Abstract: Plate-type luminaire comprising a prism plate with a smooth upper plate surface and a prism lower surface formed by a plurality of longitudinal ribs; a cover plate made of translucent material resting on the prism surface; and an optical-waveguide plate on the smooth plate surfaces of the prism plate. The plates are curved continuously in the same direction of curvature, transversely to the longitudinal direction of the longitudinal ribs of the prism plate, at least over most of the plate width, with the longitudinal ribs being located on the inside of the arc of curvature of the prism plate. A reflector plate may be disposed over the waveguide plate, with a smooth or a longitudinally ribbed surface.

Abstract: Plate-type luminaire comprising a prism plate with a smooth upper plate surface and a prism lower surface formed by a plurality of longitudinal ribs; a cover plate made of translucent material resting on the prism surface; and an optical-waveguide plate on the smooth plate surfaces of the prism plate. The plates are curved continuously in the same direction of curvature, transversely to the longitudinal direction of the longitudinal ribs of the prism plate, at least over most of the plate width, with the longitudinal ribs being located on the inside of the arc of curvature of the prism plate. A reflector plate may be disposed over the waveguide plate, with a smooth or a longitudinally ribbed surface.

Abstract: Luminaire having an optical waveguide plate, which has a first light guiding surface, and having a light reflecting area—arranged opposite the latter—of an opaque reflector, which reflects light back into the optical waveguide plate in such a way that at least part of said light emerges from the second light guiding surface facing away therefrom. The light reflecting area has a very large number of reflecting area regions, which extend obliquely with respect to one another and obliquely with respect to the opposite first light guiding surface of the optical waveguide plate.

Abstract: Luminaire having an optical waveguide plate, which has a first light guiding surface, and having a light reflecting area—arranged opposite the latter—of an opaque reflector, which reflects light back into the optical waveguide plate in such a way that at least part of said light emerges from the second light guiding surface facing away therefrom. The light reflecting area has a very large number of reflecting area regions, which extend obliquely with respect to one another and obliquely with respect to the opposite first light guiding surface of the optical waveguide plate.

Abstract: A fuse-element for electric fuses is shaped as a metal strip with one or more zones of diminished cross-section.The temperature rise conditions of the fuse-element and of its zones of diminished cross-section can be established and evaluated in combination and--based on these data--a fuse-element can be designed the temperature distribution characteristics of which include different local peak values and the spots where such peak values develop can be set in a manner that the whole fuse-element consists of two parts as far as the temperature distribution is concerned, i.e. a first part where this distribution is in accordance with a steady state distribution (the highest current value still failing to cause any melting), and a second part where the temperature rise distribution determines the character of the melting process, this being the so-called transient distribution characteristic.

Abstract: A fuse-element for use in an electric network, includes a metal strip including at least one portion having a reduced cross-section, a shunt element of conductive material shunting the portion, bonding means conductively bonding the shunt element to the metal strip and being capable of being released at a temperature higher than a predetermined temperature, the shunt element defining a chamber facing towards the metal strip and being sealed by the bonding means between the metal strip and the shunt element, and a material disposed in the chamber having a boiling temperature below the predetermined temperature and capable of producing an internal gas pressure within the chamber sufficient to break the bond when the material is heated to a temperature higher than the boiling temperature.