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:
Mar. 09, 1993
Filed:
Oct. 30, 1989
Stephen C Barratt, Hornchurch, GB;
Brian W Grant, Chelmsford, GB;
Alcatel Business Systems Limited, Romford, GB;
Abstract
Protection of electronic circuits from static electrical discharge is provided by utilizing a key mat, having key buttons moulded therein, of a key board for the circuits to provide an electrically insulating barrier to such discharges. The electronic circuits are housed in a housing having apertures through which the key buttons extend. Electrical discharge from a key button through the aperture in the housing to the circuits is prevented by forming the mat to have an extent sufficient to ensure that any discharge track is longer than that for a predetermined potential. Where the direct distance to a circuit is short the mat is formed so as to ensure a discharge track greater than the direct distance and of sufficient length. For this purpose the mat may be formed with an upstanding wall. A housing may have a cooperating wall to lengthen the air path.