| 摘要 |
Hermetically sealed circuit, for instance a filter circuit with connection terminals 2, which are led out. A disadvantage of the known hermetically sealed circuits is that they are very sensitive to the temperature gradients, which typically occur at soldering into the bush. Thus, the seal may not be hermetic, when it has been subjected to temperatures above 500 °C. According to the invention, a seal has been provided, which is also hermetic, even though it has been subjected to temperatures above 500 °C. The circuit is characterised in that it is sealed in a silver bush 1, and in that the protruding connection terminals 2 at the ends of the bush 1 are sealed by means of a bevel ring 3 of aluminium oxide, said ring being soldered to the connection terminal 2 and the inside of the bush 1 respectively. By this, a seal is obtained, which is hermetic, also against permeation of helium. In addition to the bevelling 3a, 3b providing space for the soldering material, the bevelling also has the effect that the distance to be covered by e.g. permeating helium will be longer, whereby the risk of permeation will be proportionately smaller, if there is any risk of helium permeation at all. |
