Patent ID: 6207330
Filing Date: 2001-03-27
Classification: G03F,H05K

Abstract:
An article of manufacture containing an identifying mark thereon which article is produced by etching the identifying mark in the article by a laser beam comprising:a first transparent substrate layer which is substantially unaffected by the laser beam;an intermediate opaque pattern forming layer on the first transparent substrate layer, which intermediate opaque pattern forming layer is a material which absorbs the laser beam and which is etched by contact with the laser beam to form openings in the intermediate opaque pattern forming layer forming an identifying mark in the intermediate opaque pattern forming layer which identifying mark cannot be seen with the unaided eye; anda second transparent substrate layer positioned on the intermediate opaque pattern forming layer;wherein either the first transparent substrate layer, second transparent substrate layer or both first transparent substrate layer and second transparent substrate layer contains a material which when activated provides a contrast between the identifying mark and the article so that the mark can easily be read.