Dual-concave high-voltage ceramic capacitor and manufacturing process thereof

Abstract

The invention relates to a dual-concave high-voltage ceramic capacitor and a manufacturing process thereof. A ceramic dielectric substrate of the capacitor is shaped like a cylinder, two truncated cone-shaped gaps are formed in the cylinder, and then two concave portions are formed, that is to say, the thickness of the edge of the ceramic substrate is greater than that of the center. A transition surface with an arc line being the cross section is arranged between a round surface in the center of the ceramic substrate and a concave inclined surface of a truncated cone-shaped side surface. The ceramic substrate is provided with an electrode. The electrode is divided into three layers, wherein the top layer is tin alloy. The electrode is welded to a lead wire. Epoxy resin wraps the substrate, the electrode and part of the lead wire. The manufacturing process of the capacitor includes ceramic substrate manufacturing, electric polarization, lead wire welding, coating, printing, and testing. The electrode of the capacitor is manufactured through magnetron sputtering, and can be freely controlled in size. Through the design of the transition surface in the substrate concave parts, point discharge risks of the electrode are reduced, the over-voltage resistance of the capacitor is further improved, and the capacitor can become miniature. Through the design of a copper-tin alloy layer, the electrode can still be welded if part of the electrode is oxidized.

Description

technical field [0001] The invention relates to the field of ceramic capacitors, in particular to a high-voltage ceramic capacitor with a double-concave dielectric and adjustable electrode size and a manufacturing process. Background technique [0002] As a basic passive component, ceramic capacitors are widely used in power supplies, home appliances, automobiles and other equipment for filtering, oscillation and coupling. Traditional ceramic capacitors are discrete components, mainly cylindrical in shape. The molding process is simple, and the density of the green sheet after molding is uniform. It is convenient for sintering, printing electrodes, welding leads, and large-scale production. The current miniaturization development trend of electronic components is obvious. Patent CN202268250U discloses a high-voltage ceramic capacitor dielectric structure. The dielectric is double-concave. The breakdown mode of plate-type high-voltage ceramic capacitors is generally electrod...

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Problems solved by technology

Because traditional ceramic capacitors use the process of printing conductive paste and then sintering to prepare electrodes, when the patent CN202268250U dielectric structure prints conductive paste, due to the difference in the depth of the ceramic substrate, the force of the scraper is different, and the conductive paste will deposit in the concave shape, resulting in electrode thickness. Uneven, waste of conductive paste

Patent CN104167290A proposes a concave high-voltage ceramic capacitor, the dielectric structure of which is also concave, and a cylindrical vacancy is formed symmetrically on the upper and lower circular planes of the cylindrical dielectric, and its electric polarization process adopts the overall chemical deposition process. After the copper layer is deposited on the entire ceramic substrate, the copper layer on the outer surface of the ceramic substrate cylinder is ground to form an electrode. The thickness of the electrode layer is uniform. The disadvantage is that the electrode completely covers the circular surface of the substrate, and the electrode size cannot be adjusted, that is, the capacitance. It cannot be adjusted. In addition, the process of edging is easy to cause chipped corners of the substrate due to mechanical external force, which artificially causes process defects.

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