Transparent substrate coated with a stack of thin layers

A transparent substrate coated with a stack of thin layers having a single silver-based functional metal layer, said stack of thin layers comprising, starting from the substrate, a bottom dielectric coating, said silver-based functional metal layer and a top dielectric coating, each dielectric coating comprising several dielectric layers, wherein:

• the bottom dielectric coating is in contact with the substrate and comprises, starting from the substrate:
• a series of at least three dielectric layers having increasing refractive indices, a smoothing layer and a wetting layer, wherein a refractive index difference between each pair of successive layers of the series of at least three dielectric layers having increasing refractive indices is at least 0.15,
• the top dielectric coating comprises, in a direction moving away from the substrate:
• a zinc-oxide-based layer and a series of at least two layers having decreasing refractive indices, a refractive index difference between each pair of successive layer of the series of at least two layers having decreasing refractive indices being at least 0.15, said series of at least two layers having decreasing refractive indices being in direct contact with the zinc-oxide-based layer.