| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-illuminance light and an ultraviolet ray of a large intensity at the center of a light flux radiated from a light-radiating end. SOLUTION: With a light-incident end 50 of a light guide 5 approximately normal to the horizontal axis H-H, an optical axis Z-Z for a metal halide lamp 3 and a reflective surface 40 is at an angle to the light-incident end 50 and the horizontal axis H-H so that a first focus F1 is located below a second focus F2. Consequently, a low-illuminance light through a haloid deposit 7 in an arc tube 30 is incident upon the light-incident end 50 with a larger angle while a high-illuminance light not through the deposit 7 is incident upon the light-incident end 50 with a smaller angle. The low-illuminance light is radiated from the light-radiating end 51 with a larger angle, and the high-illuminance light is radiated from the light-radiating end 51 with a smaller angle. The high- illuminance light and an ultraviolet ray of a large intensity are thus obtained at the center of a light flux radiated from the light-radiating end 51. |
