US 12,188,622 B2
Lighting device
Ties Van Bommel, Horst (NL); and Rifat Ata Mustafa Hikmet, Eindhoven (NL)
Assigned to SIGNIFY HOLDING, B.V., Eindhoven (NL)
Appl. No. 17/787,987
Filed by SIGNIFY HOLDING B.V., Eindhoven (NL)
PCT Filed Dec. 21, 2020, PCT No. PCT/EP2020/087434
§ 371(c)(1), (2) Date Jun. 22, 2022,
PCT Pub. No. WO2021/136708, PCT Pub. Date Jul. 8, 2021.
Claims priority of application No. 20150072 (EP), filed on Jan. 2, 2020.
Prior Publication US 2023/0015999 A1, Jan. 19, 2023
Int. Cl. F21K 9/232 (2016.01); F21Y 103/10 (2016.01); F21Y 113/10 (2016.01); H05B 45/10 (2020.01); H05B 45/20 (2020.01); H05B 45/3577 (2020.01)
CPC F21K 9/232 (2016.08) [H05B 45/10 (2020.01); H05B 45/20 (2020.01); H05B 45/3577 (2020.01); F21Y 2103/10 (2016.08); F21Y 2113/10 (2016.08)] 13 Claims
OG exemplary drawing
 
1. A light emitting device configured to emit light with a total color temperature, CTtot, said light emitting device comprising:
at least one first light emitting diode (LED) filament, and
at least one second LED filament,
wherein each of the at least one first LED filament and the at least one second LED filament comprises an elongated carrier, and an array of light emitting diodes mounted on said carrier, wherein the array of light emitting diodes (LEDs) includes a plurality of groups of LEDs, wherein each group includes at least two different color LEDs, wherein the different color LEDs include red LEDs, blue LEDs and green LEDs; and
a controller for individually controlling said at least one first LED filament and said at least one second LED filament,
wherein said at least one first LED filament is arranged to emit light of a homogeneous color having a first color temperature, CT1, said first color temperature being controllable in a first color temperature range, from CT1low to CT1high,
wherein said at least one second LED filament is arranged to emit light of a homogeneous color having a second color temperature, CT2, said second color temperature being controllable in a second color temperature range, from CT2low to CT2high, and
wherein said controller is configured to change the first and second color temperature by controlling all LEDs of each LED filament, such that all LEDs of a LED filament emit light of the same color temperature therewith controlling said total color temperature, CTtot, from a first total color temperature, CTtot,1, to a second total color temperature, CTtot,2, by independently controlling the first color temperature and the second color temperature according to a preselected control scheme to produce a flame-like appearance of the light emitting device by independently controlling a relative intensity of each LED filament, by controlling a relative intensity of each color LED in the plurality of groups of the array of LEDs in the respective LED filaments, such that a difference between the first color temperature and the second color temperature, ΔCT, is not constant during changing CTtot from CTtot,1, to CTtot,2, wherein the control scheme includes a first stage increasing the difference in the first and second color temperatures, ΔCT, by increasing the first color temperature, while maintaining or reducing, or slightly increasing the second color temperature, and in a second, subsequent stage, reducing the difference in the first and second color temperatures, ΔCT, by maintaining or reducing, or slightly increasing the first color temperature, while increasing the second color temperature.