REFRACTION LENS, REFRACTION LENS MANUFACTURING METHOD AND ERROR DETECTION SYSTEM USING THE LENS

摘要

PURPOSE: A refractor, a method for fabricating a refractor, and an error detection system using the same are provided to detect a focus error and a spherical aberration error and reduce the power consumption by using an optic complex function lens and an error detector. CONSTITUTION: A refractor includes an internal lens part and a doughnut-shaped external lens part. The internal lens part(32) is formed on an upper surface of a single glass substrate in order to provide a reference focus. The doughnut-shaped external lens part(33) is formed around the internal lens part in order to surround the internal lens part. The focal length between the doughnut-shaped external lens part and the internal lens part is changed by generation of spherical aberration. The internal lens part is formed with an elliptical lens in order to detect a focus error.