Method for using white light source, and white light source

Abstract

Provided are a method for using a white light source, and a white light source, wherein precise control of daily rhythm and pleasant lighting can be safely and easily realized in a place of living such as a general home. An embodiment provides a method for using a white light source. Provided that: amounts of stimulation light emitted from a white light source to the intrinsically photosensitive retinal ganglion cells (ipRGCs) and visual cells of the L cone and M cone, among the visual cells of human, are defined as a melanopic irradiance, an L-cone opic irradiance, and an M-cone opic irradiance, respectively; a ratio of the amounts of the stimulation light is expressed by the following formula (1); and A is the ratio corresponding to the emission spectrum of the white light source, and B is the ratio corresponding to the radiation spectrum of a black body having the same color temperature as the white light source, an amount of stimulation light emitted to the ipRGC is quantitatively changed by changing the emission intensity of the white light source satisfying the following formula (2). Melanopic irradiance/(L-cone opic irradiance+M-cone opic irradiance) (1) 0.88≤A/B≤1.11 (2)