GB2037489A

GB2037489A - Circuit Components Interconnected by Solder Layers

Info

Publication number: GB2037489A
Application number: GB7943132A
Authority: GB
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 1978-12-18
Filing date: 1979-12-14
Publication date: 1980-07-09
Also published as: CA1140680A; DE2950450A1; IT7942915A0; IT1193457B; NL7909108A; JPS5582487A; GB2037489B; JPS6149838B2

Abstract

In a printed circuit board arrangement in which leadless electronic circuit components 4a, 4b and 4c having electrodes fitted to both ends of the bodies are mounted on a printed circuit board 5, electrodes 3a and 2b and 3b and 2c of adjacent circuit components 4a, 4b and 4c are connected directly to each other through solder 20 and 21. <IMAGE>

Description

SPECIFICATION Printed Circuit Board Arrangements This invention relates to printed circuit board arrangements.

According to the present invention there is provided a printed circuit board arrangement comprising leadless electronic circuit parts having a cylindrical or prismatic body and electrodes formed on both ends of said body mounted on a printed circuit board, the electrodes of adjacent said circuit parts being connected directly to each other through solder and not through a conductive pattern.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view of one example of a leadless electronic circuit part; Figure 2 is a partially broken away crosssectional view of a prior art printed circuit board arrangement; Figure 3 is a partially broken away perspective view of the arrangement of Figure 2; and Figures 4 to 6 are partially broken away crosssectional views of first to third embodiments of printed circuit board arrangement according to the invention.

Before describing the embodiments, a prior art printed circuit board arrangement will be described with reference to Figures 1 to 3.

A known leadless electronic circuit part 4 as shown in Figure 1 has a ceramic cylindrical body 1 with metal end caps 2 and 3. The circuit part 4 is, for example, a resistor, a capacitor or a jumper.

When the circuit part 4 is a resistor, carbon film is formed on the circumferential surface of the cylindrical body 1. When the circuit 4 is a capacitor, the cylindrical body 1 is hollow, and conductive films are formed on the inner and outer circumferential surfaces of the cylindrical body 1. When the circuit part 4 is a jumper, a conductive film is formed on the circumferential surface of the cylindrical body 1, or the circuit part 4 is formed as a machined metal rod having the shape shown in Figure 1. The exposed portion of the cylindrical body 1 which is not covered by the end caps 2 and 3, is coated with insulating material.

Such circuit parts 4 are mounted on a printed circuit board 5 in the manner shown in Figures 2 and 3. First, in the mounting operation, adhesive resin 10 is applied to predetermined positions between copper patterns 6 and 7, and 8 and 9 formed on the board 5. Next, leadless electronic circuit parts 4a and 4b are mounted on the board 5 such that the central portions of the circuit parts 4a and 4b are attached to solder-resistive layers 11 and 13 with adhesive resin 10. The board 5 has a further solder-resistive layer 12. Thus, the circuit parts 4a and 4b are provisionally attached to the board 5. Next, the circuit parts 4a and 4b together with the board 5 are dipped into a solder bath, so that the end caps 2 and 3 are fixed on the patterns 6 and 8, and 7 and 9, by solder 14 and 16, and 15 and 17, respectively, as shown in Figure 3.The patterns 6 and 7 are electrically connected to each other through the circuit part 4a. The other patterns 8 and 9 are electrically connected to each other through the other circuit part 4b.

The circuit parts 4 are conveniently small, and are commonly fully automatically mounted on the board 5 by an automatic mounting apparatus.

Many such circuit parts 4 can be mounted on the board 5 at a high density.

However, when the circuit parts 4a and 4b are so mounted on the board 5 that the distance I#, shown in Figure 2, between them is too small, there is a risk that the space between them is filled with solder, and the solder 15 and 16 becomes one body, resulting in shorting of the patterns 7 and 8. In order to prevent this, the distance /, should be larger than a predetermined length. Accordingly, when numerous circuit parts 4 4 are mounted on one board 5, the density is limited.

The first embodiment will now be described with reference to Figure 4.

In this embodiment, three leadless electronic circuit parts 4a, 4b and 4c are electrically connected in series with each other. A metal end cap 2a of the first circuit part 4a is connected to a first copper pattern 18 by solder 19, a metal end cap 3a of the circuit part 4a is directly connected to to a metal end cap 2b of the second circuit part 4b, not through a conductive pattern, by solder 20, a metal end cap 3b of the circuit part 4b is directly connected to a metal end cap 2c of the third circuit part 4c, not through a conductive pattern, by a solder 21, and a metal end cap 3c of the circuit part 4c is connected to a second copper pattern 23 by solder 22. Actually, the end caps 2a, 2b, 2c, 3a, 3b and 3c are covered with solder 19 to 22 in the manner shown in Figure 3.

Thus, the series of circuit parts 4a, 4b and 4c are arranged between the patterns 18 and 23.

The circuit parts 4a, 4b and 4c can be mounted on the board 5 in the same manner as described with reference to Figures 1 to 3. In the mounting operation, adhesive resin 10 is applied at predetermined positions by a screen printing method. The circuit parts 4a, 4b and 4c are then provisionally attached to the board 5 by the adhesive resin 10. The distance 4 between the circuit parts 4a and 4b, and 4b and 4c is small in comparison with the distance /, of Figure 2, so that the spaces between the end caps 3a and 2b, and 3b and2c are filled with solder 20 and 21. For example, when the distance I, is 3.5mm, the distance 4 may be smaller than 2mm.The provisionally attached circuit parts 4a, 4b and 4c are dipped into the solder bath together with the board 5. Thus, the circuit parts 4a, 4b and 4c are fixed on the board 5 by the solder 19, 20, 21 and 22.

The second embodiment will now be described with reference to Figure 5.

Four leadless electronic circuit parts 4 are directly connected in series with each other, not through a conductive pattern, by solder 24, with their lengths in the direction shown by the arrow X in Figure 5. Two circuit parts 4 are directly connected in series with each other, not through a conductive pattern, by solder 24, with their lengths in the direction shown by the arrow Y in Figure 5. The arrow Y is orthogonal to the arrow X. The X series of circuit parts 4 are directly connected with the Y series of circuit parts 4 by solder 4. Thus, the series of six circuit parts 4 are arranged between copper patterns 25 and 26.

Cross patterns 27 extend across the circuit parts 4. The circuit parts 4 are insulated from the cross patterns 27 by the solder-resistive layer 11 and adhesive resin (not shown in Figure 5).

The third embodiment will now be described with reference to Figure 6.

Three leadless electronic circuit parts 4 are connected in the shape of a letter, with their lengths in the directions X and Y. The three circuit parts 4 are connected in series with each other through solder 32, in the direction X. Thus, copper patterns 28, 30 and 31 are electrically connected to each other. The two circuit parts 4 are connected in series with each other, with their lengths in the direction Y. Thus, the patterns 29 and 30 are electrically connected to each other.

One series of the three circuit parts 4 and another series of the two circuits parts 4 and connected to each other through the solder 32 at the pattern 30. Thus, the patterns 28 to 31 are electrically interconnected to each other through the circuit parts 4.

Leadless electronic circuit parts 4 can be arranged in an arbitrary shape with their lengths in the directions X and Y by an automatic mounting apparatus. A series circuit, a parallel circuit and a series-parallel circuit, of the same leadless electronic circuit parts, or different leadless electronic circuit parts (resistors, capacitors, and so on), can be arbitrarily designed irrespective of the arrangement of the copper patterns.

In the above embodiments, the leadless electronic circuit parts 4 are cylindrical. However, they may be of the chip type in which metal caps are fitted to both end portions of a prismatic body.

Claims

1. A printed circuit board arrangement comprising leadless electronic circuit parts having a cylindrical or prismatic body and electrodes formed on both ends of said body mounted on a printed circuit board, the electrodes of adjacent said circuit parts being connected directly to each other through solder and not through a conductive pattern.

2. An arrangement acccording to claim 1 wherein a conductive pattern is disposed under one of said circuit parts through an insulating layer.

3. An arrangement according to claim 2 wherein said insulating layer includes a solder resistive layer.

4. An arrangement according to claim 3 wherein said insulating layer includes an adhesive resin.

5. An arrangement according to claim 1 wherein the lengths of said circuit parts are arranged in directions orthogonal to each other.

6. An arrangement according to claim 1 wherein said circuits include a jumper.

7. An arrangement according to claim 1 wherein said circuit parts include a resistor.

8. An arrangement according to claim 1 wherein said circuit parts include a capacitor.

9. A printed circuit board arrangement substantially as hereinbefore described with reference to Figure 4 of the accompanying drawings.

10. A printed circuit board arrangement substantially as hereinbefore described with reference to Figure 5 of the accompanying drawings.

1 A printed circuit board arrangement substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.