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:
May. 12, 1992
Filed:
Nov. 29, 1990
Harold C Bowers, Rancho Palos Verdes, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
The helix (10) of the slow wave structure of a travelling wave tube is formed on a steel mandrel (12) by depositing the metal (44) of the helix on the mandrel and then coating the deposited metal with a photo resist (46). A laser light beam (24,26), having a cross section in the form of a short line, is focused upon the resist and moved linearly along the axis of the mandrel while the mandrel is rotated. The resulting helical exposure pattern on the photo resist is developed and the remainder of the undeveloped resist is then removed to expose a helical pattern (50,52) of deposited helix metal (44). The latter is subjected to etching processes so as to remove the deposited metal between the turns of the helical resist pattern (54,56), leaving a helix (44) of deposited metal on the mandrel underneath the resist. The resist is then removed and the mandrel etched away to leave the completed helix.