LUMINAIRE FOR LOW-TEMPERATURE USE

摘要

PROBLEM TO BE SOLVED: To increase the light flux of a fluorescent lamp in a low temperature range. SOLUTION: This luminaire is equipped with a coldest-point heating member 20 making substantially intimate contact with a tube-wall outer surface portion in the proximity of the coldest point in a lighted fluorescent lamp 30 and with a tube-wall outer surface portion higher in temperature than the coldest point to heat the tube-wall outer surface portion in the proximity of the coldest point by heat conduction. The axial length of the coldest-point heating member 20 is selected so that it can make substantially close contact with the tube-wall outer surface portion in the proximity of the coldest point (an outer surface portion of a glass tube 31 at an end part of the fluorescent lamp 30) and with the tube-wall outer surface portion higher in temperature than the coldest point (an outer surface portion of the glass tube in the proximity of a filament). Therefore, the coldest-point heating member 20 conducts the heat of the tube-wall outer surface portion higher in temperature than the coldest point to the tube-wall outer surface portion in the proximity of the coldest point in the fluorescent lamp 30 to heat it up, thus raising the temperature of the coldest point in the fluorescent lamp 30 and increasing the light flux of the fluorescent lamp 30 in a low temperature range.