Abstract
First, basic knowledge of light and vision, photometry, history of daylighting and artificial lighting are shown in this article. Second, lighting requirements for indoor environment are described based on the parameters which are specified in JIS Z 9125“Lighting of Indoor Work Places”. Luminance distribution, illuminance, glare, directionality of light, color of light and color rendering are included. Moreover, daylight in indoor environment is discussed regarding change in its amount, spectral distribution, effect of direct sun light and psychological effects of daylight and windows. Finally“light and Low-carbon society”and“light and health”are presented. The effect of several strategies to reduce CO2 emission due to indoor lighting is simulated, e. g. if all incandescent lamps are replaced by LED, reduction of CO2 emission can reach 4 million ton which equals a target value. As health effect of light, suppression of melatonin secretion, which shows a circadian rhythm, by light was also discussed.
