Pulse-Train-Mode Optical Scanner
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
This article describes an optical scanner in which the scanning laser would operate in a pulse-train mode. Selection of the proper duty cycle would allow government regulations regarding exposure to be met without timer/accumulator circuitry. The need for item sensors would be eliminated, and ambient light rejection would be improved. Semiconductor lasers can be operated in a pulse-train mode with very narrow pulse widths and very high pulse repetition frequencies. In a bar code scanner, a semiconductor laser could operate in a pulse-train mode continuously. If the pulse train had a 10% duty cycle (10% on, 90% off), current government regulations regarding exposure to laser light at a given point would be met without any requirement for timers/accumulators.