JPH06291441A - Manufacture of printed circuit substrate - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing printed circuit substrates of three dimensional composition. CONSTITUTION:In order to manufacture printed circuit substrates connected by a flexible sheet provided with the wiring part wherein circuit substrate parts are connected to respective circuit parts of the circuit substrate parts, a carrier sheet 50 wherein a circuit pattern 55 comprising a circuit part and a wiring part is formed to form a notch in the sheet is arranged so as to locate the circuit pattern 55 of the circuit part inside a cavity 33 corresponding to the circuit substrate part. Next, the inside of the cavity 33 is filled up with a melted down resin to form the circuit substrate part integrated with the circuit pattern 55 as well as the carrier sheet 50 in the circuit substrate edge part in the part encircled by the notch is heated by thermal welding heaters 45 in a metallic mold so as to be welded into the circuit substrate edge part later to remove the carrier sheet 50 from the circuit substrate part leaving the part encircled by the notch intact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a printed circuit board by injection molding, in which a plurality of circuit board sections are connected by a flexible sheet having a wiring section for connecting each circuit section of the circuit board section. .

[0002]

2. Description of the Related Art Electronic equipment contains a plurality of printed circuit boards. These printed circuit boards are three-dimensionally arranged in the case in consideration of the accommodation in the case, the arrangement of parts such as switches, and the heat dissipation of the transistors.

Conventionally, in order to accommodate various kinds of printed circuit boards in a case, they are formed to have a predetermined size, and the circuit portions of the plurality of printed circuit boards are subsequently wired to each other by electric wires or the like. However, in this conventional substrate, there are inconveniences such as the work of wiring between the plurality of substrates is complicated and complicated, the efficiency is low, and there is a possibility of erroneous wiring.

Further, prior to the present invention, the present applicant has proposed an injection molding method for a circuit board, which is capable of integrally forming a circuit pattern together with the injection molding of the board. In this method, a circuit pattern that constitutes a printed circuit is arranged together with a carrier sheet in a cavity having a substrate shape, and the molten resin that constitutes the substrate is injected into the cavity. A substrate is formed integrally with the circuit pattern, and then the carrier sheet on the surface of the molded product is removed to obtain a circuit substrate.

However, even in this manufacturing method, when it is desired to obtain circuit boards having various three-dimensional structures such as a deep box shape, after molding a plurality of circuit boards by this method,
There was a problem that wires had to be wired between these circuits.

[0006]

SUMMARY OF THE INVENTION The present invention provides a manufacturing method by which a printed circuit board having a three-dimensional structure can be obtained at a time and easily by developing and applying the above-mentioned molding method. It is the one we are trying to provide.

[0007]

According to the present invention, a printed circuit board is manufactured by injection molding in which a plurality of circuit board sections are connected by a flexible sheet having a wiring section for connecting each circuit section of the circuit board section. A method, wherein a carrier sheet in which a circuit pattern forming the circuit portion and the wiring portion is formed and a cut is formed in the flexible sheet shape, in a mold cavity having a shape corresponding to the plurality of circuit board portions, The circuit pattern of the circuit section is arranged so as to be inside the cavity, and the molten resin forming the circuit board section is injected into the cavity to form a plurality of circuit board sections integrally with the circuit pattern. , The carrier sheet at the peripheral portion of the circuit board portion in the portion surrounded by the notches is heated by the heat welding heater embedded in the mold to melt the plurality of circuit board portion edge portions. It is allowed, according to the method of manufacturing the printed circuit board and removing the carrier sheet leaving the portion surrounded by then the cut as the flexible sheet from the circuit board unit.

[0008]

The solidification of the molten resin injected into the cavity forms a plurality of circuit board parts integrated with the circuit pattern. The circuit board portion is in a state where the peripheral portion thereof partially overlaps the carrier sheet in the portion surrounded by the cut. Then, the carrier sheet at the peripheral portion of the circuit board portion is heated by the heat welding heater in the mold, so that the carrier sheet is welded to the edge portion of the circuit board portion. After that, if the carrier sheet outside the cut is removed from the circuit board portion using the cut, the carrier sheet in the portion surrounded by the cut is left as a flexible sheet between the plurality of circuit board portions. The flexible sheet provides a desired printed circuit board in which a plurality of circuit board parts are connected. In this printed circuit board, the circuit pattern is formed on each circuit board portion and the flexible sheet portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 is a sectional view of an essential part of an injection molding apparatus used in an embodiment of the manufacturing method of the present invention, FIG. 2 is a front view of an essential part of a carrier sheet in the injection molding apparatus, and FIG. 3 is a print obtained by carrying out the present invention. It is a perspective view of a circuit board.

As shown in FIG. 3, the printed circuit board 10 manufactured according to the present invention includes a plurality of circuit board parts 1.
Flexible sheets 22, 23, 24 having wiring portions 16C, 17C, 18C, 19C for connecting 1, 12, 13, 14, 15 to the respective circuit portions 11C, 12C, 13C, 14C, 15C of the circuit board portion, They are connected by 25.

In the printed circuit board 10, the flexible sheets 22, 22, ... Are joined to the circuit board portions 11, 12, ... by heat welding. Reference numeral J in the drawing indicates the heat welding portion. Show.

FIG. 1 shows a mold open state of an injection molding machine used for manufacturing the printed circuit board 10. This injection molding machine is for temporarily manufacturing the printed circuit board by joining a part of a carrier sheet for arranging a circuit pattern in a mold cavity to a side of a circuit board as a flexible sheet. At the same time, this molding machine can form the component mounting through hole h of the circuit board portion and the circuit board portion mounting through hole H at the same time when the printed circuit board is molded.

As shown in the drawing, in this embodiment, on the side of the fixed die 31 fixed to the fixed die plate 30, cavities 33, 34, 35 having a substrate shape (others are not shown).
Is formed, reference numeral 38 in the drawing denotes an injection nozzle, 39
Is a sprue bush.

The cavity 33 is a printed circuit board 1
0 is for molding the circuit board portion 12, the cavity 34 is for molding the circuit board portion 11, and the cavity 35 is for molding the circuit board portion 14. These cavities 33, 3
4, 35, ... Are provided at predetermined intervals according to the configuration of the printed circuit board 10. Further, if pins are provided upright in the cavity, through holes H, h can be formed in the circuit board portion according to a manufacturing process described later.

A carrier sheet 50 having a circuit pattern 55 forming a circuit portion and a wiring portion is arranged on the movable die 41 fixed to the other movable die plate 40. The movable die 41 is formed in a flat (or curved surface if necessary) plate shape, and the circuit pattern 55 is formed at this predetermined position.
Are arranged together with the carrier sheet 50 so that the circuit pattern is on the cavity side. In the figure, reference numeral 60 is a feed roller for the carrier sheet 50, and 65 is a winding roller.

Further, in order to bond the flexible sheet of the printed circuit board 10 to the circuit board portion by heat welding, the movable die 41 is heat welded to a position corresponding to the flexible sheet bonding position at the peripheral portion of the molded product of the cavity. The heater 45 is embedded.

FIG. 2 shows a part of the carrier sheet 50 used in the present invention. This carrier sheet 50 is P
A circuit pattern 55 made of ET or the like and made of a conductive material such as copper foil is integrally formed. An adhesive layer is formed on the upper surface side of the circuit pattern 55 in order to enhance the adhesiveness with the substrate material resin at the time of molding, and an adhesive layer is formed on the rear surface side of the carrier sheet to prevent the sheet from slipping during molding. A layer may be formed.

The circuit pattern 55 is composed of a circuit section of each circuit board section and a wiring section connected to the circuit section, and corresponds to the printed circuit board 10 shown in FIG. 3 in FIG. The same reference numerals are given. Further, in the figure, the circuit board portions 11, 12, ...
(The heat welding heater 45) is illustrated in an explanatory manner.

In particular, since the present invention utilizes a part of the carrier sheet 50 as the flexible sheets 22, 23, 24, 25, as can be understood from the figure, a pair of heat-welded portions J, J ( The carrier sheet 50 is provided with a cut 51 such as a stitch so as to surround the position of the heat welding heater, that is, in a flexible sheet shape.

Next, manufacturing of a printed circuit board using the above injection molding apparatus will be described. First, as shown in FIG. 1, the circuit pattern 55 is sandwiched between the fixed die 31 and the movable die 41 together with the carrier sheet 50 during injection molding. At this time, the circuit pattern 55 is arranged such that the portion forming the circuit portion is inside the cavities 33, 34, 35 ... And the carrier sheet 50 in the portion surrounded by the notch 51 is partly the cavities 33, 34 ,. It is arranged so as to be located within 35 ... Then, by injecting the molten resin forming the substrate into the cavities 33, 34, 35, ..., A plurality of circuit board portions integrally bonded with the circuit pattern are formed.

On the other hand, the movable heat-welding heater 45 is designed so that the carrier sheet 50 is heat-welded to the circuit board portion.
The sheet is heated to about 0 ° C. or higher, and at this heater position, the carrier sheet portion surrounded by the edge portion of the circuit board portion and the cut 51, that is, the flexible sheet portion 22,
23, ... Are heat-welded together.

After the heat welding, the movable sheet is moved to remove the carrier sheet portion on the surface of the molded article. By removing the carrier sheet, the circuit pattern appears on the surface of the circuit board portion, and at the same time, the flexible sheet portions 22, 23, ...
1 smoothly separated from its outer carrier sheet. Then, the printed circuit board 10 is obtained in which a plurality of circuit board parts are connected by a flexible sheet having a wiring part that connects with each circuit board part of the circuit board part.

[0023]

As described above, according to the manufacturing method of the present invention, a print in which a plurality of circuit board parts are connected by a flexible sheet having a wiring part for connecting with each circuit part of the circuit board part. Since the circuit board can be formed at one time and the wiring between the circuit parts can be performed at the same time, the manufacturing work can be performed very efficiently. In addition, the conventional complicated wiring work is unnecessary, and there is no fear of incorrect wiring.

Further, in the printed circuit board obtained by implementing the present invention, since the respective circuit board portions connected by the flexible sheet can be bent in any directions, various three-dimensional structures can be easily realized. Therefore, the mounting in the case becomes extremely flexible, and a more ideal accommodation state can be realized in consideration of component arrangement, space saving, and the like.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an injection molding apparatus used in an embodiment of a manufacturing method of the present invention.

FIG. 2 is a front view of a main part of a carrier sheet in the injection molding apparatus.

FIG. 3 is a perspective view of an example of a printed circuit board obtained by implementing the present invention.

[Explanation of symbols]

 10: Printed circuit board 11, 12, 13, 14, 15: Circuit board part 11C, 12C, 13C, 14C, 15C: Circuit part 16C, 17C, 18C, 19C: Wiring part 22, 23, 24, 25: Flexible sheet 31: Fixed type 33, 34, 35: Mold cavity 41: Movable type 45: Thermal welding heater 50: Carrier sheet 51: Notch 55: Circuit pattern J: Thermal welding part

Claims (1)

[Claims] 1. A method of manufacturing a printed circuit board by injection molding, the printed circuit board having a plurality of circuit board parts connected by a flexible sheet having a wiring part connected to each circuit part of the circuit board part. And a carrier sheet in which a circuit pattern forming a wiring portion is formed and a cut is formed in the flexible sheet shape, and a circuit pattern of the circuit portion is a cavity in a mold cavity having a shape corresponding to the plurality of circuit board portions. It is arranged so as to be on the inner side, and the molten resin that constitutes the circuit board portion is injected into the cavity to form a plurality of circuit board portions integrally with the circuit pattern, and is surrounded by the notches. The carrier sheet at the peripheral portion of the circuit board portion in the portion is heated by the heat welding heater embedded in the mold to be welded to the plurality of circuit board portion edges, and then surrounded by the notches. Method for manufacturing a printed circuit board and removing the carrier sheet from the circuit board portion portion left as the flexible sheet.