| 摘要 |
PURPOSE:To accept any objects instead of limiting an object made of metal, to effectively eliminate the influence of external disturbance light with respect to the objects that are continuously carried in at a high speed and to surely detect the number of the objects by providing an opening stop and a visual field stop and deviating an optical path to the peripheries of the objects. CONSTITUTION:A passing-by hole 3 corresponding to the size of the object 2 is drilled on a frame 1 so as to penetrate vertically, and the object 2 passes through the hole 3. The optical path 15 is composed of a light source 4 and a photodetector 10 is deviated to the periphery of the object 2. Thus light emitted from the light source 4 comes out of a small hole 3 on the side of the hole 3, and the direction of the optical path 15 deviates from the center of the hole 3, whereby only the periphery of the object 2 blocks the optical path. The opening stop 8 and the visual field stop 9 are provided right after a lens 7, whereby the entry of external disturbance light can be blocked, and the malfunction of the light receiving side can be prevented which is caused by the influence of the external disturbance light. Namely the material of the object 2 is not limited to metal. Even if objects are continuously carried in at a high speed, the influence of the external disturbance light can be effectively eliminated, and the number of objects can be correctly detected.
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