JPH0737327Y2 - Printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a printed wiring board.

<Prior art> Conventionally, the flexible printed wiring board (FPC) material of the composite multilayer printed wiring board is a flexible film made by applying an adhesive to a polyimide film called a film cover lay on the FPC material by thermocompression bonding. Part of the conductor is protected. The film coverlay also provides insulation between the conductors on the rigid printed wiring board (PWB) material and the PFC material.

FIG. 5 is a perspective view of a conventional composite multilayer printed wiring board, FIG.
The figure is a sectional view thereof.

As shown in FIG. 5, the composite multilayer printed wiring board is composed of a rigid portion 80A and a flexible portion 80B.

Further, as shown in FIG. 6, the film cover lay 20 is thermocompression bonded onto the conductor pattern 60 pattern-etched in the copper-clad FPC material 10. More flexible part 80
The adhesive sheet 30 and the copper-clad PWB material 40 are laminated on the part excluding B. Through hole 70
Are formed, and the through holes 70 are plated. A solder resist 50 is applied on the conductor pattern 60 on the surface of the substrate.

In the composite multilayer printed wiring board having the above-described structure, generally, the electronic part is mounted on the rigid portion 80A, and the flexible portion 80B formed of the FPC material 10 serves as a cable for connecting the wiring of each rigid portion 80A. Since this flexible portion 80B is desired to be easily bent, even when using a double-sided copper-clad FPC material, the conductor is formed on only one side, the opposite side does not leave the conductor, and the film cover lay is also used. Do not stick.

<Problems to be Solved by the Invention> By the way, when the flexible portion 80B of the conventional composite multilayer printed wiring board is bent, the state is as shown in FIGS.
As shown in the figure.

FIG. 7 is a state diagram when the flexible portion 80B is bent while the rigid portion 80A is held. Therefore, in order to fix the rigid portion 80A in the shape as shown in FIG. 8, the portion to be bent is pushed and bent by applying force in the direction of the arrow with a finger. In this case, a strong force is partially applied to the conductor,
When the conductor is cracked and such bending is repeated, the wire is often broken. Further, even if the conductor is cracked, it cannot be found in appearance, and there is a problem in that a wiring board having a reduced reliability is used. In addition, when bent at the boundary between the rigid portion 80A and the flexible portion 80B as shown in FIG. 9, damage 90 may occur at the end of the flexible portion 80B as shown in FIG.

In the present invention, without causing damage to the FPC material 10 as described above, without giving an excessive force to a portion to be bent,
An object of the present invention is to provide a composite multilayer printed wiring board that can be easily bent.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the printed wiring board of the present invention is a double-sided copper-clad flexible printed wiring board having conductor patterns formed on both sides, and the conductor pattern is covered. A film cover lay and a plurality of hard printed wiring boards that sandwich the flexible printed wiring board and are laminated so that a part of the flexible printed wiring board is exposed as a flexible portion, and one surface of the flexible printed wiring board is provided. In a printed wiring board in which the conductor pattern formed on the flexible printed wiring board and the hard printed wiring board are led out from a laminated portion to a flexible portion, the other surface of the flexible printed wiring board has a surface thereof. The film cover lay that covers is more flexible than the above laminated part It is characterized in that a film cover lay for adjusting the bending is provided on a portion of the flexible portion that does not need to be bent.

<Operation> By forming the film cover lay on the flexible portion at a position where it does not need to be bent, the range in which the thickness is increased by the film cover lay becomes less likely to bend than the other ranges. Therefore, when the rigid portion is bent while being bent, only the range to be bent can be bent.

The film cover lay covering the other surface of the flexible printed wiring board is unnecessary in the bent portion, and is removed.

<Embodiment> FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a bottom view showing details thereof. Embodiments of the present invention will be described in detail below with reference to these drawings.

As shown in FIG. 2, the composite multilayer printed wiring board according to the embodiment of the present invention comprises a rigid portion 8A and a flexible portion 8B.

As shown in FIG. 1, a film cover lay 2 is formed on the conductor pattern 6 that is pattern-etched on the copper-clad FPC material 1.
Are thermocompression bonded. Further, the adhesive sheet 3 and the copper-clad PWB material 4 are laminated on the portion excluding the flexible portion 8B. Through holes 7 are formed in the substrate in such a state, and the through holes 7 are plated.
A solder resist 5 is applied on the conductor pattern 6 on the surface of the substrate. Through the above steps, the conductor pattern 6 is formed on one surface of the flexible portion 8B, and the conductor pattern 6 is covered with the film cover lay 2. Further, the film cover lay 2 is attached to the other surface in a region where it is not necessary to bend it.

FIG. 3 is a sectional view of another embodiment of the present invention, and FIG. 4 is a bottom view showing details thereof.

The structure shown in FIG. 3 is similar to the structure shown in FIG. 1 except that the conductor pattern 6 is formed on the opposite side of the wiring pattern of the flexible portion 8B in a region that does not need to be bent, and the film cover layer is further formed on the conductor pattern 6. 2 is formed. In this case, the shape of the conductor pattern 6 is freely formed, for example, the entire surface or a mesh shape. on the other hand,
The film cover lay 2 need only cover the conductor pattern 6 and may cover the entire flexible portion 8B.

<Effect of the Invention> As described above, according to the printed wiring board of the present invention, the film cover lay covering the surface of the other side of the flexible printed wiring board extends from the laminated portion to the flexible portion. Since the flexible portion is not required to be bent, a film cover lay for adjusting the bending is provided, so when bending the flexible portion, it is easy to hold the rigid portion. It can be bent, and the applied force is small, so that no excessive force is applied to the bent portion. As a result, the desired bending radius can be set without damaging the FPC material. Therefore, a highly reliable printed wiring board can be formed. Further, in the manufacture of the printed wiring board of the present invention, after the conventional manufacturing process of covering the other surface of the flexible printed wiring board with the film cover lay which is a single sheet, the film cover lay corresponding to the bent portion is formed. The conventional manufacturing method can be applied as it is by considering such a removed portion of the film cover lay. Therefore, it is not necessary to add a manufacturing process and a separate material is prepared. Since it is not necessary, there is no increase in material cost.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a bottom view showing the details thereof omitted, FIG. 3 is a sectional view of another embodiment of the present invention, and FIG. 5 is a perspective view of a conventional example, FIG. 6 is a sectional view thereof, and FIGS.
The figure shows a state in which the flexible portion is bent. 1 ... Copper-clad FPC material 2 ... Film cover lay 3 ... Adhesive sheet 4 ... Copper-clad PWB material 6 ... Conductor pattern 7 ... Through hole

Claims (1)

[Scope of utility model registration request] 1. A double-sided copper-clad flexible printed wiring board having conductor patterns formed on both sides, a film cover lay covering the conductor pattern, and a flexible printed wiring board sandwiching the flexible printed wiring board. A plurality of hard printed wiring boards that are laminated so that the portions are exposed as flexible portions, and the flexible printed wiring board and the hard printed wiring board are laminated with a conductor pattern formed on one surface of the flexible printed wiring board. In the printed wiring board derived from the laminated portion to the flexible portion, on the other surface of the flexible printed wiring board, a film cover lay covering the surface is formed to extend from the laminated portion to the flexible portion, For the part of the above flexible part that does not need to be bent Printed circuit board, characterized in that the film coverlay for performing bending adjustment is provided.