Wiring substrate, light-emitting substrate, and display apparatus

A wiring substrate comprising a plurality of functional units arranged in an array;

• wherein each of the functional units comprises:
• a plurality of first pad groups arranged at intervals along a first direction, wherein each of the first pad groups comprises a first sub-pad and a second sub-pad spaced along a second direction;
• and
• a second pad group located at a side of the plurality of the first pad groups along the second direction, wherein the second pad group comprises a plurality of channel pads and at least two functional pads, and a—number—of pads in the second pad group is even and the pads in the second pad group are arranged at intervals in a 2*N array;
• wherein, the plurality of channel pads are arranged at intervals along a same direction in a first line and are respectively connected one-to-one with a plurality of first pad groups of which a—number—is same as a—number—of the plurality of the channel pads;
• a functional pad in the at least two functional pads is located in the first line and is adjacent to one of the plurality of channel pads;
• and rest functional pads in the at least two functional pads are arranged at intervals along a same direction in a second line.