Confocal measurement and diagnostic system

Abstract

A confocal optical system is disclosed that utilizes fiber optic components in its construction. The system includes a light source, two detection units, an aperture and an optical element all optically coupled to a fiber optic coupler via optical fibers. In addition, a novel automatic focusing device is disclosed which utilizes chromatic aberration to maintain a target object in optimal focus. The device includes two light sources having different wavelengths of light, an optical element, an aperture, two detection units and a beam splitter. One light source is used to achieve initial focus and to illuminate the target object. The second light source is used to maintain the target object in optical focus. Light reflected off the target object is measured by one of the detection units. The magnitude of the light of the second wavelength measured by the detection unit is utilized to maintain focus. A second detection units is utilized to measure the intensities of the two light sources to yield normalized results. Further, a method of diagnosing an optical system is also disclosed. The method includes comparing a current set of readings of light against a set of reference readings taken at an earlier point in time. If the difference exceeds a predetermined threshold, a problem is indicated.