Disclosed are seven assemblies (130;130a;130b;130c;130';133";130"') which provide thermal insulation. In each assembly spacers (133) form an air layer between the diffusing layer (131) and a transparent plate (132) to block heat transfer to a diffusion layer. The layer and the plate may be connected to the spacers by using either an adhesion layer or heat-pressing. The spacers (138,139a) and the plate (132') may form a single unit. The principal use of the assemblies is in an LCD backlight (100). Such a backlight may include a non-integral mold (163) which is disposed at two opposing sides of a bottom chassis (160) to support the diffusing layer (131).
