Determination method for e.g. compact disc, involves determining deformation of tested surface based on reflection point of reflected light from tested surface to planar focal plane

摘要

The light from a light source (14) is reflected to tested surface (12) using substrate (13) formed with contrast rich dark pattern. The deformation or inclination of the tested surface is determined based on reflection point (21) of reflected light from tested surface to planar focal plane (11). There is no deformation when the reflection point corresponds to the desired point (19) of pattern on the plane.