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:
Jul. 16, 1991
Filed:
Jun. 26, 1989
Diethelm G Ringleb, Andover, MA (US);
Andrew J LePage, Lowell, MA (US);
Digital Equipment Corp., Maynard, MA (US);
Abstract
A test cell for non-contact testing a circuit board for shorts and opens includes a hermetically sealable container for that circuit board, at least one wall of the container providing access to permit a circuit board to be positioned at an imaging plane inside the container. A pair of planar electrodes positioned inside the container are spaced on opposite sides of and parallel to the imaging plane and these electrodes are connected to contacts on the exterior of the container so that the electrodes can be releasably connected to an external voltage source to provide an electric field inside the container which extends perpendicular to the imaging plane. One of these electrodes and the container wall adjacent thereto are transparent to light from a pulsed laser positioned outside the container which is arranged to image a selected spot on a conductor of a circuit positioned at the imaging plane. One or more valved gas fittings are mounted to the outside of the container so that the container can be releasably connected to external gas conduits to fill the container with an inert gas. Also a sensor may be provided inside the container to sense the gas pressure in the container.