The invention provides a light generating device (1000) comprising an
LED filament (100), wherein the
LED filament (100) comprises a support (105), a group (107) of
solid state light sources (110), and an encapsulant (160), wherein: (I) the
LED filament (100) has a length axis (108) of a first length (LI); (II) the
solid state light sources (110) are arranged on the LED filament (100) over the first length (LI) on the support (105), wherein the
solid state light sources (110) are configured to generate
light source light (111); (III) the encapsulant (160) surrounds at least a portion of each
solid state light source (110) of the group (107) of
solid state light sources (110), wherein the encapsulant (160) comprises a
luminescent material (200) configured to convert at least a portion of the
light source light (111) into
luminescent material light (201); (IV) the light generating device (1000) is configured to generate device light (1001) comprising one or more of (i) the light source light (111) and (ii) the
luminescent material light (201); (V) for each
solid state light source (110) of the group (107) of solid state light sources, it holds that, relative to a first
virtual plane (171) parallel to the length axis (108) and intersecting the solid state light source (110), the encapsulant (160) is asymmetrically configured relative to the first
virtual plane (171).