Hitachi Maxell, Limited

Other

Hitachi, Ltd.

Reiji Tamura

Yoshihiro Ikari

Motoyasu Terao

Makoto Miyamoto

Yasushi Miyauchi

Hiroshi Shirai

Yumiko Anzai

Junko Ushiyama

Keikichi Andoo

Toshinori Sugiyama

Keikichi Ando

Toshiaki Taii

Tamotsu Fuchioka

Hitoshi Watanabe

Masaaki Futamoto

Akemi Hirotsune

Tetsuya Nishida

Katsusuke Shimazaki

Nobuhiro Tokushuku

Hiroyuki Awano

Yukio Fukui

Masahiko Takahashi

Osamu Ishizaki

Tsuyoshi Maro

Shigenori Okamine

Tamotsu Iida

Takehiko Yorozu

Yuji Yamazaki

Hideki Nagano

Makoto Iimura

Norio Ota

Akira Kashiwakura

Kazuyoshi Adachi

Kazuyo Umezawa

An optical disk includes a first area on which user information is recorded, and a second area in which a plurality of marks radially extending are arranged in a track direction in the optical disk. Information about the reflectance of the optical disk is recorded in the second area. It is intended to optimize the amplification factor of the reproduced signal on the basis of the information about the reflectance of the optical disk in the second area. Control data and user data can be reproduced quickly and highly reliably without depending on the relationship between the reflectances of a recording area and a non-recorded area of the optical disk.

Optical recording and reproducing apparatus capable of identifying the type of optical disc based on reflectance, and reproducing method for optical disc

Optical disk with a plurality of radially extending marks for recording reflectance data of the optical disk

An optical disk includes a recording region formed on a substrate for recording user data, and a management region formed on the substrate which includes an identification information region for recording disk-specific identification information such as address information (ID), a SYNC code, or an error detection code (EDC). The identification information region in this optical disk has a flat portion (a mirror region) formed by means of sectioning part of a groove or a land in a given step. The disk-specific identification information is recorded on the identification information region inclusive of this mirror region as irreversible record marks. Moreover, a signal of the disk-specific identification information is detected by a laser beam which is servoed on the recording track of this optical disk. Then, a change in the detected signal level of the disk-specific identification information is detected based on a predetermined threshold level.

Optical disk, method of playing optical disk, and optical disk drive

A write-once optical information recording medium is provided that is capable of realizing a high transfer rate and a method of recording and reproducing information on and from the optical information recording medium. The optical information recording medium is constructed by stacking a reflective layer, a first dielectric layer, a recording layer, a write-protect layer, a second dielectric layerand a transparent cover layeron a polycarbonate substrate. The recording layeris made of a phase-change material, and the cover layeris made of UV curing resin. The recording layeris irradiated with a laser beam with a wavelength of 500 nm or less to change from a crystalline phase to an amorphous phase. The write-protect layerprevents the recording layerfrom changing back to the crystalline phase from the amorphous phase, formed by the phase change.

Optical information recording medium and method of recording and reproducing information on and from optical information recording medium

In an optical disk for high density recording, for preventing the deformation of recording tracks caused by stress which may develop between the substrate and the recording stacked film formed thereon, a stress-compensation layer having a metal element such as Ti or Cr as a main component is provided. The stress-compensation layer undergoes contraction (tensile stress) to compensate for compression stress which develops in the stacked film during cooling after the thermal expansion of the substrate surface that occurs at the end of film formation. The stress-compensation layer has a pillar-like structure which, starting from the lower face, reaches the upper face of the film.

Information recording medium and method for manufacturing information recording medium

A magneto-optical recording head comprises a magnetic coil formed on a lower surface of a transparent substrate opposed to a magneto-optical disk. A heat sink layer is provided at the outside of the magnetic coil on the lower surface. An objective lens is supported on an upper surface of the transparent substrate. The heat, which is generated by the magnetic coil, is released via the heat sink layer to the space between the magneto-optical disk and the substrate. The release of the heat is facilitated by the air stream which is generated by the rotation of the magneto-optical disk. The heat can be effectively released from the magnetic coil without inhibiting optical characteristics of the objective lens.

Magneto-optical head having heat sink layer

A high-density information recording medium free from lowering the reflectance by over-write of a large number of times and exfoliation defect in a structure for suppressing cross-erase. This medium includes, over a substrate having a groove shape, a recording layer, and three-layered thin films of a first interference layer, a second interference layer and an interface layer having mutually different compositions and disposed on a laser beam incidence side of the recording layer in order named from the laser beam incidence side. The first interference layer has a smaller refractive index and a larger thermal conductivity than the second interference layer, the interface layer is interposed between the second interference layer and the recording layer, and a distance between the first interference layer and the recording layer is greater than at least a groove depth.

Information recording medium

An information recording medium having recording, reproducing, and rewriting characteristics better than those of prior art media. The media has a recording layer made of a material represented by the following formula: Ge Sb Te M , wherein 0.13&lE;x&lE;0.22, 0.20&lE;y&lE;0.32, 0.53&lE;z&lE;0.60, 0&lE;w&lE;0.06, x&plus;y&plus;z&equals;1, and M is any one of Na, Mg, Al, P, S, Cl, L, Ca, Sc, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Ru, Rh, Cd, In, Sn, I, Cs, Ba, La, Hf, Ta, Re, Os, Ir, Hg, Tl, Pb, Th, U, Ag, Cr, W, Mo, Pt, Co, Ni, Pd, Si, Au, Cu, V, Mn, Fe, Ti and Bi.

Disclosed is a phase-change optical recording medium which has a reflectance and a signal modulation conformed to the CD standard, and which is usable for recording at the same linear velocity as the reproducing velocity specified in the CD standard. The phase-change optical recording medium comprises a metallic layer, a first protective layer, a recording layer, a second protective layer, and a reflecting layer on a substrate, in which recording is performed through change from a crystalline state to an amorphous state in the recording layer. The recording layer comprises a recording material of a Ge--Te--Sb--Se system, and the recording layer has an average composition in a direction of thickness which satisfies the following relations as represented by atomic %:

Optical recording medium

By using an information recording medium comprising at least a substrate and an information recording film which is mounted on the above substrate and changes the physical property under irradiation of a recording energy beam, wherein the surface of the information recording area of the above substrate is uneven, both surfaces of the above recording film are also uneven, and an inorganic protective layer is provided in contact with the surface of the above recording film opposite to the above substrate, fine recording points can be formed stably without complicated control of the recording power and recording waveform so that an optical disk unit can record data simply in high density.

Information recording media, manufacturing method for the same, and

Growing community of inventors

Moriya, Japan

Reiji Tamura