An optical apparatus for a line scanner system comprises a main lens group, an
aspherical field flattener lens and a line sensor arranged sequentially along the
same optical axis. The main lens group consists of four rotationally symmetrical
lenses for refracting and converging light beams into focus. The field flattener
lens is rotationally symmetrical in its optical profile and shapes as a strip oriented
along the direction of the line image. The field flattener lens is arranged between
the main lens group and the line sensor and closer to the line sensor for refracting
the light beam to the line sensor in a relatively wide field angle, and as a result,
various aberrations have been corrected while the optical total track also has
been reduced. And an image plane is provided in the line sensor for the linear
light beam, in which the instantaneous field of view is a line.
