Display device and an inspection method of a display device

A display device, comprising:

• a display panel including a data driving integrated circuit;
• and
• a first substrate attached to a side of the display panel,
• wherein the display panel includes a first panel test pad and a second panel test pad,
• the first substrate includes a 1-1 circuit test lead overlapping and connected to the first panel test pad, a 1-2 circuit test lead overlapping and connected to the second panel test pad, and a first test point directly connected to the 1-1 circuit test lead and the 1-2 circuit test lead.

An inspection method of a display device, comprising:

• providing a display device including a display panel including a first panel test pad, a second panel test pad, a third panel test pad and a fourth panel test pad, a first substrate including a 1-1 circuit test lead, a 1-2 circuit test lead, a 1-3 circuit test lead, a 1-4 circuit test lead, a 2-1 circuit test lead, a 2-2 circuit test lead, a 2-3 circuit teat lead and a 2-4 circuit test lead, wherein the 1-1 circuit test lead to the 1-4 circuit test lead are respectively connected to the first panel test pad to the fourth panel test pad, and a second substrate including a first main test pad, a second main test pad, a third main test pad and a fourth main test pad respectively connected to the 2-1 circuit test lead to the 2-4 circuit test lead, a first test point connected to the first main test pad, a second test point connected to the second main test pad, and a third test point connected to the third main test pad and the fourth main test pad, wherein the 1-1 circuit test lead and the 1-2 circuit test lead are connected to the 2-1 circuit test lead in parallel, the 1-3 circuit test lead is connected to the 2-2 circuit test lead, and the 2-3 circuit test lead and the 2-4 circuit test lead are electrically connected to the 1-4 circuit test lead;
• bringing jigs into contact with the first test point and the second test point to obtain a first measured value;
• bringing the jigs into contact with the second test point and the third test point to obtain a second measured value;
• bringing the jigs into contact with the first test point and the third test point to obtain a third measured value;
• and
• determining a contact resistance between the first panel test pad and the 1-1 circuit test lead, a contact resistance between the second panel test pad and the 1-2 circuit test lead, a contact resistance between the third panel test pad and the 1-3 circuit test lead and a contact resistance between the fourth panel test pad and the 1-4 circuit test lead using the first measured value, the second measure value and the third measured value.