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:
Nov. 01, 1994
Filed:
Oct. 28, 1991
John B Roes, San Diego, CA (US);
Cubic Automatic Revenue Collection Group, San Diego, CA (US);
Abstract
A permeable electrostatic shielding method and apparatus is disclosed that is suitable for use in shielding portable electronic devices such as calculators, smart cards and radios. Such electronic devices require protection from the electrostatic discharge occurring when a user accumulates an electrostatic charge and contacts a conducting surface of the electronic device. The resulting electrostatic discharge creates capacitively-coupled voltage transients in the digital circuits within the electronic device. The present invention prevents local charge accumulation on the surfaces of such electronic devices, which transmit and receive electromagnetic radio waves, without blocking the electromagnetic radiation essential to device function. One embodiment of this permeable electrostatic shield is formed by depositing a conductive layer of controlled thickness comprising a plurality of closely-spaced conductors that are electrically connected at one end to form a practical electrostatic shield permeable to RF electromagnetic radiation above 15 MHz.