Sony Corporation

Samsung Electronics Co., Ltd.

Panasonic Corporation

Tdk Corporation

Hitachi Consumer Electronics Co., Ltd.

Sony Corporationn

Yoshihiro Akimoto

Minoru Kikuchi

Fuminori Takase

Nobuhiro Saito

Sung-hee Hwang

Harukazu Miyamoto

Motoshi Ito

Hiroyasu Inoue

Yasumori Hino

Shoei Kobayashi

Koichiro Nishimura

In-oh Hwang

Kimihiro Saito

Toshiyuki Kashiwagi

Akiya Saito

Masaki Kagawa

Noriko Kikuchi

An optical recording medium and a manufacturing method for forming the optical recording medium is provided. The optical recording medium includes a bar code-shaped reflection pattern that includes high reflection rate regions and low reflection rate regions and information is recorded with the bar code-shaped reflection pattern. The low reflection rate region is formed with pit strings. The high reflection rate region and the low reflection rate region are formed to satisfy: S+M/2&#x2266;0.6H, where a signal level of a reproduction signal obtained from a reflection light in the high reflection rate region is denoted as 'H', a signal level of a reproduction signal obtained from a reflection light in the low reflection rate region is denoted as 'S', and a degree of modulation of the reproduction signal obtained from the reflection light in the low reflection rate region is denoted as &#x201c;M&#x201d;.

Optical recording medium, manufacturing method for optical recording medium

The present invention is to realize a proper inner zone layout in a quadruple-layer disk. A test area is provided in the inner zone (inner circumference side area) in each of recording layers. If two test areas closer to the outer circumference, of four test areas, are defined as a first pair and two test areas closer to the inner circumference are defined as a second pair, the test areas of the first pair and the test areas of the second pair are so disposed as to be prevented from overlapping with each other in the layer direction. Two test areas of the first pair have the same consumption direction of the test area, and are so disposed that the areas to be used next hardly overlap with each other in the layer direction. Two test areas of the second pair have the same consumption direction of the test area opposite to the consumption direction of the test area in the first pair, and are so disposed that the areas to be used next hardly overlap with each other in the layer direction.

Recordable optical disc, recording device, and recording method

The present invention is to realize a proper inner zone layout in an optical disk having at least three layers. A test area is provided in the inner zone (inner circumference side area) in each of recording layers. The test areas of each layer are so disposed as to be prevented from overlapping with each other in the layer direction. Furthermore, the number of management information recording/reproduction areas overlapping with the test area in the layer direction at a position closer to the laser-incident surface than this test area is set equal to or smaller than one in each test area of each recording layer. The management information recording/reproduction areas are each so disposed as to be prevented from overlapping with the test areas in the respective recording layers in the layer direction on the disk substrate side of the test areas.

Recordable optical disk, recording device, recording method, and reproduction device

Optical disc having specified track pitch, push-pull signal, and cross-track signal

Optical Disc

A phase-change optical disc has a recording layer formed from a phase-change material switchable between a crystalline state and an amorphous state. The recording layer is illuminated signal-wise by a light is focused onto the recording layer to change the phase thereof from crystalline to amorphous, to thereby write an information signal onto the recording layer. The phase-change material contains a GeSbTe alloy. The recording layer is formed by sputtering in an Ar gas atmosphere containing at least either N,or O,gas or both. The optical recording medium exhibits improved durability after repeated recording and maintains a stable and good write/read characteristic even after repeated cycles of signal recording.

Optical recording medium and method of manufacturing the same

Growing community of inventors

Chiba, Japan

Yoshihiro Akimoto