White LED spectra for general lighting should be designed for high luminous efficacy as well as good color rendering. Multichip and phosphor-type white LED models were analyzed by simulation of their color characteristics and luminous efficacy of radiation, compared with those of conventional light sources for general lighting. Color rendering characteristics were evaluated based on the CIE Color Rendering Index CRI, examining not only Ra but also the special color rendering indices Ri, as well as on the CIELAB color difference Eab for the 14 color samples defined in CIE 13.3. Several models of three-chip and four-chip white LEDs as well as phosphor-type LEDs are optimized for various parameters, and some guidance is given for designing these white LEDs. The simulation analysis also demonstrated several problems with the current CRI, and the need for improvements is discussed. © 2005
[1]
James A. Worthey,et al.
Color Rendering: Asking the Question
,
2003
.
[2]
L. E. Barbrow.
International Lighting Vocabulary
,
1964
.
[3]
W. A. Thornton.
A Validation of the Color-Preference Index
,
1974
.
[4]
Lei Deng,et al.
Color rendering properties of LED light sources
,
2002,
SPIE Optics + Photonics.
[5]
Y. Nayatani,et al.
Visual clarity and feeling of contrast
,
1994
.
[6]
D. Nickerson.
Technical Note: 1963 CIE Interim Method of Measuring and Specifying Color Rendering of Light Sources
,
1964
.