| 摘要 |
PURPOSE:To enhance the efficiency of collection of light and to improve sensitivity, by making the numerical aperture of a first optical fiber, which guides emitted light, smaller than the numerical aperture of a second optical fiber, which collects and guides the reflected light. CONSTITUTION:Light from a light source 1 is inputted through an input terminal of a first optical fiber 2, guided through the first optical fiber 2, and projected on a material to be measured 5 from a projecting/collecting terminal, which is formed by combining the first and second optical fibers 2 and 3, by way of branching part 4. The reflected light from the material to be measured 5 is collected by the projecting/collecting terminal, guided by the second optical fiber 3, and projected on a photoelectric converter 6 from a light receiving terminal. Then, the output is obtained from the photoelectric converter 6. The first optical fiber 2 is made of the cable having the small numerical aperture and the second optical fiber 3 is made of the cable having the large numerical aperture. |
