Array substrate, method for manufacturing the same and display device

A method for manufacturing an array substrate, comprising:

• providing a base substrate;
• forming a conductive material thin film on the base substrate;
• forming a first photoresist layer on a side of the conductive material thin film distal to the base substrate, wherein the first photoresist layer comprises a first covering portion corresponding to a gate electrode, a second covering portion corresponding to a signal line, and third covering portions which are respectively on two sides of the second covering portion and connected with the second covering portion, and a thickness of each of the third covering portions is smaller than a thickness of the second covering portion;
• etching the conductive material thin film by using the first photoresist layer as a mask to obtain a first etched pattern;
• removing the third covering portions of the first photoresist layer to obtain a second photoresist layer;
• and
• etching the first etched pattern by using the second photoresist layer as a mask to obtain the gate electrode and the signal line.