KR20130012076A - Mesh member for screen printing - Google Patents

Abstract

According to the present invention, a screen having a high and high print height and a small variation in print width can be realized even when the width of the printed pattern is reduced (thinned) by using a high viscosity paste, and at the same time, a screen having required and uniform strength. Provided is a printing mesh member. The screen printing mesh member of the present invention is a screen printing mesh member for forming a printing pattern with a photosensitive emulsion, wherein the screen printing mesh member is formed by a rolled metal foil, and the rolled metal foil is formed with a portion corresponding to a printing area of a printing object. It has a part corresponded to the non-printing area of a printing object. In the portion corresponding to the printing area, a plurality of holes having a shape that extends toward the printing object are arranged in a line, and an area where line portions separating adjacent holes are not intersected.

Description

Mesh member for screen printing {MESH MEMBER FOR SCREEN PRINTING}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mesh member used for screen printing. In particular, in printing using a high viscosity paste used for printing surface electrodes of solar cells, the printing height is high even when the width of the printing pattern is made small (thin). The present invention also relates to a mesh member for screen printing for realizing small print width variations.

Screen printing is also used for the production of electronic parts such as a multilayer chip capacitor and the formation of current collecting main electrodes (bus bars) and collecting grid electrodes (finger electrodes), which are surface electrodes of solar cells. As a printing plate (screen plate) used for screen printing, the mesh member formed by squeezing the fine wire which consists of metal or resin (polyester) is used. In addition, a mesh fabric formed by squeezing a polyester thin wire (hereinafter sometimes referred to as a "metal mesh fabric") may be referred to as a mesh fabric formed by woven stainless steel fine wire (hereinafter referred to as a "polyester mesh fabric"). ) Is also widely used.

When creating a combination mask, first, a metal mesh fabric is bonded to the polyester mesh fabric attached to the aluminum mold, and after drying, the polyester mesh fabric of the part which overlapped with the metal mesh fabric is cut | disconnected. Then, a combination mask is produced by apply | coating a photosensitive emulsion and exposing and developing a desired printing pattern on a metal mesh fabric. When the mesh fabric formed by squeezing fine wires has the same thickness, the higher the opening ratio (total area ratio of the mesh openings 2 shown in Fig. 1) of the mesh fabric, the larger the amount of paste to be transmitted. Metal mesh fabrics having an aperture ratio of about 50 to 60% are used for printing the surface electrodes of solar cells.

In order to reduce the size of electronic components and improve the power generation efficiency of solar cells, efforts have been made to make the width of electrodes printed by screen printing thin and high. Since the resistance value of the electrode depends on the cross-sectional area, in order to reduce the size of the electronic component and increase the light receiving area of the solar cell to increase power generation efficiency, the electrode is made thin and high, and the cross-sectional area is made as large as possible, so that the resistance value of the electrode is increased. It is necessary to prevent it from getting high. However, when printing using a metal mesh fabric, there is a problem that mesh marks are likely to remain, and variations occur easily in high and low printing levels. In addition, after printing (after the squeegee for printing passes), the paste may remain at the intersection of the thin lines of the mesh fabric of the printing plate, resulting in a decrease in the printing (electrode) height. Therefore, in the case where the print pattern width is made smaller, print blurring is likely to occur, and a portion having a low electrode height may exist. In such a case, the desired electric resistance value is not obtained.

1 is an enlarged explanatory view of a part of a printing plate which is usually used for screen printing. In FIG. 1, the fine wire 1 which consists of metal and polyester is squeezed, and the mesh member (mesh fabric) which has the opening part 2 is attached to the screen frame (not shown). Thereafter, the photosensitive emulsion (resin) 4 is applied to the entire surface, covered with a mask, and the photosensitive emulsion 4 is cured by exposure to only the unprinted portion. And the printing plate 5 is produced by removing the photosensitive oil agent 4 of the part to be printed.

In screen printing, as shown in Fig. 2A, the paste 7 is filled into the opening 2 of the print pattern portion 3 (see Fig. 1) by moving the squeegee 6, The paste 7 is attached to the printed object 8. After the squeegee 6 passes, the printing plate 5 (see FIG. 1) is spaced apart from the printing object 8 by the tension (tension) of the printing plate, but the paste 7 remains on the printing object 8. Thereafter, three patterns of the printing pattern portion from which the photosensitive emulsion 4 has been removed are printed. The paste 7 immediately after printing is thick in the part corresponding to the opening part 2, and the part corresponding to the thin wire 1 is thin (FIG. 2 (b)). Thereafter, the paste 7 is flattened (leveled) due to the viscosity and surface tension of the paste 7 (Fig. 2 (c)). At this time, the paste 7 spreads beyond the opening 2 of the printing plate 5. The spreading of this paste is indicated by reference numeral 7a in FIG. 2C and is called spreading of printing.

In addition, the printing film thickness (thickness d1 of the paste 7 applied to the printing object 8) is determined by the thickness of the printing plate 5 and the opening ratio (the total area ratio of the opening 2) of the mesh member. When the print areas are the same, it is known that the following relationship is established.

Print Film Thickness (占 퐉) = Thickness of Printing Plate (占 퐉) 占 Opening Rate (%)

When a mesh member having no unevenness on the surface is used, it is difficult to leave mesh marks, and it is expected that the height of printing can be reduced. As a method of manufacturing the mesh member with no unevenness | corrugation on the surface, the method of depositing nickel etc. in mesh shape by the electroforming method is proposed (for example, patent document 1, 2). However, it is known that the variation in strength occurs in the metal foil produced by the electroforming method, and there is a fear that the variation in strength also occurs in the mesh member produced by the electroforming method. In addition, although it is also possible to produce a mesh member by punching into an electrolytic foil such as nickel by etching or the like, there is a concern that a variation in strength may occur as in the mesh member by the electroforming method.

Japanese Patent No. 3516882 Japanese Patent No. 2847746

The present invention has been made in view of such a situation, and the printing height is high even when the width of the printing pattern is reduced (thinned) by using a high viscosity paste such as a conductive silver paste used for printing the surface electrode of the solar cell. It is also an object of the present invention to provide a mesh member for screen printing that can realize printing with a small variation in print width and has a necessary and uniform strength.

The screen printing mesh member which could solve the said subject is a screen printing mesh member for forming a printing pattern with the photosensitive emulsion, The said screen printing mesh member is formed of the rolled metal foil, The said rolled metal foil is a thing of a printing object A plurality of holes having a portion corresponding to the print area and a portion corresponding to the non-print area of the print object, and having a shape widening toward the print object are arranged in a line and adjacent to the print area. The point is provided that an area where line portions separating the holes do not intersect is provided.

In the mesh member for screen printing of the present invention, the breaking load (N) when a tensile test is performed at a tensile speed of 10 mm / minute on a test piece having a width of 15 mm and a gage distance of 100 mm cut out from a portion corresponding to the printing area. And the tensile strength converted into 1 cm width of the test piece is 20 N / cm or more.

The mesh member for screen printing of this invention contains that a hole is not formed in the part corresponded to a non-printing area. In the mesh member for screen printing according to the present invention, a plurality of holes are formed in a portion corresponding to the non-printed region, and the aperture ratio of the hole in the portion corresponding to the non-printed region corresponds to the printed region. It also includes smaller than the opening ratio of the hole in the.

It is preferable that the mesh member for screen printing of this invention is 5 micrometers or more and 30 micrometers or less in thickness. In addition, it is preferable that the screen printing mesh member of the present invention is round at least a part of the contours of the boundary corresponding to the print area and the portion corresponding to the non-print area. Moreover, it is preferable that the mesh member for screen printing of this invention is flat at least one side of the said line part.

Although the rolled metal foil used as the raw material of the mesh member for screen printing of this invention is not specifically limited, Any of stainless steel, titanium or a titanium alloy, nickel or a nickel alloy, copper or a copper alloy, and an aluminum alloy is mentioned.

According to the screen printing mesh member of the present invention, even when a high viscosity paste is used, printing with a high printing height and a small variation in printing width can be realized, and a screen printing mesh member having a necessary and uniform strength can be realized. have. The mesh member for screen printing of the present invention is extremely useful for the production of electronic components and for the formation of a main electrode (booth bar) for collectors and grid electrodes (finger electrodes) for surface electrodes of solar cells.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an enlarged explanatory view of a portion of a printing plate normally used for screen printing.
(A), (b), (c) is a figure for demonstrating the filling state of the paste in screen printing in the prior art.
It is a figure explaining the situation in which the presence of the intersection part of the line part which comprises a mesh member affects the number of disconnections.
FIG. 4 is a graph showing the relationship between the number of points and the number of disconnections in a portion where the line width B shown in FIG. 3 is 50% or more of the print width A (the line width is 50% or more and the print width or more).
It is an enlarged view for demonstrating the opening shape of the hole of the conventional mesh member.
It is explanatory drawing which shows an example of the form of the mesh member of this invention.
It is explanatory drawing which shows the other example of the form of the mesh member of this invention.
It is explanatory drawing which shows the other example of the form of the mesh member of this invention.
9 is an explanatory diagram showing another example of the shape of the mesh member of the present invention.
It is explanatory drawing which shows an example of the form of the mesh member of a comparative product.
(A) is explanatory drawing which shows the other example of the form of the mesh member of this invention, (b) is a figure which shows the state which apply | coated the photosensitive oil agent to the mesh member of (a).
12 (a) and 12 (b) are explanatory diagrams showing an example of the opening shape of the hole in the mesh member of the present invention.
(A), (b), (c), (d) is explanatory drawing which shows the various examples of the opening shape of the hole in the mesh member of this invention.
It is explanatory drawing which shows the other example of the form of the mesh member of this invention.
(A), (b), (c) is a figure for demonstrating the filling state of the paste in screen printing at the time of using the mesh member of this invention.
FIG. 16 is a photograph-based reference diagram showing an enlarged shape of a part of the mesh member obtained in the first embodiment.
FIG. 17 is a photograph-based reference diagram showing an enlarged shape of a part of the mesh member obtained in the second embodiment. FIG.

The present inventors observed the discharge state of the high-viscosity paste using the mesh member punched by the rolled metal foil (rolled metal foil mesh member), and the mesh member comprised from the mesh fabric which woven the stainless fine wire. As a result, according to the rolled metal foil mesh member, it turned out that the discharge situation of a paste is uniform compared with the mesh member comprised by the mesh fabric. In addition, although the residual of the paste was observed in the opening of the mesh fabric, the paste did not remain in the hole (opening) of the rolled metal foil mesh member. As described above, according to the rolled metal foil mesh member, since the ejection of the paste is uniform and the paste does not remain in the opening, printing with a low level difference can be performed. However, when the rolled metal foil mesh member is used, print blurring may occur when the width of the print pattern is narrow.

MEANS TO SOLVE THE PROBLEM In order to analyze the cause which this phenomenon generate | occur | produces, in order to analyze the cause which this phenomenon generate | occur | produces, in the stainless steel rolled foil (made by Toyo Seihaku Co., Ltd., standard SUS304-H) of 21 micrometers, the mesh number 250 or 320 (piece / inch), and the aperture ratio 50- A mesh member was produced by punching out to 62%, 22.5 degrees or 57.5 degrees bias. Using these mesh members, the present inventors produced the printing plate whose width (print pattern width) of a printing pattern part is 40 micrometers, 60 micrometers, 80 micrometers, and 100 micrometers, respectively. In addition, in this invention, "bias" means the angle which the direction of the line part 1a (refer FIG. 5) of a mesh member, and the printing direction (left-right direction of FIG. 14) make.

The present inventors carried out a printing test using these printing plates and the silver paste for solar cells, and measured the number of print blur points (number of disconnection lines) per 1 cm of printing length after printing. As a result of the measurement, disconnection hardly occurred when the printed pattern width was 100 µm or 80 µm. However, as the printed pattern width became thinner to 60 µm and 40 µm, the number of disconnections increased, and when the printed pattern width was 40 µm, the number of disconnections became maximum.

Therefore, the present inventors observed a printing plate with a microscope (Model VHX-2000, manufactured by Guyens Co., Ltd.), and analyzed the factors affecting the number of disconnection. As a result of the analysis, when the intersection of the line portions constituting the mesh member is present in the print pattern portion, 50% or more of the print pattern width (print width) is blocked by the line portion, and the number of locations where the length of the blocked portion is equal to or larger than the print pattern width. It has been found that there is a positive correlation between and the number of locations (disconnections) of print blur.

3 is a view for explaining a situation in which the presence of the intersection portion 9 of the line portion 1a constituting the mesh member affects the number of disconnections. In Fig. 3, A is the print pattern width (print width), B is the width blocked by the line portion 1a, and C is the width of B (the line width: the line width blocked by the line portion 1a) is 50% or more of A. Each length is shown. 4 shows the relationship between the number of points and the number of disconnections in a portion where the line width B is at least 50% of the print width A, and the line width B is at least the print width A (however, the print pattern width is 100 µm or 80 µm). There was no disconnection, so not shown).

From these results, it was considered as follows. That is, the location where the line part 1a blocks 50% or more of the print pattern width A was the location where the part (intersection part 9) which the line part 1a of a mesh member cross | intersects exists in the print pattern A. As shown in FIG. As a result, it is expected that if the crossing portion 9 of the mesh portion 1a of the mesh member is thin, it is possible to realize printing without printing blur. However, when the intersection 9 of the line part 1a is made small significantly, intensity | strength will fall and there exists a possibility that it may be broken at the time of printing plate manufacture, or printing. Accordingly, the present inventors further examined a method for removing the influence of the intersection portion 9 of the line portion 1a.

In the conventional mesh member, as shown in Fig. 5, the line portion 1a is formed in a lattice state and has an intersection portion 9. However, such a problem occurs in such a mesh member. Therefore, the inventors of the present invention do not have the intersection 9 of the line portion 1a in the region for the print pattern (the portion corresponding to the printing region of the object to be printed: hereinafter sometimes referred to simply as the “printing region equivalent portion”). It was overlaid on the mesh member.

It is explanatory drawing which shows an example of the form of the mesh member of this invention. In the mesh member of the present invention, as shown in Fig. 6, by arranging the holes 2 in the print area in a row, the ejection property of the paste is good by eliminating the portions where the line portions 1a intersect at the corresponding areas of the print area. The mesh member can be realized. Since the discharge of the paste becomes uniform and good, the print height is high (no print blur) even when the print pattern width is thinned, there is no elevation difference, and the variation in print width is also reduced. In addition, only a substantial portion of the printed area is punched out, and a perforated non-printed area (part corresponding to the non-printed area of the object to be printed) is not punched, or a portion of the non-printed area corresponding to the non-printed area corresponds to a lower aperture ratio than that of the printed area. By punching in, the strength as a mesh member can be maintained. Fig. 7 shows a plan view of an example of such a mesh member (holes in the non-printed area equivalent portion 12 are not shown). In addition, in at least one portion of the print area equivalent portion 11, when the holes 2 are arranged in a line as described above, the effects of the present invention can be obtained. FIG. 8 shows a plan view of an example of a mesh member in which only holes are arranged in a line in a portion of the print area equivalent portion 11 (right side in the drawing) so that no intersection portion of the line portion is formed (non-print area equivalent portion). Holes 12 are not shown]. In FIG. 8, the intersection part of a line part is formed in the other part (left side of drawing) of the printing area correspondence part 11. As shown in FIG. In addition, in the present invention, "arranged in a row" means a state in which the holes 2 are arranged side by side in the same direction as shown in Figs.

In order to confirm the effectiveness of the mesh member (that is, the mesh member which does not have the intersection part 9 of the line part 1a) of this invention, the stainless steel rolled foil of 21 micrometers in thickness (made by Toyo Seihaku Co., Ltd., specification SUS304-H) ), The hole 2 in the printing area was processed by etching from one side so that the holes 2 of the printing area were square and in a line, thereby producing a rolled metal foil mesh member. The line width of the rolled metal foil mesh member is 15 mu m, the opening width is 85 mu m, and the number of meshes is 250 (pieces / inch). The rolled metal foil mesh member (invention) of this invention is shown as a top view in FIG. 9 (the hole of a non-printed area is not shown).

A plurality of rectangular holes 2 are arranged in a printing area (a printing area with a wide printing pattern width and a narrow printing pattern width) Rolled metal foil mesh was prepared. The rolled metal foil mesh member of this comparative product is shown as a top view in FIG. 10 (the hole of the non-printed area is not shown).

In addition, the bias of the mesh member (FIG. 9) of this invention which does not have the intersection part of a front line is 0 degree, and the bias of the comparative product (FIG. 10) with an intersection part 9 is 22.5 degree. Using these rolled metal foil mesh members, the printing plate of 40 micrometers of printing patterns was produced, and the printing test was done using the silver paste for solar cells. Each of the three printed electrodes was observed with a microscope (Gene: Model VHK-2000), so that the number of print blurs (number of disconnections) per 1 cm of electrode length was measured. The results are shown in Table 1.

From this result, it can consider as follows. Since the comparative product has the intersection 9 of the line portion 1a in the printing pattern, the paste does not sufficiently return to the lower side of the line portion of the mesh member at this portion, and print blur occurs. On the other hand, since the mesh member of the invention does not have the intersection portion 9 of the line portion 1a, the paste sufficiently returns to the lower side of the line portion, and print blur does not occur.

When the shape (opening shape) of the hole (opening) 2 in the mesh member is square (FIGS. 6 and 9), the exposure position (that is, the application position of the photosensitive emulsion) is printed when exposing the printing pattern. There exists a possibility that it may shift | deviate from an area | region and a printing pattern may not be formed like a design. In addition, when the printing pattern is shifted from the printing area and enters the non-printing area, the paste is not discharged. Therefore, it is preferable that the hole 2 has an opening width larger than the printed pattern width. Fig. 11 (a) is a plan view of the mesh member, and Fig. 11 (b) is a view showing a state in which the photosensitive member is applied to the mesh member of Fig. 11 (a). In the region not having the intersection portion 9 of the line portion 1a of the portion corresponding to the printing area, if the shape of the hole 2 is rectangular, the strength can be maintained and the printing is performed even if the position where the print pattern is exposed is slightly shifted. The photosensitive oil agent 4 can be apply | coated to an area | region (FIG. 11B), and a printing pattern can be formed.

In order to avoid stress concentration at the time of attaching the mesh member to the aluminum frame or during the pressure applied by the squeegee in printing, in the printing area equivalent portion 11, at the corner of the hole 2 in the area not having the intersection of the line portion. It is preferable to give R shape. FIG. 12A shows the case where the opening shape of the hole 2 is rectangular, and FIG. 12B shows the case where the hole 2 has an R shape. In addition, the opening shape of the hole 2 is not limited to arrange | positioning a square or a rectangle in parallel. For example, the parallelogram 2 (FIG. 13A) and the trapezoid 2 of FIG. 13C may be arranged in a line, and the rectangular hole 2 may be inclined. May be arranged in a line (FIG. 13B), or may be arranged by bending a rectangle (FIG. 13D), and various shapes may be employed. What is necessary is just to select these shapes in consideration of the shape, width, etc. of a printing pattern.

As shown in FIG. 14, at least among the contours of the boundary between the portion of the rolled metal foil (printed region equivalent portion 11) corresponding to the printing region and the portion of the rolled metal foil (nonprinted region equivalent portion) corresponding to the non-printed region. When a part is formed round, the stress concentration at the time of strapping a mesh can be reduced and the mesh member which is hard to break can be obtained. In particular, even when the thickness of the mesh member is thin (about 20 µm or less), the opening ratio is high, and the mesh is strapped with a high tension, it can be expected that the fracture can be prevented.

In addition, the boundary D between the print area equivalent part 11 and the non-print area equivalent part 12 is the opening part 2 of the print area correspondence part 11, as shown to FIG. 12 (a), (b). Is set based on the end of This boundary D becomes a reference | standard at the time of calculating each opening ratio of the printing area correspondence part 11 and the nonprinting area correspondence part 12. As shown in FIG.

The mesh member of the present invention is constructed from the viewpoint of improving the strength while increasing the aperture ratio. The rolled metal foil has a portion (non-printing region equivalent portion) corresponding to the non-printing region of the printing object in addition to the portion (printing region equivalent portion) corresponding to the printing region of the printing object, but the mesh member of the present invention is equivalent to the non-printing region. It includes the form in which a hole is not opened in the part (that is, the opening ratio is 0%). In addition, although the hole is open in the nonprinting area | region equivalence part, the mesh member of this invention also includes the form whose opening ratio of the hole in a nonprinting area equivalency part is smaller than the opening ratio of the hole in the printing area equivalence part, etc. are also included.

When a hole is not formed in the non-printed region equivalent part of the rolled metal foil, the strength is sufficient. However, in such a case, since adhesiveness with a rolled metal foil becomes low depending on the kind of photosensitive oil agent, peeling in the middle of printing repeatedly is feared. Therefore, it is good to set the opening ratio of the substantial portion of the non-printed area in consideration of the adhesiveness (and the kind of the rolled metal foil affecting the adhesiveness) of the photosensitive oil agent.

In addition, in order to prevent the paste from remaining inside the mesh member and to improve the ejectability of the paste having a high viscosity, the shape of the hole 2 in the thickness direction of the rolled metal foil is widened toward the printing object 8. It is preferable if it is a shape (refer FIG. 15 (a)). In addition, the opening ratio of the mesh member when the hole 2 is formed in the shape which spreads toward the printing object 8 is made into the average value of the opening ratio of the squeeze surface side and the printing object surface side.

If there is a part with low strength in the mesh member, a crack may occur due to the pressure of the squeegee at the time of attaching the mesh to the aluminum frame or at the time of printing, and the whole mesh may be broken. The part with the lowest strength among mesh members is the part with the highest opening ratio. Therefore, a tensile test is performed at a tensile rate of 10 mm / min for a test piece having a width of 15 mm and a gage distance of 100 mm, cut out so that the portion having the highest opening ratio among the substantial portions of the printed area of the mesh member becomes the center portion of the gage distance. It is preferable that the tensile strength when converting the breaking load (N) at the time of performing the test into 1 cm width of the test piece is 20 N / cm or more.

The test to confirm whether the presence or absence of the intersection part of the line part of a printing area affects tensile strength was done. A stainless steel rolled foil having a thickness of 21 μm (manufactured by Toyo Seihaku Co., Ltd., standard SUS304H) is punched only in a printing area, and a mesh member (invention product) having no intersection part of the line in the printing area and a mesh member having an intersection part ( Comparative product) was produced. The basic shape of each mesh member is the same as that of FIGS. 9 and 10, respectively. In addition, the width | variety of a line part is 50 micrometers, the opening width is 150 micrometers, and the number of meshes is 125 (piece / inch). In addition, the bias of the mesh member without the intersection part of the front part is 0 degree, and the bias of the mesh member with the intersection part is 22.5 degree.

The test piece of width 15mm and gage distance 100mm was cut out from each mesh member so that a printing area | region (opening) may become a center part, and a tension test was carried out at a tensile speed of 10 mm / min using a tensile tester (made by Orientec Co., Ltd.). Was carried out. The tensile strength per unit width is obtained by converting the fracture load (N) at the time of tensile test to the width of 1 cm of the test piece. The results are shown in Table 2. Thereby, even when there is no intersection part of a ship part (invention article), it turns out that it has the same tensile strength as the case where there exists an intersection part of a ship part (comparative product).

The higher the opening ratio of the mesh member, the larger the permeation amount of the paste per the same area. Therefore, in screen printing using a rolled metal foil mesh and a high viscosity paste, it is preferable that the opening ratio of the area | region for a paste to permeate is high. When printing using the comparatively high viscosity paste in electroconductive silver paste, it is preferable that an opening ratio is 50% or more, ideally 70% or more. However, since increasing the opening ratio may lead to a decrease in strength of the mesh member, it is preferable that the opening ratio when the thickness is 5 μm is about 50%, and the opening ratio when the thickness is 30 μm is about 90%.

In addition, when the width of the printed pattern is small, when the number of meshes is small (that is, the pitch of the front portion of the mesh member is large), it is necessary to increase the width of the front portion in order to secure the required strength. Therefore, when the printed pattern width is thin (for example, less than 100 µm), it is preferable to increase the number of meshes, that is, to reduce the pitch of the front portion of the mesh member. From this point of view, the mesh number is preferably 125 (pieces / inch) or more. However, when the number of meshes is excessively large, the opening width becomes small, and high viscosity paste becomes difficult to permeate (discharge). Therefore, the mesh number is preferably 420 (pieces / inch) or less. When using a paste having a thinner print pattern width (e.g., less than 60 mu m) and having a high viscosity, the mesh number is 210 (pieces / inch) or more and 320 (pieces / inch) or less is suitable.

In the case where the same thickness photosensitive emulsion is used, the thicker the mesh member is, the thicker the printing can be. However, depending on the paste used for printing, if the thickness of the mesh member is too thick, a high level difference in printing height is likely to occur. When such a situation is anticipated, in order to reduce the height difference, it is preferable that the thickness (namely, thickness of the rolled metal foil) of a mesh member is 30 micrometers or less. As the thickness of the mesh member becomes thinner, printing with less height difference becomes possible, but rolling metal foil whose thickness is less than 5 micrometers is difficult to obtain, and securing of strength is also difficult. Therefore, it is preferable that the thickness of a mesh member is 5 micrometers or more. From the viewpoint of securing the strength, the thickness is more preferably 10 µm or more.

The mesh member of the present invention is produced by forming a plurality of holes as described above in a rolled metal foil. At least one surface constituting the line portion of such a mesh member is flat, and, for example, as shown in FIG. 15 (a), the squeegee 6 moves more smoothly than a mesh woven fine wire having irregularities on its surface. As it becomes, it is preferable. In addition, according to such a mesh member, as shown in FIG. 15B, the paste 7 is easily stretched uniformly, and at the same time, a relatively thick print film thickness as shown in FIG. 15C. The pattern of d2 can be printed. In addition, when the metal mesh has such a flat surface at the time of manufacturing a combination mask (mask in which the periphery is a resin mesh and the center is a metal mesh), there is an advantage that adhesion with the resin mesh is facilitated. 15A also shows a state in which the hole 2 is formed to be widened toward the printing surface side (the printing object 8 side).

Although the mesh member of this invention can be manufactured by punching a rolled metal foil by etching, laser processing, and shot blasting, the method by an etching is optimal from an opening precision and an opening speed. In addition, when punching by etching, when punching by etching from both surfaces, there exists a possibility that a paste may stay at the time of screen printing by the convex part formed in a part of hole. Therefore, punching work by etching from one side is good. As a result, the shape (outer shape) of the hole 2 becomes a shape which spreads toward the other side from one side of the thickness direction of a rolled metal foil. Thus, by forming the hole of the shape which spreads toward a printing object, the situation where a paste stays can also be avoided.

The procedure of manufacturing the mesh member of this invention is as follows by forming many holes in the rolled metal foil by the punching process by etching. First, the photosensitive resist can be applied to the rolled metal foil in a state where the rolled metal foil is adhered to and adhered to a fixed plate having a flat surface such as glass, or the roll is wound around the rolled metal foil, that is, the rolled metal foil is adhered without wrinkles. Apply thinly. Thereafter, the pattern of the opening is formed in the rolled metal foil by exposing and developing the pattern of the opening of the mesh drawn in the mask.

The procedure for manufacturing the mesh member which has a nonprinting area | region equivalence part with many holes opened, and whose aperture ratio of the hole in a nonprinting area equivalency part is smaller than the aperture ratio of the hole in a printing area correspondence part is as follows. First, after apply | coating a photosensitive resist to a rolled metal foil, the mask which draws the opening pattern of the non-printed area correspondence part is arrange | positioned on the mask on which the opening pattern of the print area correspondence part was drawn. Thereafter, by exposing and developing and subsequently etching, a mesh member having a portion having a high aperture ratio and a portion having a low portion can be manufactured in a relatively simple procedure.

In the case where the printing area is set in accordance with the printing pattern to be exposed and punched out, when the mesh member is attached to the aluminum frame, the mesh member may be stretched to shift the position of the printing area from the printing pattern. Therefore, when exposing a print pattern, there exists a possibility that the exposed print pattern may be excluded from a printing area. In that case, part of the printing pattern enters the non-printing area and paste is not ejected, resulting in print blur or variation in print width. Therefore, if the position of the printing area to be punched is biased in advance at the center, the mesh member is elongated when attached to the aluminum frame, so that the position of the printing pattern can be easily matched.

A test was conducted to confirm the validity of the configuration. Punching is performed by etching from one side to a stainless steel rolled foil having a thickness of 21 μm (manufactured by Toyo Seihaku Co., Ltd., standard SUS304-H) so that the outermost side of the printing area has a scaling factor of 0.9992 (100 μm inner side) with respect to the printing pattern. , The rolled metal foil mesh of the present invention was produced. The printing area with a high aperture ratio is shaped to match the shape of the surface electrode pattern of the solar cell, and the portion for exposing and developing the printing pattern of the finger electrode is 500 µm in width. Using this mesh member, a printing plate was produced. For comparison, a mesh member punched out without scale was produced in a state in which the printing pattern was matched. About these mesh members, the magnitude | size of the position shift of the printing pattern from the center of a printing area | region was measured with the microscope (made by Giens Co., Ltd., model VHX-2000). Table 3 shows the results. Thereby, according to the mesh member of this invention, it was confirmed that the position shift was few.

The raw material of the rolled metal foil may be foil-shaped with titanium or a titanium alloy, nickel or a nickel alloy, copper or a copper alloy, an aluminum alloy or the like in addition to stainless steel. For example, stainless steel is SUS304-H or the like, titanium alloy is JISH4600 80 kinds, nickel alloy is JISCS2520 (1986) NCHRW1, copper alloy is JISH3130 C1720R-H, aluminum alloy is JISH4000 5052 or the like. Moreover, such rolled metal foil is generally marketed and can be easily obtained.

(Example)

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples are not of the nature of limiting the present invention, and may be appropriately changed and carried out in a range suitable for the purpose of the preceding and the latter, and they are all included in the technical scope of the present invention.

[First Embodiment]

A commercially available stainless steel rolled foil (made by Toyo Seihaku Co., Ltd .: standard SUS304H) having a thickness of 21 µm was punched out from one side by etching to produce a rolled metal foil mesh. The area with high aperture ratio is a shape matched with the shape of the surface electrode pattern of a solar cell. The part which exposes and develops the printing pattern of a finger electrode is 500 micrometers in width, and 152 mm in length. The part which exposes and develops the pattern of a bus bar is 2.4 mm in width and 152 mm in length. Moreover, the hole is formed in the shape which opens an opening toward a printing surface side. The pitch on the printing surface side of the portion having a high aperture ratio (printing region equivalent portion) is 80 µm, and the number of meshes is 320 (pieces / inch). Among the portions having a high aperture ratio (printed area equivalent portions), the aperture ratio of the portion exposing and developing the print pattern of the finger electrode is 78%, the aperture ratio of the portion exposing and developing the pattern of the busbar is 52%, and the aperture ratio is low. The opening ratio of the portion (non-printed area equivalent) is 20%. Among these, portions where the line portions intersect are not present at portions where the print pattern of the finger electrode is exposed and developed. The opening shape of the hole of the part with a high opening ratio has given the R shape to the corner. The enlarged shape of a part of the obtained mesh member is shown in Fig. 16 (microscope photograph for drawing).

This mesh member was bonded with the polyester thin wire mesh, and after apply | coating a photosensitive emulsion, the printing pattern of the finger electrode width of 40 micrometers and busbar width of 2 mm was exposed and developed, and the printing plate was produced. Using the produced printing plate, printing was performed using a conductive silver paste ("RAFS" manufactured by Toyo Ink Co., Ltd.), and the printing height was measured by a laser microscope (model VK-9700 manufactured by Giens Co., Ltd.). As a result, it was confirmed that there was no print blur and printing with an average height of 18 µm, an elevation difference of 9 µm, and a width variation of 4 µm was possible.

Further, from the obtained mesh member, a width of 15 mm and a gauge length of 100 mm such that the portions (portions where the holes are arranged in a row) for exposing and developing the print pattern of the finger electrode having the highest aperture ratio among the portions corresponding to the print region are located at the center of the gauge length, Mm was cut out. About this test piece, the tensile strength which converted the breaking load (N) at the time of the tensile test at a tensile velocity of 10 mm / min per 1 cm of width of the test piece was 29 N / cm.

[Second Embodiment]

A commercially available stainless steel rolled foil (made by Toyo Seihaku Co., Ltd .: standard SUS304H) having a thickness of 21 µm was punched out from one side by etching to produce a rolled metal foil mesh. The area with a high aperture ratio is shaped to match the shape of the surface electrode pattern of the solar cell, and the dimensions of the part exposing and developing the printed pattern of the finger electrode are 400 μm wide, 152 mm in length, and the part exposing and developing the pattern of the bus bar. The dimension of is 2.4 mm in width and 152 mm in length. The outer shape of the hole is a shape in which the opening is widened toward the printing surface side. The pitch on the printing surface side of the portion having a high aperture ratio (printing region equivalent portion) is 100 µm and the number of meshes is 250 (pieces / inch). Among the portions having a high aperture ratio (corresponding to the print area), the aperture ratio of the portion for exposing / developing the print pattern of the finger electrode is 64%, the aperture ratio of the portion for exposing / developing the pattern of the busbar is 51% (Corresponding to the non-printing area) is 20%. Of these, portions where the line portions intersect are not present in portions where the print pattern of the finger electrode is exposed and developed, and portions where the portions cross each other. The opening shape of the hole of the part with a high opening ratio has given the R shape to the corner. The enlarged shape of a part of the obtained mesh member is shown in Fig. 17 (microscope photograph for drawing).

This mesh member was bonded with the polyester thin wire mesh, and after apply | coating a photosensitive emulsion, the printing pattern of the finger electrode width of 60 micrometers and busbar width of 2 mm was exposed and developed, and the printing plate was produced. Using the obtained printing plate, printing was performed using a conductive silver paste ("RAFS" manufactured by Toyo Ink Manufacturing Co., Ltd.), and the printing height was measured with a laser microscope (Model VK-9700, manufactured by Kyoritsu Co., Ltd.). As a result, it was confirmed that printing was possible without printing blur, and the average height was 26 µm, the elevation difference was 6 µm, and the variation in width was 5 µm.

In addition, the width of the obtained mesh member is such that the portion of the print area equivalent portion that exposes and develops the print pattern of the finger electrode having the highest aperture ratio among the print area equivalent portions (the portion in which the holes are arranged in line) becomes the center portion of the mark distance. The test piece of 15 mm and the gage distance 100 mm was cut out. This test piece was subjected to a tensile test at a tensile rate of 10 mm / minute. The tensile strength which converted breaking load N at this time per width of 1 cm of test piece was 43 N / cm.

As mentioned above, although embodiment and Example of this invention were described, this invention is not limited to embodiment mentioned above, It can change and implement variously in the range as described in a claim. This application is based on the JP Patent application (Japanese Patent Application No. 2010-137720) of an application on June 16, 2010, The content is taken in here as a reference.

1: thin wire
1a: line part
2: hole (opening)
3: printing pattern part
4: photosensitive emulsion
5: printing plate
6: squeegee
7: paste
7a: smeared
8: printing object
9: intersection

Claims (8)

It is a mesh member for screen printing for forming a printing pattern with a photosensitive emulsion,
The mesh member for screen printing is formed by rolled metal foil,
The rolled metal foil has a portion corresponding to a print area of the print object and a portion corresponding to a non-print area of the print object,
In a portion corresponding to the printing area, a plurality of holes having a shape widening toward a printing object are arranged in a line, and an area where line portions separating adjacent holes are not intersected is provided. Printable mesh member. The breaking load N when the tensile test is performed at a tensile speed of 10 mm / min with respect to a test piece having a width of 15 mm and a gage distance of 100 mm cut out from a portion corresponding to the printing area, according to claim 1. The mesh member for screen printings whose tensile strength converted into 1 cm of width of a test piece is 20 N / cm or more. The mesh member for screen printing according to claim 1 or 2, wherein no hole is formed in a portion corresponding to the non-printed region. The part corresponding to the said nonprinting area | region is formed with many holes, The opening ratio of the hole in the part corresponded to the said nonprinting area | region is a part corresponding to the said printing area | region. The mesh member for screen printing smaller than the aperture ratio of the hole in a hole. The mesh member for screen printing as described in any one of Claims 1-4 whose thickness is 5 micrometers or more and 30 micrometers or less. The mesh member for screen printing according to any one of claims 1 to 5, wherein at least a part of a contour of a boundary corresponding to the print area and a portion corresponding to the non-print area is rounded. The mesh member for screen printing according to any one of claims 1 to 6, wherein at least one side of the line portion is flat. The mesh member for screen printing according to any one of claims 1 to 7, wherein the rolled metal foil is made of any one of stainless steel, titanium or titanium alloy, nickel or nickel alloy, copper or copper alloy, and aluminum alloy.

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