Information recording medium, recording/reproducing apparatus, and stamper

Abstract

Data track patterns and servo patterns are formed on an information recording medium by concave/convex patterns divided into ring-shaped regions that are concentric with the data track patterns. In the servo patterns, a unit convex length and a unit concave length along the direction of rotation increase in each ring-shaped region from an inside to an outside of the ring-shaped region in proportion to the distance from the center of the data track patterns and a value produced by dividing an average unit convex (or concave) length inside each ring-shaped region by a distance from the center to the ring-shaped region decreases toward the outer periphery of the medium. The ring-shaped regions include plural first regions between an innermost region and an outermost region. Respective lengths along a radial direction of the first regions increase toward an outer periphery of the medium.