Abstract: Two parts, such as a quartz part and piezo-electric part, are indirectly connected to one another by applying relatively thin metallic layers having a thickness of about 0.5 nm to 55 nm under vacuum conditions onto the surfaces of such parts to be joined and then without ventilation of the vacuum-chamber contacting the free surfaces of such metallic layers with one another under the maintained vacuum conditions whereby a substantially permanent bond is formed between such layer.

Abstract: A method of indirectly connecting two parts, such as an acousto-optical building component composed of lead glass and a piezo electric transducer composed of lead-zirconium titanate, whereby at least one mono-molecular layer (having a maximum thickness of 100 nm) composed of a lead-free glass is directly applied under vacuum onto the surfaces of the parts to be joined and metal layers are then applied under vacuuum onto such glass layer and/or the surfaces to be joined so that when the free surfaces of such free metal layers are brought into contact with one another under vacuum, a bond forms therebetween and such bonds indirectly connect the parts with one another. The glass layer prevents diffusion of atoms or ions from the materials (such as lead) on either side of such layer so that the parts so-joined and/or the bonds so-formed are not impaired in any way.