JP3325361B2 - Transparent planar heater and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display,
The present invention relates to a transparent surface heating element used for a window portion of a refrigerated showcase or the like.

[0002]

2. Description of the Related Art Conventionally, a frozen or refrigerated showcase has a transparent conductive film formed on a glass surface and a predetermined electric power is applied thereto to heat a window surface in order to prevent dew condensation on the glass surface. Was used. In recent years, the demand for liquid crystal display elements has been increasing, and in the case of use in cold regions, there has been a problem that the operation of liquid crystal has been slowed down. The nature has increased. As a method of forming a transparent sheet heater, a method in which an electrode is formed with a conductive paint such as a silver paste on a transparent conductive film formed on a transparent substrate such as a glass or a plastic film, or the reliability as an electrode is improved. Therefore, a metal foil sandwiched with a conductive paint has been used. However, an electrode formed of a conductive paint has a large resistance of the paint itself and a high contact resistance between the formed electrode and the transparent conductive film. Electricity non-uniformity occurs, and therefore, temperature unevenness is likely to occur in the transparent planar heater. Therefore, there has been a problem that the temperature of the entire transparent surface does not rise, and a problem that the current concentrates in the vicinity of the electrode contact and burns the transparent planar heater. As a method of improving this, there is a method in which a copper foil is inserted between conductive paints and laminated to form an electrode. By using this electrode forming method, the occurrence of uneven current distribution is reduced. In addition, the manufacturing process for performing the process is complicated, the workability is poor, and the cost of the product is increased.

[0003] The present inventors are studying forming a metal electrode of a transparent planar heater by a plating method. When forming the metal electrode on the transparent conductive film, immersion treatment is performed in advance with an aqueous acid solution, and an acidic plating solution is used. However, it has also been found that an oxide thin film such as indium oxide dissolves by the immersion treatment and has a problem that the surface resistance of the transparent conductive film changes. Conventionally known transparent conductive films include (1) metal thin films such as gold, palladium, silver, and copper (2) compound semiconductors such as indium oxide and tin oxide (3) metal thin films such as gold, silver, and palladium Titanium oxide,
One sandwiched between oxide thin films such as indium oxide and zirconium oxide can be used.

As for the above (1), an excellent product satisfying both sufficient visible light transmittance and conductivity cannot be obtained. The compound semiconductor of the above (2) can be formed by a thin film forming method in a vacuum such as a vacuum evaporation method, a sputtering method, an ion plating method, or a thin film forming method such as a sol-gel method. In order to obtain a thin, transparent conductive film having a small surface resistance, a film thickness of about several hundreds of nm is usually required, and as a result, the production cost of the film increases. A typical configuration of the laminate in which the metal thin film of the above (3) is sandwiched between oxide thin film layers is titanium oxide / silver /
A laminate having a sandwich structure such as titanium oxide or indium oxide / silver / indium oxide has been used. Those using a silver thin film or a thin film composed of silver and gold as the metal thin film are also excellent in transparency and conductivity in the visible light region, and have been used as preferred.

[0005] For an oxide thin film such as titanium oxide, methods such as sputtering, ion plating, vacuum deposition, and wet coating can be used. However, when the laminate is formed in a vacuum such as sputtering or ion plating, the silver thin film is easily oxidized by oxygen ions or the like activated by electric discharge. When a thin film layer is provided, or when a silver thin film is formed or an oxide thin film layer is formed on the silver thin film, a reducing gas such as hydrogen is introduced to form a laminate so that silver is not oxidized. I was In the case of forming a laminate using wet coating, after forming an oxide thin film layer by hydrolysis, a metal thin film is formed by vacuum evaporation or sputtering, and the oxide thin film layer is further hydrolyzed. At this time, by forming sulfides or the like on the silver thin film in advance or adjusting the pH during hydrolysis to a predetermined range, the silver thin film is deteriorated by hydrogen ions or impurities. Had been tried to prevent it. In any of the methods, the adjustment of the conditions during film formation is complicated, and the characteristics of the obtained film are liable to fluctuate, and the laminates manufactured by these methods can perform better depending on environmental conditions such as heat, light, oxygen, and water. There is a problem that the decrease is easily caused.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the durability of a transparent copper conductive film and the method of forming a transparent conductive film and an electrode on the transparent conductive film. And the productivity of the production of a transparent sheet heater.

[0007]

That is, the present invention provides at least a transparent high refractive index thin film layer (C), a first metal thin film layer (A), and a second metal A thin film layer (B) is sequentially laminated from the substrate, and CBABC, C
A transparent sheet heater comprising a transparent conductive substrate on which a transparent conductive film formed in the order of ABC or CBAC is formed, wherein a metal electrode is provided on the transparent conductive film so as to secure a transparent region. The first metal thin film layer (A) is a transparent sheet heater selected from the group consisting of silver, silver-gold alloy, silver-copper alloy, silver-palladium alloy, and silver-platinum alloy; The second metal thin film layer (B) is a transparent sheet heater made of a single metal or an alloy selected from the group consisting of titanium, zirconium, tantalum, vanadium, and aluminum. C) is a transparent sheet heater made of silicon nitride. At least one transparent high-refractive-index thin film layer (C), a first metal thin film layer (A), and a second metal thin film layer (B) are sequentially laminated on one main surface of the transparent substrate from the substrate. , CB
When forming a metal electrode on a transparent conductive substrate on which a transparent conductive film formed in the order of ABC, CABC, or CBAC is formed, a transparent region is secured and a hardening type is formed so as to expose the metal electrode formation region. Is a method for manufacturing a transparent sheet heater characterized by forming a metal electrode by electroplating on the metal electrode formation region, and curing the resist resin by applying a resist resin, and the metal electrode formed by electroplating is copper, Nickel, palladium, chrome, gold,
A method for producing a transparent sheet heater comprising at least one metal composed of silver, zinc, tin, lead or a laminate thereof, and a metal sheet having a thickness of 1 μm to 42 μm. It is a manufacturing method.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
An example of the embodiment will be described. First, the accompanying drawings will be described. FIG. 1 is a cross-sectional view of a configuration showing a preferred example of a transparent planar heater of the present invention. FIGS. 2 and 3 show a preferred example of a transparent conductive film used in the present invention. FIG. 4 is a cross-sectional view of the configuration shown, and FIG. 4 is a cross-sectional view of the configuration showing a comparative example.
Here, 10 is a transparent substrate, 20 is a transparent high refractive index thin film layer (C), 30 is a first metal thin film layer (A), 40 is a second metal thin film layer (B), 50 is a metal electrode, 60 Is a protective layer, 7
0 is a transparent protective layer, and 80 is a conductive paint.

More specifically, the transparent conductive substrate of the present invention is transparent on one side of the transparent substrate 10 in a visible light region of 400 nm to 800 nm as shown in FIG. 2 or FIG. C) The transparent high-refractive-index thin film layer 20 is silver or an alloy thin film containing silver as a main component (A).
The first metal thin film layer 30 is a single metal or alloy thin film of titanium, zirconium, tantalum, vanadium, and aluminum (B), and a second metal thin film layer 40 is sequentially laminated.

As shown in FIG. 1, the transparent sheet heater according to the present invention is provided with a metal electrode on a transparent conductive film formed on a transparent substrate 10, more precisely, on an outermost transparent high refractive index thin film layer 20. After applying and curing a resist resin on a portion other than the formation region to form a protective layer, a metal electrode is formed by an electroplating method. More preferably, it is a transparent sheet heater in which a transparent protective layer made of a resin or a film is laminated on the metal electrode and the protective layer for mechanical and chemical protection. Thereby, without damaging the transparent conductive film,
Since the metal electrode can be formed substantially directly on the transparent conductive film, an effect of improving the electrical connection between the metal electrode and the transparent conductive film and improving the performance can be obtained.

Further, in the method for manufacturing a transparent sheet heater according to the present invention, at least the transparent high refractive index thin film layer (C), the first metal thin film layer (A), and the second Metal thin film layer (B) is sequentially laminated from the substrate,
When forming a metal electrode on a transparent conductive substrate on which a transparent conductive film formed in the order of BC, CABC or CBAC is formed, a hardening type resist resin is used to secure a transparent region and expose the metal electrode formation region. Is applied and cured,
A transparent sheet heater characterized in that a metal electrode having a thickness of preferably about 1 μm to 42 μm is formed on the metal electrode formation region by electroplating.
Thus, while providing a metal electrode having good adhesion on the transparent conductive film, and using a resist resin such as an acrylic resin that is cured by irradiating ultraviolet rays or the like as a protective layer, the position of the metal electrode formation region is determined at the same time. In addition, it is possible to exhibit the function and effect that is also used as the protective layer of the transparent conductive film. Thus, there is provided a method for manufacturing a transparent sheet heater with markedly improved work efficiency and reliability.

The transparent conductive film used in the present invention has a thickness of 400 nm to 800 nm on one main surface of a transparent substrate 10 such as a glass or plastic film as shown in FIG. 2 or FIG.
A transparent high-refractive-index thin film layer 20 which is transparent in the visible light region, a first metal thin film layer 30 made of silver or an alloy mainly composed of silver as described in detail below; The second metal thin film layer 40 which is a single metal or alloy thin film of titanium, zirconium, tantalum, vanadium, aluminum or the like is sequentially laminated.

The transparent high refractive index thin film layer 2 used in the present invention
The term “0” means that the material has a light transmittance of at least 70% or more, preferably 80% or more in a visible light region of 400 nm to 800 nm, and has a refractive index of 1.6 or more, for example, nitride. Then, aluminum nitride, boron nitride, gallium nitride, silicon nitride, indium nitride, and the like are used, and silicon nitride is particularly preferably used. Note that a thin film layer of copper, nickel, palladium, gold, or the like may be further provided on the outermost transparent high refractive index thin film layer in a range of 0.5 to 5 nm. It is understood by those skilled in the art that plating can be easily performed.

As the first metal thin film layer, a metal having excellent electric conductivity is preferably used.
A gold alloy, a silver-platinum alloy, a silver-copper alloy, a silver-palladium alloy, or the like is preferably used. The thickness of the first metal thin film layer is determined in a range where transparency is obtained while maintaining electrical conductivity, and specifically, is preferably in a range of 5 to 30 nm,
More preferably, it is 7 to 20 nm. The amount of alloying elements added to silver is, for example, preferably 3 to 30%, more preferably about 5 to 15%. Of course, those outside this range can also be used, but if it is less than 3%, the silver layer will turn yellow in an acidic solution, and if it exceeds 30%, the light transmittance and conductivity will be reduced. Is preferred. The first metal thin film layer may contain tungsten, chromium, aluminum, titanium, tantalum, nickel or the like to the extent that the performance is not impaired.

The second metal thin film layer is preferably a stable metal such as an oxide or a nitride, that is, a material having a large negative free energy of standard formation of an oxide or a nitride, such as titanium, aluminum, zirconium, tantalum, or copper. ,nickel,
Chromium, iron, manganese, tungsten, vanadium and the like can be mentioned. Among them, titanium, zirconium, vanadium, tantalum and aluminum are particularly preferably used. The thickness of the second metal thin film layer is preferably in a range where sufficient adhesion between the first metal thin film layer and the high transparent refractive index thin film layer is obtained and the transparency is not impaired. More specifically, the thickness is about 0.4 nm to 5 nm. If the thickness is less than 0.4 nm, sufficient adhesion cannot be obtained, and if it exceeds 5 nm, the transparency is reduced. However, a thin or thick material outside this range can be used depending on the purpose. For example, in the case of an application where transparency may be sacrificed to some extent, it does not prevent the use of a metal thin film layer of 5 nm or more. In addition, the second metal thin film layer may contain impurities that do not impair the performance. It is surprising that the adhesion is dramatically improved even when the thickness of the second metal thin film layer is only 0.4 nm.

The thickness of the transparent high-refractive-index thin film layer is adjusted so as to maximize the transmittance of visible light or to maximize the transmittance of light having a wavelength of 550 nm.
Is more preferable, and more preferably, it is 30 to 50 nm. If the thickness of the transparent high refractive index thin film layer is too thick,
The wavelength at which the light transmittance becomes maximum is longer than 550 nm. Conversely, if the wavelength is too thin, the wavelength at which the light transmittance becomes maximum is 5 nm.
It becomes shorter than 50 nm.

For the production of the metal thin film layer, for example, a sputtering method, a vacuum evaporation method, and an ion plating method are preferably used. Here, the sputtering method is a general term for DC magnetron sputtering, rf magnetron sputtering, ion beam sputtering, and the like. In the sputtering method, for example, when a silver thin film is formed, an argon gas is used as a sputtering gas using a silver target. When producing a silver-gold alloy thin film, a silver-gold alloy target is used. A similar method may be used for producing a silver-platinum alloy, a silver-copper alloy, or a silver-palladium alloy thin film. When producing an alloy thin film by a vacuum evaporation method, a binary evaporation method is preferably used. Although a wet plating method can be used to form the metal thin film layer, a film forming method using a vacuum such as a sputtering method or a vacuum evaporation method is preferable from the viewpoint of controlling the film thickness.

As a method for producing the transparent high-refractive-index thin film layer, for example, a wet method such as a sol-gel method can be used, but a sputtering method or an ion plating method is preferably used like the metal thin film layer. In the sputtering method, when the insulator is a target, the rf magnetron sputtering method is preferably used. For example, when manufacturing an indium oxide thin film, using a sputtering method, using a metal indium target, using a reactive sputtering method using argon as a sputtering gas and oxygen as a reactive gas, or using a target of indium oxide. An ordinary sputtering method using argon as a sputtering gas is used. When producing silicon nitride, reactive sputtering in which a silicon target is sputtered with argon and nitrogen gas, or
An ordinary sputtering method for sputtering a silicon nitride target with an argon gas may be used. In the ion plating method, silicon can be evaporated in nitrogen plasma to obtain a silicon nitride film. In addition, it goes without saying that a desired film can be obtained by the activated reactive vapor deposition method or the plasma CVD method. In the plasma CVD method, a silicon nitride thin film can be formed using, for example, silane and nitrogen, silane and ammonia, silazane and nitrogen, silazane and ammonia, and the like.

Further, the silicon nitride film according to the present invention is formed of silicon / silicon.
Nitrogen is preferably in the range of 0.75 to 1.2, and may be amorphous or crystalline as measured by X-ray diffraction. Also, in indium oxide, titanium oxide, boron nitride, aluminum nitride, and the like, the composition may be different from the stoichiometric composition, and the crystallinity may be different depending on the manufacturing method. Is understood by those skilled in the art, and the point is that it is important that a thin film layer having an appropriate refractive index and transparency be obtained.

For measuring the thickness of the metal thin film layer or the transparent high refractive index thin film layer, there are a stylus roughness meter, a repetitive reflection interferometer, a microbalance, a crystal oscillator method, and the like. Since the film thickness can be measured in the film, it is suitable for obtaining a desired film thickness. In addition, the conditions for film formation are determined in advance,
There is also a method of forming a film on a test substrate, examining the relationship between the film formation time and the film thickness, and then controlling the film thickness by the film formation time. For example, when the film thickness of the thin film formed for M (seconds) is measured by a stylus roughness meter and is D (nm), d (n)
To obtain the film thickness of m), the film formation time T
(Seconds). That is, T = d × (M / D) (sec). For example, in a sputtering method, titanium
Assuming that a 100-nm titanium film is obtained when the film is formed for 0 seconds, the film is formed for 10 seconds to obtain a 1-nm titanium film under the same film forming conditions. When the film thickness is determined by the crystal oscillator method, if the decrease in the frequency of the crystal oscillator is F (Hz) when a film having a film thickness of D (nm) is produced, d (nm) is formed. Determines the film thickness when the frequency f (Hz) obtained by the following equation decreases. That is, f = d × (F / D). Here, D may be determined using a stylus roughness meter, a repetitive reflection interferometer, or the like. In the present invention, the film thickness is determined by such a method, and the thin film layer according to the present invention does not need to be a common-sense continuous film or continuous layer, for example, an island-like structure. It is also understood by those skilled in the art that it may have
It is pointed out in a compendium (for example, "Basic Technology of Thin Films" by Kanu Kanehara, published by the University of Tokyo, pages 89 to 94).

When a transparent high refractive index thin film layer is formed on a polymer film substrate, corona discharge treatment, plasma discharge treatment, glow discharge treatment, reverse sputtering treatment, surface roughening treatment, Performing a chemical treatment or the like or applying a known undercoat can be appropriately performed. The configuration of a laminate formed of, for example, a maximum of five layers formed on the polymer film can be analyzed by an analysis method having an analysis capability in the depth direction. Specifically, Auger electron spectroscopy, X-ray photoelectron spectroscopy,
Secondary ion mass spectrometry, Rutherford backscattering, or the like can be used. In particular, since the laminate according to the present invention has a fine structure, Auger electron spectroscopy in which the resolution in the depth direction is improved by argon ion etching in combination with the Zarrah rotation method is preferably used.

The transparent substrate of the present invention has a thickness of 400 nm to 400 nm.
80% light transmittance in the visible light region of 800 nm
Above, more preferably 85% or more of the substrate, a transparent plastic film can be used in addition to glass, and a plastic film is preferable in terms of thinness, flexibility, impact resistance, continuous productivity, and the like. Used. Examples of the plastic used in the present invention include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides, polyethers, polysulfones, polyethersulfones (PES), Polycarbonate, polyarylate, polyetherimide, polyetheretherketone (PEE
K), a plastic film composed of a homopolymer such as polyimide, aramid or the like or a copolymer. The thickness of the plastic film used in the present invention is usually 5 μm to 500 μm, preferably 10 μm to 2 μm.
00 μm, more preferably 50 μm to 150 μm
m is appropriate.

The metal electrode of the present invention is formed by applying a transparent resist resin such as an ultraviolet curable acrylic resin or a thermosetting polyester resin to a portion of the transparent conductive film other than the metal electrode forming region to form a protective layer. It can be formed directly by electroplating. The protective layer used in the present invention preferably has a light transmittance at a wavelength of 550 nm after curing of at least 70% or more, more preferably 80% or more. The thickness of the protective layer is usually 1 μm to 100 μm, preferably 5 μm to 50 μm, more preferably 1 μm to 50 μm.
0 μm to 30 μm is appropriate. In the present invention, any metal that can be formed by plating can be used as the metal of the metal electrode, but from the viewpoint of electrical characteristics and durability, a single metal such as copper, silver, nickel, chromium, tin, and lead is used. Alternatively, it is preferable to be composed of a single layer or a laminate of an alloy. As a plating method, electroless plating can be applied, but electroplating is preferably used from the viewpoint of productivity.

In order to chemically protect the metal electrode and the protective layer of the transparent sheet heater of the present invention, such as mechanically and preventing corrosion due to moisture, a transparent protective layer is formed so as to cover the metal electrode and the protective layer. May be further provided. 5 as a transparent protective layer
A light transmittance at a wavelength of 50 nm of at least 70% or more;
More preferably, 80% or more is desirable. As the transparent protective layer, a plastic film used as a transparent substrate may be laminated using an adhesive, or an organic material such as polyester, polyolefin, or acrylic resin, as well as a silicone hard coat agent, a silica sol agent, or the like. Can be applied as a protective layer. The thickness of the transparent protective layer used in the present invention is usually 1 μm to 200 μm, preferably 2 μm to 100 μm, more preferably 5 μm to
50 μm is appropriate. FIGS. 1 to 3 show examples of cross-sectional views as examples of preferred embodiments of the present invention. These are listed and described according to the order in which the respective thin film layers are formed. Another compound may be formed at the interface of each layer by, for example, inclusions or precipitates, or a certain layer may be converted to another compound, or in a case where it is a preferable form. Some things are natural. Hereinafter, an example of an embodiment of the present invention will be described with reference to examples.

[0025]

【Example】

Example 1 On a PET having a visible light transmittance of 89% and a thickness of 100 μm,
For example, according to FIG. 2, (C) silicon nitride (40 nm) and (B) titanium (1n) by DC magnetron sputtering.
m), (A) silver (12 nm), (B) titanium (1n
m) and (C) silicon nitride (40 nm) in this order to form a transparent conductive film on which a laminated film was formed. The transmittance of this transparent conductive film for light having a wavelength of 550 nm was 80.9%. 125mm (length) x 4mm
A UV-curable transparent resist resin is applied and cured so that the distance between both metal electrodes is 90 mm in size (width), and a protective layer is formed. A copper film having a thickness of 20 μm was formed in a plating bath. PET of 25μm thickness leaving the connector part of the metal electrode
The film was laminated on the metal electrode and the protective layer to form a transparent protective layer. The resistance between both metal electrodes of the formed transparent sheet heater was 4.4Ω. This transparent sheet heater is -2
When a power of 13 V and 3.3 A was supplied in a thermostat at 0 ° C., the surface temperature rose to 23 ° C. in one minute.

Example 2 (C) Silicon nitride (40 nm), (B) Titanium (1 nm), (A) Silver-gold on one principal surface of a 50 μm thick PES having a visible light transmittance of 88% by DC magnetron sputtering. Alloy layer (12 nm), (B) titanium (0.8 nm),
(C) Silicon nitride (40 nm) was sequentially laminated. The gold-silver alloy layer was formed using a target having a composition of silver-3 wt% gold alloy. The size of 35 mm (length) x 4 mm (width) is set so that the distance between both metal electrodes is 90 mm.
After applying and curing a V-curing type acrylic resin to form a protective layer, the coating layer was treated with a nickel sulfamate plating bath having a pH of 3.5.
A nickel film having a thickness of 0 μm was formed. An acrylic urethane-based UV-curable resin was applied and cured on the metal electrode and the protective layer except for the connector portion of the metal electrode to form a transparent protective layer. The resistance between both metal electrodes of the formed transparent sheet heater was 5.4Ω. -20 ° C
When a power of 12 V and 2.4 A was supplied in the constant temperature bath, the surface temperature rose to 21 ° C. in one minute.

Example 3 (C) Silicon nitride (35 nm), (B) Titanium (1n) were formed on the PET of Example 1 by DC magnetron sputtering.
m), (A) a silver-platinum alloy (12 nm), and (C) silicon nitride (35 nm) were sequentially laminated to form a transparent conductive film. The silver-platinum alloy layer was produced by sputtering a silver-5 wt% platinum target. The light transmittance of this film transparent conductive film is:
80.4%. 35mm (length) x 4mm (width)
A UV curable acrylic resin is applied and cured so that the distance between the two metal electrodes is 90 mm, and a protective layer is formed. Then, a nickel film having a thickness of 20 μm is formed in a pH 3.5 nickel sulfamate plating bath. did. An acrylic urethane UV-curable resin was applied and cured to leave a connector portion of the metal electrode to form a transparent protective layer. The resistance between both metal electrodes of the formed transparent sheet heater was 5.1Ω.
This transparent sheet heater is set to 12V in a -20 ° C constant temperature bath.
When 2.4 A power was applied, the surface temperature rose to 20 ° C. in one minute.

Example 4 Using the transparent conductive film prepared in Example 3, 35
A UV-curable acrylic resin was applied and cured so as to have a size of mm (length) × 4 mm (width) and a distance between both metal electrodes of 90 mm to form a protective layer. This was immersed in a sulfuric acid aqueous solution of pH 1 for 2 minutes to perform pretreatment. Then rinse with water,
After drying, solder plating was performed in an alkanolsulfonic acid bath. An acrylic urethane UV-curable resin was applied and cured to leave a connector portion of the metal electrode to form a transparent protective layer. The resistance between both metal electrodes of the formed transparent sheet heater was 5.0Ω. This transparent sheet heater is -2
When a power of 12 V and 2.4 A was supplied in a constant temperature bath at 0 ° C., the surface temperature rose to 20 ° C. in one minute. Next, a comparative example will be described.

Comparative Example 1 A transparent conductive film having the same size and the same configuration as in Example 1 was used as a transparent sheet heater base material, and the configuration shown in FIG. 4 was used. Was applied, and the conductor was fixed to form an electrode for a transparent sheet heater. When power was applied to this and a temperature rise test was performed, abnormal heat was generated between the electrode (conductive paint) of the transparent sheet heater and the transparent conductive film, and the transparent conductive film was burnt and disconnected. did.

Comparative Example 2 On one principal surface of PET similar to that of Example 1, D used in Example 2 was used.
(C) silicon nitride (40) by C magnetron sputtering
nm), (A) silver (10 nm), (C) silicon nitride (40
nm) were sequentially laminated to produce a transparent conductive film. An attempt was made to plate the obtained laminate with copper in a sulfuric acid-acidic copper sulfate solution at pH 3, but no plating layer was formed. After 2 minutes, the layer was taken out of the plating bath and the surface resistance was measured. As a result, electroplating could not be performed. Thus, the transparent conductive film is formed of at least the second metal layer thin film (B).
It must be understood that it must be configured to include

[0031]

As is clear from the above Examples and Comparative Examples, the present invention makes it possible to improve the production process and to produce a highly durable transparent sheet heater. In other words, it is an industrially useful invention that leads to cost reduction.

[Brief description of the drawings]

FIG. 1 is a diagram showing a layer configuration of a preferred example of a planar heater of the present invention.

FIG. 2 is a diagram showing a layer configuration of an example of a transparent conductive film according to the present invention.

FIG. 3 is a diagram showing a layer configuration of an example of a transparent conductive film according to the present invention.

FIG. 4 is a diagram showing a layer configuration of a planar heater of a comparative example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 transparent substrate 20 transparent high refractive index thin film layer 30 first metal thin film layer 40 second metal thin film layer 50 metal electrode 60 protective layer 70 transparent protective layer 80 conductive paint 90 conductive wire

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-57-1755 (JP, A) JP-A-5-174951 (JP, A) JP-A-5-23486 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) H05B 3/20 H05B 3/03 H01B 5/14 H05B 3/10 H05B 3/12

Claims (3)

(57) [Claims] At least one transparent high-refractive-index thin film layer (C), a first metal thin film layer (A), and a second metal thin film layer (B) are provided on one main surface of a transparent substrate. In a transparent conductive substrate on which a transparent conductive film formed in order of CBABC, CABC, or CBAC is formed, the first metal thin film layer (A) is formed of silver, a silver-gold alloy,
A layer having a thickness of 5 to 30 nm selected from the group consisting of a copper alloy, a silver-palladium alloy, and a silver-platinum alloy, wherein the second metal thin film layer (B) is made of titanium, zirconium, tantalum, vanadium, or aluminum; A layer having a thickness of 0.4 to 5 nm, which is a single metal or alloy selected from the group, and cured so as to secure a transparent region on the transparent conductive film and expose a metal electrode formation region. Applying and curing a resist resin of a mold, and electroplating the metal electrode forming region by copper, nickel, palladium, chromium, gold, silver, zinc, tin, at least one or more metals composed of lead or a laminate thereof. Wherein a metal electrode having a thickness of 1 μm to 42 μm is formed. 2. The transparent sheet heater according to claim 1, wherein the transparent high refractive index thin film layer (C) is silicon nitride. 3. The method for producing a transparent sheet heater according to claim 1.