Screen mask and method of manufacturing printed matter

Abstract

To provide a screen mask capable of improving the accuracy of a printing shape, and a method for manufacturing the screen mask.SOLUTION: A screen mask according to an embodiment includes a support material having a hole through which a coating material can pass, and a mask film which is provided in the support material and in which a pattern opening capable of holding the coating material is formed, in which the mask film has a convex portion protruding toward a printing surface side formed in a part of a surface on the printing surface side, and a roughness of a surface of a reference portion which is at least a part of the surface on the printing surface side is larger than a roughness of a surface of the convex portion on the printing surface side.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a screen mask and a printed matter. [Background technology]

[0002] Screen printing, a printing technique, is a method of forming a desired print on a substrate using a screen mask with a predetermined pattern of openings formed from a resin composition on a mesh support material. This screen printing method is used for various printing processes, such as printing of wiring, electrodes, and fluorescent materials, and is used in a variety of fields, including electronic components.

[0003] For example, the screen mask includes a mesh having holes that allow the coating material to pass through, and a mask film having pattern openings formed in the mesh. The pattern openings formed in the mask film have a shape corresponding to, for example, a printing pattern and a predetermined width.

[0004] When a printed product is produced using a screen mask, a coating material is supplied to a mask film, and the mask film and a substrate to be printed are brought into contact with each other by squeegeeing, thereby transferring the coating material to the substrate to be printed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-169783 Summary of the Invention [Problem to be solved by the invention]

[0006] In such a screen mask, if the separation of the screen from the substrate to be printed, known as "plate separation," is prevented immediately after squeegeeing, capillary action and peeling electrification can cause the ink to bleed, reducing the accuracy of the printed shape.

[0007] Therefore, there is a need for a screen mask and a method for manufacturing the screen mask that can improve the accuracy of the printing shape. [Means for solving the problem]

[0008] A screen mask according to one embodiment comprises a support material having holes that allow the coating material to pass through, and a mask film provided on the support material and having pattern openings that can hold the coating material, wherein the mask film has a convex portion that protrudes toward the printing surface on a portion of its surface on the printing surface side, and the surface roughness of a reference portion, which is at least a portion of the surface on the printing surface, is greater than the surface roughness of the convex portion on the printing surface side. [Effects of the Invention]

[0009] According to the embodiments of the present invention, it is possible to provide a screen mask and a method for manufacturing the screen mask, which can improve the accuracy of the print shape. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of a screen printing apparatus according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of the screen mask according to the embodiment. [Figure 3] 3A and 3B are cross-sectional views of the screen mask according to the embodiment and a screen mask according to a comparative example. [Figure 4] An image showing the configuration of part of the screen mask. [Figure 5] 3A to 3C are explanatory views showing a method for manufacturing the screen mask. [Figure 6] FIG. 10 is a cross-sectional view of a screen mask according to a second embodiment. [Figure 7] FIG. 10 is an explanatory diagram showing the configuration of a screen mask according to another embodiment. [Figure 8] FIG. 10 is a perspective view showing the configuration of a screen mask according to another embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing the configuration of a screen mask according to another embodiment. [Figure 10]FIG. 10 is a cross-sectional view showing the configuration of a screen mask according to another embodiment. [Figure 11] FIG. 10 is a cross-sectional view showing the configuration of a screen mask according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] A screen printing apparatus 10, a screen mask 20, and a method for manufacturing the screen mask 20 according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is an explanatory diagram showing the screen printing apparatus 10 according to this embodiment. FIG. 2 is a perspective view of the screen mask 20, and FIG. 3 is a cross-sectional view of the screen mask 20 and a portion of a screen mask 120 according to a comparative example. FIG. 4 is an image showing the configuration of a portion of the screen mask 20, and FIG. 5 is an explanatory diagram showing the manufacturing method. Note that in each figure, the configuration is enlarged, reduced, or omitted as appropriate for ease of explanation. In the figures, arrows X, Y, and Z indicate three mutually perpendicular directions.

[0012] As shown in Figure 1, the screen printing apparatus 10 includes a screen mask 20, a holding member 12 that holds the printing medium Ba facing the front surface (one side) 20a, which is the printing side of the screen mask 20, a squeegee 13 that is configured to be movable while in contact with the back surface (other side) 20b, which is the opposite side to the printing side of the screen mask 20, a moving unit that moves the squeegee 13, and a support unit that supports the screen mask 20 facing the printing medium Ba.

[0013] The screen printing apparatus 10 forms various printing materials in predetermined patterns on the surface of a printing medium Ba. For example, the screen printing apparatus 10 is used in the manufacture of chip components (capacitors, chip resistors, inductors, thermistors, etc.), touch panels, liquid crystal display (LCD) substrate seals, LTCC (Low Temperature Co-fired ceramics) substrates, solar cell electrodes, and other electronic components.

[0014] 1 and 2, the screen mask 20 includes a frame 21, a mesh 22 that is a support material stretched over the frame 21, and a mask film 23 formed on the mesh 22. In the screen mask 20, the side that faces the surface of the printing medium Ba when printing is performed is called the front surface 20a, and the opposite side, to which the coating material Pe is supplied, is called the back surface 20b.

[0015] The frame 21 has two pairs of parallel edges and is configured in the shape of a frame with, for example, a rectangular opening of a desired size. The frame 21 supports the outer periphery of the mesh 22, and the mesh 22 is stretched across the opening. In this embodiment, as an example, the dimension of the opening of the frame 21 in the Y direction is 275 mm, and the dimension of the opening in the X direction is 275 mm.

[0016] The frame 21 also functions as a frame for holding a predetermined amount of coating material Pe on the rear surface of the mask film 23. The frame 21 and the mesh 22 are joined at a joint with, for example, a synthetic rubber or cyanoacrylate adhesive.

[0017] The mesh 22 is a woven fabric formed by weaving warp threads 22a and weft threads 22b, and has many holes 22c that allow the coating material Pe to pass through. The warp threads 22a and weft threads 22b are wires made of metal such as stainless steel or tungsten, or fibers made of resin such as polyester. The warp threads 22a and weft threads 22b each extend obliquely with respect to the movement direction (first direction) of the squeegee 13, for example.

[0018] A mask film 23 having a predetermined pattern of openings 23a is formed on the mesh 22. That is, the mesh 22 holds the mask film 23 in the opening portions of the frame 21.

[0019] The mask film 23 is a layer made of a photocurable resin composition, such as PVA, PVAc, silicone resin, acrylic resin, or epoxy resin. For example, as shown in Fig. 3, the mask film 23 is made of multiple layers, such as a two-layer structure formed by laminating a base layer 23b and a cover layer 23c. As an example, the cover layer 23c is made of a material having the same flexibility as the base layer 23b or a material having greater flexibility than the base layer 23b.

[0020] The thickness of the mask film 23, which is the dimension in the Z direction, is set to, for example, 10 μm or more and 100 μm or less.

[0021] The mask film 23 is formed on the mesh 22 and is placed in the opening portion of the frame 21. A predetermined pattern opening 23a for printing is formed in the mask film 23 by exposure.

[0022] The minimum opening width of the pattern opening 23a, i.e., the width dimension of the opening at the narrowest part of the pattern opening 23a, is 30 μm or less. Here, as an example, the dimension at the surface of the mask film 23, i.e., the surface 20a facing the printing medium Ba, is used as the standard.

[0023] The pattern openings 23a are pattern holes having a shape corresponding to the printing pattern, and penetrate the mask film 23 in the thickness direction (depth direction). The shape of the printing pattern can be set as appropriate. As an example, in this embodiment, the pattern shape is a pattern in which multiple identical pattern units are arranged in a matrix. The pattern openings 23a are configured to be able to hold a coating material.

[0024] For example, the pattern opening 23a may have a plurality of independent openings or may be a continuous opening. For example, the pattern opening 23a may be set to various shapes, such as a slit-like line pattern, or an opening with a rectangular or circular shape. The depth dimension of the pattern opening 23a may vary depending on the location.

[0025] The mask film 23 forms a printed portion where the photosensitive resin is not present in the pattern openings 23a and the coating material Pe can pass from the back surface to the front surface through the holes in the mesh 22. The areas of the mask film 23 other than the pattern openings 23a where the holes in the mesh 22 are blocked with photosensitive resin form a non-printed portion that does not allow the ink serving as the coating material Pe to pass through.

[0026] In this embodiment, the thickness of the mask film 23 varies depending on the location. For example, in this embodiment, a convex portion 23d that protrudes toward the printing surface is formed on a portion of the surface of the mask film 23 on the printing surface side, and a concave portion 23e that serves as a reference portion retracted to the opposite side from the printing surface side is formed on at least a portion of the surface on the printing surface side by the convex portion 23d.

[0027] For example, a convex portion 23d is formed at the edge portion of a first opening of a pattern opening 23a formed in a predetermined pattern shape in the mask film 23.

[0028] That is, mask film 23 has convex portions that protrude toward the printing surface side and concave portions that are recessed from the printing surface side relative to the convex portions. For example, concave portions 23e are formed on the surface of base layer 23b facing the printing surface, and convex portions 23d are formed on the surface of cover layer 23c facing the printing surface. In other words, concave portions 23e, which are reference portions, are formed by base layer 23b, and convex portions 23d are formed by cover layer 23c.

[0029] The mask film 23 is configured so that the surface roughness R1 of the surface of the printing surface side of the convex portions 23d is smaller than the surface roughness R2 of the surface of the printing surface side of the concave portions 23e. In this embodiment, the convex portions 23d are formed in areas including at least some of the edges of the pattern openings, and the concave portions 23e are formed in areas farther from the edges than the convex portions 23d.

[0030] Specifically, in this embodiment, in any region of the pattern opening 23a, a convex portion 23d protruding toward the printing surface is formed at the edge (peripheral portion) of the opening on the printing surface side. The region other than the convex portion 23d constitutes the concave portion 23e. The convex portion 23d and the concave portion 23e may be formed in multiple locations. For example, the convex portion 23d may be formed along the pattern shape of the mask film 23, or a pattern may exist in which the convex portion 23d is not formed. In this embodiment, as an example, the region other than the convex portion 23d is the concave portion 23e, and the roughness of the bottom surface of the concave portion 23e is greater than that of the convex portion 23d. However, on the surface of the mask film 23 on the printing surface side, a reference portion having a surface roughness greater than that of the convex portion 23d may be formed over the entire region except for the convex portion 23d, or may be formed only in a portion thereof. In other words, on the opposing surface, which is the surface of the mask film 23 on the printing surface side, a portion of the region other than the convex portion 23d may include a portion with a lower surface roughness. For example, in order to ensure peelability, it is preferable that the reference portion be formed in an area other than the convex portion 23d that is equal to or greater than the surface area of ​​the convex portion 23d, and more preferably, it is formed in most of the area excluding the convex portion 23d, for example, an area that is equal to or greater than 80% of the area.

[0031] In this embodiment, for example, the thickness of the base layer 23b is set to 15 μm or more and 50 μm or less. Furthermore, the surface roughness of the printed surface of the base layer 23b, when expressed as the arithmetic mean roughness Ra, which is the average value of irregularities over a reference length, is Ra 0.2 μm or more and Ra 0.5 μm or less. The measurement was performed using a 50x lens of a laser microscope VK-X3000 manufactured by KEYENCE Corporation, with a reference length of 0.1 mm or more and 0.2 mm or less. If the target object is wavy or curved, an appropriate cutoff may be applied. When a cutoff is applied, λc is set to one-fifth of the reference length.

[0032] The cover layer 23c has a thickness T of 1 μm or more and 5 μm or less The surface roughness of the printing surface of the cover layer 23c is Ra 0.01 μm or more and less than Ra 0.2 μm.

[0033] The surface roughness R1 of the printing cotton side of the convex portions 23d formed in the cover layer 23c is Ra0.01 μm or more and less than Ra0.2 μm, and the surface roughness R2 of the printing surface of the concave portions 23e formed in the base layer 23b is configured to be in the range of Ra0.2 μm or more and Ra0.5 μm or less.

[0034] When the pattern openings 23a are linear, they are formed along the edges of both sides of the pattern openings 23a within a predetermined distance from the edges. The width W1 of the protrusions 23d of the cover layer 23c, which is perpendicular to the line extension direction of the pattern openings 23a, is preferably 20 μm or more and 50 μm or less. Furthermore, the thickness T1 of the protrusions 23d on the printing surface is preferably 1 μm or more and 5 μm or less. The width W of the protrusions 23d may be constant, or may be configured such that some portions are wider or narrower.

[0035] For example, the surface of the printing surface of the recessed portion 23e is matte-finished. That is, in this embodiment, the surface of the base layer 23b that forms the printing surface of the recessed portion 23e is matte-finished, so that the surface roughness of the recessed portion 23e is made coarse, and therefore the surface of the printing surface of the protruding portion 23d is made finer than the surface of other regions.

[0036] The mesh 22 on which the mask film 23 is formed is configured to be elastically deformable so that it is flexed and deformed by, for example, the pressing force of the squeegee 13 and restored to its original shape when the pressing force is released. With the coating material Pe held in the pattern openings 23a of the mask film 23, the mask film 23 moves toward and away from the printing medium Ba due to the elastic deformation of the mesh 22, and the coating material Pe is transferred from the pattern openings 23a to the printing medium Ba arranged opposite the printing surface side of the mask film 23.

[0037] The squeegee 13 is formed, for example, in the shape of a thin plate from a material such as urethane rubber, silicone rubber, synthetic rubber, metal, or plastic. For example, the squeegee 13 is chamfered to reduce the thickness of its tip. The squeegee 13 is configured to be movable relative to the frame 21. For example, the squeegee 13 has a length that spans the entire length of the area of ​​the mask film 23 in a direction perpendicular to the direction of movement. When the tip portion 13a of the squeegee 13 abuts against the back surface 20b of the screen mask 20 and is pressed against the front surface, the squeegee 13 moves in the direction of movement along arrow A in FIG. 1, thereby pressing against the entire surface of the mask film 23 and forcing the coating material Pe to the front surface from the pattern openings 23a in which the coating material Pe has been pre-filled.

[0038] The support section supports the frame 21 in parallel with and at a predetermined distance from the printing medium Ba. The movement section moves the squeegee 13 at a predetermined speed in a predetermined direction.

[0039] Next, a method for manufacturing the screen mask 20 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram showing the method for manufacturing the screen mask 20. The method for manufacturing the screen mask 20 includes a first layer forming step ST1, a surface treatment step ST2, a first patterning step ST3, a second layer forming step ST4, a second patterning step ST5, and an etching step ST6.

[0040] In the first layer formation step ST1, a first emulsion Pm1 is applied to a support material having pores that allow the coating material to pass through, forming a first emulsion layer. The first emulsion Pm1 is, for example, a photocurable resin, such as a liquid containing polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), silicone resin, acrylic resin, or epoxy resin. Specifically, first, a coating process is performed in which the mesh 22 is coated with the first emulsion Pm1 while the mesh 22 is attached to the frame 21 so that it is approximately flat, thereby forming a flat base layer 23b on the mesh 22. Since the thickness varies depending on the number of coatings, multiple coatings may be performed as necessary. In addition, the film thickness may be measured after drying, and additional coatings may be performed if necessary. In this embodiment, the thickness of the emulsion Pm1 is set so that the emulsion thickness of the first emulsion layer is approximately 5 to 20 μm after drying.

[0041] Next, in the surface treatment step ST2, the surface roughness of the base layer emulsion Pm1 is set. For example, the surface is treated to have a surface roughness of Ra 0.2 μm or more and Ra 0.5 μm or less by etching using corona discharge or atmospheric pressure plasma, or by transferring a PET film roughened by alkaline solution etching to the emulsion surface (the wet surface immediately after coating). For example, the surface roughness can be set by attaching a film with a predetermined surface roughness to the surface and then peeling it off.

[0042] Next, a first patterning step ST3 is performed in which the first emulsion layer with the set roughness is exposed to a predetermined first exposure pattern by maskless exposure without using a photomask. Specifically, the surface side of the base layer 23b is placed in the predetermined exposure pattern area facing a light source such as an ultraviolet lamp or ultraviolet LED, and light is irradiated from the light source to illuminate the surface of the emulsion. The first exposed portion of the base layer 23b that is exposed by the first exposure step becomes a first emulsion hardened portion (first photo-crosslinked portion) Pa1 that is hardened by ultraviolet light. Meanwhile, the first unexposed portion Pb1 of the base layer 23b, which is a portion excluding the first exposed portion Pa1, becomes an unhardened portion Pb1 where the emulsion does not harden. The first unhardened portion Pb1 (first unexposed portion) forms a first removal target portion that will be removed in a later step to form the base opening. In this way, the base layer 23b is patterned, and the first removal target portion that will be removed in a later etching step to form the base opening is formed.

[0043] Next, in the second layer forming step ST4, a coating process is performed to coat the base layer 23b with the second emulsion Pm2, thereby forming a cover layer 23c with the second emulsion Pm2 on the printing surface side of the base layer 23b.

[0044] For example, in the second layer formation step ST4, the cover layer 23c is formed by coating with the same emulsion as the base layer 23b, or a different emulsion that is more flexible than the base layer 23b. Then, a smooth (flat) PET film is transferred to the surface of the print side of the cover layer 23c, or a smooth (flat) DFR (dry film resist) is attached, for example, to achieve a mirror finish so that the surface has a finer surface roughness than the base layer 23b. A seasoning step may be performed here, in which the frame is left to stand for about three hours under conditions for maskless exposure processing, thereby bringing the frame temperature to the same level as during the first maskless exposure processing.

[0045] Next, a second patterning step ST5 is performed, in which exposure is performed using a second exposure pattern different from the first exposure pattern. In the second patterning step ST5, a second maskless exposure process is performed, for example, using a maskless exposure method that does not use a photomask. Specifically, in a predetermined second exposure pattern area, the surface side of the emulsion Pm2 is placed facing a light source such as an ultraviolet lamp or ultraviolet LED, and light is irradiated from the light source to illuminate the surface of the emulsion Pm2. Through the second exposure process, the ultraviolet-irradiated portions of the emulsion Pm2 corresponding to the portions of the exposure pattern area are hardened by the ultraviolet light. For example, the portions where a smooth (flat) and convex surface are desired are exposed. That is, the second exposed portions of the cover layer 23c that are exposed by the second exposure process form second emulsion-hardened portions (second photo-crosslinked portions) Pa2 that are hardened by ultraviolet light. The second emulsion-hardened portions Pa2 constitute the convex portions 23d. On the other hand, the second unexposed portions of the cover layer 23c that are the portions excluding the second exposed portions become second unhardened portions Pb2 in which the emulsion does not harden. The second unhardened portions Pb2 include second portions to be removed that will be removed in a later step to form the pattern openings 23a including the base openings.

[0046] The first exposure process and the second exposure process are both exposure processes in which light is irradiated from the printing surface side, and the second exposure process hardens a predetermined range by exposing from the same direction as the first exposure process. That is, the second exposure process hardens a part of the second emulsion layer that is on one side of the first exposed area hardened in the first exposure process and that becomes the convex portion 23d on the edge of the pattern opening 23a.

[0047] Then, in the etching process ST6 (development process), at least one side of the mask film is washed away with water or a solvent. This process forms pattern openings 23a that penetrate from the front side to the back side in the thickness direction, where the uncured portions Pb1 and Pb2 of the emulsions Pm1 and Pm2 are washed away, and convex portions 23d are formed along the pattern openings 23a. In other words, the development leaves behind rough surface areas and smooth, convex surface areas.

[0048] Next, a method for producing a printed matter by a screen printing method using the screen printing apparatus 10 according to this embodiment will be described with reference to Fig. 1. First, the front side of the screen mask 20 is placed facing the surface of the printing medium Ba held by the holding member 12.

[0049] Then, a highly viscous paste-like coating material Pe is supplied from the rear surface side of the screen mask 20, that is, the surface opposite to the printing medium Ba, and the coating material Pe is filled into the pattern openings 23a.

[0050] Next, a squeegee 13 is placed on the back surface 20b of the screen mask 20, i.e., the surface opposite the printing surface. At this time, for example, the squeegee 13 is placed at a predetermined angle with respect to the front surface of the printing medium Ba. Then, the squeegee 13 is moved at a predetermined speed while pressing the mesh 22 and the back surface of the mask film 23 toward the printing medium Ba with a predetermined printing pressure. The squeegee 13 presses the mask film 23 over the entire back surface of the mask film 23. The pressure of the squeegee 13 deforms the mask film 23 so that the pressed portion is displaced toward the front surface and comes into contact with the printing medium Ba. The coating material Pe pressed by the passage of the squeegee 13 is pushed out from the pattern openings 23a toward the printing medium Ba.

[0051] After the squeegee 13 has passed, the mask film 23 and mesh 22 deform and restore their original shape, separating from the print medium Ba. A portion of the coating material Pe is transferred and remains on the print medium Ba, completing the pattern printing on the print medium Ba and completing the print. At this time, a portion of the backside of the coating material Pe remains on the mask film 23 side. The coating material Pe may be made of various materials, including metal and resin, and various materials are used depending on the type of printing target, such as electronic components or displays. The amount of coating material Pe applied is adjusted according to the depth of the pattern openings 23a.

[0052] The screen mask 20, screen printing apparatus 10, and screen printing method configured as described above can form a two-layer structure with different surface roughness using a maskless exposure machine with a simple configuration, thereby preventing sticking and facilitating smooth release of the mask surface from the substrate to be printed. For example, sticking between the emulsion film of the screen and the substrate to be printed can cause delays in release, but this method can suppress sticking at the contact surfaces.

[0053] Furthermore, by forming the convex portions 23d with small surface roughness on the edges of the pattern openings 23a, bleeding during printing can be prevented and a desirable print shape can be obtained.

[0054] [Second embodiment] A screen mask 20A and a method for manufacturing a screen mask according to a second embodiment of the present invention will be described below with reference to Fig. 6. Fig. 6 is an explanatory diagram of the screen mask 20A according to this embodiment. The screen mask 20A according to this embodiment has a configuration in which the convex portions 23f (second convex portions) are arranged outside the concave portions 23e, which are reference portions. In other words, the concave portions 23e are formed in areas including at least part of the edges of the pattern openings, and the convex portions 23f are formed in areas farther away from the edges than the concave portions 23e. Other configurations are similar to those of the screen mask 20 according to the first embodiment, and therefore a common description will be omitted. As shown in Figure 1, the screen printing apparatus 10 includes a screen mask 20, a holding member 12 that holds the printing medium Ba facing the front surface (one side) 20a, which is the printing side of the screen mask 20, a squeegee 13 that is configured to be movable while in contact with the back surface (other side) 20b, which is the opposite side to the printing side of the screen mask 20, a moving unit that moves the squeegee 13, and a support unit that supports the screen mask 20 facing the printing medium Ba.

[0055] 1 and 2, the screen mask 20 includes a frame 21, a mesh 22 that is a support material stretched over the frame 21, and a mask film 23 formed on the mesh 22. In the screen mask 20, the side that faces the surface of the printing medium Ba when printing is performed is called the front surface 20a, and the opposite side, to which the coating material Pe is supplied, is called the back surface 20b.

[0056] The mask film 23 is a layer made of a photocurable resin composition, such as PVA, PVAc, silicone resin, acrylic resin, or epoxy resin. For example, as shown in FIG. 3, the mask film 23 is made up of multiple layers, such as a two-layer structure formed by laminating a base layer 23b and a cover layer 23c. As an example, the cover layer 23c is made of a material that is more flexible than the base layer 23b. For example, the convex portions 23f formed in the cover layer 23c have higher resilience than the base layer 23b and are therefore more likely to stretch back.

[0057] The thickness of the mask film 23, which is the dimension in the Z direction, is set to, for example, 10 μm or more and 100 μm or less.

[0058] The mask film 23 is formed on the mesh 22 and is placed in the opening portion of the frame 21. A predetermined pattern opening 23a for printing is formed in the mask film 23 by exposure.

[0059] The minimum opening width of the pattern opening 23a, i.e., the width dimension of the opening at the narrowest part of the pattern opening 23a, is 30 μm or less. Here, as an example, the dimension at the surface of the mask film 23, i.e., the surface 20a facing the printing medium Ba, is used as the standard.

[0060] The pattern openings 23a are pattern holes having a shape corresponding to the printing pattern, and penetrate the mask film 23 in the thickness direction (depth direction). The shape of the printing pattern can be set as appropriate. As an example, in this embodiment, the pattern shape is a pattern in which multiple identical pattern units are arranged in a matrix. The pattern openings 23a are configured to be able to hold a coating material.

[0061] For example, the pattern opening 23a may have a plurality of independent openings or may be a continuous opening. For example, the pattern opening 23a may be set to various shapes, such as a slit-like line pattern, or an opening with a rectangular or circular shape. The depth dimension of the pattern opening 23a may vary depending on the location.

[0062] The mask film 23 forms a printed portion where the photosensitive resin is not present in the pattern openings 23a and the coating material Pe can pass from the back surface to the front surface through the holes in the mesh 22. The areas of the mask film 23 other than the pattern openings 23a where the holes in the mesh 22 are blocked with photosensitive resin form a non-printed portion that does not allow the ink serving as the coating material Pe to pass through.

[0063] In this embodiment, the thickness of the mask film 23 varies depending on the region. For example, in this embodiment, the printing surface of the mask film 23 has convex portions 23f that protrude toward the printing surface in a predetermined region, and concave portions 23e that are recessed from the convex portions 23f to the side opposite the printing surface.

[0064] For example, a recess 23e is formed in a region including the edge Eg of the first opening of a pattern opening 23a formed in a predetermined pattern shape on the mask film 23, and a protrusion 23f is formed in a region farther from the edge Eg than the recess 23e.

[0065] That is, mask film 23 has convex portions 23f that protrude toward the printing surface side and concave portions 23e that are recessed from convex portions 23f toward the printing surface side. For example, concave portions 23e are formed on the surface of base layer 23b facing the printing surface side, and convex portions 23f are formed on the surface of cover layer 23c facing the printing surface side.

[0066] The mask film 23 is configured so that the surface roughness R1 of the printing surface side of the protrusions 23f is smaller than the surface roughness R2 of the printing surface side of the recesses 23e. In this embodiment, the recesses 23e are formed in areas including at least some of the edges of the pattern openings, and the protrusions 23f are formed in areas farther from the edges than the recesses 23e.

[0067] Specifically, in this embodiment, in any region of the pattern opening 23a, recesses 23e are formed on both sides of the edge (rim portion) of the opening on the printing surface side, and recesses 23e are formed outside the recesses 23e. For example, in the mask film 23, at least one of the protrusions 23f and the recesses 23e, or both, are distributed and arranged in multiple locations depending on the pattern shape.

[0068] In this embodiment, for example, the thickness of the base layer 23b is set to 25 μm, and the surface roughness of the printing surface of the base layer 23b is Ra 0.2 μm or more and Ra 0.5 μm or less.

[0069] The cover layer 23c has a thickness T2 of 10 μm to 200 μm. The surface roughness of the printing surface of the cover layer 23c is set to be equal to or greater than Ra 0.01 μm and less than Ra 0.2 μm.

[0070] That is, the surface roughness R1 of the printing surface of the convex portions 23f formed in the cover layer 23c is Ra0.01 μm or more and less than Ra0.2 μm, and the surface roughness R2 of the printing surface of the concave portions 23e formed in the base layer 23b is Ra0.2 μm or more and Ra0.5 μm or less.

[0071] When the pattern opening 23a is a line-shaped pattern, recesses 23e are formed in regions including the edges Eg on both sides of the pattern opening 23a.

[0072] Furthermore, the protrusions 23f of the cover layer 23c are disposed at a distance W2 of 10 mm to 100 mm from the edge Eg in the width direction perpendicular to the line extension direction of the pattern opening 23a. That is, the distance from the edge of the protrusions 23f closest to the pattern opening 23a to the edge of the pattern opening 23a is set to 10 mm to 100 mm. Therefore, in this embodiment, the recess 23e is formed in a region ranging from 10 mm to 100 mm from the edge Eg.

[0073] Furthermore, it is preferable that the dimension T1 in the thickness direction of the protrusions 23f on the printing surface is 10 μm or more and 200 μm or less. The recesses 23e may be formed in an area that spans multiple pattern openings 23a. Furthermore, the protrusions 23f formed by the cover layer 23c are made of a flexible material that is easily elastically deformed.

[0074] For example, the surface of the printing surface side of the recessed portions 23e is matte-finished. That is, in this embodiment, the surface of the base layer 23b that forms the printing surface of the recessed portions 23e is matte-finished, so that the recessed portions 23e are configured to have a coarse texture, and therefore the surface of the printing surface side of the protruding portions 23f is configured to have a finer texture than the surface portions of other regions.

[0075] The mesh 22 on which the mask film 23 is formed is configured to be elastically deformable so that it is flexed and deformed by, for example, the pressing force of the squeegee 13 and restored to its original shape when the pressing force is released. With the coating material Pe held in the pattern openings 23a of the mask film 23, the mask film 23 moves toward and away from the printing medium Ba due to the elastic deformation of the mesh 22, and the coating material Pe is transferred from the pattern openings 23a to the printing medium Ba arranged opposite the printing surface side of the mask film 23.

[0076] The squeegee 13 is formed, for example, in the shape of a thin plate from a material such as urethane rubber, silicone rubber, synthetic rubber, metal, or plastic. For example, the squeegee 13 is chamfered to reduce the thickness of its tip. The squeegee 13 is configured to be movable relative to the frame 21. For example, the squeegee 13 has a length that spans the entire length of the area of ​​the mask film 23 in a direction perpendicular to the direction of movement. When the tip portion 13a of the squeegee 13 abuts against the back surface 20b of the screen mask 20 and is pressed against the front surface, the squeegee 13 moves in the direction of movement along arrow A in FIG. 1, thereby pressing against the entire surface of the mask film 23 and forcing the coating material Pe to the front surface from the pattern openings 23a in which the coating material Pe has been pre-filled.

[0077] According to the screen mask 20 and the method for manufacturing the screen mask 20 of this embodiment, the recesses are formed in areas that include at least some of the edges of the pattern openings, and the protrusions are formed in areas that are farther from the edges than the recesses, thereby assisting in plate release and making it easier to ensure the printing shape.

[0078] That is, the mesh 22 is supported by a portion protruding toward the printing surface at a predetermined thickness at a location a predetermined distance from the area where the pattern openings 23a are located, and the outer convex portions 23f away from the pattern openings 23a are present, so that the mesh 22 supported by the convex portions 23f is pushed up in the direction away from the printing medium. Therefore, the concave portions 23e located inside the convex portions 23f are lifted by the outer convex portions 23f, shortening the plate release time. In addition, the inner concave portions 23e have a greater surface roughness, which further promotes plate release.

[0079] Furthermore, by using a material for the protrusions 23f that is more flexible than the inner recesses, the mesh 22 of the protrusions 23f, which serve as the support parts, is stretched, and the elastic force ensures good plate release. Furthermore, because the protrusions 23f are configured to be easily elastically deformed, they deform due to an external force during printing so as to come into close contact with the printing object, and then generate a restoring force to return them to their original shape, and this restoration can promote plate release by separating the protrusions 23f from the printing object.

[0080] Furthermore, the convex portion 23d of the cover layer 23c is positioned at a distance W2 from the edge Eg in the width direction perpendicular to the extension direction of the line of the pattern opening 23a, which is 10 mm or more and 100 mm or less, thereby ensuring the plate release effect due to elastic force while making it difficult for the opening pattern to bleed.

[0081] The present invention is not limited to the above-described embodiments, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention.

[0082] In each of the above embodiments, when a first emulsion and a second emulsion are used, the first emulsion and the second emulsion may be made of different materials or may be made of the same material.

[0083] Furthermore, the manufacturing method and the regions of the base layer and cover layer are not limited to those described above.

[0084] For example, as shown in FIG. 7, the openings of the first exposure pattern and the second exposure pattern may be different sizes. That is, in the manufacturing process of the mask film 23, the first exposure pattern may be a pattern that forms a base opening wider than the pattern width of the second exposure pattern, taking into account misalignment with the second pattern to be laminated in a later process. Therefore, the portion that forms the inner wall of the pattern opening 23a is hardened together with the convex portion. That is, a portion of the second emulsion hardened portion Pa2 forms the convex portion 23d, and another portion forms the inner wall of the pattern opening 23a. Both the first exposure process and the second exposure process are exposure processes in which light is irradiated from the printing surface side. The second exposure process hardens a predetermined range by exposing from the same direction as the first exposure process with a pattern that targets a narrower area than the first exposure process. Therefore, in the second patterning process, an area including at least a portion of the first emulsion layer and at least a portion of the second emulsion layer is exposed by exposing with a second exposure pattern different from the first exposure pattern. That is, in the first emulsion layer, among the first non-exposed areas that were not hardened by the first exposure process, the areas that form the inner walls of the pattern opening 23a and the part of the second emulsion layer on one side of the first exposed areas that were hardened by the first exposure process and that form the convex portion 23d on the edge of the pattern opening 23a are hardened by the second exposure process.

[0085] Furthermore, in the second embodiment, an example was described in which convex portions 23f are formed on the periphery of a predetermined area of ​​the screen mask 20A where multiple pattern openings 23a are formed, but this is not limiting. For example, when multiple linear pattern openings 23a are arranged, convex portions 23f may be formed on both sides of each linear pattern opening 23a between adjacent pattern openings 23a. Alternatively, as shown in FIG. 9, when multiple identical patterns are formed in sections on a single screen mask 20A, convex portions 23f may be formed at positions corresponding to the boundaries of the sections. Furthermore, as shown in FIG. 8, convex portions 23f may be formed along the periphery of the screen mask 20A. For example, convex portions 23f may be formed not only on both sides in one direction but also on four sides in two different directions, for example, both sides in the X and Y directions. Alternatively, convex portions 23f may be formed to surround the periphery of the pattern opening 23a.

[0086] Although the mask film 23 has a two-layer structure consisting of a base layer 23b and a cover layer 23c, as an example, a portion of the mask film 23 may be composed of a single layer. For example, as shown in FIGS. 10 and 11, the cover layer 23c may be configured in an area including at least a portion of the pattern opening 23a, and the protrusions 23d and the surface layer of the inner wall surface of the pattern opening 23a connected to the protrusions 23d may be configured by the cover layer 23c. In this case, for example, after the base layer is exposed, a pattern opening is formed by development, and then the cover layer is coated with a different emulsion type and exposed with a second exposure pattern. In this case, by making the pattern opening of the second exposure narrower than the pattern opening of the base layer, the inner wall portion of the opening can be formed by the cover layer 23c, as shown in FIGS. 10 and 11.

[0087] Furthermore, the above-described embodiments may be combined. For example, a first convex portion 23d may be formed along the edge of the pattern opening 23a, a concave portion 23e may be formed in a predetermined area away from the edge of the pattern opening 23a, and a second convex portion 23f may be formed further outward than the concave portion 23e.

[0088] In the above embodiment, the mesh 22 is attached to the frame 21 with an adhesive, and the mask film 23 is formed over the entire opening of the frame 21. However, the present invention is not limited to this. For example, a so-called combination mesh may be used, or the mask film 23 may be formed only on a portion of the central part of the mesh 22. Furthermore, the features of the above-described different embodiments may be combined. For example, the surface of the printing side of the mask film 23 in the first embodiment may be roughened.

[0089] Although a plurality of independent pattern areas are shown, it is also possible to make the height and depth of each continuous opening different depending on the location.

[0090] The arrangement of the pattern openings 23a can be changed as appropriate depending on the print shape, and the height can also be set. In addition, the components illustrated in the above embodiments may be deleted, or the shape, structure, material, etc. of each component may be changed. Various inventions can be created by appropriately combining the multiple components disclosed in the above embodiments. By adjusting the dimensional ratio of the material, the difference in the amount of stretch between the length and width can be reduced, thereby improving printing accuracy. [Explanation of symbols]

[0091] 10...screen printing device, 12...holding member, 13...squeegee, 20...screen mask, 20a...surface, 20b...back, 21...frame, 22...mesh, 22a...warp thread, 22b...weft thread, 22c...hole portion, 23...mask film, 23a...pattern opening, 23b...base layer, 23c...cover layer, 23d...convex portion, 23e...concave portion, 23f...convex portion (second convex portion), 24...adhesive, Pa1...first emulsion hardened portion, Pa2...second emulsion hardened portion, Pb1...first unhardened portion, Pb2...second unhardened portion, Pm1...first emulsion, Pm2...second emulsion.

Claims

1. a support material having holes that allow the coating material to pass through; a mask film provided on the support material and having a pattern opening formed therein that can hold a coating material; The mask film has a convex portion formed on a part of its surface on the printing surface side, the convex portion protruding toward the printing surface side, A screen mask, wherein the surface roughness of a reference portion, which is at least a part of the surface on the printing side, is greater than the surface roughness of the projections on the printing side.

2. the mask membrane includes a base layer and a cover layer; the reference portion is formed by the base layer, The screen mask according to claim 1 , wherein the surface of the convex portion is formed by the cover layer.

3. the protrusion constitutes at least a part of an edge of the pattern opening, The screen mask according to claim 1 , wherein a recess is formed in the reference portion at a location farther from the edge than the protrusion, the recess being recessed from the printing surface more than the protrusion.

4. the reference portion forms an edge of at least a part of the pattern opening; The screen mask according to claim 1 , wherein the convex portion is formed at a position farther from the edge than the reference portion.

5. The screen mask according to claim 1 , wherein a plurality of the protrusions or the reference portions are arranged.

6. the surface roughness of the printing surface of the reference portion is Ra 0.2 μm or more and Ra 0.5 μm or less; 3. The screen mask according to claim 2, wherein the surface roughness of the printing surface of the convex portions is equal to or greater than Ra 0.01 [mu]m and less than Ra 0.2 [mu]m.

7. 3. The screen mask according to claim 2, wherein the cover layer has a thickness of 1 μm or more and 5 μm or less, the cover layer is formed along the edge of the pattern opening, and has a width of 20 μm or more and 50 μm or less.

8. 5. The screen mask according to claim 4, wherein the distance between the convex portion and the pattern opening is 10 mm or more and 100 mm or less.

Images