrostatic elimination rod. A control device is electrically connected to both the LCD printing apparatus body and the pulsed electrostatic elimination rod. This invention's connecting frame integrates dual functions of height, horizontal, or angular fine-tuning, is easy to manufacture, requires no large-scale modification of existing printing equipment, and is convenient to install and maintain.

Description

Technical Field

[0001] This invention relates to the field of LCD (liquid crystal display) manufacturing technology, specifically to an LCD screen printing apparatus with electrostatic elimination function. Background Technology

[0002] In LCD manufacturing, screen printing is a crucial process, primarily used to print alignment layers, conductive silver paste, and other functional materials onto the surface of a glass substrate. However, at the moment the screen separates from the substrate after printing, strong static electricity is generated due to the rapid peeling and friction between the two. This static electricity can cause the following problems:

[0003] 1. Adsorption of contaminants: Static electricity can attract dust and particles from the surrounding environment, causing defects in printed patterns and reducing product yield.

[0004] 2. Pattern deformation: Static electricity may disturb the incompletely cured printing paste, causing the pattern edges to become blurred and the lines to become deformed.

[0005] 3. Damage to ITO substrate: High-intensity static electricity during separation can directly damage the substrate, leading to substrate defects.

[0006] 4. Equipment damage: Long-term accumulation of static electricity may damage the delicate electronic components of the equipment and even cause safety hazards.

[0007] 5. Personnel safety: High voltage static electricity may cause electric shock to operators.

[0008] Existing screen printing static elimination devices, such as the LCD circuit board printing device with synchronous static elimination disclosed in CN214294976U, have the following problems:

[0009] The static eliminator is fixed on the same synchronous bracket as the squeegee, and can only move horizontally with the squeegee. It cannot be adjusted in height or horizontal distance from the squeegee to meet different printing needs. Summary of the Invention

[0010] The present invention provides an LCD screen printing apparatus with static electricity elimination function to solve the technical problems mentioned in the background art.

[0011] To solve the above-mentioned technical problems, the present invention discloses an LCD screen printing apparatus with electrostatic elimination function, comprising an LCD printing apparatus body, the LCD printing apparatus body including a squeegee device, characterized in that: the LCD screen printing apparatus further includes:

[0012] Installation device: includes several connecting frames, each connecting frame including a vertical plate and a mounting plate connected to the lower end of the vertical plate. The vertical plate is provided with vertical strip holes, and the scraper device is provided with a threaded hole corresponding to the vertical strip holes. The non-nut section of screw one passes through the vertical strip holes and is connected to the corresponding threaded hole one. The mounting plate is provided with non-vertical strip holes, and the non-nut section of screw two passes through the non-vertical strip holes and is connected to the outer shell of the pulse static electricity eliminator.

[0013] The control device is electrically connected to the LCD printing device body and the pulse static elimination rod.

[0014] Preferably, the LCD printing apparatus body also includes:

[0015] A printing table, with a printing platform at the top and a workpiece placement seat on the printing platform;

[0016] Lifting device one is installed on the upper part of the printing table platform and is located behind the workpiece placement seat. The lifting end of lifting device one is connected to a connecting seat. The connecting seat is connected to a left and right translation device. The moving end of the left and right translation device is connected to lifting device two. The lifting end of lifting device two is connected to a scraper device. The scraper device includes lifting device three. Lifting device three is connected to the lifting end of lifting device two. The lifting end of lifting device three is connected to a scraper.

[0017] The connecting frame is connected to the connecting seat, and the scraper is located inside the connecting frame;

[0018] A screen printing stencil, which is connected to the inside of the connecting frame.

[0019] Preferably, the length direction of the non-vertical strip hole is the left-right direction.

[0020] Preferably, the connecting frame is connected to the forward direction side of the doctor blade device along the printing motion direction.

[0021] Preferably, the distance between the installation position of the pulse static eliminator and the doctor blade along the printing movement direction is 5-15cm.

[0022] Preferred options also include:

[0023] Storage device: Stores a reference mapping model, which is the ideal ionization parameter range corresponding to each commonly used squeegee printing speed range under the corresponding theoretical printing pressure conditions of the reference LCD substrate;

[0024] Speed ​​detection device: used to detect the printing speed of the squeegee;

[0025] Electrostatic discharge (ESD) detection device: used to detect the surface electrostatic voltage of the LCD substrate after ionization following screen printing testing;

[0026] Displacement detection device: used to detect the distance the doctor blade moves along the printing direction;

[0027] The control device includes: a test control module, which includes:

[0028] Process parameter acquisition unit: acquires the theoretical printing pressure range and the theoretical squeegee printing speed under non-static elimination state of the substrate under test;

[0029] Measurement and control unit 1: Select multiple test speeds within the theoretical squeegee printing speed range, and control the left and right translation device to start and stably run to each test speed. Based on the displacement data of the squeegee along the printing direction detected by the displacement detection device, determine the stable displacement corresponding to each test speed.

[0030] Analysis Unit 1: Used to determine several matching ideal ionization parameter ranges from the reference mapping model based on the theoretical squeegee printing speed of the substrate under test; and to generate several test parameter sets based on the median of the theoretical printing pressure range, the median of the theoretical squeegee printing speed, and the median of each matching ideal ionization parameter range of the substrate under test.

[0031] Measurement and control unit 2: Used to control the silkscreen printing test of the test substrate based on each test parameter group;

[0032] Analysis Unit Two: Used to determine the current target ionization parameters based on the detection results of the screen printing test control process based on Measurement and Control Unit Two and the stable displacement corresponding to each test speed.

[0033] Preferably, the control device is connected to the storage device, the speed detection device, the electrostatic detection device, and the displacement detection device via signals.

[0034] Preferably, the determining unit includes:

[0035] Analysis Sub-unit 1: Based on the detection results of the screen printing test control process of measurement and control unit 2, construct a matrix of "test squeegee printing speed - ionization parameter - ionization detection device detection value" and mark the stable displacement corresponding to the test squeegee printing speed.

[0036] Analysis Subunit 2: Used to determine the current target ionization parameters based on the matrix;

[0037] When the substrate to be tested is officially printed in batches, the control device controls the pulse electrostatic eliminator to work based on the current target ionization parameters.

[0038] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

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

[0040] This invention allows for flexible adjustment of the installation height of the pulsed static eliminator rod via vertical slots in the connecting bracket, adapting to printing scenarios with LCD substrates of varying thicknesses and screen tensions, ensuring the ionization distance remains within the optimal range. Through non-vertical slots (which can be horizontal) on the mounting plate, the horizontal relative position of the pulsed static eliminator rod and the squeegee can be precisely adjusted. This allows for simultaneous elimination of frictional static electricity during the printing stage, synchronized with the squeegee, and alignment with the peeling interface during screen separation, achieving full-process static coverage. The pulsed static eliminator rod is detachably mounted on the squeegee device via screws one and two, enabling quick replacement and maintenance of the rod without disassembling the squeegee, thus avoiding impact on printing alignment accuracy. It is compatible with different models and lengths of pulsed static eliminator rods, and the slots allow for adjustment to meet different ionization range requirements. Compared to the existing design of "rigidly binding the static eliminator to the synchronization bracket," this significantly improves the device's versatility and maintainability.

[0041] The control device is electrically connected to the LCD printing unit body and the pulse static eliminator, and can dynamically adjust the activation timing and output intensity of static elimination according to process parameters such as squeegee movement sequence, screen lifting signal, and printing speed.

[0042] The mounting device is directly attached to the doctor blade assembly, eliminating the need for an additional independent transmission mechanism and preventing interference with the normal printing motion and alignment accuracy of the doctor blade. The connecting frame integrates both height and horizontal / angle fine-tuning functions into a single structure. Its simple structure and easy manufacturing eliminate the need for complex precision transmission or control components. Furthermore, the integrated design reduces the number of parts and assembly steps, lowering production costs. No large-scale modifications to existing printing equipment are required, making installation and maintenance convenient.

[0043] After the squeegee device completes one printing cycle, the screen printing plate begins to separate from the glass substrate. At this moment, the pulsed electrostatic eliminator rod installed in front of the squeegee device, triggered by the control device, instantly releases a high-voltage pulse. The air around the pulsed electrostatic eliminator rod generates a large number of positive and negative ion flows. These ion flows quickly reach the printing area, neutralizing the electrostatic charge generated on the surface of the screen printing plate and the glass substrate due to the peeling process. The entire process is matched with the screen printing plate separation action, ensuring that static electricity is effectively eliminated at the first moment it is generated. Attached Figure Description

[0044] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0045] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0046] Figure 2 For the present invention Figure 1A partial right view;

[0047] Figure 3 For the present invention Figure 1 An enlarged schematic diagram of region A.

[0048] In the diagram: 1. LCD printing device body; 11. Squeegee device; 111. Squeegee; 112. Lifting device three; 12. Printing table; 121. Printing platform; 13. Workpiece placement seat; 14. Lifting device one; 15. Lifting device two; 16. Left and right translation device; 17. Screen printing plate; 18. Connecting frame; 19. Connecting seat; 2. Pulse static electricity eliminator; 21. Outer shell; 3. Mounting device; 31. Connecting frame; 311. Vertical plate; 3111. Vertical strip hole; 312. Mounting plate; 3121. Non-vertical strip hole; 313. Screw one; 314. Screw two. Detailed Implementation

[0049] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0050] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0051] The present invention provides the following embodiments:

[0052] Example 1: This embodiment of the invention provides an LCD screen printing apparatus with electrostatic elimination function, such as... Figures 1-3 As shown, it includes:

[0053] The LCD printing apparatus includes an LCD printing device body 1, which includes a squeegee device 11. The LCD screen printing apparatus also includes:

[0054] Mounting device 3: includes several connecting frames 31, each connecting frame 31 including a vertical plate 311 and a mounting plate 312 connected to the lower end of the vertical plate 311. The vertical plate 311 is provided with vertical strip holes 3111, and the scraper device 11 is provided with a threaded hole corresponding to the vertical strip hole 3111. The non-nut section of the screw 313 passes through the vertical strip hole 3111 and is connected to the corresponding threaded hole. The mounting plate 312 is provided with non-vertical strip holes 3121, and the non-nut section of the screw 314 passes through the non-vertical strip holes 3121 and is connected to the outer shell 21 of the pulse static electricity eliminator 2. The diameter of the nuts is larger than the width of the corresponding strip holes.

[0055] The control device is electrically connected to the LCD printing device body 1 and the pulse static elimination rod 2.

[0056] The LCD printing apparatus body 1 also includes:

[0057] Printing table 12, printing platform 121 at the upper end of printing table 12, workpiece placement seat 13 is provided on printing platform 121;

[0058] Lifting device 14 is installed on the upper part of the printing table 12 platform and is located behind the workpiece placement seat 13. The lifting end of lifting device 14 is connected to a connecting seat 19. The connecting seat 19 is connected to a left and right translation device 16 (specifically, the fixed end of the left and right translation device 16). The moving end of the left and right translation device 16 is connected to a lifting device 2 15 (specifically, the fixed end of the lifting device 2 15). The lifting end of lifting device 2 15 is connected to a scraper device 11. The scraper device 11 includes a lifting device 3 112. The lifting device 3 112 (specifically, the fixed end of the lifting device 3 112) is connected to the lifting end of lifting device 2 15. The lifting end of lifting device 3 112 is connected to the scraper 111.

[0059] The connecting frame 18 is connected to the connecting seat 19, and the scraper 111 is located inside the connecting frame 18;

[0060] The screen printing plate 17 is connected to the inside of the connecting frame 18.

[0061] Preferably, the length direction of the non-vertical strip hole 3121 is the left-right direction.

[0062] Preferably, the connecting frame 31 is connected to the forward direction side of the squeegee device 11 along the printing movement direction.

[0063] Preferably, the distance between the installation position of the pulse static eliminator 2 and the doctor blade 111 along the printing movement direction is 5-15cm.

[0064] The LCD printing device body 1 can be an existing LCD printing device, thus enabling the modification of the existing LCD printing device;

[0065] Both the left-right translation device and the lifting device of the present invention can be selected from existing corresponding types of devices;

[0066] The beneficial effects of the above technical solution are as follows:

[0067] This invention allows for flexible adjustment of the installation height of the pulsed static eliminator 2 via the vertical slot 3111 of the connecting bracket 31, adapting to printing scenarios with different LCD substrate thicknesses and screen tensions, ensuring the ionization distance remains within the optimal range. Through the non-vertical slot 3121 (which can be horizontal) of the mounting plate 312, the horizontal relative position of the pulsed static eliminator 2 and the squeegee 111 can be precisely adjusted, enabling synchronous elimination of frictional static electricity during the printing stage and alignment with the peeling interface during the screen separation stage, achieving full-process static electricity coverage. The pulsed static eliminator 2 is detachably mounted on the squeegee device 11 via screw 313 and screw 314, allowing for quick replacement and maintenance of the pulsed static eliminator 2 without disassembling the squeegee 111, thus avoiding impact on printing alignment accuracy. It is compatible with different models and lengths of pulsed static eliminators 2, and the slot adjustment adapts to different ionization range requirements. Compared to the existing design of "rigid binding of the static eliminator and the synchronous bracket," this significantly improves the versatility and maintainability of the device.

[0068] The control device is electrically connected to the LCD printing unit body 1 and the pulse static eliminator 2. It can dynamically adjust the activation timing and output intensity of static elimination according to process parameters such as squeegee movement sequence, screen lifting signal, and printing speed.

[0069] The mounting device 3 is directly attached to the doctor blade device 11, eliminating the need for an additional independent transmission mechanism and preventing interference with the normal printing motion and alignment accuracy of the doctor blade 111. The connecting frame 31 integrates both height and horizontal / angle fine-tuning functions in a single structure. The connecting frame 31 has a simple structure, is easy to manufacture, and requires no complex precision transmission or control components. Furthermore, the integrated design reduces the number of parts and assembly steps, lowering production costs. It also eliminates the need for large-scale modifications to existing printing equipment, making installation and maintenance convenient.

[0070] After the squeegee device 11 completes one printing cycle, the screen printing stencil 17 begins to separate from the glass substrate. At this time, the pulsed static eliminator 2, installed in front of the squeegee device 11, releases a high-voltage pulse instantaneously upon triggering by the control device. The air surrounding the pulsed static eliminator 2 generates a large number of positive and negative ion flows. These ion flows quickly reach the printing area, neutralizing the static charge generated on the screen printing stencil 17 and the glass substrate surface due to the peeling process. The entire process is synchronized with the separation action of the screen printing stencil 17, ensuring that static electricity is effectively eliminated at the first moment it is generated.

[0071] Example 2, based on Example 1, further includes:

[0072] Storage device: Stores a reference mapping model, which is the ideal ionization parameter range corresponding to each commonly used squeegee printing speed range (specifically, the speed at which the squeegee moves along the printing direction during printing) of the reference LCD substrate under the corresponding theoretical printing pressure conditions.

[0073] Speed ​​detection device: used to detect the printing speed of the squeegee;

[0074] Electrostatic discharge (ESD) detection device: used to detect the surface ESD voltage of the LCD substrate after ionization following screen printing testing (ESD voltage detection is completed within 10 seconds after screen printing is completed).

[0075] Displacement detection device: used to detect the distance the doctor blade moves along the printing direction;

[0076] The control device includes a test control module (used for testing and verification when substrate printing is required; it can be performed once per batch when there are large differences between product batches; it can also be used to determine the performance of new models with deviations in substrate thickness, etc.). The test control module includes:

[0077] Process parameter acquisition unit: acquires the theoretical printing pressure range and the theoretical squeegee printing speed under non-static elimination state of the substrate under test;

[0078] Measurement and control unit 1: Select multiple test speeds within the theoretical squeegee printing speed range, and control the left and right translation device to start and stabilize at each test speed. Based on the displacement data of the squeegee along the printing direction detected by the displacement detection device, determine the stable displacement corresponding to each test speed.

[0079] Analysis Unit 1: Used to determine several matching ideal ionization parameter ranges from the reference mapping model based on the theoretical squeegee printing speed of the substrate under test; and to generate several test parameter sets based on the median of the theoretical printing pressure range, the median of the theoretical squeegee printing speed, and the median of each matching ideal ionization parameter range of the substrate under test.

[0080] Measurement and control unit 2: Used to control the silkscreen printing test of the test substrate based on each test parameter group;

[0081] Analysis Unit 2 is used to determine the current target ionization parameters based on the detection results of the screen printing test control process of Measurement and Control Unit 2 and the stable displacement corresponding to each test speed.

[0082] The control device is connected to the storage device, speed detection device, electrostatic detection device, and displacement detection device respectively, and is used to acquire the detection data of each device and output control commands.

[0083] The determining unit includes:

[0084] Analysis Sub-unit 1: Based on the detection results of the screen printing test control process of measurement and control unit 2, construct a matrix of "test squeegee printing speed - ionization parameter - ionization detection device detection value" and mark the stable displacement corresponding to the test squeegee printing speed.

[0085] Analysis Subunit 2: Used to determine the current target ionization parameters based on the matrix;

[0086] When the substrate to be tested is officially mass-produced, the control device controls the pulse electrostatic eliminator to work based on the current target ionization parameters (the final optimal ionization parameters directly output the corresponding voltage and frequency values ​​for direct equipment control).

[0087] 1. Storage device related content:

[0088] Theoretical printing pressure: For a specific type of LCD substrate, under all other process conditions such as fixed screen, squeegee, and printing stroke (without considering squeegee printing speed and ionization), printing tests are conducted by adjusting only the squeegee pressure. The initial printing pressure range is determined based on the standard that the printing quality is qualified and the substrate is not damaged. The theoretical printing pressure range is used to further screen the initial printing pressure range (screening sub-ranges that are far from the boundary and stable and reliable).

[0089] For example, if the initial acceptable pressure range is 0.20 to 0.45 MPa, then the theoretical printing pressure range will be narrowed to about 60 to 75% of the middle range.

[0090] The aforementioned storage device is used to solidify a benchmark mapping model for typical operating conditions of the target LCD product series during the R&D phase. This model is not constructed individually for each type and thickness of LCD substrate. Instead, it selects a representative type of LCD substrate, and under the premise of a fixed theoretical printing pressure range, it conducts printing experiments by adjusting parameters such as the output voltage and pulse frequency of the pulse electrostatic eliminator for each squeegee printing speed range commonly used in the production of the target LCD product series. The parameter range that allows the electrostatic potential between the screen printing plate and the substrate to reach the qualified standard is detected and selected; this range is the ideal ionization parameter range corresponding to that speed range. This forms a reusable process matching rule library.

[0091] Typical examples are as follows:

[0092] For a specific type of LCD substrate, with its theoretical printing pressure range of 0.20–0.25 MPa fixed, printing tests were conducted on various squeegee printing speed ranges (0–50 mm / s, 50–100 mm / s, 100–150 mm / s, 150–200 mm / s) commonly used in the production of the target LCD product series. The output voltage and pulse frequency of the pulse electrostatic eliminator were adjusted respectively. The parameter range that ensures the electrostatic voltage between the screen printing plate and the substrate meets ±100V was detected and selected. This range is the ideal ionization parameter range corresponding to each speed range.

[0093] 0~50mm / s (greater than the lower limit and less than or equal to the upper limit): output voltage 4.0~4.5kV, pulse frequency 12~16kHz;

[0094] 50~100mm / s: Output voltage 4.5~5.0kV, pulse frequency 16~20kHz;

[0095] 100~150mm / s: Output voltage 5.0~5.5kV, pulse frequency 20~24kHz;

[0096] 150~200mm / s: Output voltage 5.5~6.0kV, pulse frequency 24~28kHz.

[0097] 2. Relevant content of the process parameter acquisition unit:

[0098] The theoretical printing pressure range and theoretical squeegee printing speed under non-electrostatic elimination conditions of the substrate under test are the range of process parameters determined during the R&D experimental phase of the substrate under test through a combination of theoretical analysis (which can be determined by mechanical simulation and comparison with mature process data of the same series to determine a pressure range) and printing experiments.

[0099] The theoretical printing pressure range is a pressure range determined for this type of substrate under test. Under the premise of fixed screen, squeegee, printing stroke and other process conditions (without considering the influence of printing speed and electrostatic elimination), printing tests are carried out by only gradually adjusting the squeegee pressure. The qualified standard is that the printed pattern is complete and clear, and there are no indentations or damage to the ITO layer on the substrate.

[0100] The theoretical doctor blade printing speed under non-static elimination state is a commonly used speed range in production, determined by turning off the static elimination device and only adjusting the doctor blade printing speed gradient to conduct printing tests, with the standard being that the printing quality is qualified and meets the production efficiency requirements.

[0101] 3. Measurement and control unit 1: The measurement and control unit 1 first calls the process parameters to obtain the theoretical squeegee printing speed (hereinafter referred to as the theoretical speed range) of the substrate to be tested output by the unit, and selects multiple test speeds within the theoretical speed range according to equal gradient division or process experience range;

[0102] Each test speed and the allowable threshold for speed fluctuation (e.g., ±2mm / s) are pre-sent to the drive module of the left and right translation device to complete the pre-configuration of the test speed parameters.

[0103] The measurement and control unit sends a start command to the left and right translation device, controlling the scraper device to move along the printing direction to the current target test speed. It also provides real-time feedback on the actual movement speed of the scraper through a speed detection device, executing closed-loop speed control: if the difference between the actual speed and the test speed is greater than a preset fluctuation threshold, the drive parameters of the left and right translation device are immediately adjusted until the actual speed stabilizes within the range of the test speed ± fluctuation threshold. When the actual speed continuously and stably meets the standard for a duration ≥ the preset stabilization duration (which can be adjusted according to the equipment's response characteristics, with a suggested range of 300–800 ms, such as 500 ms), it is determined that the speed has stabilized and enters the displacement data acquisition stage. The moment when the actual scraper speed first enters the range of "target test speed ± 2 mm / s" and remains stable for the full preset stabilization duration is taken as the timing endpoint. The cumulative displacement from the timing start point (the moment the scraper device starts and begins to move along the printing direction) to the timing endpoint is calculated, which is the stable displacement at that test speed. The acquired displacement data is filtered for validity: abnormal discrete values ​​caused by mechanical vibration and sensor interference (such as single-point noise exceeding ± 0.5 mm) are removed. Store the correlation between the test speed and the corresponding stable displacement until the calibration of all test speeds is completed.

[0104] 4. Analysis of relevant content in Unit 1:

[0105] First, based on the key process attributes such as the material and product series of the substrate under test, the corresponding reference LCD substrate in the reference mapping model is matched and located. Then, using the commonly used squeegee printing speed range preset under the reference LCD substrate as the candidate set, the intersection area between each candidate range and the theoretical squeegee printing speed of the substrate under test is calculated, and the intersection area is recorded as the sub-squeegee printing speed range. Each sub-squeegee printing speed range corresponds to the ideal ionization parameter (ionization parameter, including ionization voltage and pulse frequency) range pre-stored in the reference mapping model (recorded as the matching ideal ionization parameter range).

[0106] Based on the median of the theoretical printing pressure range and the median of the theoretical squeegee printing speed of the substrate under test, for each matching ideal ionization parameter range, at least three sets of low / medium / high voltage-frequency gradient combinations (such as 4.0kV-12kHz, 4.2kV-14kHz, 4.5kV-16kHz) are selected to generate several test parameter sets.

[0107] Each squeegee printing speed range corresponds to at least 3 sets of test parameters to cover the potential optimal combination within the range.

[0108] First, based on the list of key process attributes of the substrate to be tested (substrate material, thickness, TFT process type (a-Si / LTPS / IGZO), product size), match and locate the corresponding reference LCD substrate in the reference mapping model according to the priority of material, thickness, process type, and product size (priority of "material > thickness > process type > product size").

[0109] If the material type difference or thickness deviation between the substrate to be tested and the reference substrate is greater than ±10%, the current reference mapping model is not applicable, and a dedicated reference mapping model needs to be reconstructed for this type of substrate; if the difference is within the allowable range, the reference model parameters are directly matched.

[0110] 5. Analysis of Unit Two Related:

[0111] For each test parameter group, four types of core data are collected and aligned synchronously:

[0112] The test parameter set corresponds to the test squeegee printing speed.

[0113] The ionization parameters corresponding to this test parameter set (i.e., the midpoint of the ideal ionization parameter range, including ionization output voltage and pulse discharge frequency);

[0114] The measurement and control unit determines the stable displacement of the scraper at the test speed (reflecting the smoothness of the printing operation).

[0115] After the screen printing test is completed, the electrostatic voltage on the surface of the LCD substrate is collected by the electrostatic detection device (reflecting the effect of electrostatic elimination).

[0116] Matrix dimension and structure definition:

[0117] Row dimension: Test the printing speed of the squeegee, covering all test speed values;

[0118] Column dimensions: Ionization parameters / ionization control parameters, which can be broken down into "ionization output voltage sub-dimension + pulse discharge frequency sub-dimension", or directly into "voltage-frequency combination parameters" as columns;

[0119] Matrix elements: Store the electrostatic voltage on the LCD substrate surface under the corresponding row (velocity) and column (ionization parameter), and also store the corresponding stable displacement (each test parameter group is associated with the stable displacement corresponding to the test speed closest to its velocity), as an auxiliary evaluation index for printing operation stability.

[0120] Matrix construction and anomaly handling: Fill the corresponding positions in the matrix with the electrostatic voltage and stable displacement of all test samples; only discard samples with stable displacement fluctuation > 0.5 mm or |electrostatic voltage| > ±150 V;

[0121] Stable displacement is the total cumulative displacement of the doctor blade from startup to the speed stabilization stage. It is used to determine whether the displacement in this stage is within the allowable uneven displacement range of the initial stage: If stable displacement ≤ allowable uneven displacement of the initial stage: it means that the displacement deviation of the initial stage is within the acceptable range of the process and will not cause quality defects such as uneven ink layer or pattern offset in the printing stage; If stable displacement > allowable uneven displacement of the initial stage: even if the subsequent operation is stable, the excessive displacement of the initial stage will cause printing quality problems in the front stage. All ionization parameter samples at this speed must be marked as non-compliant with the process.

[0122] Stable displacement timing start point: the moment when the squeegee device starts and begins to move along the printing direction (excluding the time for the zeroing / reset phase); Stable displacement timing end point: the moment when the actual speed of the squeegee first enters the range of "target test speed ±2mm / s" and remains stable for a preset stable duration (300~800ms, which can be adjusted according to the equipment response characteristics); if the speed fluctuation exceeds the range of "target test speed ±2mm / s", timing needs to be restarted; the cumulative displacement from the timing start point to the timing end point is the stable displacement at that test speed; the collected displacement data is filtered for validity: abnormal discrete values ​​caused by mechanical vibration and sensor interference (such as single-point noise exceeding ±0.5mm) are removed.

[0123] The allowable uneven displacement in the initial segment refers to the maximum cumulative displacement deviation that is technologically acceptable during the initial acceleration phase of the scraper from startup to speed stabilization, and is determined in the following way:

[0124] Process verification experiment method: Select a typical reference speed (which can be the common squeegee printing speed of the corresponding reference LCD substrate when obtaining the reference model, such as 0~50mm / s), set the gradient initial segment displacement (0.2mm, 0.5mm, 0.8mm, 1.0mm) for printing test; perform quality inspection on the corresponding area of ​​the substrate after printing, and count the defect rates such as uneven ink layer thickness, pattern offset, and broken lines; take the maximum initial displacement corresponding to the defect rate ≤5% (which can be adjusted according to product requirements) as the allowable uneven displacement of the initial segment in this speed range.

[0125] Historical data statistical method: Extract the initial segment displacement data of qualified products in the past, statistically analyze its distribution pattern (such as normal distribution), and take the upper limit value of displacement corresponding to the 95% confidence interval (that is, the initial segment displacement of 95% qualified products is less than this value) as the allowable uneven displacement of the initial segment.

[0126] Final screening criteria: From the matrix, select ionization parameters that meet the following criteria: "Electrostatic voltage meets ±100V (optimal electrostatic elimination effect); and the total cumulative stable displacement is ≤ the allowable uneven displacement of the initial segment (e.g., 0.5mm), indicating stable printing operation and compliant initial segment process." These will be used as the current target ionization parameters. If the current test group cannot select target control parameters that meet both stable displacement and electrostatic voltage constraints, more test groups will be added to expand the coverage of voltage, frequency, and speed combinations until the target control parameters that meet the requirements are selected.

[0127] The beneficial effects of the above technical solution are as follows:

[0128] Storage devices: Instead of building separate mapping models for every LCD substrate material and thickness, a representative substrate is selected to solidify a baseline mapping model. This significantly reduces the number of printing tests during the R&D phase, shortens the new process introduction cycle, and lowers R&D costs. It also establishes reusable process matching rules for "squeegee speed range - ideal ionization parameter range," providing standardized parameter data for subsequent products in the same series and avoiding repeated trial and error.

[0129] Process parameter acquisition unit: Parameter pre-processing: Before mass production, the theoretical printing pressure range and theoretical squeegee printing speed under non-static elimination state of the substrate to be tested are determined in advance through a combination of theoretical analysis and printing experiments. This defines a scientific and feasible parameter range for subsequent testing and avoids invalid testing.

[0130] Measurement and Control Unit 1: Through closed-loop speed control, the actual moving speed of the squeegee is ensured to remain stable within ±2mm / s of the target test speed, guaranteeing the quality of the front-end printing. This dual limitation of ionization effect and printing quality is applied. Uneven speed in the front end will directly cause the stable displacement of the squeegee from start to steady speed to exceed the allowable range of the process, resulting in quality defects such as uneven ink layer thickness, pattern misalignment, broken or incomplete lines, and blurred or rough edges. At the same time, it will exacerbate frictional static electricity, causing the substrate and screen to stick and be damaged. Such front-end defects cannot be repaired by subsequent processes, directly reducing the screen printing yield of LCD substrates and increasing product scrap costs.

[0131] Analysis Unit 1: Based on the key process attributes of the substrate under test (material, thickness, process type, etc.), it automatically matches and locates the most suitable benchmark mapping model, quickly obtaining the corresponding ideal ionization parameter range and improving test start-up efficiency. For each matched ideal ionization parameter range, at least three sets of low / medium / high voltage-frequency gradient combinations are selected to generate test parameter sets, covering the potential optimal combinations within the range and avoiding insufficient parameter optimization.

[0132] Based on each set of test parameters, the entire screen printing test process is precisely controlled, and four types of core data are collected simultaneously: squeegee printing speed, ionization parameters, stable displacement, and electrostatic voltage on the LCD substrate surface, providing a complete data foundation for subsequent multidimensional analysis.

[0133] Analysis Unit Two: Constructing a matrix of "test squeegee printing speed - ionization parameters - electrostatic detection value - stable displacement" to structure the scattered test data and intuitively present the correlation between various parameters. A dual-dimensional evaluation system of "electrostatic voltage + stable displacement" is established: "Electrostatic voltage ≤ ±100V ensures effective electrostatic elimination, avoiding pattern shift and uneven ink layer caused by electrostatic adsorption between the screen printing plate and the substrate; stable displacement ≤ the allowable uneven displacement of the initial segment (default 0.5mm) ensures the smooth operation of the squeegee, preventing printing defects caused by excessive initial displacement, thus providing dual protection for mass production printing quality." Under these dual constraints, the optimal target ionization parameters are selected to achieve a balance between quality and efficiency. The current target ionization parameters are automatically determined based on matrix data, replacing manual experience-based judgment and improving the accuracy and consistency of parameter selection.

[0134] The entire process, from acquiring process parameters and collecting stable displacement data to generating test parameter sets and matrix screening, is automated, reducing manual intervention and enabling precise process matching for each batch of substrates. This ensures consistency in electrostatic elimination effect and printing quality across different batches of products.

[0135] Example 3, based on Example 1 or 2, further includes:

[0136] Distance detection device: used to detect the vertical distance between a specific position of the squeegee device 11 and the upper surface of the area where the squeegee leaves the screen printing plate 17;

[0137] Timing module: Used to acquire the duration for the pulse electrostatic eliminator 2 to stably reach the current required ionization voltage; when the control device sends the set required ionization voltage command to the pulse electrostatic eliminator 2, the timing module immediately starts timing; the pulse electrostatic eliminator 2 provides real-time feedback of its own output voltage, and when the output voltage sampled multiple times falls within the allowable error range of the target ionization voltage (e.g., ±0.1kV), it is determined that "the current required ionization voltage has been stably reached", at which point the timing module stops timing and records the duration;

[0138] The control device includes: a combined analysis module, the combined analysis module comprising:

[0139] Displacement curve unit: used to obtain the curve of rise time of the screen leaving the displacement segment and the detection value of the distance detection device during the current rise of the scraper device 1, based on the detection results of the distance detection device;

[0140] The slope calculation unit is used to calculate the overall average slope of the curve within the entire screen printing plate departure displacement segment.

[0141] Speed ​​determination unit: used to determine the instantaneous speed of the scraper leaving the net based on the rise time-distance detection curve of the device;

[0142] Early warning unit: Used to issue an early warning when the speed of the squeegee leaving the screen does not meet the preset squeegee leaving speed range; before screen printing production, based on the current product process requirements, screen characteristics, ink properties and substrate material and other core parameters, the allowable lifting speed range of the squeegee at the critical moment of leaving the screen is pre-calibrated and stored, such as [A, B], and the preset squeegee leaving speed range is [A+C, BC]); C is 0.02~0.05mm / s (taking the typical value of equipment response delay, adapted to the accuracy of mainstream printing machines); used to issue an early warning when the speed is close to the boundary but has not exceeded the limit.

[0143] The calibration process for the preset off-grid instantaneous speed range [A,B] is as follows: Select several groups of similar products for trial printing and collect stable off-grid speed data; determine the basic range [A0,B0] through linear fitting / process mapping table; dynamically correct according to batch production data, with the range fluctuation range ≤±5%.

[0144] If the instantaneous speed at the moment of screen removal exceeds the upper limit of the preset range: This indicates that the initial lift is too fast, which can easily cause the screen to rebound. In the next print run, the upper limit of the lifting acceleration / speed of the subsequent screen removal segments should be reduced to smooth the lifting rhythm and avoid pattern stretching. If the instantaneous speed at the moment of screen removal is below the lower limit of the preset range: This indicates that the initial lift is too slow, which can easily lead to ink sticking. In the next print run, the lifting speed of the subsequent screen removal segments should be increased to compensate for the initial separation lag and ensure overall screen removal smoothness.

[0145] If the screen removal speed is too fast, shorten the displacement segment length in the previous step (reduce the ionization start height by 0.2-0.3 mm; based on trial printing verification, this value range can eliminate the risk of ink backflow from the screen and is compatible with the characteristics of mainstream substrates / inks)) to enter the ionization stage earlier and reduce the risks caused by high-speed lifting. If the screen removal speed is too slow, appropriately extend the displacement segment length in the previous step (increase the ionization start height by 0.2-0.3 mm) to ensure that the screen and substrate are fully separated before initiating electrostatic elimination.

[0146] Trigger timing determination unit: The trigger timing is determined based on the timing module, velocity determination unit, and displacement curve unit;

[0147] Regarding distance detection devices: Sensor selection: Use non-contact displacement sensors (such as laser displacement sensors, ultrasonic sensors, etc.) to avoid damage or interference caused by contact with the screen / scraper. Fix the sensor in a specific position on the scraper device (such as the side of the scraper holder).

[0148] The specific position of the squeegee device refers to a pre-selected, unobstructed, and rigidly stable fixed measurement reference point on the squeegee holder (or squeegee clamp). This position avoids easily worn squeegee blades and other components, ensuring that there is no mechanical obstruction between the squeegee and the end area of ​​the screen printing plate (i.e., the end of the printing stroke, when the squeegee is about to be lifted and detached from the core area of ​​the screen). This allows the optical path, sound field, or electric field of the distance detection device to reach the upper surface of the screen vertically, thereby accurately and continuously measuring the vertical height of the squeegee during the off-screen stage. This provides reliable data for controlling the off-screen lifting speed and avoids pattern pulling or ink layer shifting.

[0149] The screen separation displacement segment refers to the range of displacement during the squeegee's ascent away from the screen printing stencil, from the moment the squeegee blade just leaves the upper surface of the stencil until the vertical distance between the squeegee and the stencil exceeds the preset ionization initiation height (i.e., the minimum safe height for maintaining stable ionization of the electrostatic eliminator). This displacement is crucial for the squeegee to complete physical separation and enter the effective ionization height range, ensuring both sufficient separation of the screen printing stencil from the LCD substrate and that subsequent electrostatic elimination work is carried out at a safe and effective height.

[0150] Based on the real-time detection results of the distance detection device, the displacement curve unit accurately locks the screen leaving the displacement segment during the scraper's ascent, extracts only the "rise time - distance detection value" data within this interval, and generates the corresponding curve (rise time is the horizontal axis and distance detection value is the vertical axis).

[0151] Triggering Time Unit: The time reference zero point is defined as the first sampling time when the distance value changes abruptly from non-zero to zero; if the distance values ​​of three consecutive sampling points are all zero, the first zero-value sampling point is taken as the reference zero point; based on the time reference zero point, the distance detection value and corresponding time data are collected during the upward movement of the scraper device 1 and within the displacement segment of the screen leaving the screen, generating an upward time-distance detection value curve starting from the time reference zero point; on this curve, the curve time point (t1) corresponding to the distance detection value being equal to the preset ionization start height (or corrected after warning) is directly found, and this time point is the target time when the scraper rises from the reference zero point to the ionization start height;

[0152] The response time (T) of the pulse electrostatic eliminator 2 from the issuance of the command to the stable attainment of the required ionization voltage is determined by the timing module.

[0153] The calculation of the ionization start time = target time (t1) - response time (T) is used. The control device generates an ionization start command at the calculated time to ensure that when the scraper rises to the ionization start height, the pulse electrostatic eliminator 2 has stably output the required ionization voltage, thus achieving precise timing matching between the off-grid height and the electrostatic elimination effect.

[0154] Extract the initial rising segment after the zero point of the time reference. This segment can be determined based on 3 to 5 consecutive valid sampling points (corresponding to a time window ≤ 50ms) after the zero point of the time reference. Calculate the slope of the time and distance data within this segment. The resulting slope is the instantaneous speed of the scraper leaving the screen. This slope is used to characterize the rising and falling speed at the critical moment when the scraper and the screen are about to separate, providing a basis for evaluating the smoothness of leaving the screen and optimizing the rising and falling speed.

[0155] The beneficial effects of the above technical solution are as follows:

[0156] This invention achieves proactive and precise control through innovative time reference zero point, precise curve application, independent quantification of off-grid instantaneous speed, and closed-loop control.

[0157] This invention directly finds the time point on the rise time-distance detection curve where the distance equals the preset ionization start height, and uses it as the target time when the scraper reaches the effective ionization height, without relying on speed estimation, delay model or mechanical compensation.

[0158] This invention extracts the zero point of the time reference and the next 3-5 valid sampling points from the curve, and calculates the speed of the squeegee at the moment of separation from the screen by the slope. For the first time, it uses the "initial rising and falling speed at the critical moment of separation" as an independent quantifiable indicator. This indicator accurately reflects the dynamic characteristics of the squeegee as it is about to separate from the screen printing plate.

[0159] This invention uses the instantaneous speed at the moment of screen departure as an active correction variable, rather than a simple detection indicator: when the speed exceeds the upper limit, it automatically reduces the acceleration of subsequent screen departure segments, smooths the lifting rhythm, and suppresses screen rebound; when the speed exceeds the lower limit, it automatically increases the acceleration of subsequent screen departure segments to compensate for the initial separation lag and ensure complete ink separation; at the same time, it can dynamically adjust the length of the screen departure displacement segment to adapt to the separation requirements at different speeds.

[0160] This invention relies on the rise time-distance detection curve to complete timing calculations, velocity detection, and control correction, eliminating the need for additional electrostatic response compensation, multi-module linkage, or complex algorithm modeling. It achieves a creative simplification of "providing full-process control information with a single curve." While ensuring accuracy, it significantly reduces system complexity and failure risk.

[0161] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An LCD screen printing apparatus with electrostatic elimination function, comprising an LCD printing apparatus body (1), the LCD printing apparatus body (1) including a squeegee device (11), characterized in that: The LCD screen printing apparatus also includes: Installation device (3): includes several connecting frames (31), the connecting frame (31) includes a vertical plate (311) and a mounting plate (312) connected to the lower end of the vertical plate (311). The vertical plate (311) is provided with a vertical strip hole (3111). The scraper device (11) is provided with a threaded hole corresponding to the vertical strip hole (3111). The non-nut section of the screw (313) passes through the vertical strip hole (3111) and is connected to the corresponding threaded hole. The mounting plate (312) is provided with a non-vertical strip hole (3121). The non-nut section of the screw (314) passes through the non-vertical strip hole (3121) and is connected to the outer shell (21) of the pulse static electricity eliminator (2). The control device is electrically connected to the LCD printing device body (1) and the pulse static elimination rod (2); Storage device: Stores a reference mapping model, which is the ideal ionization parameter range corresponding to each commonly used squeegee printing speed range under the corresponding theoretical printing pressure conditions of the reference LCD substrate; Speed ​​detection device: used to detect the printing speed of the squeegee; Electrostatic discharge (ESD) detection device: used to detect the surface electrostatic voltage of the LCD substrate after ionization following screen printing testing; Displacement detection device: used to detect the distance the doctor blade moves along the printing direction; The control device includes a test control module, which comprises: Process parameter acquisition unit: acquires the theoretical printing pressure range and the theoretical squeegee printing speed under non-static elimination state of the substrate under test; Measurement and control unit 1: Select multiple test speeds within the theoretical squeegee printing speed range, and control the left and right translation device to start and stably run to each test speed. Based on the displacement data of the squeegee along the printing direction detected by the displacement detection device, determine the stable displacement corresponding to each test speed. Analysis Unit 1: Used to determine several matching ideal ionization parameter ranges from the reference mapping model based on the theoretical squeegee printing speed of the substrate under test; and to generate several test parameter sets based on the median of the theoretical printing pressure range, the median of the theoretical squeegee printing speed, and the median of each matching ideal ionization parameter range of the substrate under test. Measurement and control unit 2: Used to control the silkscreen printing test of the test substrate based on each test parameter group; Analysis Unit Two: Used to determine the current target ionization parameters based on the detection results of the screen printing test control process based on Measurement and Control Unit Two and the stable displacement corresponding to each test speed.

2. The LCD screen printing apparatus with electrostatic elimination function according to claim 1, characterized in that: The LCD printing device body (1) also includes: A printing table (12) is provided, with a printing platform (121) at the top and a workpiece placement seat (13) on the printing platform (121). Lifting device one (14) is installed on the upper platform of the printing table (12) and is located behind the workpiece placement seat (13). The lifting end of the lifting device one (14) is connected to the connecting seat (19). The connecting seat (19) is connected to the left and right translation device (16). The moving end of the left and right translation device (16) is connected to the lifting device two (15). The lifting end of the lifting device two (15) is connected to the scraper device (11). The scraper device (11) includes lifting device three (112). The lifting device three (112) is connected to the lifting end of the lifting device two (15). The lifting end of the lifting device three (112) is connected to the scraper (111). A connecting frame (18) is connected to a connecting seat (19), and a scraper (111) is located inside the connecting frame (18); A screen printing stencil (17) is connected to the inside of a connecting frame (18).

3. The LCD screen printing apparatus with electrostatic elimination function according to claim 1, characterized in that: The length direction of the non-vertical strip hole (3121) is the left-right direction.

4. The LCD screen printing apparatus with electrostatic elimination function according to claim 1, characterized in that: The connecting frame (31) is connected to the forward direction side of the doctor blade device (11) along the printing motion direction.

5. An LCD screen printing apparatus with electrostatic elimination function according to claim 1, characterized in that: The distance between the installation position of the pulse static eliminator (2) and the doctor blade (111) along the printing movement direction is 5-15cm.

6. An LCD screen printing apparatus with electrostatic elimination function according to claim 1, characterized in that: The control device is connected to the storage device, speed detection device, electrostatic detection device, and displacement detection device via signals, respectively.

7. An LCD screen printing apparatus with electrostatic elimination function according to claim 1, characterized in that: The defined unit includes: Analysis Sub-unit 1: Based on the detection results of the screen printing test control process of measurement and control unit 2, construct a matrix of "test squeegee printing speed - ionization parameter - ionization detection device detection value" and mark the stable displacement corresponding to the test squeegee printing speed. Analysis Subunit 2: Used to determine the current target ionization parameters based on the matrix; When the substrate to be tested is officially printed in batches, the control device controls the pulse electrostatic eliminator (2) to work based on the current target ionization parameters.

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