Dornier Medizintechnik Gmbh

Max-planck-gesellschaft Zur F&#xf6;rderung Der Wissenschaften E. V.

Hans Lobentanzer

Klaus Ploog

Harald Eizenhofer

Friedrich Ueberle

Norbert Wiesheu

Wolfgang Stolz

Julien Nagle

Michael Grunewald

Heribert Koch

An arrangement for generating focussed shock waves having two two-dimensional shock wave sources. The sources are of different types. In particular, an electromagnetic shock wave source is used in combination with a piezoelectric shock wave source. The arrangement has applications in no-contact lithotrity.

Combination shock wave source

This invention relates to a sound wave generator with a variable effective aperture angle according to the electromagnetic principle for therapeutic applications and particularly for the contactless smashing of a concrement situated in the body of a living being. The sound wave generator includes a flat coil and a metallic diaphragm which is insulated with respect to the flat coil. The flat coil includes three separately activatable and concentrically arranged coil sections. The sum of the areas of the inner coil section and the center coil section is equal to the sum of the areas of the central coil section and the outer coil section. By means of the varying activation of the coil sections, the aperture of the shock wave source can be changed so that the focus geometry and the peak pressures can be varied for different applications, particularly kidney and gallbladder lithotrity.

Sound wave generator for therapeutic purposes

A multiple quantum well light emitting compositional semiconductor device ch as a laser diode or a light emitting diode has an active region comprising an alternating sequence of layers of well layer material and of barrier layer material. The thickness of the barrier layer and of the adjacent well layers is chosen such that for one type of charge carrier a relatively high probability exists for such charge carriers to be present in the barrier region whereas the other type of charge carriers are localized in the potential wells. In this way it is possible to reduce the probability of non-radiative Auger recombination processes occurring thus reducing the threshold current and increasing the quantum efficiency of the device. This is particularly important since material systems with a small bandgap which lase at long wavelengths suitable for optical fibre transmission normally suffer performance penalties due to non-radiative Auger recombination and these penalties can be substantially reduced by tailoring the layer thicknesses to achieve the described probability distributions.

Light emitting compositional semiconductor device

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Munich, Germany

Hans Lobentanzer