| 摘要 |
<p>PURPOSE:To prolong the service life of laser diode by turning on and off a laser beam generating element so as to intermittently generate a laser beam and, upon detecting the reflected light of the laser beam, continuously keeping the element in the turned-on state. CONSTITUTION:A laser beam generation controlling section 14 intermittently generates a laser beam by turning on and off a laser beam generating element in a laser scanning section 13 at a prescribed duty. When a photodetector 16, binarization circuit section 17, and signal processing section 18 detect the reflected light of the laser beam from a bar code 12 during the intermittent generation of the laser beam, the section 14 continuously generates the laser beam by keeping the laser beam generating element in the turned-on state. When the reflected light from the bar code 12 is not detected for more than a prescribed period of time during the continuous generation of the laser beam, the section 14 switches the generation mode to the intermittent mode. Therefore, the laser beam generating time can be reduced and bar codes can be surely read. In addition, the service life of the laser generating element can be prolonged.</p> |
