Packaged white light emitting device comprising photoluminescence layered structure
A light emitting device includes a Chip Scale Packaged (CSP) LED, the CSP LED including an LED chip that generates blue excitation light; and a photoluminescence layer that covers a light emitting face of the LED chip, wherein the photoluminescence layer comprises from 75 wt % to 100 wt % of a manganese-activated fluoride photoluminescence material of the total photoluminescence material content of the layer. The device/CSP LED can further include a further photoluminescence layer that covers the first photoluminescence and that includes a photoluminescence material that generates light with a peak emission wavelength from 500 nm to 650 nm.
1. A light emitting device comprising:
a cavity having a cavity floor;
a first Light Emitting Diode (LED) comprising a first LED chip for generating light with a dominant wavelength from 440 nm to 470 nm and a first photoluminescence layer at least partially covering a light emitting face of the first LED chip;
a second LED chip for generating light with a dominant wavelength from 440 nm to 470 nm; and
a second photoluminescence layer covering the first LED and the second LED chip, the second photoluminescence layer comprising a photoluminescence material for generating light with a peak emission wavelength from 500 nm to 650 nm,
wherein the first LED and the second LED chip are mounted on the cavity floor; and
wherein the first photoluminescence layer comprises at least 75 weight percent (wt %) of a manganese-activated fluoride photoluminescence material of a total photoluminescence material content of the first photoluminescence layer.
2. The light emitting device of claim 1 , wherein the manganese-activated fluoride photoluminescence material is selected from the group consisting of: K 2 SiF 6 :Mn 4+ , K 2 TiF 6 :Mn 4+ , and K 2 GeF 6 :Mn 4+ .
3. The light emitting device of claim 1 , wherein the device comprises a Chip On Board (COB) packaged light emitting device comprising a substrate and a peripheral wall, wherein the peripheral wall in conjunction with the substrate define the cavity, and wherein the cavity floor comprises at least a part of the substrate.
4. The light emitting device of claim 3 , wherein the first LED comprises a Chip Scale Packaged (CSP) LED comprising the first LED chip and the first photoluminescence layer.
5. The light emitting device of claim 1 , wherein the device comprises a packaged light emitting device comprising a base and side walls, wherein the side walls in conjunction with the base define the cavity, and wherein the cavity floor comprises at least a part of the base.
6. The light emitting device of claim 5 , wherein the first LED comprises a Chip Scale Packaged (CSP) LED comprising the first LED chip and the first photoluminescence layer.
7. The light emitting device of claim 6 , wherein the first LED comprises a light reflective material for preventing light emission from light emitting side faces of the first LED chip.
8. The light emitting device of claim 7 , wherein the first LED comprises a light transmissive material disposed between the light reflective material and the light emitting side faces of the first LED chip.
9. The light emitting device of claim 6 , wherein the first photoluminescence layer covers each light emitting face of the first LED chip.
10. A light emitting device comprising:
a substrate;
a first Chip Scale Packaged (CSP) Light Emitting Diode (LED) for generating light of a first color temperature; and
a second CSP LED for generating light of a second color temperature;
wherein the first and the second CSP LEDs each comprise:
a respective LED chip for generating light with a dominant wavelength from 440 nm to 470 nm;
a respective first photoluminescence layer that at least partially covers a light emitting face of the LED chip, said first photoluminescence layer comprising at least 75 weight percent (wt %) of a manganese-activated fluoride photoluminescence material of a total photoluminescence material content of the first photoluminescence layer; and
a respective second photoluminescence layer comprising a photoluminescence material for generating light with a peak emission wavelength from 500 nm to 650 nm, wherein the second photoluminescence layer covers the first photoluminescence layer; and
wherein the first CSP LED and the second CSP LED are mounted on the substrate.
11. The light emitting device of claim 10 , wherein at least one of the first CSP LED or the second CSP LED comprises a light reflective material for preventing light emission from light emitting side faces of the LED chip.
12. The light emitting device of claim 11 , wherein at least one of the first CSP LED or the second CSP LED comprises a light transmissive material disposed between the light reflective material and the light emitting side faces of the LED chip.
13. The light emitting device of claim 10 , wherein the manganese-activated fluoride photoluminescence material is selected from the group consisting of: K 2 SiF 6 :Mn 4+ , K 2 TiF 6 :Mn 4+ , and K 2 GeF 6 :Mn 4+ .
14. The light emitting device of claim 10 , comprising a light transmissive material layer covering the second photoluminescence layer.
15. The light emitting device of claim 14 , wherein the light transmissive material layer comprises at least one of a glass layer or a light transmissive polymer film.