Abstract: The invention relates generally to optical data storage media, and more specifically, to holographic storage media. In one embodiment, an optical storage medium composition includes a polymer matrix. Disposed within the polymer matrix is a reactant capable of undergoing a modification that alters the refractive index of the composition upon receiving an energy transfer from an excited sensitizer. A non-linear sensitizer is also disposed within the polymer matrix, and the sensitizer includes a metal-substituted subphthalocyanine (M-sub-PC) reverse saturable absorber configured to become excited upon exposure to light beyond an intensity threshold at approximately 405 nm and configured to transfer energy to the reactant.

Abstract: The invention provides a master disc comprising a stack of a substrate, a phase transition material layer, a heat absorption layer provided between the substrate and the phase transition layer, and an anisotropic heat sink layer provided between the substrate and the absorption layer. Further, a method of manufacturing a master disc is provided. A stack having an upper side and a lower side is provided, wherein the stack comprises a substrate provided at the lower side of the stack, a phase transition material layer, a heat absorption layer provided between the substrate and the phase transition layer, and an anisotropic heat sink layer provided between the substrate and the absorption layer. The upper side of the stack is exposed to a laser beam and developed.

Abstract: A pressure-sensitive adhesive sheet 1 for an optical data recording medium D1 from which a signal with a mark length shorter than the resolution limit of an optical system of a reproducing device is capable of being reproduced by reproduction light emitted during reproducing, the pressure-sensitive adhesive sheet 1 having an adhesive transparent resin layer 11 to be disposed on an data recording layer 3 of the optical data recording medium D1, the transparent resin layer 11 having a (meth)acrylate copolymer containing no acidic group as a main component, the transparent resin layer 11 having a storage elastic modulus at 23° C. of 1.5×105 Pa or less and a gel fraction of 68 wt % or more.

Abstract: An optical disk having a recording layer on a substrate, a bonding layer which is made of an ultraviolet cured resin bonding the recording layer, a transparent layer which is bonded to the bonding layer, and an overcoating layer which is formed on the transparent sheet and is made of the ultraviolet cured resin further has a mixed layer which is formed by mixing the ultraviolet cured resins of the bonding layer and the overcoating layer. Consequently, the bonding layer, the overcoating layer, and the mixed layer are integrally cured, so that the substrate is entirely covered with the ultraviolet cured resin having transparency, which allows a light transmitting layer A to be protected with sufficient strength.

Abstract: An apparatus for storing digital media utilizes an electrically conductive element, which is for reading stored digital media, and multiple electrically conductive resonant circuits as an antenna for radio frequency communications. Each of the resonant circuits is electrically isolated from the other resonant circuits and the electrically conductive element is electrically isolated from each of the resonant circuits. As a result, the apparatus for storing digital media has a relatively wide operating frequency range and a relatively long communications range, which allows worldwide usage in various applications. For example, an optically readable compact disk (CD) utilizes a metal layer configured as a reflective surface for reading stored digital media in the CD, an electrically conductive component that is not in contact with a radio frequency identification (RFID) integrated circuit (IC), and an electrically conductive component that is in contact with the RFID IC, as an antenna for the RFID IC.

Abstract: According to one embodiment, a write-once type information storage medium comprises a recording layer which is formed by mixing a plurality of organic dye based recording materials whose molecular weights are different from each other, and wherein a mixture ratio of organic dye based recording materials whose molecular weight is small is larger than a mixture ratio of organic dye based recording materials whose molecular weight is large.

Abstract: The present invention has an object of providing an optical information recording medium including three or more information layers, which allows information to be reproduced from all the information layers at high quality, and a method for reproducing information from such an information recording medium. The reflectance of a third information layer 43 is made higher than that of each of a second information layer 42 and a first information layer 41. Thus, the upper limit reproduction power of laser light 31 directed to the third information layer 43 can be made lower than that of the laser light 31 directed to each of the second information layer 42 and the first information layer 41. For reproduction, the reproduction power of each information layer is equal to or lower than the upper limit reproduction power, and a product of the reflectance and the reproduction power is substantially the same among the information layers. Thus, the information reproduction can be conducted at high quality.

Abstract: An information recording medium includes a plurality of layers for recording or reproduction of information by irradiation, wherein each of the layers includes an emboss portion and wobble portion including wobbles of a first frequency and a second frequency that is different from the first frequency. The first frequency is constant in each of the plurality of layers, and a different signal is obtained from the wobbles of the first and second frequencies in each of the plurality of layers.