Abstract: A TFT LCD device is comprised of four TFT's with two separate sources, two separate drains and one common source-drain which is shared by the four respective TFT's, either acting as source or drain. The gate structure employs only one gate line with a bypass line. By sharing of the Si island and the centralization of the gate electrode of four TFT's, the pixel open ratio increases quite substantially. The devices are connected to the two adjacent pixels separated by the gate line via the two drain electrodes. Each pixel electrode is connected to the two adjacent devices via the two drain electrodes. Each pixel electrode can receive the data signals which are controlled by the two adjacent devices, to form a redundant structure for improving the yield of the TFT LCD. The common source-drain is situated along the gate bus line, and doesn't occupy too much of the pixel area, to thereby provide a large open ratio.