JPH07170080A - Printed board and electrical component package - Google Patents

Abstract

PURPOSE:To provide a printed board and an electrical component package which are both high enough in shielding effect. CONSTITUTION:At least two insulating layers b and three conductor layers a and L are alternately laminated for forming a printed board 1, at least the conductor layer L is set different in area from the insulating layer b, or the conductor layers a and L are set different in area from each other. By this setup, a conductor layer can be not only utilized as a shielding conductor but also enhanced in shielding effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board and an electric component mounting body used in various electronic devices such as a liquid crystal display device, an image reading device, an image forming device and a computer.

[0002]

2. Description of the Related Art A conventional printed circuit board is shown in FIG. Figure 1
1 is a multilayer printed circuit board, 2 is a resistance element as a functional element mounted on the board, 3 is a wiring pattern, 4 is a connection pad (land), 5 is a through hole, and a is a conductor layer for forming an electric circuit. Used for construction purposes. b is an insulating layer for the purpose of insulating between different conductor layers a. Insulating layer b
Conduction between the conductor layers a separated by is generally configured using a through hole.

There are the following two methods for reducing the radiation noise from the printed circuit board and the influence of external noise on the printed circuit board.

1. As in the shield system shown in FIG. 2, in order to shield the printed circuit board 1 together with the shield plate 8 in the housing, a part of the surface conductor layer of the printed circuit board 1 is provided with a connecting portion 9 of the shield plate 8. The GND part 6 corresponding to is provided.

2. As in the shield method shown in FIG. 3, the front and back surface conductor layers f of the printed circuit board 1 are connected to the GND plane f.
Configure as.

Here, 11 is an opening.

[0007]

However, in these techniques, the former 1. Then, the GND portion 6 of the surface layer and the GND plane of the interior have a sufficient number of through holes 7
The electrical connection is made by the above, and the contact area between the GND portion 6 of the surface layer and the shield plate 8 is small.

The latter 2. Then, it is necessary to provide a large number of holes 11 in the GND plane f of the surface conductor layer because of through holes and lands for arranging components on the printed circuit board. As described above, the conventional technique may not be able to obtain a satisfactory shield effect.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed circuit board and an electrical component mounting body which can have a sufficient shielding effect.

Another object of the present invention is to make at least one area of the conductor layer different from the area of the insulating layer in a printed circuit board in which at least two insulating layers and at least three conductor layers are alternately laminated. Another object of the present invention is to provide a printed circuit board and an electrical component mounting body in which at least two areas of the conductor are different from each other.

Another object of the present invention is to have a printed circuit board in which at least two insulating layers and at least three conductor layers are alternately laminated, and at least one of the conductor layers is extended more than a laminated portion and has a predetermined size. Another object of the present invention is to provide an electrical component mounting body including a printed circuit board, which is characterized in that it is connected to a reference voltage source for holding it at the potential.

Still another object of the present invention is at least 2.
A printed circuit board in which one insulating layer and at least three conductor layers are alternately laminated, and at least one of the conductor layers is provided.
One having a shape that does not reach the end of the laminated portion, and the remaining conductor layer at the end is connected to a reference voltage source for holding at a predetermined potential. It is to provide a component mounting body.

According to the present invention, not only the conductor layer can be easily used as a conductor for shielding, but also the shielding effect can be improved.

[0014]

(Embodiment 1) FIG. 4 is a perspective view of an electric component mounting body as an embodiment of a printed circuit board 1 to which the present invention is applied, and FIG. 5 is a sectional view of the printed circuit board 1. In FIGS. 4 and 5, a and L are conductor layers, the conductor layer L is a GND plane, and is a layer connected to a reference voltage source RPS that provides a reference potential such as a connection potential. The conductor layer a is formed for the purpose of forming an electric circuit pattern, and the electric parts 2, 2b, 2
c and 2d are mounted. b is each conductor layer a,
It is an insulating layer for the purpose of insulating L. In particular, the conductor layer L is formed by laminating materials having an area larger than that of the other conductor layer a, and is a feature of the present invention. Of course, in the conductor layer L, the conductor is removed at the position corresponding to the hole 11 (see FIG. 4B). Therefore,
The area referred to in the present invention is an area defined by the outer circumference of each layer.

When the printed circuit board shown in FIG. 4 is processed, the conductor layer L is formed into a box shape like the shield method shown in FIG. 6, and the laminated portion SP is housed inside, a printed circuit board having a sufficient shield effect is obtained. can get. Furthermore, it goes without saying that a more sufficient shield effect can be obtained by bonding the joint portion of the conductor layer L with something like solder.

4, 5 and 6, only the digital circuit is formed on the conductor layer a on one side of the conductor layer L, and only the analog circuit is formed on the conductor layer a on the other side. In FIG. 6, reference numeral 12 is a one-point grounding conductor for making the ground potential of the digital circuit and the analog circuit common. Further, 12 may use a through hole in the printed board.

Further, the means for attaching the printed circuit board shown in FIGS. 4, 5 and 6 to a housing or the like is an insulating layer b between the conductor layers 1.
Is formed in advance as shown in FIG. 7,
If the conductor layer L is attached only at the portion of the flat surface 13 in FIG. 7, the attachment portion 14 can be used for attachment.

(Embodiment 2) FIG. 8 shows a second embodiment of a printed circuit board to which the present invention is applied. The printed circuit board shown in the figure is the same as that shown in FIGS. 4 and 5 except that the conductor layer L is one. When this is electrically covered with a shield box 15 formed of a conductor from above and below like the shield method shown in FIG. 9, a printed circuit board having a sufficient shield effect similar to that in FIG. 6 can be obtained. Further, the shield box 15 and the conductor layer L may be bonded by using something like solder.

(Embodiment 3) FIG. 10 shows a sectional view of a third embodiment of a printed circuit board to which the present invention is applied. In the figure, a and n are conductor layers, the conductor layer a is a GND plane,
The conductor layer n is formed for the purpose of forming an electric circuit.
b is an insulating layer for the purpose of insulating the respective conductor layers a and g. In particular, the conductor layer j is formed by laminating materials having an area smaller than that of the other conductor layer a, which is another feature of the present invention.

By electrically connecting the U-shaped conductor 16 to the printed circuit board shown in the same figure as in the shield method shown in FIG. 11, a shield in the horizontal direction as well as in the vertical direction of the board can be obtained. At this time, since the inner conductor layer n does not reach the end face, it is not necessary to maintain the clearance between the printed board and the conductor 16.

(Fourth Embodiment) Further, a fourth embodiment is shown in FIG.
Shown in. In this case, instead of the conductor 16 in FIG. 11, a large number of through holes are provided at the edge of the substrate and the upper and lower conductor layers a are in contact with each other, so that the same effect as the third embodiment can be obtained.

(Embodiment 5) FIG. 13 shows an electric component mounting body using a printed circuit board according to Embodiment 5 of the present invention. In this example, six insulating layers b are laminated and bonded via conductive layers (patterned into a desired wiring shape) a and L therebetween. The conductive layer L is provided so as to extend outward from two sides sandwiching at least one corner, and the shield cover 15 made of a conductor is connected to this portion,
It is provided so as to cover the IC 2d as the functional element. Reference numeral 3 is a printed wiring on the front surface side, which is also connected to the shield cover 15. And the shield cover 15a
The IC 2d is electrically shielded by being connected to a reference voltage source (not shown) through the conductive layer L and holding it at a predetermined potential.

[0023]

As described in detail above, at least one conductor layer of the printed circuit board can be easily used as a shield means, and an electric component mounting body which is easy to mount on a device and has a high shielding effect can be obtained. .

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a conventional printed circuit board.

FIG. 2 is a schematic diagram showing a conventional shield method for a printed circuit board.

FIG. 3 is a schematic view showing another shield system of a conventional printed circuit board.

FIG. 4 is a schematic perspective view showing an electrical component mounting body using a printed board according to a first embodiment of the present invention.

FIG. 5 is a cross-sectional view of the printed circuit board according to the first embodiment.

FIG. 6 is a schematic diagram showing a shield method using the printed circuit board of Example 1.

FIG. 7 is a perspective view showing an example of a conductor layer used in the present invention.

FIG. 8 is a perspective view of a printed circuit board according to a second embodiment of the present invention.

FIG. 9 is a schematic diagram showing a shield system for a printed circuit board according to a second embodiment.

FIG. 10 is a sectional view of a printed circuit board according to a third embodiment of the present invention.

FIG. 11 is a schematic diagram showing a shield system for a printed circuit board according to a third embodiment.

FIG. 12 is a schematic diagram showing a shield system for a printed circuit board according to a fourth embodiment of the present invention.

FIG. 13 is a schematic diagram showing a shield system for a printed circuit board according to a fifth embodiment of the present invention.

[Explanation of symbols]

 a, L conductor layer b insulating layer

Claims (6)

[Claims] 1. At least two insulating layers and at least three
In a printed circuit board where two conductor layers are alternately laminated,
A printed circuit board, wherein at least one area of the conductor layer is different from the area of the insulating layer. 2. At least two insulating layers and at least three
In a printed circuit board where two conductor layers are alternately laminated,
A printed circuit board, wherein at least two areas of the conductor layer are different from each other. 3. An electrical component mounting body comprising the printed circuit board according to claim 1, wherein the conductor layer is held at a predetermined potential. 4. At least two insulating layers and at least three
A printed circuit board in which two conductor layers are alternately laminated, at least one of the conductor layers is extended from a laminated portion, and is connected to a reference voltage source for maintaining a predetermined potential. An electric component mounting body including a printed circuit board. 5. At least two insulating layers and at least three
A printed circuit board in which two conductor layers are alternately laminated, and at least one of the conductor layers is shaped so as not to reach the end of the laminated portion, and the remaining conductor layers are held at a predetermined potential at the end. An electrical component mounting body comprising a printed circuit board, which is connected to a reference voltage source for operating. 6. An electric device having a printed circuit board according to claim 1, further comprising a conductor cover connected to an extended portion of the conductor layer for electrically shielding the functional element by the cover. Component mount.