Durchführung für eine Glas-Lichtleiterfaser mit einem Metallgehäuse

摘要

The fibre-optic unit includes a casing (1) enclosing a support (2) on which a photo avalanche diode (3) is mounted. The diode (3) is connected to two conductors (4,5) one of which (4) is in contact via the support (2) whilst the other is connected by a wire (6). The second conductor (5) is insulated by a block of glass (7). A metal box (8) is welded by its frame (9) on to the flange (10) of the support (2). The upper part of the box has a hole (11) in which a ring of enamel (13) holds the fibre (12). A protective sleeve (15) surrounds the fibre (12) and has a part gripping the secondary envelope (18) which surrounds the fibre. The coefficient of expansion of the glass fibre (12) is less than that of the enamel which holds it. This in turn has a lower coefficient of expansion than the metal box (8).