The present invention relates to an electric lamp assembly comprising an electric lamp, said electric lamp comprising a lamp vessel (10) comprising a lamp envelope (20), a light-emitting element (12) located within said lamp envelope and a color temperature increasing optical interference filter covering at least a portion of a surface of said lamp envelope, said coating being comprised of a plurality of alternating high and low refractive index layers, said coating having a spectrally broad high reflectance of at least 80 % average in the IR wavelength range between 800 and 1300 nm and of at least 80% average in the UV wavelength range between 300 and 400 nm, a steep decrease of reflectance between 380 nm and 400 nm to a reflectance of 0 to 10 % at a wavelength of 400 nm and a continuously steeper increase in reflectance between 400nm and 800 nm, the reflectance being defined by R 300 -400> 80% average at 300-400; 0 % > R400-500 > 10% at 400-500; 10 % > R500-600 > 20% at 500-600; 20 % > R600-700 > 40% at 600-700; 40 % > R700-800 > 80% at 700-800; R800-1300 > 80% average at 800-1300 and R1300-1800 > 60 % average at 1300-1800. According to the gist of the invention an optical interference filter of the broadband pass type is applied, which causes gradual reflection rather than absorbance of undesired amber to red parts of visible light back to the light-emitting element, thus greatly enhancing the efficiency of the lamp and providing a desirable color temperature. 5 Such an electric lamp assembly is suitable as a lamp having a natural white lighting color for general illumination purposes.
|IPC||H01K 1/ 34 A N|
|Publication status||Published - 3 Jul 2008|