Patent ID: 7924687
Filing Date: 2011-04-12
Classification: G02B,G11B

Abstract:
1. An optical system for efficiently collimating elliptical light beams, comprising: a light source, adapted 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, functioning as a diverging lens in directions corresponding to the short axis, for diverging the elliptical light beam and enlarging the short axis so as to narrow a difference between the long axis and the short axis and to narrow a difference between a diverging angle corresponding to the short axis and a diverging angle corresponding to the long axis, when the elliptical light beam passes therethrough; a second lens, functioning as a converging lens in the directions corresponding to the short axis, for converging the elliptical light beam and adjusting the short axis in order to obtain a round light beam when the elliptical light beam passes through the second lens; and a third lens for converging the round light beam into a substantially parallel round light beam; wherein the optical centers of the first lens and the second lens commonly define a common optical axis along which the elliptical light beam travels, the light source and the first lens are arranged with no intervening lenses therebetween, and an optical center of the third lens coincides with the common optical axis.