Ecco Limited

Littlefuse, Inc.

Anthony L Oliver

Stephen P Cowman

Derek A Nicker

John M Shreeve

Alan J Ratcliffe

Apparatus for producing multilayer varistors using ceramic ink and electrode ink consists of a succession of stations, in which alternating layers of ceramic ink and electrode ink are laid down on a substrate. The stations may be printing stations in which either a ceramic ink screen or an electrode ink screen is used to apply the appropriate ink to the substrate. In a first printing step, a layer of ceramic ink is laid down, within a region determined by a mask area of a ceramic ink screen. In the following step, electrode ink is laid down in regions determined by mask areas of the electrode ink screen. The apparatus includes transfer mechanisms for advancing substrates from station to station for successive printing operations, and control mechanisms for regulating and coordinating the successive printing operations and substrate travel.

Varistor manufacturing method

A method for use in making multilayered varistors including the steps of forming a plurality of interleaved layers of ceramic material and conductive material, confining the conductive material to spaced areas arranged in rows and columns, displacing the spaced areas of adjacent layers of conductive material from each other, and cutting perpendicularly through the layers. The layers are formed by screen printing.

Method of manufacturing varistor precursors

In a varistor of generally cylindrical configuration, which may serve as a connector pin, layers of ceramic material are interleaved between layers of electrode material, each ceramic layer being sandwiched between two electrode material layers. Each layer of electrode material is generally planar and extends transversely to the axis of the cylindrical varistor, in the form of an annular ring. Each alternate annular ring is of different inner and outer diameter. The outer periphery of each larger diameter annular ring is in electrical contact with an outer terminal cap of the varistor, while the inner periphery of each smaller diameter annular electrode layer is in electrical contact with an inner terminal cap extending along a central bore passing axially through the varistor pin. Each ceramic layer may have a thickness dimension less than 30.0 microns, or may be formed by deposition of a powder suspension and subsequent heat treatment to provide a dense continuum of ceramic material of low porosity.

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Great Yarmouth, United Kingdom

Anthony L Oliver