Hitachi, Ltd.

Other

Hitachi-lg Data Storage, Inc.

Hitachi Maxell, Limited

Junko Ushiyama

Makoto Miyamoto

Yumiko Anzai

Keikichi Andoo

Motoyasu Terao

Akemi Hirotsune

Tetsuya Nishida

Hideki Saga

Tsuyoshi Toda

Masatoshi Ohtake

Hiroyuki Minemura

Harukazu Miyamoto

Yasushi Miyauchi

Toshimichi Shintani

Keikichi Ando

Takeshi Maeda

Takeshi Shimano

Hisataka Sugiyama

Mitsuhide Miyamoto

Atsushi Saito

Hiroyuki Awano

Kouichirou Wakabayashi

Osamu Komoda

Reiji Tamura

Yoshihiro Ikari

Tamotsu Fuchioka

Hiroshi Fukuda

Hitoshi Watanabe

Takahiro Kurokawa

Katsuro Watanabe

Yoshihiro Shiroishi

Atsushi Kikugawa

Yoshiyuki Hirayama

Masukazu Igarashi

Hisae Wakabayashi

A microwave assisted magnetic recording head includes a recording magnetic pole unit that produces a recording field for writing to a perpendicular magnetic recording medium, and a high-frequency magnetic field oscillator that produces a high-frequency magnetic field. The recording magnetic pole unit includes a magnetic core with a write gap portion at which a main recording field component is concentrated, and the high-frequency magnetic field oscillator is disposed in the write gap.

Magnetic head, magnetic recording method and apparatus for controlling magnetic head with spin torque oscillator in a disk drive

In forming a space layer of a multi-formation-layer recording medium, there are provided a medium having a high precision in a thickness of the space layer and its manufacturing process. In the multi-formation-layer recording medium wherein at least two pairs of an information recording layer and a translucency spacer are layered on a substrate having physical patterns composed of an optical spot groove and/or pits on the surface, an average thickness of the translucency spacers in an information zone is 15 &#x3bc;m or less, and a difference in spacer thickness between a minimum value and a maximum value is 2 &#x3bc;m or less.

Multi-information-layer recording medium and manufacturing process

Regarding a signal recorded with a first frequency in a recording area on a specific first recording layer and a signal recorded with a second frequency different from the first frequency in a recording area on a second recording layer which might cause interlayer crosstalk in relation to the first recording layer, a reproducing signal measurement method for a multilayer optical recording medium having at least three recording layers includes reproducing the signal recorded in the recording area on the first recording layer, separating signals recorded respectively with the first and second frequencies, discriminating signal amplitude of the first frequency and a maximum value in signal amplitude of the second frequency, and calculating a signal amplitude ratio between them to measure interlayer crosstalk contained in the signal reproduced from the recording area on the first recording layer. Thus, the interlayer crosstalk quantity caused by unnecessary light can be measured quantitatively.

Reproducing signal measuring method, signal reproducing apparatus, and optical recording medium

A test-write method for accurately and quickly determining recording conditions, and an apparatus suitable therefor. In a 2T-based strategy, recording pulse conditions are determined by separately test-writing an even-number length mark and an odd-number length mark, and then the relative positions of the even-number length mark and the odd-number length mark at the recording pulse start time are adjusted.

Test-write method, information recording method, and information recording apparatus

The object of the present invention is to provide a test writing method for seeking the optimum write power correctly and in a short time under a high speed recording condition in a test writing method and an information recording device for recording information by forming different marks from the unrecorded part by injecting energy onto the recording medium. To achieve the above object, even number length marks and odd number length marks are separately test written in the 2T strategy to seek the respective optimum write power. Due to the possibility of enhancing the precision of test writing, a good recording ability can be obtained.

Test writing method and information recording device

Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Information recording method and apparatus with suppressed mark edge jitters

An information recording method and device for recording information by irradiating an optical information recording medium with an energy beam includes forming a first recording mark by irradiation of a monopulse-shaped energy beam having at least a first power level and a second power level that is higher than the first power level, and forming a space succeeding the first recording mark with a write strategy having a downward pulse of a third power level that is lower than the first power level on a backside of a midpoint of the space.

Information recording method and information recording device

An information recording method of recording information with a high degree of accuracy on a semitransparent recording layer, which is subjected to severe thermal interference, of a multilayered recording medium. A downward pulse is applied to the back half portion of a prescribed space in the waveform of an energy beam used for irradiation when the space is formed. Thereby good recording performance is obtained.

Growing community of inventors

Kokubunji, Japan

Junko Ushiyama