Patent ID: 6721265
Filing Date: 2004-04-13
Classification: G11B

Abstract:
An optical information recording medium for recording optically readable signals thereon by using a laser beam, comprising:a light transmitting substrate, a tracking groove formed on a surface of the light transmitting substrate, the surface having an inner peripheral region and an outer peripheral region; a recording layer formed on the surface having the tracking groove, and a reflective layer, formed on the recording layer, for reflecting the laser beam, wherein a width W1 of the groove at the inner peripheral region is greater than a width W2 at the outer peripheral region, and wherein an index L is defined as 1âˆ’B/A and is within the range from about 0.2 to about 0.5 throughout the inner and the outer peripheral regions, A being a depth of the tracking groove and B being a depth of the recording layer at a same position from a plane view point of the recording layer.