Abstract: The present invention discloses an optical input device, which comprises a display panel having a displaying area functioning as an interface for detecting a position of an object; a backlight module providing light sources for the display panel; and at least one image sensor arranged behind the backlight module and capturing a positional image, which is formed on the displaying area by an object reflecting the light emitted by the light sources. The present invention not only can decrease the thickness of the optical input device but also can reduce the complexity of the optical system.