生活行為に求められる明るさと色味に関する研究

<p> The purpose of this study is to provide a comfortable lighting environment corresponding to age and life activities. The required illuminance and correlated color temperature (CCT) differs by age. In this paper, we think that the main cause of this is a change in feeling of brightness and color with aging and that there is no major difference in an allowable brightness and color for a life activity by age. We examine this based on the result of the subjective evaluation experiment. Eight people are included in each age group. The experimental range of illuminance is 30–950 lx and that of CCT is 2900–5200K. We take up five life activities in daily life (reading newspapers, eating, getting-together, relaxing, and sleeping).</p><p> The main findings are as follows:</p><p> 1) When they can permit a color, the relations between brightness and its acceptable level is different between life activities. However, they are approximately matched between age groups in every life activity.</p><p> 2) When they can permit a brightness, the relations between color and its acceptable level is different between life activities. However, for the elderly, a change of the acceptance level is small due to an apparent of color in each life activity.</p><p> 3) There is a common range of brightness and apparent color between the young and the elderly which are evaluated acceptable or almost-acceptable. Brightness is required for activities with a high degree of visual work, and color is required for activities with a high degree of relaxation. Furthermore, we grasp a difference between age groups regarding interaction of illuminance and correlated color temperature for inducing a feeling of brightness and color.</p><p> 4) As for a brightness, in the case of low illuminance, the lower CCT, the brighter the young feel. On the other hand, in the case of high illuminance, the lower CCT, the darker they feel. For the elderly, the lower CCT, the brighter they feel regardless of illuminance.</p><p> 5) As for an apparent color, the lower illuminance, the more they feel colored regardless of CCT. For the elderly, in contrary to the young, the higher illuminance is, the more they feel colored, but there is no clear difference.</p><p> In this paper, we clarify that there is an almost-allowable brightness and color for both age groups in each activity. This enables planning of illuminance and CCT suitable for life activities by setting age as an explanatory variable for a general index of the sensitivity of eyes and clarifying a relationship between illuminance and CCT, and a feeling of brightness and color, quantitatively in future.</p>