JP2001326136A - Conductive paste and nonlinear capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductive paste, which is used for the formation of the terminal electrodes of a nonlinear capacitor exhibiting satisfactory nonlinear characteristics, and to provide a nonlinear capacitor using the paste. SOLUTION: The conductive paste is used for the formation of the terminal electrodes of the nonlinear capacitor, which shows hysteresis in its electric field-charge characteristic and contains Ag powder, borosilicate glass, and an organic vehicle containing a resin component. The content of the resin component in the organic vehicle is adjusted to 4-14 volume % with respect to 100 volume % of the paste. The nonlinear ceramic capacitor is provided with a ceramic elemental body, showing a nonlinear characteristic and terminal electrodes which are formed by glazing the conductive paste to the elemental body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive paste and a non-linear capacitor suitable for forming terminal electrodes of a non-linear capacitor, and more particularly to a non-conductive paste and a non-linear capacitor for generating a high-voltage pulse necessary for starting a high-intensity discharge lamp (HID lamp). The present invention relates to a conductive paste suitable for forming terminal electrodes of a linear capacitor and to such a non-linear capacitor.

[0002]

2. Description of the Related Art Conventionally, high-intensity discharge lamps (HID lamps) such as high-pressure sodium lamps and metal hide lamps.
Requires a high voltage pulse of about 1 to 4 kV at startup,
Such an HID lamp has a built-in capacitor having non-linear characteristics for generating a high-voltage pulse.

[0003] Japanese Patent Publication No. 5-87940 discloses a high-pressure discharge lamp having a built-in non-linear capacitor for generating the pulse. Conventionally, a non-linear capacitor built into such a high-pressure discharge lamp is shown in FIG.
And will be described in detail. The non-linear capacitor 31 includes a ceramic element 32 made of, for example, a barium titanate-based ceramic, terminal electrodes 33, 33, and bonding materials 34, 34.
, And lead wires 35, 35 and a covering material 36. The terminal electrodes 33, 33 are formed by applying and baking a conductive paste made of, for example, a conductive powder, borosilicate glass, and an organic vehicle to both main surfaces of the ceramic element 32. Leads 35, 35 are electrically and mechanically joined by the members 34, 34. One end of the ceramic element 32, the terminal electrodes 33, 33, the joining materials 34, 34, and one end of the lead wires 35, 35
For example, it is covered with a covering material 36 made of a glass paste.

[0004]

However, in the conventional non-linear capacitor 31, when the conductive paste containing the borosilicate glass for forming the terminal electrodes 33, 33 is baked, the glass frit in the conductive paste is used. Is diffused into the ceramic element 32, which causes a problem that the non-linear characteristics are deteriorated.

As a method for solving this problem, according to Japanese Patent Application Laid-Open No. H11-214257, there is disclosed a method of forming a terminal electrode using a conductive paste containing lead-bismuth borosilicate glass or barium borosilicate glass. Linear capacitors have been proposed. An object of the present invention is to develop the above-described invention, and to provide a conductive paste and a non-linear capacitor used for forming a terminal electrode of a non-linear capacitor capable of exhibiting even better non-linear characteristics. .

[0006]

In order to achieve the above object, a conductive paste of the present invention is a conductive paste used for forming terminal electrodes of a non-linear capacitor exhibiting hysteresis in electric field-charge characteristics, It contains Ag powder, borosilicate glass, and an organic vehicle, and the resin component in the organic vehicle is in a range of 4 to 14% by volume of 100% by volume of the conductive paste.

A non-linear capacitor according to the present invention includes a ceramic body exhibiting non-linear characteristics and a terminal electrode, wherein the terminal electrode is formed by baking the conductive paste of the present invention onto the ceramic body. I do.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive paste of the present invention is made of Ag.
It contains powder, borosilicate glass, and an organic vehicle, and the resin component in the organic vehicle must be in the range of 4 to 14% by volume of 100% by volume of the conductive paste. That is, when the content of the resin component is 14% by volume or less, the combustion of the resin component and the sintering of Ag occur substantially at the same time, and the non-linear characteristics are sufficiently reduced without reducing the adhesion layer on the surface of the ceramic body. Can be withdrawn. When the content of the resin component is 4% by volume or more, the effect of adding the vehicle as described above can be obtained.

Next, one embodiment of the nonlinear capacitor of the present invention will be described in detail with reference to FIG. That is, the nonlinear capacitor 1 includes a ceramic element 2 made of, for example, a barium titanate-based ceramic, terminal electrodes 3 and 3,
It has a structure including bonding materials 4 and 4, lead wires 5 and 5, and a coating material 6. The terminal electrodes 3 and 3 are formed by applying and baking the above-mentioned conductive paste to both main surfaces of the ceramic element 2, and the lead wires 5 and 5 are electrically and mechanically joined by the joining materials 4 and 4. I have. One end of the ceramic element 2, the terminal electrodes 3 and 3, the bonding materials 4 and 4, and one end of the lead wires 5 and 5 are covered with a coating material made of, for example, glass paste.

Next, another embodiment of the nonlinear capacitor of the present invention will be described in detail with reference to FIG. That is, the non-linear capacitor 11 includes a ceramic element 12 made of, for example, a barium titanate-based ceramic and terminal electrodes 13 and 1.
3 The terminal electrodes 3 and 3 are formed by applying and baking the above-mentioned conductive paste to both end surfaces of the ceramic element 2.

Although the non-linear capacitor 1 according to the above-described embodiment includes the joining members 4 and 4, the lead wires 5 and 5, and the covering member 6, the non-linear capacitor of the present invention does not necessarily need to include these. Absent. In addition, the terminal electrode 1 is connected to the non-linear capacitor 11 in the other embodiments described above.
The second terminal electrodes may be formed so as to cover 3, 3 or a plating film made of electrolytic plating or the like may be formed so as to cover these.

[0012]

First, a disk-shaped ceramic body having a diameter of 18 mm and a thickness of 1 mm prepared by dry-pressing and firing barium titanate-based ceramic powder as a dielectric material exhibiting non-linear characteristics is prepared.

Next, Ag powder and 100% by weight of Ag powder
5% by weight of barium borosilicate (B-Si-Ba-
O) As shown in Table 1, with respect to 100% by volume of the conductive paste, 3.0% by volume, 4.0% by volume,
5.0 vol%, 10.0 vol%, 14.0 vol%, 1
An organic vehicle containing 5.0% by volume of a resin was added and mixed to prepare conductive pastes of Samples 1 to 6.

Next, a sample 1 was placed on both main surfaces of the ceramic body.
The conductive pastes Nos. 1 to 6 were printed to form an electrode film on a disk having a diameter of 17 mm, and baked at 850 to 900 ° C. to obtain non-linear capacitors of Samples 1 to 6.

Therefore, the generated pulse voltages of the non-linear capacitors of Samples 1 to 6 were measured using a circuit as shown in FIG. In the circuit shown in FIG. 3, a 400 W high-pressure mercury lamp stabilizer 22 is connected in series to a 200 V power supply 21.
6 nonlinear capacitor 1 and breakover voltage 1
A 50 V semiconductor switch 23 is connected in series, and a voltmeter is connected in parallel with the high-pressure mercury lamp ballast 22 and the nonlinear capacitor 1.

The conductive pastes of Samples 1 to 6 were printed on a slide glass plate and dried at 150 ° C.
~ 6 dried coating films were obtained.

Therefore, the dried coating films of Samples 1 to 6 were subjected to a scratch test with a diamond needle using a surface tester (manufactured by Shinto Kagaku), and the strength of the surface coating film was measured. Summarized in In addition, the strength of the dry coating film was evaluated as 荷重 when the load at which a scratch was generated was 10 g or more, ○ when the load was 5 g or more and less than 10 g, and × when the load was less than 5 g.

The evaluation was as follows: ○ for samples within the range of the present invention in which the pulse voltage is 2,000 V or more and the dry film strength is ◎ or ○, and the pulse voltage is less than 2000 V or the strength of the dry film. Samples outside the range of the present invention where X is indicated by X are indicated by X.

[0019]

[Table 1]

As is clear from Table 1, the samples 2 to 5 having a resin content of 4.0 to 14.0% by volume in the conductive paste have a pulse voltage of 2000 to 2300.
In all cases, V was a high value exceeding 2000 V. Also,
Regarding the strength of the dried coating film, the content was 5.0 to 14.0.
Samples 3 to 5 which are volume% are particularly excellent, and the strength which can endure practical use was able to be secured also for sample 2 having a content of 4.0 volume%.

On the other hand, the resin content was 4.0% by volume.
The sample 1, which was 3.0% by volume, which was lower than the above, produced a high pulse voltage of 2300 V, which was excellent. However, the strength of the dried coating film was weak at a load of less than 5 g, which was out of the range of the present invention.

Sample 6 having a resin content of more than 14.0% by volume and 15.0% by volume had an excellent dry film strength at a load of 10 g or more, but generated a pulse voltage of 200%.
It was 1800 V, which was lower than 0 V, and was out of the range of the present invention.

[0023]

As described above, the conductive paste of the present invention contains Ag powder, borosilicate glass and an organic vehicle, and the resin component in the organic vehicle is the conductive paste 1
By being characterized in that it is in the range of 4 to 14% by volume of 00% by volume, when it is used to form a terminal electrode of a non-linear capacitor, it has excellent adhesion at the interface with the ceramic body, There is an effect that the nonlinear characteristics of the nonlinear capacitor can be sufficiently exhibited.

Further, a non-linear capacitor according to the present invention includes a ceramic body exhibiting non-linear characteristics and a terminal electrode, wherein the terminal electrode is formed by baking the conductive paste of the present invention onto the ceramic body. Accordingly, there is an effect that a terminal electrode having excellent adhesion at the interface with the ceramic body is provided, and sufficient non-linear characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a non-linear capacitor according to one embodiment of the present invention.

FIG. 2 is a sectional view of a non-linear capacitor according to another embodiment of the present invention.

FIG. 3 is a circuit diagram used for measuring a pulse voltage of a non-linear capacitor in the embodiment.

FIG. 4 is a cross-sectional view of a conventional conductive paste and a non-linear capacitor using the same.

[Description of Signs] 1 Non-linear capacitor 2 Ceramic body 3 Terminal electrode

Claims (2)

[Claims] 1. A conductive paste used for forming a terminal electrode of a non-linear capacitor exhibiting hysteresis in electric field-charge characteristics, comprising: Ag powder, borosilicate glass, and an organic vehicle, wherein the organic vehicle comprises A conductive paste, wherein the resin component in the conductive paste is in a range of 4 to 14% by volume of 100% by volume of the conductive paste. 2. A ceramic body having non-linear characteristics, and a terminal electrode, wherein the terminal electrode is formed by baking the conductive paste according to claim 1 onto the ceramic body. , Non-linear capacitors.