| 摘要 |
PURPOSE:To detect a liquid surface highly accurately with simple constitution by receiving luminous flux from a luminous flux generating means by a light receiving means and detecting the liquid level according to its light receiving level. CONSTITUTION:The liquid crystal sensor is constituted of a luminous flux generation source 3 and a photodetector 4, which are so arranged that the light receiving level of the photodetector 3 is a high value unless the liquid surface 8 is interposed the generation source 3 and element 4. When the liquid surface is present between the generation source 3 and element 4, on the other hand, the luminous flux 5 is refracted and reflected by the liquid surface 8 and made incident on the element 4, whose detection level becomes low. For the purpose, a proper light quantity level is set and used for comparison to detect whether or not there is the liquid surface 8 between the generation source 3 and element 4. Consequently, the liquid surface can be detected highly accurately with the simple constitution. |
