| 摘要 |
PURPOSE:To enable detection of a boundary surface of 2 medium even if its difference of index of refraction is small, by improving a detecting capacity by means of a vapor deposition film on the end surface where an optical fiber comes into contacts with a medium. CONSTITUTION:A beam of light guide by an optical fiber 7 is transmitted through the optical fiber 7 and reaches an end surface coming into contact with a medium. This end surface is provided with a vapor deposition film 8, a part of the transmitted beam is reflected into the fiber 7 and this reflected beam is led to an optical detector 3 by a direction-controlled composition apparatus 4. In this case, the index of refraction R on this end surface is given by the Formula. Consequently, for example, the end surface of the optical fiber 7 with vapor deposited film of titanium oxide changes the indes of reflection more with respect to the index of refraction of a contacting medium as compared with that of the optical fiber 2 of the conventional sensor, resulting in a higher detecting capacity of a liquid level and a boundary surface of 2 mediums of a small difference of index of refraction can be detected. |
