The invention relates to the technical field of semiconductors, in particular to an automatic focusing
system of a double-
line sensor, which can enable the focusing action to be smooth, improve the focusing efficiency and
shoot a clear and non-
skew picture, and the focusing process is as follows: a
light source irradiates a stripe-shaped pattern, and the stripe-shaped pattern is transmitted to an object after passing through a reflector, a half-reflector and a lens; a graph of an object is divided into two paths after passing through the lens, the half-reflecting mirror, the
imaging lens and the
beam splitter, one path directly enters the image taking device, the other path is divided into two paths again after passing through the light path difference
system, one path passes through the
line sensor A to enable light to be focused on the front side of the
line sensor A, and the other path passes through the line sensor B to enable light to be focused on the rear side of the line sensor B; the line sensor A and the line sensor B send signals to the focusing controller, the focusing controller takes the
signal of the line sensor A and the
signal of the line sensor B which are equal in strength as a focusing
signal, and the focusing controller continuously controls the driver to adjust the distance between the lens and an observed object so as to adjust the
optical path distance and maintain the state of the focusing signal.