Design and Evaluation of Semi-Transparent Keyboards on a Touchscreen Tablet

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. A few commercial STK products are already available, but research questions about the STK design have not been explored in depth yet. Therefore, we conducted three experiments to answer 1) the effect of the transparency level on usability, 2) exploration of diverse design options for an STK, and 3) the effect of an STK on the different text caret positions. The results imply that STKs with 50% opacity showed a balanced performance; well-designed STKs were acceptable in both content reading and typing situations; which could reach 90-100% of an opaque keyboard in terms of overall performance; and the text caret could intrude the STK down to the number row.