||Although the concept of the first helical compact fluorescent lamp was developed and proven by GE's Ed Hammer as early as 1976, it took a further two decades before the first products were launched. The first lamps were shaped by manual glassblowing techniques, and it proved extremely challenging to develop a high speed automatic machine to take over the process, such that lamps could be produced at a price that the market would accept. GE came close to launching the Heliax lamp in 1996 - a 32W non-integrated lamp intended for professional lighting applications which was unveiled at the World Light Fair in Hannover, but at the last minute it was withdrawn due to production problems. Meanwhile the manufacture of spiral-shaped CFLs took off in China, where the high labour content was more affordable.
A decade later, GE tried again to develop a mechanised process to form the spiral tube, and set up a pilot production plant at its Hungarian Tungsram. The lamp featured on this page was the result. It was produced only in this powerful 42W rating, the larger size lamps benefitting the most from the compact helical shape. Its high luminous flux was the first able to replace the 120V 150W incandescent lamp while maintaining a length sufficiently short to fit the standard 6.5" harp-support of American lampshades.
The glass tube has been first blow-moulded to produce the large cold chamber at the top of the spiral. The rest of the spiral is unusual for its variable diameter, producing a more spherical rather than cylindrical shaped body for better light extraction and distribution, and for its in-line electrodes that minimise tube length. The lamp proved expensive however, and was soon replaced by a hand-made Chinese product.