JP7804897B2 - Screen printing method and screen printing device - Google Patents

Description

The present invention relates to a screen printing method and screen printing apparatus for forming a print pattern by screen printing on the surface of a convex portion protruding from the main surface of a substrate.

Conventionally, methods have been known in which a print pattern is screen-printed onto the main surface of a substrate. Also known is a method in which, for a substrate having protrusions protruding from its main surface, a print pattern is screen-printed onto the main surface while avoiding the protrusions (see, for example, Patent Documents 1 and 2 listed below).

Japanese Patent Application Publication No. 11-139019 Japanese Patent Application Laid-Open No. 2003-211862

However, until now, there has been no established technology for forming patterns on the surfaces of protrusions protruding from the main surface of a substrate using screen printing.

The present invention aims to provide a screen printing method and screen printing device that can form a printing pattern on the surface of a substrate's protrusions protruding from its main surface by screen printing.

The screen printing method of the present invention is a screen printing method for forming a printing pattern by screen printing on the surface of a convex portion protruding from the flat upper main surface of a substrate, in which a screen having printing openings for forming the printing pattern is pressed against the convex portion with a squeegee to conform to the shape of the top of the convex portion, and the squeegee is moved while maintaining this state to push paste out from the printing openings toward the substrate and form a printing pattern on the top, and when the squeegee is positioned on the convex portion with the screen pressed downward, the lower end of the squeegee is lower than the height of the convex portion of the substrate and higher than the height of the main surface of the substrate.

The screen printing apparatus of the present invention is a screen printing apparatus that forms a printing pattern by screen printing on the surface of a convex portion protruding from the flat upper main surface of a substrate, and is equipped with a screen in which printing openings for forming the printing pattern are formed, a squeegee consisting of a plate-shaped member with corners at the lower end, and a squeegee moving means that presses the screen against the convex portion with the corners of the squeegee to conform to the shape of the top of the convex portion, and moves the squeegee while maintaining this state, thereby pushing paste from the printing openings toward the substrate and forming a printing pattern on the top, and when the squeegee is positioned on the convex portion with the screen pressed downward, the lower end of the squeegee is at a position lower than the height of the convex portion of the substrate and higher than the height of the main surface of the substrate.

According to the present invention, a printed pattern can be formed on the surface of a substrate having protrusions protruding from its main surface by screen printing.

FIG. 1 is a perspective view showing a schematic configuration of a screen printing apparatus according to an embodiment of the present invention. FIG. 1 is a side view showing a schematic configuration of a screen printing apparatus according to an embodiment of the present invention. 1 is a perspective view of a substrate on which paste is printed by a screen printing apparatus according to an embodiment of the present invention; 1 is a cross-sectional view of a portion of a screen printing apparatus according to an embodiment of the present invention; FIG. 1 is a side view showing a schematic configuration of a screen printing apparatus according to an embodiment of the present invention. 1 is a cross-sectional view of a portion of a screen printing apparatus according to an embodiment of the present invention; FIG. 1A is a partial cross-sectional view of a screen printing apparatus according to an embodiment of the present invention; FIG. 1B is a plan view of a mesh screen; FIG. 1 is a side view showing a schematic configuration of a screen printing apparatus according to an embodiment of the present invention. 1 is a cross-sectional view of a portion of a screen printing apparatus according to an embodiment of the present invention; FIG. 1A is a partial cross-sectional view of a screen printing apparatus according to an embodiment of the present invention; FIG. 1B is a plan view of a mesh screen; 1 is a perspective view of a substrate on which a print pattern is formed by a screen printing apparatus according to an embodiment of the present invention;

Embodiments of the present invention will now be described with reference to the drawings. Figures 1 and 2 show a screen printing apparatus 1 according to one embodiment of the present invention. The screen printing apparatus 1 is an apparatus that applies screen printing to a substrate KB to form a printing pattern on the surface of the substrate KB.

In this embodiment, the substrate KB to be printed by the screen printing apparatus 1 is made of a flat plate-shaped member that extends along the XY plane as a whole, as shown in Figure 3. The substrate KB has a flat upper surface (referred to as the "main surface SM") and multiple protrusions TB that protrude upward from multiple locations on the main surface SM. Each of the multiple protrusions TB has a curved surface, and the area of the curved surface near the top forms a pattern formation region PR (the area surrounded by a dashed line in Figure 3) where a pattern is formed by the screen printing apparatus 1.

In Figures 1 and 2, the screen printing apparatus 1 comprises a substrate stage 11, a screen mask 12, a print head 13, and a print head drive unit 14. For the sake of convenience in this embodiment, one direction in a horizontal plane is referred to as the left-right direction (X direction), and the up-down direction is referred to as the Z direction. Furthermore, the direction in the horizontal plane that is perpendicular to the Y direction is referred to as the front-back direction (Y direction).

In Figures 1 and 2, the substrate stage 11 has a substrate holding surface 11M with a flat upper surface. The substrate holding surface 11M is provided with a plurality of suction openings (not shown). The substrate stage 11 holds the substrate KB on the substrate holding surface 11M by suctioning it through these plurality of suction openings. The substrate stage 11 can be moved in a horizontal plane by a substrate stage movement mechanism 11K.

In Figures 1 and 2, the screen mask 12 comprises a screen holding frame 21 and a mesh screen 22. The screen holding frame 21 is made of a rectangular frame member extending along the XY plane. The mesh screen 22 is held at all four sides by the screen holding frame 21 and is flexible enough to bend in the out-of-plane direction (Z direction). A plurality of printing openings 22K are provided in the center of the mesh screen 22 for forming a printing pattern on the surface of the protruding portions TB of the substrate KB.

In Figures 1 and 2, the print head 13 includes a head base 31, a squeegee holding unit 32, a squeegee 33, a holding member 34, and a backup member 35. The print head drive unit 14 drives the print head 13 in the Z direction and the Y direction. When driven by the print head drive unit 14 in one direction (forward in this embodiment) of the Y direction (front-to-back direction), the print head 13 performs an operation called "squeegeeing" to scrape together the paste Pst supplied onto the mesh screen 22.

In Figures 1 and 2, the head base 31 of the print head 13 is the part that is directly driven by the print head drive unit 14 and has a shape that extends in the X direction as a whole. The squeegee holding unit 32 is a member that extends downward from the bottom end of the head base 31 and holds the upper end of the squeegee 33. The squeegee 33 is a generally rectangular plate-shaped member made of an elastic material such as urethane. The squeegee 33 is a member that scrapes the paste Pst on the mesh screen 22 during squeegeeing, and its lower end extends diagonally in the direction (rearward) opposite the direction of travel (forward) during squeegeeing. The lower end of the squeegee 33 forms a downwardly protruding corner 33E (Figure 2).

In Figures 1 and 2, the holding member 34 consists of a plate-shaped member extending in the X direction and is provided from the lower end of the squeegee holding portion 32 along the paste scraping surface (here, the front surface) of the squeegee 33. The backup member 35 also consists of a plate-shaped member extending in the X direction and is provided from the lower end of the squeegee holding portion 32 along the surface of the squeegee 33 opposite the paste scraping surface (here, the rear surface). In other words, the squeegee 33 is attached to the lower part of the squeegee holding portion 32, sandwiched between the holding member 34 and the backup member 35 (Figure 2). The lower end of the backup member 35 extends to the vicinity of the lower end (corner 33E) of the squeegee 33.

When using a screen printing apparatus 1 configured as described above to print a print pattern by printing paste Pst on the surface of each of the multiple protrusions TB on the substrate KB (more specifically, on the surface within the pattern formation region PR), the substrate KB is first held on the substrate holding surface 11M of the substrate stage 11. Then, the substrate stage movement mechanism 11K positions the substrate stage 11 (i.e., the substrate KB) below the screen mask 12 (Figure 2). At this time, the substrate KB is positioned so that the upper surfaces of the protrusions TB do not come into contact with the mesh screen 22, as shown in Figure 4 (the V1-V1 cross-sectional view in Figure 2). The substrate stage movement mechanism 11K also aligns the horizontal position (direction along the XY plane) of the pattern formation region PR of the substrate KB with the position of the printing openings 22K in the mesh screen 22.

Once the substrate stage 11 is positioned below the screen mask 12, the print head driver 14 positions the print head 13 behind the screen mask 12. At this time, the print head 13 is positioned so that the paste scraping surface (front surface) of the squeegee 33 is located behind the paste Pst supplied onto the mesh screen 22, and the corners 33E do not come into contact with the mesh screen 22 (Figure 2).

After positioning the print head 13 behind the screen mask 12, the print head driver 14 lowers the print head 13 (arrow A in Figure 5) to place the print head 13 in its initial position. When the print head 13 is in its initial position, the corners 33E of the squeegee 33 abut against the mesh screen 22 and press down on that portion (Figures 5, 6, and 7(a)). Here, Figure 6 is a cross-sectional view taken along line V2-V2 in Figure 5, and Figure 7(a) is a cross-sectional view taken along line V3-V3 in Figure 6.

When the print head 13 is in its initial position, the portion where the corner 33E of the squeegee 33 abuts the mesh screen 22 forms a band-shaped region (hereinafter referred to as the "squeegee abutment portion 22Q") as shown in Figure 7(b). Figure 7(b) is a plan view of the mesh screen 22 at the location shown in Figure 7(a). When the print head 13 is in its initial position, the lower end (corner 33E) of the squeegee 33 is located at a position lower than the height H1 of the protrusion TB of the substrate KB and higher than the height H2 of the main surface SM, as shown in Figure 7(a).

After positioning the print head 13 at its initial position, the print head driver 14 moves the print head 13 forward (arrow B in Figure 8). This causes the corner 33E of the squeegee 33 to move forward while remaining in contact with the mesh screen 22, scraping the paste Pst on the mesh screen 22 forward. When the corner 33E of the squeegee 33 reaches the protrusion TB of the substrate KB as the squeegee 33 moves forward, the corner 33E of the squeegee 33 elastically deforms to conform to the surface shape of the protrusion TB, pressing a portion of the mesh screen 22 against the surface of the protrusion TB (Figures 9 and 10(a)). Here, Figure 9 is a cross-sectional view taken along line V4-V4 in Figure 8, and Figure 10(a) is a cross-sectional view taken along line V5-V5 in Figure 9.

When the corners 33E of the squeegee 33 conform to the surface shape of the protrusions TB, as shown in FIG. 10(b), the portions of the squeegee abutment portion 22Q where the mesh screen 22 contacts the protrusions TB (contact portions S1) are wider in the front-to-rear direction than the portions of the mesh screen 22 on either side that are not in contact with the protrusions TB (non-contact portions S2). This is because the amount of deformation of the portions of the corners 33E of the squeegee 33 that conform to the surface shape of the protrusions TB is greater than the amount of deformation of the portions that do not conform to the surface shape of the protrusions TB (portions on both sides of the protrusions TB). Note that FIG. 10(b) is a plan view of the mesh screen 22 at the location shown in FIG. 10(a). Region SR shown in FIG. 10(b) is the region where the mesh screen 22 contacts the protrusions TB. Region SR of the mesh screen 22 contacts the protrusions TB while conforming to the surface shape of the protrusions TB. This region SR moves forward as the squeegee 33 moves forward.

As the print head 13 moves further forward, the corners 33E of the squeegee 33 pass over the printing openings 22K of the mesh screen 22, which are in close contact with the protrusions TB of the substrate KB. At this time, the corners 33E of the squeegee 33 push the paste Pst toward the substrate KB, so that the paste Pst is applied to the surface of the protrusions TB through the printing openings 22K.

The portion of the mesh screen 22 that the corner 33E of the squeegee 33 passes over attempts to return to its original state (the state before being pushed downward by the squeegee 33) due to the restoring force of the mesh screen 22 itself. As a result, after the corner 33E of the squeegee 33 has passed, the mesh screen 22 separates from the surface of the raised portion TB, resulting in what is known as plate separation. As a result, a printing pattern PPT with a shape corresponding to the shape of the printing opening 22K is formed on the surface of the raised portion TB (more specifically, on the surface of the pattern formation region PR) (Figure 11).

Here, while the squeegee 33 is aligning the corners 33E with the surface shape of the protrusions TB, it receives a large reaction force R in the direction of being pushed up (warping direction) by the corners 33E from the protrusions TB (Figure 10(a)). However, because a backup member 35 is provided on the rear surface of the squeegee 33, the entire squeegee 33 does not warp, except for localized areas such as the corners 33E. This allows the squeegee 33 to tightly adhere the mesh screen 22 to the surface of the protrusions TB over a wide area. Furthermore, because the paste Pst is pressed into the printing openings 22K with an appropriate printing pressure, the printing pattern PPT can be reliably formed over a wide area of the curved surface of the protrusions TB.

As described above, the screen printing apparatus 1 in this embodiment includes a mesh screen 22 as a screen in which printing openings 22K for forming the printing pattern PPT are formed, a squeegee 33 consisting of a plate-shaped member with corners 33E at the bottom end, and a print head drive unit 14 as a squeegee moving means that presses the mesh screen 22 against the surfaces of the protrusions TB with the corners 33E of the squeegee 33 to conform to the shape of the tops of the protrusions TB, and moves the mesh screen while maintaining this state, pushing the paste Pst out from the printing openings 22K toward the substrate KB and forming the printing pattern PPT on the tops of the protrusions TB. The screen printing apparatus 1 is configured to form a printing pattern by screen printing on the surfaces of the protrusions TB that protrude upward from the main surface SM of the substrate KB.

In the screen printing method of this embodiment using the screen printing apparatus 1 configured as described above, the mesh screen 22, which has printing openings 22K for forming the printing pattern PPT, is pressed against the surface of the protruding portion TB with the squeegee 33 so that it conforms to the shape of the apex of the protruding portion TB. While maintaining this state, the squeegee 33 is moved, forcing the paste Pst out of the printing openings 22K toward the substrate KB, forming the printing pattern PPT on the apex of the protruding portion TB. In this method, the squeegee 33 elastically deforms to conform to the shape of the protruding portion TB, forcing the mesh screen 22 to conform to the shape of the apex of the protruding portion TB, ensuring that the printing pattern PPT can be reliably formed on the curved surface of the protruding portion TB.

As described above, with the screen printing apparatus 1 (screen printing method) of this embodiment, the screen (mesh screen 22) with printing openings 22K for forming the printing pattern PPT is pressed against the protrusions TB with the squeegee 33 to conform to the shape of the tops of the protrusions TB, and by moving the squeegee 33 while maintaining this state, the paste Pst is pushed out from the printing openings 22K toward the substrate KB, forming the printing pattern PPT on the tops of the protrusions TB. This ensures that the printing pattern PPT can be reliably formed on the surfaces of the protrusions TB protruding from the main surface SM of the substrate KB.

Up to this point, we have explained the embodiments of the present invention, but the present invention is not limited to the above and various modifications are possible. For example, the shape of the convex portion TB of the substrate KB shown in the above embodiment is an example, and the shape of the convex portion TB is not necessarily limited to that shown in Figure 3 (Figure 11). Furthermore, the printing pattern PPT shown in the embodiment is an example and is not limited to that shown in Figure 10.

We provide a screen printing method and screen printing device that can form a print pattern on the surface of a substrate's protrusions protruding from its main surface by screen printing.

1 Screen printing device 14 Printing head drive unit (squeegee moving means)
22 Mesh screen (screen)
22K Printing opening 33 Squeegee 35 Backup member KB Substrate SM Main surface TB Convex portion PPT Printing pattern Pst Paste

Claims (6)

A screen printing method for forming a print pattern by screen printing on a surface of a convex portion protruding from a flat upper main surface of a substrate, the method comprising:
a screen having printing openings for forming a printing pattern formed therein is pressed against the convex portions with a squeegee to conform to the shape of the tops of the convex portions, and the squeegee is moved while maintaining this state to extrude paste from the printing openings toward the substrate, thereby forming a printing pattern on the tops;
A screen printing method, wherein when the squeegee is positioned on the convex portion while pressing the screen downward, the lower end of the squeegee is at a position lower than the height of the convex portion of the substrate and higher than the height of the main surface of the substrate. The screen printing method of claim 1, wherein the squeegee elastically deforms to conform to the shape of the convex portions, thereby causing the screen to conform to the shape of the tops of the convex portions. The screen printing method described in claim 1 or 2, wherein the squeegee is moved toward the convex portions from a state in which the main surface of the substrate and the convex portions are not in contact with the screen. A screen printing apparatus for forming a print pattern by screen printing on a surface of a convex portion protruding from a main surface, which is a flat upper surface of a substrate,
a screen having printing apertures formed therein for forming a printing pattern;
a squeegee made of a plate-like member having a corner at its lower end;
a squeegee moving means for pressing the screen against the convex portions with the corners of the squeegee to conform to the shape of the tops of the convex portions, and moving the squeegee while maintaining this state, thereby forcing the paste out from the printing openings toward the substrate and forming a printing pattern on the tops;
Equipped with
A screen printing device wherein, when the squeegee is positioned on the convex portion while pressing the screen downward, the lower end of the squeegee is at a position lower than the height of the convex portion of the substrate and higher than the height of the main surface of the substrate. The screen printing device of claim 4, further comprising a backup member that prevents the squeegee from warping when the corners of the squeegee are in contact with the screen. The screen printing device described in claim 4 or 5, wherein the squeegee is moved toward the convex portions from a state in which the main surface of the substrate and the convex portions are not in contact with the screen.