Array substrate and fabrication method, display panel, and display device

A method of fabricating the array substrate, comprising:

• providing a substrate;
• depositing a graphic pattern of a first functional layer on the substrate;
• depositing a first insulating layer on the first functional layer;
• depositing a graphic pattern of a second functional layer on the first insulating layer;
• depositing a second insulating layer on the second functional layer;
• etching the first and second insulating layers to form a plurality of first-type through-holes that penetrate the first and second insulating layers;
• depositing a graphic pattern of a third functional layer on the second insulating layer, and electrically connecting at least a portion of the third functional layer to at least a portion of the first functional layer by the first-type through-holes;
• depositing a third insulating layer on the third functional layer;
• etching the third insulating layer to form a plurality of second-type through-holes that penetrate the third insulating layer;
• and
• depositing a graphic pattern of a fourth functional layer on the third insulating layer, and electrically connecting at least a portion of the third functional layer to at least a portion of the fourth functional layer by the second-type through-holes.

A display panel, comprising an array substrate and a light emitting functional layer located on the array substrate, wherein the array substrate comprising:

• a substrate;
• a first functional layer configured on one side of the substrate;
• a first insulating layer configured on the first functional layer facing away from the substrate;
• a second functional layer configured on the first insulating layer facing away from the substrate;
• a second insulating layer configured on the second functional layer facing away from the substrate;
• a third functional layer configured on the second insulating layer facing away from the substrate;
• a third insulating layer configured on the third functional layer facing away from the substrate;
• a fourth functional layer configured on the third insulating layer facing away from the substrate;
• and
• a plurality of through-holes configured to electrically connect different functional layers, wherein the depth of any through-holes does not exceed the thickness of two adjacent insulating layers.

A display device, comprising a display panel which includes an array substrate and a light emitting functional layer located on the array substrate, wherein the array substrate comprising:

• a substrate;
• a first functional layer configured on one side of the substrate;
• a first insulating layer configured on the first functional layer facing away from the substrate;
• a second functional layer configured on the first insulating layer facing away from the substrate;
• a second insulating layer configured on the second functional layer facing away from the substrate;
• a third functional layer configured on the second insulating layer facing away from the substrate;
• a third insulating layer configured on the third functional layer facing away from the substrate;
• a fourth functional layer configured on the third insulating layer facing away from the substrate;
• and
• a plurality of through-holes configured to electrically connect different functional layers, wherein the depth of any through-holes does not exceed the thickness of two adjacent insulating layers.