JPH07283531A - Method of printing through hole circuit and printing equipment - Google Patents

Abstract

PURPOSE:To prevent conducting paste which is injected into a through hole from sticking to the back of a substratum and the surface of a table. CONSTITUTION:A screen 14 for printing is arranged on the upper surface of a plane board substratum 13 arranged on a table 11. The vicinity part of the lower part aperture 17a of a through hole 17 formed in the penetrating state in the thickness direction of the substratum 13 is arranged in the state isolated from the surface of the table 11, when conducting paste 15 permeating from above the screen 14 is stuck on the surface of the substratum 13, so as to correspond with the shape of a printing pattern formed on the screen 14 for printing. Thereby, the conducting paste 15 which permeates the through hole 17 is maintained so as not to reach the table 11.

Description

Detailed Description of the Invention

[0001]

This invention relates to a through hole circuit,
That is, the present invention relates to a printing method and a printing apparatus for forming an electric circuit having a through hole on a base material such as a PET film.

[0002]

2. Description of the Related Art A membrane switch or the like formed by forming an electric circuit on a base material such as a PET film is generally made of PET.
Circuit formation is performed by screen printing on one side of the film. In such screen printing, a printing screen obtained by closing a portion other than an electric circuit with a mask is PET.
By arranging the conductive paste, which is arranged close to the surface of the film and forms an electric circuit, through the printing screen and adhering it to the surface of the PET film, a printing pattern provided on the printing screen is formed. An electric circuit having a corresponding shape is transferred.

By the way, with the recent trend toward miniaturization and lightness of electric products, the storage space of the electric circuits inside the electric products is limited, and even in the membrane switch, only the electric circuit on one side of the PET film is applicable. The situation is becoming impossible. In order to deal with this, screen printing is performed on both sides of the PET film to increase the area where circuits can be formed. For this reason, through holes are provided in the PET film so as to penetrate in the thickness direction, and electrical circuits on both sides of the PET film are conducted through the through holes.

[0004]

Problems to be Solved by the Invention In this case, PET
By conducting screen printing on one side of the film, the conductive paste is injected into the through holes and adhered to the entire inner surface of the through holes. However,
As shown in FIG. 2, when screen printing is performed with the PET film 1 placed on the flat table 2 so as to be in close contact, the conductive paste 4 injected into the through holes 3 causes the PET film 1 to pass through. It penetrates and reaches the table 2. Then, there is an inconvenience that the back surface of the PET film 1 is soiled by getting into the gap between the table 2 and the PET film 1. Moreover, since the gap is minute, the dirt is formed over a wide range due to the penetration based on the capillary phenomenon. In the figure, reference numeral 5 is a printing screen, and 6 is a squeegee.

Further, after the printing is performed in this manner, the conductive paste 4 is attached to the table 2 as shown in FIG. 3, and the conductive paste 4 attached before the next printing is performed. Since the work of removing the paste 4 is required, there is an inconvenience that the number of work steps increases.

In order to avoid such an inconvenience, the viscosity of the conductive paste 4 injected into the through holes 3 and other printing conditions are appropriately adjusted so that only the screen printing from one side of the PET film 1 is effective. A method may be considered in which the conductive paste 4 is prevented from reaching the other surface side and the firing is performed every time screen printing of one surface is performed. in this way,
First, as shown in FIG. 4A, after screen-printing one surface of the PET film 1, the conductive paste 4 is baked and cured, and then, as shown in FIG.
The ET film 1 is inverted and screen printing is performed on the back surface. Then, the conductive paste 4 in the through holes 3 is connected for the first time by the screen printing on the back surface,
The electric circuits on both sides of the PET film 1 are electrically connected.

However, since the PET film 1 has a thickness of about 75 to 125 μm, it is extremely delicate to adjust the printing conditions so that the conductive paste 4 does not protrude from the other side of the through hole 3. If the adjustment is not properly performed, as shown in FIG. 4B, the conductive paste 4 may not be connected in the through hole 3.

The present invention has been made in view of the above circumstances, and can prevent the conductive paste injected into the through holes by screen printing from adhering to the back surface of the PET film or the surface of the table. An object of the present invention is to provide a printing method and a printing apparatus for a through hole circuit.

[0009]

In order to achieve the above-mentioned object, the through-hole printing method according to the present invention is such that a printing screen is arranged on the upper surface of a flat plate-shaped substrate arranged on a table, and When the conductive paste transmitted from above is attached to the surface of the base material according to the shape of the printing pattern applied to the printing screen, the through holes provided in the through state in the thickness direction of the base material It is characterized in that the vicinity of the lower opening is arranged apart from the table surface.

Further, the through-hole printing apparatus according to the present invention includes a table having a horizontal upper surface, and a flat plate-shaped spacer which is mounted on the upper surface of the table and in which a flat plate-shaped substrate is arranged in a close contact state. A printing screen for depositing a conductive paste, which is arranged on the base material and transmitted from above, on the surface of the base material according to the shape of the print pattern, and the spacer is in the thickness direction of the base material. It is characterized in that it has an escape hole having a larger diameter than the through hole provided in the through state at a position corresponding to each through hole.

In the above printing apparatus, the spacer is provided with a plurality of suction holes which are opened on the back surface of the base material, and suction means for connecting the suction holes to a low pressure state are connected to the suction holes. It will be effective.

[0012]

According to the method of printing a through-hole circuit of the present invention, the conductive paste transmitted from above the printing screen is formed on the surface of the flat plate-shaped substrate arranged on the table according to the shape of the printing pattern. And attached to form a through-hole circuit. At this time, since the through hole provided so as to penetrate in the thickness direction of the base material is arranged in a state in which the vicinity of the lower opening is separated from the surface of the table, the through hole passes through the through hole and comes out from the lower opening. The conductive paste projected downward is held so as not to adhere to the table.

Further, according to the through-hole printing apparatus of the present invention, when the flat plate-shaped base material is placed in close contact with the flat plate-shaped spacer attached to the upper surface of the table, the escape hole provided in the spacer is formed as a base. Since it is arranged at a position corresponding to the through hole provided in the material, the lower opening of the through hole is held in a state of being separated from the table. Then, by passing through the printing screen arranged on the upper surface of the base material and adhering the conductive paste to the surface of the base material, the conductive paste that has passed through the through holes is arranged in the escape holes, and is placed on the table. It will be held so as not to adhere.

Further, in the above printing apparatus, if the spacer is provided with a plurality of suction holes opening on the back surface of the base material and suction means is connected to the suction holes, the inside of the suction holes is moved by the operation of the suction means. It is possible to adsorb the base material to the spacer in a low pressure state and hold the through hole of the base material so as not to be displaced with respect to the escape hole of the spacer.
After printing, the suction means is stopped and the pressure in the suction holes is returned to normal pressure, so that the suction state between the base material and the spacer is easily released, and the next base material to be printed is Can be easily replaced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a printing method and a printing apparatus for a through hole circuit according to the present invention will be described below with reference to FIG. The printing method of the through-hole circuit according to the present embodiment is such that a printing screen is arranged on the surface of a base material such as a PET film, and a conductive paste that has passed through the printing screen from above is attached to the surface of the base material. This is common to the conventional printing method described above. However, the printing method of the present embodiment is different from the conventional printing method in handling the conductive paste injected into the through holes provided in the base material.

In the printing method of this embodiment, screen printing is performed on the surface of the base material while the base material is arranged in the vicinity of the lower opening of the through hole so as not to contact the table. Specifically, the printing method of this embodiment is realized by the printing device 10 shown in FIG.

As shown in FIG. 1, a printing apparatus 10 for a through-hole circuit according to this embodiment has a table 11, a spacer 12 fixed on the table 11, and a PET film arranged on the spacer 12. The printing screen 14 arranged on the upper surface of the base material 13 and the conductive paste 15 supplied to the printing screen 14 are added to the base material 13
And a squeegee 16 that allows light to pass therethrough.
The spacer 12 is made of, for example, a material having a certain degree of flatness such as a glass cloth base material epoxy resin, and has an escape hole 18 arranged at a position corresponding to all the through holes 17 provided in the base material 13. , And a plurality of suction holes 19 are provided in other portions.

The escape hole 18 is a hole that penetrates the spacer 12 in the thickness direction, and is provided so as to be arranged concentrically with the through hole 17. The diameter of the escape hole 18 is sufficiently larger than the diameter of the through hole 17 and is large enough not to reduce the flatness of the base material 13 that is placed in close contact with the upper surface of the spacer 12. Has been done.

Further, in the table 11, a plurality of suction holes 2 are provided at positions corresponding to the suction holes 19 of the spacer 12.
0 is provided so as to penetrate in the thickness direction. The intake hole 2
The one open end 20a of 0 is the suction hole 19 of the spacer 12.
To the other open end 20b, for example,
A suction means 21 such as a vacuum pump is connected via a tube 22.

The operation of the printing device 10 having the through-hole circuit configured as described above will be described below. In order to print the through-hole circuit on the surface of the base material 13 by the printing device 10, first, the spacer 12 is placed on the table 11. In this case, the suction holes 19 provided in the spacer 12 and the intake holes 20 provided in the table 11 are arranged so as to coincide with each other. Then, the spacer 12 and the table 11 are fixed to each other by an arbitrary fixing means (not shown) such as an adhesive tape so as not to be displaced.

Next, the base material 13 is placed on the surface of the spacer 12. In this case, the through holes 17 provided in the base material 13 and the escape holes 18 provided in the spacer 12 are arranged so as to coincide with each other. All the suction holes 19 provided in the spacer 12 are formed by the back surface of the base material 13 so that the upper end opening 19 is formed.
a will be blocked. Then, the suction means 21 is operated to bring the inside of the suction hole 19 into a low pressure state,
The base material 13 is closely adsorbed to the spacer 12, and the base material 1
3 and the spacer 12 are fixed so as not to be displaced.

In this state, as shown in FIG.
The conductive paste 15 is supplied to the printing screen 14 arranged above the substrate, and the squeegee 16 allows the printing screen 14 to pass therethrough, whereby the conductive paste 15 adheres to the surface of the base material 13 in a shape corresponding to the printing pattern. Will be made. Then, the conductive paste 15 injected into the through holes 17 of the base material 13 is attached to the entire inner surface of the through holes 17, and the surplus portion is made to project from below the through holes 17.

In this case, the printing apparatus 1 of this embodiment
In 0, the vicinity of the lower opening 17a of the through hole 17 is arranged in the escape hole 18 of the spacer 12, and the table 1
Since it is separated from 1, the conductive paste 15 is held so as not to adhere to the table 11. Further, since the escape hole 18 of the spacer 12 is formed to be sufficiently larger than the through hole 17, it is possible to prevent the conductive paste 15 from entering between the base material 13 and the spacer 12. , Substrate 1
The occurrence of dirt on the back surface of No. 3 is avoided.

After the printing is completed, the operation of the suction means 21 is stopped and the low pressure state in the suction holes 19 is released, so that the spacer 12 and the base material 13 are disconnected from each other. The material 13 can be easily replaced, and the work efficiency in continuously performing screen printing on a large amount of the base material 13 can be improved.

As described above, according to the through-hole circuit printing method and the printing apparatus 10 of the present embodiment, the conductive paste 15 injected into the through-hole 17 is projected from the lower opening 17a of the through-hole 17. Even if the conductive paste 15 is adhered to the table 11 or the substrate 1
It is possible to avoid soiling the back surface of the sheet 3. as a result,
When printing is performed on another base material 13, the work of removing the conductive paste 15 adhering to the table 11 becomes unnecessary, and the work efficiency can be improved. In addition, the base material 13
Since the back surface of No. 1 is not soiled, the work of removing this soil and the work of peeling off the adherence of the base material 13 in the furnace in the subsequent firing step are unnecessary, and the number of work steps can be reduced.

Further, according to the printing method of the present embodiment, since the screen printing is performed in the state where the lower opening 17a of the through hole 17 of the base material 13 is separated from the table 11, the conductivity injected into the through hole 17 is obtained. Sex paste 15
However, it is allowed to some extent to protrude from the lower opening 17a of the through hole 17. As a result, the conductive paste 15 can be supplied into the through hole 17 in an amount sufficient to cover the entire inner surface of the through hole 17, and the disconnection of the circuit in the through hole 17 can be prevented to ensure the reliability. Different circuit formation can be performed.

In the printing apparatus 10 of this embodiment, the spacer 12 made of glass cloth base epoxy resin is adopted, but the present invention is not limited to this. For example, it is made of metal whose surface is lapped. The spacer 12 may be adopted. In addition, the spacer 12 and the table 11
And the like can be applied to various through-hole circuits by fixing the spacers 12 by a simple fixing means such as an adhesive tape, and the spacer 12 can be easily replaced. It is also possible to provide the table 11 with a fixing means such as a protrusion or a frame for restricting the horizontal movement of the table 12 with respect to the table 11, and to suck the base material 13 and the spacer 12 by the suction means 21 at the same time.

[0028]

As described above in detail, in the method of printing a through-hole circuit according to the present invention, a printing screen is arranged on the upper surface of a flat plate-shaped substrate arranged on a table, and the printing screen is transmitted from above. When the conductive paste is attached to the surface of the base material according to the shape of the printing pattern applied to the printing screen, the vicinity of the lower opening of the through hole provided in the through direction in the thickness direction of the base material Since the conductive paste injected into the through holes is prevented from adhering to the table surface because it is arranged in a state of being separated from the table surface, the work of removing the adhered conductive paste is reduced and the work efficiency is improved. There is an effect that can be. Further, since a sufficient amount of the conductive paste capable of covering the entire inner surface of the through hole can be injected into the through hole, a sound through hole circuit can be formed.

The through-hole circuit printing apparatus according to the present invention includes a flat plate-shaped spacer which is attached to the upper surface of the table and has a flat-plate-shaped base material closely arranged on the upper surface thereof, and a transparent spacer which is transmitted from above the base material. And a printing screen that attaches the conductive paste to the surface of the base material according to the shape of the printing pattern, and the spacer has a clearance hole larger in diameter than the through hole of the base material at a position corresponding to each through hole. Therefore, it is possible to prevent the conductive paste that has passed through the through hole from entering between the base material and the spacer, and prevent the back surface of the base material from being contaminated. As a result, it is possible to eliminate the work of wiping off the dirt and improve the work efficiency.

Further, in the above-mentioned printing apparatus, if the spacer is provided with a plurality of suction holes opened on the back surface of the substrate and the inside of the suction holes is set to a low pressure state by the suction means, the suction means operates in addition to the above effect. By stopping the operation, it is possible to easily attach and detach the base material.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a through-hole circuit printing apparatus according to the present invention.

FIG. 2 is a vertical sectional view for explaining a conventional method of printing a through hole circuit.

3 is a vertical cross-sectional view showing a state in which a conductive paste is attached to a table by the printing method of FIG.

FIG. 4 is a vertical cross-sectional view for explaining another printing method of the conventional through-hole circuit.

[Explanation of symbols]

10 ...- Printing device, 11 ...- Table, 12 ... Spacer, 13 ... Base material, 14 ... Printing screen, 15 ...
..Conductive paste, 17 ... Through holes, 17a ...
Lower opening, 18 ... Escape hole, 19 ... Adsorption hole, 21 ...
Suction means

Claims (3)

[Claims] 1. A conductive paste (15) having a printing screen (14) arranged on the upper surface of a flat plate-shaped substrate (13) arranged on a table (11) and transmitted from above.
When attaching to the surface of the base material according to the shape of the printing pattern applied to the printing screen, the lower opening (17a) of the through hole (17) provided in a penetrating state in the thickness direction of the base material. A method for printing a through-hole circuit, characterized by arranging the vicinity in a state of being separated from the surface of the table. 2. A table having a horizontal upper surface, a flat plate-like spacer (12) attached to the upper surface of the table and closely arranging a flat plate-shaped base material on the upper surface, and arranged on the base material. A printing screen for adhering the conductive paste transmitted from above onto the surface of the base material according to the shape of the printing pattern, wherein the spacer is a through-hole provided in a penetrating state in the thickness direction of the base material. A printing apparatus for a through-hole circuit, having relief holes (18) having a larger diameter than the holes at positions corresponding to the respective through holes. 3. The spacer is provided with a plurality of suction holes (19) opening on the back surface of the base material, and the suction means (2) for maintaining a low pressure inside the suction holes.
3. The printing apparatus for a through hole circuit according to claim 2, wherein 1) is connected.