Ergonomic Study On The Matching Between Touch-screen Mobile Phone Sizes And Users’ Hand-type Sizes

In recent years, the intelligent touch-screen mobile phone has gradually replaced thetraditional keyboard mobile phone to become the main trend product of mobile phone industry.Today, on the market, the touch-screen mobile phones are usually in the3.0-7.0inches size rangein which the range of4.0inches and above is dominant. On the other hand, considering thelimited hand size of users, how to make the increasing phone size to match it has naturally poseda major problem. However, the previous research in this area is limited to a small amount ofqualitative research only and lacks a large amount of quantitative research. Therefore, this studyis aimed at providing some more insights by conducting a quantitative research. It simulated themobile phone’s common function through a serial target pressing task, and then explored thematching between users’ hand-type sizes and touch-screen mobile phone sizes by theexperimental methods which include operation performance test, surface electromyogram andsubjective evaluation.This research contains a sampling surveying investigation and four laboratory experiments.In investigation1, we made a sample survey of250university students’ hand-type sizes andanalyzed the categories and the distribution of their hand-type sizes. The result provided thebasic principle for experiment1~4to select subjects with different hand-type sizes. Experiment1explored the effects of users’ hand-type sizes on the operation on touch-screen mobile phones.We evaluated large, median and small, the three hand-types of users’ operation performance onmedian size touch-screen mobile phones respectively. Experiment2and experiment3investigated the effects of the lengths and widths of mobile phones on the operation ontouch-screen mobile phones respectively. We evaluated median-hand users’ operationperformance on the touch-screen mobile phones respectively with five different lengths and fivedifferent widths. Based on the results of experiment1~3, experiment4finally defined the mostsuitable size range of touch-screen mobile phones for different hand-types of male users by aclose examination on the matching between different hand-type sizes of users and sizes oftouch-screen mobile phones. The above experiments show the following:（1） University students’ hand-type sizes accord with normal distribution in general. Thehand-type sizes could be classified into three types （small-hand, median-hand and large-hand）,based on the cluster analysis. The discriminant functions obtained by conducting a discriminantanalysis could clearly discriminate the type of university students’hand-type size.（2） When the median size mobile phone is used, the operation performance of the threehand-types of users have no significant difference, large-hand users’ hand muscles are morelabor-saving than small-hand users’, and median-hand users hold higher subjective evaluationthan small-hand users and large-hand users.（3） When user’s hand-type is median-hand, the users’ operation performance on fivelengths touch-screen mobile phones have no significant difference, users’ hand muscles on88~97mm long mobile phones are more labor-saving than those on any other longer mobilephones in the condition of small operation range and concentrating below the screen, and usershold higher subjective evaluation on88~97mm long mobile phones than on any other longermobile phones.（4） When user’s hand-type is median-hand, the users’ operation performance on fivewidths touch-screen mobile phones have no significant difference, users’ hand muscles on52~56mm wide mobile phones are more labor-saving than those on any other wider mobilephones, and users hold higher subjective evaluation on52~56mm wide mobile phones than onany other wider mobile phones.（5） For male users of the three hand-types, the touch-screen mobile phones size of about88×52×16mm is the most suitable for the small-hand male users; the size in the range of about88×52×16mm~114×56×11.9mm is the most suitable for median-hand male users; the sizein the range of about114×56×11.9mm~125×63×8.7mm is the most suitable for large-handmale users.