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. 28, 2000
Filed:
Oct. 08, 1998
Albert Holliday, Langhorne, PA (US);
Ralph E Stenerson, Jr, Newtown, PA (US);
Lucent Technologies, Inc., Murray Hill, NJ (US);
Abstract
An apparatus is used to inspect an assembled circuit board having a device assembled to the circuit board by a ball grid array (BGA). The BGA includes a plurality of rows of solder connections. The apparatus has a source of light, which may be a laser. A first deflector is positioned to direct the light into a first side of the BGA, between two adjacent rows of solder connections in the BGA. A second deflector directs any light emitted from a second side of the BGA opposite the first side onto a target. The deflectors may be prisms, mirrors, or optical fibers. The target may be a viewing surface (such as a wall or screen) or a light detector, such as a camera, frame grabber, or photoelectric device. The absence of light on the target while the light is directed into the first side of the BGA indicates the presence of a solder bridge in the BGA. The light source, deflectors and detector may be moved at a constant rate along the length of the BGA, to provide a pattern of alternating light and dark illumination levels. The presence of a solder bridge may be detected based on the pattern.