JPS5885502A - Method of producing thick film varistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention is a thick film in which a pair of electrodes are provided on the varistor holder, which is provided on an electrically insulating substrate and is made of ZnO sintered powder and a glass frit for bonding the varistor. The present invention relates to a method for manufacturing a varistor.

The purpose is to provide a thick film varistor with excellent acid resistance during plating.

A thick film made of ZnO sintered powder and glass frit has been developed and put into practical use as a microscopic film.

Fig. 1 is a plan view of an example of the basic structure of a varistor reduced to the conventional thickness j1, and Fig. 2 is a cross section taken along line C-Q' in Fig. 1-1. 1C1 electrical insulation 1'l +l1lJ ;”
! Alumina substrates with l 1/I-, 2a and 2b
l, f, electric 11 total, 3V1 varistor film made from zinc oxide powder and glass, 4 is an insulating coating layer that also contains low melting point glass (~ < 1 Lugis), ink, etc. It is.

In the case of the conventional thick film varistor mentioned above, there are the following drawbacks: Silver is used in the 1/I1 part. Il,′
There is a problem that silver cracks occur on j. 1) For items with small 7E electrode areas, such as chip parts, 4...C was a fatal problem. J of chip parts: i = - and e' for those with small electrode area:
Processing such as solder plating on the electric contact part and half 11 stitches/1
It was necessary to measure the characteristics of ``disposability''. Therefore, we applied treatments such as half-11'' plating to conventional thick film varistors, but
Since the varistor film does not have a structure in which the side surfaces thereof are completely insulated, the characteristics of the varistor film are adversely affected by strong acids such as half-1 x 1 plating liquid.

The present invention solves the drawbacks of the conventional thick film varistor, and applies a thickening agent to the ZnO sintered powder and glass frit directly or through an electrode on an electrically insulating substrate. A paste containing a solvent is applied and baked at a temperature higher than the melting point of the glass to form a varistor film, and an electrically insulating paste (low melting point glass, resist ink) is applied.
is applied to the upper and side surfaces of the varistor film and dried or baked to completely insulate the varistor film including the side surfaces.

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. In FIG. 3, reference numeral 5 denotes an alumina substrate which is electrically insulating and highly heat-resistant, and electrodes 6a are provided on this substrate by printing and baking silver paste or the like.

Next, a paste made of ZnO sintered powder, glass frit, and a solvent containing a thickener is applied onto the electrode 6a, and even if the thickness of the glass is 1 ml or more, , a varistor film 7 is formed as shown in FIG. An insulating coating layer 8 is provided by the method described above to form an integral structure.

1]-, the insulating coating layer 8 is formed by printing or drying a paste type low melting point glass, regimen ink, etc.; It has good adhesion with the electrode 6b, and has excellent electrical insulation properties.

The varistor film 7 is made of an acid-resistant composition, and is adjusted to an excessive thickness so as to completely cover the varistor film 7 including its side surfaces. The insulating coating layer 8 configured in this manner has excellent acid resistance at 7 hours, and has the same acid resistance as the varistor film 7 at the time of meshing. (V6&, 6b plated without degrading the characteristics of the varistor film γ.)
According to 111, solder or the like is used as a working oil, and the soldering of the electrode portion of the thick film varistor is made to have a tendency of −L−k ”J.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an example of the basic structure of a conventional thick film varistor, Fig. 2 is a sectional view taken along line c-c' in Fig. 1, and Fig. 3 is a varistor obtained by the manufacturing method of the present invention. FIG. 2 is a cross-sectional view showing an example of a thick film varistor. 5...Alumina substrate, 6a, eb...°゛°
°Electrical film...Varistor film, 8.°°...Insulating coating layer. Name of agent Patent attorney Satoshi Nakao Ka Haga1 person No.1
Figure ↑ θ' Figure 2 Figure 3

Claims (1)

[Claims] Zn is deposited on the electrically insulating substrate directly or through an electrode.
A paste made by adding a solvent containing a thickener to O sintered powder and glass glue is applied and baked at a temperature above the melting point of glass to form a risk film, and then an electrically insulating paste is applied as described above. 1. A method for manufacturing a thick film varistor, in which the varistor film, including the side surfaces, is completely covered with an insulating coating layer by coating a portion of the varistor film and the side surface, and drying or baking.