The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 28, 1980
Filed:
Nov. 15, 1978
Ewald Losert, Rheinfelden, CH;
Heinz Rembold, Arlesheim, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
A process for producing solder masks on double sided printed circuit boards, comprising conveying the boards beneath a free falling curtain of a pohotopolymer to form a thin layer on a surface of the board, irradiating with ultra violet light areas of the surface other than those that need to be soldered and then, by subsequent development, dissolving the unirradiated areas of the layer. The viscosity of the photopolymer is between 500 to 1200 mPa's at impingement on the surface of the circuit and the height of the curtain is selected so that the rate of flow of the polymer onto the circuit is between 60 to 160 m/min. Also the rate at which the circuits are conveyed beneath the curtain is greater than a rate slightly less than the rate at which the polymer flows onto the circuit.