The present disclosure provides a backlight module, a method for operating the same and a display device including the backlight module. The backlight module comprises a light guide plate, a collimated light source and a shading plate between the light guide plate and the collimated light source. The light guide plate comprises a transparent main body and a plurality of diffusion dots formed on the transparent main body. The shading plate comprises a plurality of shading regions corresponding to the plurality of diffusion dots of the light guide plate. The collimated light source generates collimated light vertically irradiating on the shading plate.