| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an annular fluorescent lamp that ensures a desired temperature at the coldest portion by forming a ventilation hole whose base intends to have the coldest portion and can improve luminescent efficiency of the annular fluorescent lamp with especially small pipe diameter, and a luminaire mounted with this annular fluorescent lamp. SOLUTION: A plurality of slit-shaped ventilation holes 13 with 1-2 mm width and 5 mm length are provided for the bulb end 5 side of a base 3 surrounding the base 3, the end 5 and an end surface 5a of a bulb 2 are exposed to outside at part of the ventilation holes 13. Filament electrodes 7, 8 are sealed in the bulb ends 5, 6 by inner wells 9, 10 and stems 11, 12, height of one filament electrode 7 is higher than that of the other filament electrode 8 and 30 or 50 mm. When an annular fluorescent lamp 1 lights up, convection occurs inside and outside the base 3 through the ventilation holes 13. This convection flows along the end surface 5a and the end 5 of the bulb 2 to form the coldest portion on the inner surface side of the bulb end 5.</p> |
