Glossary

Luminaire mounted into the ceiling or wall or other surface so that any visible projection is insignificant.

Polystyrene is an economical material, very popular for diffusers due to rigidity and good to high light transmission. Suitable for indoor use only. Stability agents can be added to improve resistance to yellowing. Molecular structure can be modified to achieve TP(a) and TP(b) ratings.

Low-cost material. Medium-light transmission and tough. Stability agents can be added to improve resistance to yellowing.