Patent ID: 7567493

Claim:
A multilayer recording medium having a plurality of recording layers, wherein: a thickness of at least one spacer layer between adjacent recording layers is different from a thickness of the other spacer layers such that a beam focusing on one of the recording layers is prevented from focusing on another one of the recording layers corresponding to a mirror layer due to reflection; and when a thickness of a spacer layer between a recording layer “i” and a recording layer “i−1” is D i , the thickness D i satisfies: ∑ i = K + 1 L ⁢ D i ≠ ∑ j = L + 1 Q ⁢ D j , where N is a number of all recording layers included in the multilayer recording medium, K=0, 1, 2, . . . , N−3 is a serial number of each recording layer, L=K+1, K+2, . . . , N−2 is a serial number of a recording layer that is located above a recording layer K and from which an incident beam is reflected, and Q=L+1, L+2, . . . , N−1 is a serial number of a recording layer located above a recording layer L from which the incident beam is reflected.