the first blocking layer 3 applied thereto consists of substoichiometric nicro x this is followed by the first interface layer 4 of substoichiometric zinc aluminum oxide hereinafter referred to as znalo x which in particular improves the adhesion of the following selective function layer 5 the following selective function layer 5 consists of silver and is covered with another interface layer 6 namely the second interface layer made of the same material as the first interface layer 4 the second interface layer 6 is in turn covered by a second blocking layer 7 which is also made of substoichiometric nicro x like the first blocking layer 3 as an alternative the second interface layer 6 may also be omitted the third interface layer 8 which follows the second blocking layer 7 in the exemplary embodiment and consists of stoichiometric tin oxide sno 2 in the exemplary embodiment is optional in the exemplary embodiment this third interface layer 8 was inserted to improve the mechanical stability i e the abrasion resistance of the system by reducing layer stresses which occur in particular with silicon nitride this layer sequence 11 which is deposited above the first dielectric layer 1 having a low to moderate refractive index wherein this is a low e layer sequence in the exemplary embodiment is covered by a traditional top layer which.