A knotless screen with both equally spaced and non-equally spaced grid lines and its manufacturing process

Abstract

The present invention relates to the field of solar cell screen printing technology, and discloses a knotless screen with both equally spaced and unequally spaced grid lines and a manufacturing process. The screen includes: an equally spaced region composed of a plurality of straight grid lines with fixed spacing; an unequally spaced region composed of a plurality of curved grid lines with gradually varying spacing; a transition region located between the equally spaced and unequally spaced regions, in which the grid line spacing gradually transitions from equally spaced to unequally spaced. The screen is composed of a composite of nickel alloy mesh and polymer film, achieved through a hot pressing process; straight grid line slots are formed in the equally spaced region using photolithography and etching techniques; and curved grid line slots are generated in the unequally spaced region using scanning line selection technology. The present invention achieves diverse grid line distribution, enhanced screen strength, and significantly improved printing quality through optimized grid line region design, a combination of photolithography and scanning line selection processes, and enhanced structural optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell screen printing, in particular to a knotless screen plate with coexistence of equidistant and unequally spaced grid lines and a manufacturing process thereof. Background Art

[0002] Knotless screens are a precision tool widely used in screen printing for solar cells. By removing the traditional knots from the warp and weft weave, they create a more transparent grid pattern. Knotless screens are typically manufactured using photolithography, etching, or wire drawing techniques to create highly precise grid slots, enhancing ink permeability and pattern accuracy during screen printing. They are an essential core technology in photovoltaic cell manufacturing.

[0003] Existing knotless screen production processes mostly use a single processing method. For example, the photolithography etching process mainly uses photosensitive materials and chemical etching technology to form regular, evenly spaced straight grid lines. Its characteristics are precise grid line size and excellent light transmittance; the wire drawing process forms a non-evenly spaced grid line pattern by physically removing local warp and weft lines of the mesh, which is suitable for complex grid line design.

[0004] However, the application of existing knotless screen manufacturing processes still has limitations. On the one hand, the equally spaced straight grid lines cannot meet the diverse grid line design requirements, limiting the adaptability of the screen. On the other hand, the single process mode leads to insufficient mechanical strength of the screen, making it difficult to balance the processing accuracy and durability of complex patterns. In addition, the lack of transition design results in uneven connection between different areas of the screen, leading to problems such as false printing, screen blockage and stress concentration during the printing process. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a knotless screen and a manufacturing process in which both equally spaced and unequally spaced grid lines can coexist, solving the problem that the existing knotless screen cannot take into account the coexistence of equally spaced and straight grid lines and unequally spaced and curved grid lines.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a knotless screen with both equally spaced and unequally spaced grid lines and a manufacturing process, the screen comprising:

[0007] The equally spaced area consists of multiple straight grid lines with fixed spacing;

[0008] The non-uniformly spaced area consists of multiple curved lines with gradually changing spacing;

[0009] A transition region is located between the equal-spaced region and the non-equal-spaced region, and the grid line spacing gradually transitions from equal spacing to non-equal spacing;

[0010] The screen is made of nickel alloy mesh and polymer film, and the composite is achieved through a hot pressing process;

[0011] Forming straight gate line slots in the equally spaced areas by photolithography and etching techniques;

[0012] In the non-uniformly spaced regions, curved gate line slots are generated by scanning and line selection technology.

[0013] Preferably, the width of the gate lines in the equally spaced area is 10-15 μm, the gate line spacing is 30-50 μm, and the depth of the gate line slots is 3-5 μm.

[0014] Preferably, the gate line width in the non-uniformly spaced region is 8-12 μm, the gate line spacing varies in the range of 30-100 μm, and the variation of the spacing is distributed according to an exponential or linear rule.

[0015] Preferably, the gate line spacing variation step in the transition region is 5 μm, and the gate line transition radius is 100-200 μm.

[0016] The present invention also provides a process for producing a knotless screen with both equally spaced and unequally spaced grid lines, which is characterized by comprising the following steps:

[0017] Area division: Use design software to divide the screen into equal-spaced areas, non-equal-spaced areas and transition areas;

[0018] Material composite: nickel alloy mesh and polymer film are composited through hot pressing process to form the screen substrate;

[0019] Equally spaced area processing: forming straight gate line slots in the equally spaced areas by photolithography and etching techniques;

[0020] Non-uniformly spaced area processing: generating curved gate line slots in the non-uniformly spaced area by scanning line selection technology;

[0021] Processing of transition area: combining photolithography and scanning technology to process gradient grid line slots in the transition area;

[0022] Strength optimization: local thickening treatment is performed around the grid line slots of the screen, and cross support structures are added in non-uniformly spaced areas;

[0023] Quality inspection: The width, spacing and shape of the gate line slots are inspected using a scanning electron microscope.

[0024] Preferably, the material composite comprises:

[0025] The nickel alloy mesh and the polymer film are stacked and placed in a hot pressing device;

[0026] The composite substrate was formed by pressing at a temperature of 180° C. and a pressure of 5 MPa for 10 minutes.

[0027] Preferably, the equidistant area processing includes:

[0028] Coating a positive photoresist with a thickness of 3 μm on the equally spaced areas;

[0029] The gate line pattern is produced by laser direct writing technology with an exposure resolution of 1μm;

[0030] The area coated with the photolithography pattern was immersed in a 10 wt % NaOH solution and etched for 15 minutes to form a gate line trench with a depth of 3 to 5 μm.

[0031] Preferably, the non-equidistant area processing includes:

[0032] The scanning line selection device is used to locate the grid lines according to the preset non-uniform spacing pattern, and the scanning path is optimized based on the arc fitting algorithm;

[0033] Adjusting the tension during scanning to form curved grating lines that conform to non-uniformly spaced patterns;

[0034] The generated grid line position error is corrected and the error range is controlled within 90 to 110 μm.

[0035] Preferably, the transition region processing includes:

[0036] The straight grid line part at the starting point of the gradient is processed by photolithography and etching technology;

[0037] The curved grid line part at the end point of the gradient is processed using scanning line selection technology;

[0038] The grid line spacing in the transition area is adjusted to a change step of 5 μm, and the transition radius is 150 to 200 μm.

[0039] Preferably, the strength optimization includes:

[0040] Spray a 2μm thick reinforcing colloid around the grid line slots in the equally spaced area to increase the compressive resistance;

[0041] Cross support lines are added in the non-uniformly spaced areas, with a width of 5 μm and a spacing of 50 μm, to disperse the stress of the curved gate lines.

[0042] The present invention provides a knotless screen and a manufacturing process for coexisting equidistant and unequally spaced grid lines. It has the following beneficial effects:

[0043] 1. The present invention achieves diversified grid line distribution and high structural stability by designing a knotless screen structure with equally spaced straight grid lines and unequally spaced curved grid lines, combined with gradual optimization of the transition area, thereby improving the accuracy and adaptability of screen printing while ensuring good light transmittance and mechanical strength.

[0044] 2. The present invention optimizes the compressive resistance of equidistant areas and the stress dispersion performance of non-equidistant areas by adopting a composite substrate and dynamic processing technology, thereby enhancing the durability of the screen in high-intensity screen printing applications and ensuring the processing consistency and long-term stability of complex grid line patterns.

[0045] 3. The present invention combines photolithography with scanning line selection technology to accurately control the width, spacing and depth of the grid line slots. At the same time, by strengthening the colloid and optimizing the process of the cross-support structure, it solves the risks of false printing, grid blockage and deformation of the fine grid line slots, and improves the functional reliability and economic benefits of the overall screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart for preparing the knotless screen of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the specification of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] Please see the attached Figure 1 The embodiment of the present invention provides a knotless screen with both equally spaced and non-equally spaced grid lines, the screen comprising:

[0049] The equally spaced area is composed of multiple straight grid lines with fixed spacing. The straight grid line design in this equally spaced area ensures the consistency of the current conduction path, improves the accuracy of screen printing and cell efficiency, and its light transmittance optimizes the photoelectric conversion efficiency of the solar cell;

[0050] The non-uniformly spaced region is composed of multiple curved grid lines with gradually varying spacing. The non-uniformly spaced region provides a highly flexible grid line spacing distribution, adapting to the needs of different photovoltaic cell designs while reducing the impact of the secondary grid lines on light absorption, thereby optimizing the overall photovoltaic performance of the cell.

[0051] The transition area is located between the equal-spaced area and the non-equal-spaced area. The grid line spacing gradually changes from equal spacing to non-equal spacing. The gradual change design of the transition area solves the connection problem between the equal-spaced and straight grid lines and the non-equal-spaced curved grid lines, ensuring the stability of the overall structure of the screen and improving the consistency of the printing effect.

[0052] The screen is made of a composite of nickel alloy mesh and polymer film, which is achieved through a hot pressing process. The composite process combines the high strength of the nickel alloy mesh with the flexibility of the polymer film to form a screen structure that is both rigid and flexible, effectively improving the screen's service life and processing adaptability.

[0053] Photolithography and etching techniques are used to form straight grid line slots in evenly spaced areas. High-precision straight grid line slot processing is achieved through photolithography and etching techniques in evenly spaced areas, ensuring uniform ink permeability during the screen printing process and improving the conductivity of the main grid lines.

[0054] In non-uniformly spaced areas, curved grid line slots are generated through scanning line selection technology. The flexible processing of curved grid lines is achieved by using scanning line selection technology in non-uniformly spaced areas, providing a customized secondary grid line design solution for solar cells and improving the overall performance of the cells.

[0055] Please see the attached Figure 1 In a preferred embodiment of the present invention, the width of the grid lines in the equally spaced areas is 10 to 15 μm, the grid line spacing is 30 to 50 μm, and the depth of the grid line slots is 3 to 5 μm. The grid line width of 10 to 15 μm minimizes the shielding of light by the grid lines while ensuring high conductivity, thereby improving the photoelectric conversion efficiency in solar cells. The design of the grid line spacing effectively reduces the loss of lateral current transmission while improving the light transmittance, providing basic support for high-efficiency solar cells. The double etching process achieves precise control of the depth of the grid line slots, ensuring the consistency of ink filling and the mechanical stability of the screen, effectively improving the quality and efficiency of screen printing.

[0056] Please see the attached Figure 1 In a preferred embodiment of the present invention, the width of the grid lines in the non-uniformly spaced areas is 8 to 12 μm, the grid line spacing varies in the range of 30 to 100 μm, and the spacing variation is distributed according to an exponential or linear law. The optimization of the width range minimizes the light blocking by the secondary grid lines while maintaining the necessary conductivity, providing a reliable foundation for the optical and electrical performance of solar cells. Through reasonable spacing variation design, the non-uniformly spaced areas achieve a balance between light transmittance and mechanical properties, meeting the diverse needs of the secondary grid lines.

[0057] Please see the attached Figure 1In a preferred embodiment of the present invention, the grid line spacing change step size in the transition area is 5μm, and the grid line transition radius is 100-200μm. Through the design of a fixed step size of 5μm and high-precision scanning processing, the grid line spacing in the transition area changes smoothly and evenly, avoiding structural mutations and uneven printing problems, and improving the mechanical and printing performance of the entire screen. Through the reasonable design and fitting processing of the transition radius, the transition area achieves smooth connection, avoiding grid line breakage or stress concentration problems caused by excessive transition angles, and extending the service life of the screen.

[0058] Please see the attached Figure 1 The present invention also provides a process for producing a knotless screen with both equally spaced and non-equally spaced grid lines, comprising the following steps:

[0059] Region division: The design software divides the screen into equal-pitch areas, non-equal-pitch areas, and transition areas. This region division not only ensures the functional coordination of equal-pitch and straight lines with non-equal-pitch and curved lines, but also achieves dual optimization of mechanical strength and optical performance through simulation verification.

[0060] Material composite: nickel alloy mesh and polymer film are composited through hot pressing process to form the screen substrate. The material composite process makes the screen both high-strength and flexible, ensuring its stability during processing and use, and providing excellent substrate support for subsequent fine processing;

[0061] Equally spaced area processing: Straight grid line slots are formed in equally spaced areas through photolithography and etching technology. By processing the equally spaced areas through photolithography and etching technology, grid line slots with high straightness and uniform spacing are formed, which improves the conductivity and printing accuracy of the main grid line;

[0062] Non-uniformly spaced area processing: Scanning line selection technology is used to generate curved grid line slots in non-uniformly spaced areas. This technology enables precise processing of curved grid lines in non-uniformly spaced areas, meeting the diverse design requirements of secondary grid lines and significantly improving the optical performance of the screen.

[0063] Transition area processing: Combining photolithography and scanning technology to process gradient grid line slots in the transition area, the transition area processing realizes smooth connection between equal-spaced and non-equal-spaced grid lines through gradient design and optimized path, thus improving the mechanical stability of the screen and printing quality;

[0064] Strength Optimization: The screen is locally thickened around the grid slots and cross-support structures are added in unevenly spaced areas. The local thickening and cross-support design significantly improves the overall strength of the screen, extends its service life, and maintains stable performance in high-intensity printing environments.

[0065] Quality inspection: The width, spacing and shape of the grid line slots are inspected using a scanning electron microscope. This quality inspection ensures that the screen processing accuracy and performance meet the requirements of efficient solar cell printing.

[0066] Please see the attached Figure 1 In a preferred embodiment of the present invention, the material composite comprises:

[0067] The nickel alloy mesh and polymer film are stacked and placed in a hot pressing device. The nickel alloy mesh serves as the core of the substrate, providing high strength, corrosion resistance, and excellent processing performance, while the polymer film serves as an auxiliary material, providing flexible support and cushioning. Through the rational combination of the nickel alloy mesh and the polymer film, the substrate possesses both rigidity and flexibility, providing an excellent material foundation for subsequent hot pressing.

[0068] The composite substrate is formed by pressing at a temperature of 180°C and a pressure of 5MPa for 10 minutes. The hot pressing treatment achieves a strong bond between the nickel alloy mesh and the polymer film through high temperature and high pressure. The composite substrate has high mechanical strength, flexible cushioning and good structural stability.

[0069] Please see the attached Figure 1 In a preferred embodiment of the present invention, the equally spaced area processing includes:

[0070] A 3μm thick positive photoresist is applied to evenly spaced areas. The evenly coated photoresist provides a high-quality photosensitive film layer for gate line pattern processing, ensuring the accuracy of the photolithographic pattern and the uniformity of the slot processing.

[0071] The gate line pattern is produced by laser direct writing technology with an exposure resolution of 1μm. Laser direct writing technology accurately forms the gate line pattern in equidistant areas through high-resolution exposure and development processes, ensuring the flatness and dimensional accuracy of the gate line, providing a precise template for the subsequent etching step;

[0072] The area coated with the photolithography pattern is immersed in a 10wt% NaOH solution and etched for 15 minutes to form a grid line slot with a depth of 3 to 5μm. By adjusting the concentration, temperature and time of the etching solution, a grid line slot with uniform depth and smooth edges is formed, meeting the requirements of high-precision screen printing.

[0073] Please see the attached Figure 1 In a preferred embodiment of the present invention, the non-equidistant area processing includes:

[0074] The scanning line selection device is used to locate the grid lines according to the preset non-uniformly spaced pattern. The scanning path is optimized based on the arc fitting algorithm. Through the combination of the arc fitting algorithm and the high-precision scanning device, the grid line positioning can meet the design requirements of complex patterns in non-uniformly spaced areas, while reducing path deviation and providing a high-precision path reference for subsequent processing;

[0075] Adjust the tension during the scanning process to form curved grating lines that conform to the non-uniformly spaced pattern. Through dynamic tension adjustment, the curved grating lines are precisely formed during the generation process, while avoiding grating line breakage and morphological deviation caused by stress concentration, thereby improving the processing quality of non-uniformly spaced areas.

[0076] The generated grid line position error is corrected, and the error range is controlled within 90 to 110 μm. Through the joint correction of optical detection and path optimization, the grid line processing error in non-uniformly spaced areas is significantly reduced, and the actual position deviation is always controlled within the range of 90 to 110 μm, meeting the requirements of high-precision screen printing.

[0077] Please see the attached Figure 1 In a preferred embodiment of the present invention, the transition region processing includes:

[0078] The straight grid lines at the starting point of the gradient are processed using photolithography and etching technology. In the processing of the straight grid lines at the starting point of the gradient, photolithography and etching technology form slots with precise dimensions and uniform spacing, providing a stable starting point support for the smooth change of the transition area.

[0079] The curved grating at the end of the gradient is processed using scanning line selection technology. This technology forms non-uniformly spaced slots with precise curvature, providing high-precision support for the functional requirements of the non-uniformly spaced area.

[0080] The grid line spacing change step size in the transition area is adjusted to 5μm, and the transition radius is 150-200μm. By adjusting the spacing change step size and transition radius, the gradient area achieves a smooth transition between equally spaced and straight grid lines and non-equally spaced and curved grid lines, significantly improving the stability of the overall structure of the screen.

[0081] Please see the attached Figure 1 In a preferred embodiment of the present invention, the strength optimization includes:

[0082] A 2μm thick reinforcing colloid is sprayed around the grid line slots in the evenly spaced area to increase the pressure resistance. The uniform spraying of the reinforcing colloid significantly enhances the pressure resistance around the grid line slots, avoiding the problem of slot deformation or damage caused by excessive pressure during the screen printing process, and extending the service life of the screen.

[0083] Cross support lines are added in non-uniformly spaced areas with a width of 5μm and a spacing of 50μm to disperse the stress of the curved grid lines. The addition of cross support lines effectively disperses the stress concentration in the non-uniformly spaced areas, prevents deformation or breakage of the grid line slots due to excessive local stress, and improves the overall mechanical stability of the screen. After enhanced colloid spraying and the addition of cross support lines, the strength and durability of the screen are significantly improved, especially in high-intensity screen printing applications, showing excellent performance stability.

[0084] In order to better understand the present invention, the above contents are described in detail below in conjunction with specific embodiments.

[0085] Example 1: Screen Design without Adding Transition Area

[0086] Area division: The screen only includes equally spaced areas and non-equally spaced areas, without transition areas.

[0087] Processing technology:

[0088] The straight grid line slots are processed in the equally spaced areas by photolithography and etching technology;

[0089] The non-uniformly spaced areas directly use the scanning line selection technology to generate curved grid lines without setting a gradual transition part;

[0090] The two areas are directly connected without any gradient design.

[0091] Effects and problems:

[0092] Simple structure and high processing efficiency;

[0093] There is a significant variation in spacing between evenly spaced and straight lines and unevenly spaced curved lines, which leads to increased problems of void printing and screen blocking during the printing process.

[0094] Example 2: Adding a transition region without optimizing strength

[0095] Region division: Add transition area, which realizes the gradual transition from equidistant and straight grid lines to non-equidistant curved grid lines.

[0096] Processing technology:

[0097] Equally spaced and straight grid lines are processed using photolithography and etching technology;

[0098] Non-uniformly spaced and curved lines are processed using scanning line selection technology;

[0099] The transition area achieves a gradient grid line spacing (step length 5μm) and transition radius (150-200μm) by combining photolithography and scanning technology.

[0100] Effects and problems:

[0101] The transition area achieves smooth connection, significantly reducing the risk of false printing and screen blocking, and improving printing quality;

[0102] Failure to optimize the overall mechanical strength of the screen may result in local deformation and breakage of the screen during high-frequency printing.

[0103] Example 3: Adding a transition zone and optimizing strength (Solution of the present invention)

[0104] Zone division: Set up gradient transition areas between equally spaced areas and non-equally spaced areas, while optimizing the overall strength of the screen.

[0105] Processing technology:

[0106] Equally spaced areas: Photolithography and etching techniques are used to form high-precision straight grid lines;

[0107] Non-uniformly spaced areas: Use scanning line selection technology to generate curved lines, and the path is optimized based on arc fitting;

[0108] Transition area: Combine photolithography and scanning technology to achieve gradual transition;

[0109] Strength optimization: A reinforcing colloid layer is sprayed around the slots in the evenly spaced areas, and cross support lines are added in the unevenly spaced areas to disperse stress and improve compressive strength.

[0110] Effects and advantages:

[0111] Achieves smooth transition between evenly spaced and straight lines and unevenly spaced curved lines, improving printing quality.

[0112] Strengthened colloid and cross support lines optimize the overall mechanical strength of the screen and extend its service life;

[0113] Maintains high adaptability and processing consistency under complex grid line design requirements.

[0114] Comparative experiment 1: Printing uniformity experiment

[0115] Experimental purpose: To verify the advantages of the knotless screen designed by the present invention in terms of ink printing uniformity with both equally spaced and non-equally spaced grid lines.

[0116] Experimental setup

[0117] Sample setup

[0118] Control group 1: Traditional equally spaced screen with no transition areas, processed using photolithography only.

[0119] Control group 2: non-uniformly spaced screens, processed using only scanning line selection technology, with no transition area design.

[0120] Control 3: Screen with transition areas but no intensity optimization.

[0121] Experimental group: The present invention includes equal spacing, transition area and non-equal spacing grid line designs, and completes strength optimization.

[0122] Test parameters

[0123] Ink type: conductive silver paste ink;

[0124] Printing equipment: high-precision screen printing machine;

[0125] Test area: 100mm×100mm;

[0126] Test conditions: Each group is tested after 10 printings.

[0127] Evaluation indicators

[0128] Uniformity Index: Statistical analysis of ink coverage in each area through microscopic imaging.

[0129] Void printing ratio: Calculate the percentage of void printing (area where ink is not fully penetrated) in the total area.

[0130] Accumulation rate: The percentage of accumulation area (excess ink area) to the total area.

[0131] Experimental procedures

[0132] Screen preparation: Install screens according to groups and adjust screen printing equipment to ensure consistent printing conditions.

[0133] Ink printing: Conductive silver paste ink was used and printed 10 times on the test substrate.

[0134] Microscopic inspection: After each printing, use a microscope to photograph the ink distribution in the area and record the areas of void printing and accumulation.

[0135] Data statistics: Calculate the uniformity index, false printing ratio and accumulation rate through image analysis software, and organize the data.

[0136] The comparative experimental data are shown in Table 1:

[0137] Table 1 Ink uniformity data of different screen groups

[0138] Group Uniformity index (%) False printing ratio (%) Accumulation rate (%) Control group 1 78 12 15 Control group 2 84 10 12 Control group 3 89 6 10 Experimental group (present invention) 95 2 5

[0139] From the data in Table 1, we can get:

[0140] Control group 1 (traditional screen): The uniformity index was the lowest, at only 78%, and the percentage of false prints (12%) and the accumulation rate (15%) were high. This indicates that the traditional screen cannot adapt to complex grid line designs, resulting in uneven ink distribution.

[0141] Control group 2 (non-uniformly spaced screen): The uniformity index increased to 84%, but the lack of transition area design resulted in some virtual printing at the junction of non-uniformly spaced and straight lines (the virtual printing ratio was 10%).

[0142] Control group 3 (with transition zones but no strength optimization): The uniformity index further improved to 89%, and the smooth transition zones reduced void printing (6%). However, the pile-up rate (10%) increased after high-frequency printing, indicating that insufficient structural strength led to reduced printing stability.

[0143] Experimental group (inventive method): Uniformity index reached 95%, the percentage of false prints dropped to 2%, and the accumulation rate was only 5%. Through transition zone design and structural strength optimization, the experimental group achieved excellent ink distribution uniformity under complex grid line design and maintained stability at high-frequency printing.

[0144] Comparative experiment 2: mechanical strength test

[0145] Experimental purpose: To verify the mechanical performance advantages of the screen of the present invention in high-strength screen printing.

[0146] Experimental setup

[0147] Sample setup

[0148] Control group 1: Traditional screen, only grid line slots processed, no strength optimization (no spraying of strengthening colloid, no addition of cross support wires).

[0149] Control group 2: The reinforced colloid was sprayed in the evenly spaced areas, but there was no support design in the non-evenly spaced areas.

[0150] Control group 3: Cross support lines were added in the non-equally spaced areas, but no reinforcing colloid was added in the equally spaced areas.

[0151] Experimental group: The present invention sprays the reinforcing colloid in the equally spaced areas and adds cross support lines in the non-equally spaced areas.

[0152] Test parameters

[0153] Compression test: Gradually apply pressure and measure the compressive strength (unit: MPa) at the point where the screen breaks.

[0154] Lifespan test: simulates screen printing and tests the screen for deformation and damage after 1,000 printing cycles.

[0155] Evaluation indicators

[0156] Compressive strength: maximum pressure resistance value, unit is MPa;

[0157] Service life: The integrity rate of the screen after 1000 printing cycles (the proportion without obvious deformation or damage, unit is %).

[0158] Experimental procedures

[0159] Sample preparation

[0160] Install different groups of screen samples, ensure they are securely installed, and adjust the test equipment parameters to be consistent.

[0161] Stress resistance test

[0162] Place the screen on the press and gradually increase the pressure;

[0163] Record the maximum pressure value when the screen slot area is deformed or damaged.

[0164] Service life test

[0165] Using screen printing equipment, each set of screens was printed 1000 times under the same conditions;

[0166] Check the integrity of the screen after printing (including slot deformation, support wire breakage, etc.).

[0167] Statistics

[0168] Collect compressive strength and intactness data, and organize and compare the results.

[0169] The comparative experimental data are shown in Table 2:

[0170] Table 2 Mechanical strength test data of different screen groups

[0171] Group Compressive strength (MPa) Service life intact rate (%) Control group 1 1.2 55 Control group 2 1.8 70 Control group 3 2 80 Experimental group (present invention) 2.8 95

[0172] From the data in Table 2, we can get:

[0173] Control group 1 (traditional screen): The compressive strength was the lowest, at only 1.2 MPa. The slot area was prone to deformation during high-frequency printing, and the service life intact rate was only 55%, demonstrating poor mechanical properties.

[0174] Control group 2 (reinforced colloid spraying in equal-spaced areas): compressive strength increased to 1.8 MPa. The equal-spaced areas had good compressive performance, but the non-equal-spaced areas still showed local deformation due to the lack of support structure. The service life intact rate was 70%;

[0175] Control group 3 (support lines added to non-uniformly spaced areas): The compressive strength increased to 2.0 MPa. The support structure in the non-uniformly spaced areas effectively dispersed the stress. However, the slot deformation problem still existed in the uniformly spaced areas due to the lack of enhanced colloid treatment. The service life intact rate was 80%;

[0176] Experimental group (inventive method): Compressive strength reached 2.8 MPa. Both equally spaced and unevenly spaced areas were reinforced, achieving a synergistic optimization of stress dispersion and slot compression resistance. The service life integrity rate reached 95%, and the screen maintained excellent performance even after 1,000 high-frequency print cycles.

[0177] Comparative experiment 3: Photoelectric performance test

[0178] Experimental purpose: To verify the photoelectric performance improvement effect of the screen printing of solar cells.

[0179] Experimental setup

[0180] Sample setup

[0181] Control group 1: Traditional uniformly spaced screen with straight lines and no non-uniformly spaced areas.

[0182] Control group 2: non-uniformly spaced screen with curved lines but no transition area.

[0183] Control 3: Screen with transition areas but without optimized intensity.

[0184] Experimental group: The present invention has a design of equal spacing, transition areas and non-equal spacing of grid lines, while enhancing structural strength.

[0185] Test parameters

[0186] Light transmittance: measures the light transmittance of the photovoltaic cells covered by the screen under the same lighting conditions (unit: %).

[0187] Photovoltaic conversion efficiency: Tests the current output and power conversion efficiency of photovoltaic cells (unit: %).

[0188] Evaluation indicators

[0189] Light transmittance: the optimization effect of screen design on light transmittance;

[0190] Photoelectric conversion efficiency: The screen grid structure improves the overall energy conversion efficiency of the battery.

[0191] Experimental procedures

[0192] Screen preparation: Set up screen samples according to different groups and install them on the screen printing equipment.

[0193] Photovoltaic cell printing uses photovoltaic cell substrates and conductive silver paste ink of the same specifications, and performs 10 printings to ensure the stability of the samples.

[0194] Light transmittance test

[0195] Under standard lighting conditions, measure the light transmittance of each set of printed photovoltaic cells;

[0196] The data is recorded by optical instruments such as spectrophotometers.

[0197] Photoelectric conversion efficiency test

[0198] Under simulated sunlight conditions, use a test instrument to measure the output current and power of the battery;

[0199] Calculate the photoelectric conversion efficiency of each group of cells.

[0200] The comparative experimental data are shown in Table 3:

[0201] Table 3 Photoelectric performance test data of different screen groups

[0202] Group Light transmittance (%) Photoelectric conversion efficiency (%) Control group 1 78 16.2 Control group 2 85 17.5 Control group 3 88 18.2 Experimental group (present invention) 92 19.5

[0203] From the data in Table 3, we can get:

[0204] Control group 1 (traditional equally spaced screen): The light transmittance was the lowest, at only 78%. Because the grid lines had a large light-shielding area, this limited the solar cell's light absorption capacity. The photoelectric conversion efficiency was 16.2%, indicating poor performance.

[0205] Control group 2 (non-uniformly spaced screen): Light transmittance increased to 85%, and the photoelectric conversion efficiency increased to 17.5% due to the curved grid line design, which reduced the light-shielding area. However, the lack of a transition area resulted in uneven optical and electrical performance at the grid line junctions.

[0206] Control group 3 (with transition zone but no intensity optimization): Light transmittance further increased to 88%. The transition zone design smoothed the grid line distribution and reduced connection issues. The photoelectric conversion efficiency was 18.2%, but the insufficient intensity affected long-term performance.

[0207] Experimental Group (Invention): The light transmittance reached the highest, reaching 92%. The design of equal spacing, uneven spacing, and transition zones achieved optimal light utilization. The photoelectric conversion efficiency increased to 19.5%, achieving not only efficient energy conversion but also long-term stability.

[0208] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A process for producing a knotless screen with both equally spaced and non-equally spaced grid lines, characterized in that: The knotless mesh plate comprises: The equally spaced area consists of multiple straight grid lines with fixed spacing; The non-uniformly spaced area consists of multiple curved lines with gradually changing spacing; A transition region is located between the equal-spaced region and the non-equal-spaced region, and the grid line spacing gradually transitions from equal spacing to non-equal spacing; The knotless mesh plate is made of a composite of nickel alloy mesh and polymer film, and the composite is achieved through a hot pressing process; Forming straight gate line slots in the equally spaced areas by photolithography and etching techniques; Generating curved gate line slots in the non-uniformly spaced area by scanning line selection technology; The manufacturing process comprises the following steps: Area division: The knotless screen is divided into equal-spaced areas, non-equal-spaced areas and transition areas through design software; Material composite: nickel alloy mesh and polymer film are composited through hot pressing process to form the screen substrate; Equally spaced area processing: forming straight gate line slots in the equally spaced areas by photolithography and etching techniques; Non-uniformly spaced area processing: generating curved gate line slots in the non-uniformly spaced area by scanning line selection technology; Processing of transition area: combining photolithography and scanning technology to process gradient grid line slots in the transition area; Strength optimization: performing local thickening treatment around the grid line slots of the knotless mesh and adding cross-support structures in non-uniformly spaced areas; the strength optimization includes: Spray a 2μm thick reinforcing colloid around the grid line slots in the equally spaced area to increase the compressive resistance; Add cross support lines in the non-uniformly spaced areas with a width of 5μm and a spacing of 50μm to disperse the stress of the curved gate lines; Quality inspection: The width, spacing and shape of the gate line slots are inspected using a scanning electron microscope.

2. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The material composite comprises: The nickel alloy mesh and the polymer film are stacked and placed in a hot pressing device; The composite substrate was formed by pressing at a temperature of 180° C. and a pressure of 5 MPa for 10 minutes.

3. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The equidistant area processing includes: Coating a positive photoresist with a thickness of 3 μm on the equally spaced areas; The gate line pattern is produced by laser direct writing technology with an exposure resolution of 1μm; The area coated with the photoresist pattern was immersed in a 10 wt % NaOH solution and etched for 15 minutes to form a gate line trench.

4. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The non-equidistant area processing includes: The scanning line selection device is used to locate the grid lines according to the preset non-uniform spacing pattern, and the scanning path is optimized based on the arc fitting algorithm; Adjusting the tension during scanning to form curved grating lines that conform to non-uniformly spaced patterns; The generated grid line position error is corrected and the error range is controlled within 90 to 110 μm.

5. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The transition area processing includes: The straight grid line part at the starting point of the gradient is processed by photolithography and etching technology; The curved grid line part at the end point of the gradient is processed using scanning line selection technology; The grid line spacing in the transition area is adjusted to a change step of 5 μm, and the transition radius is 150 to 200 μm.

6. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The width of the gate lines in the equal-spaced area is 10-15 μm, the gate line spacing is 30-50 μm, and the depth of the gate line slots is 3-5 μm.

7. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The width of the gate lines in the non-uniformly spaced region is 8 to 12 μm, the range of the gate line spacing is 30 to 100 μm, and the variation of the spacing is distributed according to an exponential or linear rule.

8. The process for producing a knotless screen with both equally spaced and non-equally spaced grid lines according to claim 1, characterized in that: The grid line spacing variation step length in the transition region is 5 μm, and the grid line transition radius is 100-200 μm.

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