| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical recording medium that has at least a ROM region and can prevent unauthorized copy for protecting the right of an information author, and to provide an unauthorized copy prevention method for the optical recording medium, and a stamper for forming the substrate of the optical recording medium and a method for manufacturing the stamper. <P>SOLUTION: (1) In the optical recording medium having at least a ROM region, the product W×L of the width W and the length L of a pit having the same n in a pit (n is a specified integer), wherein a signal width existing in the ROM region is nT, is changed at one portion of the ROM region for changing asymmetry and generating a read error in reproduction. (2) A part, wherein the W×L of the ROM region is changed, is a special information section for discriminating media separate from a normal information part. (3) A change in W×L, or a change in asymmetry is continuous or discontinuous in the optical recording medium listed in (1). <P>COPYRIGHT: (C)2005,JPO&NCIPI |
