A transistor array substrate includes a substrate (having a first trench), a gate electrode (in the first trench), an insulating film, a gate line, a data line, a source electrode, and a drain electrode. The insulating film includes second, third, fourth, fifth, and sixth trenches. The gate line is in the second trench and is not parallel to the data line. The data line includes a first section and a second section that are separated by the gate line and respectively in the third and fourth trenches. The source electrode and the drain electrode are respectively in the fifth and sixth trenches. The source electrode is electrically connected to the data line. The gate electrode is electrically connected to the gate line.