Patent ID: 7858268

Claim:
A method for generating a periodic circular structure in a basic support material comprising the steps of: a) generating a plurality of diffraction masks such that each mask includes at least one transmission diffraction grating having at least one pattern selected from the group consisting of a periodic concentric circular pattern, a spiral-like periodic pattern and a periodic radial spoke pattern; b) positioning the plurality of the diffraction masks simultaneously or successively at a certain distance from the basic support material to be patterned, the distance being mask dependent; c) exposing the basic support material by directing light beams through each of the plurality of the diffraction masks; and d) interfering the different light beams diffracted by the grating on each mask in order to generate coincident light intensity patterns on the surface of the basic support material; wherein the step of exposing further comprises the steps of: generating said exposure using a first transmission diffraction mask having a combined circular and spiral interference mask pattern so as to generate a first spiral track pattern on the basic support material; and after said step of generating said exposure further generating said exposure using a second transmission diffraction mask having a combined circular and spiral extending interference mask pattern wherein said spiral component is oriented in an opposite direction to the first transmission diffraction mask, the second transmission effecting a partitioning of said generated first spiral track pattern by intersecting said first and said second spiral track pattern.