Abstract: A micro-optical grid structure formed on a substrate, a method for producing the grid structure, and a product that includes one or several pattern areas formed by the grid structure. The grid structure is arranged to produce for a viewer a holographic or corresponding visual effect based on the diffraction of light by directing the light diffracted from the grid structure and corresponding to the design wavelength substantially to only a few diffraction orders. Single diffraction order thus corresponds to a certain observing direction of the visual effect observed on said design wavelength. The grid structure is arranged to leave a free range of angles between adjacent observing directions, such that the grid structure being examined from directions corresponding to the range of angles does not produce for the viewer a clearly observable effect based on diffraction, the grid structure is thus substantially transparent.