| 摘要 |
<p>Disclosed is an optical reading method with which can be realized a system that compensates for handling of an information pattern not recognizable to the naked eye, wherein a nonvisible information pattern such as a bar code or a QR code is printed on an information recording medium or an object to be managed, and that provides high security or guaranteed product quality. When an information recording medium (11) having an information pattern (12) is placed in or transported to a prescribed position, the information pattern (12) is irradiated with excitation light (H1), which is emitted from a light-emitting diode (13) and has higher energy than the band gap of a semiconductor quantum dot, and the semiconductor quantum dot is thermally expanded. Then, light is emitted from the thermally-expanded quantum dot with a wavelength which transitions to the long-wavelength side compared to the wavelength emitted from the quantum dot prior to thermal expansion, this light beam is received by an optical sensor (14), which has a sensitivity to the longer wavelength portion of light which is emitted and transitions to the long-wavelength side, and the information pattern (12) is read by an information judgment unit (15).</p> |
