Automatic focusing apparatus and method

摘要

An automatic focusing apparatus and a method thereof are provided. The apparatus includes a light source, an optical imaging unit, a photo-sensor and a focusing regulation unit. The optical imaging unit includes an object lens and a beam splitter. The beam splitter divides a reflecting beam into a first sub-beam and a second sub-beam. The optical imaging unit has a first imaging optical path and a second imaging optical path with different imaging precisions corresponding to the first sub-beam and the second sub-beam, respectively. The photo-sensor detects a defocus position of the object. The focusing regulation unit adjusts the distance between the object and the object lens and selects an imaging precision, so that the defocus position of the object is placed within the imaging precision of the first optical path and the imaging precision of the second optical path in sequence.

主权项

1. An automatic focusing apparatus, comprising:
a light source for generating a beam; an optical imaging unit comprising an object lens and a beam splitter, wherein the object lens focuses the beam, so that the beam is projected on an object and reflected via the object to form a reflecting beam, the reflecting beam is divided into a first sub-beam and a second sub-beam by the beam splitter, and the optical imaging unit has a first imaging optical path and a second imaging optical path with different imaging precisions corresponding to the first sub-beam and the second sub-beam, respectively; a photo-sensor for sensing an image formed by the first sub-beam or the second sub-beam to detect a defocus position of the object; and a focusing regulation unit for performing focusing on a distance between the object and the object lens and selecting an imaging precision according to the defocus position of the object, so that the defocus position of the object is placed within the imaging precision of the first optical path and the imaging precision of the second optical path in sequence.