TW201918380A - Screen stencil and screen printing method - Google Patents

Abstract

A screen stencil and a screen printing method are described. The screen stencil includes a screen mesh and a blocking layer. The screen mesh includes a plurality of first wires extending along a first direction and a plurality of second wires along a second direction. An included angle between the first direction and the second direction is not a right angle. The blocking layer is adhered to the screen mesh, and includes a first paste hole and a plurality of second paste holes. A width of the first paste hole is greater than a width of each of the second paste holes. The second paste holes extend along the second direction, and the second paste holes and the second wires do not overlap. An extending direction of the first past hole is perpendicular to the second direction.

Description

 Screen and screen printing method  

This invention relates to a printing technique and, more particularly, to a screen and screen printing method.

The light-receiving electrodes of today's solar cells typically comprise a wider busbar electrode and a relatively narrow finger electrode. In order to further reduce the width of the finger electrodes, the industry has adopted the method of screenless screen printing for screen printing.

Generally, the screen printing screen for solar cell electrodes comprises a mesh cloth and a barrier layer woven from steel wires orthogonal to the latitude and longitude lines, wherein the barrier layer is disposed on the mesh cloth. The barrier layer has an ink drop opening of the orthogonal bus electrode and a drop ink opening of the plurality of finger electrodes. The common meshless screen is designed such that one of the warp and weft of the mesh and the ink drop opening of the finger electrode are parallel but do not overlap to prevent the mesh from appearing in the ink drop opening of the finger electrode.

During the screen printing process of the solar cell electrodes, the doctor blade moves in the extending direction of the ink drop opening of the parallel finger electrodes, and the extending direction of the scraping surface of the doctor blade is the moving direction of the vertical blade. However, in the screen printing process using the meshless screen, since the extending direction of the scraping surface of the scraper is parallel with one of the warp and weft of the mesh, the ink drop of the screen printing is uneven, that is, the partial area is inked. Poor, and it is easy for the bus electrode to appear exposed due to incomplete coverage.

In addition, in order to alleviate the influence of possible disconnection of the finger electrodes, the light-receiving surface electrodes of solar cells are often provided with auxiliary electrodes connected to the fingers. The width of the auxiliary electrode is generally similar to that of the finger electrode, and the direction of extension is generally perpendicular to the direction in which the finger electrodes extend. However, in the design of the conventional meshless screen, the extending direction of the auxiliary electrode is parallel to one of the warp and weft of the mesh of the mesh, and the mesh may appear in the ink drop hole of the auxiliary electrode. The slurry that seriously affects the area of the auxiliary electrode is dropped, which in turn leads to a decrease in production yield.

Therefore, an object of the present invention is to provide a screen and screen printing method in which one of the warp and the weft of the mesh is parallel to the ink drop of the finger electrode and does not overlap, and the other of the warp and the weft The ink drop holes of the electrodes are oblique. In the case of screen printing, the moving direction of the blade can be parallel to the direction in which the ink holes of the finger electrodes extend, so that the conventional screen blade can be used without greatly modifying the existing machine.

Another object of the present invention is to provide a screen printing and screen printing method, wherein the extending direction of the scraping surface of the blade is also the extending direction of the ink collecting holes of the bus electrode and the auxiliary electrode, and the warp and the weft of the mesh are not parallel. Therefore, the problem that the conventional no-wire network version is easy to generate uneven charging of the bus electrode and the auxiliary electrode during the screen printing can be effectively solved, thereby greatly improving the yield of the printing process without the net-screen version.

Another object of the present invention is to provide a screen printing and screen printing method, wherein the direction of the ink drop of the auxiliary electrode of the screen is not parallel to the warp and weft of the mesh, so that the warp and weft are not easily occupied. In the case of the ink drop hole of the auxiliary electrode, the influence of the warp and weft on the ink drop of the auxiliary electrode region can be reduced.

According to the above object of the present invention, a screen is proposed. This screen includes a mesh and a barrier. The mesh comprises a plurality of first meshes extending in a first direction and a plurality of second meshes extending in a second direction. The angle between the first direction and the second direction is not a right angle. The barrier layer is attached to the mesh and includes a first ink drop hole and a plurality of second ink drop holes, and the width of the first ink drop holes is greater than the width of each of the second ink drop holes. The second ink drop holes extend in the second direction, and the second ink drop holes and the plurality of second mesh wires do not overlap, and the first ink drop holes extend in a direction perpendicular to the second direction.

According to an embodiment of the invention, the acute angle between the first direction and the second direction is 55 degrees to 75 degrees.

According to an embodiment of the invention, the acute angle between the first direction and the second direction is 60 degrees to 68 degrees.

According to an embodiment of the invention, the barrier layer further includes a third ink drop hole, the width of the third ink drop hole is smaller than the width of the first ink drop hole, and the third ink drop hole extends in parallel with the first ink drop hole.

According to an embodiment of the invention, the third ink drop hole is connected to the ends of the at least two second ink drop holes.

According to an embodiment of the invention, the third ink drop hole is connected to at least two of the second ink drop holes.

According to the above object of the present invention, a screen printing method is further proposed. In this method, a screen printing process is performed using a doctor blade and the above-described screen to form a paste pattern layer on the substrate via the definition of the ink drop area of the screen. When the screen printing process is performed, the moving direction of the blade is parallel to the second direction.

According to an embodiment of the present invention, when the screen printing process is performed, the direction of the scraping surface of the blade is perpendicular to the second direction.

According to an embodiment of the invention, the substrate is a substrate of a solar cell, the slurry pattern layer is a conductive paste layer on the light receiving surface of the solar cell, and the first ink drop hole is used to define the shape of the bus electrode of the conductive paste layer. A plurality of second ink holes are used to define the shape of the plurality of finger electrodes of the conductive paste layer.

100‧‧‧Web Edition

102‧‧‧Part 1

104‧‧‧Part II

110‧‧‧Mesh

112‧‧‧First mesh

114‧‧‧Second mesh

120‧‧‧Block

130‧‧‧First direction

132‧‧‧second direction

140‧‧‧The first ink hole

140w‧‧‧Width

150‧‧‧Second ink hole

End of 150e‧‧

150w‧‧‧Width

160‧‧‧The third ink hole

160w‧‧‧Width

170‧‧‧ scraper

170m‧‧‧ moving direction

172‧‧‧Scrape

172e‧‧‧Scratch direction

180‧‧‧Substrate

180a‧‧‧ surface

190‧‧‧Slurry pattern layer

192‧‧‧Concurrent electrode

194‧‧‧ finger electrodes

196‧‧‧Auxiliary electrode

Θ‧‧‧ acute angle

The above and other objects, features, advantages and embodiments of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; FIG. 2 is a partially enlarged schematic view showing the mesh of the screen shown in FIG. 1; FIG. 3 is a partially enlarged schematic view showing the first portion of the screen shown in FIG. FIG. 4 is a partially enlarged schematic view showing a second portion of the screen shown in FIG. 1; FIG. 5 is a schematic diagram showing a screen printing method according to an embodiment of the present invention. FIG. 6 is a schematic top view of a screen printed substrate according to an embodiment of the present invention.

1 and FIG. 2, FIG. 1 is a schematic top view of a screen according to an embodiment of the present invention, and FIG. 2 is a partially enlarged schematic view of the screen of the screen shown in FIG. In some embodiments, the screen 100 includes a mesh 110 and a barrier layer 120. As shown in FIG. 2, the mesh 110 includes a plurality of first mesh wires 112 and a plurality of second mesh wires 114. The first mesh 112 extends in a first direction 130 and the second mesh 114 extends in a second direction 132 that interweaves to form a mesh 110. The angle between the first direction 130 and the second direction 132 is not a right angle, that is, the angle between the first mesh 112 and the second mesh 114 is not a right angle. In some examples, the acute angle θ between the first direction 130 and the second direction 132 is between about 55 degrees and about 75 degrees. In some exemplary examples, the acute angle θ is from about 60 degrees to about 68 degrees.

The wire diameter of the first wire 112 and the second wire 114 may be the same. In some particular examples, the wire diameter of the first wire 112 and the second wire 114 can be different. In addition, the wire diameters of the first mesh wires 112 may be the same as each other, and may be different or different. The wire diameters of the second mesh wires 114 may be the same as each other, and may be different or different. In some examples, the first mesh wires 112 can be arranged in an equidistant manner, and the second mesh wires 114 can also be arranged in an equidistant manner. In some specific examples, the arrangement of the first mesh 112 and the second mesh 114 may also be non-equidistant.

Please refer to FIG. 3 and FIG. 4 together, wherein FIG. 3 and FIG. 4 are respectively partially enlarged schematic views showing the first portion and the second portion of the screen shown in FIG. 1. The barrier layer 120 is attached to the mesh 110. In some examples, as shown in FIG. 1, the barrier layer 120 includes at least one first ink drop hole 140 and a plurality of second ink drop holes 150. The direction of extension of the first ink drop hole 140 is perpendicular to the second direction 132, and each of the second ink drop holes 150 extends along the second direction 132, that is, the direction in which each of the second ink drop holes 150 extends is parallel to the second direction 132. Therefore, the second ink drop hole 150 is perpendicular to the first ink drop hole 140. In addition, the second ink drop hole 150 and the second mesh wire 114 do not overlap, so that no netting occurs in the second ink drop hole 150, so the screen 100 can also be referred to as a meshless screen.

As shown in the enlarged schematic view of the first portion 102 of the screen 100 of FIG. 3, the width 140w of the first ink drop hole 140 is greater than the width 150w of each second ink drop hole 150. In these examples, the first ink drop hole 140 is configured to make a bus electrode, and the second ink drop hole 150 is configured to make a finger electrode. Since each solar cell may include a plurality of bus electrodes, the barrier layer 120 may be correspondingly provided with a plurality of first ink holes 140.

In some examples, as shown in FIG. 1 , the barrier layer 120 can further include a third ink drop hole 160 . The extending direction of the third ink drop hole 160 may be parallel to the first ink drop hole 140, and thus the third ink drop hole 160 extends in a direction perpendicular to the second direction 132. As shown in the enlarged schematic view of the second portion 104 of the screen 100 of FIGS. 1 and 4, the width 160w of the third ink drop hole 160 is smaller than the width 140w of the first ink drop hole 140. The width 160w of the third ink drop hole 160 may be substantially the same as the width 150w of the second ink drop hole 150. In some specific examples, the width 160w of the third ink drop hole 160 may be different from the width 150w of the second ink drop hole 150. The third ink drop hole 160 is configured to form an auxiliary electrode, wherein the auxiliary electrode can be connected to the finger electrode. Therefore, as shown in FIG. 4, the third ink drop hole 160 connects the ends 150e of the at least two second ink drop holes 150. In some specific examples, the third ink drop hole 160 may be connected to at least two of the second ink drop holes 150, that is, the connection between the third ink drop hole 160 and the second ink drop hole 150 is not at the end 150e of the second ink drop hole 150. .

5 and FIG. 6 , FIG. 5 is a schematic diagram of a device for performing a screen printing method according to an embodiment of the present invention, and FIG. 6 is a schematic diagram of a screen printing according to an embodiment of the present invention. A top view of the substrate. In the screen printing method of the present embodiment, the doctor blade 170 and the screen 100 of the above embodiment can be provided, and the substrate 180 can be screen-printed by the doctor blade 170 and the screen 100.

Referring again to FIG. 5, the doctor blade 170 has a scraping surface 172, wherein the scraping surface 172 is defined as the contact surface of the doctor blade 170 with the screen 100 during screen printing. The scraping surface 172 is substantially elongated and can be regarded as a line. The scraping surface 172 has a scraping surface direction 172e, wherein the scraping surface direction 172e is a length extending direction of the elongated or linear scraping surface 172. When the printing is performed, the blade 170 is moved along the predetermined moving direction 170m, wherein the moving direction 170m of the blade 170 is parallel to the second direction 132 in which the second ink removing hole 150 extends. In some exemplary examples, the scraping direction 172e of the scraping surface 172 is perpendicular to the moving direction 170m of the scraper 170, and thus the scraping direction 172e is perpendicular to the second direction 132.

The screen printing process uses the doctor blade 170 to scrape the slurry on the screen 100 to form a slurry pattern layer 190 on the substrate 180 via the definition of the ink drop area of the screen 100, as shown in FIG. In some embodiments, the screen printing process is used to fabricate the bus electrodes and finger electrodes of the solar cell. In the example where the solar cell includes an auxiliary electrode, the screen printing process can simultaneously produce the auxiliary electrode. Therefore, referring to FIG. 5 and FIG. 6 simultaneously, the ink drop region of the screen 100 includes a first ink drop hole 140 for defining the shape of the bus electrode 192 of the paste pattern layer 190, and a finger for defining the paste pattern layer 190. A second ink drop hole 150 of the shape of the electrode 194, and a third ink drop hole 160 for defining the shape of the auxiliary electrode 196 of the paste pattern layer 190. Further, the substrate 180 is a substrate of a solar cell.

During the screen printing process, as the blade 170 moves, the slurry on the screen 100 is scraped and falls on the substrate 180 via the first ink drop hole 140, the second ink drop hole 150, and the third ink drop hole 160. On the surface 180a, a paste pattern layer 190 including a bus electrode 192, a finger electrode 194, and an auxiliary electrode 196 is formed on the surface 180a of the substrate 180. Since the screen printing process is used to fabricate the electrodes of the solar cell, the paste pattern layer 190 is a layer of conductive paste on the light-receiving surface of the solar cell.

Since the angle between the first direction 130 in which the first mesh 112 of the screen 100 extends and the second direction 132 in which the second mesh 114 extends is not a right angle, the direction of extension of the first ink drop hole 140 and the third ink drop hole 160 and the first The direction 130 and the second direction 132 are not parallel. Therefore, when the blade 170 moves along the moving direction 170m of the parallel second direction 132 during screen printing, the scraping direction 172e of the scraping surface 172 is not parallel to the first mesh 112. One direction is 130. Thereby, the influence of the first mesh 112 on the flow and the ink drop of the slurry can be reduced, and the smoothness of filling the first ink drop hole 140 and the third ink drop hole 160 can be improved. Therefore, the screen printing method can effectively avoid the defects of the entire row of ink filling defects when the bus electrodes and the auxiliary electrodes are printed, thereby improving the yield of the printing process without the netting screen.

It can be seen from the above embodiments that one of the advantages of the present invention is that one of the warp and the weft of the screen cloth and the ink drop of the finger electrode are parallel and do not overlap, and the other of the warp and the weft and the ink of the finger electrode are inked. The hole is oblique. In the case of screen printing, the moving direction of the blade can be parallel to the direction in which the ink holes of the finger electrodes extend, so that the conventional screen blade can be used without greatly modifying the existing screen printing machine.

It can be seen from the above embodiments that another advantage of the present invention is that the extending direction of the scraping surface of the blade during the screen printing process is also the extending direction of the ink collecting holes of the bus electrode and the auxiliary electrode, and the warp and weft of the mesh cloth. They are not parallel, so it can effectively solve the problem that the traditional net-free screen version is easy to produce uneven charging of the bus electrode and the auxiliary electrode during screen printing, thereby greatly improving the yield of the printing process without the net-screen version.

It can be seen from the above embodiments that another advantage of the present invention is that because the direction of the ink drop of the auxiliary electrode of the screen is not parallel to the warp and weft of the mesh, the warp and weft are less likely to occupy the auxiliary electrode. In the case of the ink drop hole, the influence of the warp and weft on the ink drop of the auxiliary electrode region can be reduced.

While the present invention has been described above by way of example, it is not intended to be construed as a limitation of the scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

Claims (9)

 A screen comprising: a mesh comprising a plurality of first meshes extending in a first direction and a plurality of second meshes extending in a second direction, wherein the first direction and the second direction The angle is not a right angle; and a barrier layer is attached to the mesh and includes a first ink drop hole and a plurality of second ink drop holes, wherein the width of the first ink drop hole is greater than the width of each of the plurality of second ink drop holes, The plurality of second ink drop holes extend in the second direction, and the plurality of second ink drop holes and the plurality of second mesh wires do not overlap, and the first ink drop holes extend in a direction perpendicular to the second direction.    For example, in the screen of the first aspect of the patent application, wherein the acute angle between the first direction and the second direction is 55 degrees to 75 degrees.    For example, in the screen version of claim 2, wherein the acute angle between the first direction and the second direction is 60 degrees to 68 degrees.    The screen of any one of the items 1 to 3, wherein the barrier layer further comprises a third ink drop hole, the third ink drop hole having a width smaller than a width of the first ink drop hole, the third The direction in which the ink drop holes extend is parallel to the first ink drop holes.    The screen of claim 4, wherein the third ink drop hole connects at least two ends of the plurality of second ink drop holes.    The screen of claim 4, wherein the third ink drop hole connects at least two of the plurality of second ink drop holes.    A screen printing method comprising: performing a screen printing process using a doctor blade and a screen of any one of claim 1 to claim 6 to form a slurry on a substrate via the definition of the ink drop area of the screen a pattern layer, wherein the moving direction of the blade is parallel to the second direction when the screen printing process is performed.    The screen printing method of claim 7, wherein the scraping direction of the scraper is perpendicular to the second direction when the screen printing process is performed.    The screen printing method of claim 7 or 8, wherein the substrate is a substrate of a solar cell, and the paste pattern layer is a conductive paste layer on a light receiving surface of the solar cell, the first The ink holes are used to define the shape of one of the conductive paste layers, and the plurality of second ink holes are used to define the shape of the plurality of finger electrodes of the conductive paste layer.