A display includes a backlight source, display panel, first light source, and controller. The display panel includes a sensor array for sensing first reflection light generated from an object reflecting first detection light. The first detection light is generated by the backlight source for locating a coordinate of a projection point of the object on the display panel. The first light source is disposed in a first side of the display panel, for repeatedly transmitting second detection light of different transmitting angles to the object at different time to generate a second reflection light. The second reflection light is sensed by the sensor array. The controller is for performing a corresponding operation according to a transmitting angle of the first light source and the coordinate of the projection point when brightness value of the reflective light is substantially greater than a predict value.