A pixel array substrate includes a substrate, pixels, and connection wires. The substrate has a transparent window, a wire region, and an active region. The connection wires are disposed in the wire region. Each connection wire is electrically connected to first signal lines of the pixels respectively located on two opposite sides of the transparent window. The connection wires include first and second wire groups. The first wire group includes first connection wires. Each first connection wire has a first segment and a second segment. A first insulation layer is disposed between the first and second segments that are electrically connected to each other. The second wire group includes second connection wires. The first segments of the first connection wires and the second connection wires are overlapped, and the first insulation layer is disposed between the first segments of the first connection wires and the second connection wires.