中文摘要：

目的研究手机触屏中两个相邻按键之间的最小中心距离。方法记录不同按键中心距条件下，四个典型任务情景下（拇指离散、食指离散、拇指系列和食指系列）的输入操作绩效和主观评价结果，并由绩效结果来动态调整下一轮操作需要的按键中心距，反复循环直至获取最小中心距。结果拇指离散、拇指系列、食指离散和食指系列四个任务下的最小按键中心距分别为：4．17mm、6．30mm、3．38mm和5．40mm。结论研究中以按键中心距参数代替按键尺寸和按键间距这两个参数的方法不仅保证了界面设计的简单高效，而且研究结果同时兼顾了稳定性和用户任务操作上的差异性。因此，研究结果可以为以手机为代表的小型触屏界面中的按键及其布局的标准化设计提供科学依据。

英文摘要：

Objective The current study investigated the central key- to- key distance, which was defined as the distance between the central points of two adjacent soft keys on touch - screen. Methods To determine the shortest key -to -key distance, participants were asked to finish a series of input tasks on a touch keyboard,when the input accuracy and subjective evaluation were recorded. The central distance remained constant within each block. The distance would change across blocks according to participants＇ key input accuracy. Results The shortest central distance was 3.38mm for the forefinger single input condition; 4.17mm for the thumb single input condition; 5. 40ram for the forefinger continuous input condition ; 6.30mm for the thumb continuous input condition. Conclusion The results indicated that key- to- key distance is an efficient parameter,which can make the interface design much simpler, and the research results give both consideration to the stability and the users＇ operation difference. In summary, this study provides empirical evidences for a standard soft key design in small touch screen interactions.