JPH04261097A - Multilayer printed board - Google Patents

Abstract

PURPOSE:To prevent the generation of a radio interference and to contrive the improvement of the heat dissipation property of a multilayer printed board by a method wherein circuit patterns, which respectively have signal lines, are respectively formed on internal layers and pads and lands for component mounting use, through hole lands for component connection use and solid patterns for power supply or ground use are respectively formed on external layers. CONSTITUTION:Circuit patterns 13, which respectively have signal lines 12, are respectively formed on second and third layers 3 and 4, which are internal layers, in the state of use. Solid patterns 10 for ground use are respectively formed on first and fourth layers 2 and 5, which are external layers, in such a way as to cover these layers 3 and 4. Accordingly, a radio interference wave, which is generated from the lines 12 or intrudes from the outside, is cut off by the constant-potential solid patterns 10 for ground use and a radio interference is not exerted. Moreover, as the solid patterns 10 are respectively formed on the external layers, a copper residual ratio in the surface of a multilayer printed board is increased and the heat dissipation property of the board is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed circuit board in which a plurality of printed circuit boards are laminated.

0002

2. Description of the Related Art A multilayer printed circuit board is a laminate formed by laminating multiple layers of printed circuit boards each having a circuit pattern. In a conventional multilayer printed circuit board, a circuit pattern having a signal line is formed on the outer layer, and a circuit pattern having a power supply line and a ground is formed on the inner layer. This is because checking and correction become easier by forming a circuit pattern having signal lines on the outer layer.

However, in such a multilayer printed circuit board having a signal line circuit pattern on the outer layer, radio interference waves generated from the signal lines are directly emitted into the space, causing interference with equipment such as radios and televisions. On the other hand, there is a problem in that radio interference waves from the outside enter the signal line and cause interference such as noise.

[0004] Furthermore, when a signal line is formed on the outer layer, there is a problem in that the copper residual rate on the surface is low and heat dissipation is poor. Furthermore, since pads and lands for mounting components are formed on the outer layer, the space for forming signal lines is reduced.
There was a problem that the wiring efficiency of the pattern was low.

[0005]

[Problems to be Solved by the Invention] The present invention has been made to solve the above problems, and its purpose is to obtain a multilayer printed circuit board that prevents radio wave interference, has good heat dissipation, and has good wiring efficiency. It is said that

[0006]

[Means for Solving the Problems] The present invention provides the following multilayer printed circuit board.

(1) In a multilayer printed circuit board in which printed circuit boards having circuit patterns are laminated, a circuit pattern having a signal line is formed on the inner layer, and pads and lands for mounting components, through-hole lands for connection, and A multilayer printed circuit board with a solid pattern for power supply or ground.

(2) The multilayer printed circuit board according to the above (1), which is provided with a plating layer that electrically connects the power supply or ground solid patterns formed on both outer layers at the periphery.

(3) The surface of the solid pattern for power supply or ground formed on the outer layer is coated with a radio wave absorber (
The multilayer printed circuit board according to 1) or (2).

The solid pattern for power supply or ground formed on the outer layer can be a solid pattern for one or both of the power supply and ground. In the present invention, a solid pattern is a pattern formed by a conductor layer over a wide range of a substrate.

[0011]

[Operation] In the multilayer printed circuit board of the present invention, components are mounted on pads and lands for mounting components on the outer layer, a power source is connected to the power supply pattern, and the ground pattern is grounded as necessary.

In use, the signal lines are formed on the inner layer, and a solid pattern for power supply or ground is formed on the outer layer to cover them, so that radio interference waves generated from the signal lines or entering from the outside are prevented. is blocked by a constant-potential power source or a solid ground pattern, and does not cause radio interference.

Furthermore, since a solid pattern for power supply or ground is formed on the outer layer, the copper residual rate on the surface is increased and heat dissipation is improved. Furthermore, since there are no pads or lands for mounting components on the inner layer where the signal lines are formed, the wiring density can be increased.

[0014] By electrically connecting the power supply or ground solid pattern on the outer layer with a plating layer or covering it with a radio wave absorber, the ability to prevent radio wave interference is further improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a multilayer printed circuit board according to an embodiment, and FIG. 2 is a cross-sectional view taken along line AA.

In the figure, 1 is a multilayer printed circuit board, in which a first layer 2, a second layer 3, a third layer 4, and a fourth layer 5 of printed circuit boards are laminated with prepreg sandwiched therebetween and cured.
The prepreg is omitted from the illustration. Of these, the first layer 2 and the fourth layer 5 are outer layers, and the second layer 3 and third layer 4 are inner layers.

On the first layer 2, which is the outer layer, a pad 6 for mounting components, a land 7 for mounting components, a through-hole land 8 for connection, a pattern 9 for power supply, and a solid pattern 10 for grounding are formed. There is. The surface of the ground solid pattern 10 is covered with a radio wave absorber 11.

The second layer 3 and the third layer 4, which are inner layers, include:
A circuit pattern 13 having a signal line 12 and a power supply through hole 14 are formed. The second layer 3 is the first
A circuit pattern 13 having a signal line 12 on the surface of the third layer 4 and the fourth layer 5 is formed on the surface of the layer 2 side.

The fourth layer 5, which is the outer layer, has an outward facing surface (FIG.
(lower surface), pad 6 for component mounting similar to the first layer 2, land 7 for component mounting, through-hole land 8 for connection, power supply pattern 9, and ground solid pattern 10
is formed.

As the radio wave absorber 11, a mixture of paint and a magnetic material such as copper paste or ferrite powder may be used, but the present invention is not limited thereto.

In the multilayer printed circuit board 1 configured as described above, components are mounted on the component mounting pads 6 and lands 7 of the outer first layer 2 and/or fourth layer 5, and the power supply pattern is A power supply is connected to 9, and a grounding solid pattern 10 is grounded as necessary.

In use, the circuit pattern 13 having the signal line 12 is formed on the second layer 3 and the third layer 4, which are the inner layers, and the ground solid pattern 10 is formed on the outer layer so as to cover them. Since they are formed in the first layer 2 and the fourth layer 5, radio interference waves generated from the signal line 12 or entering from the outside are blocked by the constant potential ground solid pattern 10 and do not cause radio interference.

Furthermore, since the grounding solid pattern 10 is formed on the outer layer, the copper residual rate on the surface is increased and heat dissipation is improved. Furthermore, since there are no pads 6 or lands 7 for mounting components on the inner layer forming the signal line 12, the wiring density can be increased.

By covering the grounding solid pattern 10 of the outer layer with the radio wave absorber 11, the prevention of radio wave interference is further improved.

FIGS. 3 and 4 are perspective views showing multilayer printed circuit boards of other embodiments, and in both cases, pads 6 for mounting components, lands 7, and through-hole lands for connection are provided on the surface of the first layer 2. 8. A power supply pattern 9 is provided,
These illustrations are omitted, and the ground solid pattern 10
Only the following are shown.

In the embodiment shown in FIG. 3, a plating layer 15 is formed on the side surface of the laminated first layer 2 to fourth layer 5.
And the grounding solid pattern 10 on the outside of the fourth layer 5 is electrically connected. In the embodiment shown in FIG. 4, a through hole 16 is formed along the periphery, and a plating layer 1 is formed on the inner surface of the through hole 16.
5 is formed to electrically connect the grounding solid pattern 10 on the outside of the first layer 2 and the fourth layer 5.

In the multilayer printed circuit board 1 configured as described above, the plating layer 15 electrically connects the grounding solid pattern 10 on the outside of the first layer 2 and the fourth layer 5, so that radio interference waves are prevented. Increased absorbency. By covering the plating layer 15 with the radio wave absorber 11, the radio wave interference prevention property is further improved.

In the above embodiment, the solid ground pattern 10 was formed on the first layer 2 and the fourth layer 5, which are the outer layers, and the power pattern 9 was not formed as a solid pattern. It may be a solid pattern, or both the power supply pattern and the ground pattern may be solid patterns. In the latter case, the plating layers connect power supply patterns or ground patterns.

[0029]

According to the present invention, a circuit pattern having signal lines is formed on the inner layer of a multilayer printed circuit board, and pads for mounting components, lands, through-hole lands for connection, and a flat surface for power supply or ground are formed on the outer layer. Since the pattern is formed, a multilayer printed circuit board that prevents radio interference, has good heat dissipation, and has high wiring efficiency can be obtained. Furthermore, those in which the solid pattern for power or ground on the outer layer is electrically connected with a plating layer, and those covered with a radio wave absorber have even higher radio wave interference prevention properties.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a multilayer printed circuit board according to an embodiment.

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 is a perspective view of another embodiment.

FIG. 4 is a perspective view of another embodiment.

[Explanation of symbols]

1 Multilayer printed circuit board 2 First layer 3 Second layer 4 3rd layer 5 4th layer 6 Pad 7 Land 8 Through hole land 9 Power supply pattern 10 Solid pattern for ground 11 Radio wave absorber 12 Signal line 13 Circuit pattern 14 Power supply through hole 15 Plating layer 16 Through hole

Claims (3)

[Claims] Claim 1: A multilayer printed circuit board in which printed circuit boards having circuit patterns are laminated, in which a circuit pattern having a signal line is formed on the inner layer, and pads and lands for mounting components, through-hole lands for connection, and a power source are formed on the outer layer. Or a multilayer printed circuit board characterized by forming a solid pattern for grounding. 2. The multilayer printed circuit board according to claim 1, further comprising a plating layer that electrically connects the power supply or ground solid patterns formed on both outer layers at the periphery thereof. 3. The multilayer printed circuit board according to claim 1, wherein the surface of the solid pattern for power supply or ground formed on the outer layer is coated with a radio wave absorber.