| 摘要 |
<p>PURPOSE:To improve the reliability of an information reader and at the same time to prevent the deterioration of service life of an LED by detecting optically the insertion of a recording medium to an insertion path. CONSTITUTION:A recording medium is put into a path 3, and a reflective hologram is set at a detection window 4. Thus the optical path is cut off between an LED7 and a photodetecting element 11 for waiting purpose, and the output of the element 11 is reduced. This output undergoes a comparison by a comparator 15 via an amplifier 14. Therefore, the reduction of output of the element 11 produces a high level output of the comparator 15, and a transistor TR12 is turned on. In this case, a route passing through a resistance 16 and a TR16 is also added to the LED7. Thus the LED driving current increases to produce the light of the maximum output. This reader facilitates detection of a photodetecting element 8. While the TR12 is kept off in a waiting mode. Therefore no reduction in service life of the LED is caused, and furthermore a light emitting output is secured to give satisfactory response to the element 11.</p> |
