Ultraviolet light-emitting devices and methods
In various embodiments, an illumination device features an ultraviolet (UV) light-emitting device at least partially surrounded by an encapsulant. A barrier layer is disposed between the light-emitting device and the encapsulant and is configured to substantially prevent UV light emitted by the light-emitting device from entering the encapsulant.
1. An illumination device comprising:
a light-emitting device configured to emit ultraviolet (UV) light and having at least two spaced-apart contacts;
a package, wherein (i) at least a portion of the package is disposed beneath the light-emitting device, (ii) the contacts of the light-emitting device are electrically connected to the package, and (iii) the light-emitting device is mechanically attached to a portion of the package;
an encapsulant disposed on the package and at least partially surrounding the light-emitting device; and
disposed between the light-emitting device and the encapsulant, a barrier layer configured to substantially prevent UV light emitted by the light-emitting device from entering the encapsulant.
2. The illumination device of claim 1 , wherein the barrier layer comprises a second encapsulant disposed adjacent to the light-emitting device.
3. The illumination device of claim 2 , wherein the second encapsulant is opaque to UV light emitted by the light-emitting device.
4. The illumination device of claim 3 , wherein the encapsulant is substantially transparent to UV light emitted by the light-emitting device.
5. The illumination device of claim 3 , wherein the encapsulant is opaque to UV light emitted by the light-emitting device.
6. The illumination device of claim 5 , wherein the encapsulant and the second encapsulant comprise the same material.
7. The illumination device of claim 3 , wherein a penetration length of UV light within the second encapsulant is less than 25 μm.
8. The illumination device of claim 3 , wherein a penetration length of UV light within the second encapsulant is less than 10 μm.
9. The illumination device of claim 1 , wherein a penetration length of UV light within the encapsulant is 100 μm or more.
10. The illumination device of claim 1 , wherein the barrier layer comprises a material reflective to UV light emitted by the light-emitting device.
11. The illumination device of claim 10 , wherein the barrier layer comprises aluminum.
12. The illumination device of claim 10 , wherein at least a portion of the encapsulant is substantially transparent to UV light emitted by the light-emitting device.
13. The illumination device of claim 10 , wherein at least a portion of the encapsulant is opaque to UV light emitted by the light-emitting device.
14. The illumination device of claim 1 , wherein the UV light emitted by the light-emitting device has a wavelength of 265 nm or less.
15. The illumination device of claim 1 , wherein the package comprises (i) a submount to which the contacts of the light-emitting device are electrically and mechanically connected, and (ii) disposed below the submount, a surface-mount-device (SMD) package, the submount being electrically connected to the SMD package.
16. The illumination device of claim 15 , wherein the submount is electrically connected to the SMD package via one or more wire bonds.
17. The illumination device of claim 1 , further comprising a rigid inorganic lens disposed above the light-emitting device and at least partially protruding from the encapsulant.
18. The illumination device of claim 17 , wherein the lens comprises at least one of quartz, fused silica, or sapphire.
19. The illumination device of claim 17 , wherein a top surface of the encapsulant is disposed above a bottom surface of the lens by at least 0.05 mm.
20. The illumination device of claim 17 , wherein at least a portion of the encapsulant applies a downward force on the lens toward the light-emitting device.
21. The illumination device of claim 20 , wherein a magnitude of the downward force is greater than 0.1 N.
22. The illumination device of claim 17 , further comprising a thin interface material disposed between the lens and the light-emitting device.
23. The illumination device of claim 22 , wherein the interface material has a thickness less than 5 μm.
24. The illumination device of claim 22 , wherein the interface material comprises silicone.
25. The illumination device of claim 22 , wherein at least a portion of the encapsulant applies a downward force on the lens toward the light-emitting device.
26. The illumination device of claim 25 , wherein a magnitude of the downward force is greater than 0.1 N.
27. The illumination device of claim 1 , wherein the light-emitting device comprises a light-emitting diode.
28. The illumination device of claim 1 , wherein the encapsulant comprises a heat-contractive material.
29. The illumination device of claim 1 , wherein the encapsulant comprises a resin of at least one of polytetrafluoroethylene, polyetheretherketone, or perfluoroalkoxy alkane.
30. The illumination device of claim 1 , wherein the encapsulant comprises epoxy resin.