Phosphor converted light emitting diode, a lamp and a luminaire

Abstract

A phosphor converted Light Emitting Diode (LED), a lamp and a luminaire are provided. The phosphor converted LED comprises a LED, a first luminescent material, a second luminescent material and a third luminescent material. The LED emits a first spectral distribution having a first peak wavelength in the blue spectral range. The first luminescent material absorbs a portion of the light of the first spectral distribution and converts at least a portion of the absorbed light towards light of a second spectral distribution. The second spectral distribution has a second peak wavelength in the green spectral range. The second luminescent material absorbs absorbing a portion of the light of the first spectral distribution and/or a portion of the second spectral distribution. The second luminescent material converts at least a portion of the absorbed light towards lights of a third spectral distribution. The third spectral distribution has a third spectral width and has a third peak wavelength. The third luminescent material absorbs a portion of the light of at least one of the first spectral distribution, second spectral distribution, and the third spectral distribution. The third luminescent material converts at least a portion of the absorbed light towards light of a fourth spectral distribution. The fourth spectral distribution has a fourth spectral width and has a fourth peak wavelength. The third peak wavelength and the fourth peak wavelength are in the orange/red spectral range. The third peak wavelength is smaller than the fourth peak wavelength and the third spectral width is larger than the fourth spectral width.

1 . A device comprising:
 a light source emitting a first spectral distribution having a first peak wavelength in the blue spectral range,   a first luminescent material configured for absorbing a portion of the light of the first spectral distribution and for converting at least a portion of the absorbed light into light of a second spectral distribution, the second spectral distribution having a second peak wavelength in the green spectral range,   a second luminescent material configured for absorbing a portion of the light of the first spectral distribution and/or a portion of the second spectral distribution and for converting at least a portion of the absorbed light into light of a third spectral distribution, the third spectral distribution having a third spectral width and having a third peak wavelength,   a third luminescent material configured for absorbing a portion of the light of at least one of the first spectral distribution, second spectral distribution, and the third spectral distribution and for converting at least a portion of the absorbed light into light of a fourth spectral distribution, the fourth spectral distribution having a fourth spectral width and having a fourth peak wavelength,   wherein the third peak wavelength and the fourth peak wavelength are in the orange/red spectral range, and wherein the third luminescent material comprises particles showing quantum confinement and having at least in one dimension a size in the nanometer range.   
     
     
         2 . The device of  claim 1  wherein the third peak wavelength is smaller than the fourth peak wavelength, and the third spectral width is larger than the fourth spectral width. 
     
     
         3 . The device of  claim 1  wherein the second luminescent material comprises one of a red emitting Eu 2+  phosphor, M 2 Si 5 N 8 :Eu 2+  where M is an alkaline earth metal, and (Ca,Sr)AlSiN 3 :Eu 2+ . 
     
     
         4 . The device of  claim 1  wherein the first luminescent material, second luminescent material, and third luminescent material are mixed in a single layer. 
     
     
         5 . The device of  claim 4  further comprising a gap disposed between the light source and the single layer. 
     
     
         6 . The device of  claim 4  wherein the single layer is a ceramic. 
     
     
         7 . The device of  claim 1  wherein particles of the first luminescent material, second luminescent material, and third luminescent material are dispersed and/or dissolved in a matrix polymer. 
     
     
         8 . The device of  claim 7  wherein the matrix polymer is one of polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, and polycarbonate. 
     
     
         9 . The device of  claim 1  wherein the first luminescent material, the second luminescent material, and the third luminescent material are stacked on the light source. 
     
     
         10 . The device of  claim 9  wherein one of the first luminescent material, the second luminescent material, and the third luminescent material is dispersed in a matrix polymer. 
     
     
         11 . The device of  claim 9  wherein one of first luminescent material, the second luminescent material, and the third luminescent material is disposed in a ceramic layer. 
     
     
         12 . The device of  claim 1 , wherein the third spectral width is larger than 80 nanometers expressed as a Full Width Half Maximum value, and the fourth spectral width is less than 60 nanometers expressed as a Full Width Half Maximum value. 
     
     
         13 . The device of  claim 1 , wherein a wavelength difference between the third peak wavelength and the fourth peak wavelength is greater than 10 nanometers. 
     
     
         14 . The device of  claim 1 , wherein a power of light emitted by the third luminescent material is less than 20% of a power of all light emitted by the device. 
     
     
         15 . The device of  claim 1 , wherein the first luminescent material comprises a green emitting phosphor which is one of garnet Y 3 Al 5 O 12 :Ce 3+ , a SiAlON phosphor or (Lu 0.5 ,Y 0.5 ) 3 Al 5 O 12 :Ce 3+ . or Y substituted with Gd or Al substituted with Ga, or a mixture of garnets.