Conductive film, method for manufacturing conductive film, and temperature sensor film

Abstract

The conductive film (102) of the present invention has a base layer (20) on a hard coat layer formation surface of a resin film base material (50), and has a metal thin film (10) on the base layer, wherein the resin film base material (50) has a hard coat layer (6) on one main surface of a resin film (5). The base layer includes at least one inorganic dielectric thin film. The hard coat layer includes first microparticles having an average primary particle diameter of 10 to 100 nm. In a cross section of the hard coat layer, the area ratio of the first microparticles is preferably 10% or more.

Description

Technical Field

[0001] This invention relates to a temperature sensor film having a patterned metal thin film on a film substrate, a conductive film for making the temperature sensor film, and a method for manufacturing the same. Background Technology

[0002] Multiple temperature sensors are used in electronic devices. These sensors are typically thermocouples or chip thermistors. When measuring the temperature of multiple points within a surface using thermocouples or chip thermistors, a separate temperature sensor needs to be placed at each measurement point and connected to a printed circuit board, thus complicating the manufacturing process. Furthermore, the need to mount multiple sensors on the substrate to measure the temperature distribution within the surface is a major reason for increased costs.

[0003] Patent Document 1 discloses a temperature sensor film in which a metal film is deposited on a film substrate and patterned to form a temperature sensor film with a temperature-sensing resistor section and a lead section. By patterning the metal film, the temperature-sensing resistor section and the lead section connected to the temperature-sensing resistor section can be formed from a single metal film layer, eliminating the need for connecting individual temperature sensors using wiring. Furthermore, due to the use of a film substrate, this temperature sensor film exhibits excellent flexibility and is easily adaptable to curved or flexible components.

[0004] In temperature sensors formed by patterning a metal film, a voltage is applied to a temperature-sensing resistor via a lead wire, and the temperature is measured by utilizing the characteristic that the resistance of the metal changes with temperature. To improve the accuracy of temperature measurement, a material with a large resistance change relative to temperature is preferably selected. According to Patent Document 2, the temperature sensitivity (resistance change) of nickel is approximately twice that of copper.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2005-91045

[0008] Patent Document 2: Japanese Patent Application Publication No. 7-333073 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] A temperature sensor film is obtained by fabricating a conductive film with a metal thin film on a resin film substrate and patterning the metal thin film. When using a resin film substrate, a metal thin film with uniform thickness and properties can be formed on a long strip (e.g., about 10m to 10,000m) of resin film substrate by using continuous film formation methods such as roll-to-roll sputtering.

[0011] When forming conductive films using a roll-to-roll manufacturing process, it is required that the metal film is not easily damaged by friction during roll handling (scratch resistance). Additionally, when the film is bent during roll handling or component assembly, it is required that the metal film is not easily cracked (bending resistance).

[0012] According to the research of the inventors, the following situation exists: for conductive films in which a metal thin film is disposed on a resin film substrate, the scratch resistance or flexural resistance of the metal thin film is not sufficient. During the manufacturing process of the conductive film, the patterning of the metal thin film, and the assembly of the component, defects such as scratches or cracks occur in the metal thin film, resulting in broken lines.

[0013] Further research revealed that by applying a hard coating to the surface of the resin film and then placing a metal film on top of the hard coating, the scratch resistance of the metal film was improved. However, no improvement in flexural resistance was observed even with the hard coating. Furthermore, while placing a metal film on the hard coating improved scratch resistance, it also reduced the adhesion of the metal film, making it prone to peeling off from the resin film substrate during prolonged exposure to high temperatures or high humidity.

[0014] In view of this problem, the object of the present invention is to provide a conductive film having excellent scratch resistance and flexural strength on a resin film substrate, and excellent adhesion of the metal film.

[0015] Technical means to solve the problem

[0016] The conductive film for the temperature sensor has a substrate layer on the hard coating surface of a resin film substrate with a hard coating, and a metal thin film is formed on the substrate layer. The hard coating contains first particles (nanoparticles) with an average primary particle size of 10 to 100 nm. In the cross-section of the hard coating, the area ratio occupied by nanoparticles is preferably 10% or more. In addition to nanoparticles, the hard coating may also contain second particles (microparticles) with an average primary particle size of 0.5 to 3.5 μm.

[0017] Preferably, the substrate layer comprises at least one inorganic dielectric film, and the film directly beneath the metal film is also an inorganic dielectric film. Alternatively, the substrate layer preferably comprises at least one silicon-based film. In one embodiment, the film directly beneath the metal film is a silicon oxide film.

[0018] The preferred arithmetic mean roughness Ra of the metal thin film is 2 nm or more, and the preferred root mean square roughness Rq is 2.5 nm or more. Ra and Rq are determined from a roughness curve with a length of 1 μm. The arithmetic mean roughness Ra of the metal thin film can be less than 25 nm, and the root mean square roughness Rq of the metal thin film can also be less than 40 nm.

[0019] A temperature sensor film can be formed by patterning the metal thin film of a conductive film. The temperature sensor film has a substrate layer and a patterned metal thin film on a hard coating of a resin film substrate. The metal thin film is patterned into a temperature-sensing resistor portion and a lead portion. Alternatively, the substrate layer and the metal thin film can be provided on both sides of the resin film substrate.

[0020] The metal thin film of the conductive film and temperature sensor film preferably has a temperature coefficient of resistance of 3000 ppm / ℃ or higher. The thickness of the metal thin film is preferably 20–500 nm. The metal thin film can also be a nickel-based thin film containing nickel or a nickel alloy.

[0021] The effects of the invention

[0022] In conductive films with a metal thin film disposed on the hard coating surface of a resin film substrate and separated by a base layer, and in temperature sensor films with patterned metal thin films, the metal thin films exhibit high scratch resistance, flexural strength, and adhesion, as well as excellent processability, durability, and reliability. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view showing an example of the stacked structure of a conductive film.

[0024] Figure 2 This is a top view of the temperature sensor membrane.

[0025] Figure 3 This is an enlarged view of the area near the temperature-sensing resistor section of the temperature sensor. A represents a two-wire type, and B represents a four-wire type. Detailed Implementation

[0026] Figure 1 This is a cross-sectional view showing an example of a laminated configuration of a conductive film used to form a temperature sensor film. A metal thin film 10 is provided on one main surface of a resin film substrate 50, and a substrate layer 20 is provided between the resin film substrate 50 and the metal thin film 10. By patterning the metal thin film of this conductive film 102, a... Figure 2 The temperature sensor membrane 110 is shown in a top view.

[0027] [Conductive film]

[0028] <Resin Film Substrate>

[0029] The resin film substrate 50 can be transparent or opaque. For example... Figure 1 As shown, the resin film substrate 50 has a hard coating (cured resin layer) 6 on the surface of the resin film 5. The thickness of the resin film substrate 50 is not particularly limited, generally around 2 to 500 μm, preferably around 20 to 300 μm.

[0030] An easy-bonding layer, an antistatic layer, etc., may be provided on the surface of the resin film 5 and / or the surface of the hard coating 6. Corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputtering etching treatment, etc., may also be performed on the surface of the resin film 5 and / or the surface of the hard coating 6 to improve adhesion, etc.

[0031] (Resin film)

[0032] Examples of resin materials for the resin film 5 include polyesters such as polyethylene terephthalate, polyimide, polyolefins, cyclic polyolefins such as norbornene, polycarbonate, polyethersulfone, and polyarylate. From the viewpoints of heat resistance, dimensional stability, electrical properties, mechanical properties, and chemical resistance, polyimide or polyester is preferred. The thickness of the resin film 5 is not particularly limited, generally ranging from 2 to 500 μm, preferably from 20 to 300 μm.

[0033] (Hard coating)

[0034] By applying a hard coating 6 to the surface of the resin film 5, the hardness of the conductive film is increased, and its scratch resistance is improved. The hard coating 6 can be formed, for example, by coating the resin film 5 with a solution containing a curable resin.

[0035] Examples of curable resins include thermosetting resins, UV-curing resins, and electron beam curing resins. Types of curable resins include polyester-based, acrylic-based, urethane-based, urethane-based, amide-based, silicone-based, silicate-based, epoxy-based, melamine-based, oxetane-based, and urethane-based resins.

[0036] From the viewpoints of high hardness, ability to be cured by ultraviolet light, and excellent manufacturability, acrylic resins, urethane resins, and epoxy resins are preferred. Ultraviolet-curable resins include ultraviolet-curable monomers, oligomers, and polymers. Examples of preferred ultraviolet-curable resins include resins having ultraviolet-polymerizable functional groups, specifically resins containing acrylic monomers or oligomers having two or more, particularly three to six, of these functional groups.

[0037] The hard coating 6, in addition to containing the aforementioned resin components, also contains microparticles (hereinafter sometimes referred to as "microparticles") with an average primary particle size of 10 to 100 nm. By including nanoparticles in the hard coating 6, fine irregularities are formed on the surface of the resin film substrate 50, thereby improving the adhesion between the hard coating 6 and the substrate layer 20 and the metal film 10, as well as the flexural strength of the metal film. From the viewpoint of improving dispersibility, the average primary particle size of the nanoparticles is preferably 20 nm or more. From the viewpoint of forming fine irregularities that contribute to improving adhesion with the substrate layer 20, the average primary particle size of the nanoparticles is preferably 90 nm or less, more preferably 70 nm or less, and even more preferably 50 nm or less.

[0038] In the cross-section of the hard coating, the area ratio occupied by nanoparticles is preferably 10% or more. Alternatively, the area ratio may be 15% or more, or 20% or more. The area ratio occupied by nanoparticles is determined by analyzing transmission electron microscopy (TEM) images of the cross-section of the hard coating.

[0039] There is a tendency that the higher the proportion of nanoparticles, the easier it is to uniformly form unevenness on the surface of the hard coating, thereby improving the adhesion between the substrate layer 20 and the metal film 10, as well as the flexural strength of the metal film 10. On the other hand, when the proportion of nanoparticles is too high, the surface unevenness may become coarse due to particle aggregation. In addition, the surface unevenness may hinder the crystallization of the metal film 10, resulting in a decrease in the temperature coefficient of electrical resistance (TCR). Therefore, the area ratio of nanoparticles in the cross-section of the hard coating is preferably 50% or less, more preferably 45% or less. The area ratio of nanoparticles in the cross-section of the hard coating may also be 40% or less, 35% or less, or 30% or less.

[0040] To ensure that the amount of nanoparticles in the hard coating is within the aforementioned range, the amount of nanoparticles in the composition for forming the hard coating can be adjusted. The amount of nanoparticles relative to 100 parts by weight of the resin component is preferably 10 to 50 parts by weight. The amount of nanoparticles relative to 100 parts by weight of the resin component may also be 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, or 30 parts by weight or less.

[0041] There are no particular limitations on the nanoparticles used; various metal oxide particles such as silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide, glass particles, cross-linked or uncross-linked organic particles containing polymers such as polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate, and organosilicon particles can be used. From the viewpoint of improving dispersibility in the resin adhesive and adhesion to the inorganic materials constituting the substrate 20, inorganic particles are preferred, among which metal oxide particles are preferred, and silicon oxide or aluminum oxide are particularly preferred.

[0042] The hard coating 6 may also contain second particles with a larger particle size than the nanoparticles, in addition to the aforementioned nanoparticles. The average primary particle size of the second particles may be, for example, 0.5–10 μm or 0.8–5 μm. By including microparticles with an average particle size of submicron or micron (hereinafter sometimes referred to as "microparticles"), protrusions with a diameter of submicron or micron are formed on the surface of the hard coating 6 (the surface of the resin film substrate 50) and on the surface of the thin film disposed thereon, thereby tending to improve the sliding properties and anti-adhesion properties of the conductive film. From the viewpoint of uniformly forming protrusions on the surface of the hard coating to improve sliding properties and anti-adhesion properties, the amount of microparticles in the hard coating relative to 100 parts by weight of the resin component is preferably 0.05–20 parts by weight, more preferably 0.1–10 parts by weight.

[0043] The UV polymerization initiator is preferably formulated into the solution used to form the hard coating. Additives such as leveling agents, thixotropic agents, and antistatic agents may also be included in the solution.

[0044] The thickness of the hard coating 6 is not particularly limited, but in order to achieve higher hardness, it is preferably 0.5 μm or more, more preferably 0.8 μm or more, and even more preferably 1 μm or more. Considering the ease of coating formation, the thickness of the hard coating is preferably 15 μm or less, more preferably 10 μm or less.

[0045] When a hard coating contains microparticles, if the thickness of the hard coating is less than or equal to the average primary particle size of the microparticles, protrusions are easily formed on the surface of the hard coating, which is beneficial for improving sliding properties, anti-adhesion properties, and scratch resistance. On the other hand, if the thickness of the hard coating is too small compared to the thickness of the microparticles, the microparticles will detach from the hard coating, resulting in a decrease in sliding properties, anti-adhesion properties, and scratch resistance. The thickness of the hard coating is preferably 0.5 to 1 times the average primary particle size of the microparticles, more preferably 0.6 to 0.9 times.

[0046] The arithmetic mean roughness Ra of the hard coating 6 is preferably 2 nm or more. Ra can also be 2.5 nm or more or 3 nm or more. The root mean square roughness Rq of the hard coating 6 is preferably 2.5 nm or more. Rq can also be 3 nm or more, 3.5 nm or more, 4 nm or more, 4.5 nm or more, or 5 nm or more. There is a tendency that the more nanoparticles contained in the hard coating 6, the larger Ra and Rq will be.

[0047] The arithmetic mean roughness Ra and root mean square roughness Rq were calculated according to JIS B0601:2013 by extracting roughness curves of 1 μm length from a 1 μm square observation image obtained using a scanning probe microscope. The larger the surface roughness Ra and Rq of the hard coating, the better the adhesion of the thin film (substrate layer 20 and metal film 10) formed on the hard coating and the greater the buckling resistance of the metal film.

[0048] On the other hand, when the surface roughness of the hard coating is too large, the crystallization of the metal film is hindered due to the uneven surface, resulting in a decrease in TCR. Therefore, the arithmetic mean roughness Ra of the hard coating 6 is preferably 25 nm or less, and the root mean square roughness Rq of the hard coating 6 is preferably 40 nm or less. Ra can also be 20 nm or less, 15 nm or less, 12 nm or less, or 10 nm or less. Rq can also be 35 nm or less, 30 nm or less, 25 nm or less, 20 nm or less, or 15 nm or less.

[0049] <Basal layer>

[0050] The conductive film 102 has a substrate layer 20 between the hard coating 6 of the resin film substrate 50 and the metal film 10. The substrate layer 20 can be a single layer or, as shown in the figure, can be a single layer. Figure 1 The diagram shows a stacked structure of two or more thin films. The substrate layer 20 can be an organic layer or an inorganic layer, or a substrate layer formed by stacking organic and inorganic layers. Preferably, at least one layer is an inorganic thin film, and it is particularly preferred that the thin film 22 disposed directly below the metal thin film 10 is an inorganic thin film. By using an inorganic thin film as the substrate layer 20, the following tendencies arise: when forming the metal thin film 10, the mixing of organic gases originating from the resin film substrate 50 into the metal thin film 10 is suppressed, the temperature coefficient of resistance (TCR) of the metal thin film 10 increases, thereby improving the temperature measurement accuracy of the temperature sensor film.

[0051] The substrate 20 can be either conductive or insulating. When the thin film 22 disposed directly below the metal thin film 10 is a conductive inorganic material (inorganic conductor), the thin film 21 (or the entire substrate 20) can be patterned together with the metal thin film 10 during the fabrication of the temperature sensor film. When the thin film 21 is an insulating inorganic material (inorganic dielectric), the thin film 21 can be patterned or unpatterned.

[0052] Examples of inorganic materials include metallic or semi-metallic elements such as Si, Ge, Sn, Pb, Al, Ga, In, Tl, As, Sb, Bi, Se, Te, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Ni, Co, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, and Cd, as well as their alloys, nitrides, oxides, carbides, and oxynitrides. From the viewpoint of excellent adhesion between the organic material constituting the hard coating 6 and the metallic material such as nickel constituting the metal thin film 10, and a high degree of effectiveness in suppressing the incorporation of impurities into the metal thin film, silicon-based materials or chromium oxide are preferred as the substrate layer material.

[0053] Examples of silicon-based materials include silicon, as well as silicon compounds such as silicon oxide, silicon nitride, silicon oxynitride, and silicon carbide. From the viewpoint of superior adhesion to hard coatings and metal films, and excellent improvement in flexural strength, silicon or silicon oxide is preferred. From the viewpoint of ensuring insulation between wirings when patterning the metal film 10, the layer 22 directly beneath the metal film 10 is preferably an inorganic dielectric film such as silicon oxide.

[0054] By placing a silicon oxide film 22 with a high resistivity directly below the metal film 10, leakage current between the wiring (patterned metal film) tends to decrease, thus improving the temperature measurement accuracy of the temperature sensor film. The silicon oxide can be of stoichiometric composition (SiO2) or non-stoichiometric composition (SiO2). x ;x < 2). Regarding the non-stoichiometric composition of silicon dioxide (SiO2). x The preferred value is 1.2 ≤ x < 2.

[0055] As the substrate layer 20, a silicon oxide thin film 22 may also be formed on the silicon thin film 21. In addition, from the viewpoint of improving adhesion and flexural strength, as well as improving TCR, a substrate layer 20 having a stack of chromium oxide thin film 21 and silicon oxide thin film 22 is preferred.

[0056] The thickness of the substrate layer 20 and the thickness of the thin film constituting the substrate layer 20 are not particularly limited. From the viewpoint of improving flexural strength through the substrate effect facing the metal thin film 10, and from the viewpoint of reducing plasma damage to the resin film substrate during metal thin film formation or improving the blocking effect of exhaust gas from the resin film substrate, the thickness of the substrate layer 20 is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 5 nm or more. From the viewpoint of improving productivity or reducing material costs, the thickness of the substrate layer is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less.

[0057] <Metal Film>

[0058] The metal thin film 10 disposed on the substrate 20 plays a central role in temperature measurement by the temperature sensor. This is achieved by patterning the metal thin film 10, such as... Figure 2 As shown, a lead portion 11 and a temperature-sensing resistor portion 12 are formed. By providing a metal thin film 10 on the hard coating 6 containing nanoparticles through the substrate layer 20, there is a tendency to improve the adhesion, scratch resistance, and flexural strength without reducing the adhesion.

[0059] Examples of metallic materials constituting the metal thin film 10 include copper, silver, aluminum, gold, rhodium, tungsten, molybdenum, zinc, tin, cobalt, indium, nickel, iron, platinum, palladium, tin, antimony, bismuth, magnesium, and their alloys. Among these, from the viewpoint of low resistivity, high TCR, and low material cost, nickel, copper, or alloys with these as main components (containing 50% by weight or more) are preferred, and nickel, or nickel alloys with nickel as the main component, are particularly preferred.

[0060] The thickness of the metal thin film 10 is not particularly limited. From the viewpoint of reducing resistance (especially reducing the resistance of the lead portion), it is preferably 20 nm or more, more preferably 40 nm or more, and even more preferably 50 nm or more. On the other hand, from the viewpoint of shortening the film deposition time and improving the patterning accuracy, the thickness of the metal thin film 10 is preferably 500 nm or less, more preferably 300 nm or less. Generally speaking, if the thickness of the metal thin film increases, there is a tendency for the residual stress to increase and the adhesion to the resin film substrate to decrease. However, by providing the metal thin film on the hard coating containing nanoparticles with a substrate layer in between, the adhesion is improved. Therefore, even when the thickness of the metal thin film is large, the peeling of the metal thin film from the resin film substrate can be suppressed.

[0061] When the metal thin film 10 is a nickel thin film or a nickel alloy thin film, the resistivity at 25°C is preferably 1.6 × 10⁻⁶. -5 Below Ω·cm, more preferably 1.5×10 -5 Below Ω·cm. From the viewpoint of reducing the resistance of the lead portion, the lower the specific resistance of the metal film, the better; it can also be 1.2 × 10⁻⁶. -5 Below Ω·cm or 1.0×10 -5 Below Ω·cm. Although a lower resistivity is better for metal thin films, it is difficult to make the resistivity lower than that of bulk nickel; the resistivity is typically 7.0 × 10⁻⁶. -6 Ω·cm or higher.

[0062] The TCR of the metal thin film 10 is preferably 3000 ppm / ℃ or higher, more preferably 3400 ppm / ℃ or higher, even more preferably 3600 ppm / ℃ or higher, and particularly preferably 3800 ppm / ℃ or higher. TCR is the rate of change of resistance relative to temperature increase. Metals such as nickel or copper have the characteristic that their resistance increases linearly with increasing temperature (positive characteristic). The TCR of a material with a positive characteristic can be calculated from the resistance value R0 at temperature T0 and the resistance value R1 at temperature T1 using the following formula.

[0063] TCR = {(R1-R0) / R0} / (T1-T0)

[0064] In this specification, the average value of the TCR calculated based on the resistance values ​​at T0 = 25℃ and T1 = 5℃ and the TCR calculated based on the resistance values ​​at T0 = 25℃ and T1 = 45℃ is defined as the TCR of the metal thin film.

[0065] A higher resistivity (TCR) results in a greater change in resistance to temperature variations, leading to higher temperature measurement accuracy of the temperature sensor film. Therefore, a higher TCR for metal thin films is preferable, but it is difficult to achieve a TCR higher than that of bulk metals; the TCR of metal thin films is generally below 6000 ppm / ℃. By setting a substrate layer 20 on a resin film substrate 50 and forming a metal thin film 10 thereon, there is a tendency for the metal thin film to have a lower resistivity and a higher TCR.

[0066] The arithmetic mean roughness Ra of the metal thin film 10 is preferably 2 nm or more. Ra can also be 2.5 nm or more or 3 nm or more. The root mean square roughness Rq of the metal thin film 10 is preferably 2.5 nm or more. Rq can also be 3 nm or more, 3.5 nm or more, 4 nm or more, 4.5 nm or more, or 5 nm or more. There is a tendency that the greater the surface roughness of the metal thin film, the higher the adhesion and buckling resistance of the metal thin film. On the other hand, when the surface roughness of the metal thin film is too large, the TCR (Total Cr Count) decreases. Therefore, the arithmetic mean roughness Ra of the metal thin film 10 is preferably 25 nm or less, and the root mean square roughness Rq of the metal thin film 10 is preferably 40 nm or less. Ra can also be 20 nm or less, 15 nm or less, 12 nm or less, or 10 nm or less. Rq can also be 35 nm or less, 30 nm or less, 25 nm or less, 20 nm or less, or 15 nm or less.

[0067] When a base layer 20 and a metal thin film 10 are formed on a hard coating 6 by a dry coating method such as sputtering, an uneven shape reflecting the surface shape of the hard coating 6 is easily formed on the surface of the metal thin film 10. Therefore, by adjusting the particle size and content of the microparticles contained in the hard coating 6, and making Ra and Rq of the hard coating 6 within the above-mentioned range, a metal thin film 10 having the above-mentioned Ra and Rq can be formed.

[0068] As described above, by forming a metal thin film on a hard coating containing nanoparticles through a substrate layer, the following tendencies are observed: not only is the scratch resistance of the metal thin film improved, but also its flexural strength and adhesion are enhanced, and the total crack resistance (TCR) increases. The improvement in scratch resistance is believed to be due to the increased surface hardness resulting from the application of the hard coating.

[0069] If a metal film is formed on a hard coating containing little or no nanoparticles, the adhesion of the metal film tends to decrease compared to the case where no hard coating is present. On the other hand, if a film is formed on a hard coating containing a specified amount of nanoparticles, the adhesion tends to improve. This is believed to be due to the anchoring effect of the fine irregularities formed by the nanoparticles.

[0070] Furthermore, if a thin film is formed on a hard coating containing a specified amount of nanoparticles, there is a tendency not only to improve adhesion but also to improve the flexural strength of the metal film and suppress the formation of cracks during flexural bending. One of the main reasons for the improved flexural strength is the control of the crystallinity of the metal film. For example, it is presumed that by forming a metal film on a substrate with moderate surface irregularities, the crystallization of the metal film during film formation is moderately hindered, thus leaving behind amorphous portions, which contributes to improved flexural strength.

[0071] <Methods for forming the substrate and metal thin film>

[0072] The method for forming the substrate 20 is not particularly limited; both dry coating and wet coating can be used. When forming a metal thin film by sputtering, from a production point of view, it is preferable that the substrate 20 is also formed by sputtering.

[0073] There are no particular limitations on the method for forming metal thin films. For example, sputtering, vacuum evaporation, electron beam evaporation, chemical vapor deposition (CVD), chemical solution deposition (CBD), and coating methods can be used. Among these, sputtering is preferred from the viewpoint of forming thin films with excellent uniformity of film thickness. By using a roll-to-roll sputtering apparatus, film formation can be performed while continuously moving a long strip of resin film substrate along its length, thereby improving the productivity of conductive films.

[0074] When forming a metal thin film using roll-to-roll sputtering, it is preferable to vent the sputtering apparatus after loading the roll of film substrate into the sputtering apparatus and before starting sputtering to create a gaseous environment in which impurities such as organic gases generated from the film substrate have been removed. By removing the gas from the apparatus and the film substrate beforehand, the amount of moisture or organic gases mixed into the metal thin film 10 can be reduced. Before starting sputtering, the vacuum level (reached vacuum level) in the sputtering apparatus is, for example, 1 × 10⁻⁶. -1Pa or less, preferably 5×10 Pa -2 Pa or less, more preferably 1×10 Pa -2 Pa or less, and more preferably 5 × 10 Pa. -3 Below Pa.

[0075] In the sputtering deposition of metal thin films, a metal target is used, and film deposition is performed while an inert gas such as argon is introduced. For example, when forming a nickel thin film as metal thin film 10, a Ni target is used. When forming a substrate layer by sputtering, the target can be selected according to the material of the substrate layer. For example, when forming a silicon thin film, a silicon target is used. Silicon oxide thin films can be formed using a silicon oxide target, or silicon oxide can be formed by reactive sputtering using a silicon target. Chromium oxide thin films are formed using a Cr target or a chromium oxide target. When forming oxide thin films using a metal target, film deposition is performed by reactive sputtering while an inert gas such as argon and a reactive gas such as oxygen are introduced into the chamber. In reactive sputtering, it is preferable to adjust the oxygen amount so that it forms a transition region between the metal region and the oxide region.

[0076] The sputtering conditions are not particularly limited. To suppress the incorporation of moisture or organic gases into the metal film, it is preferable to minimize damage to the resin film substrate during metal film formation. By providing a substrate layer 20 on the resin film substrate 50 and forming the metal film 10 thereon, plasma damage to the resin film substrate 50 during metal film formation can be suppressed. Furthermore, by providing the substrate layer 20, moisture or organic gases generated from the resin film substrate 50 can be blocked, thereby suppressing the incorporation of moisture or organic gases into the metal film 10.

[0077] Furthermore, by lowering the substrate temperature during film formation and reducing the discharge power density, the generation of moisture or organic gases from the resin film substrate can be suppressed. The substrate temperature during sputtering of metal thin films is preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 170°C or lower. On the other hand, from the viewpoint of preventing embrittlement of the resin film substrate, the substrate temperature is preferably -30°C or higher. From the viewpoint of stabilizing the plasma discharge and suppressing damage to the resin film substrate, the discharge power density is preferably 1 to 15 W / cm². 2 More preferably 1.5–10 W / cm 2 .

[0078] Heat treatment can also be performed after the metal thin film is formed. By heating the conductive film, which has a base layer and a metal thin film on the resin film substrate, the crystallinity of the metal thin film tends to increase, and the TCR (total chromatogram) tends to increase. When performing heat treatment, the heating temperature is preferably 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. The upper limit of the heating temperature can be determined by considering the heat resistance of the resin film substrate, and is generally 200°C or lower or 180°C or lower. When using a film substrate with high heat resistance, such as a polyimide film, the heating temperature can also be higher than the above range. The heating time is preferably 1 minute or more, more preferably 5 minutes or more, and even more preferably 10 minutes or more. The timing of the heat treatment is not particularly limited as long as it is performed after the metal thin film is formed. For example, the heat treatment can also be performed after the metal thin film is patterned.

[0079] [Temperature sensor film]

[0080] A temperature sensor film is formed by patterning the metal thin film 10 of the conductive film. The substrate layer 20 may or may not be patterned. When the layer directly beneath the metal thin film is an insulating material such as silicon oxide, it is not necessary to pattern the substrate layer 20.

[0081] like Figure 2 As shown, in the temperature sensor film, the metal thin film has a lead portion 11 formed in the shape of wiring, and a temperature measuring resistor portion 12 connected to one end of the lead portion 11. The other end of the lead portion 11 is connected to a connector 19.

[0082] The temperature-sensing resistor section 12 functions as a temperature sensor. A voltage is applied to the temperature-sensing resistor section 12 via the lead section 11, and the temperature is calculated based on its resistance value, thereby performing temperature measurement. By providing multiple temperature-sensing resistor sections within the surface of the temperature sensor film 110, the temperature of multiple locations can be measured simultaneously. For example, in... Figure 2 In the manner shown, temperature measuring resistors 12 are provided at 5 locations within the surface.

[0083] Figure 3 A is an enlarged view of the vicinity of the temperature-sensing resistor section of a two-wire temperature sensor. The temperature-sensing resistor section 12 is formed by sensor wiring 122, 123, which are formed by patterning a metal thin film into fine lines. In the sensor wiring, multiple vertical electrodes 122 are connected at their ends via horizontal wiring 123 to form hairpin-shaped bends, thereby having a repeating curved pattern.

[0084] The smaller the linewidth (smaller the cross-sectional area) of the fine lines forming the pattern of the temperature-sensing resistor section 12, and the longer the line length from one end 121a to the other end 121b of the sensor wiring of the temperature-sensing resistor section 12, the greater the resistance between the two points, and the greater the change in resistance with temperature change, thus improving the accuracy of temperature measurement. By forming such a pattern... Figure 3 The repeating, curved wiring pattern shown allows for a smaller area of ​​the temperature-sensing resistor section 12 and a larger length of the sensor wiring (from one end 121a to the other end 121b). It should be noted that the shape of the sensor wiring pattern for the temperature-sensing section is not limited to this. Figure 3 The pattern shown can also be a spiral or other similar shape.

[0085] The linewidth of the sensor wiring 122 (vertical wiring) and the distance between adjacent wirings (spacing width) can be set according to the patterning accuracy of the photolithography method. The linewidth and spacing width are generally around 1 to 150 μm. From the viewpoint of preventing breakage of the sensor wiring, the linewidth is preferably 3 μm or more, preferably 5 μm or more. From the viewpoint of increasing the resistance change and thus improving the accuracy of temperature measurement, the linewidth is preferably 100 μm or less, more preferably 70 μm or less. Similarly, from the same viewpoint, the spacing width is preferably 3 to 100 μm, more preferably 5 to 70 μm.

[0086] The two ends 121a and 121b of the sensor wiring of the temperature-sensing resistor section 12 are respectively connected to one end of the lead sections 11a and 11b. The two lead sections 11a and 11b are arranged in a slightly spaced-apart, elongated pattern, and the other end of the lead sections is connected to the connector 19. To ensure sufficient current capacity, the lead sections are wider than the sensor wiring of the temperature-sensing resistor section 12. The width of the lead sections 11a and 11b is, for example, about 0.5 to 10 mm. The line width of the lead sections is preferably 3 times or more than 5 times, and more preferably 10 times or more than the line width of the sensor wiring 122 of the temperature-sensing resistor section 12.

[0087] Connector 19 has multiple terminals, with multiple leads connected to different terminals. Connector 19 connects to an external circuit. By applying a voltage between lead 11a and lead 11b, current flows through lead 11a, temperature-sensing resistor 12, and lead 11b. The resistance value is calculated based on the current value when a specified voltage is applied, or the applied voltage when the current is applied in a manner that results in a specified value. The temperature is calculated based on the obtained resistance value and a pre-calculated temperature relationship, or a table recording the relationship between resistance value and temperature.

[0088] The resistance value calculated here includes not only the resistance of the temperature-sensing resistor section 12, but also the resistance of the lead sections 11a and 11b. However, since the resistance of the temperature-sensing resistor section 12 is much larger than the resistance of the lead sections 11a and 11b, the calculated value can be considered as the resistance of the temperature-sensing resistor section 12. It should be noted that, from the viewpoint of reducing the influence caused by the resistance of the lead sections, the lead sections can also be set to a four-wire type.

[0089] Figure 3 B is an enlarged view of the area near the temperature sensing resistor section of the four-wire temperature sensor. The pattern shape of the temperature sensing resistor section 12 is similar to... Figure 3 A is the same. In the four-wire type, four lead sections 11a1, 11a2, 11b1, and 11b2 are connected to one temperature-sensing resistor section 12. Lead sections 11a1 and 11b1 are voltage measurement leads, and lead sections 11a2 and 11b2 are current measurement leads. The voltage measurement lead 11a1 and the current measurement lead 11a2 are connected to one end 121a of the sensor wiring of the temperature-sensing resistor section 12, and the voltage measurement lead 11b1 and the current measurement lead 11b2 are connected to the other end 121b of the sensor wiring of the temperature-sensing resistor section 12. In the four-wire type, since the resistance of the lead sections can be excluded and only the resistance value of the temperature-sensing resistor section 12 is measured, a measurement with less error can be achieved. In addition to the two-wire and four-wire types, the three-wire type can also be used.

[0090] There is no particular limitation on the patterning method for metal thin films. From the viewpoint of ease of patterning and high precision, patterning by photolithography is preferred. In photolithography, a resist corresponding to the shape of the aforementioned lead portion and temperature-sensing resistor portion is formed on the surface of the metal thin film. After removing the metal thin film in areas where no resist is formed by wet etching, the resist is stripped off. Patterning of metal thin films can also be performed by dry etching such as laser processing.

[0091] In the above embodiment, by providing a base layer 20 on the hard coating 6 of the resin film substrate 50, forming a metal thin film 10 by sputtering or the like, and patterning the metal thin film, multiple lead portions and temperature-sensing resistor portions can be formed within the substrate surface. A temperature sensor element is obtained by connecting a connector 19 to the end of the lead portion 11 of the temperature sensor film. In this embodiment, multiple temperature-sensing resistor portions are connected to lead portions, and multiple lead portions are connected to one connector 19. Therefore, a temperature sensor element capable of measuring the temperature of multiple locations within a surface can be easily formed.

[0092] In the above embodiments, a hard coating is formed on one main surface of the resin film substrate, and a base layer and a metal film are formed thereon. However, a hard coating can also be formed on both sides of the resin film substrate, and a base layer and a metal film can be formed on each main surface. Alternatively, a base layer and a metal film can be formed on the hard coating on one main surface of the resin film substrate, and a film composed of different layers can be formed on the other main surface.

[0093] The connection method between the lead portion of the temperature sensor film and the external circuit is not limited to a connection via a connector. For example, a controller for applying voltage to the lead portion and measuring resistance can be provided on the temperature sensor film. Alternatively, the lead portion can be connected to lead wiring from the external circuit via soldering or the like without a connector.

[0094] Temperature sensor films are simple structures consisting of a thin film deposited on a resin film substrate. They offer excellent manufacturability and flexural strength, making them easy to process and handle. They can also be applied to curved components or flexible components with bends. Furthermore, due to the high temperature coefficient (TCR) of the metal thin film, more accurate temperature measurement can be achieved. Moreover, in embodiments of the present invention, the high adhesion of the metal thin film allows for the formation of temperature sensor films with excellent processability, durability, and reliability.

[0095] Example

[0096] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0097] [Example 1]

[0098] (Preparation of hard coating composition)

[0099] A hard coating composition using methyl isobutyl ketone as a solvent is prepared by mixing 15 parts by weight of silica particles (CSZ9281 manufactured by CIK NanoTek) with an average primary particle size of 30 nm as the solid component, relative to 100 parts by weight of the resin component of UV-curable urethane acrylic resin (Aica Industrial "Aica ITRON Z844-22HL").

[0100] (Fabrication of film substrates with hard coating)

[0101] The hard coating composition was applied to one side of a 150 μm thick polyethylene terephthalate (PET) film (Toray's "Lumirror 149UNS"; Ra = 1.5 nm, Rq = 1.9 nm) and dried at 100°C for 1 minute. Then, it was cured by ultraviolet irradiation to form a 1.2 μm thick hard coating. The arithmetic mean roughness Ra of the hard coating surface was 3.4 nm, the root mean square roughness Rq was 4.4 nm, and the area ratio of nanoparticles in the cross-section of the hard coating was 16%.

[0102] (Thin film formation)

[0103] A roll of the hard-coated film substrate is placed inside a roll-to-roll sputtering apparatus, and the sputtering apparatus is evacuated to a vacuum level of 5 × 10⁻⁶. -3 Following Pa, at a substrate temperature of 150°C, a 5 nm thick silicon film, a 10 nm thick silicon oxide film, and a 160 nm thick nickel film were sequentially deposited on the hard coating surface by DC sputtering. The Si and SiO2 layers were formed using a boron-doped Si target. For the Si layer, argon gas was introduced as the sputtering gas at a pressure of 0.3 Pa and a power density of 1.0 W / cm². 2 Film formation was carried out under the following conditions. For the SiO2 layer, in addition to argon as the sputtering gas, oxygen was also introduced as a reactive gas (O2 / Ar = 1 / 1), at a pressure of 0.3 Pa and a power density of 1.8 W / cm². 2 Film formation was performed under the following conditions. The nickel layer was formed using a metallic nickel target, with argon gas introduced as the sputtering gas at a pressure of 0.3 Pa and a power density of 5.0 W / cm³. 2 Film formation is carried out under the specified conditions.

[0104] [Example 2]

[0105] In the preparation of the hard coating composition, in addition to 15 parts by weight of silica particles with an average primary particle size of 30 nm, 0.2 parts by weight of cross-linked polymethyl methacrylate particles ("techpolymer SSX-101" manufactured by Sekisui Chemicals) with an average primary particle size of 1.55 μm were added, relative to 100 parts by weight of the resin component. Otherwise, similar to Example 1, a film substrate with a hard coating was prepared, and a silicon film, a silica film, and a nickel film were formed thereon.

[0106] [Example 3]

[0107] In the preparation of the hard coating composition, 15 parts by weight of alumina particles (“NanoTek” manufactured by CIK NanoTek) with an average primary particle size of 30 nm were used instead of silicon oxide particles with an average primary particle size of 30 nm. The area ratio of nanoparticles in the cross-section of the hard coating is 16%. Otherwise, similar to Example 2, a film substrate with a hard coating was prepared, and a silicon thin film, a silicon oxide thin film, and a nickel thin film were formed thereon.

[0108] [Example 4]

[0109] In the thin film formation, a 7nm thick chromium oxide thin film is formed instead of a 5nm thick silicon thin film, configured as a chromium oxide / silicon oxide / nickel stack. The chromium oxide thin film is formed using a metallic Cr target, and oxygen is introduced as a reactive gas in addition to argon as the sputtering gas (O2 / Ar = 1 / 1), at a pressure of 0.3 Pa and a power density of 1.8 W / cm³. 2 Films are formed under the conditions specified in Example 2. Otherwise, similar to Example 2, chromium oxide film, silicon oxide film, and nickel film are formed on the film substrate with a hard coating.

[0110] [Examples 5-8 and Comparative Examples 3 and 4]

[0111] By varying the amount of silicon oxide particles added and the composition of the substrate film as shown in Table 1, a film substrate with a hard coating was fabricated and a film was formed onto the hard coating.

[0112] In Comparative Examples 3 and 4, which do not contain nanoparticles, the arithmetic mean roughness Ra of the hard coating surface is 0.3 nm, and the root mean square roughness Rq is 0.3 nm.

[0113] In Comparative Example 4, in which 7 parts by weight of nanoparticles were added relative to 100 parts by weight of resin, the arithmetic mean roughness Ra of the hard coating surface was 2.0 nm, the root mean square roughness Rq was 2.2 nm, and the area ratio of nanoparticles in the cross section of the hard coating was 8%.

[0114] In Examples 5 and 6, in which 25 parts by weight of nanoparticles were added relative to 100 parts by weight of resin, the arithmetic mean roughness Ra of the hard coating surface was 6.7 nm, the root mean square roughness Rq was 9.2 nm, and the area ratio of nanoparticles in the cross section of the hard coating was 37%.

[0115] In Examples 7 and 8, in which 40 parts by weight of nanoparticles were added relative to 100 parts by weight of resin, the arithmetic mean roughness Ra of the hard coating surface was 15.1 nm, the root mean square roughness Rq was 18.9 nm, and the area ratio of nanoparticles in the cross section of the hard coating was 42%.

[0116] [Comparative Example 1]

[0117] Without setting a hard coating layer and a substrate layer, a nickel film with a thickness of 160 nm is formed on a PET film by DC sputtering.

[0118] [Comparative Example 2]

[0119] Without a hard coating, a silicon film, a silicon oxide film, and a nickel film are sequentially formed on a PET film by DC sputtering under the same conditions as in Example 1.

[0120] [evaluate]

[0121] The following evaluation was performed on the hard-coated film substrates and conductive films prepared in the examples and comparative examples.

[0122] <Nanoparticle quantity in the hard coating section>

[0123] The cross-section of the film substrate with hard coating was observed by SEM. The observed image was binarized and analyzed to determine the area ratio occupied by nanoparticles (silicon oxide particles with an average primary diameter of 30 nm).

[0124] <Surface Shape>

[0125] Using an atomic force microscope (Bruker's "Dimension 3100"), the three-dimensional surface shape was determined under the following conditions, and a roughness curve with a length of 1 μm was extracted. According to JIS B0601, the arithmetic mean roughness Ra and root mean square roughness Rq were calculated.

[0126] Controller: NanoscopeV

[0127] Measurement mode: Tapping mode

[0128] Cantilever: Si single crystal

[0129] Measurement field of view: 1μm × 1μm

[0130] <Temperature coefficient of resistance>

[0131] (Preparation of the test sample)

[0132] The conductive film was cut to a size of 10mm × 200mm, and the nickel layer was patterned using laser to create stripes with a line width of 30μm, forming... Figure 3 A temperature-sensing resistor section with the shape shown in Figure A. During patterning, the length of the pattern is adjusted so that the overall wiring resistance is about 10kΩ and the resistance of the temperature-sensing resistor section is 30 times the resistance of the lead section, to produce a sample (temperature sensor film) for measurement.

[0133] (Determination of temperature coefficient of resistance)

[0134] Using a small heating and cooling oven, the temperature resistance section of the temperature sensor film was heated to 5°C, 25°C, and 45°C. One end of the lead wire was connected to the other end of the tester, a constant current was flowed through it, and the voltage was read, thereby measuring the resistance of the two terminals at each temperature. The average value of the TCR calculated based on the resistance values ​​at 5°C and 25°C and the TCR calculated based on the resistance values ​​at 25°C and 45°C was set as the TCR of the nickel layer.

[0135] (Determination of the temperature coefficient of resistance of the conductive film after heat treatment)

[0136] After heating the conductive film in a hot air oven at 155°C for 1 hour, a temperature sensor film was fabricated in the same order as described above, and the TCR of the nickel layer was measured.

[0137] <Seamlessness>

[0138] The following evaluations were performed on the following samples: the untreated sample after film formation (initial stage), the sample after a 500-hour heating durability test in a hot air oven at 80°C (after heating test), and the sample after a 500-hour high temperature and high humidity durability test in a constant temperature and humidity bath at 65°C and 90% relative humidity (after high temperature and high humidity test).

[0139] On the nickel film forming surface of the conductive film, cuts are made at 1mm intervals along both the longitudinal and transverse directions using a cutting tool to form a 100-grid checkerboard pattern. A peel test is then performed according to the old JIS-K5400 checkerboard test, counting the number of checkerboard patterns where the film peels off in areas exceeding 1 / 4 of the grid area. The smaller the number, the higher the adhesion.

[0140] <Bending resistance>

[0141] According to JIS K5600-5-1:1999, cylindrical mandrel tests were conducted using a type 1 testing machine. Two tests were performed: buckling with the Ni layer forming surface of the specimen as the inner side (imposing compressive strain on the Ni layer), and buckling with the Ni layer forming surface as the outer side (imposing tensile strain on the Ni layer). In each test, the diameter of the mandrel was successively decreased, and the diameter at which cracks began to appear in the Ni layer was recorded. A smaller mandrel diameter indicates better buckling resistance.

[0142] Abrasion resistance

[0143] Steel wool ("Bonstar#0000" manufactured in Japan) was fixed to the plane of a 10mm φ cylindrical fixture and passed through an abrasion tester with a load of 50g / cm². 2 A scratch test was conducted 10 times under the conditions of a sliding interval of 100 mm and a sliding speed of 100 mm / s. The surface of the nickel film was visually confirmed to be free of scratches after the test, and the evaluation was based on the following criteria.

[0144] ○: Number of scars is 14 or less

[0145] △: The number of scars is 15 to 50.

[0146] ×: The number of scars is 51 or more.

[0147] <Anti-blocking properties>

[0148] A smooth film (manufactured by Zeon, Japan, "ZEONOR film ZF-16") was pressed onto the Ni thin film forming surface of the conductive film with a finger, and the adhesion between the films was visually observed. The evaluation was based on the following criteria.

[0149] ○: No adhesion occurred immediately after crimping.

[0150] △: Adhesion occurs immediately after crimping, but the adhesion disappears over time.

[0151] ×: Adhesion occurs immediately after crimping and does not disappear even after time has passed.

[0152] Table 1 shows the composition of the conductive films in the embodiments and comparative examples (particle content in the hard coating and composition of the substrate layer), as well as the evaluation results of the conductive films (surface roughness, temperature coefficient of resistance, adhesion, flexural strength, scratch resistance and adhesion resistance).

[0153] [Table 1]

[0154]

[0155] In Comparative Example 1, where a nickel film was directly formed on a PET film, the flexural strength and scratch resistance were poor, and the adhesion resistance was not adequate. Furthermore, compared to other examples, the conductive film of Comparative Example 1 had a lower initial TCR, and no increase in TCR was observed after heating.

[0156] In Comparative Example 2, where a silicon film and a silicon oxide film are formed on a PET film as a base layer, and a nickel film is formed thereon, the TCR was observed to increase compared to Comparative Example 1, but the flexural strength, scratch resistance, and adhesion resistance were the same as those of Comparative Example 1.

[0157] In Comparative Example 3, where a hard coating containing microparticles is formed on a PET film, and a base layer and a nickel film are formed thereon, the surface roughness Ra and Rq of the nickel film are smaller compared to Comparative Examples 1 and 2. It is believed that by forming the hard coating through wet coating, the surface irregularities of the PET film are filled and smoothed, thereby reducing the surface roughness of the film disposed thereon.

[0158] In Comparative Example 3, which has a hard coating containing microparticles but not nanoparticles, scratch resistance and adhesion resistance are improved, and the TCR is increased compared to Comparative Examples 1 and 2. However, in Comparative Example 3, the adhesion of the sample is significantly reduced after the heating test (80°C, 500 hours) and the high temperature and high humidity test (65°C, 90% RH, 500 hours).

[0159] In Comparative Example 4, where 7 parts by weight of nanoparticles were added to the hard coating in addition to 0.2 parts by weight of microparticles (nanoparticle ratio in the cross section of the hard coating: 8%), the adhesion was improved compared to Comparative Example 3, but the adhesion after the high temperature and high humidity test was not sufficient. Furthermore, no significant improvement in flexural strength was observed in Comparative Example 4.

[0160] In Examples 1-8, where the amount of nanoparticles was greater than that of Comparative Example 4, the samples exhibited excellent adhesion and improved flexural strength after both the heating test and the high-temperature and high-humidity test. A comparison between Example 1 and Example 2 shows that adding a small amount of microparticles to the nanoparticle base improves adhesion resistance.

[0161] In Comparative Examples 4 and Examples 1-8, it was observed that as the amount of nanoparticles in the hard coating increased, the surface roughness Ra and Rq tended to increase, and the adhesion and buckling resistance tended to improve accordingly. On the other hand, it was observed that as the amount of nanoparticles increased, the TCR tended to decrease, but in each example, it showed a higher TCR than that of Comparative Example 1, which did not contain a substrate layer.

[0162] As can be seen from the comparison of the above embodiments and comparative examples, by forming a hard coating containing a specified amount of nanoparticles on the resin film and forming a metal film on it with a substrate layer in between, a conductive film with excellent scratch resistance, flexural resistance and adhesion, and high TCR can be obtained.

[0163] Explanation of reference numerals in the attached figures

[0164] 50: Resin film substrate

[0165] 5: Resin film

[0166] 6: Hard coating

[0167] 20: Basal layer

[0168] 10: Metal film

[0169] 11: Lead wire section

[0170] 12: Temperature Measurement Resistance Section

[0171] 122, 123: Sensor wiring

[0172] 19: Connector

[0173] 102: Conductive film

[0174] 110: Temperature sensor membrane

Claims

1. A conductive film for a temperature sensor, comprising: a resin film substrate having a hard coat layer on a surface of a resin film; a base layer provided on a hard coat layer formation surface of the resin film substrate; and a metal thin film provided on the base layer, wherein the base layer comprises at least one inorganic dielectric thin film, wherein the hard coat layer comprises first particles having an average primary particle diameter of 10 nm to 100 nm and second particles having an average primary particle diameter of 0.5 μm to 3.5 μm, and wherein an area ratio of the first particles in a cross section of the hard coat layer is 10% or more. wherein an arithmetic average roughness of the metal thin film, calculated from a roughness curve having a length of 1 μm, is 2 nm to 25 nm, wherein a root mean square roughness of the metal thin film, calculated from a roughness curve having a length of 1 μm, is 2.5 nm to 40 nm, wherein a thickness of the hard coat layer is 0.5 times to 1 times an average primary particle diameter of the second particles, wherein the base layer comprises at least one silicon-based thin film, wherein a thickness of the metal thin film is 20 nm to 500 nm, wherein the metal thin film comprises nickel or a nickel alloy, wherein a temperature coefficient of resistance of the metal thin film is 3000 ppm / °C or more, and wherein the metal thin film is patterned.

9. A method for producing a conductive film according to any one of claims 1 to 8, wherein the metal thin film is formed by a sputtering method.

10. A temperature sensor film, comprising: a resin film substrate having a hard coat layer on a surface of a resin film; a base layer provided on a hard coat layer formation surface of the resin film substrate; and a metal thin film provided on the base layer and patterned, wherein the metal thin film is patterned into a temperature measuring resistor portion and a lead portion, the temperature measuring resistor portion is patterned into a fine line and used for measuring a temperature, and the lead portion is connected to the temperature measuring resistor portion and patterned into a line having a larger width than the temperature measuring resistor portion, wherein the base layer comprises at least one inorganic dielectric thin film, wherein the hard coat layer comprises first particles having an average primary particle diameter of 10 nm to 100 nm and second particles having an average primary particle diameter of 0.5 μm to 3.5 μm, and wherein an area ratio of the first particles in a cross section of the hard coat layer is 10% or more. ​ ​ ​ ​ 2. The conductive film for a temperature sensor according to claim 1, wherein ​ 3. The conductive film for a temperature sensor according to claim 1 or 2, wherein ​ 4. The conductive film for a temperature sensor according to claim 1 or 2, wherein ​ 5. The conductive film for a temperature sensor according to claim 1 or 2, wherein ​ 6. The conductive film for a temperature sensor according to claim 1 or 2, wherein ​ 7. The conductive film for a temperature sensor according to claim 1 or 2, wherein ​ 8. The conductive film for a temperature sensor according to claim 1 or 2, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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