JP2020136673A - Wiring board and manufacturing method thereof - Google Patents

Abstract

To provide a wiring board and a manufacturing method thereof that alleviate stress that acts on a connection between wiring and an electronic component as the wiring board expands and contracts.SOLUTION: A wiring board 10 includes: a base material 20 including a first surface 21 and a second surface 22 on the opposite side to the first surface, and having elasticity in at least a first direction from among surface directions along the first surface and the second surface; wiring 52 located on the first surface side and connected to at least one electronic component 51 mounted on the wiring board; and a reinforcing member 30 which is located apart from the electronic component in the surface direction and reinforces the base material. At least a part of the reinforcing member extends at least from the position of a first end 511 of the electronic component in a first direction D1 to the position of a second end 512 facing the first end in the first direction.SELECTED DRAWING: Figure 1

Description

An embodiment of the present disclosure relates to a wiring board including a stretchable base material and wiring. Moreover, the embodiment of this disclosure relates to the manufacturing method of the wiring board.

In recent years, research has been conducted on electronic devices having deformability such as elasticity. For example, there are known ones in which elastic silver wiring is formed on an elastic base material and one in which horseshoe-shaped wiring is formed on an elastic base material (see, for example, Patent Document 1).

As another type of electronic device, for example, Patent Document 2 discloses a wiring board having a base material and wiring provided on the base material, and having elasticity. Patent Document 2 employs a manufacturing method in which a circuit is provided on a pre-stretched base material, and the base material is relaxed after the circuit is formed. Patent Document 2 employs a manufacturing method in which a circuit is provided on a pre-stretched base material, and the base material is relaxed after the circuit is formed.

Japanese Unexamined Patent Publication No. 2013-187308 JP-A-2007-281406

However, in Patent Documents 1 and 2, no effective proposal has been made for relaxing the stress acting on the connection portion between the wiring and the electronic component due to the expansion and contraction of the wiring board.

An object of the present disclosure is to provide a wiring board and a method for manufacturing a wiring board that can effectively solve such a problem.

One embodiment of the present disclosure is a wiring board, which has a first surface and a second surface opposite to the first surface, and has at least one of the first surface and the surface direction along the second surface. A base material having elasticity in the first direction, wiring located on the first surface side and connected to at least one electronic component mounted on the wiring board, and wiring in the surface direction with respect to the electronic component. A reinforcing member that is located apart and reinforces the base material is provided, and at least a part of the reinforcing member is the first in the first direction from the position of the first end portion of the electronic component in the first direction. It is a wiring board that extends at least to the position of the second end portion facing the first end portion.

The reinforcing member may have a shape surrounding the electronic component when viewed from the normal direction of the first surface.

The reinforcing member may have a shape that surrounds the entire circumference of the electronic component when viewed from the normal direction.

The reinforcing member may have a shape that partially surrounds the electronic component when viewed from the normal direction.

The reinforcing member may have a flexural rigidity higher than the rigidity of the base material.

The reinforcing member may have an elastic modulus larger than the elastic modulus of the base material.

The reinforcing member may be located on the wiring or on the first surface.

The reinforcing member may be located between the first surface and the wiring or on the first surface.

The reinforcing member may be embedded inside the base material.

The reinforcing member may be located on the second surface.

The wiring may have a longitudinal direction along the first direction.

The wiring may have a bellows-shaped portion including a plurality of peaks and valleys arranged along the longitudinal direction.

The wiring board may further include a support board that is located between the first surface and the wiring and supports the wiring.

One embodiment of the present disclosure is a method of manufacturing a wiring board, which has a first surface and a second surface opposite to the first surface, and has a surface direction along the first surface and the second surface. Of these, a stretching step of applying tensile stress in the first direction to a base material having elasticity in at least the first direction to stretch the base material, and a stretching step on the first surface side of the stretched base material. The first installation step of providing wiring connected to at least one electronic component mounted on the wiring board, and reinforcement for reinforcing the base material so as to be located apart from the electronic component in the plane direction. A second installation step of providing a member is provided, and in the second installation step, at least a part of the reinforcing member is said to be the first in the first direction from the position of the first end portion of the electronic component in the first direction. This is a method for manufacturing a wiring board, which comprises providing the reinforcing member so as to extend at least to the position of the second end portion facing the first end portion.

According to the embodiment of the present disclosure, it is possible to relax the stress acting on the connection portion between the wiring and the electronic component due to the expansion and contraction of the wiring board.

It is a top view which shows the wiring board which concerns on embodiment. It is sectional drawing which shows the case where the wiring board of FIG. 1 is cut along the line II-II. It is sectional drawing which shows the wiring board shown in FIG. 2 enlarged. It is sectional drawing which shows one modification of the wiring board. It is a figure for demonstrating the manufacturing method of the wiring board shown in FIG. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board. It is a top view which shows one modification of the wiring board. It is a top view which shows one modification of the wiring board. It is a top view which shows one modification of the wiring board. It is sectional drawing which shows one modification of the wiring board.

Hereinafter, the configuration of the wiring board and the manufacturing method thereof according to the embodiment of the present disclosure will be described in detail with reference to the drawings. The embodiments shown below are examples of the embodiments of the present disclosure, and the present disclosure is not construed as being limited to these embodiments. Further, in the present specification, terms such as "board", "base material", "sheet" and "film" are not distinguished from each other based only on the difference in names. For example, "base material" is a concept that includes members that can be called substrates, sheets, or films. Furthermore, as used herein, terms such as "parallel" and "orthogonal" and values of length and angle that specify the shape and geometric conditions and their degrees are bound by strict meaning. Instead, the interpretation will include the range in which similar functions can be expected. Further, in the drawings referred to in the present embodiment, the same parts or parts having similar functions are designated by the same reference numerals or similar reference numerals, and the repeated description thereof may be omitted. In addition, the dimensional ratio of the drawing may differ from the actual ratio for convenience of explanation, or a part of the configuration may be omitted from the drawing.

(Wiring board)
First, the configuration of the wiring board 10 according to the present embodiment will be described. FIG. 1 is a plan view showing a wiring board 10 according to the present embodiment. FIG. 2 is a cross-sectional view of the wiring board 10 of FIG. 1 cut along the lines II-II.

The wiring board 10 includes a base material 20, a reinforcing member 30, an electronic component 51, and a wiring 52. Hereinafter, each component of the wiring board 10 will be described.

〔Base material〕
The base material 20 is a member configured to have elasticity. The base material 20 has a first surface 21 located on the side of the electronic component 51 and the wiring 52, and a second surface 22 located on the opposite side of the first surface 21. The base material 20 has elasticity in at least the first direction D1 among the plane directions along the first surface 21 and the second surface 22. The first direction D1 may be, for example, the longitudinal direction of the base material 20. The thickness of the base material 20 is, for example, 10 μm or more and 10 mm or less, and more preferably 20 μm or more and 3 mm or less. By setting the thickness of the base material 20 to 10 μm or more, the durability of the base material 20 can be ensured. Further, by reducing the thickness of the base material 20 to 10 mm or less, the mounting comfort of the wiring board 10 can be ensured. If the thickness of the base material 20 is made too small, the elasticity of the base material 20 may be impaired.

The elasticity of the base material 20 means that the base material 20 can expand and contract, that is, it can be expanded from a normal non-extended state and can be restored when released from this extended state. The property that can be done. The non-extended state is the state of the base material 20 when no tensile stress is applied. In the present embodiment, the stretchable substrate can preferably be stretched by 1% or more from the non-stretched state without being destroyed, more preferably 20% or more, and further preferably 75%. It can be extended as described above. By using the base material 20 having such an ability, the wiring board 10 can have elasticity as a whole. Further, the wiring board 10 can be used in products and applications that require high expansion and contraction, such as being attached to a part of the body such as a human arm. It is generally said that a product mounted under the armpit of a person needs to have an elasticity of 72% in the vertical direction and 27% in the horizontal direction. In addition, for products attached to human knees, elbows, buttocks, ankles, and armpits, 26% or more and 42% in the vertical direction.
It is said that the following elasticity is required. It is also said that products that are attached to other parts of the human body need to have less than 20% elasticity.

Further, it is preferable that the difference between the shape of the base material 20 in the non-stretched state and the shape of the base material 20 when the base material 20 is stretched from the non-stretched state and then returned to the non-stretched state is small. This difference is also referred to as a shape change in the following description. The shape change of the base material 20 is, for example, 20% or less, more preferably 10% or less, still more preferably 5% or less in terms of area ratio. By using the base material 20 having a small shape change, the bellows-shaped portion described later can be easily formed.

An example of a parameter representing the elasticity of the base material 20 is the elastic modulus of the base material 20. The elastic modulus of the base material 20 is, for example, 10 MPa or less, more preferably 1 MPa or less. By using the base material 20 having such an elastic modulus, the entire wiring board 10 can be made elastic. The elastic modulus of the base material 20 may be 1 kPa or more.

As a method for calculating the elastic modulus of the base material 20, a method of carrying out a tensile test in accordance with JIS K6251 using a sample of the base material 20 can be adopted. It is also possible to adopt a method in which the elastic modulus of the sample of the base material 20 is measured by the nanoindentation method in accordance with ISO14577. A nanoindenter can be used as the measuring instrument used in the nanoindentation method. As a method of preparing a sample of the base material 20, a method of taking out a part of the base material 20 from the wiring board 10 as a sample and a method of taking out a part of the base material 20 before forming the wiring board 10 as a sample can be considered. Be done. In addition, as a method of calculating the elastic modulus of the base material 20, a method of analyzing the materials constituting the base material 20 and calculating the elastic modulus of the base material 20 based on the existing database of the materials is adopted. You can also. The elastic modulus in the present application is an elastic modulus in an environment of 25 ° C.

Another example of a parameter representing the elasticity of the base material 20 is the flexural rigidity of the base material 20. The flexural rigidity is the product of the moment of inertia of area of the target member and the elastic modulus of the material constituting the target member, and the unit is N · m ² or Pa · m ⁴ . The moment of inertia of area of the base material 20 is calculated based on the cross section when the portion of the base material 20 that overlaps with the wiring 52 is cut by a plane orthogonal to the expansion / contraction direction of the wiring board 10.

Examples of the material constituting the base material 20 include an elastomer. Further, as the material of the base material 20, for example, a cloth such as a woven fabric, a knitted fabric, or a non-woven fabric can be used. As the elastomer, general thermoplastic elastomers and thermosetting elastomers can be used, and specifically, polyurethane-based elastomers, styrene-based elastomers, nitrile-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, ester-based elastomers, etc. Amid-based elastomers, 1,2-BR-based elastomers, fluoroelastomers, silicone rubbers, urethane rubbers, fluororubbers, polybutadienes, polyisobutylenes, polystyrene butadienes, polychloroprenes and the like can be used. Considering mechanical strength and abrasion resistance, it is preferable to use a urethane-based elastomer. Further, the base material 20 may contain silicone. Silicone is excellent in heat resistance, chemical resistance, and flame retardancy, and is preferable as a material for the base material 20.

〔wiring〕
The wiring 52 has conductivity and is a member used for input / output of an electric signal by the electronic component 51. In the examples shown in FIGS. 1 and 2, the wiring 52 is located on the first surface 21 and has a longitudinal direction along the first direction D1 in which the base material 20 expands and contracts.

As will be described later, the wiring 52 is provided on the base material 20 in a state of being stretched by tensile stress. When the tensile stress is removed from the base material 20 and the base material 20 contracts, the wiring 52 is deformed into a bellows shape except in the expansion / contraction suppressing region A described later, and has a bellows-shaped portion 57.

FIG. 3 is an enlarged cross-sectional view of the wiring board 10 shown in FIG. As shown in FIG. 3, the bellows-shaped portion 57 includes peaks and valleys in the normal direction of the first surface 21 of the base material 20. In FIG. 3, reference numeral 53 represents a mountain portion appearing on the front surface of the wiring 52, and reference numeral 54 represents a mountain portion appearing on the back surface of the wiring 52. Further, reference numeral 55 represents a valley portion appearing on the front surface of the wiring 52, and reference numeral 56 represents a valley portion appearing on the back surface of the wiring 52. The front surface is a surface of the wiring 52 located on the side farther from the base material 20, and the back surface is a surface of the wiring 52 located on the side closer to the base material 20. Further, in FIG. 3, reference numerals 26 and 27 represent peaks and valleys appearing on the first surface 21 of the base material 20. When the base material 20 is deformed so that the mountain portion 26 and the valley portion 27 appear on the first surface 21, the wiring 52 is deformed in a bellows shape to have the bellows-shaped portion 57. The peak 26 of the first surface 21 of the base material 20 corresponds to the peaks 53 and 54 of the bellows shape portion 57 of the wiring 52, and the valley portion 27 of the first surface 21 of the base material 20 corresponds to the bellows shape of the wiring 52. It corresponds to the valley portions 55 and 56 of the portion 57. Note that FIG. 3 shows an example in which a plurality of peaks and valleys of the bellows-shaped portion 57 are lined up at a constant period F1, but the present invention is not limited to this. Although not shown, the plurality of peaks and valleys of the bellows-shaped portion 57 may be arranged irregularly along the longitudinal direction D1 of the wiring 52. For example, the distance between two adjacent peaks in the longitudinal direction D1 does not have to be constant.

In FIG. 3, reference numeral S1 represents the amplitude of the bellows-shaped portion 57 on the surface of the wiring 52 in the normal direction of the base material 20. The amplitude S1 is, for example, 1 μm or more, more preferably 10 μm or more. By setting the amplitude S1 to 10 μm or more, the wiring 52 is easily deformed following the elongation of the base material 20. Further, the amplitude S1 may be, for example, 500 μm or less.

The amplitude S1 measures, for example, the distance in the normal direction of the first surface 21 between the adjacent peaks 53 and the valleys 55 over a certain range in the length direction of the wiring 52, and averages them. It is calculated by finding it. The "constant range in the length direction of the wiring 52" is, for example, 10 mm. As the measuring instrument for measuring the distance between the adjacent peaks 53 and the valleys 55, a non-contact measuring instrument using a laser microscope or the like may be used, or a contact measuring instrument may be used. .. Further, the distance between the adjacent mountain portion 53 and the valley portion 55 may be measured based on an image such as a cross-sectional photograph. The calculation method of the amplitudes S2, S3, and S4 described later is also the same.

In FIG. 3, reference numeral S2 represents the amplitude of the bellows-shaped portion 57 on the back surface of the wiring 52. The amplitude S2 is, for example, 1 μm or more, more preferably 10 μm or more, like the amplitude S1. Further, the amplitude S2 may be, for example, 500 μm or less. Further, in FIG. 3, reference numeral S3 represents the amplitude of the peak portion 26 and the valley portion 27 appearing on the first surface 21 of the base material 20 at the portion overlapping the bellows-shaped portion 57. When the back surface of the wiring 52 is located on the first surface 21 of the base material 20 as shown in FIG. 3, the amplitude S3 of the peaks 26 and the valleys 27 of the first surface 21 of the base material 20 is the wiring 52. It is equal to the amplitude S2 of the bellows-shaped portion 57 on the back surface of.

Although FIG. 3 shows an example in which the bellows-shaped portion does not appear on the second surface 22 of the base material 20, the present invention is not limited to this. As shown in FIG. 4, the bellows-shaped portion may also appear on the second surface 22 of the base material 20. In FIG. 4, reference numerals 28 and 29 represent peaks and valleys appearing on the second surface 22 of the base material 20. In the example shown in FIG. 4, the mountain portion 28 of the second surface 22 appears at a position overlapping the valley portion 27 of the first surface 21, and the valley portion 29 of the second surface 22 is formed on the mountain portion 26 of the first surface 21. Appears in overlapping positions. Although not shown, the positions of the peaks 28 and the valleys 29 of the second surface 22 of the base material 20 do not have to overlap the valleys 27 and 26 of the first surface 21. Further, the number or period of the peaks 28 and 29 of the second surface 22 of the base material 20 may be the same as or different from the number or period of the peaks 26 and 27 of the first surface 21. You may. For example, the period of the peak 28 and the valley 29 of the second surface 22 of the base material 20 may be larger than the period of the peak 26 and the valley 27 of the first surface 21. In this case, the period of the peaks 28 and the valleys 29 of the second surface 22 of the base material 20 may be 1.1 times or more the period of the peaks 26 and the valleys 27 of the first surface 21. . It may be 2 times or more, 1.5 times or more, or 2.0 times or more. It should be noted that "the period of the peaks 28 and the valleys 29 of the second surface 22 of the base material 20 is larger than the period of the peaks 26 and the valleys 27 of the first surface 21" is the second of the base material 20. This is a concept including the case where the peaks and valleys do not appear on the surface 22.

In FIG. 4, reference numeral S4 represents the amplitude of the peak 28 and the valley 29 appearing on the second surface 22 of the base material 20 at the portion overlapping the bellows-shaped portion 57. The amplitude S4 of the second surface 22 may be the same as or different from the amplitude S3 of the first surface 21. For example, the amplitude S4 of the second surface 22 may be smaller than the amplitude S3 of the first surface 21. For example, the amplitude S4 of the second surface 22 may be 0.9 times or less, 0.8 times or less, or 0.6 times or less the amplitude S3 of the first surface 21. Good. Further, the amplitude S4 of the second surface 22 may be 0.1 times or more, or 0.2 times or more, the amplitude S3 of the first surface 21. When the thickness of the base material 20 is small, the ratio of the amplitude S4 of the second surface 22 to the amplitude S3 of the first surface 21 tends to be large. It should be noted that "the amplitude of the peaks 28 and the valleys 29 of the second surface 22 of the base material 20 is smaller than the amplitudes of the peaks 26 and the valleys 27 of the first surface 21" is the second of the base material 20. This is a concept including the case where the peaks and valleys do not appear on the surface 22.

Further, in FIG. 4, an example is shown in which the positions of the peaks 28 and 29 of the second surface 22 match the positions of the valleys 27 and 26 of the first surface 21, but the present invention is limited to this. There is no such thing.

The material of the wiring 52 may be any material that can follow the expansion and contraction of the base material 20 by utilizing the elimination and formation of the bellows-shaped portion 57. The material of the wiring 52 may or may not have elasticity by itself. Examples of the material that can be used for the wiring 52 and does not have elasticity by itself include metals such as gold, silver, copper, aluminum, platinum, and chromium, and alloys containing these metals. When the material of the wiring 52 itself does not have elasticity, a metal film can be used as the wiring 52. When the material itself used for the wiring 52 has elasticity, the elasticity of the material is similar to, for example, the elasticity of the base material 20. Examples of the material that can be used for the wiring 52 and has elasticity by itself include a conductive composition containing conductive particles and an elastomer. The conductive particles may be any particles that can be used for wiring, and examples thereof include particles of gold, silver, copper, nickel, palladium, platinum, carbon and the like. Of these, silver particles are preferably used.

Preferably, the wiring 52 has a structure that is resistant to deformation. For example, the wiring 52 has a base material and a plurality of conductive particles dispersed in the base material. In this case, by using a deformable material such as resin as the base material, the wiring 52 can also be deformed according to the expansion and contraction of the base material 20. Further, the conductivity of the wiring 52 can be maintained by setting the distribution and shape of the conductive particles so that the contact between the plurality of conductive particles is maintained even when the deformation occurs. ..

As a material constituting the base material of the wiring 52, general thermoplastic elastomers and thermocurable elastomers can be used. For example, styrene-based elastomers, acrylic-based elastomers, olefin-based elastomers, urethane-based elastomers, silicone rubbers, etc. Elastomer rubber, fluororubber, nitrile rubber, polybutadiene, polychloroprene and the like can be used. Among them, resins and rubbers containing urethane-based and silicone-based structures are preferably used in terms of their elasticity and durability. Further, as a material constituting the conductive particles of the wiring 52, for example, particles such as silver, copper, gold, nickel, palladium, platinum, and carbon can be used. Of these, silver particles are preferably used.

The thickness of the wiring 52 may be a thickness that can withstand the expansion and contraction of the base material 20, and is appropriately selected depending on the material of the wiring 52 and the like. For example, when the material of the wiring 52 does not have elasticity, the thickness of the wiring 52 can be in the range of 25 nm or more and 50 μm or less, preferably in the range of 50 nm or more and 10 μm or less, and preferably 100 nm or more and 5 μm. It is more preferably within the following range. When the material of the wiring 52 has elasticity, the thickness of the wiring 52 can be in the range of 5 μm or more and 60 μm or less, preferably in the range of 10 μm or more and 50 μm or less, and 20 μm or more and 40 μm or less. It is more preferable that it is within the range. The width of the wiring 52 is, for example, 50 μm or more and 10 mm or less.

The method for forming the wiring 52 is appropriately selected depending on the material and the like. For example, a method of forming a metal film on the base material 20 or a support substrate 40 described later by a vapor deposition method, a sputtering method, or the like and then patterning the metal film by a photolithography method can be mentioned. Alternatively, a method of patterning a metal film by a photolithography method after adhering and laminating a Cu foil on a support substrate 40 can be mentioned. When the material of the wiring 52 itself has elasticity, for example, the conductive composition containing the above-mentioned conductive particles and elastomer is patterned on the base material 20 or the support substrate 40 by a general printing method. There is a method of printing. Of these methods, a printing method that has high material efficiency and can be manufactured at low cost can be preferably used.

The advantage that the bellows-shaped portion 57 is formed in the wiring 52 will be described. As described above, the base material 20 has an elastic modulus of 10 MPa or less. Therefore, when tensile stress is applied to the wiring board 10, the base material 20 can be stretched by elastic deformation. Here, if the wiring 52 is similarly stretched by elastic deformation, the total length of the wiring 52 increases and the cross-sectional area of the wiring 52 decreases, so that the resistance value of the wiring 52 increases. Further, it is also conceivable that the wiring 52 may be damaged such as cracks due to the elastic deformation of the wiring 52. On the other hand, in the present embodiment, the wiring 52 has a bellows-shaped portion 57. Therefore, when the base material 20 is stretched, the wiring 52 follows the elongation of the base material 20 by deforming the bellows-shaped portion 57 so as to reduce the undulations, that is, by eliminating the bellows shape. Can be done. Therefore, it is possible to prevent the total length of the wiring 52 from increasing and the cross-sectional area of the wiring 52 from decreasing as the base material 20 stretches. As a result, it is possible to suppress an increase in the resistance value of the wiring 52 due to the extension of the wiring board 10. Further, it is possible to prevent the wiring 52 from being damaged such as a crack.

[Electronic components]
The electronic component 51 is located on the first surface 21 side and is electrically connected to the wiring 52 via the conductive connecting portion 51a. In the example shown in FIG. 2, the wiring 52 is the first end portion 511 of the electronic component 51 in the first direction D1 and the electronic component 51 facing the first end portion 511 in the first direction D1 via the connection portion 51a. It is connected to two ends 512. The connecting portion 51a may be a solder, a conductive adhesive, or the like. The electronic component 51 may be an active component, a passive component, or a mechanical component. Note that the wiring 52 is not limited to the case where the wiring 52 is connected to each of the two ends 511 and 512 and arranged to face each other in the first direction D1 as shown in FIG. 2, for example, the two ends 511 and 512. It may be connected to only one of them, or may not be arranged to face each other in the first direction D1.

Examples of electronic components 51 include transistors, LSI (Large-Scale Integration), MEMS (Micro Electro Mechanical Systems), relays, light emitting elements such as LEDs, OLEDs, and LCDs, sound components such as sensors and buzzers, and vibrations that generate vibrations. Examples thereof include parts, cold and heat-generating parts such as Perche elements and heating wires that control cooling heat generation, resistors, capacitors, inductors, piezoelectric elements, switches, and connectors. Of the above examples of the electronic component 51, the sensor is preferably used. Examples of sensors include temperature sensors, pressure sensors, optical sensors, photoelectric sensors, proximity sensors, shear force sensors, biosensors, laser sensors, microwave sensors, humidity sensors, strain sensors, gyro sensors, acceleration sensors, displacement sensors, etc. Examples thereof include magnetic sensors, gas sensors, GPS sensors, ultrasonic sensors, odor sensors, brain wave sensors, current sensors, vibration sensors, pulse wave sensors, electrocardiographic sensors, and photometric sensors. Of these sensors, biosensors are particularly preferred. The biosensor can measure biometric information such as heartbeat, pulse, electrocardiogram, blood pressure, body temperature, and blood oxygen concentration.

[Reinforcing member]
The reinforcing member 30 has a structure provided on the wiring board 10 in order to relieve the stress of the connecting portion 51a due to the expansion and contraction of the wiring board 10 by reinforcing the base material 20. The reinforcing member 30 is located apart from the electronic component 51 in the surface direction. At least a part of the reinforcing member 30 extends from the position of the first end portion 511 of the electronic component 51 to the position of the second end portion 512.

In the example shown in FIG. 1, the reinforcing member 30 is from the first end portion 511 side in the first direction D1 of the electronic component 51 with respect to the first end portion 511, and is in the first direction from the second end portion 512 of the electronic component 51. It is continuously provided up to the second end 512 side in D1.

Further, in the example shown in FIG. 1, the reinforcing member 30 has a shape surrounding the electronic component 51 when viewed from the normal direction of the first surface 21, that is, in a plan view. More specifically, the reinforcing member 30 has a circular shape surrounding the entire circumference of the electronic component 51 in a plan view. Further, the reinforcing member 30 is located on the wiring 52 or the first surface 21.

As the separation distance between the electronic component 51 and the reinforcing member 30 in the plane direction, a suitable distance is adopted to alleviate the stress acting on the connection portion 51a between the wiring 52 and the electronic component 51 as the base material 20 expands and contracts. can do. For example, the separation distance between the electronic component 51 and the reinforcing member 30 in the plane direction is 0.1 mm or more and 5 mm or less.

The reinforcing member 30 may have an elastic modulus larger than the elastic modulus of the base material 20. The elastic modulus of the reinforcing member 30 is, for example, 10 GPa or more and 500 GPa or less, and more preferably 1 GPa or more and 300 GPa or less. If the elastic modulus of the reinforcing member 30 is too low, it may be difficult to control the expansion and contraction of the base material 20. Further, if the elastic modulus of the reinforcing member 30 is too high, the reinforcing member 30 may be damaged in structure such as cracks and cracks when the base material 20 expands and contracts. The elastic modulus of the reinforcing member 30 may be 1.1 times or more and 1,000,000 times or less of the elastic modulus of the base material 20, and more preferably 10 times or more and 300,000 times or less.

By providing such a reinforcing member 30 on the base material 20, it is possible to prevent the expansion / contraction suppressing region A of the base material 20 from expanding / contracting. The expansion / contraction suppression region A is a region of the base material 20 adjacent to the reinforcing member 30 in a direction intersecting the extending direction of the reinforcing member 30, and includes a region in which the electronic component 51 is located. In the example shown in FIG. 1, the expansion / contraction suppression region A is a region surrounded by the reinforcing member 30.

By suppressing the expansion and contraction of the expansion and contraction suppression region A, the stress acting on the connection portion 51a between the wiring 52 and the electronic component 51 due to the expansion and contraction of the wiring board 10 can be relaxed. By relaxing the stress acting on the connection portion 51a, it is possible to prevent disconnection of the wiring 52 and poor connection between the wiring 52 and the electronic component 51.

Further, by providing the reinforcing member 30 so as to surround the entire circumference of the electronic component 51, even when the base material 20 expands and contracts in a plurality of directions in the plane direction, the wiring 52 and the electrons are expanded and contracted in each direction. The stress acting on the connection portion 51a with the component 51 can be effectively relieved.

The method for calculating the elastic modulus of the reinforcing member 30 is appropriately determined according to the form of the reinforcing member 30. For example, the method of calculating the elastic modulus of the reinforcing member 30 may be the same as or different from the method of calculating the elastic modulus of the base material 20 described above. The elastic modulus of the support substrate 40 described later is also the same. For example, as a method for calculating the elastic modulus of the reinforcing member 30 or the supporting substrate 40, a method of performing a tensile test in accordance with ASTM D882 using a sample of the reinforcing member 30 or the supporting substrate 40 can be adopted. ..

A metal material can be used as the material constituting the reinforcing member 30. Examples of metal materials include copper, aluminum, stainless steel and the like. Further, as a material constituting the reinforcing member 30, a general thermoplastic elastomer, an acrylic-based, urethane-based, epoxy-based, polyester-based, epoxy-based, vinyl ether-based, polyene-thiol-based or silicone-based oligomer, polymer, etc. May be used. When the material constituting the reinforcing member 30 is these resins, the reinforcing member 30 may have transparency. Further, the reinforcing member 30 may have a light-shielding property, for example, a property of shielding ultraviolet rays. For example, the reinforcing member 30 may be black. Further, the color of the reinforcing member 30 and the color of the base material 20 may be the same. The thickness of the reinforcing member 30 is, for example, 1 μm or more and 500 μm or less.

The characteristic of the reinforcing member 30 may be expressed by flexural rigidity instead of the elastic modulus. The moment of inertia of area of the reinforcing member 30 is calculated based on the cross section when the reinforcing member 30 is cut by a plane orthogonal to the expansion / contraction direction of the wiring board 10. The bending rigidity of the reinforcing member 30 may be 1.1 times or more, more preferably 2 times or more, and further preferably 10 times or more the bending rigidity of the base material 20.

The method for forming the reinforcing member 30 is appropriately selected depending on the material and the like. For example, a method of forming a metal film on the base material 20 or the wiring 52 by a vapor deposition method, a sputtering method, or the like, and then patterning the metal film by a photolithography method can be mentioned. Another method is to form a resin film such as an organic layer on the entire surface of the base material 20 or the wiring 52 by a printing method such as a spin coating method, and then pattern the resin film by a photolithography method. Further, for example, a method of printing the material of the reinforcing member 30 in a pattern on the base material 20 or the wiring 52 by a general printing method can be mentioned. Of these methods, a printing method that has high material efficiency and can be manufactured at low cost can be preferably used.

(Manufacturing method of wiring board)
Hereinafter, a method of manufacturing the wiring board 10 will be described with reference to FIGS. 5A to 5D.

First, as shown in FIG. 5A, a base material preparation step for preparing the base material 20 having elasticity is carried out.

After carrying out the base material preparation step, as shown in FIG. 5B, an elongation step of applying a tensile stress T in the first direction D1 to the base material 20 to extend the base material 20 is carried out. After performing the stretching step, the first installation step of providing the wiring 52 having the longitudinal direction along the stretching direction of the base material 20 on the first surface 21 of the base material 20 stretched by the tensile stress T, and the connecting portion. A connection step of connecting the electronic component 51 to the wiring 52 via the 51a is performed.

After performing the first installation step and the connection step, as shown in FIG. 5 (c), on the first surface 21 side of the base material 20 in a state of being stretched by the tensile stress T, in the plane direction with respect to the electronic component 51. The second installation step of providing the reinforcing member 30 so as to be located apart from each other is carried out.

In the second installation step, the reinforcing member 30 is provided so that at least a part of the reinforcing member 30 extends from the position of the first end portion 511 of the electronic component 51 to the position of the second end portion 512.

After carrying out the second installation step, a shrinkage step of removing the tensile stress T from the base material 20 is carried out. As a result, as shown by the arrow C in FIG. 5D, the base material 20 contracts, and the wiring 52 provided on the base material 20 is also deformed.

Here, in the present embodiment, the reinforcing member 30 is provided on the first surface 21 side of the base material 20 so as to extend from at least the position of the first end portion 511 of the electronic component 51 to the position of the second end portion 512. There is.

Therefore, when the tensile stress T is removed from the base material 20, the reinforcing member 30 suppresses its own deformation in the contraction direction so as to resist the contraction of the base material 20, so that the reinforcing member 30 extends. It is possible to suppress the shrinkage of the base material 20 in the expansion / contraction suppressing region A including the region adjacent to the reinforcing member 30 in the direction intersecting the direction in which the electronic component 51 is located.

By suppressing the shrinkage of the base material 20 in the expansion / contraction suppression region A by the reinforcing member 30, the stress acting on the connection portion 51a between the wiring 52 and the electronic component 51 due to the shrinkage of the wiring board 10 can be relaxed. ..

Further, the reinforcing member 30 can relieve the stress acting on the connecting portion 51a as the base material 20 expands and contracts, not only when the wiring board 10 is manufactured but also when the wiring board 10 is used. For example, when a tensile stress acts on the base material 20 when the wiring board 10 is used, the reinforcing member 30 suppresses its own deformation in the stretching direction so as to resist the stretching of the base material 20, and the expansion / contraction suppressing region A By suppressing the elongation of the base material 20 in the above, the stress acting on the connecting portion 51a can be relaxed.

Applications of the wiring board 10 include healthcare field, medical field, nursing care field, electronics field, sports / fitness field, beauty field, mobility field, livestock / pet field, amusement field, fashion / apparel field, security field, and military field. , Distribution field, education field, building materials / furniture / decoration field, environmental energy field, agriculture, forestry and fisheries field, robot field, etc. For example, a product to be attached to a part of the body such as a human arm is configured by using the wiring board 10 according to the present embodiment. Since the wiring board 10 can be extended, for example, by attaching the wiring board 10 to the body in an extended state, the wiring board 10 can be brought into close contact with a part of the body. Therefore, a good wearing feeling can be realized. Further, since it is possible to suppress a decrease in the resistance value of the wiring 52 when the wiring board 10 is extended, it is possible to realize good electrical characteristics of the wiring board 10. In addition, since the wiring board 10 can be extended, it can be installed or incorporated along a curved surface or a three-dimensional shape, not limited to a living body such as a human being. Examples of these products include vital sensors, masks, hearing aids, toothbrushes, adhesive plasters, wetclothes, contact lenses, artificial hands, artificial legs, artificial eyes, catheters, gauze, chemical packs, bandages, disposable bioelectrodes, diapers, home appliances, sportswear. , Wristbands, earmuffs, gloves, swimwear, supporters, balls, rackets, chemical penetration beauty masks, electrical stimulation diet supplies, pocket furnaces, automobile interiors, seats, instrument panels, strollers, drones, wheelchairs, tires, collars, leads, haptics devices , Luncheon mats, hats, clothes, glasses, shoes, insoles, socks, stockings, innerwear, mufflers, earmuffs, bags, accessories, rings, claws, watches, personal ID recognition devices, helmets, packages, IC tags, pets Examples include bottles, stationery, books, carpets, sofas, bedding, lighting, doorknobs, vases, beds, mattresses, cushions, wireless power antennas, batteries, vinyl houses, robot hands, and robot exteriors.

It is possible to make various changes to the above-described embodiment. Hereinafter, a modified example will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described embodiment will be used for the portions that can be configured in the same manner as in the above-described embodiment. Duplicate description is omitted. Further, when it is clear that the action and effect obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(First modification)
First, with reference to FIG. 6, a first modified example in which the wiring 52 has elasticity and does not have the bellows-shaped portion 57 will be described.

1 to 5 (a) to 5 (d) show a stretch suppression region by removing the tensile stress T after providing the wiring 52, the electronic component 51 and the reinforcing member 30 on the base material 20 stretched by the tensile stress T. An example of the wiring board 10 provided with the bellows-shaped portion 57 except for A has been described. In the examples shown in FIGS. 1 to 5 (a) to 5 (d), the reinforcing member 30 suppresses the shrinkage of the base material 20 in the expansion / contraction suppressing region A when the tensile stress T is removed. The stress acting on the connecting portion 51a as the base material 20 shrinks is relaxed.

On the other hand, in the wiring board 10 in the example shown in FIG. 6, the wiring 52 itself has elasticity, and the wiring 52 is not provided with the bellows-shaped portion 57. Since the wiring 52 itself has elasticity, the wiring board 10 can be expanded and contracted without providing the bellows-shaped portion 57. As the material of the wiring 52 having elasticity, the above-mentioned material having elasticity by itself, silver paste, or the like can be used. The wiring 52 may have a linear shape as in FIG. 1 in a plan view, or may have a shape other than the linear shape such as a horseshoe shape.

The wiring board 10 in the example shown in FIG. 6 can be manufactured by providing the wiring 52, the electronic component 51, and the reinforcing member 30 on the first surface 21 side without stretching the base material 20 due to the tensile stress T1.

According to the example shown in FIG. 6, since the step of extending the base material 20 is not required, the man-hours for manufacturing the wiring board 10 can be reduced. Further, since the step of removing the tensile stress T1 of the base material 20 is not required, the shrinkage stress of the base material 20 accompanying the removal of the tensile stress T1 of the base material 20 does not act on the connecting portion 51a.

Further, according to the example shown in FIG. 6, when the reinforcing member 30 exerts a tensile stress on the base material 20 when the wiring board 10 is used, the reinforcing member 30 itself in the stretching direction so as to resist the stretching of the base material 20. By suppressing the deformation, it is possible to suppress the elongation of the base material 20 in the expansion / contraction suppressing region A. As a result, the stress acting on the connecting portion 51a can be relaxed.

(Second modification)
Next, with reference to FIG. 7, a second modified example including a support substrate that supports the wiring 52 will be described.

The wiring board 10 in the example shown in FIG. 7 further includes a support board 40 in addition to the configuration of the wiring board 10 of FIGS. 1 and 2. The support substrate 40 is a plate-shaped member configured to have lower elasticity than the substrate 20. The support substrate 40 is located between the first surface 21 and the wiring 52, and supports the wiring 52. The support substrate 40 includes a second surface 42 located on the base material 20 side and a first surface 41 located on the opposite side of the second surface 42. In the example shown in FIG. 7, the support substrate 40 supports the electronic component 51 and the wiring 52 on the first surface 41 side thereof. Further, the support substrate 40 is joined to the first surface 21 of the base material 20 on the second surface 42 side thereof. For example, an adhesive layer 60 containing an adhesive may be provided between the base material 20 and the support substrate 40. As the material constituting the adhesive layer 60, for example, an acrylic adhesive, a silicone adhesive, or the like can be used. The thickness of the adhesive layer 60 is, for example, 5 μm or more and 200 μm or less. Further, although not shown, the second surface 42 of the support substrate 40 may be bonded to the first surface 21 of the base material 20 by a method in which the non-adhesive surface is molecularly modified and molecularly bonded. In this case, the adhesive layer may not be provided between the base material 20 and the support substrate 40.

The thickness of the support substrate 40 is, for example, 500 nm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. If the thickness of the support substrate 40 is too small, it becomes difficult to handle the support substrate 40 in the process of manufacturing the support substrate 40 and the process of forming a member on the support substrate 40. If the thickness of the support substrate 40 is too large, it becomes difficult to restore the base material 20 at the time of relaxation, and the target base material 20 cannot be expanded or contracted.

As the material constituting the support substrate 40, for example, polyethylene naphthalate, polyimide, polyethylene terephthalate, polycarbonate, acrylic resin and the like can be used. Among them, polyethylene naphthalate or polyimide having good durability and heat resistance can be preferably used.

In the examples shown in FIGS. 5A to 5D, the wiring 52, the electronic component 51, and the reinforcing member 30 are provided on the base material 20 in a state of being stretched by the tensile stress T. On the other hand, according to the second modification, the wiring 52, the electronic component 51, and the reinforcing member 30 are provided on the non-stretched support substrate 40, and then the base material 20 is stretched by the tensile stress T. The wiring board 10 having the bellows-shaped portion 57 can be obtained by joining the support substrate 40 provided with the wiring 52, the electronic component 51, and the reinforcing member 30, and then removing the tensile stress T.

According to the example shown in FIG. 7, since the wiring 52, the electronic component 51, and the reinforcing member 30 can be stably mounted on the support substrate 40 in the non-extended state, the wiring board 10 having the bellows-shaped portion 57 is manufactured. The ease of use can be improved.

(Third modification example)
So far, an example of the wiring board 10 in which the reinforcing member 30 is provided on the wiring 52 or the first surface 21 has been described. On the other hand, as shown in FIGS. 8 and 9, the reinforcing member 30 may be located between the first surface 21 and the wiring 52 or on the first surface 21. In this case, the wiring board 10 may not have the bellows-shaped portion 57 as shown in FIG. 8, or may have the bellows-shaped portion 57 as shown in FIG.

(Fourth modification)
Further, as shown in FIGS. 10 and 11, the reinforcing member 30 may be located in the recess 21a provided on the first surface 21. In this case, the wiring board 10 may not have the bellows-shaped portion 57 as shown in FIG. 10, or may have the bellows-shaped portion 57 as shown in FIG.

(Fifth modification)
Further, as shown in FIGS. 12 and 13, the reinforcing member 30 may be embedded inside the base material 20. In this case, the wiring board 10 may not have the bellows-shaped portion 57 as shown in FIG. 12, or may have the bellows-shaped portion 57 as shown in FIG. In such a base material 20 and the reinforcing member 30, for example, when the base material 20 is produced by pouring resin into a mold and solidifying the resin of the mold, the reinforcing member 30 is placed in the mold at an appropriate timing. Obtained by throwing.

(6th modification)
Further, as shown in FIGS. 14 and 15, the reinforcing member 30 may be located on the second surface 22. In this case, the wiring board 10 may not have the bellows-shaped portion 57 as shown in FIG. 14, or may have the bellows-shaped portion 57 as shown in FIG.

(7th modification)
So far, an example of a wiring board 10 in which the reinforcing member 30 has a circular shape surrounding the entire circumference of the electronic component 51 in a plan view has been described. On the other hand, as shown in FIG. 16, the reinforcing member 30 may have a rectangular shape that surrounds the entire circumference of the electronic component 51 in a plan view.

(8th modification)
Further, as shown in FIG. 17, the reinforcing member 30 may have a shape that partially surrounds the electronic component 51 in a plan view. In the example shown in FIG. 17, the reinforcing member 30 has a substantially rectangular shape in which the portion on the wiring 52 is missing.

(9th variant)
Further, as shown in FIG. 18, the reinforcing member 30 may have a linear shape along the first direction D1 in a plan view.

(10th variant)
So far, an example of a wiring board 10 in which the reinforcing member 30 is continuous from the position of the first end portion 511 of the electronic component 51 to the position of the second end portion 512 of the electronic component 51 has been described. On the other hand, between the position of the first end portion 511 and the position of the second end portion 512 to the extent that the effect of the reinforcing member 30 of relaxing the stress of the connecting portion 51a when the base material 20 is contracted is not impaired. Reinforcing member 30 may be provided discontinuously in the first direction D1.

(11th variant)
So far, an example of a wiring board 10 including an electronic component 51 mounted on the first surface 21 side of the base material 20 has been described. However, the present invention is not limited to this, and the wiring board 10 may not include the electronic component 51. For example, the bellows-shaped portion 57 may be formed on the base material 20 in which the electronic component 51 is not mounted. Further, the support substrate 40 in which the electronic component 51 is not mounted may be bonded to the base material 20. Further, the wiring board 10 may be shipped in a state where the electronic component 51 is not mounted.

(12th variant)
So far, an example in which the bellows-shaped portion 57 is not formed in the expansion / contraction suppressing region A has been described. On the other hand, as shown in FIG. 19, a bellows-shaped portion 57a whose amplitude is attenuated more than that of the bellows-shaped portion 57 outside the expansion / contraction suppression region A may be formed in the expansion / contraction suppression region A.

Next, the present disclosure will be described in more detail with reference to Examples and Comparative Examples, but the present disclosure is not limited to the description of the following Examples as long as the gist is not exceeded.

(Example 1)
As the wiring board 10, a wiring board 10 having a wiring 52 and a reinforcing member 30 provided on the first surface 21 of the base material 20 as shown in FIG. 1 was produced. Hereinafter, a method for manufacturing the wiring board 10 will be described.

A urethane sheet having a thickness of 80 μm was used as the base material 20, and a conductive paste containing a solvent, a binder resin, and silver conductive particles was patterned on the urethane sheet by screen printing. Diethylene glycol monoethyl ether acetate was used as the solvent. Urethane was used as the binder resin. After patterning, annealing treatment was performed in an oven at 80 ° C. for 30 minutes to volatilize the solvent to form the wiring 52. The wiring 52 was configured to be an electrode pair having a thickness of 20 μm, a line width of 200 μm, and an interval of 500 μm. Further, the elastic modulus of the urethane sheet used as the base material 20 was measured by a test based on JIS K6251. As a result, the elastic modulus was 5 Mpa.

Next, the reinforcing member 30 was provided so as to surround the center of the electrode pair. The reinforcing member 30 was coated with JU-120EB manufactured by Kouki Co., Ltd. using a dispenser and cured at 130 ° C. The pattern shape was 1 mm wide and 200 μm thick so as to have a circumferential shape with a radius of 3 mm centered on the electrode pair. Here, the elastic modulus of the reinforcing member 30 was measured by a test based on ASTM D882. As a result, the elastic modulus was 6 Gpa.

Next, an LED chip having a size of 1.0 × 0.5 mm was mounted between the electrode pairs using a conductive adhesive. As the conductive adhesive, CL-3160 manufactured by Kaken Tech Co., Ltd. was used. The wiring board 10 thus formed was pulled in a direction parallel to the wiring and extended by 30%. At this time, the tensile stress applied to the LED connection portion was relaxed by the reinforcing member 30, the conductive connection of the LED chip was maintained, and the LED chip could be lit.

(Example 2)
As the wiring board 10, as shown in FIG. 7, the support substrate 40 was bonded to the first surface 21 of the base material 20, and the wiring 52 and the reinforcing member 30 were provided on the support base material 40. Hereinafter, a method for manufacturing the wiring board 10 will be described.

<Preparation of base material>
An adhesive sheet 8146 (manufactured by 3M) was prepared as an adhesive layer 60 between the support base material 40 and the base material 20. Next, a two-component addition condensation polydimethylsiloxane (hereinafter referred to as PDMS) was applied onto the pressure-sensitive adhesive sheet as the base material 20 so as to have a thickness of about 1 mm, and cured. As a result, a base material 20 with an adhesive layer 60 as shown in FIG. 7 was obtained. In addition, the elastic modulus of PDMS used as the base material 20 was measured by a test based on JIS K6251. As a result, the elastic modulus was 0.05 Mpa.

<Preparation of wiring and reinforcing members>
A 1 μm-thick PEN film that functions as the support substrate 40 was prepared. Subsequently, a copper layer having a thickness of 1 μm was formed on the first surface 41 of the support substrate 40 by a thin-film deposition method. Subsequently, the copper layer was patterned using a photolithography method and an etching method to form the wiring 52. The wiring 52 has a line width of 200 μm and is configured to be a pair of electrodes spaced 500 μm apart. In addition, the elastic modulus of the support substrate 40 was measured by a tensile test based on ASTM D882. As a result, the elastic modulus of the supporting base material 40 was 2.2 Gpa. Next, the reinforcing member 30 and the LED chip were mounted using a conductive adhesive so as to surround the center of the electrode pair as in Example 1.

Subsequently, after the base material 20 with the adhesive layer prepared above is extended by one axis 1.5 times, the surface on which the LED prepared above and the LED of the support base material 40 on which the reinforcing member is installed are not mounted. And the adhesive layer were bonded together. Here, the base material 20 is extended so as to be parallel to the wiring direction. After that, the elongation of the base material 20 was released. As a result, a bellows-shaped portion was formed on the surface of the wiring 52 except for the region surrounded by the reinforcing member 30. After the shrinkage due to the release of the extension of the base material 20, the conductive connection of the LED chip was maintained, and the LED chip could be lit. Further, even when the wiring board 10 thus formed was pulled in the direction parallel to the wiring and extended by 30%, the conductive connection of the LED chip was maintained and the LED chip could be lit. During the contraction and expansion of the base material 20, the stress applied to the LED connection portion was relaxed by the reinforcing member 30, so that the LED chip could be lit.

(Example 3)
As the wiring board 10, as shown in FIG. 17, the support substrate 40 was bonded to the first surface 21 of the base material 20, and the wiring 52 and the reinforcing member 30 were provided on the support base material 40. Hereinafter, a method for manufacturing the wiring board 10 will be described.

The wiring board 10 was produced in the same manner except that the reinforcing member 30 was patterned so as not to overlap the wiring 52 in the second embodiment. In the wiring board 10 formed in this way, a bellows-shaped portion is formed on the surface of the wiring 52 except for the region surrounded by the reinforcing member 30, the wiring board 10 contracts, and the wiring board 10 is in the region surrounded by the reinforcing member 30. Then, a bellows-shaped part having a smaller amplitude than that outside the region was generated. After the shrinkage due to the release of the extension of the base material 20, the conductive connection of the LED chip was maintained, and the LED chip could be lit. Further, even when the wiring board 10 thus formed was pulled in the direction parallel to the wiring and extended by 30%, the conductive connection of the LED chip was maintained and the LED chip could be lit. During the contraction and expansion of the base material 20, the stress applied to the LED connection portion was relaxed by the reinforcing member 30, so that the LED chip could be lit.

(Example 4)
As the wiring board 10, a reinforcing member 30 embedded in the base material 20 as shown in FIG. 11 was produced. Hereinafter, a method for manufacturing the wiring board 10 will be described.

<Preparation of base material>
An adhesive sheet 8146 (manufactured by 3M) was prepared as an adhesive layer between the support base material 40 and the base material 20. Next, a polyimide film (manufactured by Ukosan Co., Ltd .: Upirex thickness 125 μm) was provided as a reinforcing portion 30 on the adhesive sheet. As the pattern shape of the installed reinforcing member 30, one cut with a cutting plotter so as to have a circumferential shape with a width of 1 mm and a radius of 3 mm was used. Next, a two-component addition condensation polydimethylsiloxane (hereinafter referred to as PDMS) was applied onto the pressure-sensitive adhesive sheet as the base material 20 so as to have a thickness of about 1 mm, and cured. As a result, a reinforcing member 30 as shown in FIG. 11 was obtained embedded in the base material 20. Further, the elastic modulus of the polyimide film used as the reinforcing member 30 was measured by a tensile test based on ASTM D882. As a result, the elastic modulus was 7 Gpa.

<Preparation of wiring and reinforcing members>
Wiring and LEDs were arranged on the support base material 40 in the same manner except that the reinforcing member 30 was not arranged in the second embodiment. Next, after the base material 20 in which the reinforcing member 30 prepared above is embedded is extended by one axis 1.5 times, the LED prepared above is placed at the center of the circle of the buried circumferential reinforcing member. The surface of the support base material 40 on which the LED is not mounted and the adhesive layer were bonded so as to be located. After that, the elongation of the base material 20 was released. In the wiring board 10 formed in this way, a bellows-shaped portion is formed on the surface of the wiring 52 except for the region surrounded by the reinforcing member 30, the wiring board 10 contracts, and the wiring board 10 is in the region surrounded by the reinforcing member 30. Then, a bellows-shaped part having a smaller amplitude than that outside the region was generated. After the shrinkage due to the release of the extension of the base material 20, the conductive connection of the LED chip was maintained, and the LED chip could be lit. Further, even when the wiring board 10 thus formed was pulled in the direction parallel to the wiring and extended by 30%, the conductive connection of the LED chip was maintained and the LED chip could be lit. During the contraction and expansion of the base material 20, the stress applied to the LED connection portion was relaxed by the reinforcing member 30, so that the LED chip could be lit.

(Comparative Example 1)
The wiring board 10 was produced in the same manner except that the reinforcing member of the first embodiment was not arranged. The wiring board 10 thus formed was pulled in a direction parallel to the wiring and extended by 30%. At this time, tensile stress was applied to the LED connection portion due to the extension, the conductive connection of the LED chip was disconnected, and the LED was turned off.

(Comparative Example 2)
The wiring board 10 was produced in the same manner except that the reinforcing member of the second embodiment was not arranged. In this case, when the wiring board 10 contracts after the extension of the base material 20 is released, a contraction stress is applied to the LED connection portion due to the contraction, the conduction connection of the LED chip is disconnected, and the LED is turned off. ..

Although some modifications to the above-described embodiments have been described, it is naturally possible to apply a plurality of modifications in combination as appropriate.

10 Wiring board 20 Base material 21 First surface 22 Second surface 30 Reinforcing member 40 Support substrate 51 Electronic component 52 Wiring 53 Mountain part 54 Mountain part 55 Valley part 56 Valley part 57 Bellows-shaped part

Claims (14)

It's a wiring board
A base material having a first surface and a second surface opposite to the first surface and having elasticity in at least one of the surface directions along the first surface and the second surface.
Wiring located on the first surface side and connected to at least one electronic component mounted on the wiring board, and
A reinforcing member, which is located away from the electronic component in the plane direction and reinforces the base material, is provided.
At least a part of the reinforcing member extends from the position of the first end portion of the electronic component in the first direction to the position of the second end portion facing the first end portion in the first direction. Wiring board. The wiring board according to claim 1, wherein the reinforcing member has a shape surrounding the electronic component when viewed from the normal direction of the first surface. The wiring board according to claim 2, wherein the reinforcing member has a shape that surrounds the entire circumference of the electronic component when viewed from the normal direction. The wiring board according to claim 2, wherein the reinforcing member has a shape that partially surrounds the electronic component when viewed from the normal direction. The wiring board according to any one of claims 1 to 4, wherein the reinforcing member has a flexural rigidity larger than the flexural rigidity of the base material. The wiring board according to any one of claims 1 to 5, wherein the reinforcing member has an elastic modulus larger than that of the base material. The wiring board according to any one of claims 1 to 6, wherein the reinforcing member is located on the wiring or on the first surface. The wiring board according to any one of claims 1 to 6, wherein the reinforcing member is located between the first surface and the wiring or on the first surface. The wiring board according to any one of claims 1 to 6, wherein the reinforcing member is embedded inside the base material. The wiring board according to any one of claims 1 to 6, wherein the reinforcing member is located on the second surface. The wiring board according to any one of claims 1 to 10, wherein the wiring has a longitudinal direction along the first direction. The wiring board according to claim 11, wherein the wiring has a bellows-shaped portion including a plurality of peaks and valleys arranged along the longitudinal direction. The wiring board according to any one of claims 1 to 12, further comprising a support board which is located between the first surface and the wiring and supports the wiring. It is a method of manufacturing a wiring board.
The first surface is formed on a base material having a first surface and a second surface opposite to the first surface and having elasticity in at least the first direction among the surface directions along the first surface and the second surface. An extension step of applying tensile stress in one direction to extend the base material, and
A first installation step of providing wiring connected to at least one electronic component mounted on the wiring board on the first surface side of the stretched base material.
A second installation step of providing a reinforcing member for reinforcing the base material so as to be located away from the electronic component in the plane direction is provided.
In the second installation step, the position of the second end portion where at least a part of the reinforcing member faces the first end portion in the first direction from the position of the first end portion of the electronic component in the first direction. A method of manufacturing a wiring board, which comprises providing the reinforcing member so as to extend at least to.