PROBLEM TO BE SOLVED: To provide a light quantity detection device capable of highly accurately adjusting a quantity of light by changing a distance between a light exit part and an incidence plane.SOLUTION: A light quantity detection optical fiber 26R for guiding laser light from a red light source includes an exit end 33 fitted to a holding member 51. A rotating body 52 disposed in a recessed part 51a of the holding member 51 includes a screw hole that is threadedly engaged with a long screw 56 erected on a substrate 41, so that the rotating body is fitted therein movably in the longitudinal direction, and when the rotating body 52 is rotated, along with the rotating body 52, the holding member is moved along the longitudinal direction. This configuration can vary a distance L toward a photodiode 27R facing the exit end 33 so as to adjust the quantity of the laser light incident on the incidence plane 34.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2017,JPO&INPIT【課題】光出射部と入射面との距離を変更して高精度の光量調整を可能とする光量検知装置を提供する。【解決手段】赤色光源によるレーザ光を導光する光量検出用光ファイバ26Rの出射端33は保持部材51に取り付けられ、保持部材51の凹部51a内に配置された回転体52は、そのネジ孔が、基板41に立設された長ネジ56に螺合して、その長手軸の方向に移動自在に取り付けられ、回転体52を回転することにより回転体52と共に、保持部材を長手軸に沿って移動し、出射端33と対向するフォトダイオード27Rとの距離Lを可変して入射面34に入射するレーザ光の光量を調整可能にしている。【選択図】図4
