Abstract: Controlled laser texturing of a magnetic recording disk is accomplished by use of a textured test band on the disk and an analyzing laser system to provide feedback to the texturing laser. The analyzing laser system determines, from diffracted laser light, the average height of the laser-induced bumps formed in the test band by the texturing laser. The analyzing laser beam is directed to the substrate surface and overlaps a group of individual bumps formed in a repetitive pattern. A scanning linear photodector array receives light diffracted from the surface. The digitized output of the array is the angular distribution of diffracted light intensities and is used to compute the average height of the bumps in the test band. The disk is then translated radially so that the texturing laser is aligned with the region of the disk where the textured landing zone is to be placed.

Abstract: An analyzing laser system determines a physical characteristic of a repetitive texture pattern formed on a substrate surface. In one embodiment the system uses diffracted laser light to compute the average height of texturing bumps on a substrate surface. A laser beam is directed to the substrate surface and overlaps a group of individual marks or bumps formed in a repetitive pattern. A scanning linear photodector array receives light diffracted from the surface. The digitized output of the array is the angular distribution of diffracted light intensities. In the preferred embodiment for determining the average height of laser-induced bumps formed on a specular magnetic recording disk substrate, the angular positions of the first and second diffraction peaks or rings are determined and the intensities are integrated around those diffraction peaks or rings.