Mercury-free high pressure discharge lamps dominated by molecular radiation

Abstract

High intensity discharge (HID) lamps dominated by molecular radiation offer a very promising alternative for use in future light sources. They are able to deliver competitive efficacies of about 110 lm W −1 and higher, excellent colour rendering index above 90 and a correlated colour temperature in the 3000–4000 K region at the operating point near the Planckian locus. Moreover, these lamps are opening up the possibility of dimming. Due to the fact that they are able to omit mercury they are environmentally friendly. The emission spectra generated by these HID lamps differ significantly from those of conventional lamps. The reason for this is the dominance of molecular radiation processes. In comparison with conventional HID lamps atomic contributions are usually rather small. In the present case they amount to less than about 10% of the total intensity in the visible range.