초록 ▼

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 f

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.

대표청구항 ▼

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

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; anda 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. 2. The automatic focusing apparatus according to claim 1, wherein the optical imaging unit further comprises a first magnification adjustment lens with a first focal length, and the first magnification adjustment lens is placed in the first imaging optical path for focusing the first sub-beam on the photo-sensor. 3. The automatic focusing apparatus according to claim 2, wherein the optical imaging unit further comprises a second magnification adjustment lens with a second focal length larger than the first focal length, and the second magnification adjustment lens is placed in the second imaging optical path for focusing the second sub-beam on the photo-sensor. 4. The automatic focusing apparatus according to claim 1, wherein the optical imaging unit further comprises a wave plate disposed in an optical path that the beam passes through before the beam is projected to the object or disposed in an optical path that the beam passes through after the beam is projected to the object. 5. The automatic focusing apparatus according to claim 1, wherein the optical imaging unit further comprises an optical path switch movably disposed in the first imaging optical path or the second imaging optical path that the reflecting beam passes through for switching the first sub-beam and the second sub-beam before the reflecting beam enters the photo-sensor. 6. The automatic focusing apparatus according to claim 1, wherein the beam splitter is a polarized beam splitter. 7. The automatic focusing apparatus according to claim 1, wherein the optical imaging unit further comprises at least an optical path differential beam splitter for dividing the first sub-beam and the second sub-beam into multiple beams with different optical distances. 8. An automatic focusing apparatus, comprising: a light source for generating a beam;an optical imaging unit comprising an object lens and a reflective lens, 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 reflective lens switches the reflecting beam to a first imaging optical path or a second imaging optical path;a photo-sensor for sensing an image formed in the first imaging optical path and the second imaging optical path to detect a defocus position of the object; anda focusing regulation unit for focusing 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. 9. The automatic focusing apparatus according to claim 8, wherein the optical imaging unit further comprises a first magnification adjustment lens with a first focal length, and the first magnification adjustment lens is placed in the first imaging optical path for focusing the beam on the photo-sensor. 10. The automatic focusing apparatus according to claim 9, wherein the optical imaging unit further comprises a second magnification adjustment lens with a second focal length larger than the first focal length, and the second magnification adjustment lens is placed in the second imaging optical path for focusing the beam on the photo-sensor. 11. The automatic focusing apparatus according to claim 8, wherein the optical imaging unit further comprises a wave plate disposed in an optical path that the beam passes through before the beam is projected to the object or disposed in an optical path that the beam passes through after the beam is projected to the object. 12. An automatic focusing method, comprising: emitting a beam;focusing the beam by an object lens, so that the beam is projected on an object and reflected via the object to form a reflecting beam;dividing the reflecting beam into a first sub-beam and a second sub-beam, and enabling the first sub-beam and the second sub-beam to be placed in a first imaging optical path and a second imaging optical path with different imaging precisions respectively;sensing an image formed by the first sub-beam or the second sub-beam by a photo-sensor to detect the defocus position of the object;performing a first focusing on a distance between the object and the object lens according to the defocus position of the object, so that the defocus position of the object is placed within an imaging precision of the first optical path; andselecting an imaging precision corresponding to the second imaging optical path and performing a second focusing on the distance between the object and the object lens, so that the defocus position of the object is placed within an imaging precision of the second optical path.