| 摘要 |
PURPOSE:To constitute optically transparent plates in a simple shape by disposing the optically transparent plates at a constant angle in such a manner that when liquid is in contact with the 1st interface, the light from a light emitting element causes total reflection on the 2nd interface. CONSTITUTION:The liquid to be detected can enter freely the region C enclosed by transparent plates 4 and 6. The point where the light from a light emitting element 7 arrives at the 2nd interface when the liquid enters the region C and contacts with the 1st inteface A is defined as point Q', and the point where the light arrives at the 2nd interface when the liquid is not in contact with the 1st interface A is defined as point Q. The angle alpha of the plates 4 and 6 is so set that the incident angle to the interface at the point Q' attains more than the critical angle. In this case, the greater part of the light arriving at the point Q arrives at a photodetector 8, but the light arriving at the point Q' totally reflects, hence this results in that the light from the element 7 does not arrive at the photodetector 8. |
