Cylindrical Grating Projection by Single-Shot Normal Exposure of a Radial Phase Mask

Abstract : A periodic grating is defined at the photoresist-coated wall of a circular cylinder with an integer number of particularly long grooves parallel to the generic lines by the holistic exposure of a radial phase mask to a normally incident collimated laser beam. The single- shot projected element corresponds to the inner grating of a high-resolution miniature shaft encoder.