LED-based light sources for light emitting devices and lighting arrangements with photoluminescence wavelength conversion
View Patent ↗An LED-based light source for generating light having a selected dominant wavelength λ ds comprises a package housing a plurality of LEDs consisting of LEDs from first and second wavelength bins. The first wavelength bin comprises LEDs having a dominant wavelength λ d1 that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength λ d2 that is within a second wavelength range. The first wavelength bin can comprise LEDs having a dominant wavelength that is shorter than the selected dominant wavelength while the second wavelength bin comprises LEDs having a dominant wavelength that is longer than the selected dominant wavelength. The wavelength bins and number of LEDs are selected such that in operation the dominant wavelength of the combined light emitted by the source is the selected dominant wavelength. Lighting arrangements and light emitting devices incorporating such light sources are disclosed.
1. An LED-based light source for generating light having a selected dominant wavelength comprising:
a package housing a plurality of LEDs comprising at least one first LED from a first wavelength bin and at least one second LED from a second wavelength bin,
wherein the first wavelength bin comprises LEDs having a dominant wavelength that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength that is within a second wavelength range, and
wherein the first and second LEDs are from wavelength bins selected from the group consisting of: wavelength bins having substantially the same peak luminous flux range; wavelength bins having substantially the same forward drive voltage range and combinations thereof.
2. The light source of claim 1 , wherein the first wavelength bin comprises LEDs having a dominant wavelength that is shorter than the selected dominant wavelength.
3. The light source of claim 1 , wherein the second wavelength bin comprises LEDs having a dominant wavelength that is longer than the selected dominant wavelength.
4. The light source of claim 1 , wherein the wavelength bin and number of LEDs from each wavelength bin are selected such that in operation the dominant wavelength of combined light emitted by the light source is the selected dominant wavelength.
5. The light source of claim 1 , wherein the first and second LEDs are operable to generate blue light of wavelength in a range 450 nm to 480 nm.
6. The light source of claim 5 , and further comprising at least one red LED that is operable to generate red light of wavelength in a range 630 nm to 740 nm and wherein the at least one red LED is housed in the package.
7. The light source of claim 6 , wherein the at least one red LED comprises a plurality of red LEDs comprising at least one first red LED from a first wavelength bin and at least one second red LED from a second wavelength bin, wherein the first wavelength bin comprises red LEDs having a dominant wavelength that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength that is within a second wavelength range.
8. The light source of claim 1 , wherein the wavelength range for each wavelength bin is 2.5 nm.
9. An LED-based light source for generating light having a selected dominant wavelength comprising:
a package housing a plurality of LEDs comprising at least one first LED from a first wavelength bin, at least one second LED from a second wavelength bin, and at least one third LED from a third wavelength bin,
wherein the first wavelength bin comprises LEDs having a dominant wavelength that is within a first wavelength range, the second wavelength bin comprises LEDs having a dominant wavelength that is within a second wavelength range, and the third wavelength bin comprises LEDs having a dominant wavelength that is within a third wavelength range.
10. The light source of claim 9 , wherein the selected dominant wavelength λ ds of the LED-based light source is given by the approximate relationship:
λ
ds
≅
n
1
·
λ
d
1
·
Φ
1
+
n
2
·
λ
d
2
·
Φ
2
+
n
3
·
λ
d
3
·
Φ
3
n
1
·
Φ
1
+
n
2
·
Φ
2
+
n
3
·
Φ
3
where n 1 is the number of first LEDs, n 2 is the number of second LEDs, n 3 is the number of third LEDs, λ d1 is the dominant wavelength of the first LEDs, λ d2 is the dominant wavelength of the second LEDs, λ d3 is the dominant wavelength of the third LEDs, Φ 1 is the radiant flux of the first LEDs, Φ 2 is the radiant flux of the second LEDs and Φ 3 is the radiant flux of the third LEDs.
11. The light source of claim 9 , wherein the wavelength range for each wavelength bin is 2.5 nm.
12. The light source of claim 9 , wherein the first, second and third LEDs are operable to generate blue light of wavelength in a range 450 nm to 480 nm.
13. The light source of claim 12 , and further comprising at least one red LED that is operable to generate red light of wavelength in a range 630 nm to 740 nm and wherein the at least one red LED is housed in the package.
14. The light source of claim 13 , wherein the at least one red LED comprises a plurality of red LEDs comprising at least one first red LED from a first wavelength bin and at least one second red LED from a second wavelength bin, wherein the first wavelength bin comprises red LEDs having a dominant wavelength that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength that is within a second wavelength range.
15. An LED-based light source for generating light having a selected dominant wavelength comprising:
a package housing a plurality of LEDs comprising at least one first LED from a first wavelength bin and at least one second LED from a second wavelength bin,
wherein the first wavelength bin comprises LEDs having a dominant wavelength that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength that is within a second wavelength range, and wherein the selected dominant wavelength λ ds of the light source is given by the approximate relationship:
λ
d
s
≅
n
1
·
λ
d
1
·
Φ
1
+
n
2
·
λ
d
2
·
Φ
2
n
1
·
Φ
1
+
n
2
·
Φ
2
where n 1 is the number of first LEDs, n 2 is the number of second LEDs, λ d1 is the dominant wavelength of the first LEDs, λ d2 is the dominant wavelength of the second LEDs, Φ 1 is the radiant flux of the first LEDs and Φ 2 is the radiant flux of the second LEDs.
16. The light source of claim 15 , wherein the first wavelength bin comprises LEDs having a dominant wavelength that is shorter than the selected dominant wavelength.
17. The light source of claim 15 , wherein the second wavelength bin comprises LEDs having a dominant wavelength that is longer than the selected dominant wavelength.
18. The light source of claim 15 , wherein the first and second LEDs are operable to generate blue light of wavelength in a range 450 nm to 480 nm.
19. The light source of claim 18 , and further comprising at least one red LED that is operable to generate red light of wavelength in a range 630 nm to 740 nm and wherein the at least one red LED is housed in the package.
20. The light source of claim 19 , wherein the at least one red LED comprises a plurality of red LEDs comprising at least one first red LED from a first wavelength bin and at least one second red LED from a second wavelength bin, wherein the first wavelength bin comprises red LEDs having a dominant wavelength that is within a first wavelength range and the second wavelength bin comprises LEDs having a dominant wavelength that is within a second wavelength range.