Abstract: An illumination unit having at least one LED as light source, the LED emitting primary radiation in the range from 300 to 485 nm, this radiation being partially or completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation of the LED, in which unit the conversion takes place at least with the aid of a phosphor which emits yellow-orange with a peak emission wavelength at 540 to 620 nm and originates from the class of the Eu-activated sialons, the sialon corresponding to the formula Mp/2Si12−p−qAlp+qOqN16−q:Eu2+, where M=Ca individually or in combination with Mg or Sr, where q=0 to 2.5 and p=0 to 3.

Abstract: An illumination unit having at least one LED as light source, the LED emitting primary radiation in the range from 300 to 570 nm, this radiation being partially or completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation of the LED, in which unit the conversion takes place at least with the aid of a nitride-containing phosphor which emits with a peak emission wavelength at 430 to 670 nm and which originates from the class of the Ce-or Eu-activated nitrides, oxynitrides or sialons.

Abstract: Illumination device with at least one LED as light source, the LED emitting primary radiation in the range from 380 to 420 nm, this radiation being partially or completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation from the LED, the conversion taking place at least with the aid of a phosphor which emits over a broad band and originates from the class of the (Eu,Mn)-coactivated halophosphates, the cation M representing one of the metals Sr, Ca, Ba.

Abstract: An illumination unit having at least one LED as light source, the LED emitting primary radiation in the range from 300 to 430 nm, this radiation being completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation of the LED, in which unit the conversion takes place at least with the aid of a phosphor which emits green with a peak emission wavelength at 495 to 540 nm and which originates from the class of the Ce-activated sialons, the sialon corresponding to the formula Mp/2Si12−p−qAlp+qOqN16−q:Ce3+, where M=Ca individually or in combination with Sr, with q=0 to 2.5 and p=0.5 to 3.

Abstract: An illumination unit having at least one LED as light source, the LED emitting primary radiation in the range from 300 to 485 nm, this radiation being partially or completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation of the LED, in which unit the conversion takes place at least with the aid of a phosphor which emits yellow-orange with a peak emission wavelength at 540 to 620 nm and originates from the class of the Eu-activated sialons, the sialon corresponding to the formula Mp/2Si12−p−qAlp+qOqN16−q:Eu2+, where M=Ca individually or in combination with Mg or Sr, where q=0 to 2.5 and p=0 to 3.

Abstract: Neodymium ultraphosphates having the formulaMe.sub.x Nd.sub.1-x P.sub.5 O.sub.14wherein Me represents scandium, gallium, yttrium, indium, lanthanum, cerium, gadolinium, lutetium, thallium and/or uranium, and x is a number between 0 and 0.999, in the form of untwinned crystals, are prepared by heating Nd.sub.2 O.sub.3 and Me.sub.2 O.sub.3 in a vessel consisting of fine gold or of an inert, dense, carbon-based material with an excess of high-purity, anhydrous phosphoric acid or diphosphoric or polyphosphoric acid at a temperature between about 500.degree. and 600.degree. C, until the desired crystal size is achieved and then separating excess phosphoric acid or polyphosphoric acid, as the case may be.

Abstract: A highly doped optical amplifier in the form of a thin layer or fiber wherein the pump light is directed transversely to the surface of the layer or fiber. A transparent substrate is provided underneath the layer or fiber and a solar cell is provided in light receiving relationship to light passing through the layer or fiber on the opposite side of the substrate.