Patent ID: 6507017
Filing Date: 2003-01-14
Classification: G01Q,Y10S

Abstract:
An apparatus for optical inspection of an article utilizing near-field illumination, the apparatus comprising a light source unit generating incident light, a detector unit for sensing light signals and providing data representative thereof, a light detecting system, and a control means comprising sensing means and capable of adjusting the position of the light directing system relative to the surface of the article, the apparatus being characterized in that:the light directing system comprises a fiber bundle which is composed of a group of illuminating fibers directing the generated light from the light source onto a surface area of the article, so as to illuminate said surface area with the group of a plurality of light components, and of a group of light collecting fibers collecting light returned from the illuminated surface area and directing the collected light towards the detector unit; said sensing means comprises at least three sensing tips which are attached to an end of the fiber bundle which is to be located close to the surface of the article, when in an operational position of the apparatus, and are arranged so as to define a single common plane, a tunneling current through the tips being thereby indicative of a distance between the surface of the article and said plane defined by said at least three tips.