Patent ID: 7532414

Claim:
An optical system for use in measurement/inspection of an article, the optical system comprising an illuminator arrangement, and a light directing unit configured for focusing incident light beam from said illuminator arrangement onto an article under measurement/inspection at substantially normal incidence and for collecting light from the article, said light directing unit comprising an objective arrangement comprising a first reflective element having a concave reflective surface and defining an optical axis of the incident light propagation towards the article, and a second substantially flat and at least partially reflective element spaced-apart from said first reflective element along said optical axis, the second element being configured to allow light passage therethrough and being oriented with respect to the optical axis and the first element such that at a predetermined angle of incidence of the incident light beam from said illuminator arrangement onto the second element, so that said incident light beam is reflected onto the reflective surface of the first element and further reflected therefrom to pass through the second element and focus on the article.