A New Generation Deluxe Fluorescent Lamp—Combining an Efficacy Greater than 80 lm/W with a Color Rendering Index of about 85

Abstract

Koedam and Opstelten showed that a Color Rendering Index (CRI) Ra = 80 can be achieved by a proper choice of the wavelengths and intensity ratios of three spectral bands, each having a width of only five nanometers. The Koedam-Opstelten principle can be applied to fluorescent lamps. Haft and Thornton published data on experimental lamps based on the Koedam-Opstelten principle, and reported 3100 lumens and a CRI of 83 for an F40CW lamp. Calculations on phosphor emission bands showed that fluorescent lamps, according to the Koedam-Opstelten principle, combine good color rendering properties with high luminous efficacy. Here, the research was directed to find stable and efficient phosphors.