| 摘要 |
An electric lamp includes a lamp vessel which is transparent to visible light and accommodates a light source. The lamp vessel is covered with a combination of a light-absorbing medium and an optical interference film having layers of alternately layers of silicon dioxide and layers of a material with a comparatively high refractive index (e.g. ZrO<SUB>2</SUB>) . The reflection R of the interference film changes from 0.60<=R<=0.95 to 0.40<=R<=0.65 with a step DeltaR in the range 0.2<=DeltaR<=0.45, in a wavelength range 0.95xlambda<SUB>tr</SUB><=lambda<=1.2xlambda<SUB>tr</SUB>. In operation, the electric lamp emits colored light in the transmission mode and has a substantially color-neutral appearance in the off state. |
