CH678680GA3 - Watch glass mounting - has a deposited metal layer between decorative layer and solder to prevent visible effects of soldering - Google Patents

Abstract

Watch and clock glass assembly of glass or ceramic and similar materials (1), which can be soldered into place has at least one decorative layer (2) which is immediately followed by a layer (3) of metal. The metal layer (3) has a firm adhesive bonding with the decorative layer (2) on one side, and a high affinity to the solder (4) on the other side. The metal layer (3) is applied to the decorative layer (2) by a combination of physical vacuum cladding and electro-chemical processes. The cladding is structured so that, on soldering, there are no visible effects of alloying or diffusion on the thin metallic decorative layer (2) over the soldering zones. The adhesion between the metal layer and the decorative layer is stronger than the adhesion of the soldering. The layer (3) applied directly to the decorative layer (2) is pref. a partly oxidised metal with a high oxygen affinity such as Ni, Cr or Ti. It is applied by a vacuum cladding process to give a thickness of a few nanometers. The layer (3) to give a high affinity to the solder can also be of Ag, Bi, Au, Cu or In, or combinations. A ring or body of some other geometric form, as a structural component which is larger than the watch glass (1), or the same size or smaller, is of steel, coloured metal or Au, soldered into place. ADVANTAGE - The structure gives a watch and clock glass or housing which can be assembled easily and economically and, after soldering, shows no signs of the bonding action.