Abstract: An optical element particularly elements of IR optics comprises a system of a plurality of infrared transmitting optically effective thin layers of substances. The substances are chosen from the group: germanium, zinc selenide, zinc sulfide, chalcogenide glasses, thorium fluoride, yttrium fluoride, and praseodymium fluoride. The layers are applied to an infrared transmitting substrate of a material of the group: germanium, zinc selenide, zinc sulfide and chalcogenide glasses. An intermediate layer is disposed between the thin layers and the infrared transmitting substrate and this has a maximum thickness of 100 nm and comprises a material of the group: hafnium oxide, yttrium oxide, and scandium oxide.

Abstract: An electrochromic coat system comprises first and second juxtaposed spaced apart transparent plates and first and second spaced apart transparent electrodes adjacent respective ones of said plates and spaced apart from each other including a plurality of electrochromic coats between the electrodes and a polyvalent metal having free atoms embedded between one of the electrochromic coats and the electrodes. The coats include at least one coat of an electrochromic metal and at least one additional transparent coat of a matrix of solid inorganic substance which comprises an electrolyte carrier. An electrochromic metal comprises, for example, WO.sub.3. One additional coat acts as a matrix of solid inorganic substance (SiO.sub.2 or ZrO.sub.2) which acts as a carrier of an electrolyte which is arranged between the two electrodes. One of the two electrodes is transparent.