Investigating visual and interaction designs of a semi-transparent keyboard for a touch screen tablet computer

Abstract

As tablet computers are hosting more productivity applications, efficient text entry is becoming more important. A soft keyboard, which is the primary text entry interface for tablets, however, often competes with applications for the limited screen space. A promising solution to this problem may be a semi-transparent soft keyboard (STK), which can share the screen with an application. This dissertation addressed two problems when using an STK.

The first problem is a visual conflict between the keyboard and a background application. Series of explorative design studies revealed that expert UI designers favored borderless keyboard designs, which shows the position of keys only with labels. Compared to an opaque keyboard, the STK designs could reach about 92% speed in reading performance, and equivalent performance in typing speed and errors. Also, the text caret could intrude the STK down to the number row without significant performance reduction.

The second problem is an interaction conflict. When using an STK, the keyboard covers part of an application and blocks the access to the underlying application UI. This dissertation explored possible interaction methods for this situations and implemented two promising methods. One method is using a quasimode. While pressing a mode change button, a user can temporarily hide the keyboard, do a job with the background application, and quickly returns to typing task by releasing the button. Another method is using touchpad-like gestures on an STK. These gestures allow users to access the background contents through a mouse cursor. Additionally, the fingers are staying in home position, and hand movement could be minimized.

Regarding the findings above, I implemented an example STK that works on real applications, and the STK was effectively blended with various application contexts. Also, the STK could handle almost every document editing tasks with the proposed interactions and provided a remedy for some chronic problem of touchscreen interactions.