Patent ID: 7618564

Claim:
A process for the production of light-diffracting microstructures in a layer of photoresist on a substrate, which are produced by superimpositions of a first relief structure with at least one second relief structure serving as a diffraction structure, comprising the steps of a) producing a layer of photoresist with a first relief structure on a flat substrate, which is produced by forming the shape of a relief die disposed in opposite relationship to the substrate, into the free surface of the layer, b) removing the relief die, c) producing an interference pattern on the relief structure, wherein coherent light is divided into a partial beam and a reference beam and the partial beam and the reference beam are caused to interfere including a predetermined intersection angle on the shaped first relief structure, d) orienting the interference pattern which includes fringes of a high level of light intensity separated by fringes of a low level of light intensity in respect of azimuth in relation to the first relief structure by rotation of the substrate about a normal to the plane of the substrate, e) exposing the first relief structure in the photoresist layer by means of the interference pattern during a predetermined time, f) developing the photoresist during a predetermined time, wherein material of the photoresist which was changed during the exposure operation is partially removed and grooves of the diffraction structure are produced in the first relief structure, and g) drying the photoresist.