| 摘要 |
PROBLEM TO BE SOLVED: To reduce the light absorptive loss by the case of a luminaire by forming a fluorescent lamp of a specific light emission tube, giving a specific value range to the ratio of the overall length of the lamp to the exposed length of the tube, and also giving a specific value range to the angle which the tangential line tying the tube center to the case periphery forms relative to the center axis. SOLUTION: This fluorescent lamp device has a light emission tube 1 in such a configuration that six straight bulbs 1a are connected together at the end part 1c and a part near the end part on the base end side so that one bent discharge path is formed as a whole, where electrodes are furnished at the two ends. A case 3 is structured so that the bas end of the tube 1 is supported by one end 3b and a base piece 4 is provided at the other end, and accommodates a lighting circuit to light the light emission tube so that the total power consumption becomes 25 W or below. The conditions D/L<=0.55 and 2θ<=57 deg. should be satisfied, where L is overall length of lamp, D is exposed length of tube, and θ is the mean of angles formed on the center line by the tangential line tying to the case periphery centering on the position D/2 away from the tip of the tube 1 on the lamp axis. |
