JP7165374B1 - Electronic device and its manufacturing method - Google Patents

Abstract

Provided are an electronic device capable of absorbing dimensional variations in an external connection portion provided on a circuit board and absorbing vibration of the circuit board, and a method of manufacturing the same. A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a substrate that is made of a synthetic resin material and that is deformable in the thickness direction and has substantially no elasticity, and the other side that is opposite to the one surface of the substrate A hard resin layer covering the base material and a soft resin layer having lower rigidity than the hard resin layer and covering the base material without an adhesive layer are integrally molded.

Description

The present invention relates to an electronic device and its manufacturing method.

a semiconductor substrate having an integrated circuit and an electrode electrically connected to the integrated circuit; a passivation film located on the semiconductor substrate while avoiding at least a portion of the electrode; a resin layer located on a portion of the passivation film; a wiring electrically connected to the electrode on the electrode and extending from the electrode onto the resin layer, the resin layer including a hard portion and a soft portion softer than the hard portion, and overlapping the wiring of the resin layer. A semiconductor device is known in which the volume ratio of the soft portion at the end opposite to the electrode is larger than the volume ratio of the soft portion at the end closer to the electrode (Patent Document 1).

A mounting board having a wiring pattern provided on its surface, a base electrically connected to each wiring pattern, and a terminal extending from the base, wherein the terminals are arranged to face each other. a pair of terminal members, a ceramic capacitor having electrodes electrically connected to the terminal portions and sandwiched between the pair of terminal members so as to be positioned at a predetermined height from the surface of the mounting substrate, and the terminal portions of the terminal members. A gel-like or rubber-like soft resin part that seals at least the connecting part from the base to the lower end of the ceramic capacitor, and the ceramic capacitor and the terminal member are collectively sealed together with other electronic components mounted on the mounting substrate. A power supply device including a hard resin portion that is harder than the soft resin portion is also known (Patent Document 2).

JP 2008-153367 A JP 2014-123606 A

SUMMARY OF THE INVENTION The present invention provides an electronic device and a method of manufacturing the same that can absorb dimensional variations in external connection portions provided on a circuit board and vibration of the circuit board.

In order to solve the above problems, the electronic device according to claim 1 comprises:
A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a base material made of a thermoplastic resin and deformable in the thickness direction;
A hard resin layer that covers the base material, and a region of the base material that has lower rigidity than the hard resin layer and is close to the external connection terminals mounted on the circuit board, on the other surface opposite to the one surface of the base material. and a resin layer integrally formed with a soft resin layer that covers the base material without an adhesive layer,
It is characterized by

In order to solve the above problems, the electronic device according to claim 2 includes:
A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a base material made of a thermoplastic resin and deformable in the thickness direction;
a hard resin layer covering the base material, and a region of the base material having lower rigidity than the hard resin layer and close to a fixing portion to which the electronic device is fixed to the outside, on the other surface opposite to the one surface of the base material; and a resin layer integrally formed with a soft resin layer that covers the base material without an adhesive layer,
It is characterized by

In order to solve the above problems, the electronic device according to claim 3 includes:
A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a base material made of a thermoplastic resin and deformable in the thickness direction;
a hard resin layer covering the base material on the other surface opposite to the one surface of the base material; and a resin layer integrally formed with a soft resin layer that covers the base material without an adhesive layer,
It is characterized by

The invention according to claim 4 is the electronic device according to any one of claims 1 to 3,
The conductive pattern formed in the region where the other surface of the base material is covered with the soft resin layer is thicker than the conductive pattern formed in the region covered with the hard resin layer. It is formed in a meander shape so that the elongation rate becomes small when deformed in the direction,
It is characterized by

The invention according to claim 5 is the electronic device according to any one of claims 1 to 4 ,
The substrate in the region where the other surface is covered with the soft resin layer has a larger elongation rate than the substrate in the region covered with the resin layer when the substrate is deformed in the thickness direction. A notch is formed in the thickness direction in the
It is characterized by

According to the invention of claim 6 , in the electronic device of any one of claims 1 to 5 ,
At least one resin selected from the group consisting of acrylonitrile-butadiene-styrene (ABS) resin, polycarbonate (PC) resin, polybutylene terephthalate (PBT) resin, and polycarbonate acrylonitrile-butadiene-styrene (PC/ABS) resin for the hard resin layer. When the material is included, the soft resin layer is combined with thermoplastic polyurethane elastomer (TPU) or thermoplastic polyester elastomer (TPC),
When the hard resin layer contains a resin material made of polypropylene (PP) resin or polyethylene (PE) resin, the soft resin layer is combined with an olefinic thermoplastic elastomer (TPO).
It is characterized by

In order to solve the above problems, the method for manufacturing an electronic device according to claim 7 includes:
A rigid substrate made of a thermoplastic resin that is deformable in the thickness direction and on which a conductive pattern made of a metal plating layer is arranged on one surface of the substrate, the substrate being covered on the other surface opposite to the one surface of the substrate. A method for manufacturing an electronic device in which a resin layer and a soft resin layer having lower rigidity than the hard resin layer and covering the base material without an adhesive layer are integrally formed,
preparing the substrate;
disposing the conductive pattern on the one surface of the substrate by electrolytic plating or electroless plating;
a step of forming a cut in a thickness direction of the base material in a region where the soft resin layer is formed of the base material on which the conductive pattern is arranged;
a step of applying an adhesive to the other surface of the base material except for a region where the soft resin layer is to be formed;
A step of placing the substrate coated with the adhesive in a mold and sequentially injection-molding a hard resin layer and a soft resin layer covering at least one surface of the substrate to integrate them;
It is characterized by

According to the first aspect of the invention, it is possible to absorb the dimensional variation of the external connection portion provided on the circuit board and to absorb the vibration of the circuit board.

According to the second aspect of the invention, vibration applied to the electronic device can be absorbed.

According to the third aspect of the invention, it is possible to absorb the dimensional variation of the connecting portion formed in the electronic device.

According to the fourth aspect of the invention, disconnection due to bending deformation of the conductive pattern can be suppressed.

According to the fifth aspect of the invention, when the base material is bent and deformed, the cut is opened and extended, and the extension of the area where the conductive pattern is arranged is reduced.

According to the sixth aspect of the invention, it is possible to improve the adhesion between the hard resin layer and the soft resin layer.

According to the seventh aspect of the invention, it is possible to absorb the dimensional variation of the external connection portion provided on the circuit board and to absorb the vibration of the circuit board.

FIG. 1A is a schematic plan view showing an example of an electronic device according to this embodiment, and FIG. 1B is a schematic cross-sectional view showing an example of the electronic device. FIG. 2A is a schematic plan view explaining the relationship between the cut formed in the base material and the conductive pattern, and FIG. 2B shows the elongation and cut of the conductive pattern when the base material on which the cut is formed is deformed in the thickness direction. It is a figure explaining the opening of. FIG. 3A is a schematic plan view showing an example of an electronic device in which a soft resin layer is formed so as to cover the other surface of the substrate in a region near the fixing portion, and FIG. 3B is a schematic cross-sectional view. FIG. 4A is a schematic plan view showing an example of an electronic device in which a soft resin layer is formed so as to cover the other surface of a substrate in a region surrounding electronic components mounted on a circuit board, and FIG. 4B is a schematic cross-sectional view. . It is a flowchart figure which shows an example of the procedure of the outline of the manufacturing method of an electronic device. It is a partial cross-sectional schematic diagram of the electronic device for demonstrating the manufacturing process of an electronic device. FIG. 3 is a schematic cross-sectional view showing an electronic device that has undergone deformation in the thickness direction of a base material in a flexible region;

Next, specific examples of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.
It should be noted that in the following description using the drawings, the drawings are schematic, and the ratio of each dimension is different from the actual one. Illustrations other than members are omitted as appropriate.

(1) Overall Configuration of Electronic Device FIG. 1A is a schematic plan view showing an example of the electronic device 1 according to the present embodiment, FIG. 1B is a schematic cross-sectional view showing an example of the electronic device 1, and FIG. FIG. 2B is a schematic plan view for explaining the relationship between the cut S and the conductive pattern 3, and FIG. 3A is a schematic plan view showing an example of the electronic device 1 in which the soft resin layer 5B is formed to cover the other surface 2b of the base material 2 in a region near the fixing portion 8, and FIG. 3B is a cross-sectional view FIG. 4A is a schematic plan view showing an example of the electronic device 1 in which the soft resin layer 5B is formed so as to cover the other surface 2b of the substrate 2 in the area surrounding the electronic component 3D mounted on the circuit board 4. , and FIG. 4B is a schematic cross-sectional view.
Hereinafter, the configuration of the electronic device 1 according to this embodiment will be described with reference to the drawings.

As shown in FIG. 1, the electronic device 1 includes a circuit board 4 having a conductive pattern 3 made of a metal plating layer disposed on one surface 2a of a substrate 2, and the other surface opposite to the one surface 2a of the substrate 2. In 2b, a resin layer 5 in which a hard resin layer 5A covering the base material 2 and a soft resin layer 5B having lower rigidity than the hard resin layer 5A and covering the base material 2 without an adhesive layer are integrally molded. configured with.

(Base material)
The base material 2 in the present embodiment is an insulating film-like base material that is made of a synthetic resin material and that is deformable in the thickness direction and has substantially no stretchability. Here, a "deformable substrate" is one that can be deformed after placement of the conductive pattern 3, i.e. from a substantially flat two-dimensional shape to a substantially three-dimensional shape by thermoforming, vacuum forming or air pressure forming. It means a substrate that can be deformed into a shape.
In addition, the expression that the base material 2 is “substantially non-stretchable” means that the base material 2 hardly stretches even if a pulling force is applied to the base material 2 in a certain direction. For example, for a sample of a predetermined size, if the sample is pulled in the longitudinal direction with a material tensile tester and the elongation at break when the sample breaks is 10% or less, the sample stretches in the longitudinal direction. have no gender.

The deformable and substantially non-stretchable base material 2 has a region R1 (indicated by a dashed line in FIG. 2A ) where the conductive pattern 3B of the region W that undergoes deformation in the thickness direction is arranged, and the conductive pattern 3B. The elongation rate of the base material 2 is different in the region R2 (indicated by a two-dot chain line in FIG. 2A) where is not arranged.
As will be described later, a meandering conductive pattern 3B is arranged in a region W where the substrate 2 is deformed in the thickness direction, and a cut S is formed in a region R2 between the meandering conductive patterns 3B. It is desirable to When the substrate 2 is deformed, the notch S is opened and stretched to reduce the stretch of the region R1 where the meander-shaped conductive pattern 3B is arranged, thereby preventing deformation (bending) of the conductive pattern 3B. Disconnection that accompanies this can be suppressed.

Examples of materials for the base material 2 include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides such as nylon 6-10 and nylon 46, polyetheretherketone (PEEK), ABS, PMMA, Thermoplastic resins such as polyvinyl chloride may be mentioned.
In particular, polyester is more preferable, and among these, polyethylene terephthalate (PET) is most preferable because it has a good balance of economy, electrical insulation, chemical resistance, and the like.

One surface 2a of the substrate 2 is preferably surface-treated in order to evenly apply catalyst ink such as metal nanoparticles. As the surface treatment, for example, corona treatment, plasma treatment, solvent treatment, and primer treatment can be used.

(Conductive pattern)
The conductive pattern 3 includes a linear conductive pattern 3A arranged in a region where the substrate 2 is not deformed in the thickness direction, and a meandering conductive pattern 3A arranged in a region where the substrate 2 is deformed in the thickness direction. It consists of sexual pattern 3B.

The meander-shaped conductive pattern 3B is formed so as to meander repeatedly in a direction intersecting with the extending direction of the linear conductive pattern 3A, and has a long wiring length. The meander-shaped conductive pattern 3B has a longer wiring length than a linear shape, so that when the base material 2 is deformed in the thickness direction, the conductive pattern 3B is easily stretched, and the conductive pattern 3B does not break. suppressed.

When the conductive pattern 3 is arranged on the one surface 2a of the base material 2, first, a base layer (not shown) made of a catalyst such as metal nanoparticles that triggers growth of the metal plating is formed in a predetermined pattern. Here, the predetermined pattern includes a meandering shape. The base layer is formed by applying a catalyst ink such as metal nanoparticles on the substrate 2, followed by drying and baking.

The thickness (μm) of the underlayer is preferably 0.1 to 20 μm, more preferably 0.2 to 5 μm, most preferably 0.5 to 2 μm. If the underlayer is too thin, the strength of the underlayer may decrease. Also, if the underlayer is too thick, the manufacturing cost may increase because metal nanoparticles are more expensive than ordinary metals.

Gold, silver, copper, palladium, nickel, and the like are used as the material of the catalyst. Gold, silver, and copper are preferable from the viewpoint of conductivity, and copper, which is cheaper than gold and silver, is most preferable.

The particle size (nm) of the catalyst is preferably 1 to 500 nm, more preferably 10 to 100 nm. If the particle size is too small, the reactivity of the particles increases, which may adversely affect the storability and stability of the ink. If the particle size is too large, it may become difficult to form a uniform thin film, and the particles of the ink may easily precipitate.

The conductive pattern 3 is formed on the underlying layer by electroplating or electroless plating. As the plating metal, copper, nickel, tin, silver, gold, or the like can be used, but copper is most preferable from the viewpoint of extensibility, conductivity and cost. In the present embodiment, the conductive pattern 3 is formed in a meandering shape and an oblique shape in the region W where the substrate 2 is shaped.

The thickness (μm) of the plating layer is preferably 0.03 to 100 μm, more preferably 1 to 35 μm, most preferably 3 to 18 μm. If the plated layer is too thin, the mechanical strength may be insufficient, and sufficient electrical conductivity may not be obtained for practical use. If the plating layer is too thick, the time required for plating will be long, and there is a risk that the manufacturing cost will increase.

(Electronic parts)
Although the conductive pattern 3 is arranged as a touch sensor 3C in FIG. 1, a plurality of electronic components 3D may be attached to the conductive pattern 3. FIG. Electronic components 3D include control circuits, strain, resistance, capacitance, touch sensing such as TIR, and light detection components, tactile or vibration components such as piezoelectric actuators or vibration motors, light emitting components such as LEDs, microphones and Producing or receiving sounds such as speakers, device operating components such as memory chips, programmable logic chips and CPUs, digital signal processors (DSP), ALS devices, PS devices, processing devices, MEMS, and the like.

A plurality of connector connection pads 3a may be formed at one end of the conductive pattern 3, and a connector 6, which is an external connection terminal for electrically connecting to an external element, may be electrically connected.
The connector 6 includes a terminal portion 61 electrically connected to the conductive pattern 3 and electrically connected to an external element provided outside, a housing 62 holding the terminal portion 61, and the housing 62. and a tail 63 for securing the housing 62 to the circuit board 4 .

(resin layer)
The resin layer 5 includes a hard resin layer 5A covering the other surface 2b of the base material 2 opposite to the one surface 2a on which the conductive pattern 3 is arranged, and the other surface of the base material 2 having lower rigidity than the hard resin layer 5A. A soft resin layer 5B that covers 2b without an adhesive layer is integrally molded.
The hard resin layer 5A is a thermoplastic resin made of an injection-moldable thermoplastic resin material. Specifically, from acrylic butadiene styrene (ABS) resin, polycarbonate (PC) resin, polybutylene terephthalate (PBT) resin, polycarbonate acrylonitrile butadiene styrene (PC/ABS) resin, polypropylene (PP) resin, polyethylene (PE) resin It contains at least one resin material selected from the group consisting of the adhesive layer AD, and is formed to cover the other surface 2b of the region of the substrate 2 that is not deformed in the thickness direction via the adhesive layer AD.

The soft resin layer 5B is a thermoplastic elastomer resin that can be injection molded, and is formed so as to cover the other surface 2b of the area (flexible area) that receives deformation in the thickness direction of the base material 2 without the adhesive layer AD. there is As shown in FIG. 1, the area that undergoes deformation in the thickness direction of the base material 2 is close to the connector 6 mounted on the circuit board 4, and stress is generated in the circuit board 4 when there is mounting variation in the connector 6. 3, the area where the circuit board 4 is likely to be distorted when vibration is applied from the outside near the fixing portion 8 where the electronic device 1 is fixed to the outside, as shown in FIG. Examples include a region near a connection portion (not shown) connected to the outside, where stress is likely to occur in the circuit board 4 when there is connection variation.

In the electronic device 1, the electronic component 3D is fixed by soldering one end of a metal wiring (not shown) to the conductive pattern 3 arranged on the one surface 2a of the base material 2, or is made of a conductive wire according to the mounting mode. are electrically and mechanically joined. As shown in FIG. 4, the soft resin layer 5B may be formed so as to surround the other surface 2b of the substrate 2 in a region surrounding the mounted electronic component 3D. Alternatively, the area surrounding the connector 6 may be formed so as to surround the other surface 2b of the base material 2 .

As the resin material of the soft resin layer 5B, specifically, the hard resin layer 5A is made of acrylic butadiene styrene (ABS) resin, polycarbonate (PC) resin, polybutylene terephthalate (PBT) resin, polycarbonate acrylonitrile butadiene styrene (PC/ABS ) When containing at least one resin material selected from the group consisting of resins, the soft resin layer 5B is combined with a thermoplastic polyurethane elastomer (TPU) or a thermoplastic polyester elastomer (TPC) and integrated with the hard resin layer 5A. molded.

Further, when the hard resin layer 5A contains a polypropylene (PP) resin or a polyethylene (PE) resin, the soft resin layer 5B is combined with an olefinic thermoplastic elastomer (TPO). An olefinic thermoplastic elastomer is a soft resin containing a polyolefinic resin and a rubber component. The rubber component may be dispersed in the polyolefinic resin, or they may be copolymerized with each other.
Specific examples of olefinic thermoplastic elastomers include ethylene-propylene copolymer elastomers.

Regarding the strength of thermoplastic polyurethane elastomer (TPU), thermoplastic polyester elastomer (TPC), olefinic thermoplastic elastomer (TPO), etc., the tensile modulus is preferably in the range of 50 to 200 MPa. If the tensile modulus is within the range of 50 to 200 MPa, it is possible to impart appropriate flexibility to the soft resin layer 5B, preferably within the range of 50 to 100 MPa, more preferably within the range of 50 to 70 MPa. be.

The soft resin layer 5B covers the flexible region of the circuit board 4 without the adhesive layer AD interposed therebetween, so that relative movement between the soft resin layer 5B and the base material 2 is not restricted, and bending is facilitated. there is Thereby, when an external force acts on the circuit board 4, the external force can be absorbed by the flexible region.

(2) Manufacturing method of electronic device FIG. 5 is a flow chart showing an example of a schematic procedure of a manufacturing method of the electronic device 1, and FIG. is.

The electronic device 1 includes, as shown in FIG. a cut forming step S13 for forming a cut S in a region R2 between the conductive patterns 3B; It is manufactured through a resin filling step S14 of injection molding a resin layer 5 covering the other surface 2b on the opposite side, and a mounting step S15 of mounting an electronic component 3D including a connector 6 on the one surface 2a of the base material 2.

(Base material preparation step S11)
In the base material preparation step S11, metal plating is first performed on the base material 2 in order to dispose the conductive pattern 3 on the substantially flat film-like base material 2 formed in a predetermined shape and size. A base layer made of catalyst particles such as metal nanoparticles that trigger growth is formed in a predetermined pattern including a meandering shape. In order to uniformly apply catalyst ink composed of catalyst particles such as metal nanoparticles, the substrate 2 is preferably subjected to surface treatment such as corona treatment, plasma treatment, solvent treatment, and primer treatment.

Methods for applying a catalyst ink made of catalyst particles such as metal nanoparticles on the substrate 2 include an inkjet printing method, a silk screen printing method, a gravure printing method, an offset printing method, a flexographic printing method, a roller coater method, and a brush coating method. Methods include spray method, knife jet coater method, pad printing method, gravure offset printing method, die coater method, bar coater method, spin coater method, comma coater method, impregnation coater method, dispenser method, and metal mask method. In this embodiment, an inkjet printing method is used.

Specifically, after applying a low-viscosity catalyst ink of 1000 cps or less, for example, 2 cps to 30 cps, by an inkjet printing method, the solvent is volatilized to leave only the metal nanoparticles. The solvent is then removed (drying) and the metal nanoparticles are sintered (firing).
The firing temperature is preferably 100°C to 300°C, more preferably 150°C to 200°C. If the sintering temperature is too low, the sintering of the metal nanoparticles will be insufficient, and components other than the metal nanoparticles will remain, which may result in poor adhesion. Also, if the firing temperature is too high, the base material 2 may be deteriorated or distorted.

(Wiring plating step S12)
Electroplating or electroless plating is applied to the base layer formed on the base material 2 to deposit plating metal on the surface and inside of the base layer, thereby arranging the conductive patterns 3A and 3B (see FIG. 6A). . The plating method is the same as a known plating solution and plating treatment, specifically electroless copper plating and electrolytic copper plating.

(Incision forming step S13)
A meandering conductive pattern 3B is formed in a region W where the substrate 2 is deformed in the thickness direction, and a cut S is formed in a region R2 between the meandering conductive patterns 3B (see FIG. 6B). ).

The incision S is formed with a depth that penetrates depending on the thickness of the base material 2, for example, if the thickness of the base material 2 is thin, using a laser device that irradiates a laser beam, die cutting, or a cutter blade. do. If the base material 2 is thick, it may be formed to a depth that does not penetrate.

(Resin filling step S14)
In the resin filling step S14, first, the substrate 2 and the hard resin layer 5A are formed in the area where the hard resin layer 5A is formed on the other surface 2b opposite to the one surface 2a of the substrate 2 on which the conductive pattern 3 is arranged. A binder ink for forming an adhesive layer AD is applied according to the combination of resin materials (see FIG. 6C). The binder ink contains an adhesive resin, is applied by screen printing, inkjet printing, spray coating, brush coating, or the like, and improves the adhesiveness between the base material 2 and the injection-molded hard resin layer 5A.

Next, the substrate 2 is positioned and set in the injection mold K. As shown in FIG. When the base material 2 is set in the cavity CA of the injection mold K, a double-sided tape is attached to the surface of the cavity CA so that the base material 2 is self-adsorbed to the surface of the cavity CA so as not to be displaced. It may be fixed by affixing with , vacuum suction, or by providing a projection (not shown) in the cavity CA and fitting it into the projection.

Then, in a state in which the substrate 2 is positioned and set in the injection molding die K, the die is closed and the cavity CA is filled with resin.
The filling of the resin is preferably carried out by a two-color molding method in which the hard resin layer 5A and the soft resin layer 5B are sequentially filled.

Specifically, as the cavity CA (only the cavity for forming the resin layer 5 is shown), a first cavity CA1 for forming the hard resin layer 5A and a second cavity CA2 for forming the soft resin layer 5B are prepared. In the state where the first cavity CA1 is formed in the injection mold K (see FIG. 6C), the molten resin for forming the hard resin layer 5A is filled from the first nozzle (not shown) of the injection molding machine to form the hard resin layer. Mold layer 5A.
Next, the mold for injection molding K is opened and the mold is rotated to form a second cavity CA2 in the mold for injection molding K (see FIG. 6D). A molten resin for forming the resin layer 5B is filled to mold the soft resin layer 5B.
At this time, the later molded soft resin layer 5B is heat-sealed and integrated with the previously molded hard resin layer 5A in the contact area. The order of filling the hard resin layer 5A and the soft resin layer 5B may be either first.

Here, as the resin forming the hard resin layer 5A, any one of acrylic butadiene styrene (ABS) resin, polycarbonate (PC) resin, polybutylene terephthalate (PBT) resin, and polycarbonate acrylonitrile butadiene styrene (PC/ABS) resin is used. In this case, by using a thermoplastic polyurethane elastomer (TPU) or a thermoplastic polyester elastomer (TPC) as the resin forming the soft resin layer 5B, the adhesion between the hard resin layer 5A and the soft resin layer 5B is improved.
Similarly, when either polypropylene (PP) resin or polyethylene (PE) resin is used as the resin forming the hard resin layer 5A, the resin forming the soft resin layer 5B is olefinic thermoplastic elastomer (TPO). By using it, the adhesion between the hard resin layer 5A and the soft resin layer 5B is improved.

(Mounting step S15)
In the mounting step S15, the electronic component 3D and the connector 6 are electrically joined to the conductive pattern 3 of the circuit board 4 for surface mounting.
The electronic component 3D is fixed by soldering one end (not shown) of the metal wiring, or is electrically and mechanically joined by a wire bonding method using ultrasonic waves with a conductive wire according to the mounting mode.
The connector 6 is fixed by soldering to a connector connection pad 3 a having a terminal portion 61 formed at one end of the conductive pattern 3 . In particular, since the soft resin layer 5B is formed on the other surface 2b of the base material 2 where the connector 6 is mounted, the electronic device 1 can be deformed in the thickness direction of the base material 2, and the mounting variation of the connector 6 is reduced. is easily absorbed.

(3) Action of Electronic Device FIG. 7 is a schematic cross-sectional view showing the electronic device 1 subjected to deformation in the thickness direction of the base material 2 in the flexible region.
The electronic device 1 includes a circuit board 4 on which a conductive pattern 3B having a partially meandering shape is arranged on one surface 2a of a base material 2, and an electronic component 3D and a connector 6 which are surface-mounted on the one surface 2a of the base material 2. , a hard resin layer 5A covering the base material 2 and a soft resin layer 5A having lower rigidity than the hard resin layer 5A and covering the base material 2 without an adhesive layer AD interposed therebetween. It has a resin layer 5 integrally formed with the resin layer 5B.
The soft resin layer 5B is formed so as to cover the other surface 2b of the area (flexible area) where the substrate 2 is deformed in the thickness direction.

According to such an electronic device 1, the electronic device 1 can be deformed in the thickness direction of the base material 2 with the soft resin layer 5B as a starting point, as schematically indicated by an arrow in FIG. For this reason, as shown in FIG. 1, by forming the soft resin layer 5B in a region near the connector 6 mounted on the circuit board 4, the electronic device 1 can be connected to the external element when the connector 6 is attached unevenly. At the time of connection, the terminal portion 61 of the connector 6 and the solder fixing portion of the connector connection pad 3a can be deformed so as to relieve the stress generated.

The electronic component 3D is fixed by soldering one end of the metal wiring (not shown) to the conductive pattern 3 arranged on the one surface 2a of the base material 2, or is electrically and mechanically connected by a conductive wire according to the mounting mode. are joined together. As shown in FIG. 4, the soft resin layer 5B is formed so as to surround the other surface 2b of the base material 2 in a region surrounding the mounted electronic component 3D, thereby absorbing vibration applied to the electronic component 3D. , and can be deformed so as to relax the stress generated at the junction between the electronic component 3D and the conductive pattern 3. As shown in FIG.

Further, as shown in FIG. 3, by forming the soft resin layer 5B in a region close to the fixing portion 8 to which the electronic device 1 is fixed to the outside, vibration is generated in the circuit board 4 when vibration is applied from the outside. It becomes deformable to absorb strain. Alternatively, when there is connection variation in the vicinity of a connection portion (not shown) where the electronic device 1 is connected to the outside, the circuit board 4 can be deformed so as to relieve the stress acting on it.

In this way, in the flexible region of the deformable electronic device 1, the conductive patterns 3 are arranged in a meandering shape, and the substrate 2 is cut S in the region R2 between the conductive patterns 3B bent in the meandering shape. is formed. Accordingly, when the electronic device 1 is deformed, as shown in FIG. 2B, the conductive pattern 3B is easily stretched, and the base material 2 is stretched by opening the cut S, so that the meander-shaped conductive pattern 3B is arranged. By reducing the elongation of the region R1, disconnection due to deformation (bending) of the conductive pattern 3B is suppressed.

As described above, according to the electronic device 1 according to the present embodiment, it is possible to absorb the dimensional variation of the external connection portion provided on the circuit board 4 and to absorb the vibration of the circuit board 4 .

DESCRIPTION OF SYMBOLS 1... Electronic device 2... Base material, 2a... One side (conductive pattern 3 side), 2b... Other side (resin layer 5 side)
3 conductive pattern 3A linear conductive pattern 3B meander conductive pattern 3C touch sensor 3D electronic component 4 circuit board 5. Resin layer 5A Hard resin layer 5B Soft resin layer 6 Connector 61 Terminal portion S Notch AD Adhesive layer K For injection molding Mold CA: Cavity, CA1: First cavity, CA2: Second cavity

Claims (7)

A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a base material made of a thermoplastic resin and deformable in the thickness direction;
A hard resin layer that covers the base material, and a region of the base material that has lower rigidity than the hard resin layer and is close to the external connection terminals mounted on the circuit board, on the other surface opposite to the one surface of the base material. and a resin layer integrally formed with a soft resin layer that covers the base material without an adhesive layer,
An electronic device characterized by: A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a base material made of a thermoplastic resin and deformable in the thickness direction;
a hard resin layer covering the base material, and a region of the base material having lower rigidity than the hard resin layer and close to a fixing portion to which the electronic device is fixed to the outside, on the other surface opposite to the one surface of the base material; and a resin layer integrally formed with a soft resin layer that covers the base material without an adhesive layer,
An electronic device characterized by: A circuit board in which a conductive pattern made of a metal plating layer is arranged on one surface of a base material made of a thermoplastic resin and deformable in the thickness direction;
a hard resin layer covering the base material on the other surface opposite to the one surface of the base material; and a resin layer integrally formed with a soft resin layer that covers the base material without an adhesive layer,
An electronic device characterized by: The conductive pattern formed in the region where the other surface of the base material is covered with the soft resin layer is thicker than the conductive pattern formed in the region covered with the hard resin layer. It is formed in a meander shape so that the elongation rate becomes small when deformed in the direction,
The electronic device according to any one of claims 1 to 3, characterized in that: The substrate in the region where the other surface is covered with the soft resin layer has a larger elongation rate than the substrate in the region covered with the resin layer when the substrate is deformed in the thickness direction. A notch is formed in the thickness direction in the
The electronic device according to any one of claims 1 to 4, characterized in that: At least one resin selected from the group consisting of acrylonitrile-butadiene-styrene (ABS) resin, polycarbonate (PC) resin, polybutylene terephthalate (PBT) resin, and polycarbonate acrylonitrile-butadiene-styrene (PC/ABS) resin for the hard resin layer. When the material is included, the soft resin layer is combined with thermoplastic polyurethane elastomer (TPU) or thermoplastic polyester elastomer (TPC),
When the hard resin layer contains a resin material made of polypropylene (PP) resin or polyethylene (PE) resin, the soft resin layer is combined with an olefinic thermoplastic elastomer (TPO).
The electronic device according to any one of claims 1 to 5, characterized in that: A rigid substrate made of a thermoplastic resin that is deformable in the thickness direction and on which a conductive pattern made of a metal plating layer is arranged on one surface of the substrate, the substrate being covered on the other surface opposite to the one surface of the substrate. A method for manufacturing an electronic device in which a resin layer and a soft resin layer having lower rigidity than the hard resin layer and covering the base material without an adhesive layer are integrally formed,
preparing the substrate;
disposing the conductive pattern on the one surface of the substrate by electrolytic plating or electroless plating;
a step of forming a cut in a thickness direction of the base material in a region where the soft resin layer is formed of the base material on which the conductive pattern is arranged;
a step of applying an adhesive to the other surface of the base material except for a region where the soft resin layer is to be formed;
A step of placing the substrate coated with the adhesive in a mold and sequentially injection-molding a hard resin layer and a soft resin layer covering at least one surface of the substrate to integrate them;
A method of manufacturing an electronic device, characterized by:

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