Spatial filter for a reducing pattern-projecting device (pattern projector)

摘要

A spatial filter which is used in a reducing pattern-projecting device has the following features: - a central region which has a reduced transmission of predetermined value and through which the light passes; - a border region which surrounds the central region and is essentially transparent; and - a measure for generating a phase difference of essentially 180 DEG between light beams which pass through the central region and the border region. IMAGE