Patent ID: 7622206
Filing Date: 2009-11-24
Classification: G11B

Abstract:
1. A silicon substrate for a magnetic recording medium, provided with chamfered portions between main surfaces and an end face of the substrate, wherein the lengths of the chamfered portions between the main surfaces and an outer circumferential side end face are 0.1±0.03 mm, and the angles between the main surfaces and the chamfered portions between the main surfaces and the outer circumferential side end face are 45 degrees ±5 degrees, wherein curved portions with a radius more than 0.01 mm and less than 0.3 mm, when viewed through a cross section of the medium, are interposed between main surfaces and chamfered portions of the substrate, and on both the outer circumferential sides of the substrate, and the silicon substrate has an outer diameter ranging from 0.85 to 2.5 inches.