@phdthesis{discovery10204586,
            year = {2025},
          school = {UCL (University College London)},
           month = {February},
           title = {The effects of spectral power distribution with high melanopic efficiency on visual and atmosphere perceptions of offices},
            note = {Copyright {\copyright} The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author's request.},
          author = {Zhao, Chengpeng},
        abstract = {Recent investigations into the effects of spectral power distributions (SPD) have largely kept
separate the impact on the human's circadian system from impressions of interior lighting.
When daylight is insufficient, blue-enriched electric light sources are considered as an
alternative to deliver a stronger stimulus to circadian system of occupants in offices. However,
such light sources may not always be desired. At present, it is still not clear how to balance the
non-visual effects of light on circadian rhythm and user satisfaction of office lighting.
Therefore, this research aims to explore the influences of SPD with high Melanopic Daylight
Efficacy Ratio (M-DER) on visual and atmosphere perceptions in the context of Integrative
Lighting design for offices. Three objectives were proposed to achieve this aim. The first
objective seeks to test can cold white light sources be more acceptable if they have SPDs closer
to the daylight. The second objective is to examine if increasing melanopic efficiency by
shifting peak wavelength of blue primary affects visual and atmosphere perceptions. The third
objective is to explore how Duv affects atmosphere perceptions of office lit by SPDs with
melanopsin stimulating peak wavelengths.
Three psychological experiments were conducted with a multi-channel LED lamp which can
closely resemble the SPD of daylight. The results suggest neither using SPD of daylight nor
changing Duv improve user satisfaction of electric lighting. Metameric approaches can
increase melanopic efficiency of SPD without significantly affecting visual and atmosphere
perception, but the colour matching functions should be selected with care. There was evidence
suggesting melanopsin may play a role in colour vision. It is anticipated that these results will
assist lighting designers and manufacturers in selecting the most beneficial light spectra for the
health and well-being.},
             url = {https://discovery.ucl.ac.uk/id/eprint/10204586/}
}