高齢者の文字の読みやすさと所要照度に関するVisibility Levelの観点からの検討

概要

論文の詳細を見る
The recommended illuminance in the Japanese lighting standard (JIS Z 9110) was determined based on Indow and Kawai's experimental study concerning the relationship between illuminance and readability of printed text. As the observers in the experiment were young, the recommended illuminance derived from the experiment cannot be applied directly to older people. To estimate the recommended illuminance for older people, a set of numerical analyses was conducted. We found that the readability scale in the above experimental study correlates with the Visibility Level (VL) defined by CIE publication No.19/21. The luminance difference threshold (ΔL_<min>) derived from the contrast threshold function (C_<th>) of the CIE publication was divided into two parts (ΔL_<af> for foveal adaptation and ΔL_<eq> for veiling luminance), assuming ΔL_<min>=ΔL_<af>+ΔL_<eq>. After considering age factors in each part, the luminance difference threshold function ΔL_<min>^* was reconstructed. Applying the ΔL_<min>^* function to the VL analysis, the recommended illuminance for older people was estimated. The result shows that at least about 700 lx of illuminance may be recommended for older people reading 3-mm high printed characters. The visibility level analysis is a useful method for assessing readability considering age-related effects.
社団法人照明学会の論文
1999-05-01