JP3233161B2 - Flexible printed circuit board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible printed circuit board, and more particularly, to a flexible printed circuit board which is thin, highly flexible and has a relatively small shape.

[0002]

2. Description of the Related Art A flexible printed circuit board is generally manufactured as follows. That is, the copper foil surface of the copper-clad flexible circuit board is subjected to exposure, pattern formation, etching, and the like to form a flexible circuit. Next, the copper foil is left exposed at the part where component mounting or wiring or connection with a connector is performed, and a coverlay is applied to other parts. Such a flexible printed circuit board is rarely manufactured one by one, and it is common to form a plurality of products at the same time, apply a coverlay, and then separate and use the products by punching or the like.

By the way, electronic devices using such a flexible printed circuit board have been increasingly reduced in size and weight in recent years. Accordingly, relatively small products are being used.

If the thin and small product is separated into individual products, the workability of handling the product is extremely poor. Therefore, various devices for handling a plurality of products collectively have been studied.

For example, JP-A-60-31290 and JP-A-60-5
As shown in No. 2082, leave one part connected so that each product does not fall apart when punching a circuit, paste it on a base sheet with adhesive, and cut and remove the connected part Method, as in JP-A-2-39489 and JP-A-2-39490, paste on a release sheet with adhesive before punching the product, and punch the product from the back of the product so that the release sheet is not punched , A method for removing unnecessary portions,
After temporarily fixing the product to the release sheet using a double-sided adhesive tape with different adhesive strength on the front and back as in 2-39491, the product is punched from the back of the product so that the release sheet is not punched out, unnecessary parts And the like.

[0006]

A method which has been conventionally studied as a device for handling a plurality of products collectively has the following problems. JP-A-60-31290, JP-A-60-31290
The method of No. 60-52082 is a complicated process in which a part of the connecting part is left in the first punching, and after bonding to a base sheet or the like with an adhesive, the connecting part is cut again by punching out the connecting part. And two types of punching dies are required. As described above, electronic devices using such a flexible printed circuit board have been increasingly reduced in size and weight in recent years. As a single product, a relatively small one is used, and strict requirements for dimensional accuracy are required. Has become. Therefore, the requirements for the dimensional accuracy of the mold are strict, and the cost of a mold that can meet such a requirement is high. Therefore, a method that requires two different kinds of molds has a problem in that respect.

[0007] In the method disclosed in JP-A-2-39489 and JP-A-2-39490, before punching a product, the product is pasted on a release sheet with an adhesive, and the circuit is punched from the surface of the circuit so that the release sheet is not punched. However, there is a problem in that the unnecessary portion is removed, but the entire flexible printed circuit board is stuck to the slightly adhesive sheet, and it is difficult to peel off the edges when the products are used one by one at the time of mounting. In particular, recently, there has been an increase in a form in which an end is inserted into a connector, and when the end is wrinkled or broken at the time of peeling, there is a risk of causing a fatal quality defect such as poor contact of a product. .

The method of Japanese Patent Application Laid-Open No. 2-39491 discloses a method in which a circuit is temporarily fixed to a base sheet using a double-sided adhesive tape having different adhesive strengths on the front and back sides, and the circuit is designed so that the base sheet is not punched from the back side of the circuit. This is a method of punching and removing unnecessary portions, but it is very troublesome to temporarily fix the product to the base sheet using a double-sided adhesive tape having different adhesive strengths on the front and back surfaces in advance. In other words, as described above, such flexible printed circuit boards require strict dimensional accuracy, and the same dimensional accuracy is required for the temporary fixing position before punching, and in consideration of this point, double-sided adhesive tape is used. It turns out that the temporary fixing is a very difficult process.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a thin and small flexible printed circuit board is not separated one by one at the time of inspection or transportation, but a plurality of circuits are handled collectively and at the time of mounting, one product at a time. The object of the present invention is to improve the conventional complicated and accurate method of detecting problems in the method of separating and using, and to obtain a flexible printed circuit board which is easy, accurate and stable in quality. .

That is, the present invention relates to a flexible printed circuit board in which a plurality of required flexible printed circuit boards to be formed into a product are adhered on a base sheet to which an adhesive is applied. Parts of the flexible printed circuit board that are not likely to be wrinkled or broken, such as parts for mounting parts, parts for wiring, parts for inserting connectors, etc., should not be selectively adhered to the base sheet. In order to adhere the part on the base sheet, the part of the required flexible printed circuit board to be a product, the part to mount the parts, the part to wire,
A release film that is not coated with an adhesive is selectively provided between the base sheet and a part where wrinkling or breakage is difficult to occur, such as a part where a connector is inserted. The present invention relates to a flexible printed circuit board and a method for manufacturing the same. Then, the manufacturing method is such that a release film not coated with an adhesive, which has a slit at a predetermined position, is bonded to a base sheet coated with the adhesive, and a required flexible printed circuit board to be a product is formed. , Leave the release film of the part that does not need to be adhered as it is, and selectively remove only the release film of the part necessary for temporary fixing of the required flexible printed circuit board that will become a product And a step of adhering a plurality of required flexible printed circuit boards to be products to a base sheet. In the other steps such as forming a circuit, a conventionally well-known method such as etching is appropriately employed.

[0011]

The slit of the release film can be easily and accurately placed at a predetermined position. The release film is selectively removed, and only the necessary portion of the flexible printed circuit board is temporarily fixed. Edges and the like that are not likely to be wrinkled or broken during the peeling can be left unadhered, so that a flexible printed circuit board that is easy to peel and has no fear of causing quality defects can be obtained.

[0012]

1 to 5 show an embodiment of the present invention. That is, FIG. 1 shows a flexible printed circuit board (a group of a plurality of products 2), which is formed by exposing, phenomenon, and etching the copper foil surface of a copper-clad flexible printed circuit board obtained by laminating a film such as a polyimide film and a copper foil. To form a plurality of flexible circuits, the copper foil surface of the part 11 for component mounting and the part 10 for connection with wiring or a connector is preliminarily formed with holes at predetermined positions so as to be exposed. It is obtained by laminating an opened film, for example, a coverlay film made of polyimide on the copper foil surface. FIG. 2 shows a cross section of FIG. 1, wherein 6 is a polyimide film, 3 is a circuit, and 4 is a coverlay film.

Next, using a 125 μm polyester film as a base sheet, an adhesive is applied thereon,
Further, a 10 μm polyester film was bonded for release. For release, not only polyester film but also paper or the like can be used. A slit is formed at a predetermined position of the polyester film for release (for example, as shown at 12 in FIG. 3), and a portion where the flexible printed circuit board and the base sheet are to be brought into close contact with each other is selected. Thus, the release film can be held or removed. FIG. 4 shows a cross section immediately before the flexible printed circuit board and the base sheet are brought into close contact with each other. 8 shows a base sheet coated with an adhesive,
Like the part where components are mounted on the flexible printed circuit board and the part where wiring and connectors are connected,
The part where wrinkles and breaks do not occur when detached from the base sheet is shown as 7 with the release film remaining. FIG. 3 shows a state in which the flexible printed circuit board and the base sheet are overlaid after selecting the portion to be adhered and the portion not to be adhered.

FIG. 5 shows a seal blade 9 having the same shape as one product.
5 shows a state in which the substrate is penetrated from the side of the flexible printed circuit board and half cutting is performed so that the blade is inserted into about half of the base sheet.

After the half-cut, the remaining portion from which the product has been punched out is peeled off, so that each flexible printed circuit board is separated from the product one by one and becomes independent and partially fixed to the base sheet. become. Inspection, transportation, etc. are performed in a state where a plurality of circuits are bundled together, and when mounting, one product can be easily removed from the base sheet, handling is easy, and component mounting parts, wiring or connectors No wrinkles or breaks occurred in the connection part to the, and the work reliability was improved.

[0016]

As described in the embodiments, according to the present invention, the portion where the flexible printed circuit board and the base sheet are to be brought into close contact with each other and the portion where the flexible printed circuit board is not to be brought into close contact are easily and accurately selected and temporarily selected. Can be stopped. Therefore, when handling a small-sized flexible printed circuit, inspection, transportation, etc. are performed in a state in which a plurality of circuits are grouped together, and when mounting, one circuit can be easily removed from the base sheet. The work efficiency is good, and wrinkles and breaks do not occur in the parts mounting part, the wiring part, or the part inserted into the connector, so that highly reliable work can be performed.

[Brief description of the drawings]

FIG. 1 shows a flexible printed circuit board (a group of a plurality of circuits).

FIG. 2 shows a cross section of FIG.

FIG. 3 shows a state in which a flexible printed board and a base sheet are bonded together.

FIG. 4 shows a cross section immediately before bonding a flexible printed board and a base sheet.

FIG. 5 shows a half-cut state.

[Brief description of reference numerals] 1: Flexible printed circuit board 2: One product 3: Circuit cross section 4: Coverlay film 6: Base film (for example, polyimide film) 7: Release film 8: Base sheet with adhesive

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-31290 (JP, A) JP-A-60-52082 (JP, A) JP-A-3-4586 (JP, A)

Claims (4)

(57) [Claims] 1. A required flexible printed circuit board to be a product in a flexible printed circuit board in which a plurality of required flexible printed circuit boards to be a product are adhered on a base sheet coated with an adhesive. The parts where wrinkles or breaks do not occur, such as parts for mounting parts, parts for wiring, parts for inserting connectors, etc. are not selectively adhered to the base sheet, and other parts are Parts that are not susceptible to wrinkles and breaks, such as parts for mounting, wiring, and connector insertion, on the required flexible printed circuit board that should become a product to adhere to the sheet And a release film to which no adhesive is applied is selectively provided between the flexible printed circuit board and the base sheet. Board. 2. The “release film” according to claim 1,
The flexible printed circuit board according to claim 1, wherein the flexible printed circuit board is a "polyester film or paper". 3. An adhesive-free base film coated with a pressure-sensitive adhesive and a release film not coated with a pressure-sensitive adhesive is bonded to a base sheet coated with the pressure-sensitive adhesive to form a flexible printed circuit board. The part of the release film that is troublesome is left attached, and only the part of the release film that is necessary for temporary fixing of the required flexible printed circuit board to be a product is selectively removed, A method of manufacturing a flexible printed circuit board, comprising a step of adhering a plurality of required flexible printed circuit boards to be products to a base sheet. 4. The “release film” according to claim 3,
The method for manufacturing a flexible printed circuit board according to claim 3, wherein the method is a “polyester film or paper”.