How Does the Mobile Phone PPI Design Affect the Visual Acuity with the Change of Viewing Distance?

Abstract

With the development of display manufacturing technology, the PPI of mobile phone screens has been upgrading. But how the visual acuity of the mobile phone has been changed with the increase of the mobile phone PPI has been the issues of concern among the manufacturers all the time. In this study, we use adaptive method to measure people’s vision acuity level under different viewing distance conditions, so as to explore how mobile phone PPI affects human visual acuity under different distances. This study measured the visual acuity of 15 participants with different visual acuity level, and let them to watch different PPI mobile phones at different distance conditions. This study found that in general, with the increase of mobile phone PPI, the visual acuity of subjects increased. This indicates that the PPI of different mobile phones affects the visual acuity in the process of viewing the mobile phone. Under the view distance within 30 cm, the difference of visual perception threshold between different PPI mobile phones was significant, and the PPI effect of mobile phone disappeared after more than 30 cm. A group of participants whose visual acuity level was 5.0, for example, watch their mobile phone at close range (distance < 30 cm), PPI value fitting curve of mobile phone actual measurement angle is lower than the theoretical value curve; but watch their mobile phone at a far range (distance ≥ 30 cm), the actual PPI value curve approaches the theoretical value curve, showing the optimization effect of the phone PPI on the visual acuity.