Shaped fluorescent light tube e.g. for illuminated advertising sign, has internal spiral of glass with high melting point and outer glass tube with lower melting point shaped by application of heat

摘要

The fluorescent light tube has a spiral element made of a glass with a relatively high melting point, contained within a light tube made of a glass with a relatively low melting point, which is heated at a required point to allow it to be shaped, the spiral element preventing its implosion.