Array substrate, touch screen, touch display device and manufacturing method thereof

The invention provides an array substrate; a driving transistor of a peripheral driving circuit of the array substrate is a bigrid oxide semiconductor transistor; the top grid of the bigrid oxide semiconductor transistor and a touch lead positioned in a display area are formed in the same layer and made of the same material; and furthermore, the material of the top grid is non-transparent metal or alloy thereof having better conductivity, such as molybdenum, aluminium and copper. On the one hand, the bigrid oxide semiconductor transistor can be formed in the peripheral driving circuit in the event that an extra manufacturing process and a photomask are not increased, such that the purpose of controlling the threshold voltage of the oxide semiconductor transistor is realized; on the other hand, a lightproof metal layer is used as the top grid for covering a semiconductor channel region; and thus, photo-generated current can be reduced, such that influence of illumination on the stability of the oxide semiconductor transistor is avoided.