LED filament and a lamp

An LED filament comprising:

• a carrier comprising a plurality of LEDs arranged in at least two columns of LEDs, the carrier being light transmissive;
• wherein the plurality of LEDs are grouped into at least two different subsets of LEDs, wherein a first subset of the LEDs is configured to emit light of a first color temperature, CT1, and a second subset of the LEDs is configured to emit light of a second color temperature, CT2, CT2 being different from CT1, the first subset of LEDs is encapsulated by a first encapsulant comprising a first luminescent material, the second subset of LEDs is encapsulated by a second encapsulant comprising a second luminescent material, and the first and second encapsulants are different;
• wherein the LEDs of the at least two different subsets of LEDs are arranged in an alternating intersecting configuration in the at least two columns of LEDs such that each column comprises alternating segments configured to emit light of the first and the second color temperatures, respectively;
• wherein the carrier is reflective and has two opposing surfaces, the at least two columns of LEDs are arranged on a first surface of the two opposing surfaces, and a second surface of the two opposing surfaces comprises at least two columns of LEDs arranged in the same way as the at least two columns of LEDs on the first surface, the at least two columns of LEDs on the first surface being evenly aligned on the first surface of the two opposing surfaces with the at least two columns of LEDs on the second surface of the two opposing surfaces between a proximal end and a distal end of the carrier;
• and
• wherein the at least two columns of LEDs are arranged as a single helix with the alternating segments of the at least two different subsets of LEDs emitting light of the first and the second color temperatures extending along the single helix.