Abstract: An efficient fluorescent lamp of high brightness and compact size is provided by forming the envelope from vitreous tubing that is bent into three U-shaped sections which are disposed in mutually perpendicular planes and define a single convoluted discharge channel. The U-shaped sections are so oriented that the legs of the U's are disposed in quadrangular columnar array with the ends of the tubing located adjacent one another and opposite one of the U-bends. Conventional electrode-stem assemblies are sealed into the ends of the bent tubing and the sealed legs are coupled to each other and the proximate U-bend by brace means which rigidifies the multi-section envelope. An efficient method of manufacturing the envelope employing a pair of arcuate molding components and two bending operations that form the three U-bends with only a single tibe-heating operation is also disclosed.

Abstract: An efficient fluorescent lamp of high brightness and compact size is provided by forming the envelope from vitreous tubing that is bent into three U-shaped sections which are disposed in mutually perpendicular planes and define a single convoluted discharge channel. The U-shaped sections are so oriented that the legs of the U's are disposed in quadrangular columnar array with the ends of the tubing located adjacent one another and opposite one of the U-bends. Conventional electrode-stem assemblies are sealed into the ends of the bent tubing and the sealed legs are coupled to each other and the proximate U-bend by brace means which rigidifies the multi-section envelope. An efficient method of manufacturing the envelope employing a pair of arcuate molding components and two bending operations that form the three U-bends with only a single tube-heating operation is also disclosed.

Abstract: The light output of a fluorescent lamp is improved under cold temperature operating conditions by enclosing the envelope in a jacket of light-transmitting plastic material that has a plurality of air pockets or bubbles formed therein. The pockets of entrapped air collectively function as a thermal blanket for the envelope which conserves the heat produced by the lamp during operation without obstructing the generated light rays. The "thermo-bubble" jacket is preferably fabricated from flexible two-ply plastic so that it can also serve as a lightweight protective component for the lamp when it is packed with other jacketed lamps in a shipping container.