US Patent 11085602 LED filament lamp of candle light appearance

A light emitting diode, LED, filament lamp (100), comprising at least one filament (120, 120a, 120b) extending over a length, L, along a longitudinal axis, A, wherein the LED filament comprises an array of a plurality of LEDs (140) extending along the longitudinal axis, and an encapsulant (145) at least partially enclosing the plurality of LEDs, wherein the encapsulant comprises a luminescent material (150), and wherein at least one of the thickness, TL, of the encapsulant along a transverse axis, B, perpendicular to the longitudinal axis, and the concentration, CL, of the luminescent material in the encapsulant, varies over at least a portion of the length, L, of the at least one filament along the longitudinal axis, whereby the color temperature, CTL, of the light emitted from the at least one LED filament varies over the length of the at least one LED filament at least along the portion thereof.