JP7672099B2 - Conductor-equipped laminate, sheet heater, optical sensor, and conductor-equipped resin material - Google Patents

Description

This disclosure generally relates to a laminate with a conductor, a planar heater, an optical sensor, and a resin material with a conductor, and more specifically, this disclosure relates to a laminate with a conductor comprising a resin layer, a conductor, and an insulating substrate, a planar heater comprising this laminate with a conductor, an optical sensor comprising this planar heater, and a resin material with a conductor comprising a resin layer and a conductor.

Conventionally, wiring boards in which metal conductor wiring is formed on the surface of an insulating substrate have been widely used.

In the invention described in Patent Document 1, copper foil is adhered to one side of a heat-resistant insulating film via an adhesive layer, and a metal film is deposited on the other side by a deposition method or the like to obtain a functional copper-clad laminate that can be used as a material for printed wiring boards.

Japanese Utility Model Application Publication No. 7-26126

The objective of the present disclosure is to provide a laminate with a conductor in which damage to the conductor wiring due to deformation is unlikely to occur, a planar heater including the laminate with a conductor, an optical sensor including the planar heater, and a resin material with a conductor that can be used to produce the laminate with a conductor.

A laminate with a conductor according to an embodiment of the present disclosure includes a resin material with a conductor, the resin material including a resin layer containing a resin (A) having a glass transition temperature of 40° C. or less and a conductor wiring having a volume resistivity of 10 μΩcm or less at 25° C., and an insulating substrate. At least a part of the conductor wiring is embedded in the resin layer. The insulating substrate overlaps the resin material with a conductor. The area of a cross section perpendicular to the longitudinal direction of the conductor wiring is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less. The conductor wiring has an exposed surface exposed from the resin layer at a surface of the resin material with a conductor facing the insulating substrate, and the exposed surface is in direct contact with the insulating substrate. The peel strength between the conductor wiring and the insulating substrate is less than 0.01 N/25 mm.

A laminate with a conductor according to another embodiment of the present disclosure comprises a resin material with a conductor, the resin material comprising a resin layer containing a resin (A) having a glass transition temperature of 40° C. or less and a conductor wiring having a volume resistivity of 10 μΩcm or less at 25° C., and an insulating substrate. At least a portion of the conductor wiring is embedded in the resin layer. The insulating substrate overlaps the resin material with a conductor. The area of a cross section perpendicular to the longitudinal direction of the conductor wiring is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less. A portion of the resin layer is interposed between the conductor wiring and the insulating substrate.

A planar heater according to one aspect of the present disclosure includes any of the conductor-equipped laminates described above.

The optical sensor according to one aspect of the present disclosure includes the planar heater and a light receiving unit that receives light transmitted through the planar heater.

A resin material with a conductor according to one embodiment of the present disclosure includes a resin layer and a conductor wiring. At least a portion of the conductor wiring is embedded in the resin layer. The resin layer has a first surface facing in the thickness direction of the resin layer and a second surface facing in the opposite direction to the first surface. The conductor wiring is not exposed to either the first surface or the second surface.

In a conductor-equipped laminate according to one aspect of the present disclosure, breakage of the conductor wiring due to deformation is unlikely to occur.

FIG. 1 is a schematic cross-sectional view of a laminate with a conductor produced by a conventional technique. 2A, 2B, and 2C are schematic cross-sectional views showing an example of a conductor-attached laminate according to an embodiment of the present disclosure. FIG. 3A is a schematic cross-sectional view of an optical sensor according to one embodiment of the present disclosure, and FIG. 3B is a perspective view of a portion of an automobile including the optical sensor.

This article provides an overview of how the inventors came to complete this disclosure.

When an optical sensor 3 such as LiDAR used for an autonomous driving system or the like is installed on an automobile near the emblem or headlights of the vehicle body, if snow adheres to light-transmitting parts such as the outer surface of the emblem or the windshield of the headlights, the light transmission is hindered and detection accuracy is reduced. For this reason, the inventors considered installing a sheet heater 2 equipped with conductor wiring 12 on the light-transmitting parts of the outer surface of the vehicle body.

If a wiring board with conductor wiring 12 provided on an insulating substrate 13 is directly applied to a sheet heater 2, the conductor wiring 12 will be exposed and prone to damage. Also, when the sheet heater 2 is bent or stretched to conform to the shape of an external surface such as an emblem or windshield, the conductor wiring 12 will be subjected to force and will easily break.

The inventors have also considered constructing a sheet heater 2 by embedding conductor wiring 12 on one side of a resin layer 11, as shown in Figure 1, and bonding an insulating substrate 13 with an adhesive to the surface of the resin layer 11 where the conductor wiring 12 is exposed. However, even in this case, deformation of the sheet heater 2 is likely to cause breakage.

Therefore, the inventors conducted intensive research and development to provide a conductor-attached laminate 1 in which the conductor wiring 12 is less likely to be damaged due to deformation, and as a result, they have completed the present disclosure.

Although this disclosure was completed through the above process, the use of the conductor-equipped laminate 1 is not limited to the planar heater 2, and it may be used, for example, as a wiring board that does not function as a heater.

(1) Overview One embodiment of the present disclosure will be described below.

A conductor-attached laminate 1 according to an embodiment of the present disclosure includes a conductor-attached resin material 4 including a resin layer 11 containing a resin (A) having a glass transition temperature of 40° C. or less and a conductor wiring 12 having a volume resistivity of 10 μΩcm or less at 25° C., and an insulating substrate 13. At least a portion of the conductor wiring 12 is embedded in the resin layer 11. The insulating substrate 13 overlaps the conductor-attached resin material 4. The area of a cross section perpendicular to the longitudinal direction of the conductor wiring 12 is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less. The peel strength between the conductor wiring 12 and the insulating substrate 13 is less than 0.01 N/25 mm.

The longitudinal direction of the conductor wiring 12 is the direction in which the conductor wiring 12 extends when viewed in the direction in which the insulating substrate 13 and the conductor-equipped resin material 4 overlap, and can also be said to be the direction in which current flows through the conductor wiring 12 when energized (current flow direction).

The peel strength between the conductor wiring 12 and the insulating substrate 13 is measured using a sample of a laminate 1 with a conductor, in which a resin layer 11 with a width of 25 mm in plan view, a conductor wiring 12 with a width of 25 mm in plan view, and an insulating substrate 13 with a width of 25 mm in plan view are laminated in this order, in accordance with JIS Z0237 "Test methods for adhesive tapes and adhesive sheets." This peel strength is preferably less than 0.001 N/25 mm, and more preferably 0 N/25 mm.

As shown in FIG. 1, if the surface of the conductor wiring 12 exposed from the resin layer 11 and the insulating substrate 13 are fixed with an adhesive layer 14, the stress generated by the deformation of the conductor-equipped laminate 1 tends to concentrate at the interface between the conductor wiring 12 and the adhesive layer 14, making the conductor wiring 12 prone to breakage.

However, in this embodiment, as described above, the peel strength between the conductor wiring 12 and the insulating substrate 13 is less than 0.01 N/25 mm, so even if the conductor-equipped laminate 1 is deformed, the above-mentioned concentration of stress in the conductor wiring 12 is unlikely to occur. Therefore, in this embodiment, a conductor-equipped laminate 1 can be obtained in which the conductor wiring 12 is unlikely to be damaged due to deformation.

A conductor-attached laminate 1 according to another embodiment of the present disclosure comprises a conductor-attached resin material 4 including a resin layer 11 containing a resin (A) having a glass transition temperature of 40° C. or less and a conductor wiring 12 having a volume resistivity of 10 μΩcm or less at 25° C., and an insulating substrate 13. At least a portion of the conductor wiring 12 in the conductor-attached resin material 4 is embedded in the resin layer 11. The insulating substrate 13 overlaps the conductor-attached resin material 4. The area of a cross section perpendicular to the longitudinal direction of the conductor wiring 12 is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less. A portion of the resin layer 11 is interposed between the conductor wiring 12 and the insulating substrate 13.

As shown in FIG. 1, if the surface of the conductor wiring 12 exposed from the resin layer 11 and the insulating substrate 13 are fixed with an adhesive layer 14, the stress generated by the deformation of the conductor-equipped laminate 1 tends to concentrate at the interface between the conductor wiring 12 and the adhesive layer 14, making the conductor wiring 12 prone to breakage.

However, in this embodiment, as described above, at least a portion of the conductor wiring 12 is embedded in the resin layer 11, and a portion of the resin layer 11 is interposed between the conductor wiring 12 and the insulating substrate 13. Therefore, even if the conductor-equipped laminate 1 is deformed, the above-mentioned concentration of stress in the conductor wiring 12 is unlikely to occur. Therefore, in this embodiment, it is possible to obtain a conductor-equipped laminate 1 in which the conductor wiring 12 is unlikely to be damaged due to deformation.

(2) Details of Laminate with Conductor A more specific structure of the laminate with conductor 1 according to this embodiment will be described with reference to Figs. 2A, 2B, and 2C.

(2.1) First embodiment FIG. 2A shows a conductor-equipped laminate 1 according to a first embodiment.

The conductor-attached laminate 1 according to the first embodiment comprises a conductor-attached resin material 4 and an insulating substrate 13. The conductor-attached resin material 4 comprises a resin layer 11 and a conductor wiring 12, with a portion of the conductor wiring 12 embedded in the resin layer 11. The conductor wiring 12 has an exposed surface 12a that is exposed from the resin layer 11 on the surface of the conductor-attached resin material 4 that faces the insulating substrate 13, and the exposed surface 12a is in direct contact with the insulating substrate 13.

The resin layer 11 is, for example, plate-like or sheet-like. The resin layer 11 has a thickness and has a first surface 1a facing in the thickness direction and a second surface 1b facing in the opposite direction to the first surface 1a. The conductor wiring 12 has an exposed surface 12a. The conductor wiring 12 is embedded in the resin layer 11 except for the exposed surface 12a, and the exposed surface 12a is exposed to the outside of the resin layer 11 at the first surface 1a. The exposed surface 12a and the first surface 1a are on the same plane.

The insulating substrate 13 is, for example, sheet-like or plate-like. The first surface 1a and exposed surface 12a of the resin material 4 with conductor overlap the insulating substrate 13, and in this state, the insulating substrate 13 and the resin material 4 with conductor are bonded together. The first surface 1a is bonded to the insulating substrate 13, and the exposed surface 12a is in contact with the insulating substrate 13, but the peel strength between the conductor wiring 12 and the insulating substrate 13 is less than 0.01 N/25 mm. The first surface 1a and the insulating substrate 13 may be bonded together via an adhesive, or the first surface 1a may be fused to the insulating substrate 13.

The resin layer 11 is made of resin (A). The resin (A) is, for example, a thermoplastic resin. In this case, the resin layer 11 can be heat-sealed to an object such as a vehicle body. The resin layer 11 may contain only the resin (A). The resin layer 11 may further contain a material other than the resin (A), such as an inorganic filler.

It is preferable that the resin layer 11 contains a resin (A) having a glass transition temperature of 40°C or lower. By containing a resin (A) having a glass transition temperature of 40°C or lower, the resin layer 11 is likely to have flexibility. By having flexibility, the resin layer 11 is easily deformed, and the stress associated with the deformation is unlikely to be concentrated on the conductor wiring 12.

The storage modulus of the resin layer 11 at 25° C. is preferably 10 ⁴ MPa or more and less than 10 ⁹ MPa. When the storage modulus of the resin layer 11 at 25° C. is 10 ⁴ MPa or more, it is possible for the resin layer 11 to maintain its shape. When the storage modulus of the resin layer 11 at 25° C. is less than 10 ⁹ MPa, stress is less likely to concentrate on the conductor wiring 12 when the resin layer 11 is deformed, and the conductor wiring 12 is less likely to be damaged. The storage modulus of the resin layer 11 at 25° C. is more preferably 10 ⁵ MPa or more and 10 ⁸ MPa or less.

The resin (A) contains, for example, at least one of an acrylic resin and a thermoplastic elastomer. This makes it easier to achieve the above-mentioned glass transition temperature of the resin (A) and the above-mentioned storage modulus of the resin layer 11. The acrylic resin is a polymer of at least one monomer selected from the group consisting of, for example, butyl acrylate and methyl methacrylate. In this case, the above-mentioned glass transition temperature and storage modulus can be adjusted by adjusting the type and ratio of the monomer. The thermoplastic elastomer contains, for example, at least one selected from the group consisting of an olefin-based thermoplastic elastomer and a polybutadiene-based thermoplastic elastomer. Note that the components that can be contained in the resin (A) are not limited to the above.

The thickness of the resin layer 11 is preferably 25 μm or more and 200 μm or less, and more preferably 50 μm or more and 150 μm or less. When the thickness of the resin layer 11 is 25 μm or more, it is easy to form the resin material 4 with a conductor. When the thickness of the resin layer 11 is 200 μm or less, it is easy to make the laminate 1 with a conductor thin.

It is preferable that the resin layer 11 is transparent. In particular, it is preferable that the total light transmittance in the thickness direction of the resin layer 11 measured according to JIS K7361 is 80% or more, and the haze value in the thickness direction of the resin layer 11 measured according to JIS K7136 is 2% or less.

The conductor wiring 12 is made of a metal such as copper. There is no particular restriction on the shape of the conductor wiring 12. The conductor wiring 12 can be used, for example, as a heating wire. The conductor wiring 12 may also be used to transmit electric current. The conductor wiring 12 is, for example, lattice-shaped, mesh-shaped, fan-shaped, or meander-shaped. In this case, the conductor wiring 12 can be easily spread out into a plane, and therefore the conductor-equipped laminate 1 can be easily applied to a plane heater. It is particularly preferable that the conductor wiring 12 is meander-shaped. In this case, even if the conductor-equipped laminate 1 is deformed, the conductor wiring 12 is particularly unlikely to be damaged.

It is preferable that the volume resistivity of the conductor wiring 12 at 25°C is 10 μΩcm or less, and the area of the cross section perpendicular to the longitudinal direction of the conductor wiring 12 is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less. If the volume resistivity is 10 μΩcm or less, the amount of heat generated by the conductor wiring 12 when electricity is applied is easily increased, and therefore the conductor wiring 12 can easily generate heat even if the width of the conductor wiring 12 is reduced. Therefore, the heat generation property of the conductor wiring 12 is easily maintained while making the conductor wiring 12 difficult to be visually recognized, and the conductor-attached laminate 1 can be easily applied to a planar heater provided on the rear window of an automobile, for example. Furthermore, if the cross-sectional area of the conductor wiring 12 is 0.2×10 ³ μm ² or more, the conductor wiring 12 easily generates heat when electricity is applied. Furthermore, if the cross-sectional area is 10×10 ³ μm ² or less, the conductor wiring 12 is less likely to interfere with the transmission of light through the conductor-attached laminate 1, and the influence of the conductor wiring 12 on the sensing of the optical sensor can be reduced. The volume resistivity is more preferably 6 μΩcm or less, and even more preferably 3 μΩcm or less. The volume resistivity is, for example, 1 μΩcm or more, but is not limited thereto. The cross-sectional area of the conductor wiring 12 is more preferably 0.5×10 ³ μm ² or more, and even more preferably 1.0×10 ³ μm ² or more. The cross-sectional area is more preferably 7.5×10 ³ μm ² or less, and even more preferably 5.0×10 ³ μm ² or less.

A method for producing the resin material 4 with a conductor will be described. For example, a molding material containing a resin (A) is molded by an appropriate method to produce a sheet-like or plate-like molded body, and the conductor wiring 12 is embedded in this molded body by an appropriate method. As a result, a resin layer 11 is produced from the molded body, and a resin material 4 with a conductor including the conductor wiring 12 and the resin layer 11 can be obtained. More specifically, for example, the molding material is first molded by an appropriate method such as an extrusion molding method, a solution casting method, or a calendar method to produce a molded body. Next, the conductor wiring 12 is formed on the surface of the molded body by an appropriate method such as an additive method or a subtractive method. Next, the molded body and the conductor wiring 12 are heat-pressed to embed the conductor wiring 12 in the molded body while deforming the molded body. As a result, a resin layer 11 is produced from the molded body, and the conductor wiring 12 can be embedded in the resin layer 11 so that the exposed surface 12a is exposed on the first surface 1a of the resin layer 11.

The method of producing the resin material 4 with a conductor is not limited to the above. For example, the resin material 4 with a conductor may be produced by insert molding. In this case, for example, the conductor wiring 12 is placed in the mold, and a molding material containing resin (A) is molded in the mold to obtain the resin material 4 with a conductor. Alternatively, the surface of the film may be subjected to an appropriate release treatment, and then the conductor wiring 12 may be produced on the surface of the film, and a flexible resin material may be placed on the surface of the film with the conductor wiring 12 to embed the conductor wiring 12 in the resin material, and then the film may be peeled off from the resin material and the conductor wiring 12. In this case, the resin layer 11 is produced from the resin material, and the conductor wiring 12 is embedded in the resin layer 11.

The insulating substrate 13 is made of resin (B). The insulating substrate 13 may contain only resin (B). The insulating substrate 13 may also contain materials other than resin (B), such as inorganic fillers and reinforcing materials.

It is preferable that the insulating substrate 13 contains a resin (B) having a glass transition temperature of 80°C or higher. When the glass transition temperature of the insulating substrate 13 is 80°C or higher, sufficient strength is obtained to protect the conductor wiring 12.

Resin (B) contains at least one selected from the group consisting of, for example, polycarbonate, polyethylene terephthalate, and polymethyl methacrylate. Note that the components contained in resin (B) are not limited to these.

It is preferable that the insulating substrate 13 is transparent. It is preferable that the total light transmittance in the thickness direction of the insulating substrate 13 measured according to JIS K7361 is 80% or more, and the haze value in the thickness direction of the resin layer 11 measured according to JIS K7136 is 2% or less.

The thickness of the insulating substrate 13 is preferably 50 μm or more and 500 μm or less. When the thickness of the insulating substrate 13 is within this range, it is easy to make the conductor-equipped laminate 1 thin.

It is preferable that the water contact angle θ of the surface of the insulating substrate 13 is 60° or more. When the water contact angle θ of the surface of the insulating substrate 13 is 60° or more, water is less likely to adhere to the surface of the insulating substrate 13, and particularly when the conductor-attached laminate 1 is used as a planar heater 2 for melting snow, water generated by melting snow is more likely to flow off the surface of the conductor-attached laminate 1. It is more preferable that the water contact angle θ of the insulating substrate 13 is 90° or more. In order to set the water contact angle θ of the surface of the insulating substrate 13 within the above range, a hydrophobic resin may be selected as the resin (B), or the insulating substrate 13 may contain a hydrophobic material. The surface of the insulating substrate 13 may be subjected to a water-repellent treatment.

The surface of the insulating substrate 13 may be subjected to a surface treatment as described above. Specific examples of surface treatment include water repellent treatment and hard coat treatment.

The insulating substrate 13 can be produced, for example, by molding a molding material containing resin (B) using an appropriate method such as extrusion molding, injection molding, solution casting, or calendaring.

The laminate 1 with conductor is produced, for example, by stacking an insulating substrate 13 on a resin material 4 with conductor and bonding the resin layer 11 in the resin material 4 with conductor to the insulating substrate 13. If the resin layer 11 contains a thermoplastic resin, the resin layer 11 and the insulating substrate 13 can be bonded by heat pressing.

In this embodiment, the exposed surface 12a of the conductor wiring 12 is in contact with the insulating substrate 13 without being bonded, and the portion of the conductor wiring 12 other than the exposed surface 12a is embedded in the resin layer 11. Therefore, even if the conductor-equipped laminate 1 is deformed, it is difficult for the insulating substrate 13 to apply force to the conductor wiring 12. Therefore, stress is unlikely to concentrate at the interface between the conductor wiring 12 and the insulating substrate 13.

The thickness of the conductor-attached laminate 1 is preferably 75 μm or more and 550 μm or less. By making the thickness of the conductor-attached laminate 1 75 μm or more, the strength of the conductor-attached laminate 1 can be maintained. Furthermore, by making the thickness 550 μm or less, the conductor-attached laminate 1 can be made thinner. This thickness is more preferably 150 μm or more, and even more preferably 250 μm or more. Furthermore, this thickness is more preferably 400 μm or less, and even more preferably 350 μm or less.

When a tensile load is applied to the resin material 4 with conductor in at least one direction perpendicular to the thickness direction of the resin layer 11 in at least one temperature atmosphere between -20°C and 50°C, the elongation rate of the resin material 4 with conductor at which the conductor wiring 12 breaks (hereinafter referred to as the conductor elongation rate) is preferably 110% or more. In this case, even if the resin material 4 with conductor is deformed, the conductor wiring 12 is particularly unlikely to break. The resin material 4 with conductor according to this embodiment has the above-mentioned configuration and is therefore capable of having such a conductor elongation rate. It is even more preferable if the conductor elongation rate is 120% or more.

It is more preferable that the resin material 4 with conductor has the above conductor elongation rate in a temperature atmosphere of 25°C. It is also more preferable that the resin material 4 with conductor has the above conductor elongation rate in at least one of temperature atmospheres of -20°C and 50°C. It is particularly preferable that the resin material 4 with conductor has the above conductor elongation rate in any temperature atmosphere between -20°C and 50°C. It is also particularly preferable that the resin material 4 with conductor has the above conductor elongation rate even when a tensile load is applied to the resin material 4 with conductor in any direction perpendicular to the thickness direction of the resin layer 11.

It is preferable that the conductor-attached laminate 1 has a total light transmittance in the thickness direction of 80% or more as measured based on JIS K7361, and a haze value in the thickness direction of 2% or less as measured based on JIS K7136. If the total light transmittance is 80% or more and the haze value is 2% or less, the conductor-attached laminate 1 is suitable as a material for the planar heater 2 attached to the optical sensor 3.

(2.2) Second embodiment FIG. 2B shows a conductor-equipped laminate 1 according to a second embodiment.

The conductor-attached laminate 1 according to the second embodiment differs from the conductor-attached laminate 1 according to the first embodiment in that a portion of the resin layer 11 is interposed between the conductor wiring 12 and the insulating substrate 13. The rest of the configuration is the same as that of the conductor-attached laminate 1 according to the first embodiment. Hereinafter, the explanation of the configuration that overlaps with the first embodiment will be omitted as appropriate by assigning the same reference numerals.

In the second embodiment, as in the first embodiment, the conductor-attached laminate 1 includes a conductor-attached resin material 4 and an insulating substrate 13, but as described above, a part of the resin layer 11 is interposed between the conductor wiring 12 and the insulating substrate 13. As a result, the conductor wiring 12 and the insulating substrate 13 are not bonded to each other, nor are they in direct contact with each other. Therefore, even if the conductor-attached laminate 1 is deformed, stress is unlikely to concentrate on the conductor wiring 12. Therefore, in the conductor-attached laminate 1 obtained from the conductor-attached resin material 4 according to the second embodiment, the conductor wiring 12 is unlikely to be damaged even if it is deformed.

The conductor-attached resin material 4 in the second embodiment will be described. The conductor-attached resin material 4 includes a resin layer 11 and conductor wiring 12. The resin layer 11 has a first surface 1a facing in its thickness direction and a second surface 1b facing in the opposite direction to the first surface 1a. The conductor wiring 12 is embedded in the resin layer 11, and the conductor wiring 12 is not exposed on either the first surface 1a or the second surface 1b. Other than this, the conductor-attached resin material 4 has the same configuration as in the first embodiment.

The insulating substrate 13 has the same configuration as in the first embodiment.

The first surface 1a of the resin layer 11 in the conductor-attached resin material 4 is superimposed on and bonded to the insulating substrate 13. The first surface 1a and the insulating substrate 13 may be bonded via an adhesive, or the first surface 1a may be fused to the insulating substrate 13. Therefore, between the conductor wiring 12 and the insulating substrate 13, there is a portion between the first surface 1a of the resin layer 11 and the conductor wiring 12.

A method for producing the resin material 4 with a conductor will be described. For example, a molding material containing a resin (A) is molded by an appropriate method to produce a sheet-like or plate-like molded body, and the conductor wiring 12 is embedded in this molded body by an appropriate method. As a result, a resin layer 11 is produced from the molded body, and a resin material 4 with a conductor having the conductor wiring 12 and the resin layer 11 can be obtained. More specifically, for example, the molding material is first molded by an appropriate method such as an extrusion molding method, a solution casting method, or a calendar method to produce two molded bodies (a first molded body and a second molded body). Next, the conductor wiring 12 is formed on the surface of the first molded body by an appropriate method such as an additive method or a subtractive method. Next, the first molded body and the second molded body are laminated so that the conductor wiring 12 is interposed between them, and then heat pressed, and the conductor wiring 12 is embedded between the first molded body and the second molded body while deforming the first molded body and the second molded body. This allows a resin layer 11 to be produced from the first molded body and the second molded body, and allows the conductor wiring 12 to be embedded in the resin layer 11 so that it is not exposed on either the first surface 1a or the second surface 1b of the resin layer 11.

The method of producing the resin material 4 with a conductor is not limited to the above. For example, the resin material 4 with a conductor may be produced by insert molding. In this case, for example, the conductor wiring 12 is placed in the mold, and a molding material containing resin (A) is molded in the mold to obtain the resin material 4 with a conductor. Alternatively, the surface of the film may be subjected to an appropriate release treatment, and then the conductor wiring 12 may be produced on the surface of the film, and a flexible resin material may be placed on the surface of the film with the conductor wiring 12 to embed the conductor wiring 12 in the resin material, and then the film may be peeled off from the resin material and the conductor wiring 12. In this case, the resin layer 11 is produced from the resin material, and the conductor wiring 12 is embedded in the resin layer 11.

The thickness of the resin material 4 with conductor is preferably 50 μm or more and 200 μm or less. When the thickness is 50 μm or more, the conductor wiring 12 can be stably arranged in the resin layer 11. Furthermore, when the thickness is 200 μm or less, the resin material 4 with conductor can be made thin. This thickness is more preferably 75 μm or more, and even more preferably 100 μm or more. Furthermore, this thickness is more preferably 175 μm or less, and even more preferably 150 μm or less.

When light from a D65 light source is incident on the conductor-attached resin material 4 in the thickness direction, it is preferable that the total light transmittance is 80% or more and the haze value is 2% or less.

It is preferable that the conductor-attached resin material 4 according to this embodiment has a conductor elongation rate similar to that of the first embodiment.

(2.3) Third embodiment FIG. 2C shows a conductor-equipped laminate 1 according to a third embodiment.

The conductor-attached laminate 1 according to the third embodiment differs from the conductor-attached laminate 1 according to the first embodiment in that the second surface 1b of the conductor-attached resin material 4 overlaps the insulating substrate 13, and the insulating substrate 13 and the conductor-attached resin material 4 are bonded in this state. The rest of the configuration is the same as that of the conductor-attached laminate 1 according to the first embodiment. Below, explanations of the configuration that overlaps with the first embodiment will be omitted as appropriate.

In the third embodiment, as in the first embodiment, the conductor-attached laminate 1 includes a conductor-attached resin material 4 and an insulating substrate 13, but as described above, the second surface 1b of the conductor-attached resin material 4 overlaps the insulating substrate 13, and in this state, the insulating substrate 13 and the conductor-attached resin material 4 are bonded together. As a result, a part of the resin layer 11 is interposed between the conductor wiring 12 and the insulating substrate 13, and the conductor wiring 12 and the insulating substrate 13 are not bonded together, nor are they in direct contact with each other. Therefore, even if the conductor-attached laminate 1 is deformed, stress is unlikely to concentrate on the conductor wiring 12. Therefore, even if the conductor-attached laminate 1 obtained from the conductor-attached resin material 4 according to the third embodiment is deformed, the conductor wiring 12 is unlikely to be damaged.

The resin material 4 with conductor in the third embodiment has the same configuration as that in the first embodiment, and the manufacturing method is also the same as that in the first embodiment. It is preferable that the resin material 4 with conductor in this embodiment has a conductor elongation rate similar to that in the first embodiment.

The insulating substrate 13 also has the same configuration as in the first embodiment.

(3) Planar heater As described above, the conductor-equipped laminate 1 can be applied to a planar heater 2. This planar heater 2 includes the conductor-equipped laminate 1. It is preferable that this planar heater 2 further includes a terminal connection portion. The terminal connection portion may be integrated with the conductor-equipped laminate 1, or may have a structure that protrudes from an end portion of the conductor-equipped laminate 1. The planar heater 2 is connected to a power source via the terminal connection portion, and can be used as a heater when the conductor wiring 12 generates heat due to electricity supplied from the power source.

Since the conductor-equipped laminate 1 has the above-mentioned configuration, this planar heater 2 is less likely to break even when the conductor-equipped laminate 1 is bent or stretched. Therefore, this planar heater 2 can be attached to the curved outer surface of an automobile part, for example, by bending or stretching it, and can be used as a snow melting heater. Note that the uses of the planar heater 2 are not limited to only as a snow melting heater for automobile parts.

(4) Optical Sensor The optical sensor 3 will now be described. The optical sensor 3 includes the above-mentioned sheet heater 2 and a light receiving unit 15 that receives light transmitted through the sheet heater 2 (see FIG. 3). The optical sensor 3 is provided on the body of an automobile, on an emblem, near a headlight, etc., for an automatic driving system, etc. By including the sheet heater 2, the optical sensor 3 is less likely to have snow adhere to the portion through which light transmits. Therefore, the optical sensor 3 is likely to operate well even during snowfall.

Figure 3A shows a specific example of the optical sensor 3. In addition to the planar heater 2 and the light receiving unit 15, this optical sensor 3 includes a light projecting unit 16 that irradiates light toward the planar heater 2.

Specifically, the optical sensor 3 shown in FIG. 3A includes a housing 18, a light receiving unit 15, a light projecting unit 16, and a beam splitter 17 arranged in the housing 18, and a planar heater 2. The housing 18 has an exposed surface 31 exposed to the outdoors. A part of the housing 18 is a light transmitting unit 20 that can transmit light, and the light transmitting unit 20 constitutes at least a part of the exposed surface 31. Through the light transmitting unit 20, light can be emitted from the inside of the housing 18 to the outside, and can enter from the outside to the inside. The light transmitting unit 20 is made of, for example, silicate glass, transparent resin, etc. The light receiving unit 15 is an element that can detect light by receiving light, such as a light receiving element, that is, an element that converts the intensity of light into an electrical signal. The light projecting unit 16 is an element that can emit light, such as a laser emitter. The light receiving unit 15, the light projecting unit 16, and the beam splitter 17 are arranged so that the beam splitter 17 controls the direction of the light emitted by the light projecting unit 16 so that it is directed toward the transmission unit 20, and so that the beam splitter 17 controls the direction of the light that is incident from the outside to the inside of the housing 18 through the transmission unit 20 so that it is directed toward the light receiving unit 15. The arrows in FIG. 3A indicate the paths of the light mentioned above.

The planar heater 2 is disposed on the exposed surface 31 of the housing 18 and covers the transmissive portion 20. The conductor-attached laminate 1 is disposed so that the conductor-attached resin material 4 is located between the insulating substrate 13 and the transmissive portion 20. Therefore, the insulating substrate 13 can protect the conductor-attached resin material 4 by covering it.

In this optical sensor 3, when the light-emitting unit 16 emits light, the direction of the light is controlled by the beam splitter 17 so that the light is directed toward the transparent unit 20. The light passes through the transparent unit 20 and the planar heater 2 and is emitted to the outside of the housing 18. When this light is reflected by the object and directed toward the optical sensor 3, it passes through the planar heater 2 and the transparent unit 20 and enters the inside of the housing 18. The direction of this light is controlled by the beam splitter so that the light is directed toward the light-receiving unit 15. The light-receiving unit 15 receives the light and can detect it. This detection result can be used, for example, to measure the distance between the optical sensor 3 and the object.

Even if snow adheres to the outer surface (exposed surface 31) of this optical sensor 3, the planar heater 2 can generate heat on the surface of the planar heater 2 to melt the snow. This makes it difficult for the snow to impede the progression of light, and the detection accuracy of the optical sensor 3 is less likely to decrease.

This optical sensor 3 is suitable for use outdoors. For example, as shown in FIG. 3B, the optical sensor 3 can be attached to the body of the automobile 21 with the exposed surface 31 facing the outside of the body. In this case, the optical sensor 3 can be used as a component of a distance measuring device for measuring the distance between the automobile 21 and an object in an autonomous driving system, for example. Using this optical sensor 3 can prevent the accuracy of the measurement results by the distance measuring device from decreasing during snowfall, thereby improving the stability of the autonomous driving system.

The present disclosure will be specifically explained below using examples. However, the present disclosure is not limited to the examples.

[Raw materials for resin (A)]
As the resin (A) in each of the examples and comparative examples, an acrylic resin obtained by polymerizing butyl acrylate (glass transition temperature -55°C) and methyl methacrylate (glass transition temperature 105°C) in the ratio shown in the "Resin layer" column in Table 1 was prepared.

[Formation of resin layer 11]
The above resin (A) was molded by injection molding to form a resin layer 11 having a thickness shown in the "Resin layer" column of Table 1.

[Formation of Conductor Wiring 12]
A copper foil (thickness 12 μm) which is the material of the conductor wiring 12 was laminated on the surface of the resin layer 11, and the laminate was hot-pressed at a heating temperature of 250° C., a pressure of 1 MPa, and a heating time of 5 minutes to obtain a metal clad laminate. The obtained metal clad laminate was subjected to an etching treatment to remove unnecessary parts, thereby forming the conductor wiring 12 on the surface of the resin layer 11. The resin layer 11 on which the conductor wiring 12 was formed on the surface was further hot-pressed at a heating temperature of 250° C., a pressure of 1 MPa, and a heating time of 5 minutes to embed the conductor wiring 12 in the resin layer 11. The width, thickness, and cross-sectional area of the formed conductor wiring 12 were the values shown in Table 1.

[Resin (B) raw material]
As the resin (B) in each of the Examples and Comparative Examples, polycarbonate (manufactured by Mitsubishi Gas Chemical Company, Inc., product name Iupilon, glass transition temperature 89° C.) was used.

[Formation of insulating substrate 13]
The above resin (B) was molded by injection molding to form an insulating substrate 13 having a thickness shown in the "Insulating substrate thickness" column in Table 1.

[Formation of Laminate 1 with Conductor]
The obtained insulating substrate 13 was placed on the surface of the resin layer 11 in which the conductor wiring 12 was embedded, on which the conductor wiring 12 was exposed, and heat pressed at a heating temperature of 250° C., a pressure of 1 MPa, and a heating time of 5 minutes to obtain a conductor-attached laminate 1. At this time, in Examples 1 to 8 and Comparative Examples 1 to 3, the conductor wiring 12 and the insulating substrate 13 were in direct contact with each other. On the other hand, in Comparative Example 4, an acrylic adhesive was interposed between the conductor wiring 12 and the insulating substrate 13 as an adhesive.

[evaluation]
(Glass Transition Temperature of Resin Layer 11)
The glass transition points of the resin layers 11 in Examples 1 to 8 and Comparative Examples 1 to 4 were measured by thermomechanical analysis (TMA).

(Storage Modulus of Resin Layer 11)
The storage modulus of the resin layer 11 was measured under the conditions of atmospheric pressure and humidity of 65% in an air atmosphere. A viscoelasticity measuring device (DMS6220, manufactured by Hitachi High-Technologies Corporation) was used as the measuring device, and the measurement mode was bending (double-supported beam), the measurement temperature range was 25°C to 200°C, and the temperature rise rate was 10°C/min. This resulted in a relationship curve between storage viscoelasticity and temperature. The storage modulus at 25°C (standard state) was read from this relationship curve.

(Volume Resistivity)
A voltage of DC 500 V was applied to the conductor wiring 12 embedded in the resin layer 11 at room temperature (25° C.) using an electrometer device (digital vibration capacitance type electrometer: TAKEDA RIKEN TR8411) to measure the volume resistance of the conductor wiring 12.

(peel strength)
A sample of a laminate 1 with a conductor was prepared under the same conditions as in each of the Examples and Comparative Examples, in which a resin layer 11 having a width of 25 mm in plan view, a conductor wiring 12 having a width of 25 mm in plan view, and an insulating substrate 13 having a width of 25 mm in plan view were sequentially laminated. The peel strength of the conductor wiring 12 from the insulating substrate 13 in this sample was measured according to JIS Z0237 "Test method for adhesive tapes and adhesive sheets."

(Disconnection resistance)
The conductor-attached laminate 1 was stretched at 10 mm/min along the longitudinal direction of the conductor wiring 12 in a thermostatic chamber at 120°C using a tensile tester (Autograph AGS, manufactured by Shimadzu Corporation), and the presence or absence of breakage in the conductor wiring 12 was then confirmed.
A: Even when the resin layer 11 is stretched by 130%, no breakage of the conductor wiring 12 is observed.
B: Even when the resin layer 11 was stretched by 125%, no breakage of the conductor wiring 12 was observed, but when it was stretched by 130%, the conductor wiring 12 was broken.
C: When the resin layer 11 was stretched by 125%, the conductor wiring 12 broke.

According to the above results, in Examples 1 to 8, high resistance to disconnection was obtained. On the other hand, in Comparative Example 1, in which the glass transition temperature of the resin layer 11 (i.e., the glass transition temperature of the resin (A)) was more than 40° C., the resistance to disconnection was low. This is presumed to be because the resin layer 11 was hard, and therefore a strong stress was applied to stretch it, causing disconnection. In Comparative Examples 2 and 3, in which the cross-sectional area of the conductor wiring 12 was less than 0.2×10 ³ μm ² , the resistance to disconnection was also low. This is presumed to be because the cross-sectional area of the conductor wiring 12 is small, and the shape of the conductor wiring 12 is easily unstable, and the durability is insufficient, making it easy to disconnect. In Comparative Example 4, in which the peel strength between the conductor wiring 12 and the insulating substrate 13 was 0.01 N/25 mm or more, the resistance to disconnection was also low. This is presumed to be because the conductor wiring 12 and the insulating substrate 13 were firmly bonded with an adhesive, and therefore the stress when the insulating substrate 13 was stretched was easily transmitted to the conductor wiring 12.

Reference Signs List 1 Laminate with conductor 11 Resin layer 12 Conductor wiring 12a Exposed surface 13 Insulating substrate 2 Planar heater 3 Optical sensor 4 Resin material with conductor

Claims (14)

A resin layer containing a resin (A) having a glass transition temperature of 40° C. or lower;
A resin material with a conductor, the resin material including a conductor wiring having a volume resistivity of 10 μΩcm or less at 25° C.;
An insulating substrate;
At least a portion of the conductor wiring is embedded in the resin layer,
the insulating substrate overlaps the conductor-attached resin material,
the area of a cross section perpendicular to the longitudinal direction of the conductor wiring is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less;
the conductor wiring has an exposed surface exposed from the resin layer at a surface of the conductor-attached resin material facing the insulating substrate, the exposed surface being in direct contact with the insulating substrate;
A laminate with a conductor, wherein the peel strength between the conductor wiring and the insulating substrate is less than 0.01 N/25 mm. A resin layer containing a resin (A) having a glass transition temperature of 40° C. or lower;
A resin material with a conductor, the resin material including a conductor wiring having a volume resistivity of 10 μΩcm or less at 25° C.;
An insulating substrate;
At least a portion of the conductor wiring is embedded in the resin layer,
the insulating substrate overlaps the conductor-attached resin material,
the area of a cross section perpendicular to the longitudinal direction of the conductor wiring is 0.2×10 ³ μm ² or more and 10×10 ³ μm ² or less;
a part of the resin layer is interposed between the conductor wiring and the insulating substrate;
Laminate with conductor. The insulating substrate contains a resin (B) having a glass transition temperature of 80° C. or higher.
The conductor-attached laminate according to claim 1 or 2. The thickness is 75 μm or more and 550 μm or less.
The conductor-attached laminate according to claim 1 . When a tensile load is applied to the resin material with a conductor in at least one direction perpendicular to the thickness direction of the resin layer under at least one temperature atmosphere of -20°C or more and 50°C or less, the elongation of the resin material with a conductor at which breakage occurs in the conductor wiring is 110% or more.
The conductor-attached laminate according to claim 1 . The conductor wiring has a lattice-like, mesh-like, fan-like or meandering shape.
The conductor-attached laminate according to claim 1 . The water contact angle θ of the surface of the insulating substrate is 60° or more.
The conductor-attached laminate according to claim 1 . The conductor-attached laminate has a total light transmittance of 80% or more and a haze value of 2% or less.
The conductor-attached laminate according to claim 1 . A laminate with a conductor according to any one of claims 1 to 8,
Surface heater. The sheet heater according to claim 9 ;
a light receiving unit that receives light transmitted through the planar heater;
Optical sensor. A resin layer and a conductor wiring are provided.
At least a portion of the conductor wiring is embedded in the resin layer,
the resin layer has a first surface facing in a thickness direction thereof and a second surface facing in a direction opposite to the first surface, the conductor wiring is not exposed on either the first surface or the second surface,
The resin layer contains a resin (A) having a glass transition temperature of 40° C. or lower.
Resin material with conductor. The conductor-attached resin material has a total light transmittance of 80% or more and a haze value of 2% or less.
The conductor-attached resin material according to claim 11. When a tensile load is applied to the resin material with a conductor in at least one direction perpendicular to the thickness direction of the resin layer under at least one temperature atmosphere of -20°C or more and 50°C or less, the elongation of the resin material with a conductor at which breakage occurs in the conductor wiring is 110% or more.
The resin material with a conductor according to claim 11 or 12. The thickness is 75 μm or more and 550 μm or less.
The resin material with a conductor according to any one of claims 11 to 13.

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