A flexible LED filament configured for emitting omnidirectional light, comprising: a linear array of LED chip (402, 404) operably interconnected to emit light upon energization; a conductive electrode (410, 412); a plurality of conductive wires for electrically connecting the linear array of LED chips and the conductive electrode; and a light conversion coating enclosing the linear array of the LED chip and a portion of the conductive electrode, wherein: the light conversion layer includes a top layer and a base layer interconnecting conformally to form a unitary enclosure; the top layer is coated on and contacts the linear array of LED chips, the base layer and the conductive electrode; characterized in that the base layer includes a phosphor film layer and a base transparent layer, the phosphor film layer being disposed between the linear array of the LED chips and the base transparent layer, the hardness of the phosphor film layer being harder than the base transparent layer, the phosphor film layer comprising phosphors, inorganic oxide nanoparticles and an adhesive binder wherein the amount of the phosphors is greater than the adhesive binder, the top layer includes a phosphor glue layer and a top transparent layer, the phosphor glue layer being disposed between the linear array of the LED chips and the top transparent layer, wherein the linear array of LED chips and the conductive electrode are interposed between the base layer and the top layer, and the base layer is harder than the top layer. a linear array of LED chip (402, 404) operably interconnected to emit light upon energization; a conductive electrode (410, 412); a plurality of conductive wires for electrically connecting the linear array of LED chips and the conductive electrode; and a light conversion coating enclosing the linear array of the LED chip and a portion of the conductive electrode, wherein: the light conversion layer includes a top layer and a base layer interconnecting conformally to form a unitary enclosure; the top layer is coated on and contacts the linear array of LED chips, the base layer and the conductive electrode; characterized in that the base layer includes a phosphor film layer and a base transparent layer, the phosphor film layer being disposed between the linear array of the LED chips and the base transparent layer, the hardness of the phosphor film layer being harder than the base transparent layer, the phosphor film layer comprising phosphors, inorganic oxide nanoparticles and an adhesive binder wherein the amount of the phosphors is greater than the adhesive binder, the top layer includes a phosphor glue layer and a top transparent layer, the phosphor glue layer being disposed between the linear array of the LED chips and the top transparent layer, wherein the linear array of LED chips and the conductive electrode are interposed between the base layer and the top layer, and the base layer is harder than the top layer. the light conversion layer includes a top layer and a base layer interconnecting conformally to form a unitary enclosure; the top layer is coated on and contacts the linear array of LED chips, the base layer and the conductive electrode; characterized in that the base layer includes a phosphor film layer and a base transparent layer, the phosphor film layer being disposed between the linear array of the LED chips and the base transparent layer, the hardness of the phosphor film layer being harder than the base transparent layer, the phosphor film layer comprising phosphors, inorganic oxide nanoparticles and an adhesive binder wherein the amount of the phosphors is greater than the adhesive binder, the top layer includes a phosphor glue layer and a top transparent layer, the phosphor glue layer being disposed between the linear array of the LED chips and the top transparent layer, wherein the linear array of LED chips and the conductive electrode are interposed between the base layer and the top layer, and the base layer is harder than the top layer.