The invention provides an aspherical
focal length-variable photoetching objective lens
system, belonging to the technical field of
optics, and aiming at solving the problem that the existing photoetching objective lens can not
expose mask plate
exposure patterns with different scale sizes by the same photoetching objective lens. The
system provided by the invention from an object plane to an
image plane sequentially comprises: the object plane, a first lens set, a second lens set, a third lens set, a fourth lens set, a fifth lens set and the
image plane; the object plane is the plane where a
mask plate is arranged; the first lens set is used for fixing the distance between the object plane and the first lens set of a
focal length-variable
system; the second lens set is used for changing the
focal length of the photoetching objective lens and the size of the
image plane; the third lens ser is used for compensating the movement of the image plane when a zooming group moves, so that the position of the image plane is invariably kept in the whole process of zooming; the fourth lens set has the
negative power, the fifth lens set has the
positive power, and a back fixed set consists of the fourth lens and the fifth lens, so that the invariable distance between the final lens of the photoetching objective lens which is near to one side of the image plane and the image plane can be guaranteed; and the image plane is the plane where an
etching substrate is arranged.