The CIE Standard Illuminant D
65, used for specifying non-luminous object colors as a representative of average daylight, is defined by the relative spectral power distribution and no standard source for realizing the illuminant has been recommended.
A fluorescent lamp simulating the illuminant D
65 was designed by optimizing the metamerism indices (MI's) and the color rendering indices (CRI's) with a combination of three kinds of phosphors. The lamp was developed by coating the phosphor mixture as only a single layer on its inner surface. As initial characteristics, the visible range and the ultraviolet range MI's are in the class BC, the general CRI is about 98, and the special CRI's Ri (i=9.15) are larger than 90.
The lamp characteristics during the lifetime were examined. The lumen maintenance after 1000 hours burning is about 93 per cent. The MI's can be kept in the BC class and the general and the special CRI's during the period are more than 95 and 85, respectively.
The lamp characteristics during the lifetime were examined. The lumen maintenance after 1000 hours burning is about 93 per cent. The MI's can be kept in the BC class and the general and the special CRI's during the period are more than 95 and 85, respectively.
The fluorescent lamp D
65 simulator has better characteristics and is more practical than the JIS Xenon Standard White Source, officially recommended in Japan for the color matching practice.
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