A method of forming a electromagnetic radiator having cavities of predetermined dimensions involving coating a plurality of wires with an electromagnetic radiator material at predetermined thicknesses, the wires being soluble in a solvent and the radiator material being insoluble in the solvent, forming a bundle of a multiplicity of the coated wires, the coatings on the wires engaging each other, reducing the diameter of the bundle to a smaller predetermined diameter and fusing the coatings together with metallurgical bonds through the reduction thereby uniformly reducing the diameter of each of the coated wires and thicknesses of each of the coatings on the wires in the bundle, slicing partially through the fused bundle at predetermined regular intervals whereby to define the depth of the cavities, chemically removing the wires from inside the coatings whereby to form a foraminous electromagnetic radiator having an array of cavities of predetermined lengths and diameters formed by the drawn coatings. The invention also involves a ribbon made by the process and suitable for use as an incandescent lamp filament.
A radiant device comprising an envelope tube, which tube contains a long axis, and inside the tube, at least one radiant source oriented in the direction of the long axis of the envelope tube which is sealed at both ends, with a metal, electrical connecting part at each end of the envelope tube, and at least one elastic intermediate part which absorbs length changes of the radiant source and which is firmly joined at one end to an electrical connecting part and at the other end to the radiant source, and wherein the intermediate part comprises a molybdenum sheet provided with at least one folding portion having two kink points perpendicular to the long axis.
A light-emitting device comprises a light source in the form of an incandescent filament, a substantial part of which is integrated in a host element having at least one portion structured according to nanometric dimensions. The nano-structured portion is in the form of a photonic crystal or of a Bragg grating for the purpose of obtaining an amplified or increased emission of radiation in the region of the visible.
