Luminaire with light guide
A luminaire comprises a light guide having light outcoupling elements at one side and a flat light output surface at the other side, which is visible in use of the luminaire. An array of solid state lighting elements is arranged around the edge of the light guide facing the general light output direction. A respective reflector is associated with each solid state lighting element for reflecting light into the light guide. By providing the lighting elements all facing the general light output direction, they can be formed as a single unit, or as a small number of sub-units, thereby simplifying the manufacture. The design of the reflectors, the positioning of the lighting elements, and the design of the light outcoupling elements together may be used to create an asymmetrical light output beam shape. Actuation of different lighting elements may be used to provide different asymmetric light outputs.
1. A luminaire comprising:
a light guide comprising an edge portion between a first major surface and a second major surface, wherein the first major surface defines light outcoupling elements and the second major surface is a flat light output surface which is visible in use of the luminaire, wherein a general light output direction is normal to the second major surface;
an output reflector facing the first major surface;
an array of solid state lighting elements arranged around the edge portion and each having an optical axis extending along and facing the general light output direction; and
an array of lighting element reflectors, with a respective reflector associated with each solid state lighting element for reflecting light into the light guide.
2. A luminaire as claimed in claim 1 , wherein the array of solid state lighting elements are provided on a flat printed circuit board having an annular or part-annular shape.
3. A luminaire as claimed in claim 2 , wherein the flat printed circuit board has a C-shape, and wherein the solid state lighting elements are placed closer together away from the ends than at the ends.
4. A luminaire as claimed in claim 1 , wherein the edge portion of the light guide has a stepped shape, with each solid state lighting element positioned at a step portion.
5. A luminaire as claimed in claim 1 , wherein the light guide and the array of lighting element reflectors are formed as an integral unit.
6. A luminaire as claimed in claim 1 , wherein the outer shape of the light guide is generally circular or elliptical.
7. The luminaire as claimed in claim 1 , wherein the light outcoupling elements comprise 3-D optical elements or printed white dots.
8. A luminaire as claimed in claim 7 , wherein the light outcoupling elements comprise prismatic elements.
9. A luminaire as claimed in claim 1 , wherein the light guide, excluding the light outcoupling elements, has uniform thickness.
10. A luminaire as claimed in claim 1 , wherein there is an array of more than 1000 light outcoupling elements.
11. A luminaire as claimed in claim 1 , wherein the lighting element reflectors comprise reflectors having a surface in the shape of a Cartesian oval.
12. A luminaire as claimed in claim 1 , wherein there is an array of more than 20 solid state lighting elements.
13. The luminaire as claimed in claim 1 , further comprising a controller arranged to individually control the solid state lighting elements.
14. The luminaire as claimed in claim 1 , wherein the light guide comprises a polymer material selected from polycarbonate, poly(methyl methacrylate) and polyethylene terephthalate.
15. The luminaire as claimed in claim 1 , wherein the luminaire is an outdoor luminaire.
16. A luminaire as claimed in claim 2 , wherein the flat printed circuit board is parallel to the second major axis.