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:
Jan. 08, 1991
Filed:
Aug. 10, 1989
Thomas M Dolash, Worthington, OH (US);
Paul G Andus, Powell, OH (US);
Mark E O'Loughlin, Columbus, OH (US);
Battelle Memorial Institute, Columbus, OH (US);
Abstract
Methods and apparatus for reading a luminescent and substantially transparent bar code 1 on a background surface 2 whose reflectance may vary over the coded area. Light 7 scans (70), and excites luminescence 8 in, the bar code 1. The light 7 also reflects (9) without luminescence from the background surface 2 of the bar code 1. A first electrical or optical signal 11 is provided (4) responsive to the reflected nonluminescent light 9, and a second electrical or optical signal 10 is provided (4) responsive to the luminescent 8. Typically the first signal 11 is processed (5) to provide a third signal 31 that varies with background reflectance substantially as does the second signal 10; and the second and third signals 10, 31 are combined (5) to provide a fourth signal 12 that is substantially independent of background reflectance in the coded area, and which is decoded (6) to provide the desired reading.