Patent ID: 8014260
Filing Date: 2011-09-06
Classification: G03H,G11B

Abstract:
1. An optical information recording medium for being irradiated with an access control laser beam in addition to a recording laser beam having an information beam which bears information by spatially modulating a laser beam and a recording reference beam, comprising: a substrate having pregrooves for use in access control, defined in a principal surface thereof in an effective access area which can be accessed by said access control laser beam; a reflecting layer disposed on the principal surface of said substrate, for reflecting said access control laser beam; a selective reflecting layer disposed on said reflecting layer, for passing said access control laser beam therethrough and reflecting said recording laser beam; and a recording layer disposed on said selective reflecting layer, for recording information therein with said recording laser beam; said substrate having a dummy region in an area of said principal surface adjacent to said effective access area, said dummy region having dummy pregrooves similar to said pregrooves, wherein said dummy region is disposed between said effective access area and an outer circumferential end of said substrate and adjacent to an outermost edge of said effective access area, wherein said dummy region which is disposed between the outermost edge of said effective access area and the outer circumferential end of said substrate has an outer end in a position which is spaced 1 mm or more from the outer circumferential end of said substrate toward the center of said substrate, and wherein said dummy region has an inner end in a position which is spaced 10 mm or less from the outer circumferential end of said substrate toward the center of said substrate.