Light projecting method, surface inspection method, and apparatus used to implement these methods

摘要

The present invention provides a light illuminating method, a surface examining method using the light illuminating method, and apparatuses for performing these methods. In the surface illuminating apparatus for illuminating an object with a light beam from a light source through a lens member for illumination, the lens member for illumination has a characteristics with respect to a longitudinal aberration caused by a spherical aberration in the light source side of the lens for illumination, that an amount of shift from a paraxial image surface to image formation points gradually increase or decrease, with an increase in height of light incidence into the lens; and the light source is set at a position in an outside of a group of the image formation points.