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Producing Accurate Photographic Plates

IP.com Disclosure Number: IPCOM000098591D
Original Publication Date: 1959-Jun-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Couden, DV: AUTHOR

Abstract

The manufacture of printed circuits and the preparation of coded black and white representations on film require patterns having dimensional tolerances as close as. 0005 of an inch.

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Producing Accurate Photographic Plates

The manufacture of printed circuits and the preparation of coded black and white representations on film require patterns having dimensional tolerances as close as. 0005 of an inch.

A method for achieving this accuracy consists of coating a large glass plate with a suitable emulsion and engraving the emulsion several times the desired size in accordance with the desired pattern using a spring loaded engraving tool mounted in a high precision jig boring machine. The spring loading assures removal of the emulsion along the lines of the pattern without scratching the glass plate. The emulsion is such that only those areas under the tool surface are removed, i. e., it does not chip or flake so as to create a ragged line.

The completed glass plate with engraved pattern is then photographed with a reduction to the final desired size onto a second glass plate which is suitably coated with photographic emulsion. The second glass plate then forms the master from which a number of patterns on film can be made by a simple contact printing process. In printed circuit applications the printed circuit board is etched using the second glass plate as the master.

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