Patent ID: 11879600

Abstract:
It is an object of the invention to provide an improved LED filament lamp (10), the LED filament lamp (10) comprising: a transparent envelope (11) provided with a transparent optical structure (12); at least one LED filament (14) enclosed by the transparent envelope (11); wherein the transparent optical structure (12) comprises a plurality of individually spaced prismatic grooves (17) and/or ridges that are at least partly aligned along a projection of the at least one LED filament (14) on the transparent envelope (11); wherein each prismatic groove (17) and/or ridge of the plurality of individually spaced prismatic grooves (17) and/or ridges comprises a refractive facet (171) oriented at a wedge angle (172) between 5 and 50 degrees with a tangent of the envelope (11) at the location of the respective prismatic groove (17) and/or ridge.