| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent an optical scanner from being kept in a nonoperating state under a certain optical condition by using a circuit incorporating a photodetector which converts scattered light from a visual code into an electric current. SOLUTION: A bar code scanner 200 is constituted of a laser 202, a reflecting mirror group 204, a scanning surface 206, a processing substrate 208, a motor 210 for rotating the mirror group 204, and a power source 212. The substrate 208 is constituted of a photodetector 214, another related processor 216 which is used for processing input signals and outputting information to, for example, a data base, and a current limiting means 218. The means 218 having an upper limit current which can be passed through the photodetector 214 is connected to the photodetector 214. Therefore, the scanner 200 can be restored quickly from the overload of strong light and can be substantially made to operate continuously.</p> |
