Patent ID: 7245375

Claim:
A system for measurement on an article, the system comprising: (i) an illuminator for producing light of at least one predetermined wavelength range; (ii) an optical system configured to define at least a measurement channel, the optical system comprising a light directing assembly for directing an illuminating light beam, propagating along an illuminating light path from the illuminator, onto a measurement site of the article, and directing a light beam returned from said measurement site to at least one light detector; (iii) a displacement arrangement associated with at least the light directing assembly of the optical system and configured and operable to rotate said at least light directing assembly of the optical system with respect to a stage supporting the article about a rotational axis substantially normal to the stage, thereby providing rotation of a light incidence plane relative to the article on the stage; and (iv) a control system configured and operable to control operation of said displacement arrangement.