JPH0631734Y2 - Printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a printed wiring board having a printed wiring pattern for large current and a printed wiring pattern for small signal on a substrate surface, for example.

(Prior Art) FIG. 2 is a circuit diagram of a large current control element and a small signal control element. In FIG. 2, 2 and 4 are transistors as a large current control element, 6 is a transistor as a small signal control element, and 8 is an emitter resistance.

FIG. 3 is a plan view of a printed wiring board on which the circuit element of FIG. 2 is mounted. FIG. 3 shows a printed wiring pattern 14, 16 for mounting the large current control transistors 2, 4 and a printed wiring pattern for mounting the small signal control transistor 6 on the substrate surface 12 of the printed wiring board 10. 18, a small-signal printed wiring pattern 20 serving as an emitter resistor 8 and a large-current printed wiring pattern 22 serving as a power supply line have the same thickness and a corresponding pattern width and shape by a known printing wiring technique. Has been formed.

(Problems to be solved by the invention) By the way, when the thickness of each printed wiring pattern is t, the pattern width of the small signal printed wiring pattern 20 is W1, and the pattern width of the large current printed wiring pattern 22 is W2,
The cross-sectional area S1 of the small signal printed wiring pattern 20 is W1 × t
The cross-sectional area S2 of the large-current printed wiring pattern 22 is represented by W2 × t.

In this case, the small-signal printed wiring pattern 20 has a cross-sectional area S1 corresponding to the resistance value of the emitter resistor 8, while the large-current printed wiring pattern 22 has a cross-sectional area S2 corresponding to a DC resistance value of zero. The size relationship of the pattern widths is W2 >> W1, and the pattern width W2 of the large-current printed wiring pattern 22 is inevitably large.
As shown in the figure, it occupies most of the area on the substrate surface 12.

Therefore, the printed wiring board 10 of the conventional example has a problem that the mounting density of electronic components on the surface of the board becomes extremely low.

The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to increase the mounting density of electronic components by reducing the area occupied by the large current printed wiring pattern on the substrate surface.

(Means for Solving the Problem) In order to achieve such an object, in the printed wiring board of the present invention, a first wiring pattern and a second wiring pattern having a resistance value smaller than that of the first wiring pattern are provided. And the wiring pattern is provided on the substrate surface, and the width of the second wiring pattern is made substantially equal to the width of the first wiring pattern by increasing the thickness dimension of the second wiring pattern. I am trying.

(Operation) According to the above configuration, since the width of the second wiring pattern having a small resistance value is also substantially equal to the width of the first wiring pattern, the second wiring pattern is occupied in the printed wiring board. The area is reduced, and the mounting density of electronic components on the printed wiring board can be increased accordingly.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing a cross section of a main part of a printed wiring board according to an embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 3 according to the conventional example are denoted by the same reference numerals, and the description of the parts associated with the same reference numerals is omitted.

In the printed wiring board 23 of this embodiment, its board surface 1
2, the product of the groove width, which is substantially equal to the pattern width W1 of the small signal printed wiring pattern 20 as the first wiring pattern, and this groove width, is the large current printed wiring as the second wiring pattern in FIG. A feature is that a groove 24 having a groove depth d that is substantially equal to the cross-sectional area W2 × t of the pattern 22 is formed, and the large current printed wiring pattern 22 is formed in the groove 24. ing.

The large current printed wiring pattern 22 is, for example, A
It is obtained by pouring a conductive paste such as g-Pd into the groove 24 and then firing it.

The rest of the configuration of this embodiment is similar to that of the conventional example.

In the printed wiring board 23 of the present embodiment having the above configuration, the large current printed wiring pattern 22 is formed in the groove 24 having a cross-sectional area of a size such that the DC resistance value is substantially zero. And the groove width of the groove 24 is made substantially equal to the pattern width of the small signal printed wiring pattern,
The area occupied by the large-current printed wiring pattern 22 on the printed wiring board 23 is significantly reduced. As a result, the mounting density of electronic components on the printed wiring board 23 can be increased. Further, when the large current printed wiring pattern 22 is formed to have a large groove width in a structure having a shallow groove depth, bulges and protrusions of the pattern are likely to occur, which makes it difficult for the cross-sectional area to be constant. According to the method, since the pattern is unlikely to rise or protrude, the cross-sectional area is maintained at a predetermined value, whereby the large-current printed wiring pattern 22 having a stable resistance value can be obtained.

As the wiring board, the printed wiring pattern 2 for large current is used.
Since the groove width of 2 can be made small, the space between the patterns can be widened when the space of the wiring substrate is made constant, which improves the frequency characteristic and particularly the high frequency characteristic.

Further, since the large current printed wiring pattern 22 and the small signal printed wiring pattern 20 have substantially the same pattern width, the pattern design of this wiring board can be easily performed with a simple wiring pattern, and the wiring board can be easily designed. The operation of mounting the circuit element on the device can be easily performed by a simple operation.

(Effect of the Invention) As is apparent from the above description, according to the present invention,
For example, it is possible to increase the mounting density of electronic components by reducing the area occupied by the second wiring pattern formed for a large current on the substrate surface, and to reduce the width of the second wiring pattern. Since the swelling of the pattern is unlikely to occur, the cross-sectional area thereof is maintained at a predetermined value, whereby a wiring pattern having a stable resistance value can be obtained.

Further, according to the present invention, since the width of the second wiring pattern can be made small, the space between the patterns can be widened when the space of the wiring board is made constant, which allows the frequency characteristics of the wiring board, especially high frequency. A product having improved characteristics can be obtained.

In addition, since the first wiring pattern and the second wiring pattern have substantially the same width, the pattern design of the entire wiring board can be easily performed with a simple structure, and the circuit element for the wiring board can be provided. The mounting operation of can be easily performed by a simple operation.

[Brief description of drawings]

FIG. 1 is a sectional perspective view of an essential part of a printed wiring board according to an embodiment of the present invention. FIG. 2 is a circuit diagram of a circuit element mounted on a printed wiring board,
FIG. 3 is a plan view of a printed wiring board according to a conventional example. 10 ... Printed wiring board, 12 ... Board surface, 20 ... Small signal printed wiring pattern, 22 ... Large current printed wiring pattern.

Claims (1)

[Scope of utility model registration request] 1. A first wiring pattern and a second wiring pattern having a resistance value smaller than that of the first wiring pattern are provided on a substrate surface, and a thickness dimension of the second wiring pattern is large. As a result, the printed wiring board is characterized in that the width of the second wiring pattern is made substantially equal to the width of the first wiring pattern.