Patent ID: 6844976
Filing Date: 2005-01-18
Classification: C03C

Abstract:
1. A heat filter, comprising: a substrate; at least one layer of a infrared reflecting material; and a coating forming an interference filter in the visible range, said coating including at least a first and second stack group, said first stack group including an alternation of a first film and of a second film repeated N times and said second stack group including an alternation of a third film and of a fourth film repeated N times, the first and/or the second film or films being differentiated from the third and/or the fourth film or films respectively by its/their thickness, the first and third films having a thickness L or a multiple of L and being constituted by a first material having a refractive index n N is a whole number ≧3 and H and L are geometric thicknesses, and wherein N, H, L, n said first stack group has an alternation of 0.5L/H/0.5L type, repeated 8 times.