Color-corrected hid mercury-vapor lamp having good color rendering and a desirable emission color

Claim 1

A color-corrected high-pressure mercury-vapor lamp which provides good color rendition of illuminated objects and which also has a commercially desirable emission color, said lamp comprising an arc tube which, when normally operated, emits both visible and ultraviolet radiations, and an outer envelope surrounding said arc tube, a phosphor coating carried on the inner surface of said outer envelope, said phosphor coating substantially comprising three phosphor components, a first of said phosphor components when excited by said ultraviolet radiations having a fluorescent output which is substantially confined to the shorter wavelength region of the visible spectrum and has its peak of emission at from 440 nm to 470 nm, a second of said phosphor components when excited by said ultraviolet radiations having a fluorescent output which is substantially confined to the middle wavelength region of the visible spectrum and has its peak of emission at from 520 nm to 560 nm, and the third of said phosphor components when excited by said ultraviolet radiations has a fluorescent output which is substantially confined to the longer wavelength region of the visible spectrum and has its peak of emission at from 605 nm to 630 nm, the relative wattage outputs of said individual emissions of said first phosphor component and said second phosphor component when measured with respect to the wattage output of said long wavelength emission of said third phosphor component each is from 0.05:1 to 0.4:1, and the total of said emissions of said first and said second and said third phosphor components when combined with said visible emissions from said arc tube as normally operated producing a composite lamp emission which at least approximates a cool-white color and which is positioned at least proximate the black-body line as inscribed on the x,y-chromaticity diagram of the ICI system.