Patent ID: 7825574

Claim:
A high-efficiency LED-based illumination system with improved color rendering, simultaneously exploiting the color-mixing principle of blue, green and red (RGB mixing) and the principle of converting a primary radiation emitted by an LED into light with a longer wavelength by means of a phosphor which at least partially absorbs this radiation, at least two LEDs being used, of which a first LED emits primarily in the range from 340 nm to 470 nm (peak wavelength), and a second LED emits in the red region at 600 to 700 nm (peak wavelength), wherein the green component is produced by the primary radiation of the first LED being at least partially converted by a green-emitting phosphor, the green-emitting phosphor used being a phosphor from the class of the oxynitridosilicates, having a cation M and the empirical formula M (1−c) Si 2 O 2 N 2 :D c , where M comprises at least 50 mol % of Sr as a constituent D represents an activator comprising Eu, c is within the range of 0.001 to 0.2, and the oxynitridosilicate completely or predominantly comprising the high-temperature-stable modification.