Patent ID: 7646680
Filing Date: 2010-01-12
Classification: G11B

Abstract:
1. An optical system for efficiently collimating an elliptical light beam, comprising: a light source, for providing an elliptical light beam defining different diverging angles in different directions, wherein any cross-section of the elliptical light beam emitted from the light source defines a long axis and a short axis which are perpendicular to each other; a first lens, for converting the diverging elliptical light beam outputted from the light source into a parallel elliptical light beam; a second lens, functioning as a converging lens in directions corresponding to the long axis, for converging the elliptical light beam, shortening the long axis and keeping the short axis unchanged so as to narrow a difference between the long axis and the short axis; and a third lens, functioning as a diverging lens in the directions corresponding to the long axis, for diverging the elliptical light beams, adjusting the long axis and keeping the short axis unchanged in order to obtain a parallel round light beam;