Fluorescent material as a radiation source in an apparatus for artificial weathering

An apparatus for artificial weathering or lightfastness testing of samples or for simulating solar radiation, the apparatus comprising:

• a weathering chamber;
• an ultraviolet (UV) light source provided in the weathering chamber, the UV light source consisting of a plurality of UV light emitting diodes (LEDs), each one of the plurality of UV LEDs comprising a specific maximum emission wavelength;
• a fluorescent material arranged to be radiated by a UV radiation emitted by the UV light source, the fluorescent material being configured to emit a fluorescent radiation comprising spectral emission characteristics similar to natural solar radiation;
• and
• a transparent layer, the fluorescent material being applied directly to the transparent layer in the form of a thin layer, wherein:
• a layer configured to filter excessive infrared light emitted by the fluorescent material is directly disposed on one main surface of the transparent layer,
• the transparent layer is in a shape of a cylinder,
• the UV light source is arranged in an inner space of the cylinder, and
• the apparatus is configured to rotate the samples around the fluorescent material.