WHITE LIGHT-EMITTING DIODE BASED ILLUMINATION DEVICE Russian patent published in 2014 - IPC H01L33/50 C09K9/00 C09K11/00 

FIELD: physics, optics.

SUBSTANCE: invention relates to a white light-emitting diode (LED) based illumination device. The device includes blue, violet or ultraviolet LED chips and a luminescent coating which uses a luminescent material. The luminescent material is a combination (1), (2), (3) or (4) of a luminescent material A with a blue afterglow and a yellow luminescent material B. The yellow luminescent material B is capable of emitting light when excited with blue, violet or ultraviolet LED chips and/or luminescent material A with a blue afterglow. Combination (1) is a combination of 40 wt % Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ and 60 wt % Y₂O₃·Al₂O₃·SiO₂:Ce·B·Na·P, combination (2) is a combination of 5 wt % Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ + 30 wt % Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ + 15 wt % CaS:Bi³⁺,Na⁺ and 25 wt % Y₂O₃·Al₂O₃·SiO₂:Ce·B·Na·P + 10 wt % Sr₃SiO₅:Eu²⁺,Dy³⁺ + 15 wt % Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺, combination (3) is a combination of 5 wt % Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ + 15 wt % CaSrS:Bi³⁺ + 20 wt % Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ and 15 wt % Sr₃SiO₅:Eu²⁺,Dy³⁺ + 20 wt % Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ + 25 wt % Y₃Al₅O₁₂:Ce, and combination (4) is a combination of 45 wt % Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺ and 55 wt % Y₂O₃·Al₂O₃·SiO₂:Ce·B·Na·P. The LED chips emit blue light in case of combinations (1), (2), (3) and emit violet light in case of combination (4). The illumination device is driven by alternating current with frequency of not less than 50 Hz.

EFFECT: invention improves luminescence stability and reduces the thermal effect.

3 cl, 6 dwg, 3 tbl, 2 ex