SMALL-SIZED HIGH-DENSITY OPTICAL INFORMATION STORAGE MEDIUM, ESPECIALLY RELATED TO REALIZING A HIGH-DENSITY RECORDING CAPACITY AS WELL AS PORTABLE PROPERTIES BY MINIATURIZING A DISK

摘要

PURPOSE: A small-sized high-density optical information storage medium is provided to newly define a clamping area and an information area while reducing a disk thickness, in order to obtain a high-density recording capacity as maintaining recording and/or reproducing properties of a disk. CONSTITUTION: An information area(IA) consists of a data area(40) where user data is recorded, a lead-in area(30) adjacent to an inner side of the data area(40), and a lead-out area(50) adjacent to an outer side of the data area(40). An area(25) is formed with a stack ring for preventing an information surface from being damaged owing to a disk information surface contact by other disk when a fabricated disk is loaded. The entire diameter of an optical information storage medium is less than 65mm, while the medium is 0.35 to 0.9mm in thickness. A start position of a clamping area(20) is at least more than 3mm in diameter.