TFT array substrate, preparation method thereof and display panel

A thin film transistor (TFT) array substrate, having a display region, a pad bending region, and a wiring region connected to the display region and the pad bending region, wherein the TFT array substrate comprises:

• a substrate function layer and a plurality of metal layers disposed over the substrate function layer, wherein the substrate function layer comprises a substrate layer, a buffer layer, an active layer, and a first insulation layer, wherein the buffer layer, the active layer, and the first insulation layer are disposed over the substrate layer;
• wherein the metal layers comprise a first metal layer, a second metal layer, and a third metal layer separately disposed within the display region;
• wherein the first metal layer is disposed on the first insulation layer, a second insulation layer is disposed between the first metal layer and the second metal layer, and an inter-layered insulation layer is disposed between the second metal layer and the third metal layer;
• wherein the first metal layer, the second metal layer, and the third metal layer are made of a same metal material, which comprises aluminum or aluminum alloy;
• wherein an organic filling layer is disposed over the substrate layer within the pad bending region, and a plurality of parts of the third metal layer are disposed on the organic filling layer in a spaced manner;
• wherein a part of the first metal layer within the pad bending region is disposed in the organic filling layer within the pad bending region;
• and
• wherein a part of the second metal layer within the wiring region is further disposed on the second insulation layer within the wiring region and is electrically connected to the part of the first metal layer within the pad bending region through a via hole.