A scanning module for scanning a document is provided. The scanning module comprises: a chassis; a light source on the chassis for emitting a light ray onto the document; a plurality of reflectors inside the chassis; a lens inside the chassis; an image sensing device inside the chassis, an image of the document being reflected by the plurality of reflectors and formed on the image sensing device, the image sensing device including a plurality of sensing cells; and a plurality of microlenses on the plurality of sensing cells, each of the plurality of microlenses having a top surface and a bottom surface, the top surface having a plurality of notches as an input window for changing an incident angle of the light ray, the bottom surface having a plurality of round curves as an output window for further focusing the light ray.