Collimator and collimator arrangement
The invention provides various designs for enabling a non-circular area of collimated light output or to enable tessellation of collimators. In a first aspect, a collimator arrangement comprises a plurality of collimators, each having a circular general outer shape with one or more indentation into the circular general outer shape, wherein each indentation comprises a pair of edges which meet at an internal angle and each indentation defines a pair of external angles where the cut-out meets the general outer shape. The collimators are tessellated with each internal angle adjacent one of the external angles of an adjacent collimator. In another aspect, a collimating optical structure comprises a first section comprising one or more portions of a first collimator lens design with a first diameter and a second section comprising one or more portions of a second collimator lens design with a larger, second diameter. The portions comprise sectors which together form an annular shape around the optical axis with non-constant radius from the optical axis.
1. A collimator arrangement comprising a plurality of collimators, each collimator having in a respective exit window a circular general outer shape with one or more cut-outs into the circular general outer shape, wherein each cut-out comprises a pair of edges which meet at an internal angle and each cut-out defines a pair of external angles where the cut-out meets the general outer shape, wherein each respective collimator is interlocked with at least one adjacent collimator to form a tessellation with the internal angle of one of the one or more cut-outs of the respective collimator being interlocked with one of the exterior angles of the at least one adjacent collimator.
2. An arrangement as claimed in claim 1 , wherein each cut-out defines an internal angle of 80 to 100 degrees.
3. An arrangement as claimed in claim 1 , wherein each collimator comprises a center part, and an outer reflector part, wherein the cut-outs of each collimator are formed in the reflector part.
4. An arrangement as claimed in claim 1 , wherein each collimator comprises a total internal reflection collimator.
5. An arrangement as claimed in claim 1 , wherein each collimator has an entrance opening for receiving light from a respective light source, wherein the entrance opening of each collimator has a portion for directing the light away from a region of the collimator including the one or more cut-outs.
6. An arrangement as claimed in claim 1 , comprising:
four collimators each with a single cut-out and one collimator with four cut-outs; or
four collimators each with two cut-outs; or
two collimators each with four cut-outs, four collimators each with two cut-outs and two collimators each with one cut-out; or
four collimators each with four cut-outs and eight collimators each with two cut-outs.
7. A lighting unit comprising:
a collimator arrangement as claimed in claim 1 and
a respective light source configured to couple light into a light input into each of the collimators.