Legible Character Size on Mobile Terminal Screens: Estimation Using Pinch-in/Out on the iPod Touch Panel

  • Satoshi Hasegawa
  • Masako Omori
  • Tomoyuki Watanabe
  • Shohei Matsunuma
  • Masaru Miyao
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5618)


Using a multi-touch display on an iPod touch mobile multimedia player, an evaluation experiment was conducted to determine the most legible size for characters displayed on screens of mobile terminals. Subjects enlarged the characters by pinch-out (pinch opening) and/or reduced them by pinch-in (pinch closing) on a multi-touch display with more than one finger, and adjusted to the sizes of alphanumeric or Japanese characters to be the most legible. The characters were displayed positively (black characters on a white background) or negatively (white characters on a black background) using graphic text on the iPod touch. The adjusted sizes of characters and viewing distances were measured and visual angles were calculated. The influence of the positive or negative image display mode and the age of subjects on these legibility parameters is described.


Readability Visibility Small Display Character Aging Effects 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Satoshi Hasegawa
    • 1
  • Masako Omori
    • 2
  • Tomoyuki Watanabe
    • 3
  • Shohei Matsunuma
    • 4
  • Masaru Miyao
    • 5
  1. 1.Department of Information MediaNagoya Bunri UniversityInazawa AichiJapan
  2. 2.Faculty of Home EconomicsKobe Women’s UniversitySuma-ku KobeJapan
  3. 3.Faculty of Psychological and Physical ScienceAichi Gakuin UniversityAichiJapan
  4. 4.Nagoya Institute of TechnologyShowa-ku NagoyaJapan
  5. 5.Graduate School of Information ScienceNagoya UniversityChikusa-ku NagoyaJapan

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