LITHOGRAPHY SYSTEM WITH BEAM GUIDANCE AND METHOD FOR PRODUCING DIGITAL HOLOGRAMS IN A STORAGE MEDIUM

摘要

The invention relates to a lithography system for producing digital holograms in a storage medium comprising a light source (8) for generating a writing beam (10), driving means (12, 14) for moving the writing beam (10) in two dimensions with regard to the storage medium (4), and a first lens (16) for focussing the writing beam (10) onto the storage medium (4) to be written. The aim of the invention is to be able to use optical lithography to write computer generated holograms as quickly as possible and with a low degree of complexity while, at the same time, precisely controlling the positioning of the writing beam. To this end: a two-dimensional beam guiding mask (18) is provided; means (20) for generating a scanning beam (22) are provided; a second lens (24) is provided for focussing the scanning beam (22, 22') onto the beam guiding mask (18); the drive means (12, 14) displace the scanning beam (22) in two-dimensions with regard to the surface of the beam guiding mask (18), whereby the movement of the scanning beam (22, 22') is linked to the movement of the writing beam (10); a detector (30', 30'') is provided for picking up the scanning beam whose intensity is varied by the optical properties of the track (44); means (32, 34) are provided for tracking the writing beam (10) and the scanning beam (22), and; means (26) are provided for generating a position control signal. The invention also relates to a method for producing digital holograms in a storage medium.