Precise printing screen

Abstract

The utility model relates to the technical field of screen printing, and discloses a precise printing screen which comprises a screen frame and a screen body tensioned in the screen frame, the screen body comprises a printing area and tension adjusting areas located on the two sides of the printing area, the printing area is provided with grid lines, and the tension adjusting areas are located on the two sides of the printing area. A fixed deviation angle beta is arranged between the longitudinal extending axis of the tension adjusting area and the extending direction of the grid lines in the printing area, and beta is larger than or equal to 0.1 degree and smaller than or equal to 10 degrees. According to the utility model, a transverse expansion vector generated by a deviation angle beta actively compensates the inward contraction of a printing area caused by Poisson effect, thereby fundamentally solving the problem of arc deformation of'center concave 'of the grid line, and controlling the straightness tolerance of the whole grid line within 20 [mu] m. Due to the design of the deviation angle, the contact point of the scraper pressure and the tension adjusting area smoothly moves along with time, instantaneous impact force is converted into multi-path progressive dispersion, direct sudden change of tension is avoided, a tension fluctuation curve is smoother, and printing chatter marks and slurry overflow are remarkably reduced.

Description

Technical Field

[0001] This utility model relates to the field of screen printing technology, specifically to a precision printing screen. Background Technology

[0002] As photovoltaic cell technology advances towards processes like Topcon and HJT that employ ultra-fine grid lines (e.g., linewidth less than 15μm), higher demands are placed on the tension stability and line shape control of printing screens. Current technologies typically set tension adjustment zones parallel to the grid line extension direction on both sides of the printing area, passively absorbing the squeegee pressure during printing by filling with flexible materials or setting up a perforated mesh. However, this traditional structure has the following significant drawbacks:

[0003] Instantaneous stress impact: Since the tension adjustment zone is parallel to the direction of squeegee movement, the pressure of the squeegee pressing down will act on the tension adjustment zone simultaneously along the entire line, causing an instantaneous change in tension. This "full-line contact" can easily trigger high-frequency resonance of the screen, which in turn causes the printing paste to spread and burrs on the grid line edges.

[0004] Dimensional distortion caused by the Poisson effect: When a traditional screen printing plate is subjected to tensile tension along the grid line direction, based on the positive Poisson's ratio characteristic of the material, the central area of ​​the printing area will produce inward lateral contraction. With the tension areas on both sides completely parallel to the grid line, this contraction force cannot be effectively offset, causing the grid line to bend towards the center, forming an obvious "arc line" error, which seriously affects the alignment accuracy of multiple processes and the photoelectric conversion efficiency of the final solar cell. Utility Model Content

[0005] The purpose of this invention is to provide a precision printing screen that solves the problems of Poisson shrinkage and "arc line" deformation caused by the parallel layout of the tension adjustment zone and the grid lines in the prior art.

[0006] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0007] This utility model is a precision printing screen, including a screen frame and a screen body tensioned therein. The screen body includes a printing area and tension adjustment areas located on both sides of the printing area. The printing area is provided with grid lines. A fixed deviation angle β is provided between the longitudinal extension axis of the tension adjustment area and the extension direction of the grid lines in the printing area, and 0.1°≤β≤10°.

[0008] The tension adjustment zone utilizes a fixed deviation angle β to generate an outward lateral force when the screen is subjected to tension along the extension direction of the grid lines, in order to compensate for the inward shrinkage displacement of the printing area caused by the Poisson effect.

[0009] Furthermore, the geometry of the tension adjustment area is any one of a rectangle, an arc shape that is wide in the middle and narrow at both ends, or a V-shape. The geometry includes, but is not limited to, these three shapes, and the tension adjustment area is arranged in a non-parallel mirror symmetric arrangement with the central axis of the printing area.

[0010] Furthermore, the deviation angle β is taken as the progressive strain response generated by the tension adjustment zone during the movement of the printing squeegee, which transforms the instantaneous full-line contact pressure of the squeegee downward into a dynamic load from point to line.

[0011] Furthermore, the tension adjustment zone is made of a double-layer or multi-layer adhesive film composite structure, wherein the adhesive film is composed of two or more of PE, EVA, TPU, PO, PES, and EAA.

[0012] Furthermore, when the tension adjustment area is V-shaped or arc-shaped, the lateral width of the tension adjustment area near its longitudinal center is greater than its lateral width near its longitudinal ends.

[0013] Furthermore, the mesh body is composed of metal mesh or composite fiber mesh, wherein the metal mesh includes steel wire mesh, alloy mesh, electroformed mesh or laser-cut mesh.

[0014] Furthermore, the tension adjustment zone guides the excess stress in the printing area obliquely to the four corners of the screen frame.

[0015] Furthermore, the composite interface between the mesh body and the tension adjustment zone forms an oblique boundary line with the grid line at a fixed deviation angle β.

[0016] Furthermore, the mold thickness of the tension adjustment zone is 10-100μm, and the surface has a release effect, which facilitates demolding and prevents the adhesive film from sticking.

[0017] Furthermore, the thickness of the tension adjustment zone is 80-300μm, and its overall physical modulus is lower than that of the printing zone.

[0018] This utility model has the following beneficial effects:

[0019] (1) This utility model actively compensates for the inward shrinkage of the printing area caused by the Poisson effect by the lateral expansion vector generated by the deviation angle β, fundamentally solving the problem of arc deformation of the grid line "concave center". The straightness tolerance of the grid line of the whole plate can be controlled within 20μm. The deviation angle design makes the contact point between the squeegee pressure and the tension adjustment area move smoothly over time, transforming the instantaneous impact force into multi-path gradual dispersion, avoiding direct abrupt change in tension. The overall tension distribution of the screen can be reduced to below 1.0N / cm, the tension fluctuation curve is smoother, and printing tremors and paste overflow are significantly reduced.

[0020] (2) This utility model effectively eliminates local stress concentration, reduces the deformation rate of fine grids, and can stably extend the service life of the screen to more than 150,000 times. It avoids the fluctuation of mesh opening rate caused by screen deformation, and improves the uniformity of printed grid line height by about 15%, which helps to reduce the series resistance of the battery cell.

[0021] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the rectangular mold for the tension adjustment area in this utility model.

[0024] Figure 2 This is a schematic diagram of the structure of the tension adjustment area mold in this utility model, which is a ring shape that is wide in the middle and narrow at both ends;

[0025] Figure 3 This is a schematic diagram of the V-shaped structure of the tension adjustment area mold in this utility model;

[0026] The attached diagram lists the components represented by each number as follows:

[0027] In the diagram: 1. Screen frame; 2. Screen body; 201. Printing area; 202. Tension adjustment area; 203. Grid lines. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1:

[0030] In this embodiment, as shown in the appendix Figure 1As shown, the tension adjustment area 202 adopts a rectangular geometric shape. By setting the positioning angle of the tension area mold, the deviation angle β is set between 1° and 3.5°. Under a printing tension of 12 N / cm, the lateral tension vector generated by this deviation angle can compensate for more than 90% of the Poisson necking displacement. During production, the polyester mesh is first stretched on the dummy frame and glued firmly; then the rectangular tension adjustment area mold is placed at a 2° angle with the grid line 203 in the fixed position of the dummy frame fixture, and the adhesive film, the pre-designed mesh fabric, and the release paper are laid in sequence and placed in the laminating machine for lamination; after lamination, the polyester mesh in the tension adjustment area 202 and the mesh fabric pattern area is cut off; finally, the screen is pushed to the working frame and tensioned to the required tension.

[0031] Example 2:

[0032] In this embodiment, as shown in the appendix Figure 2 As shown, the tension adjustment zone 202 adopts an arc-shaped structure that is wide in the middle and narrow at both ends, and is equipped with a 1° micro-angle. This design further provides differentiated stress relief feedback for the stress concentration in the central area of ​​the large-size battery screen, effectively solving the problem that the center of the screen is prone to "collapse". The manufacturing process is similar to that of Example 1, except that an arc-shaped mold is used and the initial screen fabric does not have a preset pattern. The pattern is made in the subsequent hot pressing film and laser cutting process.

[0033] Example 3:

[0034] In this embodiment, as shown in the appendix Figure 3 As shown, the tension adjustment zone 202 adopts a V-shaped structure. One side of the mold is placed in the positioning frame with an angle of 3° with the grid line 203. The adhesive film is placed on it, and the mesh fabric is placed on the corresponding position on the adhesive film. The mesh fabric has a pre-set pattern. Then the release paper is placed and put into the laminating machine to complete the lamination. After the lamination is completed, the polyester mesh in the tension adjustment zone 202 is cut off, and the polyester mesh in the mesh fabric area is also cut off. The tension top frame is completed according to the requirements.

[0035] The production process includes the following steps:

[0036] Tensioning the dummy frame: Stretch the polyester mesh to the specified tension and glue it firmly to the dummy frame;

[0037] Lamination: Make tension adjustment zone 202, place the dummy frame on the fixture, place the tension adjustment zone 202 mold in the fixed position of the dummy frame, place the adhesive film, place the mesh fabric on the corresponding position on the adhesive film, then place the release paper, put it into the laminating machine, after lamination is completed, cut off the polyester mesh in tension adjustment zone 202, and cut off the polyester mesh in the mesh fabric area;

[0038] Top frame: Apply tension to the top frame as needed, then apply tape to the four sides. The pre-set graphic screen is now complete. Screens without pre-set graphics require graphic creation in subsequent processes.

[0039] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A precision printing screen, comprising a screen frame (1) and a screen body (2) tensioned therein, the screen body (2) comprising a printing area (201) and tension adjustment areas (202) located on both sides of the printing area (201), the printing area (201) being provided with grid lines (203), characterized in that: The longitudinal extension axis of the tension adjustment area (202) is provided with a fixed deviation angle β between it and the extension direction of the grid line (203) in the printing area (201), and 0.1°≤β≤10°; The tension adjustment zone (202) utilizes a fixed deviation angle β to generate an outward lateral force when the screen is subjected to tension along the extension direction of the grid line (203), in order to compensate for the inward displacement of the printing area (201) caused by the Poisson effect.

2. The precision printing screen according to claim 1, characterized in that: The tension adjustment area (202) has a geometric shape that is rectangular, arc-shaped with a wide middle and narrow ends, or V-shaped. The geometric shape includes, but is not limited to, these three shapes. The tension adjustment area (202) and the printing area (201) are arranged in a non-parallel mirror symmetric manner along their central axes.

3. The precision printing screen according to claim 1, characterized in that: The deviation angle β is the value of the tension adjustment zone (202) generating a progressive strain response during the movement of the printing squeegee, which transforms the instantaneous full-line contact pressure of the squeegee downward into a dynamic load from point to line.

4. A precision printing screen according to claim 1, characterized in that: The tension adjustment zone (202) is made of a double-layer or multi-layer adhesive film composite structure, and the adhesive film is composed of two or more of PE, EVA, TPU, PO, PES and EAA.

5. A precision printing screen according to claim 2, characterized in that: When the tension adjustment area (202) is V-shaped or arc-shaped, the lateral width of the tension adjustment area (202) near its longitudinal center is greater than its lateral width near its longitudinal ends.

6. The precision printing screen according to claim 1, characterized in that: The mesh body (2) is composed of metal mesh or composite fiber mesh, wherein the metal mesh includes steel wire mesh, alloy mesh, electroformed mesh or laser-cut mesh.

7. A precision printing screen according to claim 1, characterized in that: The tension adjustment zone (202) is designed to guide the excess stress of the printing zone (201) obliquely to the four corners of the frame (1).

8. A precision printing screen according to claim 1, characterized in that: The composite interface between the mesh body (2) and the tension adjustment zone (202) and the grid line (203) forms an oblique boundary line with a fixed deviation angle β.

9. A precision printing screen according to claim 1, characterized in that: The mold thickness of the tension adjustment zone (202) is 10-100μm, and the surface has a release effect, which facilitates demolding and prevents the adhesive film from sticking.

10. A precision printing screen according to claim 1, characterized in that: The thickness of the tension adjustment area (202) is 80-300μm, and its overall physical modulus is lower than that of the printing area (201).

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