Readability of characters on mobile phone liquid crystal displays

Subject performance in reading characters on mobile phone liquid crystal displays was researched by using (a) English sentences with 3 or 4 different sizes of characters on 2 types of displays with different resolutions (n=23; age=31.6+/-6.0 years), (b) Japanese characters in 3 different sizes and 2 types of font (n=98; age=44.5+/-18.5 years), and (c) Japanese characters vertically enlarged 1-4 times (n=120; age=46.9+/-18.6 years). Subjective evaluation, reading speed, number of reading errors, and viewing distance were recorded. Readability was higher with higher resolution displays, and with Gothic than with Mincho font in Japanese. Young subjects shortened the viewing distance as characters became smaller, whereas elderly subjects increased the viewing distance irrespective of the size of characters. Characters of 3-5 mm are appropriate for the young but inadequate for the elderly. Readability of Japanese characters improved when they were vertically enlarged to approximately twice the width.