Screen mesh, screen mask, method for producing conductive pattern, and method for producing conductive substrate

Abstract

To provide a screen mesh that enables printing with reduced thickness irregularity.SOLUTION: A screen mesh 10 is used for printing conductive ink. In plan view, the screen mesh 10 comprises a portion having a plurality of unit shapes 100 combined. Each unit shape 100 is a closed shape constituted at least in part by a curved line. The plurality of unit shapes 100 are each constituted by one or more filamentous bodies. In plan view, in at least one direction, adjacent ones of the plurality of unit shapes 100 are either in contact with one another or overlapping one another.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a screen mesh, a screen mask, a method for manufacturing a conductive pattern, and a method for manufacturing a conductive substrate. [Background technology]

[0002] Screen printing has a variety of uses, including circuit formation.

[0003] Patent Document 1 discloses a mask for printing liquid ceramics. The mask described in Patent Document 1 has an opening area of ​​1 mm, which is larger than the diameter of solid particles generated during printing of liquid ceramics. 2 Furthermore, the tangent of the straight line or curve that defines the opening is inclined at an angle relative to a direction perpendicular to the moving direction of the squeegee. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-014323 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the mask disclosed in Patent Document 1 was not suitable for printing conductive ink to obtain a conductive pattern. When attempting to obtain a conductive pattern by printing conductive ink, it is particularly important that the thickness variation is small.

[0006] The present invention provides a screen mesh that enables printing with minimal thickness variation. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided the following methods for manufacturing a screen mesh, a screen mask, a conductive pattern, and a conductive substrate.

[0008] 1. A screen mesh for printing conductive ink, The structure includes a portion having a structure in which a plurality of closed unit shapes, at least a portion of which is made up of curves, are combined in a plan view, Each of the plurality of unit shapes is composed of one or more filaments, In a plan view, adjacent unit shapes among the plurality of unit shapes are in contact with or overlap each other in at least one direction. Screen mesh. 2. In the screen mesh described in 1., Each of the plurality of unit shapes is substantially a circle or an ellipse. Screen mesh. 3. In the screen mesh described in 2., Each of the plurality of unit shapes is substantially circular. Screen mesh. 4. In the screen mesh described in 2., Each of the plurality of unit shapes is substantially elliptical. Screen mesh. 5. The screen mesh according to any one of 1. to 4., the plurality of unit shapes include a first group consisting of two or more unit shapes from the plurality of unit shapes, and a second group consisting of two or more other unit shapes from the plurality of unit shapes; In each of the first group and the second group, adjacent unit shapes are in contact with each other in at least one direction in a plan view; The first group and the second group overlap in a plan view. Screen mesh. 6. In the screen mesh described in 5., At least one contact point between the unit shapes belonging to the first group and at least one contact point between the unit shapes belonging to the second group overlap in plan view. Screen mesh. 7. The screen mesh according to 5. or 6., an average of diameters of circumscribing circles of the two or more unit shapes constituting the first group is 0.95 to 1.05 times the average of diameters of circumscribing circles of the two or more unit shapes constituting the second group in a plan view; In a plan view, the average circularity of the two or more unit shapes constituting the first group is 0.95 to 1.05 times the average circularity of the two or more unit shapes constituting the second group. Screen mesh. 8. The screen mesh according to any one of 1. to 7., In plan view, the screen mesh has a periodic structure in which periodic units are arranged two-dimensionally, the periodic unit is a square, On the screen mesh, the rectangular slit is moved in the direction of the short side by the length of the short side of the slit, and the opening area through the slit at each slit position is determined, and the maximum value of the determined opening areas is defined as S. max , the minimum value is S min Then, the variability M=(S max -S min ) / (S max +S min ) is 0.8 or less when the orientation of the slit is in the first state and when the orientation of the slit is in the second state, the length of the long side of the slit is the length of one side of the square that is the periodic unit, and the length of the short side of the slit is half the line width of the filament in a plan view, the first state is a state in which a long side of the slit is parallel to any side of the square that is the periodic unit, The second state is a state in which the orientation of the slit is rotated 45° clockwise from the first state. Screen mesh. 9. The screen mesh according to any one of 1. to 7., In plan view, the screen mesh has a periodic structure in which periodic units are arranged two-dimensionally, the periodic unit is a rectangle, On the screen mesh, the rectangular slit is moved in the direction of the short side by the length of the short side of the slit, and the opening area through the slit at each slit position is determined, and the maximum value of the determined opening areas is defined as S. max , the minimum value is S min Then, the variability M=(S max -S min ) / (S max +S min ) is 0.8 or less when the orientation of the slit is in the first state and when the orientation of the slit is in the second state, The length of the long side of the slit is the length of the long side of the rectangle that is the periodic unit, and the length of the short side of the slit is half the line width of the filamentous body in a plan view, the first state is a state in which the long side of the slit is parallel to the long side of the rectangle that is the periodic unit, The second state is a state in which the orientation of the slit is rotated 45° clockwise from the first state. Screen mesh. 10. A screen mesh according to any one of 1. to 9.; a mask layer attached to the screen mesh; Screen mask. 11. A process of performing screen printing using the screen mask described in 10. A method for manufacturing a conductive pattern. 12. Using the screen mask according to 10., a conductive ink containing conductive particles is screen-printed onto a first substrate to form a conductive pattern on the first substrate; transferring the conductive pattern to a second substrate different from the first substrate; and applying pressure to a laminate including the second base material and the conductive pattern. A method for manufacturing a conductive substrate. [Effects of the Invention]

[0009] According to the present invention, a screen mesh that enables printing with minimal thickness variation can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a screen mesh according to a first embodiment. FIG. [Figure 2] 1 is a reference example of a screen mask in a plan view. [Figure 3] FIG. 10 is a diagram for explaining the variability M of the screen mesh. [Figure 4] FIG. 10 is a diagram for explaining the variability M of the screen mesh. [Figure 5] 1 is a diagram showing a first example of the structure of a screen mesh according to a first embodiment. [Figure 6] FIG. 4 is a diagram showing a second example of the structure of the screen mesh according to the first embodiment. [Figure 7] FIG. 1 is a diagram showing the first group and the second group in a distinguished manner. [Figure 8] 10A and 10B are diagrams for explaining an example of a method for manufacturing a screen mesh according to a second example. [Figure 9] 10A and 10B are diagrams for explaining an example of a method for manufacturing a screen mesh according to a second example. [Figure 10] 10A and 10B are diagrams for explaining an example of a method for manufacturing a screen mesh according to a second example. [Figure 11] 10A and 10B are diagrams for explaining an example of a method for manufacturing a screen mesh according to a second example. [Figure 12] FIG. 4 is a diagram showing a third example of the structure of the screen mesh according to the first embodiment. [Figure 13] FIG. 10 is a diagram showing a fourth example of the structure of the screen mesh according to the first embodiment. [Figure 14]2A to 2C are diagrams illustrating the structure of a screen mask according to the first embodiment. [Figure 15] 2A to 2C are diagrams illustrating the structure of a screen mask according to the first embodiment. [Figure 16] 10A and 10B are diagrams illustrating an example of an opening in a mask layer. [Figure 17] 1 is a cross-sectional view illustrating a configuration of a structure including a conductive pattern. [Figure 18] FIG. 10 is a diagram showing the relationship between a screen mesh according to a comparative example and the positions of a plurality of slits in a first state. [Figure 19] 10 is a graph showing the relationship between the slit position and the opening area when the slit is in a first state in a comparative example. [Figure 20] FIG. 10 is a diagram showing the relationship between a screen mesh according to a comparative example and the positions of a plurality of slits in a second state. [Figure 21] 10 is a graph showing the relationship between the slit position and the opening area when the slit is in the second state in a comparative example. [Figure 22] 10 is a graph showing the relationship between the slit position and the opening area when the slit is in a first state in Example 1. [Figure 23] 10 is a graph showing the relationship between the slit position and the opening area when the slit is in a second state in Example 1. [Figure 24] FIG. 6 is a diagram illustrating the flow of a method for producing a conductive substrate according to a second embodiment. [Figure 25] 1A to 1C are diagrams illustrating a method for manufacturing a conductive substrate according to a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are denoted by similar reference numerals, and descriptions thereof will be omitted where appropriate. The x-axis, y-axis, and z-axis directions shown in each drawing are three directions perpendicular to each other, and the xy plane is a plane parallel to the main surface of the screen mesh.

[0012] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5 mass %" means "at least 1 mass % and at most 5 mass %."

[0013] (First embodiment) FIG. 1 is a diagram illustrating a screen mesh 10 according to a first embodiment. FIG. 1 shows the screen mesh 10 in a plan view. The screen mesh 10 according to this embodiment is a screen mesh for printing conductive ink. In a plan view, the screen mesh 10 includes a portion having a structure in which a plurality of unit shapes 100 are combined. Each unit shape 100 is a closed shape, at least a portion of which is curved. Each of the plurality of unit shapes 100 is composed of one or more filaments. In a plan view, adjacent unit shapes 100 among the plurality of unit shapes 100 are in contact with or overlap each other in at least one direction. A plan view refers to a view perpendicular to the main surface of the screen mesh 10.

[0014] It should be noted that there may be multiple shapes that can be interpreted as unit shapes 100 for the same screen mesh 10, but the preferred forms described below do not necessarily apply to all interpretations of the unit shapes 100 in that screen mesh 10.

[0015] If the printed conductive ink has uneven thickness, the resulting conductive pattern will have uneven film thickness and density, which may lead to deterioration of electrical properties. Therefore, it is preferable to be able to print conductive ink with small thickness variations.

[0016] As a result of extensive research, the present inventors have found that a mask having a mesh of a regular grid pattern of straight lines can cause thickness variations that depend on the period of the grid.

[0017] FIG. 2 shows a reference example of a screen mask in plan view. In the mesh of the screen mask shown in FIG. 2, linear wires 90 intersect vertically and horizontally in plan view. A mask portion 92 is provided on either side of a region 91 where a conductive pattern is to be formed. The portions that do not overlap with either the mask portion 92 or the wires 90 are openings 94. In the example of FIG. 2, non-openings 96 are generated by the mesh wires 90, crossing the region 91 where a conductive pattern is to be formed. In these non-openings 96, the conductive ink is not directly applied to the substrate during printing. Due to the fluidity of the conductive ink, some wraparound occurs, but the ink film thickness is thinner than in other regions. This results in thickness unevenness. In particular, as shown in FIG. 2, if the non-openings 96 are perpendicular to the extension direction of the conductive pattern, the cross-sectional area of ​​the conductive pattern (e.g., wiring or an antenna) becomes smaller at the non-openings 96, increasing the electrical resistance of the conductive pattern, which is a major problem. Furthermore, considering that a single circuit pattern contains wirings extending in various directions, it is easy for a portion to occur in which a wire 90 vertically crosses an area 91 in which a conductive pattern is to be formed, as shown in Figure 2.

[0018] In contrast, the screen mesh 10 according to this embodiment includes a portion having a structure in plan view in which a plurality of closed unit shapes 100, at least some of which are curved, are combined. Since at least some of the unit shapes 100 are curved, portions in which no openings continue in a specific direction are less likely to occur compared to the mesh shown in Figure 2. This reduces thickness unevenness during printing, and allows for a conductive pattern with good electrical properties to be obtained.

[0019] The screen mesh 10 according to this embodiment will be described in detail below.

[0020] The screen mesh 10 is made up of one or more filaments. In other words, it is preferable that the screen mesh 10 does not have a plate-shaped body with multiple openings. The material of the filaments is, for example, a metal such as stainless steel or a resin such as polyester or nylon. The thickness of the filaments is not particularly limited. The filaments may be wire-shaped or fibrous.

[0021] The thickness d (wire diameter) of the filament (see FIG. 8) is, for example, 0.01 mm or more and 0.1 mm or less. The thickness d (wire diameter) of the filament is not particularly limited, but is preferably 0.03 mm or less, and more preferably 0.02 mm or less. This allows for printing of fine patterns. The thickness d of the filament is preferably 0.02 mm or more, and more preferably 0.04 mm or more. This ensures high strength of the screen mesh 10. The length of the filament is not particularly limited, but is, for example, 1,000 mm or more. For example, the length of the filament is 10,000 times or more the equivalent circle diameter of the unit shape 100. The equivalent circle diameter of the unit shape 100 refers to the diameter of a perfect circle having the same area as the sum of the linear area of ​​the unit shape 100 and the internal area of ​​the unit shape 100. The length of the filament is 6,000 times or more the equivalent circle diameter of the cross section of the filament. The cross-sectional area and cross-sectional shape of the filament do not necessarily have to be uniform.

[0022] The thickness d of the filament is preferably 0.1 times or more, and more preferably 0.2 times or more, the outer diameter (diameter) of the unit shape 100. The thickness d of the filament is preferably 0.4 times or less, and more preferably 0.3 times or less, the outer diameter (diameter) of the unit shape 100.

[0023] The screen mesh 10 is formed, for example, by weaving multiple filaments. However, the multiple filaments in the screen mesh 10 do not have to be woven. For example, the multiple filaments may be overlapped or glued together. The fact that the screen mesh 10 or the unit shapes 100 have a certain shape or structure in a planar view means that the screen mesh 10 or the unit shapes 100 have a certain shape or structure in a projection (i.e., silhouette) of the screen mesh 10 or the unit shapes 100 viewed in a planar view. There are no limitations on how each unit shape 100 is realized with multiple filaments. That is, each unit shape 100 does not have to consist of a single filament. For example, as will be described later with reference to Figures 8 to 11, each unit shape 100 may be composed of a combination of multiple filaments. Each filament extends across multiple unit shapes 100. Unless otherwise specified, references to the shape of the unit shapes 100 refer to the shape of the unit shapes 100 in a projection.

[0024] In the screen mesh 10, the portions where the filaments overlap may be thicker than the other portions. However, the filaments may be partially removed at the overlapping portions. In other words, the overlapping portions may be the same thickness as the other portions.

[0025] The unit shape 100 is not particularly limited as long as it is a closed shape at least partially formed by a curve. The unit shape 100 may be, for example, substantially a circle or an ellipse. As another example, the unit shape 100 may be substantially a polygon with rounded corners. Examples of polygons with rounded corners include a triangle with rounded corners, a rectangle with rounded corners, a hexagon with rounded corners, and an octagon with rounded corners. The unit shape 100 may or may not have a portion that is convex toward the inside of the unit shape 100. As described above, the unit shape 100 is at least partially formed by a curve. It is preferable that the entire unit shape 100 is formed by a curve. However, the unit shape 100 may also be partially formed by a straight line. In a planar view, the orientation of the multiple unit shapes 100 may or may not be uniform.

[0026] Note that when the unit shape 100 is substantially a circle, an ellipse, or a polygon with rounded corners, this includes cases where the unit shape 100 has manufacturing errors, etc. In other words, the unit shape 100 does not need to be an exact circle, etc. For example, when the unit shape 100 is substantially a circle, this includes cases where the unit shape 100 is a circle with a circularity of 0.90 or more and 1.10 or less.

[0027] It is preferable that the shape of the unit shape 100 is smooth throughout. Specifically, it is preferable that the unit shape 100 is tangent continuous at all points. In other words, it is preferable that at all points of the unit shape 100, the tangent directions of the two curves that connect to each other at that point are the same. It is also more preferable that the radius of curvature of the unit shape 100 is continuous throughout the entire unit shape 100. It is preferable that each of the multiple unit shapes 100 does not have a point where the curvature changes discontinuously.

[0028] The size of the unit shape 100 is not particularly limited, but the circle-equivalent diameter of the unit shape 100 is, for example, 0.05 mm or more and 0.1 mm or less.

[0029] As described above, adjacent unit shapes 100 among the plurality of unit shapes 100 are in contact with or overlap with each other in at least one direction in a plan view. In particular, it is preferable that adjacent unit shapes 100 among the plurality of unit shapes 100 are in contact with or overlap with each other in at least two directions in a plan view. In particular, it is preferable that adjacent unit shapes 100 among the plurality of unit shapes 100 are in contact with or overlap with each other in at least two directions that are perpendicular to each other in a plan view. Adjacent unit shapes 100 among the plurality of unit shapes 100 may be in contact with or overlap with each other in three or four directions in a plan view.

[0030] A unit shape 100 may be in contact with another unit shape 100 by a line or by a point. Also, a unit shape 100 may overlap with another unit shape 100 by a line or by a point.

[0031] In the screen mesh 10, the number of overlapping filaments is not particularly limited, but is preferably four or less, and more preferably two or less. A small number of overlapping filaments makes it easier to produce the screen mesh 10. Furthermore, a small number of overlapping filaments can reduce the thickness (mesh thickness) of the screen mesh 10 at the points where multiple unit shapes 100 pass through.

[0032] The screen mesh 10 preferably has a periodic structure in plan view. In particular, from the viewpoint of ease of manufacturing the screen mesh 10, the screen mesh 10 preferably has a two-dimensional periodic structure in plan view. That is, the screen mesh 10 preferably has a periodic structure in which periodic units 120 are arranged two-dimensionally in plan view. The periodic units 120 may or may not coincide with the unit shapes 100. For example, in the example of FIG. 13 , which will be described in detail later, the periodic units 120 are larger than the unit shapes 100. The periodic units 120 are quadrilaterals such as squares, rectangles, or parallelograms.

[0033] The opening ratio of the screen mesh 10 is not particularly limited, but is preferably 40% or more, and more preferably 50% or more. This ensures good dischargeability even when using a highly viscous conductive ink. On the other hand, the opening ratio of the screen mesh 10 may be 60% or less, or even 50% or less. This ensures a high repulsive force of the screen mask, improving printing stability. The opening ratio is the area ratio of the openings (areas without filaments) in the screen mesh 10 in a plan view.

[0034] In plan view, the maximum spacing D of the filaments constituting the screen mesh 10 is preferably 0.08 mm or less, more preferably 0.05 mm or less. This allows for printing of fine patterns. Furthermore, the maximum spacing D is preferably 0.02 mm or more, more preferably 0.03 mm or more. For example, in the example of FIG. 1, the maximum spacing D is the inner diameter of a circle. In the example of FIG. 12, which will be described in detail, the maximum spacing D is the inner diameter of an ellipse in the major axis direction.

[0035] The mesh thickness of the screen mesh 10 is not particularly limited, but is preferably 0.03 mm or more, and more preferably 0.04 mm or more. The mesh thickness of the screen mesh 10 is preferably 0.06 mm or less, and more preferably 0.04 mm or less. The mesh thickness is the thickness at the points where the filaments overlap.

[0036] The area of ​​the openings in the screen mesh 10 is, for example, 0.001 mm 2 More than 0.016mm 2 The screen mesh 10 has a thickness of 1 mm in plan view. 2 The openings in the screen mesh 10 are those seen when the screen mesh 10 is viewed from above.

[0037] 3 and 4 are diagrams for explaining the degree of fluctuation M of the screen mesh 10. In Fig. 3 and Fig. 4, the periodic unit 120 is indicated by a dashed line. The degree of fluctuation M as follows can be considered as an index related to the magnitude of unevenness in the thickness of the coating film when screen printing is performed using the screen mesh 10.

[0038] First, a rectangular slit 140 is defined. In Fig. 3 and Fig. 4, the slit 140 is indicated by a dotted line. Each of Fig. 3 and Fig. 4 shows the slit 140 at a plurality of positions. On the screen mesh 10, the slit 140 is moved in the direction of the short side by the length of the short side of the slit 140, and the opening area S through the slit 140 at each position of the slit 140 is identified. Then, the maximum value of the identified opening areas S is defined as S. max , the minimum value is S min When this is done, the variability M is: max -S min ) / (S max +S min ) is calculated based on the relationship

[0039] When the periodic unit 120 is a square, the length of the long side of the slit 140 is the length of one side of the square that is the periodic unit 120. When the periodic unit 120 is a rectangle, the length of the long side of the slit 140 is the length of the long side of the rectangle that is the periodic unit 120.

[0040] The length of the short side of the slit 140 is set to half the line width of the filaments that make up the screen mesh 10 in plan view.

[0041] The opening area S determined according to the position of the slit 140 means the area where the conductive ink is directly applied to the substrate in the region within the slit 140. The greater the variation in the opening area S according to the position of the slit 140, that is, the greater the degree of variation M, the greater the variation in the area where the conductive ink is directly applied to the substrate will be depending on the position on the screen mesh 10, resulting in greater thickness unevenness.

[0042] It has been confirmed that a simulation using the relationship between the position of the slit 140 and the opening area S can accurately reproduce the thickness distribution of the conductive ink that is actually printed.

[0043] Here, the degree of fluctuation M depends on the orientation of the slits 140 relative to the screen mesh 10.

[0044] When the periodic unit 120 is a square, the state in which the long side of the slit 140 is parallel to any side of the square that is the periodic unit 120 is called the first state, as shown in Fig. 3. When the periodic unit 120 is a rectangle, the state in which the long side of the slit 140 is parallel to the long side of the rectangle that is the periodic unit 120 is called the first state.

[0045] On the other hand, as shown in FIG. 4, a state in which the orientation of the slit 140 is rotated 45° clockwise from the first state is called a second state.

[0046] The number of positions of the slits 140 that determine the opening area S is set to a number that allows determination of the maximum and minimum values ​​of the opening area S in the screen mesh 10. For example, if the screen mesh 10 has periodicity in the direction in which the slits 140 are moved, the slits 140 may be moved by the same number of periods.

[0047] The degree of fluctuation M of the screen mesh 10 is preferably 0.8 or less, and more preferably 0.6 or less, when the orientation of the slits 140 is in the first state.

[0048] The degree of fluctuation M of the screen mesh 10 is preferably 0.8 or less, and more preferably 0.6 or less, when the orientation of the slits 140 is in the second state.

[0049] The variability M of the screen mesh 10 is preferably 0.8 or less, preferably 0.6 or less, and more preferably 0.5 or less, whether the orientation of the slits 140 is in the first state or the second state.

[0050] The absolute value of the difference between the degree of fluctuation M in the first state and the degree of fluctuation M in the second state of the screen mesh 10 is preferably 0.3 or less, and more preferably 0.2 or less.

[0051] When the periodic unit 120 is a square, there are two possible orientations of the side of the periodic unit 120 that can be parallel to the long side of the slit 140 in the first state, and each of the above preferred conditions only needs to be met when at least one of the orientations is selected.

[0052] Several specific examples of the screen mesh 10 according to this embodiment will be described in detail below.

[0053] <Example 1> 1 and 5 are diagrams showing a first example of the structure of a screen mesh 10 according to this embodiment. Each of FIGS. 1 and 5 shows a portion of the screen mesh 10 in a plan view. In FIGS. 1 and 5, one unit shape 100 is indicated by diagonal hatching. As shown in FIG. 1, in the first example, each of the multiple unit shapes 100 can be said to be substantially circular. On the other hand, as shown in FIG. 5, in the first example, each of the multiple unit shapes 100 can also be interpreted as being diamond-shaped (a shape in which each side of a rectangle is curved inward). The following describes the case in which the unit shapes 100 are interpreted as circles, as in FIG. 1.

[0054] In the first example, the unit shape 100 is entirely made up of curves. Also, in the first example, the unit shape 100 is tangent continuous at all points and has a uniform radius of curvature.

[0055] In the first example, adjacent unit shapes 100 are in contact with each other in the x-axis and y-axis directions. On the other hand, adjacent unit shapes 100 are not in contact with each other and do not overlap with each other in diagonal directions (i.e., directions intersecting both the x-axis and y-axis directions). Specifically, adjacent unit shapes 100a and 100c are in contact with each other in the x-axis direction. Furthermore, adjacent unit shapes 100a and 100b are in contact with each other in the y-axis direction. On the other hand, adjacent unit shapes 100a and 100d are not in contact with each other in the diagonal direction. Furthermore, adjacent unit shapes 100c and 100b are not in contact with each other in the diagonal direction. That is, in the first example, adjacent unit shapes 100 are in contact with each other in two directions.

[0056] In the first example, the screen mesh 10 has a two-dimensional periodic structure in a plan view. One periodic unit 120 is indicated by a dashed line in Fig. 1. In the first example, the periodic unit 120 is a square.

[0057] <Example 2> FIG. 6 is a diagram showing a second example of the structure of the screen mesh 10 according to this embodiment. FIG. 6 shows a portion of the screen mesh 10 in a plan view. In FIG. 6, one unit shape 100 is indicated by diagonal hatching. As shown in FIG. 6, in the second example, each of the multiple unit shapes 100 can be said to be substantially circular. On the other hand, in the second example, each of the multiple unit shapes 100 can also be interpreted as being diamond-shaped (a shape in which each side of a rectangle is curved inward), or each of the multiple unit shapes 100 can also be interpreted as being leaf-shaped or eye-shaped. Below, a case where the unit shapes 100 are interpreted as being circles, as in FIG. 6, will be described.

[0058] In the second example, adjacent unit shapes 100 are in contact with each other in the x-axis direction and the y-axis direction. Furthermore, adjacent unit shapes 100 overlap each other in diagonal directions (i.e., directions intersecting both the x-axis direction and the y-axis direction). In other words, in the second example, adjacent unit shapes 100 are in contact with each other or overlap each other in all four directions.

[0059] In the second example, the plurality of unit shapes 100 includes a first group consisting of two or more unit shapes 100 among the plurality of unit shapes 100, and a second group consisting of two or more other unit shapes 100 among the plurality of unit shapes 100. In each of the first and second groups, adjacent unit shapes 100 are in contact with each other in at least one direction in plan view. The first and second groups overlap in plan view.

[0060] Fig. 7 is a diagram showing the first group and the second group with distinction. In Fig. 7, the first group is indicated by diagonal hatching, and the second group is indicated by a black line. Note that in Fig. 7, the second group is shown behind the first group for ease of distinction, but the front-to-back relationship between the first group and the second group is not limited as long as the silhouette as a whole is as shown in Fig. 7. For example, the second group may be located in front of the first group in some parts, and the first group may be located in front of the second group in other parts.

[0061] In the second example, the first and second groups each have the same configuration as in the first example.

[0062] It is preferable that the unit shapes 100 constituting the first group and the unit shapes 100 constituting the second group have the same size. For example, in a plan view, it is preferable that the average diameter of the circumscribing circles of the two or more unit shapes 100 constituting the first group is 0.95 to 1.05 times the average diameter of the circumscribing circles of the two or more unit shapes 100 constituting the second group. The average diameter of the circumscribing circles is, for example, the average within a square with sides of 2 cm.

[0063] Furthermore, it is preferable that the unit shapes 100 constituting the first group and the unit shapes 100 constituting the second group have the same shape. For example, in a plan view, it is preferable that the average circularity of the two or more unit shapes 100 constituting the first group is 0.95 to 1.05 times the average circularity of the two or more unit shapes 100 constituting the second group. The average circularity is, for example, the average within a square with sides of 2 cm.

[0064] In the second example, the unit shape 100 is entirely made up of curves. Also, in the second example, the unit shape 100 is tangent continuous at all points and has a uniform radius of curvature.

[0065] In the second example, at least one junction between the unit shapes 100 belonging to the first group and at least one junction between the unit shapes 100 belonging to the second group overlap in plan view. Four unit shapes 100 pass through the point where these two junctions overlap.

[0066] In the second example, the screen mesh 10 has a two-dimensional periodic structure in plan view. One periodic unit 120 is indicated by a dashed line in Fig. 6. In the second example, the periodic unit is a square.

[0067] 8 to 11 are diagrams for explaining an example of a manufacturing method for the screen mesh 10 according to the second example. The screen mesh 10 according to the second example can be constructed, for example, by combining (for example, interweaving) a plurality of filaments as shown by the black lines in Figs. 8 to 11.

[0068] 6 to 11 have been described with reference to the case where the unit shapes 100 are circles, but when the unit shapes 100 are ellipses, the screen mesh 10 may have a structure in which the first and second groups overlap in a plan view. That is, the first and second groups may each have a configuration similar to that of FIG. 12, which will be described in detail later. Alternatively, the unit shapes 100 in one of the first and second groups may be circles, and the unit shapes 100 in the other may be ellipses.

[0069] <Example 3> FIG. 12 is a diagram showing a third example of the structure of the screen mesh 10 according to this embodiment. FIG. 12 shows a portion of the screen mesh 10 in a plan view. In FIG. 12, one unit shape 100 is indicated by diagonal hatching. As shown in FIG. 12, in the third example, each of the multiple unit shapes 100 can be said to be substantially elliptical. On the other hand, in the third example, each of the multiple unit shapes 100 can also be interpreted as being diamond-shaped (a shape in which each side of a rectangle is curved inward). Below, a case where the unit shapes 100 are interpreted as ellipses, as in FIG. 12, will be described.

[0070] In the third example, the entire unit shape 100 is made up of curves. Also, in the third example, the unit shape 100 is tangent continuous at all points, and the radius of curvature of the unit shape 100 is continuous throughout the entire unit shape 100.

[0071] From the viewpoint of ensuring curvature and reducing thickness unevenness in printing, the major axis (outer diameter) of the ellipse as the unit shape 100 is preferably 2 times or less, more preferably 1.6 times or less, the minor axis (outer diameter). The major axis (outer diameter) of the ellipse as the unit shape 100 is preferably 1.3 times or more, more preferably more than 1 time, the minor axis (outer diameter).

[0072] In the third example, adjacent unit shapes 100 are in contact with each other in the x-axis and y-axis directions. On the other hand, adjacent unit shapes 100 are not in contact with each other and do not overlap with each other in the diagonal directions (i.e., directions intersecting both the x-axis and y-axis directions). In other words, in the third example, adjacent unit shapes 100 are in contact with each other in two directions.

[0073] In the third example, the screen mesh 10 has a two-dimensional periodic structure in plan view. One periodic unit 120 is indicated by a dashed line in Fig. 12. In the third example, the periodic unit 120 is rectangular.

[0074] <Example 4> Fig. 13 is a diagram showing a fourth example of the structure of the screen mesh 10 according to this embodiment. Fig. 13 shows a part of the screen mesh 10 in a plan view. In Fig. 13, one unit shape 100 is indicated by diagonal hatching.

[0075] In the fourth example, the entire unit shape 100 is made up of curves. Also, in the fourth example, the unit shape 100 includes a point that is not tangent continuous. The unit shape 100 in the fourth example has a portion that is convex toward the inside of the unit shape 100 and a portion that is convex toward the outside of the unit shape 100.

[0076] In the fourth example, adjacent unit shapes 100 are in contact with each other at lines in the x-axis and y-axis directions. Also, in the fourth example, adjacent unit shapes 100 are in contact with each other at points in diagonal directions (i.e., directions intersecting both the x-axis and y-axis directions). That is, in the fourth example, adjacent unit shapes 100 are in contact with each other in all four directions.

[0077] In the fourth example, the orientations of adjacent unit shapes 100 in the x-axis direction are different from each other. Specifically, the orientation of a unit shape 100 is different by 90° from that of another unit shape 100 adjacent to it in the x-axis direction. Furthermore, the orientations of adjacent unit shapes 100 in the y-axis direction are different from each other. Specifically, the orientation of a unit shape 100 is different by 90° from that of another unit shape 100 adjacent to it in the y-axis direction. On the other hand, the orientations of diagonally adjacent unit shapes 100 are the same.

[0078] In the fourth example, the screen mesh 10 has a two-dimensional periodic structure in plan view. One periodic unit 120 is indicated by a dashed line in Fig. 13. In the fourth example, the periodic unit 120 is a square.

[0079] Although several specific examples of the screen mesh 10 according to the present embodiment have been described in detail above, the screen mesh 10 is not limited to these examples.

[0080] 14 and 15 are diagrams illustrating the structure of the screen mask 20 according to this embodiment. The screen mask 20 according to this embodiment includes the screen mesh 10 according to this embodiment and a mask layer 210 attached to the screen mesh 10. Fig. 14 shows a part of the screen mask 20 in a plan view, and Fig. 15 shows a cross-sectional view of a part of the screen mask 20.

[0081] The screen mask 20 can be produced by applying a mask layer 210 to the screen mesh 10. The mask layer 210 is, for example, an emulsion or a metal. The thickness of the mask layer 210 is not particularly limited, but is, for example, 0.005 mm or more and 0.1 mm or less.

[0082] The mask layer 210 has openings (through holes) corresponding to the pattern to be printed. FIG. 16 is a diagram illustrating an example of openings in the mask layer 210. In FIG. 16, the blackened areas correspond to the openings. In the example of FIG. 16, the mask layer 210 has openings corresponding to the shape of an antenna. However, the shape and size of the openings shown in FIG. 16 are merely examples, and the openings provided in the mask layer 210 are not limited to this example. The mask layer 210 may have openings corresponding to, for example, a circuit pattern, or openings corresponding to wiring.

[0083] The relationship between the shape of the screen mesh 10 and the opening pattern in the screen mask 20 is not particularly limited. For example, even if the opening pattern includes line portions corresponding to wiring or the like, the orientation of the unit shapes 100 relative to the extending direction of the line portions is not particularly limited. Furthermore, the positional relationship between the position of the line portions and the unit shapes 100 is not particularly limited. Therefore, the openings provided in the mask layer 210 can include multiple line portions extending in different directions.

[0084] The minimum width w of the openings provided in the mask layer 210, i.e., the minimum width of the pattern printed using the screen mask 20, is, for example, 0.8 mm or less. This allows for a fine conductive pattern to be obtained. The minimum width w is, for example, 0.1 mm or more. This allows for stable printing of the pattern.

[0085] It can be said that thickness unevenness is more likely to occur when the ratio of the maximum spacing D or the thickness d of the filaments to the minimum width w of the openings in the mask layer 210 is large than when the ratio is small. In contrast, with the screen mesh 10 according to this embodiment, even when the ratio of the maximum spacing D or the thickness d of the filaments to the minimum width w is large, thickness unevenness can be reduced because at least a portion of the unit shape 100 is curved. That is, the screen mesh 10 according to this embodiment is suitable for use when the ratio of the maximum spacing D or the thickness d of the filaments to the minimum width w of the openings in the mask layer 210 is large. For example, the maximum spacing D of the filaments constituting the screen mesh 10 in a plan view may be 0.5 times or more the minimum width w of the openings in the mask layer 210. The thickness d of the filaments constituting the screen mesh 10 may be 0.1 times or more the minimum width w of the openings in the mask layer 210. The maximum spacing D is, for example, 1 time or less the minimum width w. The thickness d of the filament is, for example, 0.5 times or less the minimum width w.

[0086] On the other hand, it is preferable that the maximum spacing D is 0.5 times or less the minimum width w, which can improve the stability of 210. It is also preferable that the thickness d of the filament is 0.05 times or less the minimum width w, which can improve the dischargeability of the conductive ink.

[0087] The method for manufacturing the conductive pattern according to this embodiment will be described below. The method for manufacturing the conductive pattern according to this embodiment includes a step of performing screen printing using a screen mask 20.

[0088] 17 is a cross-sectional view illustrating the configuration of a structure 30 including a conductive pattern 320. The conductive pattern 320 can be, for example, at least one of a wiring pattern, a circuit pattern, an electrode pattern, a pattern having an electromagnetic wave shielding function, and an antenna pattern. The structure 30 can be, for example, at least one of a wireless communication tag (such as an RF tag), a circuit, an electromagnetic wave shielding film, a planar heating element, and an electronic device. Examples of electronic devices include sensors, solar cells, secondary batteries, membrane switches, etc.

[0089] In the screen printing step, the conductive ink is applied to the substrate 310 by screen printing. In this way, a conductive ink pattern can be formed on the substrate 310. This conductive pattern 320 has a shape and size corresponding to the opening pattern of the mask layer 210.

[0090] The thickness of the conductive ink film applied to the substrate 310 is not particularly limited, but is, for example, 0.01 mm or more and 0.04 mm or less.

[0091] The conductive ink contains conductive particles. The conductive particles may contain at least one element selected from the group consisting of silver, copper, gold, aluminum, platinum, palladium, iridium, tungsten, nickel, tantalum, lead, and zinc. In particular, from the viewpoints of availability and good conductivity, it is preferable that the conductive particles contain at least one element selected from the group consisting of silver and copper.

[0092] The conductive ink may further contain at least one of a solvent, a resin, and a binder. Specific examples of the resin or binder include polyvinylpyrrolidone, polyester, epoxy resin, (meth)acrylic resin, polyvinyl acetal, cellulose resin (e.g., ethyl cellulose), and phenol resin. The solvent may include at least one of water and an organic solvent.

[0093] The viscosity of the conductive ink at 25°C is not particularly limited, but may be 200 Pa·s or higher. In this case, the conductive particle content in the conductive ink can be increased. Furthermore, when the viscosity of the conductive ink is high, thickness unevenness is more likely to occur than when the viscosity is low. However, with the screen mesh 10 according to this embodiment, at least a portion of the unit shapes 100 are curved, which reduces thickness unevenness. In other words, the screen mesh 10 according to this embodiment is suitable for use when the viscosity of the conductive ink is high. The viscosity of the conductive ink at 25°C is, for example, 300 Pa·s or less. On the other hand, from the viewpoint of printability, the viscosity of the conductive ink at 25°C is preferably 100 Pa·s or less.

[0094] The substrate 310 is, for example, in the form of a film, a sheet, or a plate. The substrate 310 may or may not be flexible. The substrate 310 is, for example, a resin or paper. The substrate 310 is, for example, at least one selected from the group consisting of polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyolefins such as polyethylene and polypropylene, polyimide, and paper.

[0095] In screen printing, the orientation of the squeegee is arbitrary. That is, the orientation of the squeegee relative to the orientation of the unit shapes 100 of the screen mesh 10 is not particularly limited. However, when the unit shapes 100 are ellipses, it is preferable that the moving direction of the squeegee be parallel to the major axis of the ellipses in order to reduce thickness unevenness.

[0096] The method for manufacturing the conductive pattern 320 according to this embodiment may further include a sintering step after the screen printing step. In the step of sintering the conductive ink, the printed conductive ink pattern is heated to sinter the conductive particles contained in the conductive ink. This allows the conductive pattern 320 corresponding to the conductive ink pattern to be obtained. The thickness of the conductive pattern 320 is not particularly limited, but is, for example, 0.003 mm or more and 0.03 mm or less.

[0097] (Second embodiment) FIG. 24 is a diagram illustrating the flow of a manufacturing method for a conductive substrate 400 according to the second embodiment. The manufacturing method for a conductive substrate 400 according to this embodiment includes a printing step, a transfer step, and a pressure step. In the printing step, a conductive ink containing conductive particles is screen-printed onto a first substrate 41 using the screen mask 20 according to the first embodiment, thereby forming a conductive pattern 45 on the first substrate 41. In the transfer step, the conductive pattern 45 is transferred to a second substrate 42 different from the first substrate 41. In the pressure step, pressure is applied to a laminate including the second substrate 42 and the conductive pattern 45. These steps will be described in detail below.

[0098] In this embodiment, pressure is applied to the laminate of the second substrate 42 and the conductive pattern 45. Therefore, in the finally obtained conductive substrate 400, the adhesiveness of the conductive pattern 45 to the second substrate 42 is better than when the conductive pattern is simply printed on a substrate. In particular, in this embodiment, the screen mask 20 according to the first embodiment is used to screen-print a conductive ink containing conductive particles onto the first substrate 41, thereby obtaining a conductive pattern 45 with little thickness variation. Therefore, pressure can be applied uniformly, and the adhesiveness of the entire conductive pattern 45 can be improved.

[0099] Furthermore, it is thought that a finer and more accurate conductive pattern 45 can be formed by forming the pattern by a method called "transfer" rather than by directly printing the conductive ink onto the second substrate 42 to form the pattern.

[0100] The first substrate 41 is not particularly limited as long as the conductive pattern 45 can be easily separated. Specific examples of the first substrate 41 include resin films. More specific examples include resin films with a silicone resin applied to the surface and resin films with silicone resin kneaded into them. The main material of these resin films is not particularly limited, but in consideration of strength and cost, polyester-based materials are preferred, and polyethylene terephthalate is more preferred. Various commercially available films under names such as "release film" and "peeling film" can also be used as the first substrate 41.

[0101] Furthermore, release paper can also be used as the first substrate 41. Release paper typically refers to laminated paper in which a thin film-like resin is laminated on paper to give it easy peelability. Release paper is sometimes expressed as release paper. As for the release paper, various types of release paper available on the market can be used as appropriate.

[0102] The first substrate 41 may be in the form of a film or a sheet, or may be in the form of a cylinder, for example. For example, the first substrate 41 may be a roll whose surface is made of metal or resin, on which the conductive pattern 45 can be formed, and from which the conductive pattern 45 can be easily separated. By using a cylindrical first substrate 41, it is possible to expect improvements in the productivity of the conductive substrate 400. The first substrate 41 may be disposable or may be reused.

[0103] The conductive ink is as described in the first embodiment. In the printing process, the screen mask 20 described in the first embodiment is used to screen-print the conductive ink on the first substrate 41. The screen printing using the screen mask 20 is as described in the first embodiment.

[0104] When the conductive ink contains a solvent, the method for manufacturing the conductive substrate 400 according to this embodiment may further include a step of volatilizing the solvent in the conductive pattern 45. Heating conditions for volatilizing the solvent are, for example, 50 to 150°C for 1 to 60 minutes. However, the temperature is preferably set so as not to damage the first substrate 41. Heating can be performed, for example, by applying hot air to the conductive pattern 45. Another example is by placing the first substrate 41 and the conductive pattern 45 on a hot plate. Light heating is also possible. Specific examples include heating using a far-infrared heating furnace (IR oven) or Adphos NIR (ultra-near infrared), heating with a high-brightness LED, and laser heating.

[0105] It is preferable that the conductive particles in the conductive pattern 45 are not substantially sintered after being printed. Incidentally, the conductive particles are usually sintered by a known method after the pressure step described below. It is also preferable that the conductive pattern 45 is not substantially cured. Specifically, even if the conductive ink contains a curable resin or a crosslinking agent, it is preferable that the curable resin or crosslinking agent in the conductive pattern 45 is substantially unreacted after being printed.

[0106] In the transfer step, the conductive pattern 45 is transferred from the first substrate 41 to a second substrate 42 that is different from the first substrate 41. In the example of Fig. 24, the conductive pattern 45 is transferred to the second substrate 42 via an adhesive layer 43.

[0107] The second substrate 42 is usually in the form of a film, sheet, or plate. From the viewpoint of industrial productivity, the shape of the second substrate 42 is preferably one of these. The second substrate 42 is preferably flexible. By employing a flexible second substrate 42, a flexible printed circuit (FPC) can be manufactured. By using a flexible second substrate 42, it becomes easier to apply pressure using a "roll" in the pressure application step described below. This is preferable from the viewpoint of mass productivity. Just to be clear, the second substrate 42 may be a rigid substrate that does not have flexibility.

[0108] Considering cost and end use, the second substrate 42 is preferably at least one selected from the group consisting of polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyolefins such as polyethylene and polypropylene, polyimide, polycarbonate, and paper. Here, the paper may be coated paper (paper whose surface is coated with a coating agent) or ordinary uncoated paper. Furthermore, the second substrate 42 is not limited to PET, and any general resin film can be used. Furthermore, the second substrate 42 may be transparent or opaque. Examples of opaque resin films include foamed resin films or foamed resin sheets, such as foamed PET film.

[0109] In this embodiment, even without heating or with heating at a relatively low temperature in the pressurizing step, sufficiently good adhesion of the conductive pattern 45 to the second substrate 42 can be obtained. Therefore, a second substrate 42 made of a low heat resistance material such as polyester, polyolefin, polycarbonate, or paper can also be suitably used as the substrate.

[0110] The adhesive layer 43 is preferably thermosetting or photocurable. More preferably, the adhesive layer 43 is formed of a thermosetting resin material or a photocurable resin material. When the second substrate 42 is light-transmitting, the adhesive layer 43 can be cured by irradiating light from the second substrate 42 side by making the adhesive layer 43 photocurable. When the second substrate 42 is not light-transmitting, the adhesive layer 43 can be cured by irradiating light from the adhesive layer 43 side, or by heating by making the adhesive layer 43 thermosetting. Just to be clear, the adhesive layer 43 may have both thermosetting and photocurable properties, or may have only one of thermosetting and photocurable properties.

[0111] Examples of materials that can be used to form the adhesive layer 43 include various thermosetting or photocurable resin materials. Specific examples include thermosetting or photocurable resin materials such as epoxy resin-containing materials, polymerizable (meth)acrylate-containing materials, urethane-based materials, urethane (meth)acrylate-containing materials, and silicone-based materials. The adhesive layer 43 can also be made of commercially available products. For example, the adhesive layer 43 can be made of various thermosetting or photocurable resin materials that are known or commercially available as hard coating agents. Additionally, various thermosetting or photocurable resin materials that are known or commercially available as primers can also be used.

[0112] When the adhesive layer 43 is thermosetting, it is preferable to form the adhesive layer 43 so that the thermosetting proceeds at a heating temperature that does not damage the second base material 42. For example, when the second base material 42 is made of a resin, it is preferable to design the adhesive layer 43 so that the curing reaction proceeds sufficiently when heated at a temperature lower than the glass transition temperature of the resin.

[0113] The thickness of the adhesive layer 43 is not particularly limited, but considering the need to obtain sufficient adhesion and to appropriately control penetration into the temporary pattern, it is preferably 1 to 30 μm, and more preferably 5 to 15 μm. The adhesive layer 43 may be a single layer or may have two or more layers. For example, if the second substrate 42 is paper, a two-layer adhesive layer 43 may be used in consideration of penetration into the fibrous paper. In this case, the first adhesive layer closest to the paper plays a role of "sealing."

[0114] In the transfer step, the conductive pattern 45 is brought into contact with the adhesive layer 43 provided on the surface of the second substrate 42. This causes the conductive pattern 45 to be transferred to the surface of the adhesive layer 43. Then, the first substrate 41 is peeled off from the conductive pattern 45. However, the step of peeling off the first substrate 41 from the conductive pattern 45 may be performed after the adhesive layer curing step described below and before the pressure application step.

[0115] In the example of Figure 24, an adhesive layer curing step is performed between the transfer step and the pressure step, in which the curing of the adhesive layer 43 progresses. Note that in Figure 24, the laminate is depicted upside down for the transfer step and the adhesive layer curing step. The adhesive layer 43 can be cured by light such as ultraviolet light if the adhesive layer 43 is photocurable. Alternatively, the adhesive layer 43 can be cured by heating if the adhesive layer 43 is thermosetting. The light irradiation and heating conditions may be adjusted and optimized as appropriate depending on the specific material that constitutes the adhesive layer 43. However, when curing the adhesive layer 43 by heating, care must be taken to ensure that the second substrate 42 is not damaged by the heat.

[0116] In the adhesive layer curing step, it is preferable to completely cure the adhesive layer 43, but it is also possible to cure it to a certain extent, without completely curing it.

[0117] In the pressing step, a laminate including the second substrate 42 and the conductive pattern 45 is pressed. In the example of FIG. 24 , a laminate including the second substrate 42, the adhesive layer 43, and the conductive pattern 45 is placed on a flat plate, and a roll 48 is placed on top of the laminate. The roll 48 is rolled to pressurize the laminate. In this way, the pressing step may use one or more rolls 48. However, the pressing method is not limited to the example of FIG. 24 . As another example, the laminate including the second substrate 42, the adhesive layer 43, and the conductive pattern 45 may be sandwiched between two rolls 48 with their sides facing each other and the two rolls 48 rotated. In this case, the laminate is pressed while being transported between the two rolls 48. In addition, in FIG. 24 , the laminate is pressed with the second substrate 42 facing the flat plate and the conductive pattern 45 facing the roll 48. However, the laminate may also be pressed with the second substrate 42 facing the roll 48 and the conductive pattern 45 facing the flat plate. As yet another example, the laminate may be pressed by sandwiching it between two flat plates (i.e., two flat surfaces).

[0118] By not applying too great a pressure P to the conductive pattern 45 in the pressing step, it is possible to prevent damage to the second base material 42 and the conductive pattern 45. Incidentally, if the second base material 42 has sufficient strength, the pressure P can be increased to improve the adhesion of the finally obtained conductive pattern 45 to the second base material 42.

[0119] In the method for manufacturing the conductive base material 400 according to this embodiment, after the pressing step, the conductive pattern 45 is sintered by a known method (for example, heating, etc.) to obtain the conductive base material 400.

[0120] In the method for manufacturing the conductive substrate 400 according to this embodiment, the conductive substrate 400 is obtained, which includes at least the second substrate 42 and the conductive pattern 45. In the example of FIG. 24 , the conductive substrate 400 further includes an adhesive layer 43 between the second substrate 42 and the conductive pattern 45.

[0121] The present inventors have discovered that in a manufacturing method in which a conductive pattern is transferred and pressed by a roll, if the conductive pattern has large thickness unevenness, cracks are likely to occur in the conductive pattern due to the pressure applied by the roll. In contrast, in the manufacturing method of the conductive substrate 400 according to this embodiment, a conductive pattern 45 with small thickness unevenness is obtained by performing screen printing using the screen mask 20 according to the first embodiment. Therefore, even when the conductive pattern 45 is transferred and pressed by a roll 48, the effect of preventing cracks from occurring in the conductive pattern 45 is achieved. This will be described in detail below.

[0122] 25 is a diagram illustrating a method for manufacturing a conductive substrate according to a reference example. In this reference example, the screen mask 20 according to the first embodiment is not used in the printing process, and a conductive pattern 55 having large thickness variations is formed on a first substrate 51.

[0123] In the reference example, when the second base material 52 having the adhesive layer 53 attached thereto is brought into contact with the conductive pattern 55, a portion of the conductive pattern 55 does not come into contact with the adhesive layer 53 due to unevenness in the thickness of the conductive pattern 55. The portion of the conductive pattern 55 that does not come into contact with the adhesive layer 53 remains floating above the adhesive layer 53 even after the adhesive layer curing step. When pressure is applied by the roll 58 in this state, the conductive pattern 55 peels up from the adhesive layer 53 in the portion of the conductive pattern 55 that does not come into contact with the adhesive layer 53, causing cracks in the conductive pattern 55.

[0124] In order to prevent such cracks in conductive pattern 55 with large thickness variations, it is conceivable to ensure that the thickness of adhesive layer 53 is equal to or greater than the difference in elevation of the surface of conductive pattern 55. However, such a method raises the problems of an increased thickness of the conductive base material that is ultimately obtained, and an increased cost due to the formation of thick adhesive layer 53.

[0125] In the method for manufacturing the conductive substrate 400 according to this embodiment, the screen mask 20 according to the first embodiment is used to perform screen printing, thereby obtaining a conductive pattern 45 with little thickness variation. Therefore, the entire conductive pattern 45 is likely to come into contact with the adhesive layer 43 without floating, that is, is well adhered to the second substrate 42. As a result, an effect is obtained in which cracks are unlikely to occur in the conductive pattern 45 even when pressure is applied by the roll 48.

[0126] In the method for producing the conductive substrate 400 according to this embodiment, a laminate including the second substrate 42 and the conductive pattern 45 is pressurized. Therefore, in the finally obtained conductive substrate 400, the adhesiveness of the conductive pattern 45 to the second substrate 42 is better than when the conductive pattern is simply printed on the substrate. In addition, in the method for producing the conductive substrate 400 according to this embodiment, the screen mask 20 according to the first embodiment is used for screen printing, thereby obtaining a conductive pattern 45 with little thickness variation. Therefore, even when the conductive pattern 45 is transferred and pressed by a roll, the effect of preventing cracks from occurring in the conductive pattern 45 is obtained. [Example]

[0127] The present embodiment will be described in detail below with reference to examples, but the present embodiment is not limited to the descriptions of these examples.

[0128] <Comparative Example> For a screen mesh made of straight wires that intersect vertically and horizontally in a plan view, the degree of variation M in the first and second states was determined using the method described in the first embodiment. The opening ratio of the screen mesh in Example 1 was 0.56.

[0129] FIG. 18 is a diagram showing the relationship between a screen mesh according to a comparative example and multiple slit positions in a first state. In FIG. 18, the silhouette outline of the screen mesh in a plan view is shown by a solid line, and slits arranged at multiple positions are shown by dotted lines. The same applies to FIG. 20, which will be described later. FIG. 19 is a graph showing the relationship between the slit position and the opening area S when the slit is in the first state in the comparative example. In the graph showing the relationship between the slit position and the opening area S, the slit position shown on the horizontal axis corresponds to the slit number when the multiple slit positions are numbered in order from the left. The opening area S shown on the vertical axis is the maximum value S max is normalized to be 1. The same applies to Figs. 21 to 23 described later.

[0130] Fig. 20 is a diagram showing the relationship between a screen mesh according to a comparative example and the positions of multiple slits in the second state. Fig. 21 is a graph showing the relationship between the slit positions and the opening area S when the slits are in the second state in the comparative example.

[0131] Example 1 For the screen mesh shown in FIG. 1 of the first embodiment, the degree of fluctuation M in the first and second states was determined using the same method as described in the first embodiment. That is, in Example 1, the unit shape was a circle. The opening ratio of the screen mesh according to Example 1 was 0.62. The thickness d of the filaments was 0.10 times the outer diameter (diameter) of the circle as the unit shape.

[0132] The relationship between the screen mesh according to Example 1 and the positions of the slits in the first state is as shown in Fig. 3. Fig. 22 is a graph showing the relationship between the slit positions and the opening area S when the slits are in the first state in Example 1.

[0133] The relationship between the screen mesh according to Example 1 and the positions of the slits in the second state is as shown in Fig. 4. Fig. 23 is a graph showing the relationship between the slit positions and the opening area S when the slits are in the second state in Example 1.

[0134] <Example 2> For the screen mesh of Example 2, the degree of fluctuation M in the first and second states was determined using the method described in the first embodiment. The screen mesh of Example 2 was the same as that of Example 1, except that the opening ratio was set to 0.47. In Example 2, the thickness d of the filaments was 0.15 times the outer diameter (diameter) of a circle as a unit shape.

[0135] Example 3 For the screen mesh shown in FIG. 6 of the first embodiment, the degree of fluctuation M in the first and second states was determined using the same method as described in the first embodiment. That is, in Example 3, the unit shape was a circle. The opening ratio of the screen mesh according to Example 3 was 0.51. The thickness d of the filaments was 0.10 times the outer diameter (diameter) of the circle as the unit shape.

[0136] Example 4 For the screen mesh shown in FIG. 12 of the first embodiment, the degree of fluctuation M in the first and second states was determined using the method described in the first embodiment. That is, in Example 4, the unit shape was an ellipse. The opening ratio of the screen mesh according to Example 4 was 0.71. The major axis (outer diameter) of the ellipse as the unit shape was 1.3 times the minor axis (outer diameter).

[0137] <Example 5> For the screen mesh of Example 5, the degree of fluctuation M in the first state and the second state was determined using the method described in the first embodiment. The screen mesh of Example 5 was the same as Example 4, except that the opening ratio was 0.66 and the major axis (outer diameter) of the ellipse as the unit shape was 1.7 times the minor axis (outer diameter).

[0138] Example 6 For the screen mesh of Example 6, the degree of fluctuation M in the first state and the second state was determined using the method described in the first embodiment. The screen mesh of Example 6 was the same as that of Example 4, except that the opening ratio was 0.63 and the major axis (outer diameter) of the ellipse as the unit shape was 2.0 times the minor axis (outer diameter).

[0139] Example 7 For the screen mesh shown in Fig. 13 of the first embodiment, the degree of fluctuation M in the first and second states was determined using the same method as described in the first embodiment. That is, in Example 7, the unit shape included a portion that was convex toward the inside of the unit shape. The opening ratio of the screen mesh of Example 7 was 0.44.

[0140] Example 8 For the screen mesh of Example 8, the degree of fluctuation M in the first state and the second state was determined using the method described in the first embodiment. The screen mesh of Example 8 was the same as Example 7, except that the opening ratio was set to 0.67.

[0141] The fluctuation degree M of the screen meshes according to the comparative example and examples 1 to 8 is summarized in Table 1. Table 1 also shows the opening ratio of each screen mesh and the absolute value (referred to as the "difference Δ") of the difference obtained by subtracting the fluctuation degree M in the second state from the fluctuation degree M in the first state.

[0142] [Table 1]

[0143] The fluctuation rate of the screen mesh according to the comparative example was 1.00 when the slit orientation was in state 1. Therefore, it can be seen that the screen mesh according to the comparative example can cause large thickness variations during printing.

[0144] On the other hand, the fluctuation rates of the screen meshes according to Examples 1 to 8 were all less than 1 when the slit orientation was in the first state and when the slit orientation was in the second state, indicating that thickness unevenness was reduced compared to the comparative example.

[0145] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted. [Explanation of symbols]

[0146] 10 screen mesh 20 Screen Mask 30 Structure 41 First base material 42 Second base material 43 Adhesive layer 45 Conductive Pattern 48 rolls 51 1st base material 52 Second base material 53 Adhesive layer 55 Conductive Pattern 58 rolls 90 wire 91 areas 92 Mask Section 94 Aperture 96 Non-opening 100 unit shape 120 cycle units 140 slit 210 Mask Layer 310 Base material 320 Conductive Pattern 400 Conductive substrate

Claims

1. A screen mesh for printing conductive ink, comprising: The structure includes a portion having a structure in which a plurality of closed unit shapes, at least a portion of which is made up of curves, are combined in a plan view, Each of the plurality of unit shapes is composed of one or more filaments, In a plan view, adjacent unit shapes among the plurality of unit shapes are in contact with or overlap each other in at least one direction. Screen mesh.

2. The screen mesh according to claim 1, Each of the plurality of unit shapes is substantially a circle or an ellipse. Screen mesh.

3. The screen mesh according to claim 2, Each of the plurality of unit shapes is substantially circular. Screen mesh.

4. The screen mesh according to claim 2, Each of the plurality of unit shapes is substantially elliptical. Screen mesh.

5. The screen mesh according to claim 1 or 2, the plurality of unit shapes include a first group consisting of two or more unit shapes from the plurality of unit shapes, and a second group consisting of two or more other unit shapes from the plurality of unit shapes, In each of the first group and the second group, adjacent unit shapes are in contact with each other in at least one direction in a plan view; The first group and the second group overlap in a plan view. Screen mesh.

6. The screen mesh according to claim 5, At least one contact point between the unit shapes belonging to the first group and at least one contact point between the unit shapes belonging to the second group overlap in a plan view. Screen mesh.

7. The screen mesh according to claim 5, an average of diameters of circumscribing circles of the two or more unit shapes constituting the first group is 0.95 to 1.05 times the average of diameters of circumscribing circles of the two or more unit shapes constituting the second group in a plan view; In a plan view, the average circularity of the two or more unit shapes constituting the first group is 0.95 to 1.05 times the average circularity of the two or more unit shapes constituting the second group. Screen mesh.

8. The screen mesh according to claim 1 or 2, In plan view, the screen mesh has a periodic structure in which periodic units are arranged two-dimensionally, the periodic unit is a square, On the screen mesh, the rectangular slits are moved in the direction of the short side by the length of the short side of the slit, and the opening area through the slit at each slit position is identified, and the maximum value of the identified multiple opening areas is designated as S. ｍａｘ , the minimum value is S ｍｉｎ When this is done, the degree of fluctuation M = (S ｍａｘ -S ｍｉｎ ) / (S ｍａｘ +S ｍｉｎ ) is 0.8 or less when the orientation of the slit is in the first state and when the orientation of the slit is in the second state, the length of the long side of the slit is the length of one side of the square that is the periodic unit, and the length of the short side of the slit is half the line width of the filamentous body in a plan view, the first state is a state in which a long side of the slit is parallel to any side of the square that is the periodic unit, The second state is a state in which the orientation of the slit is rotated 45° clockwise from the first state. Screen mesh.

9. The screen mesh according to claim 1 or 2, In plan view, the screen mesh has a periodic structure in which periodic units are arranged two-dimensionally, the periodic unit is a rectangle, On the screen mesh, the rectangular slits are moved in the direction of the short side by the length of the short side of the slit, and the opening area through the slit at each slit position is identified, and the maximum value of the identified multiple opening areas is designated as S. ｍａｘ , the minimum value is S ｍｉｎ When this is done, the degree of fluctuation M = (S ｍａｘ -S ｍｉｎ ) / (S ｍａｘ +S ｍｉｎ ) is 0.8 or less when the orientation of the slit is in the first state and when the orientation of the slit is in the second state, the length of the long side of the slit is the length of the long side of the rectangle that is the periodic unit, and the length of the short side of the slit is half the line width of the filamentous body in a plan view, the first state is a state in which a long side of the slit is parallel to a long side of a rectangle that is the periodic unit, The second state is a state in which the orientation of the slit is rotated 45° clockwise from the first state. Screen mesh.

10. The screen mesh according to claim 1 or 2; a mask layer attached to the screen mesh; Screen mask.

11. A step of performing screen printing using the screen mask according to claim 10 is included. A method for manufacturing a conductive pattern.

12. forming a conductive pattern on a first substrate by screen-printing a conductive ink containing conductive particles on the first substrate using the screen mask according to claim 10; transferring the conductive pattern to a second substrate different from the first substrate; and applying pressure to a laminate including the second base material and the conductive pattern. A method for producing a conductive substrate.

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