高齢者の視覚特性に適合した液晶ディスプレイの文字表示条件 表示輝度，コントラスト，文字サイズの主観的な適正値の若齢者との比較

Abstract

We investigated the influence of age-related changes in vision on optimum display luminance, contrast, and character size of transmissive liquid crystal displays (LCDs). Young (28 persons with a mean age of 21.7 years) and old (28 persons, mean age of 68.1 years) subjects rated the subjective legibility and preference of 25 luminance and contrast combinations for five character sizes which were displayed on a TFT-LCD. The preferred angular character size for a display luminance of 80 cd/m2 was 33 minutes for old subjects and 32 minutes for young subjects. Display luminance requirements for subjective legibility in old subjects were twice as high as for young subjects. However, the actual display luminance preferred by old subjects was 130% of that by young subjects. These results indicate that old subjects must select a higher display luminance to maintain legibility. This may be due to an age-related reduction in visual contrast sensitivity in lower luminance conditions.