JPH03102894A - Structure of through hole and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the resistance value increase and conductivity inferiority at the through hole part formed in a flexible board by filling conductive coating, to the position that it goes over the edge parts of both ends, inside the through hole provided in the board, and printing circuit patterns so that they may cover the whole faces respectively from above the conductive coating exposed to both sides of the board. CONSTITUTION:First, a through hole 2 is formed at a specified parts of a flexible board 1. Next, conductive coating 3 is filled in this through hole 2 by screen printing. And, though circuit patterns 4 and 5 are formed on both sides of this flexible board 1 by screen printing, at this time it is so arranged that the whole faces of the conductive coating 3 are covered in addition with one part each of the circuit parts. The two layers of a layer, formed by the conductive coating 3, and a layer, formed by the conductive pattern 4 or 5, are provided between the edge part 1a of the flexible board 1 and the outside, so this part is strengthened. For this reason, oven if the flexible board 1 bend, cracks, etc., hardly occur in this part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure of a through hole for connecting circuit patterns provided on both sides of a substrate and a method of manufacturing the same.

[Conventional technology]

Conventionally, through-hole technology has been developed and put into practical use as a method for easily connecting circuit patterns provided on both sides of a board.

FIG. 9 is a side sectional view showing the structure of a conventional through hole of this kind.

As shown in the figure, the conventional through hole
Circuit patterns 101 and 103 are formed on both sides, and a through hole 107 is formed, and a conductive paint 1o5 made of silver paste is filled inside the through hole 107.
05, the upper and lower circuit patterns 101 and 103 are electrically connected.

[Problem to be solved by the invention]

By the way, this type of conventional through-hole is shown in Fig. 10 (
As shown in the enlarged view of part A shown in Fig. 9), the through hole 1
A layer made of conductive paint 105 is interposed between the edge portion 100a at the end of 07 and the outside.

However, since this layer is only one layer, its strength is low, and cracks 105a are likely to occur in the conductive paint 105 due to heat, pressure, etc. For this reason, there are problems in that the resistance value of the through-hole portion increases and poor conductivity occurs.

Particularly, when the substrate 100 is made of a flexible thin synthetic resin film (flexible substrate), the substrate 100 is easily bent, so that the crack 105a is very likely to occur.

The present invention has been made in view of the above-mentioned points, and provides a through-hole structure and a method for manufacturing the same, in which an increase in resistance value and poor conductivity are unlikely to occur in the through-hole portion even if the board is made of a flexible board. It's about doing.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has a through-hole structure in which conductive paint is filled inside a through-hole provided in a substrate to a position exceeding the edge portions at both ends of the through-hole, and is exposed on both sides of the substrate. A circuit pattern was printed on the conductive paint so as to cover the entire surface of the conductive paint.

Further, the present invention provides a through hole structure including a through hole provided in a substrate and a pad made of a conductive thin film formed on at least one surface of the substrate so as to surround the through hole. Fill the inside of the through hole of the board with conductive paint to a position beyond the edges of both ends of the through hole, and apply a circuit pattern over the conductive paint exposed on both sides of the board so as to cover the entire surface of each. Printed and configured.

Further, the present invention provides the method for manufacturing a through hole by forming a pad made of a conductive thin film on at least one surface of a flexible substrate, and inserting a punch from above the pad to form a through hole. The inside of the through-hole is filled with conductive paint to a position beyond the edges of both ends of the through-hole, and a circuit pattern is formed on the conductive paint exposed on both sides of the board so as to cover the entire surface of the conductive paint. was printed and configured.

The present invention also provides a through-hole structure in which a through-hole is formed in a predetermined portion of a circuit pattern formed on at least one surface of a substrate, and the inside of the through-hole extends beyond the edge portions of both ends of the through-hole. A conductive paint was filled and a circuit pattern was printed so as to cover the entire surface of the conductive paint exposed on the side opposite to the side on which the circuit pattern was formed.

Further, the present invention provides the method for manufacturing a through hole by forming a circuit pattern on at least one surface of a flexible substrate, and inserting a punch from above a predetermined portion of the circuit pattern to form a through hole. , fill the inside of the through hole with conductive paint to a position beyond the edges of both ends of the through hole, and fill the conductive paint exposed on the surface opposite to the surface on which the circuit pattern is formed. A circuit pattern was printed to cover the entire surface.

[Effect]

By configuring as described above, two layers of conductive material are interposed between the edge portion of the through hole formed in the flexible substrate and the outside, so this portion can be strengthened and cranks etc. are less likely to occur. .

In addition, if a pad or circuit pattern is provided in advance around at least one side of the through hole, even if the amount of conductive paint applied to the edge around the through hole on the pad side is small, the conductive paint will By being connected to this pad, etc., the layer of conductive paint on the pad side becomes thicker as a whole, making it difficult for cracks to enter.

In addition, if the configuration is such that a through hole is formed by inserting a punch from above the pad or circuit pattern provided on one side of the flexible board, the edge portion around the through hole on the side where the punch is inserted will have a gentle slope. Since it is a flat surface, it is difficult for cranks to form in the conductive paint applied on this part.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a side sectional view showing the structure of a through hole according to an embodiment of the first invention.

As shown in the figure, this through hole is made by filling the inside of a through hole 2 provided in a flexible substrate 1 with a conductive paint 3.
Circuit patterns 4 and 5 are printed on the conductive paint 3 so as to cover the entire surface thereof.

Here, the flexible substrate 1 is made of a flexible polyester film, for example.

The conductive paint 3 is made of a material such as silver paste. This conductive paint 3 is filled inside the through hole 2 and is further applied to both surfaces of the flexible substrate 1, that is, to a position beyond the edge portions 1a, 1a at both ends of the through hole 2.

The circuit patterns 4 and 5 are made of silver paste, for example, and are screen printed on the conductive paint 3 exposed on both sides of the substrate 1 so as to cover the entire surface of the conductive paint 3.

FIG. 2 is a diagram showing a manufacturing method for manufacturing this through hole.

As shown in FIGS. 2A and 2B, a through hole 2 is first formed in a predetermined portion of a flexible substrate 1. As shown in FIGS.

In this embodiment, the thickness of the flexible substrate 1 was 100 μm, and the diameter of the through hole 2 was φ0.4 mm.

Next, as shown in FIG. 2C, the through hole 2 is filled with conductive paint 3 by screen printing.

Then, circuit patterns 4 and 5 are formed on both sides of the flexible substrate 1 by screen printing, and at this time, the entire surface of the conductive paint 3 is covered by a portion of the circuit patterns 4 and 5.

This completes this through hole.

Here, FIG. 3 is an enlarged view of portion B shown in FIG. 1.

As shown in the figure, according to the through hole according to the present invention, two layers are formed between the edge portion 1a of the flexible substrate 1 and the outside: a layer formed by the conductive paint 3 and a layer formed by the conductive pattern 4 (or 5). Since two layers are provided, this part will be strengthened.

Therefore, even if the flexible substrate 1 is bent, a crank or the like is unlikely to occur in this portion.

Next, FIG. 4 is a side sectional view showing the structure of a through hole according to an embodiment of the second invention.

Note that the same members as shown in FIG. 1 are given the same reference numerals and detailed explanation thereof will be omitted.

As shown in the figure, in the case of this through hole, a through hole 2 is provided in the flexible substrate 1, and a through hole 2 is provided in the flexible substrate 1.
A pad 6 made of Tsuji conductive material is formed on one surface of the
Further, the inside of the through hole 2 is filled with a conductive paint 3, and circuit patterns 4 and 5 are printed on the conductive paint 3 so as to cover the entire surface of the conductive paint 3, respectively.

Here, pad 6 is formed on one surface of flexible substrate 1 so as to surround through hole 2 . This pad 6 is made of conductive paint such as silver paste.

Here, the conductive paint 3 is filled beyond the edge portion 1a of the through hole 2 to the position where it connects to this pad 6.

FIG. 5 is a diagram showing a manufacturing method for manufacturing this through hole.

As shown in IE (a), pads 6 are first formed on predetermined portions of the flexible substrate 1. This pad 6 is constructed by, for example, screen-printing and firing silver paste into a circular shape.

Next, as shown in FIG. 2B, a punch 50 is inserted from the side of the flexible substrate 1 on which the pad 6 is formed to form a through hole 2 in the flexible substrate 1.

FIG. 6 is an enlarged view of portion C in FIG. 5(b) when the punch 50 is inserted into the flexible substrate 1.

As shown in FIG. 5A, when the punch 50 is inserted from the side of the pad 6, the end 6a of the pad 6 on the through hole 2 side and the edge portion 1a of the flexible substrate 1 are dragged by the punch 50 and inserted into the through hole. Trying to get into the inside of 2.

As shown in FIG. 2B, when the punch 50 is pulled out, the end 6a and edge portion 1a of the pad 6 try to return in the pulling direction, but do not return completely. As a result, the inner end 6a and the edge portion 1a of the pad 6 facing the through hole 2 do not form an acute angle, but form an inclined surface that is slightly gently inclined toward the inside of the through hole 2.

Next, as shown in FIG. 5(C), the inside of the through hole 2 from which the punch 50 was pulled out is filled with conductive paint 3 from the direction of arrow D.

As shown in FIG. 1D, circuit patterns 4 and 5 are screen printed on both sides of the flexible substrate 1 so as to cover the entire surface of the conductive paint 3, respectively.

This completes this through hole.

By the way, when the conductive paint 3 is filled from the direction of arrow D, as shown in FIG. The amount of conductive paint 3 applied on 1a is rather small.

However, as in the present invention, the pad 6 is placed on this part in advance.
If this is provided, the conductive paint 3 will be connected to this node 6, so this edge portion 1a will be connected as a whole.
The layer of conductive paint 3 applied on top becomes thicker, making it difficult for a crank or the like to enter.

Further, as shown in FIG. 6(b), since the punch 50 is inserted from the side of the punch 6, the end portion 6a and the edge portion 1a
Since this is a slope that slopes gently toward the inside, cracks are unlikely to occur even if the amount of conductive paint 3 applied to this area is small. At this time, as shown in FIG. 4, the edge portion 1a of the flexible substrate 1 on the side where the pad 6 is not formed protrudes at a slightly acute angle, but the conductive paint 3 applied on this side ' Since it is the side to be filled with the wt paint 3, the layer is thick and therefore cracks are less likely to occur.

Note that the pads 6 may be provided on both sides of the through hole 2.

Next, FIG. 7 is a side sectional view showing the structure of a through hole according to an embodiment of the third invention.

Note that the same members as shown in FIG. 1 are given the same reference numerals and detailed explanation thereof will be omitted.

As shown in the figure, in the case of this through hole, a through hole 2 is formed on the circuit pattern 5' formed on one side of the flexible substrate 1, and the inside of the through hole 2 is filled with conductive paint 3. Furthermore, a circuit pattern 4 is printed so as to cover the entire surface of the conductive paint 3 exposed on the surface opposite to the surface on which the circuit pattern 5' is formed.

Here, the conductive paint 3 is filled over both the upper and lower edge portions 1a of the through hole 2. And circuit pattern 5'
The conductive paint 3 is connected to.

FIG. 8 is a diagram showing a method of manufacturing this through hole.

As shown in FIG. 5A, first, a desired circuit pattern 5' is formed on one surface of the flexible substrate 1 by screen printing.

Next, as shown in FIG. 2B, a punch 50 is inserted into the flexible substrate 1 from the side on which the circuit pattern 5' is formed to form a through hole 2 in the flexible substrate 1.

If the punch 50 is inserted in this way, the circuit pattern 5' around the through hole 2 on the entry side will be removed as shown in FIG.
The end and edge portion 1a are not at an acute angle, and there is a slight through hole 2.
It is a slope that slopes gently towards the inside of the area.

Next, as shown in FIG. 8(C), the inside of the through hole 2 from which the punch 50 was pulled out is filled with the conductive paint 3 from the direction of the arrow E.

Next, as shown in FIG. 4(d), a circuit pattern 4 is applied so as to cover the entire surface of the conductive paint 3 exposed on the surface of the flexible substrate 1 opposite to the surface on which the circuit pattern 5' is formed. Screen print.

This completes this through hole.

Even with this configuration, since the upper portion of the through hole shown in FIG. 7 has a two-layer structure, cranks and the like are unlikely to occur. Also, the edge part 1a of the lower part of the through hole
Since the end portion 5a' of the circuit pattern 5' is a gently sloped surface as in the case of the second invention, cranks and the like are unlikely to occur in this portion as well.

Note that the above inventions may be applied not only to flexible substrates but also to rigid substrates that do not have flexibility.

〔Effect of the invention〕

As explained in detail above, according to the through-hole structure and manufacturing method thereof according to the present invention, two layers of conductive material are interposed between the edge portion of the through-hole formed in the flexible substrate and the outside. Therefore, strengthen that part,
This has an excellent effect in that the through-hole portion is less prone to increase in resistance value and poor conductivity.

In addition, if a pad is provided in advance around at least one side of the through hole, even if the amount of the conductive Km material applied to the edge portion around the through hole on the pad side is small, the conductive paint will be absorbed by the pad. As a result, the conductive paint layer on the pad side becomes thicker as a whole, which has an excellent effect of being less prone to cracks.

In addition, if a through hole is formed by inserting the punch 50 from above the pad or circuit pattern provided on one side of the flexible board, the edge portion around the through hole on the side into which it is inserted becomes a gently sloped surface. Therefore, it has an excellent effect that cracks are less likely to occur in the conductive paint 3 applied to this part.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the structure of a through hole according to an embodiment of the first invention, FIG. 2 is a diagram showing a manufacturing method for manufacturing this through hole, and FIG. 3 is similar to FIG. 1. Show B
4 is a side sectional view showing the structure of a through hole according to an embodiment of the second invention; FIG. 5 is a diagram showing a manufacturing method for manufacturing this through hole; FIG. The figure is an enlarged view of part C in FIG. 5(b) when the punch 50 is inserted into the flexible substrate 1, and FIG. 7 is a diagram showing the structure of a through hole according to an embodiment of the third invention. 8 is a side sectional view showing the method of manufacturing this through hole, FIG. 9 is a side sectional view showing the structure of a conventional through hole, and FIG. 10 is an enlarged view of part A shown in FIG. 9. be. In the figure, 1... Flexible board, 1a... Edge portion, 2... Through hole, 3... Conductive paint, 4, 5.5'
. . . circuit pattern, 6 . . . pad, 50 . . . punch.

Claims (5)

[Claims] (1) Fill the inside of the through-hole provided in the board with conductive paint to a position beyond the edge portions at both ends of the through-hole, and also fill the entire surface of the conductive paint from above the conductive paint exposed on both sides of the board. A through-hole structure characterized by a circuit pattern printed over it. (2) A through hole provided in a substrate, and a pad made of a conductive thin film formed on at least one surface of the substrate so as to surround the through hole; A conductive paint is filled inside the through-hole to a position exceeding the edge portions at both ends, and a circuit pattern is printed on the conductive paint exposed on both sides of the board so as to cover the entire surface thereof. Through-hole structure featuring (3) A pad made of a conductive thin film is formed on at least one surface of a flexible substrate, a punch is inserted from above the pad to form a through hole, and a through hole is formed inside the through hole. , the through-hole is filled with conductive paint up to a point beyond the edge portions at both ends, and a circuit pattern is printed on top of the conductive paint exposed on both sides of the board so as to cover the entire surface of each. A method for manufacturing through-holes. (4) Forming a through hole in a predetermined portion of the circuit pattern formed on at least one surface of the board, filling the inside of the through hole with conductive paint to a position beyond the edge portions of both ends of the through hole, and . A through-hole structure, characterized in that a circuit pattern is printed so as to cover the entire surface of the conductive paint exposed on the surface opposite to the surface on which the circuit pattern is formed. (5) Forming a circuit pattern on at least one side of a flexible substrate, punching a punch from above a predetermined portion of the circuit pattern to form a through hole, and forming a through hole inside the through hole. Then, fill the through hole with conductive paint to a point beyond the edge portions at both ends, and further cover the entire surface of the conductive paint exposed on the side opposite to the side on which the circuit pattern is formed. , a method for manufacturing a through hole characterized by printing a circuit pattern.