Reflected light scanner with electrically programmable breadth of scan

摘要

The scanning zone is covered periodically between max. and min. ranges of the object by dynamic energisation of light-emitting diodes (1', 1") for short and long ranges with a periodic control voltage.When reflection is detected by corresp. photodiodes (2",2') the output of a driver circuit (39) is switched automatically and in combination with the control voltage via a linearising circuit (40) gives a digital and/or analogue reading of distance from the front (7) of the scanner.