26 November 2002 Development of a circadian light source
Author Affiliations +
Solid state lighting presents a new paradigm for lighting - controllability. Certain characteristics of the lighting environment can be manipulated, because of the possibility of using multiple LEDs of different emission wavelengths as the illumination source. This will provide a new, versatile, general illumination source due to the ability to vary the spectral power distribution. New effects beyond the visual may be achieved that are not possible with conventional light sources. Illumination has long been the primary function of lighting but as the lighting industry has matured the psychological aspects of lighting have been considered by designers; for example, choosing a particular lighting distribution or color variation in retail applications. The next step in the evolution of light is to consider the physiological effects of lighting that cause biological changes in a person within the environment. This work presents the development of a source that may have important bearing on this area of lighting. A circadian light source has been developed to provide an illumination source that works by modulating its correlated color temperature to mimic the changes in natural daylight through the day. In addition, this source can cause or control physiological effects for a person illuminated by it. The importance of this is seen in the human circadian rhythm's peak response corresponding to blue light at ~460 nm which corresponds to the primary spectral difference in increasing color temperature. The device works by adding blue light to a broadband source or mixing polychromatic light to mimic the variation of color temperature observed for the Planckian Locus on the CIE diagram. This device can have several applications including: a tool for researchers in this area, a general illumination lighting technology, and a light therapy device.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David B. Nicol, David B. Nicol, Ian T. Ferguson, Ian T. Ferguson, } "Development of a circadian light source", Proc. SPIE 4776, Solid State Lighting II, (26 November 2002); doi: 10.1117/12.469722; https://doi.org/10.1117/12.469722


Evaluation of OLED and edge-lit LED lighting panels
Proceedings of SPIE (September 06 2016)
Energy efficient lighting for the biological clock
Proceedings of SPIE (February 09 2011)
Spectral sensitivity of the circadian system
Proceedings of SPIE (January 25 2004)
Non-visual effects of light: implications for design
Proceedings of SPIE (September 02 2010)

Back to Top