Abstract: The substrate 1 for magnetic disks takes the form of a laminate made up of a plurality of individual thin, fiber-reinforced, anisotropic and unidirectional lamellae. These lamellae are arranged staggered on top of each other at few angular spacings, i.e., at great angles of up to 60.degree., and are finally pressed together. The outer layers and lamellae, respectively, may be reinforced by stronger fibers or other material, such as carbon fibers outside and glass fibers inside, to influence the flexural modulus and the shearing modulus independently of each other. This makes for a substrate which consists of anisotropic material, whose characteristics are essentially isotropic, which is lighter than previously used substrates, and which has a higher critical number of revolutions.

Abstract: This invention relates to an interferometric process, and particularly to a process for examining the planarity of surfaces.

Abstract: This invention is directed to an arrangement for compensating and absorbing vibratory oscillations of a driven spring-mass system by means of an auxiliary spring mass system. The drive for a main spring-mass system is designed such that it is guided along the same axis as the main system and oscillates out of phase with the main system.

Abstract: Disclosed is an apparatus for measuring the distance between two or more surfaces by means of a periodically shiftable imaging system and focus detectors.