| 摘要 |
PURPOSE:To enable an increase of the difference in the quantity of light between a high level and a low level and to generate a stable output by forming both top ends of optical fibers connecting a light emitting element to a photodetector into a flat shape, bringing both fibers into face-to-face contact with each other and joining the fibers. CONSTITUTION:The top ends 4, 5 of both fibers are bundled to one body by bringing the peripheral surfaces thereof into face-to-face contact with each other and are disposed to face a detecting slit 3 apart at a distance Z. The ends 4, 5 are juxtaposed with the moving direction A of the slit 3 so that the extending direction of an effective reflecting area P and the extending direction of a reflecting surface 3a are made coincident with each other. Even if both right and left ends P1, P2 of the area P overlap partly on the reflecting surfaces 3a, 3a positioned on both surface of the non-reflecting surface 3b, the light reflected by the right end P2 cannot be made incident to the inside of the fiber end 5 having a flat shape. The quantity of the light which a phototransistor receives is therefore diminished even if the area of the parts P1, P2 where the surfaces 3a, 3a and the area P overlap is increased by increasing the distance Z. |
