Patent ID: 7663983

Claim:
An optical information storage medium comprising: a light transmitting layer; a first information storage layer; an intermediate layer that is mainly made of resin; a second information storage layer; and a substrate, the light transmitting layer, the first information storage layer, the intermediate layer, the second information storage layer, and the substrate being layered in this order from a reproduction light incident side, and each of the first information storage layer and the second information storage layer comprising: a light absorbing film that absorbs reproduction light to generate heat; and a reproduction film that is heated by the heat generated by the light absorbing film so as to reproduce a signal shorter in mark length than a resolution limit of an optical system of a reproducing apparatus, wherein the first information storage layer has a transmittance between 25% and 58% with respect to a reproduction light wavelength, wherein the first information storage layer and the second information storage layer are each formed on at least one prepit, and wherein the optical information storage medium is a read-only optical information storage medium.