JPH0440852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nonlinear capacitor for generating high voltage used in non-contact starters of discharge lamps and the like.

[Conventional technology]

Conventionally, ferroelectric ceramic capacitors, mainly made of barium titanate, etc., have been used for various purposes as electronic components. It is also used as a high-voltage pulse generating element in starters built into electric lights.

A high voltage pulse generating capacitor used for such purposes has conventionally been constructed as shown in FIG. That is, electrode films 2a and 2b are formed on both sides of a ferroelectric ceramic substrate 1, and the surfaces of these electrode films 2a and 2b are covered with inorganic glasses 3a and 3b, leaving the center portions of the electrode films 2a and 2b. , lead terminals 5a, 5b are fixed to the center portions of electrode films 2a, 2b with conductive adhesives 4a, 4b.

However, in a high voltage pulse generation capacitor having such a configuration, the lead terminals 5a, 5b
Conductive adhesives 4a and 4b for fixing the ferroelectric ceramic substrate 1 to the electrode films 2a and 2b diffuse into the grain boundaries of the ferroelectric ceramic substrate 1 through the electrode films 2a and 2b,
This adversely affects the various characteristics of the capacitor, lowering the value of the high voltage pulses generated, and furthermore, the electrostrictive phenomenon during the generation of high voltage pulses causes the ceramic substrate to break at the grain boundaries where the conductive adhesive has entered. There was a problem.

In order to solve this problem, the inventors of the present invention, etc.
Previously, we proposed the configuration shown in Figures 3A and B (Japanese Patent Application No. 281863/1983). That is, electrode films 2a and 2b are formed on both sides of a ferroelectric ceramic substrate 1, and the surfaces of these electrode films 2a and 2b are covered with inorganic glasses 3a and 3b, except for the current-carrying parts 6a and 6b for the electrode films. At the same time, conductive films 7a, 7b connected to the current-carrying parts 6a, 6b are formed on the outer surfaces of the inorganic glasses 3a, 3b, and the conductive films 7a, 7
Lead terminals 5 are attached on b with conductive adhesives 4a and 4b.
This is to fix parts a and 5b.

With this configuration, the conductive adhesive for fixing the lead terminals will not diffuse into the ceramic substrate through the inorganic glass and electrode film, effectively preventing a drop in the generated pulse voltage and destruction of the ceramic substrate. It is possible.

[Problem that the invention seeks to solve]

By the way, in the capacitor for high voltage pulse generation proposed above, in order to electrically connect the electrode films 2a, 2b and the lead terminals 5a, 5b, the conductive films 7a, 7b provided on the inorganic glasses 3a, 3b are used.
must be formed at a predetermined position so as to cover the current-carrying parts 6a, 6b of the electrode films 2a, 2b, which are usually formed at positions away from the center.

On the other hand, in this high-voltage pulse generation capacitor, the ceramic substrate is generally formed in the shape of a thin disk, so it has no directionality and is extremely difficult to position. Therefore, the conductive film 7
It is difficult to form conductive films a and 7b at predetermined positions by means such as printing, and it is especially difficult to form conductive films at predetermined positions on multiple ceramic substrates at once by means such as printing. The electrodes have to be aligned in a certain direction, which is extremely complicated, and sometimes leads to poor connection between the electrode film and the lead terminal.

The present invention was made in order to solve the above-mentioned problems in the previously proposed capacitor for generating high voltage pulses, and it is possible to extremely easily form a conductive film covering the current-carrying part without positioning the ceramic substrate. The purpose of the present invention is to provide a nonlinear capacitor for high voltage pulse generation.

[Means and actions for solving problems]

In order to solve the above-mentioned problems, the present invention forms electrode films on both sides of a disk-shaped ferroelectric ceramic substrate, and covers the surfaces of these electrode films with inorganic glass except for the current-carrying parts for the electrode films. Then, a circular conductive film concentric with the ceramic substrate is applied to the outer surface of the glass coating so as to cover the current-carrying part, and a lead terminal is connected to the conductive film avoiding the connection part with the current-carrying part. This constitutes a nonlinear capacitor for high voltage pulse generation.

With this configuration, it is possible to easily form a conductive film that covers the current-carrying parts regardless of the placement position of the current-carrying parts without aligning the ceramic substrate, effectively preventing the occurrence of connection failures. becomes possible.

〔Example〕

Examples will be described below. FIG. 1A is a sectional view of an embodiment of a nonlinear capacitor for high voltage pulse generation according to the present invention, and FIG. 1B is a top view thereof, and the same members as those in the conventional example are designated by the same reference numerals. It shows. In the figure, 1 is a disc-shaped ferroelectric ceramic substrate mainly composed of barium titanate, and electrode films 2a and 2b obtained by coating and baking silver paste on both sides of the ceramic substrate 1.
is formed. The surfaces of the electrode films 2a, 2b are covered with ferroelectric crystallized glass films 3a, 3b, except for the current-carrying parts 6a, 6b to the electrode films 2a, 2b. Since the conductive parts 6a and 6b lead out the lead terminals from the center of the ceramic substrate 1,
It is placed at a position offset from the center.

And on the outer surface of the glass films 3a and 3b,
Circular conductive films 8a and 8 made of, for example, a silver film are arranged so as to cover the current-carrying parts 6a and 6b of the electrode films 2a and 2b.
b is formed concentrically with the ceramic substrate 1.
Then, on the conductive films 8a and 8b, the conductive portion 6
A conductive adhesive 4 made of low melting point glass powder and silver powder is placed at an arbitrary position, in this example, at the center of the ceramic substrate 1, avoiding the connection position with a and 6b.
A and 4b are lead terminals 5 made of nickel or the like.
A and 5b are bonded together to form a nonlinear capacitor for high voltage pulse generation.

By forming the conductive films 8a, 8b in a circular shape concentric with the ceramic substrate 1 in this way, it is no longer necessary to position the ceramic substrate 1 according to the arrangement positions of the current-carrying parts 6a, 6b.
Regardless of the arrangement position of a, 6b, the current-carrying parts 6a, 6
The conductive films 8a and 8b can be easily formed so as to cover the conductive films 8a and 8b, and the occurrence of poor connections and the like can be completely prevented.

In the above embodiment, the lead terminals were drawn out from the center of the ceramic substrate, but in order to correspond to the mounting location of this nonlinear capacitor, the lead terminals should be placed on the conductive film at any location other than the connection location of the current-carrying part. It can be fixed to any desired part of.

〔Effect of the invention〕

According to the present invention, since the conductive film for connecting the current-carrying part of the electrode film and the lead terminal is formed in a circular shape concentrically with the ceramic substrate, the current-carrying part can be connected without aligning the current-carrying part. A covering conductive film can be easily formed, and occurrence of poor connections and the like can be reliably prevented.

[Brief explanation of drawings]

FIG. 1A is a sectional view of a nonlinear capacitor for high voltage pulse generation according to the present invention, FIG. 1B is a top view thereof, FIG. 2 is a sectional view of a conventional high voltage pulse generation capacitor, and FIG. Figure A is a cross-sectional view of the high voltage pulse generation capacitor proposed earlier, Figure 3B
is a top view thereof. In the figure, 1 is a ferroelectric ceramic substrate; 2 is a ferroelectric ceramic substrate;
a, 2b are electrode films, 3a, 3b are ferroelectric crystallized glass films, 4a, 4b are conductive adhesives, 5a, 5
b is a lead terminal, 6a, 6b are current carrying parts, 8a, 8
b indicates a conductive film.

Claims (1)

[Claims] 1. Electrode films are formed on both sides of a disk-shaped ferroelectric ceramic substrate, and the surfaces of these electrode films are covered with inorganic glass except for the current-carrying parts to the electrode films,
A circular conductive film concentric with the ceramic substrate is applied to the outer surface of the glass coating so as to cover the current-carrying part, and a lead terminal is connected to the conductive film avoiding the connection part with the current-carrying part. Nonlinear capacitor for high voltage pulse generation.