Patent attributes
A lens module for a thin scanning device is to be disposed on an optical path from an original to an image sensor, and includes first to fifth lenses and a stop. The first lens has a focal length and a shape factor with identical signs, and is disposed to form an object distance with the original. The second lens has a focal length with a sign opposite to that of the focal length of the first lens, and a shape factor with a sign opposite to that of the shape factor of the first lens. The stop is disposed between the second and third lenses. The third lens has a positive focal length and a positive shape factor. The fourth lens has a positive focal length and a negative shape factor. The fifth lens has a negative focal length and a positive shape factor.
