Patents by Inventor Carl D. Christy

Carl D. Christy has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Apparatus and method for detecting and sorting plastic articles having a preferred axis of birefringence
    Patent number: 5675416
    Abstract: A sorting system (10) propels a stream of randomly arranged PET and PVC articles (12, 14) through an inspection zone (20) including a first light polarizer/analyzer combination (24, 26), an article-detecting gap (G), and a second light polarizer/analyzer combination (28, 30). The first and second polarizer/analyzer combinations are oriented to extinguish normally incident light in the absence of articles in the inspection zone and are offset 45 degrees relative to each other such that at least one polarizer/analyzer combination detects a principal axis of birefringence of PET articles. The gap is employed to detect the presence of an article in the inspection zone. A video camera (22) includes first, second, and third CCD arrays (58, 60, 62) positioned to receive respective light rays (48, 64, 50) from the first light polarizer/analyzer combination, the gap, and the second light polarizer/analyzer combination and to generate first, second, and third video signals representative of the light each receives.
    Type: Grant
    Filed: January 22, 1996
    Date of Patent: October 7, 1997
    Assignee: SRC Vision, Inc.
    Inventors: Duncan B. Campbell, Carl D. Christy, H. Parks Squyres, Steven D. Lancaster