Bar code reader coping with highly reflective surfaces - uses blocking circuit to process signals obtained from polarised beam scanning unit

摘要

Polarised light (8) is directed onto a stationary mirror (16) that provides a 90 deg. deflection onto an oscillating mirror (18) that causes the surface of the object contg. the bar code to be scanned (2). The reflected signal is directed (14) onto a blocking unit (3) that suppresses surface reflection effects. - The transmitted component is passed to an opto-electrical detector that contains an A-D converter stage. The digital signal is received by a bar code width logic unit (5) coupled to a decoder (6) to provide the data.