JPH10303520A - Printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the manufacturing performance and reduce a cost effectively with a simple construction by a method wherein conductive lands of which a large current circuit is composed are connected to each other with wire-type connection conductors which are bonded to the conductive lands by ultrasonic bonding. SOLUTION: Connection conductors 4 consisting of aluminum wires or copper wires are connected to conductive lands 3a, 3b and 3c of which a large current circuit is composed by ultrasonic bonding. The ultrasonic bonding is practiced in such a manner that an aluminum wire 4A, for instance, is paid off from a spool and inserted into the insertion hole of a wedge tool 5 and set so as to have its tip part positioned in a groove, the wedge tool is positioned on the conductive land 3a and the wedge tool is pressed against the land 3a in this state so as to compress the aluminum wire 4A on the land 3a with a proper load and, at the same time, an ultrasonic wave is applied to a wedge main part to connect the aluminum wire 4A to the conductive land 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board, and more particularly to an improvement in a connection structure using connection conductors between conductive lands constituting a large current circuit in a printed wiring board having a large current circuit.

[0002]

2. Description of the Related Art In general, electronic control devices and light control devices for automobiles have a built-in printed wiring board having various circuits including a control circuit having a small current capacity and a control circuit having a large current capacity. In particular, in a large current circuit having a large current capacity, a desired current capacity is secured by setting the width (pattern area), the thickness, and the number of pattern layers of the printed wiring network large.

However, in this structure, in order to form a large current circuit having a large current capacity, the width of the wiring network must be increased, and the number of times of printing must be increased in order to secure the thickness. Therefore, there is a problem that the manufacturing operation becomes extremely complicated and the cost increases.

[0004]

Therefore, conventionally, in order to solve such a problem, a large current circuit portion is constituted by a bus bar or a boss bar (connection conductor) made of a metal plate such as copper. A structure has been proposed in which a connection conductor is incorporated before forming a wiring network on a substrate, or after the formation of the wiring network, the connection conductor is soldered to a conductive land constituting a large current circuit.

[0005] Specifically, for example, it is configured as shown in FIG. In FIG. 1, a printed wiring board 1 includes a substrate 2 made of, for example, an insulating member, a wiring network appropriately formed on the substrate 2, and a plurality of conductive lands 3a and 3b formed on appropriate portions of the wiring network. And this conductive land 3
a, 3b,... and a connection conductor 4 soldered to the conductive lands 3a, 3b forming a large current circuit.

According to this configuration, an appropriate size can be selected according to the current capacity by separately providing the connection conductor 4, so that troubles such as heat generation of the printed wiring board 1 due to the flowing current can be solved. On the other hand, it is difficult to solder the connection conductor 4 to the conductive lands 3a and 3b, and the size of the connection conductor 4 must be set to the size of the largest current capacity in order to have versatility. In addition, the size of the substrate becomes unnecessarily large, and the cost increases.

If the connection conductor 4 having a current capacity corresponding to the type of the printed wiring board is prepared, the board size can be set to an appropriate size depending on the model. However, there is still a problem that the production is complicated and the cost is increased, though not so much as the decrease in the productivity due to the increase in the number of printings for securing the thickness and the thickness.

Therefore, an object of the present invention is to provide a printed wiring board which can remarkably improve the manufacturability with a simple structure and can effectively reduce the cost.

[0009]

SUMMARY OF THE INVENTION Accordingly, in order to achieve the above-mentioned object, the present invention has a conductive land for connecting various components to an appropriate portion of a printed wiring network formed on a substrate, and A second aspect of the present invention is characterized in that, in a printed wiring board in which conductive lands constituting a current circuit are connected by connection conductors, the connection conductors are formed linearly and connected to the conductive lands by ultrasonic bonding. In the invention, the connection conductor is constituted by an aluminum wire or a copper wire.

A third invention of the present invention is characterized in that an aluminum wire or a copper wire is ultrasonically bonded to a conductive land constituting the large current circuit by using a wedge tool. A connector is provided on at least one side edge of the substrate, and a terminal of the connector and a conductive land formed in the vicinity of the terminal are connected by ultrasonic bonding with a connection conductor made of a wire.

[0011]

Next, an embodiment of a printed wiring board according to the present invention will be described with reference to FIG.
The same parts as those in the conventional example shown in FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. In the figure, a feature of the present invention is that a connection conductor 4A made of an aluminum wire or a copper wire is connected to the conductive lands 3a, 3b, 3c constituting a large current circuit by ultrasonic bonding.

In this ultrasonic bonding, for example, FIG.
The wedge tool 5 shown in FIG. The wedge tool 5 is formed of, for example, a ceramic material, a steel material, or the like, and has a column-shaped main body 6, a semicircular groove 7 formed in the center of the bottom surface of the main body 6, and The projection 8 includes an integrally formed protrusion 8 and an insertion hole 8 a for the connection conductor 4 </ b> A formed in the protrusion 8. An ultrasonic horn (not shown) is coupled to an upper portion of the main body 6 so that ultrasonic energy is applied to the main body 6.

The conductive lands 3a of the connecting conductor 4A made of an aluminum wire or a copper wire using the wedge tool 5 are used.
A bonding method (stitch bonding method) for bonding to 3b and 3c will be described. First, for example, an aluminum wire 4 </ b> A is drawn out of a spool (not shown) through the wedge tool 5 and inserted into the insertion hole 8 a, and the wedge tool 5 is set so that the tip end is located in the groove 7. Then, the wedge tool 5 is positioned on the conductive land 3a. In this state, the wedge tool 5 is pressed so that the aluminum wire 4A is pressed against the conductive land 3a with an appropriate load, and at the same time, ultrasonic waves are applied to the wedge body 6 so that the aluminum wire 4A is superposed on the conductive land 3a. They are connected by sonic bonding. After the connection, the wedge tool 5 is moved to the conductive land 3b so as to draw an arc. With this movement, the form between the conductive lands of the aluminum wire 4A becomes substantially arc-shaped. Hereinafter, the same operation is performed on the conductive lands 3b and 3c. After the bonding to the conductive land 3c is completed, the aluminum wire 4A is pulled by moving the wedge tool 5 in a state where the feeding from the spool is stopped. In addition, this cutting can also be performed using the edge of the wedge body 6.

According to this embodiment, the connection of the connection conductor 4A made of an aluminum wire or a copper wire to the conductive lands 3a, 3b, 3c constituting the large current circuit is performed by ultrasonic bonding using the wedge tool 5. The connection can be made, for example, in 0.5 seconds or less per conductive land. For this reason, work efficiency can be remarkably improved as compared with the conventional bus bar soldering.

Further, the current capacity can be easily adjusted by changing the number of parallel wirings of the connecting conductor 4A made of an aluminum wire or a copper wire according to the capacity. Is used, even if the capacity is large, it is possible to cope with a small number of parallel wires.

In particular, if the connecting conductor 4A made of a copper wire is used instead of the aluminum wire, the current capacity can be set advantageously even with the same diameter as the aluminum wire.

Furthermore, even if the wiring pattern of the printed wiring board 1A is changed, the width of the bus bar,
It does not require a lot of man-hours to change the thickness, length, etc.
Can be easily and easily handled.

FIG. 3 shows another embodiment of the present invention, which is basically the same as the above embodiment. The difference is that a connector 9 having a plurality of terminals 9A is arranged on the side edge of the printed wiring board 1B, and the plurality of conductive lands 3A and the terminals 9A arranged in the vicinity of the terminals 9A are appropriately connected to an aluminum wire. Ultrasonic bonding with a connecting conductor such as this.

According to this embodiment, the terminal 9 of the connector 9
When a large current circuit is included in A, the terminal 9A and the conductive land 3A are bonded by ultrasonic bonding of the connection conductor.
Electrical connection with the device can be made easily and easily, workability can be improved, and changes in wiring patterns and the like can be appropriately dealt with.

It should be noted that the present invention is not limited to the above-described embodiment. For example, stitch bonding is preferable for bonding the connection conductor to the plurality of conductive lands, but a connection method other than the stitch method can be adopted. It is.
The tool used for bonding may be a wedge-type tool or a cylindrical tool having a through hole at the center.
The substrate may be in any other suitable shape than square. Further, the number of connection points of the connection conductors to the conductive lands can be appropriately increased or decreased according to the circuit network of the large current circuit.

[0021]

As described above, according to the present invention, the conventional busbar is used because the connection of the connection conductor made of an aluminum wire or a copper wire to the conductive land constituting the large current circuit is performed by ultrasonic bonding. Can be connected in a shorter time as compared with a method of soldering, and work efficiency can be remarkably improved.

In addition, even if the wiring pattern of the printed wiring board is frequently changed, it can be easily handled only by moving the bonding tool between predetermined conductive lands. The inconvenience that the work becomes complicated due to such changes can be solved.

In particular, when the connection conductor is ultrasonically bonded between a plurality of conductive lands, workability and cost can be effectively improved by applying a stitch bonding method using a wedge tool.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a printed wiring board according to the present invention.

2A and 2B show a wedge tool according to the present invention, wherein FIG. 2A is a side sectional view of a main part, and FIG. 2B is a front view of the main part.

FIG. 3 is a schematic perspective view showing another embodiment of the printed wiring board according to the present invention.

FIG. 4 is a schematic perspective view of a conventional printed wiring board.

[Explanation of symbols]

 1A, 1B Printed wiring board 2 Board 3a, 3b, 3c, 3A Conductive land 4A Connection conductor 5 Bonding tool (wedge tool) 6 Main body 7 Groove 8a Insertion hole 9 Connector 9A Terminal

Claims (4)

[Claims] 1. A printed wiring board having conductive lands for connecting various components at an appropriate portion of a printed wiring network formed on a substrate and connecting conductive lands forming a large current circuit with connection conductors. A printed wiring board, wherein the connection conductor is formed in a linear shape and connected to the conductive land by ultrasonic bonding. 2. The printed wiring board according to claim 1, wherein said connection conductor is an aluminum wire or a copper wire. 3. The printed wiring board according to claim 1, wherein an aluminum wire or a copper wire is ultrasonically bonded to a conductive land constituting the large current circuit using a wedge tool. 4. A connector is provided on at least one side edge of the board, and a terminal of the connector and a conductive land formed in the vicinity of the terminal are connected by ultrasonic bonding with a connection conductor made of a wire. The printed wiring board according to claim 1, wherein: