JPH03163897A - Circuit board device - Google Patents

Abstract

PURPOSE:To remove noise from a power source circuit without using any noise removing capacitor to be inserted between the power source circuit and an earthed circuit by using a ferroelectric substance for the first insulating layer. CONSTITUTION:This circuit board device is constituted of the first conductive layer 1, first insulating layer 2, second conductive layer 3, second insulating layer 4, third conductive layer 5, fourth conductive layer 6, third insulating layer 7, via holes 8, through holes 9, and insulating spaces 10. A ferroelectric substance is used for forming the first insulating layer 2 formed between the first conductive layer 1 forming an earthing circuit and the second conductive layer 3 forming a power supplying circuit. As a result, such a state that a capacitor is inserted between the circuits 3 and 1 from the view point of the distributed constant is set up and a fault to a signal circuit can be prevented by removing the noise superimposed upon the power supplying circuit 3 over the entire front surface of this circuit board device. Therefore, the noise of the power supplying circuit can be removed without using any capacitor to be inserted between the power supplying circuit and earthing circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit board device for digital circuits such as computers.

[Prior Art] As shown in FIG. 2, a conventional circuit board device of this type includes a first conductive layer 11 forming a first signal circuit made of copper foil;
One surface of the second conductive layer l3 forming a grounding circuit made of copper foil and the first surface made of a glass-based epoxy resin laminate or the like.
One side of the third conductive layer 15 which forms a power supply circuit made of copper foil and a second side made of copper foil which is adjacent to each other with an insulating layer 12 in between.
A fourth conductive layer 17 forming a signal circuit is adjacent to the second insulating layer 14 made of a glass-based epoxy resin laminate or the like, and is adjacent to the other surface of the second conductive layer l3. Said third
The other surface of the conductive layer 15 is heated and bonded to the other surface of the conductive layer 15 through a third insulating layer 16 made of glass cloth impregnated with a semi-hardened epoxy resin called prepreg. By the way, there is a problem in that the power supply circuit 15 is often contaminated with noise during operation, and is superimposed, causing damage to electrical components such as integrated circuits installed in the signal circuits 11 and 17. A capacitor 18 interposed between the power supply circuit l5 and the ground circuit l3 to remove noise.
was inserted near the integrated circuit. However, this method only provides a local effect and therefore requires a large number of capacitors to obtain a sufficient effect.
In addition to increasing the cost of the capacitor, there are also problems in that the circuit board device also becomes larger. In addition, 20 is a through hole for inserting the terminal 19 of the capacitor 18, and 21 is the first signal circuit 11 and the ground circuit 13.
22 is a via hole for electrically connecting the first signal circuit 11 and the power supply circuit 15; 23 is the through hole 20 and the via holes 21 and 22; This is an insulating space that electrically isolates the surrounding electrical circuit.

[Problem to be solved by the invention]

The present invention solves the above conventional drawbacks and provides a circuit board device that can eliminate noise in a power supply circuit without requiring a noise elimination capacitor inserted between the power supply circuit and the ground circuit. The purpose is

[Means to solve the problem]

In order to solve the above problems, in the present invention, a second conductive layer is formed on one side of the first conductive layer via the first insulating layer, and a second conductive layer is formed on the other side of the first conductive layer. 3. A circuit board formed by forming a third conductive layer through an insulating layer of 2, wherein the first insulating layer is a ferroelectric layer, the first conductive layer is a ground circuit, and the second conductive layer is a ground circuit. was used as the power supply circuit.

[Operation] According to the above structure, the first insulating layer interposed between the first conductive layer forming the ground circuit and the second conductive layer forming the power supply circuit is made of a ferroelectric material. A capacitor is inserted between the power supply circuit and the ground circuit in a distributed constant manner, and noise superimposed on the power supply circuit across the front surface of the circuit board device is removed to prevent damage to the signal circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of the main part of the circuit board device of the present invention, 1
is a first conductive layer, and a ground circuit is formed of copper foil or the like. 2 is a first insulating layer provided on one end side of the first conductive layer l, which is mainly made of a ferroelectric material such as barium titanate;
This is mixed with a thermosetting adhesive. 3 is a second conductive layer provided on one end side of the first conductive layer 1 via the first insulating layer 2-4, and a power supply circuit is formed of copper foil or the like. 4
is a second insulating layer formed on the other end side of the first conductive layer 1, and is made of a glass-based epoxy resin laminate or the like.

Reference numeral 5 denotes a third conductive layer provided on the other end side of the first conductive layer 1 via the second insulating layer 4, on which a first signal circuit and the like are formed of copper foil or the like. Reference numeral 6 denotes a fourth conductive layer adjacent to the second conductive layer 3 via a third insulating layer 7, on which a second signal circuit and the like are formed of copper foil or the like. Note that the third insulating layer 7 is made of the same material as the second insulating layer 4 described above. 8 is the first conductive layer l and the third conductive layer l.
a plurality of via holes for electrically connecting conductive layers such as the conductive layer 5, 9 a plurality of through holes for inserting terminals of electrical components, 10 a through hole 9 and the This is an insulating space that electrically insulates the pie hole 8 from the surrounding electric circuit. Next, an example of the manufacturing process for the above-described structure will be explained. First, copper foil is bonded to both sides of the second insulating layer 4 in advance, and this copper foil is etched to form the above-mentioned ground circuit. 1 and a first signal circuit 5 are respectively formed. Further, the power supply circuit 3 and the second signal circuit 6 are similarly formed on both surfaces of the third insulating layer 70. Thereafter, the first insulating layer 2 described above is formed on the surface of the grounding circuit 1 or the power supply circuit 3 by painting or the like, and after drying, the grounding circuit 1 and the power supply circuit 3 are formed through the first insulating layer 2. are bonded together, and the first insulating layer 1 is cured by heating while applying pressure to the whole. Thereafter, holes for the pire holes 8 and through holes 9 are provided at predetermined positions, and chemical plating or the like is applied to these holes to complete the manufacturing process. And according to this example,
For example, in a 20 cm square circuit board device, the first insulating layer 2 is made of a dielectric material with a dielectric constant of 10,000 and has a thickness of 0.3 cm.
mm, the first conductive layer 1 and the second conductive layer 3
A capacitance of about 12 μF can be obtained between the two.

〔Effect of the invention〕

As described above, according to the present invention, the first
Since the first insulating layer between the conductive layer and the second conductive layer forming the power supply circuit is formed of a ferroelectric material, a capacitor is disposed between the power supply circuit and the ground circuit in a distributed manner. When inserted, the noise superimposed on the power supply circuit across the front of the circuit board device can be removed to prevent damage to the signal circuit, eliminating the need for multiple capacitors to remove this noise. It is possible to downsize the circuit board device and improve the reliability of the device.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted side sectional view for explaining the outline of the circuit board device of the present invention, and FIG. 2 is a partially omitted side sectional view of a conventional example. ■...First conductive layer, 2...First insulating layer, 3...
・Second conductive layer, 4... second insulating layer, 5... third
conductive layer.

Claims (2)

[Claims] (1) A second conductive layer is formed on one side of the first conductive layer with a first insulating layer interposed therebetween, and a second conductive layer is formed on the other side of the first conductive layer with a second insulating layer interposed therebetween. 1. A circuit board device comprising a third conductive layer, the first insulating layer being a ferroelectric material. (2) The circuit board device according to claim (1), wherein the first conductive layer comprises a ground circuit, and the second conductive layer comprises a power supply circuit.