JPH09186412A - Printed board suitable for component mounting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the necessity of aligning by a perforated cover lay film by the improvement of the dimensional accuracy of land by forming only the land for mounting a component on one side surface, forming an inner passage at the opposite side surface, and connecting the land to a circuit via a through hole. SOLUTION: Conductor layers of copper foils are provided on both side surfaces of base film of polyimide. A land 4 is formed on one side surface by etching, and a circuit 3 is formed on the opposite side. Then, the land 4 is connected to the circuit 3 by continuity via a through hole 5. An insulating resin layer 8 is provided at the circuit 3 side. Accordingly, an integral printed board with the built-in circuit 3 is obtained directly corresponding to the rear surface of the land 4 forming board, thereby unnecessitating a perforated cover lay film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a printed circuit board, particularly an FPC, suitable for mounting components. More specifically, in the present invention, since the circuit portion is directly formed corresponding to the back surface of the land portion forming substrate, the dimensional accuracy of the land portion is improved,
In addition, the present invention relates to a printed circuit board suitable for component mounting, which does not require a cover lay film having holes to be formed and aligned.

[0002]

2. Description of the Related Art As shown in FIG. 2, a surface of an FPC is usually provided with a circuit 3 and a land portion 4 for mounting components in a mixed manner, and a cover is further provided thereon to prevent a short circuit of the circuit 2. When the lay film layer 6 is provided, it is necessary to prepare the cover lay film 6 in which the holes 7 are formed in the portions corresponding to the land portions 4, align the positions, and then bond the cover lay film 6 together. Therefore, there is a limit to the accuracy of the land portion of the printed circuit board, and the positioning of the holes 7 provided in the coverlay film 6 is a troublesome operation.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printed circuit board in which the dimensional accuracy of the land portion is improved and it is not necessary to form a cover lay film having a hole for alignment. It is a thing.

[0004]

DISCLOSURE OF THE INVENTION As a result of various studies on the above-mentioned problems, the inventors of the present invention have provided a land portion for mounting components and a circuit portion on different surfaces, and have the land portion and the circuit portion electrically connected by through holes. The inventors have found that the connection can improve the dimensional accuracy of the land portion, and can provide a printed circuit board which does not require a cover lay film having a hole to be aligned for alignment, thereby completing the present invention.

That is, the present invention provides: a printed circuit board in which only one side has a land portion for mounting components, the circuit portion is formed on the opposite surface, and the land portion and the circuit portion are connected by through holes. Another feature is that an insulating plastic resin layer is provided on the side where the circuit is formed to facilitate component mounting.

A detailed description will be given below with reference to the drawings. FIG. 1 is a schematic view showing a manufacturing procedure of a printed circuit board of the present invention and its structure. In FIG. 1, (a) is a double-sided conductor board for FPC in which a conductor layer 2 such as a copper foil is provided on both sides of a board film 1. Next, the double-sided plate is appropriately etched (b). Is a front surface A on which only the land portion 4 is formed, (c) is a back surface B on which only the circuit 3 is provided at a predetermined position corresponding to the land portion 4, and (d) is a land on the front surface A. The portion 4 and the circuit 3 on the back surface B are electrically connected by the through hole 5.
It is a printed circuit board that is a connected finished product.

Further, 1 is a base film, 2 is a conductor layer such as copper foil, 3 is a circuit, 4 is a land portion for mounting electric / electronic parts, 5 is a through hole, 6 is a coverlay film, and 7 is Hole for exposing land 4 and 8 for backside B
It is an insulating resin layer provided on the side. A procedure for manufacturing the printed circuit board of the present invention will be described.

First, using the double-sided copper foil substrate shown in (a), the conductor part other than the land part is removed by an operation such as etching as shown in (b) to mount the electric / electronic parts. The front surface A provided with the land portions 4 is formed, and only the circuit 3 is provided on the back surface B as shown in FIG. 3C, then the through hole 5 is provided, and the conduction path is formed on the inner surface by plating or the like. , The land portion and the circuit 3 are electrically connected and connected to each other to produce the finished product shown in FIG.

[0009]

As described above, the coverlay film can be easily provided on the surface of the printed circuit board of the present invention on which only the circuit is provided, and on the side where only the land portion is provided, Since the components are mounted as they are, a coverlay film is unnecessary. That is, in order to prevent a short circuit in the circuit part, it is not necessary to process the hole 7 in the coverlay film,
Moreover, the process of bonding the coverlay film by aligning the hole 7 and the land portion 4 is unnecessary. Further, by providing a hard insulating plastic resin layer of various nylon, acrylic resin, PTB resin or the like on the side on which the circuit is provided, the action of the reinforcing plate works and the component mounting on the land portion can be facilitated. .

[0010]

The present invention is illustrated by the following examples, which do not limit the scope of the invention. 1 in Figure 1 (a)
The conductor layer 2 made of copper foil having a thickness of 35 μm was provided on both surfaces of the polyimide base film having a thickness of 50 μm shown in FIG. The land portion 4 shown in (b) is formed on one surface by etching, and the circuit portion 3 shown in (c) is formed on the opposite surface, and then the land portion 4 and the circuit portion 3 are electrically connected by the through hole 5.
I was connected. Then, the insulating plastic resin layer 8 was provided on the circuit portion side. Therefore, it can be seen that an integrated printed board in which a circuit portion is directly formed corresponding to the back surface of the land portion forming substrate is obtained, and a cover lay film having a hole is unnecessary. In addition, FIG. 3 shows that the double-sided structure FPC (a) formed by the method shown in FIG. 1 is attached to an insulating plastic resin layer 8 as a protective plate which is preformed in a predetermined shape to mount it on an electronic component. It is a schematic diagram explaining the completed molded product image shown in (c).

[0011]

The land portion for mounting the component and the circuit portion are provided on different surfaces, and the through-holes are electrically connected and connected to each other, thereby improving the dimensional accuracy of the land portion and further facilitating the continuous formation of the land portion. In addition, it is possible to provide a printed circuit board that can be easily attached to a circuit protection film or a molded product, and can be easily mounted with components.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a manufacturing procedure of a printed circuit board of the present invention and its structure.

FIG. 2 is a schematic diagram showing a structure of a conventional printed circuit board.

FIG. 3 is a double-sided structure FP formed by the method shown in FIG.
C (a) and insulating plastic resin layer as protective plate
FIG. 8 is a schematic diagram illustrating an image of a completed molded product (C) suitable for mounting electronic components by bonding (B) and (B).

[Explanation of symbols]

 1 base film 2 conductor layer 3 circuit part 4 land part 5 through hole 6 coverlay film 7 hole 8 insulating plastic resin layer

Claims (2)

[Claims] 1. A printed circuit board, wherein one side is formed with only a land portion for mounting components, the circuit portion is formed on the opposite surface, and the land portion and the circuit portion are connected by a through hole. 2. The printed circuit board according to claim 1, wherein an insulating plastic resin layer is provided on the side on which the circuit is formed to facilitate mounting of components.