Display device and manufacturing method of the same

A method of manufacturing a display device, comprising:

• forming a switching thin film transistor which has a first semiconductor layer comprising amorphous silicon and a driving thin film transistor which has a control terminal connected with an output terminal of the switching thin film transistor and a second semiconductor layer comprising poly silicon;
• forming a light sensor which comprises a third semiconductor layer simultaneously formed with the first semiconductor layer, a sensor input terminal and a sensor output terminal formed simultaneously with the output terminal of the switching thin film transistor and electrically connected with the third semiconductor layer, and a metal layer simultaneously formed with a control terminal of the switching thin film transistor and preventing external light from being incident to the third semiconductor layer;
• forming an insulating layer on the light sensor;
• forming a first electrode on the insulating layer to be electrically connected with an output terminal of the driving thin film transistor;
• forming an organic layer having a light emitting layer on the first electrode;
• and
• forming a second electrode on the organic layer.