| 摘要 |
PURPOSE:To decrease the loss of light energy by using a light guide wherein the side of the rod made of transparent material is covered by a material or metal whose refractive index is smaller than that of said transparent material. CONSTITUTION:The light guide 16 is fixed to the wall of a case 2 by using resin 5. A high polymer material coating film 81 whose refractive index is smaller than that of quartz is formed on the side of a quartz rod 8 of the guide 16. In this constitution, since the light travelling in the rod 8 is totally reflected at the interface with the coating film 81, the loss of light energy is very small. |
