JP3192926B2 - Transparent nonlinear resistive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent non-linear resistive film having a small breakdown voltage, a coating material for forming the same, and a transparent varistor formed thereby.

[0002]

2. Description of the Related Art In general, as a non-linear resistance material, a varistor is known in which when a certain voltage is applied, the resistivity is sharply reduced and a current easily flows. The varistors
Widely used are zinc oxide-based materials such as those obtained by adding bismuth oxide and other additives to zinc oxide, and those obtained by adding rare earths and other additives such as praseodymium oxide to zinc oxide. . Each of these varistors is synthesized by sintering at a high temperature, then processed, and used as an electronic component.

A varistor is used to protect a circuit from an abnormal voltage when an abnormal voltage is applied to an electronic circuit, or to operate a circuit at a certain voltage or higher. Since recent electronic devices are in the direction of miniaturization, weight reduction, and power reduction, varistor films that operate at a low voltage and, in electronic display devices, transparent burrs that can be easily formed on a substrate. The appearance of a star film has been strongly desired.

[0004]

As described above, conventional varistor materials are made by heating and sintering various components at a high temperature, so that the varistor material is directly formed on a circuit or a substrate. It is difficult to form a film. In addition, as a method of forming a varistor film directly on a circuit or a substrate, the varistor is pulverized into fine particles, mixed with a dispersion liquid medium to form a paste, and such a paint is applied on a substrate by printing and dried. To form a varistor film. However, in the conventional varistor film obtained by such a method, the particle size of the varistor component particles is large, so that it is not possible to ensure transparency, and further, since the breakdown voltage of the varistor is high, Use in low voltage circuits has been difficult.

Accordingly, the present invention provides a transparent non-linear resistance film which can be formed directly on a circuit or a substrate of an electric device or the like and which can form a transparent varistor film which operates at a low voltage. It is intended to provide a paint and a transparent varistor formed thereby.

[0006]

According to the present invention, there is provided a coating material for forming a transparent nonlinear resistance film, comprising ultrafine zinc oxide particles having a particle diameter of 0.005 to less than 0.05 μm and a binder resin. It is. The transparent nonlinear resistance film of the present invention is formed by solidifying the coating material for forming a transparent nonlinear resistance film of the present invention. In the transparent nonlinear resistance film of the present invention, the content of the zinc oxide ultrafine particles is 50 to 50.
Preferably it is 95% by weight. A transparent varistor according to the present invention is a circuit or an electrode formed on a substrate made of plastic or glass, and a transparent non-linear resistance film formed thereon by solidifying the paint for forming a transparent non-linear resistance film according to claim 1. And In the transparent varistor of the present invention, the content of the zinc oxide ultrafine particles in the transparent nonlinear resistance film is preferably 50 to 95% by weight.

That is, in the present invention, the particle size is 0.0
A zinc oxide ultrafine particle of not less than 05 and less than 0.05 μm, a binder component, and a solvent if necessary, in a three-roll mill,
A ball mill, and kneaded to prepare a coating material by conventional dispersion methods such as a sand mill, direct application, a transparent non-linear resistance film is solidified by a printing method the coating on to the circuit or electrode creates a plastic substrate or a glass substrate Is formed to form a transparent varistor. As a film forming method, a film can be formed by an ordinary method such as screen printing, offset printing, gravure printing, roll coating, and spin coating.

Here, the particle size of zinc oxide is 0.05 μm or less.
When the upper der Ru is scattered light component of the light by the zinc oxide particles is increased, since the composed whitish appearance of the film, causing practical inconvenience in terms of transparency. The ultrafine zinc oxide particles used in the present invention include bismuth oxide, boron oxide, cobalt oxide, ultrafine particles added with manganese oxide, bismuth oxide, boron oxide, cobalt oxide, zinc oxide coated on the surface with manganese oxide and the like. Ultra-fine particles mainly composed of

The binder component used in the paint of the present invention includes an epoxy resin, a silicone resin,
Acrylic resin, polyester resin, vinyl resin,
Common materials such as thermosetting resins such as urethane resins and alkyd resins, and photosensitive resins such as ultraviolet curable resins, electron beam curable resins, and resists can be used.

The content of the ultrafine zinc oxide particles in the transparent nonlinear resistance film of the present invention , that is, the varistor film, can be appropriately set according to the electrical properties of the binder component.
A range of 0 to 95% by weight is preferred.

When a liquid medium (solvent) for dispersion is used in the paint of the present invention, there is no limitation on its type.
For example, butyl cellosolve can be used.
In general, it is preferable to use a solvent that dissolves the binder resin as the main medium for dispersing the ultrafine zinc oxide particles, since the quality of the obtained film is not deteriorated.

[0012]

The present invention will be further described with reference to the following examples.

Example 1 A varistor-forming coating composition was prepared according to the following composition. Ultrafine zinc oxide particles (ZnO # 100, 81 parts by weight, manufactured by Sumitomo Osaka Cement Co., Ltd.) (particle size: 0.005 to 0.015 μm) Epoxy resin (trademark: Epicoat 1001, 8.5 parts by weight) Oil-forming shell epoxy (Manufactured by Co., Ltd.) Hardening agent (trademark: Epicure X, manufactured by Yuka Shell Epoxy) 0.5 parts by weight

The above composition was kneaded in a roll mill for 3 hours to prepare a coating. This coating material was applied to a glass substrate with an ITO transparent electrode by screen printing, solidified to form a film, and baked at 200 ° C. for 1 hour to form a transparent varistor film.

The current-voltage characteristics (frequency 1 kHz) of the obtained transparent varistor film were measured.
Table 1 shows the film thickness and transmittance.

The evaluation of the current-voltage characteristics was performed by the method shown in FIG. That is, an ITO electrode 2 is provided on a glass substrate 3, a transparent varistor film 1 is formed thereon, and the electrode 2 is connected to a power source 4 having a frequency of 1 kHz. The ammeter A was arranged, and the breakdown voltage (V) was measured by changing the voltage of the power supply.

Example 2 A composition having the following composition was prepared. Ultrafine zinc oxide particles (ZnO # 100, 72 parts by weight, manufactured by Sumitomo Osaka Cement Co., Ltd.) UV curable resin (trademark: Lipoxy SP-1506, 17.5 parts by weight, manufactured by Showa Polymer Co., Ltd.) Curing agent (trademark: Irgacure 651, Ciba-Geigy) 0.5 parts by weight Butyl cellosolve 10 parts by weight

The above composition was kneaded with a three-roll mill for 3 hours to prepare a coating. This paint was applied on an ITO transparent electrode on a plastic substrate by screen printing, and this was irradiated with a 500 W ultraviolet lamp for 30 seconds to form a transparent varistor film. The current-voltage characteristics (frequency 1 kHz) of the obtained transparent varistor film were measured. The results are shown in FIG. Table 1 shows the thickness and transmittance of the varistor film.

[0019]

The composition was kneaded in a ball mill for 8 hours to prepare a coating. This paint was applied on a transparent ITO electrode on a glass substrate by a spinner, and then applied to the transparent electrode.
By baking at 0 ° C. for 30 minutes, a transparent varistor film was formed. The current-voltage characteristics (frequency 1 kHz) of the obtained transparent varistor film were measured, and the results are shown in FIG. Table 1 shows the thickness and transmittance of this varistor film.

[0021]

[Table 1]

As is apparent from FIG. 1, the transparent nonlinear resistance films (varistor films) obtained in Examples 1 to 3 exhibited excellent transparency and low breakdown voltage.

[0023]

As is apparent from the above description, the transparent varistor film according to the present invention has excellent transparency and has a low breakdown voltage. Can be operated at a low voltage. Furthermore, since the transparent nonlinear resistance film of the present invention can be formed by directly applying and curing on a circuit or a substrate, it is excellent in mass productivity and manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a voltage and a current of transparent nonlinear resistance films (varistor films) of Examples 1 to 3 according to the present invention.

FIG. 2 is an explanatory diagram showing a measurement circuit used for measuring the voltage-current characteristics of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transparent varistor film 2 ... ITO electrode 3 ... Substrate 4 ... Power supply A ... Ammeter

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01C 7/10 C01G 9/02

Claims (5)

(57) [Claims] 1. A transparent non-linear resistance film forming coating material comprising ultrafine zinc oxide particles having a particle size of 0.005 to less than 0.05 μm and a binder resin. 2. A transparent nonlinear resistance film formed by solidifying the coating material for forming a transparent nonlinear resistance film according to claim 1. 3. The content of the ultrafine zinc oxide particles is 50.
3. The transparent nonlinear resistance film according to claim 2, wherein the content is about 95% by weight. 4. A circuit or an electrode formed on a substrate made of plastic or glass, and a transparent nonlinear resistance film formed thereon by solidifying the paint for forming a transparent nonlinear resistance film according to claim 1. Having a transparent varistor. 5. The content of the ultrafine zinc oxide particles in the transparent nonlinear resistance film is 50 to 95% by weight.
The transparent varistor according to the above.