An array substrate for an in-plane switching mode liquid crystal display device includes a substrate, a gate line disposed along a first direction on the substrate, a data line disposed along a second direction and crossing the gate line to define a pixel region, a thin film transistor connected to the gate line and the data line, pixel electrodes disposed in the pixel region and connected to the thin film transistor, common electrodes disposed in the pixel region and alternating with the pixel electrodes, a semiconductor layer underlying the data line and including a portion having a width greater than a width of the data line, and a first blocking pattern comprising an opaque material and disposed under the semiconductor layer.