Touch display substrate and touch detection method thereof

A touch display substrate, comprising:

• a base substrate,
• a photo-sensitive touch element;
• and
• an organic light-emitting diode device;
• wherein the photo-sensitive touch element and the organic light-emitting diode are arranged on the base substrate sequentially;
• wherein the photo-sensitive touch element comprises a touch electrode layer, a photo-sensitive material layer, an insulating layer and an Indium Tin Oxide layer and wherein the touch electrode layer, the photo-sensitive material layer, the insulating layer, and the Indium Tin Oxide layer are arranged sequentially;
• wherein the touch electrode layer is closer to the base substrate than the photo-sensitive material layer,
• wherein the touch electrode layer further comprises a touch sensing area and an orthographic projection of the touch sensing area on the base substrate, wherein the photo-sensitive material layer further comprises a pattern and an orthographic projection of the pattern on the base substrate,
• wherein the Indium Tin Oxide layer further comprises an orthographic projection on the base substrate, and
• wherein the orthographic projection of the touch sensing area completely covers the orthographic projection of the pattern of the photo sensitive material, and the orthographic projection of the touch sensing area is within the orthographic projection of the Indium Tin Oxide layer, and
• the insulating layer is arranged in a crevice of the pattern of the touch electrode layer and in a crevice of the pattern of the photo-sensitive material layer.