JP2018098448A - Manufacturing method of flexible print circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of FPC capable of manufacturing an FPC using a single type of a copper foil pattern as the base even when the dimensions of the FPCs in a length direction are different from each other.SOLUTION: The manufacturing method of FPC in an embodiment includes: a cover film bonding step SB7 to bond a cover film 5 to a base film 3 of an FPC 1; an outer shape processing step SB9 to separate each FPC 1 from the base film 3; and an opening step SB6 of a guide hole 8 used for carrying out the outer shape processing. Before the cover film bonding step SB7, the opening step SB6 of the guide hole 8 is carried out, and subsequently the cover film bonding step SB7 is carried out using the guide hole 8 and then followed by the outer shape processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a flexible printed circuit board.

  Conventionally, in selecting a source driver IC (hereinafter referred to as S-IC) that is mounted on a liquid crystal panel of a liquid crystal display device using COG (Chip On Glass) technology, the resolution of the liquid crystal panel, that is, the total number of source wirings is determined. Correspondingly, in consideration of the number of output terminals of the S-IC, selection has been made so that the remainder of the output terminals does not occur.

  However, in recent years, S-ICs using a large number of output terminals have become widespread (see paragraph 0010 of Patent Document 1), and the total number of output terminals of one or a plurality of S-ICs differs from the total number of source wirings of the liquid crystal panel. In this case, for example, even if there is a surplus in the output terminal of the S-IC, the same S-IC is often used for a low-resolution to high-resolution liquid crystal panel.

  In addition, a flexible printed circuit board (hereinafter referred to as FPC) that serves as a bridge when sending a signal or a power supply to the S-IC from the circuit board side via the liquid crystal panel side connection terminal is well known (Patent Document 2). FIG. 1). Conventionally, an FPC has been newly designed and manufactured for each design of a liquid crystal display device in response to various S-IC specifications with different S-IC input terminal arrangements. However, as described above, with the widespread use of multi-output S-ICs, the standardization of the S-ICs has progressed, and the arrangement of FPC connection terminals can also be unified. As a result, FPCs arranged between the circuit board side and the liquid crystal panel are increasingly used as FPCs having the same external dimensions in the width direction.

JP 2012-252216 A JP 2003-337550 A

  On the other hand, depending on the required specifications and product concept, the thickness and the like may be different for each liquid crystal display device. In this case, the FPC for connecting between the circuit board and the liquid crystal panel has an excessive or insufficient outer length in the length direction of the FPC when assembling the backlight and the liquid crystal panel even if the connection terminal arrangement and the outer dimension in the width direction are the same. A new FPC design needs to be performed. (Here, “the length direction of the FPC” means a direction along the wiring in the FPC, and “the width direction of the FPC” means the arrangement direction of the connection terminals.)

  Thus, when FPC design is performed for each new development of a liquid crystal display device, the cost of FPC increases due to an increase in development cost or an increase in the number of FPC types.

  Therefore, in order to solve the above problems, even if the dimensions in the FPC length direction are different, the base wiring pattern can be handled with a single type, which is excellent in productivity and low cost. There is a need for a manufacturing method.

  The FPC manufacturing method according to the present invention includes a cover film bonding step for bonding a cover film to a base film of the FPC, an outer shape processing step for separating the FPC from the base film, and guide holes for the outer shape processing. An opening step of the FPC, wherein the guide hole opening step is performed before the cover film bonding step, the cover film bonding step is performed using the guide hole, and then the outer shape A processing step is performed.

  In the present invention, by performing the guide hole opening step before the cover film bonding step, the cover film can be bonded to the base film with high accuracy, and an FPC having a desired FPC length can be manufactured.

FIG. 6 is a process diagram showing a manufacturing process of the FPC according to the first embodiment. It is the schematic which showed the imposition state in the worksheet of FPC. 3A and 3B are a schematic diagram and a cross-sectional view illustrating a worksheet in the middle of manufacturing the FPC according to the first embodiment. 2A and 2B are an external view and a cross-sectional view of the FPC according to the first embodiment. FIG. 6 is an outline view and a cross-sectional view of an FPC according to Embodiment 2.

Embodiment 1 FIG.
Embodiments of the present invention will be described below with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In the following description, the same reference numerals indicate substantially the same contents.

  FIG. 1 shows an example of an FPC manufacturing process according to the first embodiment. 1 (a) shows an example of a conventional FPC manufacturing process. A base substrate is manufactured by bonding a copper foil to a film-like insulating material (base film) made of polyimide or the like. Step SA1, Step SA2 for forming a photoresist layer on the copper foil, Step SA3 for exposing the photoresist with ultraviolet light and then developing, Step SA4 for etching the copper foil to form a wiring pattern, Step SA4 on the copper foil Step SA5 for removing the remaining photoresist layer, Step SA6 for bonding the cover film on the copper foil other than the terminal portion for preventing corrosion of the copper foil, Step SA7 for plating the copper foil for the terminal portion with gold, etc. For the next outer shape processing, a step SA8 for making a guide hole, an outer shape processing step SA9 for dividing and dividing into individual FPCs, an electrical check step SA10 for wiring patterns, After pasting the reinforcement on the rear surface of the terminal portion, and the necessary printing a step SA11 of the order in FPC is manufactured in general.

  As shown in FIG. 2, in the manufacturing process of the FPC 1, a plurality of FPCs 1 are surfaced on a base film 3 called a worksheet of a predetermined size and cut into individual pieces in the outer shape processing step SA9. Is common. This outer dimension of the worksheet is referred to as a worksheet size. In each process from SA1 to SA8, this work sheet is left as it is, and each process is flowed. In the outer shape processing process SA9, for example, the FPC 1 is separated into a plurality of FPCs 1 with the outer shape shown by broken lines in FIG. In the example of FIG. 2, the FPC 1 is divided into eight pieces.

  Next, an example of a manufacturing process of the FPC 1 according to the first embodiment is shown in FIG. In the present embodiment, since the base substrate manufacturing process SB1 to the photoresist layer peeling process SB5 are the same as the FPC manufacturing process example (FIG. 1A) in the above-described conventional technology, detailed description is given here. I do not explain.

  Here, FIG. 3 shows the FPC worksheet base substrate 4 according to the first exemplary embodiment. In the present embodiment, in the base substrate manufacturing process SB1 of the worksheet, as shown in FIG. 3A, the wiring pattern 2 can be extended and formed without depending on the length of the FPC 1. Then, the dimension in the length direction is determined to be large (the maximum dimension required). The X direction in the figure is the “FPC width direction” described above, and the Y direction is the “FPC length direction”.

  Next, unlike the prior art, in the present embodiment, a guide hole opening process SB6 for external processing is performed. The guide hole 8 is used as an alignment guide when the cover film 5 is attached to the base substrate 4 in the next cover film bonding step SB7. In the example illustrated in FIG. 3A, guide holes 8 are formed in the four corners of the base substrate 4. Next, the copper foil part to which the cover film 5 is not affixed is plated as the connection terminal 7 (SB8).

  After that, as in the conventional case, the outer shape processing (cutting) step SB9, the electrical check step SB10, and finally the step SB11 for attaching the reinforcing material and printing are performed.

  Here, in the first embodiment, as shown in FIG. 3B, which is a cross-sectional view taken along line AA ′ in FIG. 3A, a pair of input / output terminals of the FPC 1 is connected. As a conductor (copper foil) connected to each other, a plurality of linear wiring patterns parallel to the outer shape of the FPC 1 in the length direction are arranged. In FIG. 3B, reference numeral 2 denotes the wiring pattern of copper foil, and reference numeral 4 denotes a base substrate.

  As a feature of the wiring pattern 2, a cover film 5 having a length (dimension in the Y direction in the drawing) suitable for a position to be cut at a desired length of the FPC 1 (ie, a desired length between connecting terminals) is provided. Even if the length of the FPC 1 is different by cutting at the desired FPC length in the subsequent outline processing (cutting) step (SB9), the length of the FPC 1 (in the Y direction) It becomes easy to manufacture FPCs 1 having different external dimensions. As is clear from comparison between the first FPC outline indicated by the broken line in FIG. 3A and the second FPC outline indicated by the alternate long and short dash line, the same base substrate 4 is used. First, the outer shape, particularly the length, can be easily changed according to the application of the FPC 1.

  FIG. 4 shows an outline view (FIG. 4 (a)) of the FPC 1 separated through the outline processing (cutting) step SB9 and a cross-sectional view between BB ′ in FIG. 4 (FIG. 4). (B)). In FIG. 4B, reference numeral 2 denotes a copper foil wiring pattern, reference numeral 4 denotes a base substrate, and reference numeral 5 denotes a cover film. The cover film 6 attached to the back surface side with the base film 3 interposed between the connection terminal portions 10 arranged at the end portions of the FPC 1 serves to reinforce the connection terminals 7 from the back side.

  As described above, by setting the dimension in the length direction of the worksheet size of the base substrate 4 of the FPC 1 larger and performing the guide hole opening process SB6 before the cover film bonding process SB7, the desired FPC 1 In order to enable cutting by length, the cover film 5 and the cover film 6 having a length opposite to the length of the FPC 1 can be bonded to each other at a predetermined position with high accuracy with the guide hole 8 as a reference. Even when the required lengths of the FPCs 1 are different, it is possible to manufacture the FPCs 1 having different FPC external lengths by using one wiring pattern 2.

  As a result, since one wiring pattern 2 can be manufactured, a light shielding mask (not shown) for creating a wiring pattern can be reduced, mask management becomes easy, and as a result, costs can be reduced.

  In the above-described first embodiment, as shown in FIG. 3A, the guide hole opening process SB6 has shown the example in which the guide holes 8 are opened at the four corners. It is not necessary to limit the arrangement of the holes 8 to the four corners, and as long as alignment is possible, it may be anywhere in the blank area (the portion that is discarded as an FPC in the outer shape processing (dividing) step SB9). .

Embodiment 2. FIG.
FIG. 5 is an outline view and a cross-sectional view of the FPC according to the second embodiment, and is a modification of the individual side of the FPC 1 illustrated in FIG. 1 of the first embodiment. As illustrated in FIG. 5, cover film bonding guide holes 8 are formed in two places outside the wiring area of the FPC 1. These guide holes 8 are drilled in the guide hole opening step SB6 as described in the first embodiment. At the same time, four bonding alignment holes 9 are made in the four corners of the FPC 1.

  In the case of the guide hole opening step SB6 described in the first embodiment, the use opportunity of the guide hole 8 was the cover film pasting step SB7 and the outer shape processing (individualization) step SB9. There was no problem even if the guide hole 8 was made based on the outer shape of the worksheet. However, in the second embodiment, the alignment holes 9 arranged at both ends of the connection terminal area are aligned (aligned with the connection terminals) when the circuit board or the display panel (not shown) and the FPC 1 are attached. ) To be used as an alignment mark, high positional accuracy with respect to the connection terminal 7 of the FPC 1 is required.

  In that case, a parent alignment mark may be formed at a plurality of locations in a suitable area of the blank area in the base substrate 4 with a copper foil pattern. For example, alignment marks (not shown) can be formed in a blank portion in a row in parallel with the wiring pattern 2 at regular intervals. Since the parent alignment mark can be formed in the etching step SB4 simultaneously with the wiring pattern 2 and the connection terminal 7 pattern, the parent alignment mark has high positional accuracy with the connection terminal 7 pattern. If alignment is performed with the parent alignment mark and the guide hole opening step SB6 is performed, the alignment holes 9 arranged at both ends of the connection terminal portion region can also have high positional accuracy with the connection terminal 7.

  The second embodiment is a solution to the concern that occurs in the first embodiment, that is, since the length of the FPC 1 is not determined in advance, it is difficult to arrange the mounting alignment marks.

  In the second embodiment described above, as illustrated in FIG. 5A, the guide hole 8 is opened outside the wiring area of the FPC 1 in the guide hole opening step SB6. There is no need to limit the arrangement of the holes 8, as long as the alignment for attaching the cover film is possible, it may be anywhere in the blank area, and further, the guide hole 8 dedicated for attaching the cover film may be formed. It is not essential and may be used also as the alignment hole 9. In other words, the guide hole 8 may not be provided, and the alignment of the cover film may be performed in the alignment hole 9.

  In the above description of the image display apparatus, a liquid crystal display device is adopted as an example of the image display device, and the embodiment thereof is shown. However, the image display device does not need to be a liquid crystal display device. Even in an image display device that employs a display device, a MEMS (Micro Electro Mechanical System) display device, or the like, there are cases where various FPCs having different lengths are required for each model, and the present invention can be implemented at that time. Of course.

1 FPC
2 Wiring pattern 3 Base film 4 Base substrate 5, 6 Cover film 7 Connection terminal 8 Guide hole 9 Alignment hole 10 Connection terminal part

Claims (3)

A cover film bonding process for bonding the cover film to the base film of the flexible printed circuit board;
An outer shape processing step for separating the flexible printed circuit board from the base film,
In the manufacturing method of the flexible printed circuit board having the step of opening the guide hole at the time of the outer shape processing,
Perform the guide hole opening step before the cover film bonding step,
The cover film bonding step is performed using the guide hole,
Thereafter, the outer shape processing step is performed,
A method for producing a flexible printed circuit board. In the step of opening the guide hole,
The method for manufacturing a flexible printed circuit board according to claim 1, wherein an opening hole is formed adjacent to a connection terminal portion of the flexible printed circuit board.   The said opening hole is a manufacturing method of the flexible printed circuit board of Claim 1 or 2 which is an alignment mark for the alignment of the said flexible printed circuit board and a connection object board | substrate.

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