JP7268962B2 - wiring circuit board - Google Patents

Description

The present invention relates to a wired circuit board.

2. Description of the Related Art Conventionally, electronic equipment is composed of elements having a plurality of printed circuit boards, which are electrically connected. For example, an electronic device includes a first wired circuit board that constitutes a main part thereof, and a second wired circuit board that constitutes a connection part and an accessory part. The terminals of the circuit board are electrically connected through solder (see Patent Document 1).

JP 2005-340385 A

By the way, in order to improve connection reliability, it is considered to increase the amount of solder. However, when a large amount of solder is placed on the terminals of the second printed circuit board, the solder may wet and spread around the terminals, or even spill out from the second printed circuit board. As a result, there arises a problem that the periphery of the terminal is contaminated with solder.

The present invention provides a printed circuit board that can improve connection reliability and suppress contamination to the surroundings.

The present invention [1] includes a connection portion having a planar shape extending in a plane direction, a curved portion continuous with the connection portion, and an extension portion continuous with the curved portion, wherein the connection portion includes a metal support layer. a wired circuit board, comprising: an insulating layer arranged on one side in the thickness direction of the metal supporting layer; and a pad section arranged on the one side in the thickness direction of the insulating layer and electrically connected to an electronic element. Prepare.

According to this wired circuit board, the connection portion, the curved portion, and the extension portion are provided, and the pad portion is arranged in the connection portion. Therefore, when a large amount of bonding material is placed on the pad portion, even if the bonding material wets and spreads, the bonding material is blocked by the curved portion. Therefore, the bonding material does not wet and spread to the extension part, and contamination of the periphery of the extension part by the bonding material can be suppressed.

Moreover, since a large amount of bonding material can be placed on the pad portion and connected to the terminal of the electronic element, connection reliability can be improved.

The present invention [2] includes the wired circuit board according to [1], wherein the planar view area of the pad portion is 50% or more of the planar view area of the connection portion.

According to this wired circuit board, the area of the pad portion is 50% or more of the connection portion. Therefore, the connection area between the electronic element and the pad portion can be increased, and the connection reliability can be further improved.

The present invention [3] includes the wired circuit board according to [1] or [2], wherein the pad section is arranged to straddle both the connection section and the curved section.

According to this wired circuit board, the pad portion extends over both the connection portion and the curved portion. Therefore, even the bonding material that has wetted and spread to the curved portion can come into contact with the pad portion, so that the bonding material can be effectively used. Therefore, connection reliability can be further improved.

According to the printed circuit board of the present invention, connection reliability can be improved and contamination to the surroundings can be suppressed.

FIG. 1 shows a perspective view (with an insulating cover layer omitted) of a first embodiment of the wired circuit board of the present invention. FIG. 2 shows a plan view of the printed circuit board shown in FIG. FIG. 3 shows a cross-sectional view of the wired circuit board shown in FIG. 1 taken along the line AA. 4A to 4D are process diagrams for bonding the wired circuit board shown in FIG. 1 to an electronic element, FIG. 4A being a process of preparing the electronic element, and FIG. 4B being a process of arranging the wired circuit board and the bonding material. 4C shows a step of inserting the connection portion of the printed circuit board into the opening, and FIG. 4D shows a step of bonding the external element and the body terminal pad. FIGS. 5A and 5B are modifications of process diagrams for bonding a conventional wired circuit board (in the form of a flat plate) to an electronic element, FIG. shows the step of inserting the connecting portion of the printed circuit board into the opening. FIGS. 6A and 6B are modifications of process diagrams for bonding a conventional wired circuit board (in the form of a flat plate) to an electronic device, FIG. shows the step of inserting the connecting portion of the printed circuit board into the opening. FIG. 7 shows a side sectional view of a second embodiment of the wired circuit board of the present invention.

In FIG. 2 , the horizontal direction on the page is the front-to-back direction (first direction), the right side on the page is the front side (one side in the first direction), and the left side on the page is the rear side (the other side in the first direction). The vertical direction of the paper is the left-right direction (the width direction, the second direction perpendicular to the first direction), the lower side of the paper is the left side (one side in the width direction, the one side in the second direction), and the upper side of the paper is the right side (width direction). direction other side, second direction other side). In addition, the paper thickness direction is the vertical direction (the thickness direction, the third direction orthogonal to the first direction and the second direction), and the front side of the paper is the upper side (one side in the thickness direction, one side in the third direction). The back side is the lower side (the other side in the thickness direction, the other side in the third direction). Specifically, it conforms to the directional arrows in each figure. Note that the insulating cover layer is omitted in FIG.

<First embodiment>
1. 1. Wired Circuit Board One embodiment of the wired circuit board of the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

A wired circuit board 1 shown in FIG.

As shown in FIGS. 1 and 3, the connection portion 2 has a planar shape, and more specifically, has a first surface extending in the direction of the first surface. The first plane is a plane along both the front-rear direction and the width direction, and the first plane direction is the direction along the first plane. Specifically, the first surface is the lower surface of the connection portion 2 (especially the lower surface of the support connection portion 61). As shown in FIG. 2, the connecting portion 2 has a flat plate shape that is approximately rectangular in plan view. The connecting portion 2 is arranged on the frontmost side of the printed circuit board 1 .

The connection portion 2 includes a metal support layer 6, an insulating base layer (an example of an insulating layer) 7, and a connection terminal pad portion (an example of a pad portion) 81, as shown in FIG. Specifically, the connection portion 2 includes a support connection portion 61 , a base connection portion 71 , and a tip portion of the connection terminal pad portion 81 .

The length (front-rear direction distance) L1 of the connecting portion 2 is, for example, 50 μm or more, preferably 100 μm or more, and is, for example, 2000 μm or less, preferably 1000 μm or less.

The planar view area of the connecting portion 2 is, for example, 1000 μm ² or more, preferably 5000 μm ² or more, more preferably 10000 μm ² or more, and is, for example, 10 mm ² or less, preferably 5 mm ^{2 or} less.

The curved portion 3 has a curved surface that curves from the first surface direction toward the second surface direction. Specifically, the curved surface is the lower surface of the curved portion 3 (in particular, the lower surface of the support curved portion 62). The curved portion 3 is arranged on the rear side of the connecting portion 2 so as to be continuous with the rear edge of the connecting portion 2 . Specifically, the curved portion 3 is arranged between the connecting portion 2 and the extending portion 4 so as to be continuous with the rear edge of the connecting portion 2 and the leading edge of the extending portion 4 .

The curved portion 3 has a substantially rectangular shape in plan view, as shown in FIG. Further, as shown in FIG. 3, the curved portion 3 has an arc shape that is convex downward in a side sectional view. The lateral distance (width) of the curved portion 3 is substantially the same as the lateral distance of the connection portion 2 .

The curvature radius R of the curved portion 3 is, for example, 50 μm or more, preferably 100 μm or more, and is, for example, 2000 μm or less, preferably 1000 μm or less.

The arc center C of the bending portion 3 is located above the bending portion 3, and the central angle θ thereof is, for example, 10° or more, preferably 20° or more, more preferably 30° or more, and For example, less than 90°, preferably 70° or less, more preferably 60° or less.

The length (longitudinal distance) L2 of the curved portion 3 is, for example, 50 μm or more, preferably 100 μm or more, and is, for example, 2000 μm or less, preferably 1000 μm or less.

The planar view area of the curved portion 3 is, for example, 1000 μm ² or more, preferably 5000 μm ² or more, more preferably 10000 μm ² or more, and is, for example, 10 mm ² or less, preferably 5 mm ^{2 or} less.

The length of the curved portion 3 or the plan view area is, as shown in FIGS. refers to area.

A ratio (L1/L2) of the length L1 of the connecting portion 2 to the length L2 of the bending portion 3 is, for example, 0.025 or more, preferably 0.1 or more, and, for example, 1.0 or less. , preferably 0.5 or less.

The bending portion 3 includes a metal support layer 6 , an insulating base layer 7 , a connection terminal pad portion 81 , a wiring portion 83 and an insulating cover layer 9 . Specifically, the curved portion 3 includes a support curved portion 62 , a base curved portion 72 , a rear portion of the connection terminal pad portion 81 , a front portion of the wiring portion 83 , and a front portion of the insulating cover layer 9 .

The extension 4 has a second surface extending in the direction of the second surface, as shown in FIGS. 1 and 3 . The second surface is a plane extending in both the front-rear direction and the width direction with an inclination, and the second surface direction is a direction along the second surface. The second surface is specifically the lower surface of the extension portion 4 (in particular, the lower surface of the support extension portion 63). The extension portion 4 is arranged on the rear side of the bending portion 3 so as to be continuous with the rear edge of the bending portion 3 . Specifically, the extension part 4 is arranged between the bending part 3 and the circuit main body part 5 so as to be continuous with the rear edge of the bending part 3 and the leading edge of the circuit main body part 5 . That is, the extension portion 4 is a connecting portion that connects the bending portion 3 and the circuit body portion 5 .

As shown in FIG. 2, the extension part 4 has a flat plate shape that is substantially rectangular in plan view. The lateral distance (width) of the extended portion 4 is substantially the same as the lateral distance of the curved portion 3 . The front-rear direction distance (length) of the extension portion 4 is longer than each of the length L1 of the connection portion 2 and the length L2 of the bending portion 3 .

The extension portion 4 includes a metal support layer 6, an insulating base layer 7, a wiring portion 83, and an insulating cover layer 9, as shown in FIG. Specifically, the extension portion 4 includes a support extension portion 63 , a base extension portion 73 , an intermediate portion of the wiring portion 83 , and an intermediate portion of the insulating cover layer 9 .

The circuit body portion 5 has a third surface extending in the direction of the second surface, as shown in FIGS. 1 and 3 . Specifically, the third surface is the lower surface of the circuit body portion 5 (in particular, the lower surface of the support body portion 64). The circuit body portion 5 is arranged on the rear side of the extension portion 4 so as to be continuous with the rear edge of the extension portion 4 . The circuit body portion 5 is arranged on the rearmost side of the wired circuit board 1 .

As shown in FIG. 2, the circuit main body 5 has a flat plate shape that is substantially rectangular in plan view. The horizontal distance (width) of the circuit body portion 5 is longer than the horizontal distance of the extension portion 4 .

The circuit body 5 includes a metal support layer 6, an insulating base layer 7, a body terminal pad portion 82, a wiring portion 83, and an insulating cover layer 9, as shown in FIG. Specifically, the circuit body portion 5 includes a support body portion 64 , a base body portion 74 , a body terminal pad portion 82 , a rear portion of the wiring portion 83 , and a rear portion of the insulating cover layer 9 .

Next, the layer structure of the printed circuit board 1 will be described. As shown in FIG. 3, the wired circuit board 1 includes a metal support layer 6, an insulating base layer 7, a conductor layer 8, and an insulating cover layer 9 in this order from the bottom.

The metal support layer 6 is arranged on the bottom layer of the printed circuit board 1 . The metal support layer 6 has the outer shape of the wired circuit board 1, and as shown in FIG. 2, has a substantially rectangular shape in plan view with a long protruding central portion in the left-right direction on the front side.

As shown in FIG. 3, the metal support layer 6 includes a support connection portion 61 corresponding to the connection portion 2, a support bending portion 62 corresponding to the bending portion 3, a support extension portion 63 corresponding to the extension portion 4, and a circuit. A support body portion 64 corresponding to the body portion 5 is integrally provided. The support connection portion 61, the support curved portion 62, the support extension portion 63, and the support body portion 64 are continuous in the front-rear direction.

The material of the metal support layer 6 can be appropriately selected from, for example, known or commonly used metal materials. Specifically, metal materials include metal elements classified into Groups 1 to 16 of the periodic table, and alloys containing two or more of these metal elements (for example, stainless steel). The metal material may be either a transition metal or a typical metal. More specifically, for example, Group 2 metal elements such as calcium, Group 4 metal elements such as titanium and zirconium, Group 5 metal elements such as vanadium, Group 6 metal elements such as chromium, molybdenum and tungsten, Group 7 metal elements such as manganese, Group 8 metal elements such as iron, Group 9 metal elements such as cobalt, Group 10 metal elements such as nickel and platinum, Group 11 metal elements such as copper, silver and gold , zinc and other group 12 metal elements, aluminum and gallium and other group 13 metal elements, and germanium and tin and other group 14 metal elements.

The thickness of the metal support layer 6 is, for example, 10 μm or more, preferably 30 μm or more, and for example, 150 μm or less, preferably 100 μm or less.

The insulating base layer 7 is arranged on the upper surface of the metal support layer 6 (surface on one side in the thickness direction). The outer shape of the insulating base layer 7 matches the outer shape of the metal support layer 6 when projected in the vertical direction.

The insulating base layer 7 includes a base connection portion 71 corresponding to the connection portion 2 , a base bending portion 72 corresponding to the bending portion 3 , a base extension portion 73 corresponding to the extension portion 4 , and a base corresponding to the circuit body portion 5 . A body portion 74 is integrally provided. The base connection portion 71, the base bending portion 72, the base extension portion 73, and the base body portion 74 are continuous in the front-rear direction.

The material of the base insulating layer 7 can be appropriately selected from, for example, known or commonly used insulating materials. Specifically, examples of insulating materials include synthetic resins such as polyimide resins, polyamideimide resins, acrylic resins, polyethernitrile resins, polyethersulfone resins, polyethylene terephthalate resins, polyethylene naphthalate resins, and polyvinyl chloride resins. is mentioned. Preferably, the insulating base layer 7 is made of polyimide resin.

The thickness of the insulating base layer 7 is, for example, 1 μm or more, preferably 3 μm or more, and is, for example, 30 μm or less, preferably 20 μm or less.

The conductor layer 8 is arranged on the upper surface of the insulating base layer 7 . The conductor layer 8 integrally includes a connection terminal pad portion 81 , a body terminal pad portion 82 , and a wiring portion 83 . The connection terminal pad portion 81, the wiring portion 83, and the body terminal pad portion 82 are continuous in the front-rear direction.

The connection terminal pad portion 81 is arranged substantially at the center of the connection portion 2 and the curved portion 3 in plan view (the center in the front-rear direction and the center in the left-right direction). That is, the connection terminal pad portion 81 is arranged so as to straddle both the connection portion 2 and the curved portion 3 . Specifically, the connection terminal pad portion 81 is arranged on the upper surfaces of the base connecting portion 71 and the base bending portion 72 from the center of the connecting portion 2 in the front-rear direction to the center of the bending portion 3 in the front-rear direction.

The connection terminal pad section 81 includes a plurality (two) of connection terminal pads (81a, 81b). That is, the connection terminal pad portion 81 includes a first connection terminal pad 81a and a second connection terminal pad 81b arranged on the right side of the first connection terminal pad 81a with a space therebetween. The first connection terminal pad 81a and the second connection terminal pad 81b are arranged at intervals so as to straddle both the connection portion 2 and the curved portion 3, respectively.

The first connection terminal pad 81a and the second connection terminal pad 81b each have a substantially rectangular shape in plan view. The first connection terminal pad 81 a and the second connection terminal pad 81 b are exposed from the insulating cover layer 9 .

The length (front-rear direction distance) L3 of the first connection terminal pad 81a and the second connection terminal pad 81b is, for example, 50 μm or more, preferably 100 μm or more, and is, for example, 2000 μm or less, preferably 1000 μm. It is below.

The planar view area of the connection terminal pad portion 81 (the total area of the first connection terminal pad 81a and the second connection terminal pad 81b) is, for example, 5000 μm ² or more, preferably 10000 μm ² or more, and is, for example, 10 mm ² . Below, it is preferably 5 mm ² or less.

The length L3 of each of the connection terminal pads 81a and 81b or the plan view area of the connection terminal pad portion 81 refers to the distance in the front-rear direction or the area when projected in the vertical direction.

The planar view area of the connection terminal pad portion 81 is, for example, 50% or more, preferably 60% or more, and for example, 95% or less, preferably 90% of the planar view area of the connection portion 2. It is below. If the plane view area of the connection terminal pad portion 81 is equal to or greater than the lower limit, the area of the connection terminal pad portion 81 can be increased, and a large amount of the bonding material 30 can be placed on the connection terminal pad portion 81 . Therefore, connection reliability can be further improved. Further, if the planar view area of the connection terminal pad portion 81 is equal to or less than the above upper limit, the bonding material 30 can be held on the upper surface of the connection portion 2 when the bonding material 30 spreads outside the connection terminal pad portion 81 . It is possible to suppress contamination around the printed circuit board 1 .

The body terminal pad portion 82 is arranged on the rear side of the circuit body portion 5 . The body terminal pad section 82 includes a plurality (two) of connection terminal pads. That is, the main body terminal pad section 82 includes a first main body terminal pad 82a and a second main body terminal pad 82b spaced apart on the right side thereof. The first body terminal pad 82 a is arranged at the rear left end portion of the circuit body portion 5 , and the second body terminal pad 82 b is arranged at the rear right end portion of the circuit body portion 5 .

Each of the first body terminal pads 82a and the second body terminal pads 82b has a substantially rectangular shape in plan view. The first body terminal pads 82 a and the second body terminal pads 82 b are exposed from the insulating cover layer 9 .

The wiring portion 83 is arranged on the upper surfaces of the base curved portion 72 , the base extension portion 73 and the base body portion 74 so as to connect the connection terminal pad portion 81 and the body terminal pad portion 82 .

The wiring portion 83 includes a first wiring 83a and a second wiring 83b arranged on the right side thereof. The first wiring 83a extends rearward from the rear edge of the first connection terminal pad 81a, and extends rearward along the outer shape of the wired circuit board 1 at the curved portion 3 and the extension portion 4, After bending leftward at the tip of the circuit main body 5 , it extends leftward along the outer shape of the wired circuit board 1 , and bends rearward at the left end of the circuit main body 5 . , extends rearward along the outer shape of the printed circuit board 1 and reaches the tip edge of the first main body terminal pad 82a. The second wiring 83b extends rearward from the rear edge of the second connection terminal pad 81b, extends rearward along the outer shape of the wired circuit board 1 at the curved portion 3 and the extension portion 4, and is connected to the circuit. After bending rightward at the front end of the main body 5, it extends rightward along the outer shape of the wired circuit board 1, and bends rearward at the right end of the circuit main body 5, It extends rearward along the outer shape of the printed circuit board 1 and reaches the tip edge of the second body terminal pad 82b.

The material of the conductor layer 8 can be appropriately selected from, for example, known or commonly used metal conductor materials. Specifically, metal conductor materials include, for example, copper, nickel, gold, solder, and alloys thereof. Preferably, conductor layer 8 is made of copper.

The thickness of the conductor layer 8 is, for example, 1 μm or more, preferably 3 μm or more, and for example, 30 μm or less, preferably 20 μm or less.

The insulating cover layer 9 is arranged on the upper surfaces of the insulating base layer 7 and the wiring portion 83 . Specifically, the insulating cover layer 9 is arranged on the upper surface of the insulating base layer 7 so as to cover the upper surface and side surfaces of the wiring portion 83 . Specifically, the insulating cover layer 9 includes a first insulating cover layer 9a covering the first wiring 83a and a second insulating cover layer 9b covering the second wiring 83b.

The first insulating cover layer 9a is arranged on the upper surfaces of the curved base portion 72, the extended base portion 73, and the main body portion 74 so as to extend from the leading edge of the first wiring 83a to the trailing edge of the first wiring 83a. .

The second insulating cover layer 9b is arranged on the upper surfaces of the curved base portion 72, the extended base portion 73, and the main body portion 74 so as to extend from the leading edge of the second wiring 83b to the trailing edge of the second wiring 83b. .

The material of the insulating cover layer 9 can be appropriately selected from, for example, known or commonly used insulating materials. Specifically, an insulating material similar to that of the insulating base layer 7 can be used. Preferably, the insulating cover layer 9 is made of polyimide resin.

The thickness of the insulating cover layer 9 is, for example, 1 μm or more, preferably 3 μm or more, and for example, 30 μm or less, preferably 20 μm or less.

This wired circuit board 1 is made by, for example, laminating an insulating base layer 7, a conductor layer 8 and an insulating cover layer 9 on the upper surface of a flat (non-bent) metal support layer 6, and then bending this laminated body. It can be manufactured by curving a portion corresponding to the portion 3 so as to have a desired curvature radius R.

2. Bonding of Wired Circuit Board and Electronic Element Next, a method of bonding the wired circuit board 1 to the electronic element 20 will be described with reference to FIGS. 4A to 4D.

As shown in FIG. 4A, an electronic device 20 is provided.

The electronic device 20 comprises a bottom portion 21 and side portions 22 . A side opening 23 is formed in the side surface of the side portion 22 so as to be recessed from the side surface toward the side. An electronic device terminal 24 connected to a wiring (not shown) in the electronic device 20 is arranged above the side opening 23 .

Next, as shown in FIG. 4B, the printed circuit board 1 is placed on the electronic element 20 so that the lower surface of the connection portion 2 (surface on the other side in the thickness direction) is in contact with the bottom portion 21 . Subsequently, the bonding material 30 is arranged on the upper surface of the connection terminal pad portion 81 .

Examples of the bonding material 30 include conductive materials such as solder and conductive adhesives (eg, silver paste).

Next, as shown in FIG. 4C, the printed circuit board 1 is moved toward the front side, and the connecting portion 2 is inserted into the side opening portion 23 . Thereby, the upper surface of the bonding material 30 is brought into contact with the lower surface of the electronic element terminal 24 .

At this time, if the bonding material 30 is heated, the bonding material 30 is solidified by cooling to room temperature.

As a result, the connection terminal pad portions 81 of the wired circuit board 1 are electrically connected to the electronic element terminals 24 via the bonding material 30 , and the wired circuit board 1 is fixed to the electronic element 20 . That is, the printed circuit board 1 is joined to the electronic element 20 .

After that, as shown in FIG. 4D, the external element 35 is bonded to the main body terminal pad portion 82, if necessary. That is, the external element 35 is electrically connected to the body terminal pad portion 82 via the bonding material 30 .

As a result, the substrate-bonded electronic device 40 including the electronic element 20, the external element 35, and the wired circuit board 1 electrically connected thereto is obtained.

3. Applications of Wired Circuit Board The wired circuit board 1 is used in various applications such as a circuit board for electronic devices and a circuit board for electric devices. Such circuit boards for electronic components and circuit boards for electrical components include, for example, circuit boards (circuit boards for sensors) used in various sensors such as position information sensors, obstacle detection sensors, temperature sensors, automobiles, trains, Circuit boards used in various transport vehicles such as aircraft and work vehicles (circuit boards for transport vehicles), circuit boards used in various video equipment such as flat panel displays, flexible displays, and projection video equipment (circuit boards for video equipment) , various network devices, circuit boards used in various communication relay devices such as large communication devices (circuit boards for communication relay devices), circuit boards used in information processing terminals such as computers, tablets, smartphones, home games (information processing circuit boards for terminals), circuit boards used in movable devices such as drones and robots (circuit boards for movable devices), circuit boards used in various medical devices such as wearable medical devices and medical diagnostic devices (medical Circuit boards for electrical equipment), circuit boards used in various electrical equipment such as refrigerators, washing machines, vacuum cleaners, and air conditioners (circuit boards for electrical equipment), circuits used in various recording electronic equipment such as digital cameras and DVD recorders Substrates (circuit substrates for video recording electronic devices) and the like.

The wired circuit board 1 includes a connection portion 2 having a planar shape extending in the direction of the first plane, a curved portion 3 continuous with the connection portion 2 , and an extension portion 4 continuous with the curved portion 3 . The connecting portion 2 includes a metal supporting layer 6 , an insulating base layer 7 arranged above the metal supporting layer 6 , and a connection terminal pad portion 81 arranged above the insulating base layer 7 .

Therefore, even if the bonding material 30 gets wet and spreads when a large amount of the bonding material 30 is placed on the connection terminal pad portion 81 , the bonding material 30 is blocked by the curved portion 3 . In particular, as shown in FIGS. 4B and 4C, when the printed circuit board 1 is quickly moved forward, the bonding material 30 relatively moves backward due to the law of inertia. However, due to the slope of the curved portion 3, the movement of the bonding material 30 is slight (see the phantom line). Further, after being moved, the bonding material 30 tends to return to its original position due to the slope of the curved portion 3 . Therefore, the bonding material 30 does not wet and spread to the extended portion 4 (and thus the circuit body portion 5), and contamination of the surrounding area by the bonding material 30 can be suppressed.

Moreover, since a large amount of bonding material 30 can be placed on the connection terminal pad portion 81 and connected to the terminals 24 of the electronic element 20, connection reliability can be improved.

On the other hand, as shown in FIGS. 5A and 5B, when a conventional printed circuit board without the curved portion 3 is used, the bonding material 30 excessively wets and spreads rearward during movement. As a result, the surrounding area is contaminated, and connection between the connection terminal pads of the printed circuit board and the electronic element terminals 24 becomes difficult. Also, as shown in FIGS. 6A and 6B, if a printed circuit board having a right angle portion 50 is used instead of the curved portion 3, an air pocket 51 is generated inside the bonding material 30 near the right angle portion 50 after movement. As a result, the contact area of the connection terminal pad is reduced and the connection reliability is lowered. In addition, the reflow process or the like may expand the air reservoir 51 and damage the bonding material 30 .

Moreover, in the wired circuit board 1 , the connection terminal pad portion 81 is arranged so as to straddle both the connection portion 2 and the curved portion 3 .

Therefore, even the bonding material 30 that has wetted and spread to the curved portion 3 can come into contact with the connection terminal pad portion 81, so that the bonding material 30 can be effectively used. Therefore, connection reliability can be further improved.

4. Modifications In one embodiment shown in FIGS. 1 to 3, the connecting portion 2 does not have openings, but for example, although not shown, the connecting portion 2 includes a connection terminal pad portion 81, a base connection portion 71 and a support. The connecting portion 61 can also be provided in an opening penetrating in the thickness direction.

In one embodiment shown in FIGS. 1 to 3, in the connection terminal pad section 81, the first connection terminal pad 81a and the second connection terminal pad 81b do not have a plating layer, but for example, although not shown, a second connection terminal pad 81b The first connection terminal pad 81a and the second connection terminal pad 81b can also have a plating layer covering their surfaces (upper surface and side surfaces).

Examples of the plated layer include an Au plated layer, a Ni plated layer, a combination thereof, and the like.

Similarly, the body terminal pad portion 82 can also have a plated layer.

In one embodiment shown in FIGS. 1 to 3, the circuit body portion 5 has a third surface extending in the second surface direction. It can have a third surface extending (eg, in the direction of the first surface). In this case, between the front end edge of the circuit main body 5 and the rear end edge of the extension portion 4, a curved portion 3 having an upwardly convex shape is further arranged.

In one embodiment shown in FIGS. 1 to 3, the wired circuit board 1 includes one connecting portion 2 and one curved portion 3 and extending portion 4 continuous therewith. The substrate 1 may also comprise a plurality of connecting portions 2 followed by a plurality of bends 3 and extensions 4 .

In one embodiment shown in FIGS. 1 to 3, the connection terminal pad section 81 includes a plurality (two) of connection terminal pads 81a and 81b. For example, although not shown, the connection terminal pad section 81 may Only one connection terminal pad may be provided, or three or more connection terminal pads may be provided.

Further, the electronic element 20 may be a device or component independent of the wired circuit board 1, or may constitute one device or component together with the wired circuit board 1. FIG. Also, the shape of the electronic element 20 is not particularly limited as long as it can be connected to the printed circuit board 1 .

<Second embodiment>
One embodiment of the printed circuit board according to the second embodiment of the present invention will be described with reference to FIG. In addition, in 2nd Embodiment, the same code|symbol is attached|subjected to the member similar to above-described 1st Embodiment, and the description is abbreviate|omitted.

In the first embodiment, the connection terminal pad portion 81 is arranged so as to straddle both the connection portion 2 and the curved portion 3. However, as shown in FIG. The connection terminal pad portion 81 is arranged only on the connection portion 2 . Specifically, the connection terminal pad portion 81 is arranged substantially at the central portion of the connection portion 2 in plan view.

In the second embodiment, the bending portion 3 comprises a metal support layer 6 , an insulating base layer 7 , a wiring portion 83 and an insulating cover layer 9 . Specifically, the bending portion 3 includes a supporting bending portion 62 , a base bending portion 72 , a tip portion of the wiring portion 83 , and a tip portion of the insulating cover layer 9 .

Also about 2nd Embodiment, there exists an effect similar to 1st Embodiment.

The first embodiment is preferable from the viewpoint that the bonding material 30 that has wetted and spread to the curved portion 3 can come into contact with the connection terminal pad portion 81 and the bonding material 30 can be effectively used.

The modification of the first embodiment can also be applied to the second embodiment.

Reference Signs List 1 wired circuit board 2 connection portion 3 bending portion 4 extension portion 20 electronic element 81 connection terminal pad portion

Claims (2)

a connecting portion having a planar shape extending in a plane direction;
a curved portion continuous with the connecting portion;
an extending portion continuous with the curved portion,
The connecting part is
a metal support layer;
an insulating layer arranged on one side in the thickness direction of the metal support layer;
A pad portion disposed on one side in the thickness direction of the insulating layer and electrically connected to an electronic element,
The curved portion includes the metal support layer and the insulating layer,
The curved portion has a convex shape toward the other side in the thickness direction,
The printed circuit board, wherein the pad section is arranged so as to straddle both the connecting section and the curved section . 2. The printed circuit board according to claim 1, wherein the planar view area of the pad portion is 50% or more of the planar view area of the connection portion.

Images