UV radiation device
The invention relates to an UV radiation device, comprising an LED comprising a nitridic material which is arranged to emit first UV radiation in a wavelength range of 200 nm-300 nm and a luminescent material doped with at least one of the following activators selected out of the group Eu 2+ , Ce 3+ , Pr 3+ , Nd 3+ , Gd 3+ , Tm 3+ , Sb 3+ , Tl + , Pb 2+ and Bi 3+ , wherein the luminescent material is configured to convert at least a part of the primary UV radiation into secondary UV radiation, the primary UV radiation and the secondary UV radiation having a different spectral distribution.
1. An UV radiation device for generating UV radiation in a wavelength range from 200-420 nm, comprising
an LED comprising a nitridic material which is arranged to emit first UV radiation in a wavelength range of 200 nm-300 nm;
a luminescent material configured to convert at least a part of the first UV radiation into second UV radiation, the first UV radiation and the second UV radiation having a different spectral distribution, wherein the luminescent material has an emission peak in the wavelength range of 300-340 nm;
an encapsulation material for encapsulation of the LED; and
scattering particles that are dispersed in the encapsulation material.
2. The UV radiation device of claim 1 , wherein the nitridic material is selected out of the group (Al,Ga,In)N and BN.
3. The UV radiation device of claim 1 , furthermore comprising a polymer comprising FEP.
4. The UV radiation device of claim wherein the luminescent material is provided in particle form with the particles having an average particle size in the range of 0.1 μm-100 μm, more preferably in the range of 10 μm-50 μm.
5. The UV radiation device of claim 4 , wherein the luminescent material is provided in particle form with the particles being coated by an inorganic material with a band gap of ≥5.0 eV.
6. The UV radiation device of claim 5 , wherein the luminescent material is provided in particle form with the particles being coated by Al 2 O 3 .
7. The UV radiation device of claim 1 , wherein the LED wherein the nitridic material comprises Al x Ga 1-x-y In y N, with 0≤x+y≤1.
8. The UV radiation device of claim 1 , wherein the scattering particles comprise boron nitride.
9. The UV radiation device of claim 8 , further comprising a first surface for mounting of the LED, a second surface opposite to the first surface for exiting the UV radiation during operation of the device, and a UV reflective surface between the first surface and the second surface, and wherein the concentration of the scattering particles in the encapsulation material is graded from a first concentration in a first portion of the encapsulation material to a second concentration in a second portion of the encapsulation material, such that the first concentration is higher than the second concentration, and wherein the first portion is positioned between the reflective surface and a light-emitting surface of the LED substantially parallel to the reflective surface and wherein the second portion is positioned between the second surface ( 311 } and a light-emitting surface of the LED substantially parallel to the second surface.
10. The UV radiation device of claim 9 , wherein only the first portion of the encapsulation material comprises scattering particles.
11. The UV radiation device of claim 7 , wherein the luminescent material comprises luminescent material particles that are dispersed in the encapsulation material or that dispersed in a layer forming a light exit surface during operation of the device.
12. A system comprising a UV radiation device according to claim 11 , the system being used in medical therapy.
13. A system according to claim 12 , further comprising a UV interference filter.
14. The UV radiation device according to claim 11 , wherein the encapsulation material comprises UV transparent ceramic material.