LED filament

A light emitting diode, LED, filament comprising:

• a plurality of LEDs configured to, in operation, emit LED light having a dominant peak wavelength in a blue wavelength range from 420 nm to 490 nm, a violet wavelength range from 380 nm to 420 nm and/or an ultraviolet wavelength range from 100 nm to 380 nm;
• an elongated carrier comprising a major surface on which the plurality of LEDs are arranged;
• a first enclosing structure at least partly enclosing the plurality of LEDs and at least a portion of the major surface, the first enclosing structure comprising a first body being arranged to receive at least some of the LED light emitted by the plurality of LEDs, convey it through the first body and output first LED light;
• and
• a second enclosing structure at least in part enclosing the first enclosing structure, the second enclosing structure comprising a second body being arranged to receive at least some of the first LED light, convey it through the second body and output second LED light, wherein the second body comprises one or more wavelength-converting elements configured such that the second LED light has a different spectral light distribution than the first LED light;
• wherein a thickness, T1, of the first enclosing structure is larger than a thickness, T2, of the second enclosing structure multiplied by two, and
• wherein the second enclosing structure comprises one or more openings (9) each of which permits some of the first LED light to be emitted from the LED filament without first having been conveyed through the second body.