JPS6398194A - Manufacture of injection-molded unit with circuit - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing an injection molded body with a circuit, in which an FPC (flexible printed circuit) is fixed to the injection molded body.

[Prior art and its problems]

FPC is made by pasting copper foil on one or both sides of an insulating film and etching it to form a desired circuit pattern, and is used as a wiring material in electronic devices because it is thin and highly flexible.

On the other hand, injection molded resin bodies are generally used as housings for electronic devices.

In conventional electronic devices, the injection molded body and FPC are manufactured separately and then the FPC is incorporated into the injection molded body.
It is difficult to fix because it is flexible.

Further, reinforcing ribs are usually formed on the injection molded product in order to ensure necessary strength and suppress deformation, but it is often necessary to arrange the FPC so as to cross the reinforcing ribs. An example thereof is shown in FIG. Reference numeral 1 denotes a box-shaped injection molded body, which includes a base plate 2 serving as a bottom or a ceiling, a peripheral wall 3,
The reinforcing ribs 4 and the like are integrally formed. 5 is an FPC on which a required circuit pattern is formed.0 As shown in the figure, in the part where the FPC 5 passes through the reinforcing rib 4, the reinforcing rib 4
It is necessary to provide a notch in the However, if a notch is provided in the reinforcing lip 4, the strength will be weakened, and the size and shape of the notch will naturally be limited, making design difficult. In addition, if the size of the notch is not large enough, it is necessary to narrow the FPC0 width by that part, and the FP
The structure of C becomes complicated and manufacturing becomes troublesome.

[Means for solving problems and their effects]

The present invention provides a method for manufacturing an injection molded article with a circuit that solves the problems of the prior art as described above, and the method involves inserting an FPC into an injection molding mold by directing the back side of the FPC into a mold cavity. Set it on the inner surface of the mold, and perform resin injection molding by wrapping the resin around part of the surface side of the FPC.
The resin part that wraps around a part of the front side of the FPC is used to create an FP.
This is characterized in that C is fixed to the injection molded body.

In this way, the FPC can be fixed to the injection molded body at the same time as the injection molding. In addition, by wrapping the resin around the front side of the FPC, a reinforcing lip can also be formed on the front side of the FPC, so there is no need to form a notch in the reinforcing rib for passing through the FPC [Example] Below, Embodiments of the present invention will be described in detail with reference to the drawings.

In this embodiment, in order to manufacture an injection molded body with a circuit as shown in FIG. 1, molds 6A and 6 as shown in FIGS.
Use B. When two molds 6A and 6B are combined,
A mold cavity 7 is formed which forms the base portion and peripheral wall portion of the box-shaped injection molded body. Furthermore, grooves 8 forming reinforcing ribs are formed in one mold 6A, and gates 9 are provided in the other mold 6B.

The molds 6A and 6B are the same as the conventional molds, but in the present invention, before injection molding, the FPC 5 is temporarily fixed to the inner surface of one of the molds 6A with an easily removable adhesive or the like. The FPC 5 is placed with its back side facing into the mold cavity 7 so as to cross the reinforcing lip formation 48. If you perform resin injection molding in this state,
The resin passes through the groove 8 as indicated by the arrow in FIG. 3 and flows around to the surface side of the FPC 5, filling the entire space in the molds 6A and 6B. After cooling, the molds 6A and 6B are removed, and an injection molded article 10 with a circuit as shown in FIG. 1 is obtained.

This injection-molded body 10 with a circuit is formed such that an FPC 5 is arranged on a substrate portion 2 of an injection-molded body 1, and reinforcing ribs 4 are formed to cross over the FPC 5. In other words, the FPC 5 is inserted into the injection molded body 1 by the reinforcing ribs 4 at the portion that passes through the reinforcing ribs 4.
It is fixed at . Note that when it is necessary to bond the FPC 5 to the substrate portion 2, injection molding may be performed after applying an adhesive to the back surface of the FPC 5.

In the above embodiment, the FPC is fixed to the injection molded body using reinforcing ribs, but as shown in FIG.
1, it is also possible to fix the FPC 5. In this case, when installing the FPC on the mold, there are 11 protrusions on the surface.
All you have to do is carve a groove to form this.

In the above embodiments, the case where the injection molded body is box-shaped has been described, but the injection molded body may have a shape other than that.

〔Effect of the invention〕

As explained above, according to the present invention, since the FPC can be fixed to the injection molded body at the same time as the injection molding, the FP
Fixing C becomes easier. In addition, the structure of the injection molded product is FPC.
The design of the injection molded product becomes easy because it is not affected by the arrangement of On the other hand, the structure of the FPC is not affected by reinforcing ribs of the injection molded product, so the design and manufacture of the FPC becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an injection molded body with a circuit manufactured according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state in which an FPC is set in a mold in an embodiment of the present invention. Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 2;
The figure is a partially cutaway perspective view showing an injection molded body with a circuit manufactured according to another embodiment of the present invention, and FIG. 5 is a partially cutaway perspective view showing a state in which an FPC is arranged in a conventional injection molded body. . 1 - Injection molded body, 2 - Substrate part, 3 - Peripheral wall part, 4 - Reinforcement rib, 5 - FPC16A/6B - Mold, 7 - Mold cavity, 8 - Groove, 9 - Gate, 10 - Injection molded body with circuit , 11 ~ protrusion. Figure 1 Figure 2 Figure 3”■8

Claims (2)

[Claims] (1) Set an FPC (flexible printed circuit) on the inner surface of an injection mold with its back side facing into the mold cavity, and wrap the resin around a part of the front side of the FPC. A method for manufacturing an injection molded body with a circuit, which comprises performing injection molding and fixing the FPC to the injection molded body using a resin portion that wraps around a part of the surface side of the FPC. (2) The method according to claim 1, comprising:
The resin wrapped around a part of the surface side of C forms part of the reinforcing ribs of the injection molded product.