Platelet for the production of passages with glass-metal solderings

p0001Throughs on the basis of glass / metal fusions for the purpose of hermetic encapsulation of active and passive elements of the electrical engineering and electronics will find a wide range of applications. They are usually made of a supporting body made of metal (PCB) with one or more bores for receiving the glass-made insulating, and from the through conductors, which are made of a glass more or less matched metal alloy. In Fig. 1, a conventional implementation is shown schematically in section, being denoted by 1, the circuit board, with the conductors 2 and 3 with the insulating body.

p0002For melting of the conductor into the hole of the circuit board, all parts are fixed onto graphite plates, and then subjected in a suitable oven under inert gas heat treatment. The glass is softened, the holes filled out fully and combines with the metals to a hermetically sealed insulating.

p0003It is generally unavoidable that the glass bead used also contact with the platen gets under gravity of graphite and so installing the smelting process to carbon particles in the glass surface or attached to these. Such graphite particles may in certain cases, be very distracting as the nickel plating of the bushings, as attach to them metal particles which can degrade the electrical characteristics of the implementation.

p0004Although attempts have been made to avoid this sagging of the normally cylindrical sintered glass bead characterized in that this provides you with a collar that has the purpose to fix the bead during the melting process by binding to the metal wall in position, as shown in FIG. is 2, where 4 the graphite plate and with the 5 a collar containing glass bead is called. In this way, the contact with the graphite plate can be largely avoided.

p0005However, this manufacturing method also has two serious drawbacks:<ul><li>1. a collar pearl is difficult to manufacture than a cylindrical glass bead and</li><li>2. it needs when assembling a special straightening process, making particularly in automated assembly units to aggravating noticeable.</li></ul>

p0006The aim of the present invention is a board for _HPreparation of bushings, which does not have the disadvantages described. This object is a_Pla-tine achieved according to the claims.

p0007Thus, the invention avoids the disadvantages by molding of an abutment in the holes of the board. This abutment prevents the cylindrical Glaspreßling by falls during assembly on the graphite plate and then gets in touch with her. Instead of Glaspreßling always remains, even during the melting process, at a certain distance to the graphite plate, so that the glass can properly begin to melt on the metal conductor.

p0008The forming of the abutment can be done in any suitable manner. Conveniently, the abutment is formed in the production of the stamped part with.

p0009This abutment may be annular or consist of restricting cam, wherein the number of cams is not critical, since a single cam can already fulfill the desired purpose (Fig. 4). The best arrangement consists of three arranged at the lower edge of the hole cams have proven.

p0010In the drawing (FIG. 3), an exemplary embodiment of the invention is shown. Fig. 3a shows a board 1 in section with the inserted into the bore, cylindrical glass bead 6. The glass bead 6 rests on restricting cam 7. Fig. 3b shows a detail of the same board in plan view, from below but without the inserted glass bead 6.