Patent ID: 8345232
Filing Date: 2013-01-01
Classification: G01N,H01L

Abstract:
1. An inspection system comprising: imaging optics for imaging an object plane into an image plane and comprising an objective lens having positive optical power, a first lens group having negative optical power and a second lens group having positive optical power arranged in this order along a common optical axis; wherein a pupil plane of the imaging optics is located between the first lens group and the second lens group; wherein the imaging optics are configured such that a first length is measured along the optical axis from a lens surface of the objective lens closest to the image plane to a lens surface of the first lens group located closest to the object plane, and at least one of the following relations is fulfilled: i) wherein the first length measured along the optical axis from a lens surface of the objective lens closest to the image plane to a lens surface of the first lens group located closest to the object plane is greater than a second length that is a distance measured along the optical axis from the lens surface of the first lens group located closest to the object plane to a lens surface of the second lens group located closest to the image plane; ii) wherein the first length is greater than a diameter of an object field imaged into the image plane; and iii) wherein the first length is greater than a third length that is a distance measured along the optical axis from the object plane to a lens surface of the objective lens closest to the object plane.