goal: collimate light from an IR bulb or other IR source. one possibility: imagine a bunch of narrow tubes in front of an IR bulb (FIG 1). the insides of the tubes are mirrored and have a fresnel lens-like profile (FIG 2). call it the sort of an "inverse" fresnel mirror, call it a "funhouse". narrow tubes toothed items, the insides of which are mirrored. air in the centre. "vertical" parts of the teeth are not mirrored and will let light pass thru. FIG 1. bunch of tubes |