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:
Aug. 31, 1993
Filed:
Dec. 20, 1991
Gary Stout, Gloucester City, NJ (US);
Robert W Ashcraft, Towanda, PA (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A process is disclosed for applying a preformed photopolymerizable solder mask film and a photosensitive liquid to a printed circuit substrate containing a plurality of holes wherein reduced failure is obtained in photopolymerized areas of the solder mask film above the holes as determined after a soldering operation. The photosensitive liquid contains at least one ethylenically unsaturated compound capable of forming a high polymer by addition polymerization and a first photoinitiator system which has an absorption maximum in a first spectral region. The preformed photopolymerizable film contains at least one ethylenically unsaturated compound capable of forming a high polymer by addition polymerization and a second photoinitiator system, such that the preformed photopolymerizable film has an absorption maximum in a second spectral region and is activated by actinic radiation therein and has an absorption minimum in the first spectral region and transmits actinic radiation therein.