3波長帯形けい光ランプの照明効果

Abstract

The three-band-type fluorescent lamp (3-Band) has a unique spectral power distribution which has been optimized to increase both the general color rendering index (CRI) and the lamp efficacy and it is sometimes said that the lamp has some particular effects more than estimated from the CRI and the efficacy. These effects of the lamp has been examined from various view points in compariosn with other commercial lamps.Colorimetric calculations show that the 3-Band illumination is not suitable for color discrimination problem though it has practicall no problem, in the color perception of surface colors in the usual environment. The 3-Band has good performance in the color rendition for human complexion, and it becomes more preferred in some aspects under the 3-Band added with the halophosphate phosphor than that of the pure type. The 3-Band has unique effects on the brightness and the visual clarity of illumination compared with the other lamps of not only standard types of cool white and daylight color lamps but also de-luxe lamps which have a higher CRI with the broad band continuous spectral distribution.The authors propose a new numerical expression to distinguish the 3-Band from the other types of lamp. That is the ratio of the power in the three spectral regions (445-475, 525-555, 595-625 nm) to the total power (400-700 nm).