Optics for luminaires

Abstract

An optical element () for use in a luminaire, especially a linear luminaire, for creating a prescribed output light distribution pattern from light emitted by a light source at a predetermined location relative to the optical element (), the optical element () comprising a body including a surface which comprises a faceted structure (), the faceted structure () comprising one or more strips or rows () each comprising a plurality of primary facets (), wherein, for any given strip or row () of primary facets (): (i) each respective primary facet () within the given strip or row () is configured such that it redirects light from a respective input direction associated with that primary facet () into a respective output direction associated with that primary facet (); (ii) each respective primary facet () within the given strip or row () is configured such that light propagating therefrom in a said respective output direction associated with that primary facet () contributes to the prescribed output light distribution pattern; and (iii) the respective primary facets () within the given strip or row () are configured such that: the distribution of the respective output directions associated with the respective primary facets () in the given strip or row () has a random or quasi-random character with respect to the positions of the respective primary facets () in the given strip or row (), and the random or quasi-random character of the distribution of the respective output directions associated with the respective primary facets () in the given strip or row () is defined by a probability density function correlating with the prescribed output light distribution pattern and not with the positions of the respective primary facets () in the given strip or row ().