Oblique staggered metal mesh screen printing plate

Abstract

The utility model discloses an oblique staggered metal mesh silk-screen printing plate which comprises a screen frame, a metal mesh and a printing plate wire groove, the metal mesh is tensioned on the screen frame through a tensioning wire mesh, the printing plate wire groove is arranged on the metal mesh, the metal mesh is formed by interweaving variable-pitch silk threads and equidistant silk threads in a crossed mode, and the printing plate wire groove is arranged on the printing plate wire groove. The cross included angle alpha between the variable-pitch silk threads and the equidistant silk threads is 75-85 degrees; the printing plate wire groove is located between two adjacent variable-pitch silk threads, and one groove side or two groove sides of at least one printing plate wire groove are provided with two variable-pitch silk threads which are close to each other. The two variable-pitch silk threads close to each other comprise offset silk threads and weaving silk threads, and the offset silk threads are formed by offsetting the weaving silk threads. And the printing plate wire groove is parallel to the variable-pitch silk thread. The diameter of the variable-pitch silk threads and the diameter of the equidistant silk threads range from 6 micrometers to 10 micrometers. The screen printing plate not only can prevent silk threads from crossing a screen to form an existing screen printing wire slot area, but also can ensure the tensile strength of a silk screen of the screen printing plate and the shaping completeness of printed grid lines.

Description

Technical Field

[0001] The utility model relates to a printing screen for a solar photovoltaic cell, in particular to a printing screen for a solar photovoltaic cell sheet without mesh knots by offsetting the placement of mesh wires. Background Art

[0002] The power generation efficiency of a solar photovoltaic cell sheet is directly related to the shape and quality of the conductive grid lines thereon, and the conductive grid lines are printed by a printing screen; since the printing screen uses a metal woven mesh, there are overlapping intersections at the intersections of the warp and weft of the metal wire mesh to form mesh knots, which have a relatively large obstruction to the ink or slurry, reducing the ink permeability of the printing screen. Therefore, it is required that the ink or slurry has good rheology in order to bypass the mesh knots and fuse together during the printing process, so as not to form problems such as broken grids or rough edges of the solar cell; in order to minimize the influence brought by the mesh knots, currently, the metal wires in the warp or weft direction of the printing pattern are removed, and the fine grid pattern is arranged in the grid without mesh knots during pattern making. Although such a meshless screen improves the printability of the fine grid, the process of removing the steel wire requires about 20-30 minutes of cutting with a laser machine to cut off the steel wire, and then the steel wire residues are washed off through steps such as water washing to ensure that all the steel wires have been removed. At the same time, the screen also needs to be inspected to prevent the screen from being scrapped due to incomplete removal of residues; at the same time, during the laser cutting process, due to reasons such as equipment stability, incorrect parameter settings, and irregular shapes of the grids in the mesh cloth, the laser may also cut off the steel wires in the other direction, resulting in screen rupture.

[0003] In order to ensure the photosensitive area on the surface of the photovoltaic cell sheet, it is desirable that the width of the printed conductive grid line is as thin as possible. Currently, the wire diameter of high-quality and high-precision printing screens has reached below 10μm. The mesh cloth used for the current solar cell sheet printing screen has a 90-degree angle between the warp and weft. When making the above-mentioned meshless screen, the mesh knots in the pattern printing area are removed, so the mesh yarns in the printing groove opening form a 90-degree angle with the long direction of the groove. Such a screen is limited by the rheology of the conductive paste during printing. In the scraping path of the printing squeegee, it will constantly encounter the obstruction of the mesh yarns in the groove, affecting the extrusion effect of the squeegee on the slurry, and it is easy to have incomplete shaping under the obstruction of the mesh wires, and it is difficult to ensure the printing precision. It is easy to have irregular shapes or even broken lines of the conductive grid lines, resulting in printing defects of the finally produced cell sheet and affecting the power generation efficiency of the cell sheet. At the same time, using the method of laser cutting the steel wire, on the one hand, due to the reduction of the number of steel wires, it will affect the tensile strength of the wire mesh, and it is easy to have cracked or broken screens during repeated printing, resulting in screen scrapping, shortening the service life of the screen, and increasing the printing cost; on the other hand, for ultra-fine and extremely fine metal wire meshes, it increases the difficulty of laser cutting, as well as the risk of mis-cutting and the difficulty of removing the cut wires. Summary of the Utility Model

[0004] In view of the above deficiencies in the prior art, the technical problem to be solved by the present utility model is to provide an obliquely staggered metal wire screen printing stencil, which can avoid silk thread intersections and knots in the printing groove area of the stencil, and ensure the tensile strength of the stencil wire mesh and the integrity of the gate line shaping.

[0005] To solve the above technical problem, the obliquely staggered metal wire screen printing stencil of the present utility model includes a screen frame, a metal wire mesh and a printing plate groove. The metal wire mesh is tensioned on the screen frame through a tensioned wire mesh. The printing plate groove is arranged on the metal wire mesh. The metal wire mesh is woven by alternately arranged variable pitch wires and equally spaced wires, and the crossing angle α between the variable pitch wires and the equally spaced wires is 75° - 85°; the printing plate groove is located between two adjacent variable pitch wires, and at least one groove side or both groove sides of the printing plate groove are provided with two mutually adjacent variable pitch wires.

[0006] In the above structure, since the printing plate groove is located between two adjacent variable pitch wires, it is ensured that the printing plate groove is always located between two warp or weft wires, forming a knot-free printing plate structure. There are no warp and weft wire crossing nodes in the printing plate groove, reducing the printing resistance to the printing paste, and ensuring the ink permeability and printing quality of the printing stencil; and by arranging two mutually adjacent variable pitch wires on the groove side of the printing plate groove, there is no need to remove the warp or weft wires forming the cross knot by laser cutting, and there will be no residual cutting wires affecting the printing quality, nor will there be accidental cutting of adjacent wires by the laser resulting in stencil rupture; especially this structure can form mutually adjacent variable pitch wires by offsetting specific wires of the equally spaced woven mesh cloth without reducing the number of mesh wires of the mesh cloth, thus ensuring sufficient tensile strength of the stencil mesh surface, and is particularly suitable for printing stencils of extremely fine and ultra-fine wire meshes. Also, since the crossing angle α between the variable pitch wires and the equally spaced wires is 75° - 85°, the hindrance of the mesh yarn in the groove to the printing squeegee is reduced, ensuring a good extrusion effect of the squeegee on the paste, which is beneficial to the complete shaping of the printed gate line and higher printing precision; at the same time, controlling the crossing angle of the warp and weft wires within the above range will not have a negative impact on the tensile strength of the stencil.

[0007] In a preferred embodiment of the present utility model, the two mutually adjacent variable pitch wires include an offset wire and a woven wire. The offset wire is formed by offsetting the woven wire, and the woven wires are arranged at equal intervals. The printing plate groove is parallel to the variable pitch wire. The wire diameters of the variable pitch wire and the equally spaced wire are 6μm - 10μm. This structure not only ensures that there are no knots formed by the crossing of warp and weft wires in the printing plate groove, but also maintains the tensile strength of the metal wire mesh unchanged; it is particularly suitable for the wire mesh of extremely fine or ultra-fine wire meshes.

[0008] In a preferred embodiment of the present utility model, the crossing angle α between the variable pitch wire and the equidistant wire is 80°. This can not only ensure the complete shaping of the printed grid line but also not affect the tensile strength of the screen plate.

[0009] In a preferred embodiment of the present utility model, a scraping side film layer is coated on the scraping side of the metal wire mesh, and a plurality of scraping side wire grooves are arranged on the scraping side film layer. A printing side film layer is coated on the printing side of the metal wire mesh, and a plurality of printing side wire grooves are arranged on the printing side film layer. The groove opening width of the scraping side wire groove is greater than the groove opening width of the printing side wire groove. The scraping side film layer and the printing side film layer are a polymer thin film adhesive layer and / or a photosensitive glue coating layer. A material-containing structure with a stepped opening is formed. The silver paste located in the stepped opening groove can be directly scraped out of the printing film wire groove, thereby reducing the penetration resistance of the wire mesh to the printing paste. At the same time, when the squeegee is scraping, it can generate a certain printing extrusion pressure on the paste in the stepped opening groove, promoting the transfer of the paste in the printing plate wire groove to the printing substrate.

[0010] In a preferred embodiment of the present utility model, an intermediate film layer is coated on the printing side of the metal wire mesh, and a printing side film layer is coated on the intermediate film layer. A plurality of intermediate film layer wire grooves are arranged on the intermediate film layer, and a plurality of printing side wire grooves are arranged on the printing side film layer. The groove opening width of the intermediate film layer wire groove is greater than the groove opening width of the printing side wire groove. The intermediate film layer and the printing side film layer are a polymer thin film adhesive layer and / or a photosensitive glue coating layer. A material-containing structure with a stepped opening is formed. The silver paste located in the stepped opening groove can be directly scraped out of the printing film wire groove, thereby reducing the penetration resistance of the wire mesh to the printing paste. At the same time, when the squeegee is scraping, it can generate a certain printing extrusion pressure on the paste in the stepped opening groove, promoting the transfer of the paste in the printing plate wire groove to the printing substrate. Description of the Drawings

[0011] The following further elaborates on the inclined cross metal wire screen printing plate of the present utility model in conjunction with the drawings and specific embodiments.

[0012] Figure 1 It is a schematic structural diagram of a specific embodiment of the inclined cross metal wire screen printing plate of the present utility model;

[0013] Figure 2 It is Figure 1 A partial enlarged view of the wire mesh surface of part I in

[0014] Figure 3 It is Figure 1 A specific structural enlarged view of the cross-section of the wire mesh in

[0015] Figure 4 It is Figure 1 Another specific structural enlarged view of the cross-section of the wire mesh in

[0016] In the figure, 1 is a screen frame, 2 is a stretched wire mesh, 3 is a wire mesh, 4 is a printing plate wire groove, 5 is a variable pitch wire, 51 is an offset wire, 52 is a braided wire, 6 is an equidistant wire, 7 is a squeegee side film layer, 8 is a sticking side film layer, 9 is a squeegee side wire groove, 10 is a sticking side wire groove, 11 is an intermediate film layer, and 12 is an intermediate film layer wire groove. Specific implementation mode

[0017] As Figure 1 shown, the inclined cross metal wire screen printing screen plate includes a screen frame 1, and the screen frame 1 is a rectangular aluminum frame member in a return shape. A wire mesh 3 made of stainless steel is tensioned at the center position of the screen frame 1, and a stretched wire mesh 2 is bonded to the four sides of the wire mesh 3. The stretched wire mesh 2 is a polyester mesh, and the bonding ends extending outward from the four sides of the stretched wire mesh 2 are fixedly bonded to the bottom surfaces of the four sides of the screen frame 1. The printing plate wire groove 4 for printing the conductive grid lines of the battery chip is arranged on the wire mesh 3.

[0018] As Figure 2 shown, the wire mesh 3 is woven by intersecting variable pitch wires 5 and equidistant wires 6. The variable pitch wires 5 and the equidistant wires 6 are stainless steel wires with a wire diameter between 6μm and 10μm, or can be nickel wires. And the crossing angle α between the variable pitch wire 5 and the equidistant wire 6 is 80°; through repeated experimental comparisons, the applicant controls the crossing angle α between 75° and 85°, which can achieve the comprehensive effect of complete shaping of the grid lines without affecting the tensile strength of the screen plate. In Figure 2 it, the weft wires are equidistant wires 6, and the warp wires are variable pitch wires 5. The variable pitch wire 5 includes a braided wire 52 and an offset wire 51, and the offset wire 51 is formed by offsetting the braided wire 52; when a certain warp wire (as shown by the dotted line in the figure) happens to be located at the position of the printing plate wire groove 4 and intersects with the weft equidistant wire 6 to form a mesh knot, an offset comb with several comb needles is required to deflect and shift the warp wire to be close to another warp wire to form a wire merging structure. These two mutually close variable pitch wires 5 include an offset wire 51 formed by deflection and shifting, and the other is the braided wire 52 during screen weaving, and the braided wires 52 during weaving are equidistantly arranged. The printing plate wire groove 4 is parallel to the variable pitch wire 5.

[0019] As Figure 3As shown in the figure, a scraping-side film layer 7 is coated on the scraping-side G surface of the wire mesh 3, and the scraping-side film layer 7 is formed by coating and photosensitizing photosensitive latex. The outer surface of the scraping-side film layer 7 is the scraping surface. During scraping, the blade directly contacts the scraping surface. A number of scraping-side wire grooves 9 are designed on the scraping-side film layer 7 according to the printing pattern, and the cross-section of the scraping-side wire groove 9 is a rectangular through groove. A printing-side film layer 8 is coated on the lower surface of the printing-side T of the wire mesh 3, and the printing-side film layer 8 is pasted by polymer films such as PET, PE, PI, PU, PVC, and PS. A number of printing-side wire grooves 10 are also designed on the printing-side film layer 8 according to the printing pattern. The groove center lines of the corresponding scraping-side wire grooves 9 and printing-side wire grooves 10 are located on the same straight line, and the groove width of the scraping-side wire groove 9 is greater than the groove width of the printing-side wire groove 10, so as to form a printing plate wire groove 4 with a stepped cross-section, which is beneficial to improving the ink penetration performance of printing, improving the printing quality, and more beneficial to improving the aspect ratio of the printed electrode paste, which is beneficial to reducing the light-shielding area of the printed grid lines and can effectively reduce the consumption of the printed paste.

[0020] As Figure 4 shown in the figure, an intermediate film layer 11 is coated on the printing-side (T) of the wire mesh 3, and the intermediate film layer 11 is formed by coating and photosensitizing photosensitive latex. A number of intermediate film layer wire grooves 12 are designed on the intermediate film layer 11 according to the printing pattern, and the cross-section of the intermediate film layer wire groove 12 is a rectangular through groove. A printing-side film layer 8 is coated on the intermediate film layer 11, and the printing-side film layer 8 is pasted by polymer films such as PET, PE, PI, PU, PVC, and PS. A number of printing-side wire grooves 10 are provided on the printing-side film layer 8, and the groove width of the intermediate film layer wire groove 12 is greater than the groove width of the printing-side wire groove 10, so as to form a printing plate wire groove 4 with a stepped cross-section. The above intermediate film layer 11 and printing-side film layer 8 can be a polymer film paste layer or a photosensitive glue coating layer.

[0021] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

Claims

1. An inclined cross metal wire screen printing stencil, comprising a screen frame (1), a metal wire mesh (3) and a printing plate wire groove (4), wherein the metal wire mesh (3) is tensioned on the screen frame (1) through a tensioning wire mesh (2), and the printing plate wire groove (4) is arranged on the metal wire mesh (3), and is characterized in that: The metal wire mesh (3) is woven by the variable pitch wires (5) and the equal pitch wires (6) crossing each other, and the crossing angle α between the variable pitch wires (5) and the equal pitch wires (6) is 75° - 85°; the printing plate wire grooves (4) are located between two adjacent variable pitch wires (5), and on at least one groove side or both groove sides of at least one of the printing plate wire grooves (4), there are two variable pitch wires (5) close to each other.

2. The inclined cross metal wire screen printing stencil according to claim 1, characterized in that: The two variable pitch wires (5) close to each other include a offset wire (51) and a weaving wire (52), the offset wire (51) is formed by offsetting the weaving wires, and the weaving wires (52) are arranged at equal intervals.

3. The inclined staggered metal wire screen printing stencil according to claim 1 or 2, characterized in that: The printing plate wire grooves (4) are parallel to the variable pitch wires (5).

4. The inclined staggered metal wire screen printing stencil according to claim 1 or 2, characterized in that: The wire diameters of the variable pitch wires (5) and the equal pitch wires (6) are 6μm - 10μm.

5. The inclined staggered metal wire screen printing stencil according to claim 1 or 2, characterized in that: The crossing angle α between the variable pitch wires (5) and the equal pitch wires (6) is 80°.

6. The inclined cross metal wire screen printing stencil according to claim 1, characterized in that: The printing side (G) of the metal wire mesh (3) is coated with a printing side film layer (7), and a number of printing side wire grooves (9) are provided on the printing side film layer (7), the printing side (T) of the metal wire mesh (3) is coated with a printing side film layer (8), and a number of printing side wire grooves (10) are provided on the printing side film layer (8), and the groove opening width of the printing side wire grooves (9) is greater than the groove opening width of the printing side wire grooves (10).

7. The inclined staggered metal wire screen printing stencil according to claim 6, wherein: The printing side film layer (7) and the printing side film layer (8) are a polymer film pasting layer and / or a photosensitive glue coating layer.

8. The inclined cross metal wire screen printing stencil according to claim 1, wherein: The printing side (T) of the metal wire mesh (3) is coated with an intermediate film layer (11), the printing side film layer (8) is coated on the intermediate film layer (11), a number of intermediate film layer wire grooves (12) are provided on the intermediate film layer (11), a number of printing side wire grooves (10) are provided on the printing side film layer (8), and the groove opening width of the intermediate film layer wire grooves (12) is greater than the groove opening width of the printing side wire grooves (10).

9. The inclined staggered metal wire screen printing stencil according to claim 8, characterized in that: The intermediate film layer (11) and the printing side film layer (8) are a polymer film pasting layer and / or a photosensitive glue coating layer.

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