Optimization and Evaluation of Tablet Keyboard Layout in the Unsupported Case

Tablet PCs are mobile devices that possess a mid-range size and processing speed, situated between that of cell phones and computers. They are highly favored for their easy-to-use and portable features and thus are popularly employed in light office settings due to their availability to a wide user base. Nevertheless, the virtual keyboards on tablets currently available possess layouts and designs that are derived from the physical keyboards of computers or the full 26-key keyboards of smartphones. These keyboards, merely stretched and scaled to fit the tablet screen, lack ergonomic design considerations for specific tablet usage scenarios. As a result, users engaged in text-based office work may experience inconvenience. Therefore, we created a customized, ergonomic, and optimized virtual keyboard for touchscreen tablets by combining different existing keyboard layouts. Our goal was to address the common issues faced by users who hold the tablet with both hands and type with their thumbs. We based the keyboard design on the comfortable typing area of the fingers on a tablet device and developed a test prototype. To minimize interference of existing layout proficiency, we replaced familiar letters of the alphabet with special symbols. An equal number of male and female participants underwent testing comparing the traditional keyboard layout to the new one. Researchers measured the length of the participants’ thumbs, administered subjective scale questionnaires, and separately recorded the time and accuracy of each participant’s use of both keyboards. A regression analysis was conducted to examine the relationship between finger length and typing efficiency among subjects, concerning existing studies. The subjects were divided into three groups based on their finger length - short, medium, and long. Notably, the short-finger group comprised mostly female participants. Results demonstrate that the curved arrangement of the split keyboard significantly improved typing efficiency for users in the short-finger group, while showing no significant change for the other groups. However, there were some negative effects on the correctness rate. It was found that finger length was negatively correlated with the enhancement effect.