KR20210124211A - Conductive film, conductive film winding body, manufacturing method thereof, and temperature sensor film - Google Patents

Abstract

The conductive film 101 includes a metal thin film 10 on one main surface of a resin film base material 50 . As for the arithmetic mean roughness Ra1 calculated|required from the 1 micrometer-length roughness curve of the surface of a metal thin film, 2 nm or less is preferable. As for the maximum height Rz2 calculated|required from the roughness curve of length 0.7mm of the surface of a metal thin film, 150 nm or more is preferable. The resin film base material 50 may be equipped with the hard-coat layer 6 on the surface of the resin film 5. As shown in FIG. A temperature sensor film can be manufactured by patterning the metal thin film of a conductive film.

Description

Conductive film, conductive film winding body, manufacturing method thereof, and temperature sensor film

The present invention relates to a conductive film having a metal thin film on a film substrate, and a temperature sensor film having a patterned metal thin film on the film substrate.

A number of temperature sensors are used in electronic devices. As a temperature sensor, a thermocouple and a chip thermistor are common. In the case of measuring the temperature of a plurality of points in a plane by a thermocouple, a chip thermistor, etc., since it is necessary to arrange a temperature sensor for each measurement point and connect each temperature sensor to a printed wiring board, etc., a manufacturing process becomes complicated. Moreover, in order to measure an in-plane temperature distribution, it is necessary to arrange|position a large number of sensors on a board|substrate, and it becomes a factor of cost increase.

Patent Document 1 proposes a temperature sensor film in which a metal film is formed on a film substrate and the metal film is patterned to form a resistance thermometer and a lead portion. In the form of patterning the metal film, it is possible to form a resistance temperature measurement portion and a lead portion connected to the resistance temperature measurement portion from one layer of metal film, and it is not necessary to connect individual temperature measurement sensors with wiring. Moreover, since it uses a film base material, it has the advantage that it is excellent in flexibility and it is also easy to respond|correspond to large-area increase.

In a temperature sensor in which a metal film is patterned, a voltage is applied to a resistance thermometer through a lead portion, and the temperature is measured using the characteristic that the resistance value of the metal changes with temperature. In order to increase the accuracy of temperature measurement, a material having a large change in resistance to temperature change is preferable. Patent document 2 describes that nickel has about twice the sensitivity (resistance change) with respect to temperature compared with copper.

Japanese Laid-Open Patent Publication No. 2005-91045 Japanese Patent Laid-Open No. 7-333073

A temperature sensor film is obtained by manufacturing a conductive film provided with a metal thin film on a film base material, and patterning a metal thin film. In the case of using a film substrate, by employing a continuous film formation method such as roll-to-roll sputtering, on a long (for example, about 10 m to 10,000 m) film substrate, the film thickness and characteristics are uniform. A metal thin film can be formed.

Metals such as nickel exhibit a characteristic (positive characteristic) in which resistance increases as the temperature increases, and bulk nickel has a rate of change of resistance with respect to temperature rise (temperature coefficient of resistance; TCR) of about 6000 ppm/° C. that is known On the other hand, as a result of the present inventors forming a nickel thin film by sputtering method on the resin film base material, and evaluating the characteristic, the temperature coefficient of resistance (TCR) is about half that of bulk nickel, and the temperature at the time of using as a temperature sensor film It turned out that there is room for improvement in measurement precision. Moreover, it became clear that the conductive film in which the thin metal film was formed on the elongate resin film base material also had a subject also in running stability of the film resulting from blocking, abrasion resistance of a metal thin film, etc.

In view of the said subject, this invention is equipped with the metal thin film with a large resistance temperature coefficient on a resin film base material, and aims at provision of the electrically conductive film excellent in slidability.

MEANS TO SOLVE THE PROBLEM When the present inventors have the predetermined|prescribed surface shape formed on the resin film base material, it discovers that the rise of a resistance temperature coefficient and the sliding property of a film are compatible, and led to this invention.

The conductive film for temperature sensors is provided with a metal thin film on one main surface of a resin film base material. As for the arithmetic mean roughness Ra1 calculated|required from the 1 micrometer-length roughness curve of the surface of a metal thin film, 2 nm or less is preferable. As for the maximum height Rz2 calculated|required from the roughness curve of length 0.7mm of the surface of a metal thin film, 150 nm or more is preferable. The roll-shaped wound body of an elongate film may be sufficient as an electrically conductive film.

A temperature sensor film can be formed by patterning the metal thin film of a conductive film. The temperature sensor film is provided with a metal thin film patterned on one main surface of a resin film substrate, and the metal thin film is patterned with a resistance thermometer and a lead part. A thin metal film may be formed on both surfaces of the resin film substrate.

It is preferable that the metal thin film of a conductive film and a temperature sensor film has a resistance temperature coefficient of 3100 ppm/degreeC or more. As for the thickness of a metal thin film, 20-500 nm is preferable. The metal thin film may be a nickel-based thin film made of nickel or a nickel alloy.

The resin film base material may be equipped with a hard-coat layer on the surface of a resin film. When a resin film base material is equipped with a hard-coat layer, it is preferable to form a metal thin film directly or via another layer on a hard-coat layer. The hard-coat layer may contain microparticles|fine-particles.

The conductive film of this invention has a large resistance-temperature coefficient and is excellent in sliding property. Therefore, when a conductive film is wound in roll shape, blocking does not generate|occur|produce easily, and while it is excellent in the runability of the film at the time of roll conveyance, the temperature sensor film obtained by patterning a metal thin film can implement|achieve high temperature measurement precision.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the laminated|stacked structural example of a conductive film.
2 : is sectional drawing which shows the laminated|stacked structural example of a conductive film.
3 is a plan view of a temperature sensor film.
Fig. 4 is an enlarged view of the vicinity of a resistance thermometer in a temperature sensor, where A is a two-wire type, and B is a four-wire type.

1 : is sectional drawing which shows the laminated|stacked structural example of the conductive film used for formation of a temperature sensor film, and the metal thin film 10 is provided on one main surface of the resin film base material 50. As shown in FIG. By patterning the metal thin film of this conductive film 101, the temperature sensor film 110 shown in the top view of FIG. 3 is obtained.

[conductive film]

<Film base material>

The resin film base material 50 may be transparent or may be opaque. The resin film base material 50 may consist only of a resin film, and may provide the hard-coat layer (hardened resin layer) 6 on the surface of the resin film 5, as shown in FIG. Although the thickness of the resin film base material 50 is not specifically limited, Generally, it is about 2-500 micrometers, and about 20-300 micrometers is preferable.

An easily bonding layer, an antistatic layer, etc. may be formed in the surface of the resin film base material 50 (when the hard-coat layer 6 is formed, the surface of the hard-coat layer 6). On the surface of the resin film base material 50, corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputter etching, etc. for the purpose of adhesive improvement with the metal thin film 10 (or the base layer 20). You may perform a process, such as a process.

As for the metal thin film 10 formation surface of the resin film base material 50, it is preferable that arithmetic mean roughness Ra1 calculated|required from the roughness curve of 1 micrometer in length is 2 nm or less. By making Ra1 of the film base material small, Ra1 of the metal thin film 10 formed thereon also tends to become small. The smaller Ra1 of the metal thin film, the larger the temperature coefficient of resistance (TCR) tends to be. Ra1 of the resin film base material 50 may be 1.5 nm or less, 1.2 nm or less, or 1.0 nm or less.

As for the metal thin film 10 formation surface of the resin film base material 50, it is preferable that the maximum height Rz2 calculated|required from the roughness curve of length 0.7mm is 150 nm or more. By enlarging Rz2 of a film base material, Rz2 of the metal thin film 10 formed thereon also becomes large, and there exists a tendency for the sliding property and blocking resistance of a conductive film to improve.

It is preferable that the arithmetic mean roughness Ra2 calculated|required from the roughness curve of length 0.7mm of the metal thin film 10 formation surface of the resin film base material 50 is about 0.5-25 nm, and 1-20 nm is more preferable. When Ra2 is within the above range, unevenness is formed on the surface of the metal thin film 10, and it is possible to provide moderate sliding properties.

Ra1 is computed from the roughness curve of 1 micrometer in length extracted from the three-dimensional surface shape measured using the scanning probe microscope. Ra2 and Rz2 are calculated from roughness curves with a length of 0.7 mm extracted from a three-dimensional surface shape measured by a vertical scanning low coherence interferometry (ISO25178). Both the arithmetic mean roughness Ra and the maximum height Rz follow the definition of JIS B0601:2013.

(resin film)

As a resin material of the resin film 5, polyester, such as a polyethylene terephthalate, polyimide, polyolefin, cyclic polyolefins, such as a norbornene type, polycarbonate, polyethersulfone, polyarylate, etc. are mentioned. From the viewpoints of heat resistance, dimensional stability, electrical properties, mechanical properties, chemical resistance properties, and the like, polyimide or polyester is preferable. Although the thickness of the resin film 5 is not specifically limited, Generally, it is about 2-500 micrometers, and about 20-300 micrometers is preferable.

(hard coat layer)

When the hard-coat layer 6 is formed in the surface of the resin film 5, the hardness of a conductive film improves and the abrasion resistance of a conductive film becomes high. The hard-coat layer 6 can be formed by apply|coating the solution containing curable resin on the resin film 5, for example.

As curable resin, thermosetting resin, ultraviolet curable resin, electron beam curable resin, etc. are mentioned. Examples of the curable resin include various resins such as polyester, acrylic, urethane, acrylic urethane, amide, silicone, silicate, epoxy, melamine, oxetane, and acrylic urethane.

Among these, an acrylic resin, an acrylic urethane-type resin, and an epoxy-type resin are preferable at the point which hardness is high, ultraviolet curing is possible, and it is excellent in productivity. The ultraviolet curable resin includes ultraviolet curable monomers, oligomers, polymers, and the like. The ultraviolet curable resin preferably used includes, for example, those containing an acrylic monomer or oligomer having two or more functional groups, particularly those having three to six functional groups, as a component having an ultraviolet polymerizable functional group.

The hard-coat layer 6 may contain microparticles|fine-particles. By including microparticles|fine-particles in the hard-coat layer 6, the surface shape of the metal thin film 10 formation surface of the resin film base material 50 can be adjusted. Examples of the fine particles include fine particles of various metal oxides such as silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide, fine glass particles, polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene. Crosslinked or uncrosslinked organic microparticles, silicone microparticles, etc. made of polymers such as copolymer, benzoguanamine, melamine, and polycarbonate can be used without particular limitation.

0.5-10 micrometers is preferable and, as for the average particle diameter of microparticles|fine-particles, 0.8-5 micrometers is more preferable. By adding microparticles having an average particle diameter of sub-micron or micrometer order, irregularities are formed on the surface of the hard coat layer 6 (the surface of the resin film substrate 50) and the surface of the metal thin film 10 formed thereon. Thus, the slip property and blocking resistance of the conductive film can be improved. Further, when the particle diameter of the fine particles is on the order of submicrons or mu m, the unevenness has an appropriate size, so that when viewed on a nm scale, the surface becomes smooth and Ra1 tends to be small. From a viewpoint of uniformly forming unevenness|corrugation on the whole surface of a hard-coat layer, 0.05-50 weight part is preferable with respect to 100 weight part of resin components, and, as for the quantity of microparticles|fine-particles, 0.1-30 weight part is more preferable.

It is preferable that the ultraviolet-ray polymerization initiator is mix|blended with the solution for forming a hard-coat layer. Additives, such as a leveling agent, a thixotropic agent, and an antistatic agent, may be contained in a solution.

Although the thickness of the hard-coat layer 6 is not specifically limited, In order to implement|achieve high hardness, 0.5 micrometer or more is preferable, 0.8 micrometer or more is more preferable, 1 micrometer or more is still more preferable. When the easiness of formation by application|coating is considered, 15 micrometers or less are preferable and, as for the thickness of a hard-coat layer, 10 micrometers or less are more preferable.

When the resin film base material 50 does not have a hard-coat layer, you may adjust the surface shape of a film base material by making the resin film 5 contain microparticles|fine-particles of a submicron or micrometer order.

<Metal thin film>

The metal thin film 10 formed on the base layer 20 plays a central role of temperature measurement in a temperature sensor. By patterning the metal thin film 10 , a lead portion 11 and a temperature resistance portion 12 are formed as shown in FIG. 3 .

Examples of the metal material 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 alloys thereof. Among these, nickel, copper, or an alloy containing these as a main component (including 50% by weight or more) is preferable from the viewpoint of low resistance, high temperature coefficient of resistance (TCR), and inexpensive material, and particularly nickel or nickel A nickel alloy containing as a main component is preferred.

Although the thickness of the metal thin film 10 is not specifically limited, From a viewpoint of lowering resistance (in particular, a viewpoint of making the resistance of a lead part small), 20 nm or more is preferable, 40 nm or more is more preferable, 50 nm or more more preferably. On the other hand, the thickness of the metal thin film 10 is preferably 500 nm or less, more preferably 300 nm or less, and still more preferably 250 nm or less from the viewpoint of shortening the film formation time and improving the patterning accuracy.

When the metal thin film 10 is a nickel thin film or a nickel alloy thin film, the specific resistance at a temperature of 25°C ^{is preferably 1.6 × 10 -5} Ω·cm or ^{less, and more preferably 1.5 × 10 -5} Ω·cm or less. . From the viewpoint of reducing the resistance of the lead portion, the smaller the specific resistance of the metal thin film, the more preferable, and may be 1.2 × 10 ^-5 Ω·cm or less, or 1.0 × 10 ^-5 Ω·cm or less. The specific resistance of the metal thin film is small, the more preferable, it is difficult to reduce the specific resistance than the bulk of the nickel, in general, the specific resistance is more than 7.0 × 10 ^-6 Ω · ㎝.

3100 ppm/degreeC or more is preferable, and, as for the temperature coefficient of resistance (TCR) of the metal thin film 10, 3200 ppm/degreeC or more is more preferable. TCR is the rate of change of resistance with respect to temperature rise. Metals such as nickel and copper have a characteristic (positive characteristic) in which resistance increases linearly with temperature rise. TCR of the material having a positive temperature is to, from the resistance value R ₁ of the resistance value R _0, and the temperature T ₁ at the temperature T ₀ is calculated by the formula:

TCR = {(R ₁ ― R ₀ ) / R ₀ } / (T ₁ ― T ₀ )

In this specification, T ₀ = 25 ℃ and T ₁ Metal the average value of the TCR is calculated from the TCR and, T ₀ = 25 ℃ and T ₁ a resistance value at = 45 ℃ calculated from the resistance value in = 5 ℃ Thin film TCR.

As TCR is large, the change of resistance with respect to a temperature change is large, and the temperature measurement precision in a temperature sensor film improves. Therefore, it is preferable that the TCR of the metal thin film is larger, but it is difficult to make the TCR larger than that of the bulk metal, and the TCR of the metal thin film is generally 6000 ppm/°C or less.

As for the metal thin film 10, it is preferable that arithmetic mean roughness Ra1 calculated|required from the roughness curve of 1 micrometer in length is 2 nm or less. TCR tends to become large, so that Ra1 of the metal thin film 10 is small. With the increase of TCR, the temperature measurement precision of the temperature sensor film which patterned the metal thin film improves. Ra1 of the metal thin film 10 may be 1.5 nm or less, 1.2 nm or less, or 1.0 nm or less. Although it is not clear why the TCR increases as Ra1 is small, it is presumed that having characteristics close to bulk metal contributes to the increase in TCR because there are few irregularities at the nanoscale and the metal thin film has a dense structure. .

As for the metal thin film 10, it is preferable that the maximum height Rz2 calculated|required from the roughness curve of length 0.7mm is 150 nm or more. When Rz2 of a thin metal film is large, there exists a tendency for abrasion resistance to improve while slidability improves and running property of a conductive film improves. As for the metal thin film 10, it is preferable that arithmetic mean roughness Ra2 calculated|required from the roughness curve of length 0.7mm is about 0.5-25 nm, and its 1-20 nm is more preferable. When Ra2 is within the above range, unevenness is formed on the surface of the metal thin film 10, and it is possible to provide moderate sliding properties.

As described above, by making Ra1 of the surface of the metal thin film 10 small, TCR tends to become large, and by making Rz2 large, there exists a tendency for slidability to improve. When the metal thin film 10 is formed by a dry coating method such as a sputtering method, an uneven shape reflecting the surface shape of the resin film base material 50 is easily formed on the surface of the metal thin film 10 . Therefore, it is preferable that Ra1 of the resin film base material 50 is small and Rz2 is large.

In order to make the arithmetic mean roughness Ra1 in the nm scale small and the maximum height Rz2 in the μm scale large, as described above, the diameter in the film plane is submicron or It is preferable to form protrusions on the order of mu m. On the surface of the resin film 5, when a hard coat layer 6 containing fine particles having a particle diameter of submicron or micrometer order is formed, and a thin metal film 10 is formed thereon, Ra1 is kept small and Rz2 is can make it big Moreover, the improvement of mechanical strength, such as abrasion resistance, can be aimed at by forming a metal thin film on a hard-coat layer.

<Method of forming a thin metal film>

The method for forming the metal thin film is not particularly limited, and for example, a film formation method such as a sputtering method, a vacuum evaporation method, an electron beam evaporation method, a chemical vapor deposition method (CVD), a chemical solution deposition method (CBD), or a plating method can be adopted. Among these, the sputtering method is preferable at the point that a thin film excellent in film thickness uniformity can be formed into a film. It is preferable to form a metal thin film into a film, conveying a long resin film base material into a longitudinal direction continuously by the roll-to-roll method. By winding the resin film base material after forming a metal thin film into a film by the roll-to-roll method in roll shape, the wound body of the elongate conductive film is obtained. The length of an elongate conductive film is 10 m or more, for example, and it is excellent in productivity, so that length is large. The length of a long conductive film is not specifically limited, What is necessary is just to set suitably according to the allowable weight and diameter (winding diameter) of a winding mount, and is generally 10,000 m or less.

The sputtering method is suitable for formation of the metal thin film by roll-to-roll. The productivity of a conductive film becomes high by performing film-forming, using a roll-to-roll sputtering apparatus, driving a long resin film base material continuously in a longitudinal direction. In addition, as described above, when the metal thin film has a predetermined surface shape, the slip property and blocking resistance of the conductive film are increased, and the occurrence of scratches on the surface of the metal thin film and the winding shift when winding in a roll shape are suppressed. can do.

In the formation of a metal thin film by roll-to-roll sputtering, after loading a roll-shaped film substrate in the sputtering device, before starting sputtering film formation, the inside of the sputtering device is evacuated to an atmosphere in which impurities such as organic gas generated from the film substrate are removed. It is preferable to do By removing the gas in the apparatus and in the film base material in advance, the mixing amount of the water|moisture content with respect to the metal thin film 10, organic gas, etc. can be reduced. The vacuum degree (reached vacuum degree) in the sputtering apparatus before the start of sputtering film formation is, for example, 1 × 10 ^-1 Pa or less, preferably 5 × 10 ^-2 Pa or less, more preferably ^{1 × 10 -2 Pa or less,} 5 x 10 ^-3 Pa or less is more preferable.

The sputtering film formation of a metal thin film uses a metal target, and film-forming is performed, introduce|transducing inert gas, such as argon. For example, when a nickel thin film is formed as the metal thin film 10, a metallic Ni target is used. Although the film-forming conditions of a metal thin film are not specifically limited, The film-forming conditions are preferably selected so that mixing of impurities into the metal thin film resulting from moisture from a film base material, organic gas, etc. may be reduced. As a method of reducing the incorporation of impurities into the metal thin film, (1) as described above, the film substrate is treated under vacuum before sputter film formation to remove moisture, organic gas, and the like in the film substrate; (2) reducing the damage to the film substrate at the time of sputtering film formation; (3) Forming a base layer on a film base material, blocking the water|moisture content, organic gas, etc. from a film base material, etc. are mentioned.

As a method of reducing the damage to the film base material at the time of sputtering film formation, making the board|substrate temperature at the time of film-forming low, making a discharge power density low, etc. are mentioned. 200 degrees C or less is preferable, as for the board|substrate temperature, 150 degrees C or less is more preferable, and 120 degrees C or less is still more preferable. On the other hand, from the viewpoint of preventing embrittlement of the film substrate, the substrate temperature is preferably 0°C or higher. From a viewpoint of suppressing the damage to a film base material while stabilizing plasma discharge, 1-15 W/cm<2> is preferable and, as for the discharge power density, 2-10 W/cm<2> is more preferable.

＜Underground Floor＞

As shown in FIG. 2 , the conductive film may include a base layer 20 between the resin film base material 50 and the metal thin film 10 . By forming the base layer 20 on the resin film substrate 50 and forming the metal thin film 10 thereon, plasma damage to the resin film substrate 50 at the time of forming the metal thin film 10 can be suppressed. have. Moreover, by forming the base layer 20, water|moisture content, organic gas, etc. which generate|occur|produce from the resin film base material 50 can be interrupted|blocked, and mixing of the impurity with respect to the metal thin film 10 can be suppressed.

From a viewpoint of suppressing mixing of the organic gas with respect to a metal thin film, it is preferable that the base layer 20 is an inorganic material. The underlayer 20 may be conductive or insulating. In the case where the underlayer 20 is an electrically conductive inorganic material (inorganic conductor), the underlayer 20 may be patterned together with the metal thin film 10 at the time of manufacturing the temperature sensor film. When the underlayer 20 is an insulating inorganic material (inorganic dielectric), the underlayer 20 may or may not be patterned.

As inorganic materials, 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, Cd, etc. metal element or half and metal elements, and alloys, nitrides, oxides, carbides, and nitrides thereof. As the material of the base layer, silicon or silicon oxide is preferable from the viewpoints of excellent adhesion to both the resin film substrate and the thin metal film such as nickel, and the high effect of suppressing impurities in the metal thin film. As the underlayer, a silicon oxide layer may be formed on the silicon layer.

The underlayer may include a plurality of layers. For example, an inorganic dielectric may be formed on an inorganic conductor as a base layer, and a metal thin film may be formed thereon. In this aspect, since the dielectric layer is in contact with the metal thin film, it is not necessary to pattern the underlayer 20 at the time of manufacturing the temperature sensor film.

The thickness of the underlayer is not particularly limited. From the viewpoint of reducing plasma damage to the film substrate and enhancing the blocking effect of outgas from the film substrate, the thickness of the underlayer is preferably 1 nm or more, more preferably 3 nm or more, and furthermore 5 nm or more. desirable. From a viewpoint of productivity improvement or material cost reduction, 200 nm or less is preferable and, as for the thickness of a base layer, 100 nm or less is more preferable. When the base layer 20 consists of multiple layers, it is preferable that the total thickness is the said range.

The formation method of the base layer 20 is not specifically limited, Both dry coating and wet coating are employable. When forming the metal thin film by the sputtering method, it is preferable to also form the underlayer 20 by the sputtering method from a viewpoint of productivity.

[Temperature Sensor Film]

By patterning the metal thin film 10 of the conductive film, a temperature sensor film is formed. As shown in FIG. 3 , in the temperature sensor film, the metal thin film includes a lead portion 11 formed in a wiring shape, and a resistance thermometer 12 connected to one end of the lead portion 11 . The other end of the lead part 11 is connected to the connector 19 .

The resistance thermometer 12 is a region acting as a temperature sensor, and temperature is measured by applying a voltage to the resistance thermometer 12 through the lead 11 and calculating the temperature from the resistance value. By forming a plurality of resistance thermometers on the surface of the temperature sensor film 110 , temperatures at a plurality of points can be simultaneously measured. For example, in the form shown in FIG. 3, the thermometer 12 is formed in five points|pieces in a plane.

Fig. 4A is an enlarged view of the vicinity of a resistance thermometer in a two-wire temperature sensor. The resistance thermometer 12 is formed by sensor wirings 122 and 123 in which a thin metal film is patterned in a thin wire shape. In the sensor wiring, a plurality of vertical electrodes 122 are connected at their ends through horizontal wirings 123 to form a hairpin-shaped bent portion, and have a pattern of a wavy shape.

As the line width of the thin wire forming the pattern shape of the resistance thermometer 12 is small (the cross-sectional area is small) and the line length from one end 121a to the other end 121b of the sensor wiring of the resistance temperature measurement unit 12 is large, 2 Since the resistance between points is large and the amount of resistance change accompanying a temperature change is also large, the temperature measurement precision improves. By setting the wiring pattern in the shape of a cross-section as shown in Fig. 4, the area of the resistance thermometer 12 is small, and the length of the sensor wiring (line length from one end 121a to the other end 121b) can be increased. have. In addition, the pattern shape of the sensor wiring of a temperature measuring part is not limited to the form as shown in FIG. 4, Pattern shapes, such as a spiral shape, may be sufficient.

The line width of the sensor wiring 122 (vertical wiring) and the distance (space width) between adjacent wirings may be set according to the patterning precision of photolithography. A line width and a space width are generally about 1-150 micrometers. From a viewpoint of preventing disconnection of sensor wiring, 3 micrometers or more are preferable and, as for a line|wire width, 5 micrometers or more are more preferable. From the viewpoint of increasing the resistance change and improving the temperature measurement accuracy, the line width is preferably 100 µm or less, and more preferably 70 µm or less. From the same viewpoint, the space width is preferably 3 to 100 µm, more preferably 5 to 70 µm.

Both ends 121a and 121b of the sensor wiring of the resistance thermometer 12 are connected to one end of the lead portions 11a and 11b, respectively. The two lead portions 11a and 11b are opposite to each other with a slight gap therebetween, and are formed in an elongated pattern shape, and the other end of the lead portion is connected to the connector 19 . The lead portion is formed to be wider than the sensor wiring of the resistance thermometer 12 in order to ensure sufficient current capacity. The width of the lead portions 11a and 11b is, for example, about 0.5 to 10 mm. The line width of the lead portion is preferably 3 times or more, more preferably 5 times or more, still more preferably 10 times or more of the line width of the sensor wiring 122 of the resistance thermometer 12 .

The connector 19 is provided with a plurality of terminals, and the plurality of lead portions are respectively connected to different terminals. The connector 19 is connected to an external circuit, and by applying a voltage between the lead part 11a and the lead part 11b, the lead part 11a, the thermometer 12 and the lead part 11b are connected to each other. current flows A resistance value is calculated from a current value when a predetermined voltage is applied or an applied voltage when a voltage is applied so that the current becomes a predetermined value. Based on the relational expression between the obtained resistance value and the temperature calculated|required beforehand, or the table etc. which recorded the relationship between a resistance value and temperature, temperature is computed from a resistance value.

The resistance value obtained here includes the resistance of the lead part 11a and the lead part 11b in addition to the resistance of the thermometer 12, but the resistance of the thermometer 12 is the lead part 11a , 11b), the measured value may be regarded as the resistance of the resistance thermometer 12 since it is sufficiently large compared to the resistance of the . Moreover, from a viewpoint of reducing the influence by the resistance of a lead part, it is good also considering a lead part as a 4-wire type.

Fig. 4B is an enlarged view of the vicinity of a resistance thermometer in a four-wire temperature sensor. The pattern shape of the resistance thermometer 12 is the same as that of FIG. 4A. In the four-wire type, four lead portions 11a1, 11a2, 11b1, 11b2 are connected to one resistance thermometer 12. The lead portions 11a1 and 11b1 are voltage measurement leads, and the lead portions 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 resistance thermometer 12, and the voltage measurement lead 11b1 and the current measurement lead 11b2 ) is connected to the other end 121b of the sensor wiring of the resistance thermometer 12 . In the 4-wire type, since the resistance value of only the resistance thermometer 12 can be measured excluding the resistance of the lead, measurement with less error becomes possible. In addition to the 2-wire type and the 4-wire type, a 3-wire type may be employed.

The patterning method of the metal thin film is not specifically limited. Since patterning is easy and precision is high, it is preferable to perform patterning by the photolithographic method. In photolithography, an etching resist corresponding to the shape of the lead portion and the temperature resistance portion is formed on the surface of the metal thin film, and the metal thin film in the region where the etching resist is not formed is removed by wet etching, and then the etching resist is removed. peel off Patterning of the metal thin film can also be performed by dry etching such as laser processing.

In the above embodiment, the metal thin film 10 is formed on the resin film base material 50 by a sputtering method or the like, and the metal thin film is patterned to form a plurality of leads and a thermometer in the surface of the substrate. . A temperature sensor element is obtained by connecting the connector 19 to the edge part of the lead part 11 of this temperature sensor film. In this embodiment, a lead portion is connected to a plurality of resistance thermometers, and the plurality of lead portions may be connected to one connector 19 . Therefore, it is possible to simply form a temperature sensor element capable of measuring the temperature of a plurality of points in the plane.

In said embodiment, although the metal thin film was formed on one main surface of a film base material, you may form a metal thin film in both surfaces of a film base material. When forming a thin metal film on both surfaces of a film base material, a film base material may be equipped with a hard-coat layer on single side|surface or both surfaces.

The connection method of the lead part of a temperature sensor film and an external circuit is not limited to the form via a connector. For example, on the temperature sensor film, a controller for measuring resistance by applying a voltage to the lead portion may be provided. Moreover, you may connect the lead part and the lead wiring from an external circuit by soldering etc. without interposing a connector.

The temperature sensor film has a simple configuration in which a thin film is formed on a film substrate, is excellent in productivity, is easy to process, and can be applied to a curved surface. Moreover, since the TCR of the metal thin film is large, it is possible to realize temperature measurement with higher accuracy. Moreover, in embodiment of this invention, since the metal thin film has a predetermined|prescribed surface shape, it is excellent in the slidability of a film, and the improvement of the productive efficiency and yield of a temperature sensor film can be anticipated.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[Example 1]

A roll of 150 µm-thick polyethylene terephthalate (PET) film (“Lumira 149UNS” manufactured by Toray Industries) is set in a roll-to-roll sputtering device, and exhausted until the ^{achieved vacuum degree becomes 5×10 -3 Pa in the sputtering device} After that, argon was introduced, DC sputtering film formation was performed under the conditions of a substrate temperature of 40° C., a pressure of 0.3 Pa, and a power density of 5.0 W/cm 2 to prepare a conductive film having a Ni thin film having a thickness of 70 nm on a PET film did. A metallic nickel target was used for formation of the Ni layer.

[Example 2]

Sputter film formation was carried out in the same manner as in Example 1 except that the film substrate was changed to a polyimide (PI) film having a thickness of 38 µm (“Kapton 150EN” manufactured by Toray DuPont), and a Ni thin film was formed on the PI film. The provided conductive film was manufactured.

[Example 3]

Containing crosslinked polymethyl methacrylate particles having an average particle diameter of 1.5 µm (“Tech Polymer SSX-101” manufactured by Sekisui Chemical Industry Co., Ltd.) and UV-curable urethane acrylate resin (“Aika Itron” manufactured by Aika Industries), methyliso A coating composition using butyl ketone as a solvent was prepared. The amount of the particles in the composition was 0.2 parts by weight with respect to 100 parts by weight of the binder resin. This composition was apply|coated to the surface of the PET film used in Example 1, and it dried at 100 degreeC for 1 minute. Then, it hardened by ultraviolet irradiation and formed the 1.2-micrometer-thick hard-coat layer which has the surface uneven|corrugated structure by microparticles|fine-particles. Using this hard coat film as a base material, sputtering film-forming was performed similarly to Example 1, and the conductive film provided with Ni thin film on the hard-coat layer formation surface of PET film was manufactured.

[Comparative Example 1]

The particles in the coating composition were changed to silica particles having an average particle diameter of 30 nm ("CSZ9281" manufactured by CIK Nanotech), and the amount of the particles in the composition was changed to 15 parts by weight with respect to 100 parts by weight of the binder resin. Other than that, it carried out similarly to Example 3, the hard-coat layer was formed on PET film, and the electrically conductive film provided with Ni thin film on the hard-coat layer formation surface was manufactured.

[Comparative Example 2]

A hard coat layer was formed on the PET film in the same manner as in Example 3 except that a coating composition containing no particles was used, and a conductive film having a Ni thin film on the hard coat layer formation surface was prepared.

[evaluation]

<Measurement of surface shape of 1 µm square>

Using an atomic force microscope ("Dimension3100" manufactured by Bruker), the three-dimensional surface shape was measured according to the following conditions, the roughness curve of 1 µm in length was extracted, and the arithmetic mean roughness Ra1 was calculated according to JIS B0601.

Controller: NanoscopeV

Measuring mode: tapping mode

Cantilever: Si single crystal

Measurement field: 1 μm × 1 μm

<Measurement of surface shape of 0.7 mm square>

A roughness curve with a length of 0.7 mm is extracted from the three-dimensional surface shape obtained by measuring with a coherence scanning interferometer (Zygo NewView 7300) under the following conditions, and according to JIS B0601, arithmetic mean roughness Ra2, and maximum height Rz2 was calculated.

Objective lens: 10x, zoom lens 1x

Measurement field of view: 0.7 mm × 0.7 mm

Removed: None

Filter: High Pass

Filter Type: Gauss Spline

Low wavelength : 300 ㎛

Remove spikes: on

Spike Height (xRMS): 2.5

<temperature coefficient of resistance>

(Production of temperature sensor film)

The conductive film was cut to a size of 10 mm x 200 mm, and by laser patterning, the nickel layer was patterned into a stripe shape with a line width of 30 µm to form a resistance thermometer having a shape shown in Fig. 4A. At the time of patterning, the length of the pattern was adjusted so that the total wiring resistance was about 10 kΩ and the resistance of the resistance thermometer was 30 times the resistance of the lead, to prepare a temperature sensor film.

(Measurement of temperature coefficient of resistance)

With a small heating and cooling oven, the temperature resistance part of the temperature sensor film was made into 5 degreeC, 25 degreeC, and 45 degreeC. The two-terminal resistance at each temperature was measured by connecting one front-end|tip and the other front-end|tip of a lead part to a tester, flowing a constant current, and reading a voltage. The average value of TCR calculated from the resistance value of 5 degreeC and 25 degreeC, and TCR calculated from the resistance value of 25 degreeC and 45 degreeC was made into TCR of the nickel layer.

<blocking resistance>

A film with a smooth surface (“ZEONOR Film ZF-16” manufactured by Nippon Zeon) was pressed with acupressure on the Ni thin film formation surface of the conductive film, and the blocking state between the films was visually observed, and evaluated according to the following criteria. did.

○: Blocking did not occur immediately after crimping

△: Blocking occurred immediately after crimping, but blocking was resolved with the lapse of time

×: Blocking occurred immediately after compression, and blocking was not resolved even after time elapsed

Table 1 shows the surface roughness of the film base material before formation of the Ni thin film, the surface roughness of the Ni thin film of the conductive film, and the characteristics (TCR and blocking resistance) of the conductive film.

In Examples and Comparative Examples, the larger Ra1 of the film base material, the larger Ra1 of the Ni thin film, and the smaller Ra1, the larger the TCR tended to be. Moreover, the tendency for blocking resistance to improve was seen, so that Rz2 of a Ni thin film was large, so that Rz2 of a film base material was large, and Rz2 was large.

Comparing Example 1 using a film base material in which a hard coat layer is not formed and Comparative Example 2 using a film base material in which a hard coat layer not containing particles is formed, in Comparative Example 2, a hard coat layer is formed By this, the surface of a film base material was smoothed and TCR was improved, but since Rz2 was small, blocking resistance was falling. In Comparative Example 1 in which a Ni thin film was formed on a hard coat layer containing fine particles on the order of nm, Ra1 was larger than in Example 1, and TCR was lowered with this.

In Example 3 in which the Ni thin film was formed on the hard coat layer containing microparticles of the order of micrometers, Ra1 was smaller than in Example 1, and TCR was raised. In Example 3, since the particle diameter of the fine particles contained in the hard coat layer is large and the size of the projections by the particles is large, the arithmetic mean roughness Ra1 when the surface shape is viewed on the nm scale is smaller than in Example 1. I think. On the other hand, in Example 3, the maximum height Rz2 when viewed on a micrometer scale was large by the protrusion formed by the particle|grains, and the blocking resistance was improved by this.

In Example 2 in which the Ni thin film was formed without forming a hard-coat layer on the polyimide film base material, similarly to Example 3, high TCR and favorable blocking resistance were shown. It turns out that TCR is large and the electrically conductive film excellent in blocking resistance can be formed by adjusting the surface shape of a film base material from these results. By forming a hard coat layer containing particles with a large particle diameter on the resin film, in addition to being able to achieve both improvement in TCR and improvement in blocking resistance, the surface hardness is increased and the scratch resistance of the metal thin film can be improved. have.

50: film substrate
5: resin film
6: hard coat layer
20: lower layer
10: metal thin film
11: lead part
12: resistance thermometer
122, 123: sensor wiring
19: connector
101, 102: conductive film
110: temperature sensor film

Claims (11)

A metal thin film is provided on one main surface of the resin film substrate,
An arithmetic mean roughness Ra1 obtained from a roughness curve having a length of 1 μm on the surface of the metal thin film is 2 nm or less,
The conductive film for temperature sensors whose maximum height Rz2 calculated|required from the roughness curve of length 0.7mm of the said metal thin film surface is 150 nm or more. The method of claim 1,
The conductive film for a temperature sensor, wherein the temperature coefficient of resistance of the metal thin film is 3100 ppm/°C or more. 3. The method according to claim 1 or 2,
The resin film base material is provided with a hard coat layer on the surface of the resin film,
The conductive film for temperature sensors in which the said metal thin film is formed on the said hard-coat layer directly or via another layer. 4. The method of claim 3,
The conductive film for temperature sensors in which the said hard-coat layer contains microparticles|fine-particles. 5. The method according to any one of claims 1 to 4,
The thickness of the said metal thin film is 20-500 nm, The conductive film for temperature sensors. 6. The method according to any one of claims 1 to 5,
The conductive film for a temperature sensor, wherein the metal thin film is made of nickel or a nickel alloy. The electrically conductive film wound body by which the electrically conductive film in any one of Claims 1-6 is wound up in roll shape. A method of manufacturing the conductive film wound body according to claim 7, comprising:
The manufacturing method of the electrically conductive film winding body which forms the said metal thin film into a film by roll-to-roll sputtering, driving a long resin film base material in one direction. A metal thin film patterned on one surface of a resin film substrate is provided,
The metal thin film is patterned with a resistance thermometer used for temperature measurement and patterned into thin wires, and a lead part connected to the resistance temperature measurement unit and patterned with a line width larger than that of the resistance temperature resistance unit,
An arithmetic mean roughness Ra1 obtained from a roughness curve having a length of 1 μm on the surface of the metal thin film is 2 nm or less,
The maximum height Rz2 calculated|required from the roughness curve of length 0.7mm of the said metal thin film surface is 150 nm or more, The temperature sensor film. 10. The method of claim 9,
The resin film base material is provided with a hard coat layer on the surface of the resin film,
The temperature sensor film in which the said metal thin film is formed directly or via another layer on the said hard-coat layer. 11. The method of claim 10,
The temperature sensor film in which the said hard coat layer contains microparticles|fine-particles.

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