JPS61171390A - Mask for screen printing - Google Patents

Abstract

PURPOSE:To enable to print on a substrate having a projected part, to such an extent that even patterns in proximity to the projected parts can be printed, by a method wherein a screen fitted to a frame is subjected to forming for providing a projected part with predetermined dimensions. CONSTITUTION:A metallic mask 14 fitted to a screen frame 12 with a film 13 as a support is subjected to forming for providing a projected part 14a. With this construction, it is possible to perform screen printing even on a substrate having a projected part. The produce the screen, the mask 14 is set to a metallic mold 15 for forming the projected part, is clamped by a die 16 and a stripper plate 17, and the plate 17 is pressed against the mask by a spring 18. In this condition, the die 16 is lowered in the direction of arrow 19, whereby the metallic mask 14 is formed by a punch 20. The mask 14 thus formed is finished to be a mask for screen printing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a screen printing mask that enables printing on circuit boards having convex portions.

BACKGROUND OF THE INVENTION Screen printing has traditionally been used to form circuits on substrates by printing methods.

This screen printing is a mask in which a printed pattern is formed on a cloth screen made of silk, nylon, polyester, etc. or a stainless steel screen that is stretched tightly around a frame, and during printing, the mask is placed in close contact with the substrate surface or slightly removed. The printing paste is placed on top of the printing mask and printed by pushing it in with a squeegee, which makes it impossible to print on a substrate with convex portions.

However, as bare semiconductors have come to be mounted on ceramic substrates, there has been a demand for screen printing on a substrate 2 having a convex portion on which a semiconductor 1 is mounted as shown in FIG.

Furthermore, even when screen printing is performed on a flexible printed circuit board with a thickness of 0.2rran to 0.3rrvn, as shown in FIG. Since it protruded from the top surface of the board 3, the screen was easily damaged.

However, even if stretch molding is applied to conventional cloth screens made of silk, nylon, polyester, etc. or stainless steel mesh screens, the deformation will recover due to delayed elasticity, or the deformation will expand due to the stress applied to the screen during squeezing, making it difficult to put it into practical use. I couldn't.

However, in recent years, screens that can also be screen printed on substrates with convex portions have been developed.

Hereinafter, a case in which a substrate having convex portions is printed by a conventional method will be described with reference to the drawings.

As a conventional example, Japanese Patent Publication No. 58-2474 will be described as an example.

FIG. 7 is a process diagram for manufacturing a printing mask using a cloth screen made of silk, nylon, polyester, etc. First, as shown in FIG. Adhesive is applied to the peripheral edge 7. Next, as shown in FIG. 7, this box body 6 is attached to the screen by placing it at a desired location on the upper surface of the cloth screen 9 that is stretched without loosening on the frame 8, and then hardening the adhesive to attach the box body 6 to the screen 9. to be fixed to. After that, the screen on the inside area of the periphery of the box body 6 is cut out as shown in FIG. 7C, and then a printing pattern is formed using the emulsion 10 on the lower surface of the remaining screen as shown in FIG. 7D. The printing mask for a substrate with convex portions of the present invention can be obtained.

Problems to be Solved by the Invention However, with the above-described configuration, the overlapping portion of the opening surface 7 of the box body 6 and the bonded portion of the screen 9 must be made relatively large as shown in FIG. There were many cases where it came off due to the force caused by the jing. Therefore, the overlapping portion 6 had to be large to obtain Z. As a result, there was a problem in that printing could not be performed in the vicinity of the screen where the convex portion was formed.

In view of the above-mentioned problems, the present invention provides a screen that can print even near the convex portions by subjecting the screen to stretch molding.

Means for Solving the Problems In order to solve the above problems, the screen printing mask of the present invention is made by applying stretch molding to a desired size on a screen stretched over a frame, and taking measures to prevent deformation as necessary. It is fixed with resin etc.

Furthermore, combination masks or metal masks, which have become relatively popular in recent years, do not deform much after stretch molding, so there is no need to take measures to prevent deformation, and they can be used as they are.

Function The present invention not only enables printing on a substrate having a convex portion by performing stretch molding as described above, but also enables printing near the convex portion.

EXAMPLE A screen printing mask according to an example of the present invention will be described below.

FIG. 1 shows a longitudinal sectional view of a screen printing mask according to a first embodiment of the present invention. As shown in FIG. 1, a metal mask 14, which is stretched on a screen frame 12 using an elastic cloth made of synthetic resin, rubber, natural fiber, metal, etc., and a film-like film 13 as a support, is attached to a metal mask 14 in a portion 14a. Manufactured by stretch molding. By configuring as described above, screen printing can be performed even on a substrate having a convex portion. FIG. 2 shows an example of a method for manufacturing the screen shown in FIG. 1. The metal mask 14 shown in FIG. 2a is stretched out from the mold 15.
, and insert it between the die 16 and the stripper plate 17 and press it with the spring 18. In this state, when the die 16 is pushed down in the direction of the arrow 19 as shown in Figure b, the metal mask 14 is formed by the punch 2o. This molded metal mask 14 may be finished into a screen printing mask as shown in FIG.

In this case, since a metal mask is molded, there is no need to take any particular measures to prevent deformation after stretch molding. Furthermore, the pattern may be formed by etching or laser processing before or after the stretch molding, as long as it is not affected by the stretch molding. However, if it is too close to the overhang molding and is affected, the pattern may be molded after the overhang molding.

FIG. 3 is a longitudinal sectional view of a screen printing mask showing a second embodiment of the present invention. In the figure, a mask 22 made of silk, nylon, or polyester mesh is stretched without loosening on a screen frame 21, and in this state, stretch molding is performed on the mesh 22, and a resin 23 is further formed to prevent deformation. FIG. 4 shows an example of the manufacturing method. In FIG. 4a, the mask 22 stretched without loosening on the frame is set in the mold 24, inserted between the die 26 attached to the die holder 26 and the stripper plate 27, and pressed by the spring 28. In this state, when the die 26 is pushed down in the direction of the arrow 29 as shown in Figure b, the mask 22 is formed by the punch 3o. However, in No. 11, the shape becomes smaller due to recovery due to the delayed elasticity of the mask material, and the deformation increases during squeezing due to insufficient strength. Therefore, as shown in FIG. 4C, a resin 23 for preventing deformation is applied to the molded portion 31 of the mask 22 and hardened. However, as it is, it is not possible to coat a sufficient area due to the shape of the die 26, so it is better to remove the die 26 as shown in Figure d, and then apply the resin 23 and harden it. In the present invention, a two-component epoxy adhesive is used as the resin 23, but other adhesives may be used as long as they have the same function.

Effects of the Invention As described above, in the present invention, by subjecting a screen printing mask to stretch molding, it is possible to print a pattern on a substrate having a convex part even in the vicinity of the convex part, and at the same time, it is possible to print a pattern with a rubber hardness of 600 to 70'. If a relatively soft squeegee is used, printing can be performed without special processing such as bittering on the squeegee.

[Brief explanation of the drawing]

Figure 6 is a vertical cross-sectional view showing the method of forming the screen, Figure 6 is a vertical cross-sectional view of the substrate with protrusions, Figure 6 is for flexible screen printing. A diagram showing a conventional example of a mask and its manufacturing method 1, and FIG. 8 is a partially detailed view of the mask shown in FIG. 7. 12... Frame, 13... Net or film-like membrane, 14... Metal mask, 14a.
...Metal mask overhang processing section, 21...
...Frame, 22...Screen printing mask, 2
3...Resin for preventing deformation of the molded part. Name of agent: Patent attorney Toshio Nakao and 1 other person 44
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Mask Cow Pa J Le e4> Figure 5 Figure 6

Claims (4)

[Claims] (1) A screen printing mask that is stretched over a frame for mounting on a printing machine, subjected to stretch molding to a desired size, and then reinforced with a reinforcing agent to prevent the molded portion from deforming. . (2) The screen printing mask according to claim 1, characterized in that a resin is used as a reinforcing agent. (3) A mask for screen printing, characterized in that a metal mask for screen printing is stretched over a frame for attachment to a printing machine, and is overmolded to a desired size. (4) An elastic cloth, net, or film-like membrane made of synthetic resin, rubber, natural fiber, metal, etc. is used as a support and stretched over a support frame, and a part of the support frame is overlaid with a metal mask with overhang molding. A screen printing mask in which the periphery of the mask is adhered to a film and the overlapping film is removed.