Inspection scanning system
Patent 4556903 Issued on December 3, 1985. Estimated Expiration Date: 
December 20, 2003. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 20, 2003. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3795452 3835249 Method of inspecting circuit boards and apparatus therefor Process and apparatus for the automatic inspection of patterns Scanning apparatus and method Ignition detector circuit Apparatus and method for examining printed circuit board provided with electronic parts Defect detecting apparatus and method Patent #: 4486777 InventorsAssigneeApplicationNo. 06/563482 filed on 12/20/1983US Classes:348/126, Of electronic circuit chip or board250/224, Article and light ray relatively moved during sensing250/458.1, LUMINOPHOR IRRADIATION250/488.1, Plural planar layer type356/237.3, Detection of object or particle on surface358/481Including a polygon reflectorExaminersPrimary: Britton, Howard W.Assistant: Peng, John K. Attorney, Agent or FirmInternational ClassesH04N 1/053 (20060101)H04N 1/047 (20060101) G01N 21/956 (20060101) G01N 21/88 (20060101) H04N 1/113 (20060101) AbstractA system for generating a substantially-continuous stream of binary signals representative of the presence of copper on the surface of a fluorescent substrate of a board. A beam is swept by mirror facets of a rotating mirror drum along a path on the board. When the beam strikes copper it is merely relected. When the beam strikes the substrate, a fluorescence is produced. The resultant light is gathered by cylindrical lenses and fiber optic bundles. The color of the light is blocked by filters and the fluorescence color energizes photomultiplier tubes. A threshold setting and sensing circuit senses the output of the photomultiplier tubes and controls their bias voltage to produce a constant level of output from fluorescence and then produces a stream of binary signals that are representative of the presence/absence of copper on the surface of the board. The swept beam is split to send a portion of its energy through an optical grating. The intermittent light passing through the optical grating is gathered by a fiber optic bundle and is sensed by a photomultiplier tube. The output of the photomultiplier tube is doubled in frequency and used to sample and store the binary signals in the memory of a scanning converter. The binary signals arrive in short bursts of higher-frequency signals separated by periods of absence of binary data. The binary signals stored in the scanning converter are then read out substantially continously for subsequent processing at a lower frequency.Other References
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