Lighting device housing, luminaire and method of manufacture

1. A housing for a lighting device, wherein the housing comprises an elongate base region and opposing elongate sidewalls extending from opposite elongate sides of the elongate base region towards respective terminal ends, wherein each of the opposing elongate sidewalls has an optically transmissive inner surface separated from an outer surface by a distance of 5 millimeters or less to form a cavity for housing a reflective foil or a thermally conductive member, wherein the inner surface extends across the elongate base region, and wherein the inner surface comprises a recess in the elongate base region for housing a light engine, wherein the housing further comprises a light exit window extending across the respective terminal ends of the opposing elongate sidewalls distal to the elongate base region.

2. The housing according to claim 1 , wherein the housing is made of a polymer or polymer blend.

3. The housing according to claim 1 , wherein the light exit window is double-skinned such that the cavity extends into the light exit window.

4. The housing according to claim 3 , wherein the light exit window carries a pattern of beam shaping elements for shaping a luminous output emanating from the elongate base region.

5. The housing according to claim 1 , wherein the cavity in the opposing elongate sidewalls and the recess in the elongate base region are interconnected to form a single cavity that extends across the opposing sidewalls and the elongate base region.

6. The housing according to claim 1 , wherein the recess comprises a first elongate surface portion adjoining a further elongate surface portion along the elongation direction of the elongate base region under a non-zero angle.

7. The housing according to claim 1 , wherein the housing has a parabolic cross-section in a direction perpendicular to the elongation direction of the elongate base region.

8. The housing according to claim 1 , further comprising a plurality of joins extending across the housing in a direction perpendicular to the elongation direction of the elongate base region.

9. A luminaire comprising the housing according to claim 1 and at least one light engine housed in the recess of the elongate base region.

10. The luminaire according to claim 9 , wherein the at least one light engine comprises an elongate strip carrying a plurality of said light engines.

11. The luminaire according to claim 9 , wherein the luminaire further comprising at least one of:

a reflective foil extending into the cavity located within the opposing side walls;

a thermally conductive member extending into the cavity located within the opposing side walls; and

a diffuser foil in a double-skinned light exit window extending across the respective terminal ends of the opposing elongate sidewalls distal to the elongate base region.

12. The luminaire according to claim 9 , wherein the luminaire comprises a plurality of said housings neighboring each other in a direction perpendicular to the respective elongation directions of said housings.

13. A method of manufacturing the housing according to claim 1 , wherein the method comprises the steps of:

providing a 3-D printing apparatus comprising an extruder nozzle having at least one filament feeder for feeding a preformed filament through the extruder nozzle;

3-D printing a plurality of abutting filaments with the 3-D printing apparatus, each of said printed filaments defining a portion of the housing including a section of the inner surface and the outer surface, said portion extending in a direction perpendicular to the elongation direction of the housing.

14. The method according to claim 13 , wherein the extruder nozzle has a plurality of filament feeders, and wherein the step of 3-D printing comprises printing at least some of the abutting filaments in parallel.