| 摘要 |
PROBLEM TO BE SOLVED: To provide a liquid level sensor of a simple structure having good sensitivity and excellent durability. SOLUTION: A total reflection optical path 6 for sealing a propagating light by forming a reflecting film 5a of aluminum or the like by vapor-depositing on an overall peripheral outer surface of a photoconductor 4 except a length range L selected by considering a difference between high and low liquid levels to be expected is constituted on the photoconductor 4 for optically coupling a light emitting element 2 to a photodetector 3. A sensing portion 8 for emitting scattered components of a propagated light out of the photoconductor 4 is constituted by forming a reflecting film 5b of aluminum or the like having a window 7 for emitting scattered components substantially uniformly distributed on an overall peripheral outer surface of the photoconductor 4 in the selected length range L. Thus, the propagated light emitted from the element 2 and passed through the photoconductor 4 is sensed by the photodetector 3, thereby detecting the liquid level corresponding to an attenuated amount of the light at the portion 8. |
