| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a code reader capable of reading a visible code read on the basis of a reflectance difference of light and an invisible code formed of a fluorescent material by a single device, not having reduction of code reading accuracy by a band cut filter differently from before, and hardly receiving influence of detection sensitivity wavelength dependence of a photoelectric conversion element. <P>SOLUTION: An excitation wavelength of the fluorescent material forming the invisible code is set as a wavelength shorter than a light source wavelength for the visible code read by the reflectance difference by absorption, transmission or reflection of the light, and light emission wavelength is set as the vicinity of the light source wavelength for the visible code. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
