Light emitting diode with improved colour purity

A light emitting diode array comprising:

• a LED layer comprising a plurality of LEDs, each LED configured to emit pump light of a pump light wavelength from a light emitting surface and each LED comprising a plurality of Group III-nitride layers;
• a container layer provided on the light emitting surface of the LED layer, the container layer having a container surface on an opposite side of the container layer to the light emitting surface, the container surface including a plurality of openings each defining a container volume through the container layer to the light emitting surface of the LED layer, each opening and container volume aligned with a respective LED of the LED layer,
• a colour converting layer selectively provided in a container volume, the colour converting layer configured to absorb pump light and emit first converted light of a first converted light wavelength longer than the pump light wavelength;
• a lens provided on the container surface over the opening to the container volume containing a colour converting material, the lens having a convex surface on an opposite side of the lens to the colour converting layer;
• a pump light reflector laminate provided over the convex surface of the lens, the pump light reflector laminate having a stop-band configured to reflect the pump light centred on a first wavelength comprising:
• a first interface layer provided on the convex surface of the lens;
• the first interface layer having a first thickness and a first refractive index, wherein a product of the first refractive index and first thickness is one eighth of the first wavelength;
• a plurality of layers alternating between:
• a low reflectance layer having a second refractive index and a second thickness, wherein the second refractive index is lower than the first refractive index;
• and
• a high reflectance layer having a third thickness and a third refractive index which is higher than the second refractive index, wherein a product of the second refractive index and the second thickness for each of the low reflectance layers is one quarter of the first wavelength, and a product of the third refractive index and the third thickness for each of the high reflectance layers is one quarter of the first wavelength;
• a second interface layer provided on a low reflectance layer of the plurality of layers, the second interface layer having a fourth refractive index and a fourth thickness, wherein a product of the fourth refractive index and the fourth thickness is one eighth of the first wavelength, and the fourth refractive index is larger than the second refractive index,
• wherein each opening at the container surface has a first characteristic diameter (D0) and each lens has a second characteristic diameter (D1) on the container surface, wherein the first and characteristic diameters satisfy the relationship:
• 0.1 D1<D0<0.8 D1.