Array substrate and method of manufacturing the same, and display device

A method of manufacturing an array substrate, the method comprising a step of forming thin film transistors on a substrate;

• wherein the step of forming the thin film transistors on the substrate comprises:
• forming a first electrically conductive layer on the substrate;
• forming an insulating layer on the first electrically conductive layer;
• forming at least one common holes in the insulating layer to communicate with the first electrically conductive layer;
• forming a first connection portion, which is made of the same material as a second electrically conductive layer, in the at least one of the at least one common holes while forming the second electrically conductive layer on the insulating layer by using a single process, the first connection portion being in electrical contact with the first electrically conductive layer, wherein the first electrically conductive layer includes a common electrode pattern and a gate pattern of the thin film transistors, and the second electrically conductive layer includes a source electrode pattern and a drain electrode pattern of the thin film transistors and leading wires thereof,
• the step of forming the first connection portion, which is made of the same material as the second electrically conductive layer, in at least one of the at least one common holes while forming the second electrically conductive layer on the insulating layer comprises:
• forming the source electrode pattern and the drain electrode pattern of the thin film transistors and the leading wires thereof from metal material while forming the first connection portion in the at least one common holes from the metal material, the first connection portion being in electrical contact with the common electrode pattern.