| 摘要 |
PURPOSE:To improve the measuring accuracy of a glass fiber bundle photodetector by disposing a light diffusing plate at the emitting end of a condensing glass fiber bundle and detecting it by a photodetector disposed at an interval, thereby reducing the variation in the detection signal. CONSTITUTION:A light diffusing plate 2 of opal glass or the like is disposed at the end terminal 6 of a condensing glass fiber bundle 1 for condensing incident light 5. The diffused light 7 from the plate 2 is detected by a photodetector 3 disposed at a predetermined interval l. When the l is set at 6.2 times of the radius H of the emitting end of the glass fiber bundle, the range of variation in the quantity of light received by the photodetector is reduced to 5%. When the light diffusing plate 2' disposed at the emitting end is bent to match the spherical surface having a diameter of the distance to the photodetecting surface of the photodetector 3, any incident light becomes constant luminous flux. Thus, it can reduce the variation in the detection signal and can improve the measuring accuracy. |
