JPH0422357B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a molded product having printed wiring along its surface, and can be used for cases and parts of industrial, office, and home electronic devices.

(Prior art) Conventionally, in the fields of industrial, office, and household electronic equipment, wiring has been carried out on the surface of electrically insulating substrates made of glass cloth-based epoxy resin, paper-based epoxy resin, paper-based phenolic resin, etc. A circuit similar to the above is constructed using a printed circuit board with a conductive pattern based on the electrical design formed and fixed using conductive material such as silver ink and coated with insulating varnish to protect the circuit, or polyester film, polyimide film, etc. The formed flexible printed wiring sheet was attached to the inside of the casing by screwing the ends. At this time, the printed wiring board and flexible printed wiring sheet are located in the space inside the housing, and the flexible printed wiring sheet in particular is flexible, so it is set in a bent or bent state within the housing space. There were many things.

(Problems to be solved by the invention) Conventional printed wiring boards are hard flat boards;
Therefore, the conductive pattern provided on this board is also limited to a planar design. In addition, the printed wiring board is attached to the casing etc. in which it will be used with screws, etc.
This severely limits the shape of the product, requiring unnecessary space, and the weight of the printed wiring board increases the overall weight of the product. .

Since the base material of the flexible printed wiring sheet is lightweight and flexible, the above-mentioned weight problem has been alleviated, and restrictions on product shape have been alleviated to some extent.
However, a flexible printed wiring sheet attached to a casing or the like is set with its ends fixed and the middle part floating within the space of the casing.
For example, when installed on the lower side of a housing that is divided into upper and lower parts, the upper side of the housing is often moved vertically and horizontally in order to attach or remove the upper side of the housing. There are new cases where parts installed on the upper side of the case get caught on the flexible printed wiring sheet, damaging the wiring, or where the flexible printed wiring sheet is sandwiched between parts and bent. This caused a problem.

Furthermore, even when using a flexible printed wiring sheet, when designing the casing, it is necessary to prepare a space for screwing the flexible printed wiring sheet and a space for storing the flexible printed wiring sheet in advance. It required an unnecessary amount of space similar to when in use.

Today, the demand for smaller and lighter products has become even greater, and conventional printed wiring boards and flexible printed wiring sheets are no longer able to meet these demands.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the three-dimensional molded product having printed wiring according to the present invention has the following structure, that is, it is made of flexible plastic made of polyester, polyimide, etc. A conductive layer formed as an electric circuit by a method such as printing, vapor deposition, or transfer is provided on at least one side of the base film. The electric circuit is usually made of metal such as silver ink, and in order to prevent oxidation and to prevent shoots due to adhesion of foreign substances, at least the part of the conductive layer excluding the contacts for connecting other electric parts, etc. Covered with an insulating material such as insulating varnish or plastic film. Further, it is desirable that the contacts are also coated with a conductive material, such as carbon ink, for the purpose of preventing oxidation.

In addition, one side of the sheet (the side without an electric circuit or a part without an electric circuit) is coated with polyurethane, ethylene-vinyl acetate copolymer ( EVA), chlorinated polypropylene (chlorinated PP) to form a heat-sealing resin layer.

An injection resin layer is formed into a three-dimensional shape, for example, a housing shape, by injection molding on the heat-sealable resin layer side of the wiring sheet thus obtained, thereby completing the present invention.

(Function) In the structure of the three-dimensional molded product having printed wiring according to the present invention, an electrical circuit necessary for the product is housed in the conductive layer provided on the base film.
A coating of insulating varnish or plastic film on the conductive layer prevents deterioration of the conductive layer's electrical circuits due to oxidation, damage caused by contact with other parts, and prevents shoots due to adhesion of foreign matter. Contacts are necessary to connect electrical parts, and if a layer of conductive material, such as carbon ink, is provided on the contacts, it can prevent deterioration of the contact parts due to oxidation and impair their function as contacts. There's nothing wrong with that.

The heat-sealing resin layer consists of a wiring sheet with an electric circuit formed thereon and an injection resin layer (i.e., a plastic molded product).
and firmly adhere to each other.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view partially showing an embodiment of the present invention, and is shown in a simplified plan view for the sake of explanation.

A base film 5 made of 50μ polyester,
Surface resistance: 0.05Ω/mm Electric circuit 3 is silk screen printed using silver ink, 4 lines/mm in most areas.
Provided at the pitch of At that time, the thickness of the electric circuit layer is adjusted to 5 to 10 microns. Apply a coating layer of 10 to 10cm to the part that will become contact 1 by silk screen printing using carbon ink with a surface resistance of 50Ω/mouth.
Provided with a thickness of 15μ. Furthermore, an insulating varnish layer 4 with a thickness of 10 to 15 microns is provided so as to cover the parts other than the parts that will become the contacts of the electric circuit. Further, on the surface of the polyester base film opposite to the surface having the electric circuit layer, a heat-sealing resin layer 6 made of ethylene-vinyl acetate copolymer (EVA) was applied after drying at a rate of 5 g/min.
Apply to make ² m2. After punching out the wiring sheet made in the above manner to a predetermined size, place the wiring sheet at the desired position in the injection mold for the telephone distribution machine housing so that the electrical circuit layer side of the wiring sheet is in contact with the mold. After that, molten ABS resin is injected and molded. When setting the sheet, the sheet comes into contact with the sheet conveyance means, the mold, etc., but since the printed wiring part is covered with an insulating layer, there is no chance that the wiring will be damaged and disconnected, or that it will get dirty and be shot. There's nothing to do. And the heat fusion resin is
Three-dimensional molding that is melted by the heat of the molten ABS resin, solidified as the molded product cools, and is integrated with the injection resin layer (plastic molded product) 7 in close contact with it, and has printed wiring along the surface according to the present invention. product was formed.

(Effects of the Invention) In the three-dimensional molded product having printed wiring according to the present invention, the wiring sheet on which the electrical circuit is formed and the injection resin layer (plastic molded product; for example, the casing) are in close contact with each other, and it appears that the electrical circuit is in the casing. It is provided along the three-dimensional shape of the surface or inner surface of the body. This eliminates the unnecessary space that occurs when conventional printed wiring boards and flexible printed wiring sheets are used, and also makes it possible to freely design the shape of products, which was previously subject to major restrictions. Summer. Additionally, there is no need to worry about damage to the electrical circuits caused by protrusions on the casing or the sheet getting caught on other parts, which was a problem when using flexible printed wiring sheets. Furthermore, since the sheet is brought into close contact with the molded product at the same time as the molding, the printed wiring portion is covered with an insulating layer even when the sheet is set in the mold, so there is no risk of disconnection or shorting. Regarding the problem of weight, since a lightweight film is used as the base material, the weight does not increase.

In this way, the three-dimensional molded product having printed wiring according to the present invention solves the conventional problems and satisfies the demand for smaller and lighter products.

[Brief explanation of drawings]

The drawing is an explanatory diagram showing a partial cross section of an embodiment according to the present invention. 1: Contact, 2: Carbon ink layer, 3: Electric circuit (conductive layer), 4: Insulating varnish layer, 5: Base film, 6: Heat fusion resin layer, 7: Injection resin layer (plastic molded product).

Claims (1)

[Claims] 1 A conductive layer formed as an electric circuit by a method such as printing is provided on at least one side of a flexible plastic base film, and at least contacts for connecting other electric parts, etc. of the conductive layer are excluded. A prefabricated wiring sheet in which an electric circuit is formed by providing an insulating layer on the portion and a heat-sealing resin layer on one side of a base film, and a heat-sealing resin of the wiring sheet. A three-dimensional molded product with printed wiring on the surface, consisting of a three-dimensional injection resin layer formed by injection molding on the layer side.