| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical reader capable of enhancing reliability. <P>SOLUTION: This optical reader for detecting a mark by radiating excitation light to the mark 84 for detection containing a phosphor is provided with: a light radiation means 151 for radiating excitation light having nearly constant intensity at a predetermined cycle; a photoelectric conversion means 153 for introducing phosphorescence to convert it to an electric signal; a waveform detection means 154 synchronized with the radiation timing of the light radiation means 151 for individually detecting the minimum value corresponding to a time immediately before the radiation start, the maximum value corresponding to a time immediately before the radiation stop, and a detection value immediately after the radiation stop; and a determination means 155 for determining a mark formation position when the detection value exceeds a comparison value between the maximum value and the minimum value by comparing the comparison value with the detection value. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
