阅读说明：本技术 具有柔性印刷布线板的加热器及其制造方法 (Heater having flexible printed wiring board and method of manufacturing the same ) 是由 宫本雅郎 青山隼辅 于 2021-01-22 设计创作，主要内容包括：本发明提供具有柔性印刷布线板的加热器及其制造方法。所述加热器由柔性印刷布线板构成,所述柔性印刷布线板由基膜、第一金属箔和第二金属箔构成,所述第一金属箔将通过通电发热的加热器电路部形成在所述基膜的第一面上,并且,所述第二金属箔将保持非通电状态的热传导箔部形成在所述基膜的第二面上。(The invention provides a heater with a flexible printed wiring board and a manufacturing method thereof. The heater is constituted by a flexible printed wiring board constituted by a base film, a first metal foil that forms a heater circuit portion that generates heat by energization on a first surface of the base film, and a second metal foil that forms a heat conductive foil portion that remains in a non-energized state on a second surface of the base film.)

1. A heater is characterized in that a heater body is provided with a heating chamber,

is composed of a flexible printed wiring board,

the flexible printed wiring board is composed of a base film, a first metal foil, and a second metal foil,

the first metal foil forms a heater circuit portion that generates heat by energization on a first surface of the base film, and,

the second metal foil forms a heat conductive foil section that maintains a non-energized state on the second surface of the base film.

2. The heater of claim 1,

the heat conductive foil portion covers an area of the second face corresponding to an entire area of the first face where the heater circuit portion is provided, with the base film interposed therebetween.

3. The heater of claim 1 or 2,

the heater circuit portion is composed of a meandering heating wire having a certain line width,

the heater lines are arranged at equal intervals.

4. The heater of claim 1, 2 or 3,

the first metal foil further forms an energizing portion for energizing the heater circuit portion,

5. the heater of claim 4, comprising:

a first cover film covering the first metal foil;

a second cover film covering the second metal foil;

at least one electronic component disposed on a surface of the first cover film and electrically connected to the first metal foil; and

a connector electrically connected to the energizing part.

6. A method of manufacturing a heater having a flexible printed wiring board,

sequentially comprises an etching process and a laminating process,

the etching process includes:

etching a base film having a first metal foil on a first surface and a second metal foil on a second surface;

a heater circuit portion which generates heat by energization is formed by a part of the first metal foil; and

a part of the second metal foil is used to form a heat conduction foil part which is kept in a non-electrified state,

the lamination step includes:

a first cover film covering a surface of the first metal foil and a second cover film covering a surface of the second metal foil are provided.

7. The manufacturing method of a heater with a flexible printed wiring board according to claim 6,

the heat conductive foil portion covers an area of the second face corresponding to an entire area of the first face where the heater circuit portion is provided, with the base film interposed therebetween.

8. The manufacturing method of a heater with a flexible printed wiring board according to claim 6 or 7,

in the etching step, a part of the first metal foil forms a current-carrying portion for carrying current to the heater circuit portion.

9. The manufacturing method of a heater with a flexible printed wiring board according to claim 8,

further comprises a reflow step following the lamination step,

the reflow step includes:

at least one electronic component disposed on the surface of the first cover film and electrically connected to the first metal foil, and a connector electrically connected to the conducting portion are provided by reflow soldering.

Technical Field

The present invention relates to a heater having a flexible printed wiring board and a method of manufacturing the same.

Background

Conventionally, a film heater is used to heat a front windshield of an automobile. In recent years, Advanced Driving Assistance Systems (ADAS) are being developed. Further, in order to prevent fogging of the lens or the front windshield of the detection camera, the necessity of using a film-like heater is increased. A general film heater and a method for manufacturing the same will be described below with reference to fig. 7 and 8. Fig. 7 and 8 are process diagrams for manufacturing a general film heater.

First, the heater wire 510 is formed using a material that generates heat by energization (see fig. 7A). Examples of the material used for the heating wire 510 include nickel-chromium alloy, SUS, aluminum, platinum, iron, and nickel alloy, and pure metal. Next, a first insulating film 521 and a second insulating film 522 are provided on both surfaces of the heating wire 510, respectively. The first insulating film 521 and the second insulating film 522 sandwiching the heating wire 510 are bonded to each other by an adhesive layer 523 provided between these films (see fig. 7B). Then, a soaking plate 531 for uniformizing the heating temperature distribution is attached to the surface of the second insulating film 522 via the adhesive layer 532 (see fig. 7C). Fig. 7A is a plan view of the heater wire 510. Fig. 7B and 7C are schematic cross-sectional views of intermediate products in the process of manufacturing the heater.

Next, an electronic component 530 is mounted on the surface of the first insulating film 521 so as to be electrically connected to the heater wire 510 (see fig. 8A). The illustrated example shows an insulating film on which only one electronic component 530 is mounted. However, a plurality of electronic components may be mounted. In addition, a thermal fuse can be given as an example of the electronic element 530. Then, the wire harness 540 is electrically connected to the heater wire 510 by various methods such as crimping or welding (see fig. 8B). The connector 550 is electrically connected to an end of the wire harness 540 via a crimp pin (not shown). The connector 550 is connected to a device provided with a power supply for supplying power to the heater wire 510 or a control device for controlling temperature. The heater 500 is obtained through the above manufacturing process. Fig. 8A and B are plan views of an intermediate product in the process of manufacturing the heater. Fig. 8C is a top view of the finished heater 500.

The above manufacturing process for obtaining the heater 500 requires a process of attaching the soaking plate 531 and a process of attaching the wire harness 540. Therefore, many manufacturing processes are involved. Further, the adhesive layer 523, the second insulating film 522, and the adhesive layer 532 are interposed between the heater wire 510 and the soaking plate 531. Therefore, the thermal conductivity is low. Further, there is a fear that the adhesion of the soaking plate 531 to the second insulating film 522 is poor in reliability.

Disclosure of Invention

The invention aims to provide a heater with a flexible printed wiring board and a manufacturing method thereof, wherein the number of manufacturing processes can be reduced.

In the embodiment of the present invention, in order to solve the above problem, the following method is adopted.

That is, the heater of the present invention is constituted by a flexible printed wiring board constituted by a base film, a first metal foil which forms a heater circuit portion which generates heat by energization on a first surface of the base film, and a second metal foil which forms a heat conductive foil portion which is kept in a non-energized state on a second surface of the base film.

According to the present embodiment, the heat conductive foil portion is formed by the second metal foil. Therefore, a process of separately mounting a member for heat conduction such as a soaking plate is not required. In addition, only a base film is present between the heater circuit section and the heat conductive foil section. Therefore, the heat conductivity from the heater circuit portion to the heat conductive foil portion can be improved.

The heat conductive foil part may cover an area of the second face corresponding to an entire area of the first face where the heater circuit part is provided, with the base film interposed therebetween.

The heater circuit portion may be formed of a meandering heating wire having a predetermined line width, and the heating wire may be arranged at equal intervals.

In addition, the first metal foil may form a current-carrying portion for carrying current to the heater circuit portion.

Thus, a process of installing the wire harness is not required.

The heater further includes: a first cover film and a second cover film respectively covering the surface of the first metal foil and the surface of the second metal foil; at least one electronic component disposed on the front surface of the first cover film and electrically connectable to the first metal foil; and a connector provided in a state of being electrically connectable to the conducting portion.

The method for manufacturing a heater having a flexible printed wiring board according to the present invention includes an etching step and a laminating step in this order, the etching step including: etching a base film having a first metal foil on a first surface and a second metal foil on a second surface; a heater circuit portion which generates heat by energization is formed by a part of the first metal foil; and forming a heat conductive foil portion in a non-energized state by using a part of the second metal foil, the laminating step including: a first cover film covering a surface of the first metal foil and a second cover film covering a surface of the second metal foil are provided.

According to this embodiment, the heater circuit portion and the heat conductive foil portion are formed by an etching process. Therefore, the number of manufacturing processes can be reduced.

The heat conductive foil portion may cover an area of the second face corresponding to an entire area of the first face where the heater circuit portion is provided, with the base film interposed therebetween.

In the etching step, a part of the first metal foil may form a current-carrying portion for supplying current to the heater circuit portion.

Thus, the conductive portion is also formed by the etching step. Therefore, the number of manufacturing steps can be further reduced.

The method for manufacturing a heater having a flexible printed wiring board according to the present invention further includes a reflow step following the laminating step, and the reflow step may include a reflow step of providing at least one electronic component disposed on the surface of the first cover film and electrically connected to the first metal foil and a connector electrically connected to the conducting portion by reflow.

Thus, the electronic component and the connector can be mounted in the reflow step. Therefore, the number of manufacturing steps can be further reduced.

Further, the above-described respective configurations can be combined as much as possible.

As described above, according to the present embodiment, the number of manufacturing steps can be reduced.

Drawings

Fig. 1A and 1B are process diagrams for manufacturing a heater having a flexible printed wiring board according to an embodiment of the present invention.

Fig. 2A to 2C are process diagrams for manufacturing a heater having a flexible printed wiring board according to an embodiment of the present invention.

Fig. 3A to 3C are process diagrams for manufacturing a heater having a flexible printed wiring board according to an embodiment of the present invention.

Fig. 4A to 4C are process diagrams for manufacturing a heater having a flexible printed wiring board according to an embodiment of the present invention.

Fig. 5A to 5C are process diagrams for manufacturing a heater having a flexible printed wiring board according to an embodiment of the present invention.

Fig. 6A and 6B are plan views showing modifications of the heater circuit portion.

Fig. 7A to 7C are process diagrams for manufacturing a general film heater.

Fig. 8A to 8C are process diagrams for manufacturing a general film heater.

Detailed Description

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It may be evident, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

The present embodiment is described below in detail by way of example with reference to the accompanying drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangement, and the like of the components described in the embodiment do not limit the scope of the embodiment.

(embodiment mode)

The heater having a flexible printed wiring board and the method of manufacturing the heater according to the present embodiment will be described with reference to fig. 1A to 5C. Fig. 1A to 5C are process diagrams for manufacturing a heater having a flexible printed wiring board according to the present embodiment. The heater 10 of the present embodiment can be applied to heating a lens or a front windshield of a camera for detection. The heater 10 of the present embodiment can be applied not only to heating various components constituting an automobile but also to various devices other than an automobile. The heater 10 of the present embodiment has flexibility. Therefore, the heater 10 can be bent in various directions. Thus, the heater 10 can be used by being stuck along the curved surface even in a curved portion.

(Heater)

In particular, the structure of the heater having a flexible printed wiring board according to the present embodiment will be described with reference to fig. 5A to 5C. Fig. 5A to 5C show the product heater 10. Fig. 5A is a plan view of the heater 10. Fig. 5B is a schematic cross-sectional view of the heater 10 (corresponding to the EE cross-sectional view in fig. 5A). Fig. 5C is a bottom view of the heater 10.

The heater 10 of the present embodiment is roughly configured by a heating portion 250 for heating a heating target portion, an electric wiring portion 260, an electronic component 310 provided in the heating portion 250, and a connector 320 provided at an end portion of the electric wiring portion 260. The illustrated example shows only one electronic component 310. However, a plurality of electronic components may be provided depending on the application of the heater 10. Specific examples of the electronic element 310 include a thermistor for temperature control, a chip component such as a PTC element, and a temperature fuse. The connector 320 is provided to be connected to a device (not shown) including a power supply for energizing the heater circuit portion 121 or a control device for controlling the temperature.

Next, the internal configurations of the heating portion 250 and the electrical wiring portion 260 in the heater 10 will be described. The heater 10 of the present embodiment includes a base film 110, a heater circuit portion 121 and energizing portions 122 and 123 (see fig. 2A to 2C) provided on a first surface of the base film 110, and a soaking plate portion 131 as a heat conductive foil portion provided on a second surface of the base film 110. The heater circuit portion 121 is energized from a device (not shown) connected to the connector 320 through energizing portions 122 and 123. This generates heat, thereby constituting the heater circuit portion 121. In addition, the soaking plate portion 131 maintains a non-energized state. The soaking plate portion 131 is provided so as to cover a region of the second surface corresponding to a region of the first surface where the heater circuit portion 121 is provided, with the base film 110 interposed therebetween. Thereby, the heater circuit portion 121 generates heat and heats the soaking plate portion 131 via the base film 110. The entire region where the soaking plate portion 131 is provided (corresponding to the region where the heater circuit portion 121 is provided) is uniformly heated. The heating unit 250 corresponds to a region where the heater circuit unit 121 and the soaking plate unit 131 are provided. The electrical wiring portion 260 corresponds to a region where the conductive portions 122 and 123 are provided.

The heater 10 further includes a first cover film 211 covering the surfaces of the heater circuit portion 121 and the current-carrying portions 122 and 123. The first cover film 211 is bonded to the base film 110 with the first adhesive layer 212 interposed between the heater circuit portion 121 and the current-carrying portions 122 and 123. The first cover film 211 is provided with openings 211a and 211b for exposing a part of the heater circuit portion 121 and a part of the current-carrying portions 122 and 123. Also, the electronic element 310 provided on the surface of the first cover film 211 is electrically connected to the heater circuit portion 121. The electronic component 310 is connected to the heater circuit portion 121 exposed through the opening 211 a. The connector 320 is also electrically connected to the current-carrying portions 122 and 123. The connector 320 is also connected to the current-carrying portions 122 and 123 exposed through the opening 211 b.

The heater 10 also includes a second cover film 221 covering the surface of the soaking plate portion 131. The second cover film 221 is attached to the base film 110 with the second adhesive layer 222 so as to sandwich the soaking plate portion 131.

(method of manufacturing Heater having Flexible printed Wiring Board)

A method for manufacturing a heater having a flexible printed wiring board will be described in the order of manufacturing steps.

[ raw materials ]

Fig. 1A and 1B show a raw material 100 used for manufacturing the heater 10 of the present embodiment. Fig. 1A is a plan view showing a part of a material 100. Fig. 1B is a schematic sectional view of the raw material 100 (AA sectional view in fig. 1A).

The stock material 100 is commercially available and is commonly referred to as a double-sided copper clad laminate. The raw material 100 is provided with a first metal foil 120 and a second metal foil 130 on both sides of a base film 110, respectively. The base film 110 is composed of a resin material having insulation and flexibility, for example, Polyimide (PI) or polyethylene naphthalate (pen). The first metal foil 120 and the second metal foil 130 are made of copper foil. The raw material 100 having such a constitution has flexibility. Therefore, the material 100 can be bent in various directions.

[ etching Process ]

A resist pattern (a portion to be a mask) for forming the heater circuit portion 121 and the current-carrying portions 122 and 123 and a resist pattern for forming the heat conductive foil portion (the soaking plate portion 131) are formed on both surfaces of the material 100 by a method such as photolithography. Then, etching is performed. Thereby, unnecessary copper foil is removed. Thus, the heater circuit portion 121, the current-carrying portions 122 and 123, and the soaking plate portion 131 are formed. That is, the heater circuit portion 121 and the current-carrying portions 122 and 123 are formed by a part of the first metal foil 120. The soaking plate portion 131 is formed by a part of the second metal foil 130. The heater circuit portion 121, the current-carrying portions 122 and 123, and the soaking plate portion 131 are formed substantially simultaneously by etching. Fig. 2A to 2C show the first intermediate product 100X after the etching step. Fig. 2A is a top view of first intermediate article 100X. Fig. 2B is a cross-sectional view of the first intermediate product 100X (cross-sectional view BB in fig. 2A). Fig. 2C is a bottom view of the first intermediate article 100X.

In the present embodiment, the heater wire in the heater circuit portion 121 is provided so that the line width thereof is constant. The heater circuit portion 121 is configured to provide at least 1 row of a region (meandering region 121X) in which the heating wire is meandering at equal intervals (see fig. 2A). In the present embodiment, 4 rows of the meandering regions 121X are provided. However, it is needless to say that the pattern of the heater circuit portion 121 is not limited to the illustrated example. The method for forming the resist pattern is not limited to the photolithography technique, and various known techniques can be used.

[ laminating Process ]

After the etching step, a first cover film 211 covering the surface of the first metal foil 120 (corresponding to the heater circuit portion 121 and the current-carrying portions 122 and 123) and a second cover film 221 covering the surface of the second metal foil 130 (corresponding to the soaking plate portion 131) are provided. The first cover film 211 is adhered to the base film 110 via the first adhesive layer 212 so as to sandwich the heater circuit portion 121 and the current-carrying portions 122 and 123. In addition, the second cover film 221 is attached to the base film 110 with the second adhesive layer 222 so as to sandwich the soaking plate portion 131. The first cover film 211 and the second cover film 221 are also made of an insulating and flexible resin material, as in the case of the base film 110. The first cover film 211 is provided with the openings 211a and 211b as described above.

Fig. 3A to 3C show the second intermediate product 200 after the laminating step. Fig. 3A is a top view of second intermediate article 200, fig. 3B is a cross-sectional view (cross-sectional view CC in fig. 3A) of second intermediate article 200, and fig. 3C is a bottom view of second intermediate article 200. Various known techniques can be employed as a lamination method for providing the first cover film 211 and the second cover film 221. Therefore, the description thereof is omitted. Further, the second intermediate product 200 corresponds to a flexible printed wiring board.

(reflow soldering Process (mounting Process))

After the laminating step, the electronic component 310 and the connector 320 are mounted on the flexible printed wiring board, which is the second intermediate product 200. First, the exposed portions of the first metal foil 120 (corresponding to the heater circuit portion 121 and the current-carrying portions 122 and 123) are subjected to surface treatment such as gold plating or water-soluble preflux treatment through the openings 211a and 211 b. Then, soldering is performed in a reflow furnace. Thereby, various components are mounted. That is, in the present embodiment, the electronic component 310 is connected to the heater circuit portion 121 via the opening 211a by reflow soldering. The connector 320 is connected to the current-carrying portions 122 and 123 through the opening 211 b. Therefore, the mounting of the electronic component 310 and the mounting of the connector 320 can be performed substantially simultaneously in one process. Fig. 4A is a top view of the intermediate article. Fig. 4B is a sectional view of the intermediate product (DD sectional view in fig. 4A). Fig. 4C is a bottom view of the intermediate article.

[ cutting Process ]

After the reflow process, the intermediate product is cut so that the outer shape of the heater 10 is obtained from the second intermediate product 200. Thereby, the product heater 10 shown in fig. 5A to 5C is obtained. Further, a plurality of heaters 10 can be manufactured from one raw material 100.

(advantages of the Heater having a Flexible printed Wiring Board and the method of manufacturing the same according to the embodiment)

According to the heater 10 with a flexible printed wiring board and the manufacturing method thereof of the present embodiment, the soaking plate portion 131 as the heat conductive foil portion can be formed by the second metal foil 130. Therefore, a process of separately mounting a member for heat conduction such as a soaking plate is not required. That is, the heater circuit portion 121 and the soaking plate portion 131 can be formed substantially simultaneously by the etching step. As a result, the number of manufacturing steps can be reduced. In addition, only the base film 110 is provided between the heater circuit section 121 and the soaking plate section 131. Therefore, the heat conductivity from the heater circuit portion 121 to the soaking plate portion 131 can be improved. Also, the soaking plate portion 131 is formed of the second metal foil 130 that is a member of the raw material 100 that is previously adhered to the base film 110. Therefore, the possibility that the soaking plate portion 131 is peeled off from the base film 110 is also reduced.

The current-carrying portions 122 and 123 for supplying current to the heater circuit portion 121 are formed by the first metal foil 120. That is, the heater circuit portion 121 and the current-carrying portions 122 and 123 are formed substantially simultaneously by the etching step. Therefore, a conventional process for attaching a wire harness is not required. This reduces the number of parts and the number of manufacturing steps.

In the present embodiment, the electronic component 310 and the connector 320 can be mounted in the reflow step. Therefore, the number of manufacturing steps can be further reduced. In the heater 10 of the present embodiment, the flexible printed wiring board is not provided with a through hole. This eliminates the need for a process for providing the through-hole. In addition, in general, when the through hole plating is formed, variations in the film thickness of the conductor portion are likely to occur. As a result, the uniformity of the temperature distribution may be affected. However, in the present embodiment, such a possibility does not occur because no through hole is provided.

(others)

The pattern of the heater circuit portion 121 is not limited to the example shown in fig. 2A. Various patterns can be employed. An example thereof will be described with reference to fig. 6A to 6B. For convenience of explanation, fig. 6A to 6B show the first intermediate product (product after the etching step).

For example, as shown in fig. 6A, the following configuration can be adopted: a plurality of heat conductive foil portions 125 capable of maintaining a non-energized state are provided on the surface of the base film 110 on which the heater circuit portion 121 is provided. With such a configuration, the temperature distribution in the heating section 250 can be further uniformized. Even at the same amount of current, the heating temperature can be increased as compared with the pattern shown in fig. 2A.

As shown in fig. 6B, the meandering region 121X of the heater circuit portion 121 may be provided with a plurality of connecting portions 126 that short-circuit adjacent heater lines. Thus, the heater circuit portion 121 is provided with a portion that generates a high amount of heat by energization and a portion that generates a low amount of heat by energization, that is, the heat conductive foil portion 121Y that exhibits a low heat transfer function. Further, in the heat conductive foil portion 121Y, although a little current flows, heat is hardly generated by energization. The portion where the plurality of heat conductive foil portions 121Y are removed from the heater circuit portion 121 corresponds to the heat generating portion described above. With such a configuration, the heating temperature can be uniformly reduced in the vicinity where the plurality of heat conductive foil portions 121Y are provided, as compared with other regions. Therefore, when the heating temperature required in accordance with the use environment differs depending on the place, such a configuration can be preferably adopted.

In the above embodiment, the case where the heat conductive foil section is formed by the soaking plate section 131 in order to make the temperature of the entire heating section 250 uniform is exemplified. However, depending on the application of the heater, it may be desirable to uniformly raise the temperature of only a part of the heating portion and set the temperature to a lower temperature for the other part. Therefore, a structure in which the heat conductive foil portion is provided only in a part of the heating portion 250 (the region where the heater circuit portion 121 is provided) can also be employed. For example, a structure may be adopted in which the heat conductive foil portion is provided only in a half of the region where the heater circuit portion 121 is provided. Alternatively, the heat conductive foil portion may be provided along 4 sides of the rectangular region in which the heater circuit portion 121 is provided, and not provided in the center.

The detailed description has been presented for purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. The detailed description is not intended to be exhaustive or to limit the subject matter described herein. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts described are disclosed as example forms of implementing the claims.