MERCURY VAPOR LOW VOLTAGE DISCHARGE LAMP

To reduce the operating temperature of a U-shaped or multiple U-bent fluorescent lamp, the respective longitudinal and transverse sectional elements of the U-shaped lamp are so related that the outer generating line MQ of the individual transverse tube sections (4; 20, 21, 22) is substantially straight; the diameter DLQ in the tube bends (5, 6; 23, 24, 25, 26, 27, 28) at the transition between the longitudinal tube sections (2, 3; 16, 17, 18, 19) and the respective transverse tube sections (4; 20, 21, 22) is larger than the diameter DQ of the individual transverse tube sections in the middle thereof, and the diameter DQ of the transverse tube section is at least as large as the diameter DL of the longitudinal tube sections; a depression or dent can be formed at the center of the outer surface of the transverse tube section, and the corners of the transverse tube section can include additional heat dissipating material to further reduce the operating temperature.