JPH0523486U - Panel heater - Google Patents

Abstract

(57) [Summary] [Object] The present invention simplifies the process of forming electrodes on a transparent conductive film in the panel heater manufacturing process, and improves the productivity of the panel heater manufacturing. A panel heater in which a metal layer (3) is directly laminated on the transparent conductive film (2) formed on the transparent substrate (1) to form an electrode. According to the present invention, the manufacturing process of the panel heater, which has a complicated manufacturing process and poor workability in the conventional technology, is improved, and the reliability of the panel heater is also improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a panel heater used for a liquid crystal display device, a freezer, a refrigerated showcase, and the like.

[0002]

[Prior Art]

 Conventionally, frozen and refrigerated showcases have been used in which a transparent conductive film is formed on the glass surface in order to prevent condensation on the glass surface. In addition, in recent years, the demand for liquid crystal display elements has increased, but when used in cold regions, the operation of the liquid crystal may slow down, and the need for panel heaters for liquid crystal display elements has increased. .. Panel heaters are formed by forming electrodes with a conductive paint on a transparent conductive film formed on glass or a plastic film, or by sandwiching a metal foil with a conductive paint to improve reliability. What was done was used. Electrodes formed of conductive paint have high resistance of the paint itself and high contact resistance between the formed electrodes and the transparent conductive film. As a result, there was a problem in that the temperature of the panel heater was uneven and the temperature of the entire panel did not rise, and current concentration occurred in the area near the electrode contacts, causing burns in the panel heater. As an improvement plan for this, there is one in which a copper foil is inserted between conductive paints and laminated to form an electrode. This electrode forming method does not cause uneven conduction, but the manufacturing process is complicated and the workability is poor because the electrodes are formed.

[0003]

[Problems to be solved by the device]

 The process of forming electrodes on the transparent conductive film is simplified and the productivity of manufacturing panel heaters is improved.

[0004]

[Means for Solving the Problems]

 The present inventors have devised a panel heater having a structure as shown in FIG. 1 in order to solve the above problems. That is, a transparent electrode film 2 is formed by vapor-depositing In—Sn oxide (ITO) or the like on a transparent substrate 1 made of plastic, and a metal layer 3 is laminated on the transparent conductive film 2 with a space therebetween. It was used as an electrode for a panel heater. Further, a resin or film may be laminated as the protective film 6 for mechanical and chemical protection of the transparent conductive film 2 and the metal layer 3. The metal layer 3 can be formed by directly laminating nickel, copper, palladium, gold or the like on the transparent conductive film 2 by a dry plating method or a wet plating method. By forming the metal layers 3 on both ends of the transparent conductive film 2 in this manner, the process of forming the panel heater is simplified and the yield is greatly improved.

The transparent conductive film used in the present invention is one in which a compound semiconductor such as tin oxide or indium oxide is laminated on a transparent substrate such as a plastic film, and a metal thin film such as gold, silver, copper or palladium. A layered structure in which a metal thin film of gold, silver, copper, palladium, etc. and a high refractive index thin film of indium oxide, titanium oxide, etc. are laminated in a sandwich structure is used. A laminate having a structure of transparency and conductivity is desirable, and a preferable example of the laminate is a thin silver film sandwiched with indium oxide or ITO. At this time, from the viewpoint of preventing deterioration of the transparent conductive film due to energization, it is preferable that the silver thin film contains a metal such as gold, copper or palladium in a range not impairing conductivity and transparency.

The transparent substrate is preferably a plastic film from the viewpoint of flexibility, impact resistance, etc., and the light transmittance at a wavelength of 600 nm is preferably at least 70% or more, more preferably 80% or more.

Examples of preferred resins for the film material include homopolymers or copolymers of polyester, polyamide, polyether, polysulfone, polyethersulfone, polyarylate, polyetherimide, polyetheretherketone and the like. Can be mentioned. Hereinafter, the present invention will be described in detail with reference to embodiments.

[0008]

【Example】

 Example 1 A transparent conductive film in which a laminated film of indium oxide / silver / indium oxide was formed on a 100 μm thick polyethylene terephthalate film (hereinafter PET) was used as a panel heater substrate, and 125 mm (length) × 90 mm A piece having a width of 4 mm and a length of 125 mm having a thickness of 4 μm was formed by electroless plating on both ends of the cut piece having a width of 2 μm. Furthermore, an acrylic resin was applied to form a protective layer. The resistance between both electrodes of the formed panel heater was 4Ω. When power of 13 V and 3.3 A was applied to this panel heater in a constant temperature bath of -20 ° C, the surface temperature rose to 22 ° C in 1 minute.

Comparative Example 1 A transparent conductive film having the same size and configuration as in Example 1 was used as a panel heater base material, and a conductive paint (silver paste) was applied to both ends of the transparent heater film to a width of 4 mm. It was used as an electrode. When power was applied to this and a temperature rising test was performed, burns occurred in the transparent electrode portion of the panel heater and disconnection occurred.

Comparative Example 2 A transparent conductive film having the same size and configuration as in Example 1 was used as a panel heater base material, and a conductive paint (silver paste) was applied to both ends of this with a width of 4 mm. A copper foil having a width of 3 mm and a thickness of 35 μm was laminated with the agent, and a silver paste was further applied on the copper foil, followed by drying at 80 ° C. for 30 minutes to form a panel heater electrode. The same protective film as in Example 1 was laminated, and the same temperature rising test as in Example 1 was performed. The results were almost the same.

[0011]

[Effect of the device]

 As is clear from the above Examples and Comparative Examples, the present invention simplifies the manufacturing process and enables the manufacture of highly reliable panel heaters, which is a useful idea.

[Brief description of drawings]

FIG. 1 is a sectional view of a panel heater according to the present invention.

FIG. 2 is a cross-sectional view of a panel heater having a protective film according to the present invention.

FIG. 3 is a cross-sectional view of a conventional panel heater.

[Explanation of symbols]

 1 transparent substrate 2 transparent conductive film 3 metal electrode layer 4 metal foil 5 conductive paint 6 protective film

Claims (1)

[Scope of utility model registration request] 1. A transparent conductive film 2 formed on a transparent substrate 1.
A panel heater comprising a metal electrode layer 3 directly laminated thereon.