In-line decay-time scanner

摘要

The disclosed scanner allows detecting decay time characteristics of light emitted by a luminescent marking on an item which is transported, even at high speed, on a distribution/production line. The detection zone of the scanner's light sensor has a shape elongated along a path of the moving item, and the responsivity of the light sensor, within the wavelength range of the emitted luminescence light, is uniform over the detection zone. The control unit of the scanner is further operable to adapt the drive current, or drive voltage, powering its excitation light source to accordingly adapt the intensity of the excitation light delivered to the marking so that its light sensor can reliably measure the corresponding luminescence light response, and thus accurately determine a corresponding decay time value.

主权项

1. A scanner for determining an intensity profile of luminescence light from a luminescent material moving past said scanner along a path in a first direction, said luminescent material emitting said luminescence light within a second wavelength range upon illumination with excitation light within a first wavelength range, comprising:
a power source; a light source connected to the power source and operable to illuminate with said excitation light the luminescent material within an illumination area, when powered by the power source; a light sensor operable to measure an intensity of said luminescence light received from the luminescent material being within a detection zone of said scanner, and deliver a corresponding luminescence intensity signal; and a control unit connected to the light sensor and operable to determine an intensity profile of said received luminescence light, from luminescence intensity signals delivered by the light sensor, wherein: said illumination area is at a first location along said path; said detection zone is at a subsequent second location along said path and extending along a portion of said path; said light sensor is operable to collect luminescence light from the luminescent material during its motion along the path in the first direction across the detection zone, measure an intensity of said collected luminescence light within said second wavelength range, and deliver a corresponding luminescence intensity signal, a responsivity of said light sensor within said second wavelength range is substantially uniform over said detection zone; and said control unit is operable to control said power source, light source and light sensor, and determine said intensity profile from the luminescence intensity signal delivered by said light sensor upon reception of luminescence light emitted by said luminescent material moving across said detection zone in the first direction, in response to illumination with said excitation light within said illumination area.