KR20220040299A - Installation Structure of Flexible Printed Circuit Board - Google Patents

Abstract

An object of the present invention is to provide a flexible printed circuit board installation structure capable of solving the problem that a pattern fuse is deprived of heat by injection molding and the melting time becomes longer. The present invention relates to an installation structure of a flexible printed circuit board including a pattern fuse, and the pattern fuse is formed of a conductive pattern to electrically connect two adjacent circuits, wherein the flexible printed circuit board includes a metal pattern layer including a conductive pattern layer including the pattern fuse; and a film layer attached to one surface of the metal pattern layer, and includes: a flexible printed circuit board; an injection-molded product disposed spaced apart from the flexible printed circuit board; and an air layer forming structure disposed between the flexible printed circuit board and the injection-molded product and fixing the flexible printed circuit board to the injection-molded product, wherein the air layer is formed between the flexible printed circuit board and the air layer forming structure.

Description

Installation Structure of Flexible Printed Circuit Board

The present invention relates to a flexible printed circuit board having a patterned fuse, and more particularly, to an installation structure of a flexible printed circuit board including a patterned fuse in which a fuse is formed in a metal circuit pattern and the pattern is destroyed and disconnected when an overcurrent is applied will be.

Printed Circuit Board (PCB) or Flexible Printed Circuit Board (FPCB, hereinafter referred to as “printed circuit board” or “PCB”) is a standardized method for fixing and connecting a number of electronic components. It is a circuit board on which the wiring made for this purpose is patterned. A PCB can mechanically and electrically combine a plurality of circuits, and through this, an electrical product can be miniaturized and lightened. In addition, circuit characteristics are stabilized, there is no fear of miswiring, and the production cost is low. Due to these advantages, PCBs and FPCBs are used in various fields, and recently, they are becoming essential components for all electronic devices.

On the other hand, when a plurality of electrical components are connected and used, when an overcurrent occurs due to a failure, malfunction, or external factor of an electrical component, there is a risk that the plurality of connected electrical components may be damaged together. Therefore, in order to protect a plurality of electrical components, it is common to install a fuse on the power supply side of the circuit to break the current when an overcurrent occurs so that the mounted fuse is destroyed.

1 is a photograph showing a conventional chip fuse mounted as a fuse, and FIG. 2 is a cross-sectional view of the fuse of FIG. 1 . Referring to this, in the related art, a metal pattern layer (1a), a film layer (1b), an adhesive (1c) for attaching the metal pattern layer and the film layer are laminated on the circuit pattern in the FPCB (1), a surface mount type component (SMD) , Surface-Mount Devices) was formed, and an SMD-type chip fuse (2) was soldered on the pad to prevent damage to the circuit pattern or the substrate due to overcurrent.

However, when the chip fuse (2) is mounted, the cost of the chip fuse raw material value and the soldering and coating work related to the mounting is required, which increases the cost of the product. In addition, in order to apply the chip fuse, it is necessary to secure a space for the chip fuse and soldering, so that the size of the printed circuit board increases, which may cause additional cost increases and limitations in miniaturization.

Therefore, research on a pattern fuse capable of omitting the conventional chip fuse land and functioning as a fuse is being actively conducted. The pattern fuse 20 is a circuit pattern that functions as a fuse, and refers to a fuse unit applied to a printed circuit board. In order to increase space utilization, as shown in FIG. 3 , the bent part 21 and the straight part 22 are alternately formed. is becoming

The pattern fuse eliminates the conventional chip fuse and eliminates the process for bonding the chip fuse, thereby reducing the cost. It is not, so it is difficult to develop.

In particular, as shown in FIG. 4 , the PCB 1 including the pattern fuse 20 is attached to and fixed to the injection molded product 4 which is a part of the product when applied to an actual product. There is a problem in that it conducts quickly through 4) and the fusing time is long, which does not satisfy the requirements of the pattern fuse (2). In particular, in the case of a flexible PCB (FPCB), since it is formed flexibly as a whole, there is an unavoidable problem of being in close contact with the injection-molded product.

The present invention is to solve the problems of the prior art as described above, and specifically, to provide an installation structure of a flexible printed circuit board that can solve the problem that the pattern fuse loses heat by the injection molding and the cutting time becomes longer The purpose.

An embodiment of the present invention provides an installation structure of the following flexible printed circuit board in order to solve the above problems.

The present invention provides an installation structure of a flexible printed circuit board including a patterned fuse, wherein the patterned fuse is formed in a conductive pattern to electrically connect two adjacent circuits, and the flexible printed circuit board includes a conductive pattern including the patterned fuse. A metal pattern layer including a layer and a film layer attached to one surface of the metal pattern layer, the flexible printed circuit board; an injection molded product disposed to be spaced apart from the flexible printed circuit board; and an air layer forming structure disposed between the flexible printed circuit board and the injection-molded product and fixing the flexible printed circuit board to the injection-molded product. Including, characterized in that the air layer is formed between the flexible printed circuit board and the air layer forming structure.

In addition, the air layer forming structure is characterized in that any one of an epoxy resin, a foam foamed with a resin, and an adhesive tape.

In addition, it is characterized in that grooves are formed in the surface facing the film layer of the injection molded product.

In addition, a rib is protruded from the surface of the injection-molded product toward the film layer to extend along the surface of the injection-molded product.

In addition, the rib is characterized in that it is formed to extend in a closed figure shape.

In addition, the rib is characterized in that the protrusion is formed to form a concave curved surface along the inner edge of the figure shape.

In addition, the rib is characterized in that one side is formed at a position in contact with one side of the air layer forming structure.

According to the problem solving means of the present invention as described above, various effects including the following items can be expected. However, the present invention is not established only when exhibiting all of the following effects.

According to the present invention, by forming an air layer between the portion where the pattern fuse is formed and other components of the product, heat generated from the pattern fuse can be prevented from easily dissipating. Accordingly, there is an effect that the fusing time of the pattern fuse is shortened and the performance is improved.

This was confirmed by the experiment, and the experimental results are as follows.

division PATTERN FUSE CLOSE TYPE Pattern Fuse OPEN TYPE sample 1 sample 2 sample 3 sample 4 sample 5 sample 1 sample 2 sample 3 sample 4 sample 5 stick 9.41 8.93 10 seconds
More than 10 seconds
More than 10 seconds
More than 10 seconds
More than 6.16 6.7 10 seconds
More than 10 seconds
More than air layer 3.14 2.84 2.75 3.56 3.67 1.72 2.7 4.21 4.36 3.29

- Specimen conditions: pattern length (30~60mm), current capacity (1.5~2A)

- Unit: Seconds

In the above experiment, the melting time of the pattern fuse was measured in a state in which the injection-molded product and the FPCB were in close contact (classified as “close”) and in a state in which an air layer was formed between the molded product and the FPCB (classified as “air layer”). As a result of the experiment, it was confirmed that the melting time of the pattern fuse was reduced by about 50% or more in the state in which the air layer was formed.

division air gap distance 0.3mm 0.5mm 1.0mm 2.0mm 3.0mm sample 1 2.16 2 1.98 1.82 1.8 sample 2 2.56 2.51 2.24 2.14 2.1 sample 3 2.86 2.41 1.94 1.88 1.84

- Specimen conditions: pattern length (30~60mm), current capacity (1.5~2A)

- Unit: Seconds

In the above experiment, the fusing time of the pattern fuse was measured according to the distance (refer to the h of FIG. 6 ) at which the injection-molded product and the FPCB were separated by an air layer. As a result of the experiment, it was confirmed that the shorter the fusing time was as the air spaced apart distance increased, and this trend is shown in the graph of FIG. 11 .

1 is a photograph showing that a chip fuse is mounted as a conventional fuse;
Fig. 2 is a cross-sectional view of the fuse of Fig. 1;
3 is a plan view schematically showing a patterned fuse;
4 is a cross-sectional view of the pattern fuse of FIG. 3;
5 is a CLOSE type cross-sectional view of the first embodiment of the present invention;
6 is an OPEN type cross-sectional view of the first embodiment of the present invention;
7 is an exploded perspective view of FIG. 5;
8 is a cross-sectional view of a second embodiment of the present invention;
9 is a cross-sectional view of a third embodiment of the present invention;
10 is an exploded perspective view of FIG. 9;
11 is a graph showing the melting time according to the separation distance of the air layer.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

The present invention relates to a flexible printed circuit board (1), and the following description may be applied to a general printed circuit board (PCB) as well as a general flexible printed circuit board (FPCB). Hereinafter, the present invention will be described based on a flexible printed circuit board (FPCB).

5 is a CLOSE-type cross-sectional view of the first embodiment of the present invention, FIG. 6 is an OPEN-type cross-sectional view of the first embodiment of the present invention, and FIG. 7 is an exploded perspective view of FIG. As shown in these figures, in the first embodiment of the present invention, an adhesive 1c for adhering the metal pattern layer 1a, the film layer 1b, the metal pattern layer 1a and the film layer 1b. Including FPCBs, including Both ends of the metal pattern layer 1a of the FPCB are electrically connected to adjacent circuits, and a pattern fuse 20 in which curved curved portions 21 and straight straight portions 22 are alternately formed is formed in the central portion. . In the drawing, it can be seen that the portion in which the pattern fuse 20 is formed has a height lower than that of the circuits at both ends. This is to increase the resistance by narrowing the cross section of the pattern fuse 20 . As the cross section of the pattern fuse 20 is formed to be small, the adhesive 1c having adhesiveness may permeate through the step formed by the pattern fuse 20 so that the film and the pattern fuse 20 are closely adhered to each other.

The CLOSE type pattern fuse 20 of FIG. 5 has film layers 1b formed on both surfaces of the metal pattern layer 1a, and the OPEN type pattern fuse 20 of FIG. 6 is formed on both sides of the metal pattern layer 1a. The film layer 1b is formed, and the film of the pattern fuse 20 is opened on the surface exposed to the outside, and the opened portion is protected by a separate cover 5 .

The installation structure of the flexible printed circuit board (1) of the present invention relates to a structure for installing the FPCB on one side of the product, wherein the installation part of the product is generally formed of the injection molded product (4). Therefore, in the present specification, the part on which the FPCB is to be installed is referred to as an injection molded product (4). The present invention is characterized in that the air layer (A) is formed between the FPCB and the injection-molded product (4), and is distinguished from the conventionally flexibly formed FPCB in close contact with the injection-molded product (4) and fixed.

The present invention forms an air layer (A) by arranging the air layer-forming structure 50 between the FPCB and the injection product 4, and allowing the FPCB and the injection product 4 to be spaced apart (h) from each other by the air layer formation structure 50. . The air layer forming structure 50 may be formed to protrude as a part of the injection-molded product 4 , or may be manufactured as a separate member and adhered to the injection-molded product 4 . In this case, the air layer forming structure 50 may be formed of FR4, which is one of the epoxy resin materials, a resin foamed foam (FORM), or a tape (TAPE). The FPCB can be installed by attaching the air layer forming structure 50 to one side of the injection-molded product 4 and attaching the FPCB to the other side of the opposite side.

Furthermore, as shown in FIG. 7 , the air layer A is preferably formed in the portion where the pattern fuse 20 is formed. Since the general circuit connected by the pattern fuse 20 is rather disadvantageous when fused, the heat generated in the circuit is rapidly dissipated through the injection molded product 4 while the heat generated from the pattern fuse 20 is dissipated by the air layer (A). This is because it may be concentrated in the pattern fuse 20 without being generated.

Hereinafter, each configuration of the second embodiment of the present invention will be described. In the description of the second embodiment, the same reference numerals are used for the same parts as those of the first embodiment, and the description is omitted.

8 is a cross-sectional view of a second embodiment of the present invention. Referring to FIG. 8 , an air layer forming part 40 is formed in the injection-molded product 4 to form an air layer A between the FPCB and the injection-molded product 4 . The air layer forming part 40 is formed in the shape of a groove 41, and the groove 41 is concave in a surface facing the FPCB. It is advantageous to prevent heat dissipation of the pattern fuse 20 if the position, shape, and width of the groove correspond to the position, overall size, and width of the pattern fuse 20 including the bent portion 21 and the straight portion 22 .

In the case of the second embodiment, the air layer forming structure 50 may be included, and the air layer forming structure 50 may be provided to simply serve as an adhesive as shown in the drawing.

Hereinafter, each configuration of the third embodiment of the present invention will be described. In describing the third embodiment, the same reference numerals are used for the same parts as those of the first embodiment, and the description is omitted.

9 is a cross-sectional view of a third embodiment of the present invention, and FIG. 10 is an exploded perspective view of FIG. 9 and 10 , an air layer forming part 40 is formed in the injection-molded product 4 to form an air layer A between the FPCB and the injection-molded product 4 . The air layer forming unit 40 is formed in the shape of a rib 42 , and the rib 42 may protrude from one surface of the injection-molded product 4 toward the FPCB and be formed to extend along one surface. A plurality of ribs 42 may be formed in the shape of a line, or may be formed in the shape of a closed figure as shown in FIG. 10 . The position, shape, and width of the rib 42 correspond to the position, overall size and width of the pattern fuse 20 including the bent portion 21 and the straight portion 22 , which is advantageous in preventing heat dissipation of the pattern fuse 20 . Do.

In addition, it is preferable that the rib 42 protrudes so as to form a concave concave surface 43 along the inner edge of the above-described figure shape. As the heat is reflected through the concave surface 43, the shape of the air layer (A) has the effect that it becomes easier to confine the heat.

Furthermore, the rib 42 may be formed in a position and size such that one outer surface of the rib 42 can be in contact with one side of the air layer forming structure 50 . This is effective in confining the air formed in the air layer (A), and furthermore, when the FPCB in which the pattern fuse 20 is formed is separately manufactured and the circuit is connected with the pattern fuse 20, the air layer forming structure 50 and the rib ( 42) can easily align the FPCB to the correct position, improving workability.

Although each embodiment has been described separately in this specification, embodiments that can be derived by combining each embodiment also fall within the scope of the present invention.

The above description is merely illustrative of the technical idea of the present invention, and various modifications and variations are possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. The scope of protection should be interpreted by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

1 Printed circuit board 1a metal pattern layer
1b film layer 1c adhesive
2 Chip fuse 3 Solder part
4 injection molding 20 pattern fuse
21 Bend 22 Straight
A Air layer 40 Air layer forming part
41 home 42 rib
43 Concave surface 50 Air layer forming structure

Claims (7)

An installation structure of a flexible printed circuit board including a patterned fuse, comprising:
The pattern fuse is formed in a conductive pattern to electrically connect two adjacent circuits,
The flexible printed circuit board includes a metal pattern layer including a conductive pattern layer including the pattern fuse and a film layer attached to one surface of the metal pattern layer,
the flexible printed circuit board;
an injection molding product disposed to be spaced apart from the flexible printed circuit board; and
an air layer forming structure disposed between the flexible printed circuit board and the injection-molded product and fixing the flexible printed circuit board to the injection-molded product;
including,
An installation structure of a flexible printed circuit board, characterized in that an air layer is formed between the flexible printed circuit board and the air layer forming structure.
According to claim 1,
The air layer forming structure is an installation structure of a flexible printed circuit board, characterized in that any one of an epoxy resin, a foam foamed with a resin, and an adhesive tape.
3. The method of claim 1 or 2,
An installation structure of a flexible printed circuit board, characterized in that grooves are formed in the surface facing the film layer of the injection-molded product.
3. The method of claim 1 or 2,
The installation structure of the flexible printed circuit board, characterized in that the ribs protrude from the surface of the injection-molded product toward the film layer and extend along the surface of the injection-molded product.
5. The method of claim 4,
The rib is an installation structure of a flexible printed circuit board, characterized in that extended in a closed figure shape.
6. The method of claim 5,
The rib is an installation structure of a flexible printed circuit board, characterized in that the protrusion is formed to form a concave curved surface along the inner edge of the figure shape.
5. The method of claim 4,
The rib is an installation structure of a flexible printed circuit board, characterized in that the one side is formed at a position in contact with the one side of the air layer forming structure.

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