Abstract: Low-pressure mercury vapor discharge lamp having a discharge vessel which is sealed in a gastight manner and is formed in such a way that the ends at which the electrodes are located are adjacent. The ends are secured to a lamp cap having a shell accommodating a starter and possibly a capacitor. The shell has guide walls for guiding an inner pair of electrode leads past the starter. The electrode leads, starter leads and capacitor leads terminate near the open end of the shell for ease of connection. The open end is closed by a cover with a snap connection. Current connection pins are adjacent the shell and are aligned with an outer pair of electrode leads for ease of assembly.

Abstract: Low-pressure mercury vapor discharge lamp having a tubular discharge vessel arranged within a lamp envelope. The discharge vessel consists of two, preferably generally helically bent tube parts which are connected together by a coupling joint which intersects the tube parts at a location spaced from their sealed ends remote from the electrodes. A cool area is formed in the discharge vessel near this coupling joint to control vapor pressure.

Abstract: A method of manufacturing a low-pressure mercury vapor discharge lamp having a discharge envelope sealed in a vacuum-tight manner and comprising four substantially parallel co-extending glass tube parts (1,2,3,4), adjacent tube parts (1,2) being connected through a cross-coupling (5) to each other so that during operation of the lamp the major part of each of the tube parts (1,2,3,4) as well as the cross-couplings (5,6,7) are traversed by the discharge.According to the invention, first a cross-coupling (24) is established between a first tube part (20) having a length l.sub.1, which is sealed at one end (20a) and comprises at the other end an electrode (22), and a tube part (18) likewise sealed at one end (18a) having a length l.sub.1 +l.sub.2, which tube part (18) comprises at its other end an electrode (16), the tube part (18) being subdivided at (18b) into two tube parts, one of which has a length l.sub.1 (26) and the other has a length l.sub.2 (27), the tube part having a length l.sub.