发明授权
US4251798A Portable laser scanning arrangement for and method of evaluating and validating bar code symbols 失效
便携式激光扫描装置以及评估和验证条码符号的方法

Portable laser scanning arrangement for and method of evaluating and
validating bar code symbols
摘要:
Laser light reflected from a bar code symbol pattern is detected by a photodetector mounted in a portable scanning head of a laser scanning system. By selecting appropriate threshold values on the analog signal generated by the photodetector, the analog signal is converted to a series of pulses, each pulse width accurately corresponding to the width of a bar from the scanned pattern. A plurality of functions can be determined from the series of pulses, each function being independently selected by keyboard entry from the head, displayed on the head, and/or recorded by a printer remote from the head. Single line or multiple line scans in two orthogonal directions relative to the pattern may be selected. A bimorph or speaker-type oscillatory element may be utilized as a miniature scanning element. Circuitry for synchronizing scanning along both axes, and for generating a signal to drive the bimorph in a uniform, constant velocity manner is also disclosed.
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