A New Generation of “Deluxe” Fluorescent Lamps, Combining an Efficacy of 80 Lumens/W or More with a Color Rendering Index of Approximately 85

It has been shown previously that color‐rendering capability and luminous efficacy of fluorescent lamps depend on the spectral composition of the emitted light. Three spectral regions appear to be of special interest, the blue at 450 run, the green at 540 nm, and the orange‐red at 610 nm. Among the hexagonal aluminates blue‐emitting and green‐emitting , together with orange‐red‐emitting are particularly suited in a new generation "deluxe" fluorescent lamps. Lamps with a color temperature >2350°K can be made. The efficacy of the lamps ranks from approximately 82 lm/W at 3000°K to 80 lm/W at 6000°K. The color‐ rendering index is 81–85. A small increase of is achieved when Mn2+ is incorporated in , giving rise to an additional green emission at 515 nm. The new blend is compared to other blends and further prospects in fluorescent lamp developments are outlined.