Indirect luminaire

A luminaire comprising:

• at least one optical chamber delimited by a light exit window and a 5 curved reflective surface extending from the light exit window to a mounting surface extending from the curved reflective surface towards the light exit window, each optical chamber comprising:
• a light source mounted on the mounting surface;
• and a light guide extending across part of the optical chamber, comprising:
• a total internal reflection major surface facing the light exit window;
• a further major surface facing the curved reflective surface, said further major surface comprising a light outcoupling portion comprising a plurality of light outcoupling structures;
• a first edge surface optically coupled to the light source;
• and
• a further edge surface opposite the first edge surface arranged to direct light towards the curved reflective surface;
• wherein:
• the optical chamber has a width (W) defined from a light emission surface of the light source to an end point of the curved reflective surface proximal to the light exit window;
• the light guide has a length (L) between the first edge surface and the further edge surface;
• a ratio between the width (W) and the length (L) is in a range of 2:1-5:1;
• and the light guide is spatially away from the curved reflective surface at a substantial distance (H1) along direction of the mounting surface, wherein the substantial distance (H1) is equal to or larger than thickness of the light guide.