Touch display panel and display device

A display device, comprising a touch display panel, wherein the touch display panel comprises a color filter substrate, an array substrate, a back light source arranged below the array substrate and a liquid crystal layer arranged between the color filter substrate and the array substrate, the color filter substrate comprises a black matrix, and the touch display panel further comprises an optical sensor provided with a light detection surface facing the liquid crystal layer;

• and
• wherein the optical sensor is configured to detect light emitted by the back light source, propagating through the liquid crystal layer, and then arriving at the light detection surface of the optical sensor, to acquire detection data for determining a position of a touch operation performed on the touch display panel;
• an orthographic projection of the light detection surface of the optical sensor onto the array substrate is located within an orthographic projection of the black matrix onto the array substrate.