A proposed lighting-design space: circadian effect versus visual illuminance

Qi Dai, Wenjing Cai, Wen Shi, Luoxi Hao, Minchen Wei

Research output: Journal article publicationJournal articleAcademic researchpeer-review

45 Citations (Scopus)


Although the effort to fully understand the mechanism of non-visual response is still ongoing, quantitative models have been proposed to evaluate light's circadian stimulus based on the characteristics of light incident on human eyes. With the light-emitting diode (LED) technology providing flexibility in spectral design, it is now possible to tune lighting's circadian and visual effects to suit the uses of different built environments. Therefore, it is important to develop a lighting-design approach that considers both visual and non-visual aspects, and understand what combinations are achievable for general illumination applications. In this work, we propose a lighting-design space that allows the exploration of combinations of circadian effect and brightness (visual lit appearance). To demonstrate the feasibility of this approach, we develop a color-mixing method for four-channel color-tunable LED light sources, and maximize the gamut of the proposed space. This gamut represents the possible design objectives that interior lighting designers can target. As an example of application, we demonstrate that our color-tunable LED solution can be used to dynamically simulate both circadian and visual properties of daylight.
Original languageEnglish
Pages (from-to)287-293
Number of pages7
JournalBuilding and Environment
Publication statusPublished - 1 Sep 2017


  • Circadian effect
  • Daylight
  • Interior luminous environment
  • Light quality
  • Mean room surface exitance
  • Spectral power distribution

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Geography, Planning and Development
  • Building and Construction

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