Hitachi, Ltd.

Hitachi-lg Data Storage, Inc.

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Media Electronics Co., Ltd.

Hitachi Maxwell, Ltd.

Hitachi Global Storage Technologies

Takeshi Nakao

Yoshinori Miyamura

Kyo Akagi

Hisashi Takano

Masaaki Futamoto

Yoshibumi Matsuda

Mikio Suzuki

Fumio Kugiya

Hirotsugu Fukuoka

Takayuki Munemoto

Tokuho Takagaki

Toshio Kobayashi

Shigeru Nakamura

Hideo Tanabe

Masahiro Ojima

Naoki Koyama

Kazuo Shiiki

Masahiro Kitada

Isamu Yuito

Ryoichi Nakatani

Noboru Shimizu

Eijin Moriwaki

Akira Arimoto

Kunikazu Ohnishi

Takeshi Maeda

Masayuki Inoue

Takeshi Shimano

Atsushi Saito

Tohru Sasaki

Hirofumi Sukeda

Toshimitsu Kaku

Kiyoshi Matsumoto

Mariko Umeda

Harukazu Miyamoto

Hiroyuki Minemura

Motoyasu Terao

Hitoshi Watanabe

Toshiaki Tanaka

Hisataka Sugiyama

Yoshio Suzuki

Takeshi Kato

Seiichi Mita

Norio Ohta

Yoshito Tsunoda

Hideki Sawaguchi

Nobuyuki Inaba

Yoshinori Takeuchi

Fumiyoshi Kirino

Tetsuya Fushimi

Kenji Mori

Kensuke Ogawa

Yuzo Yamaguchi

Yukio Fukui

Hajime Aoi

Yutaka Akiba

Takashi Toyooka

Masahiko Takahashi

Tsuneo Suganuma

Kenichi Mizuishi

Toshio Niihara

Yosuke Seo

Masuo Kasai

Yoshihiro Hamakawa

Yasuo Amano

Eiichi Seya

Youichi Kawakubo

Hiroshi Yasuoka

Norio Hosaka

Makoto Aihara

Katuaki Chiba

Toyoji Okuwaki

Nobuo Imada

Hiromi Kita

Atsushi Kazama

Sadatsugi Machida

Nobuyuki Nagai

Wataru Sato

In a laser source module aligning laser beams from laser sources for three colors, red, green, and blue on a single combined beam optical axis, decreasing relative displacements of beam spots of three colors, occurring due to thermal deformation by temperature rise, is achieved by a laser source module including plural laser sources, each incorporating a laser having a laser chip installed on a heat sink and a lens converting a light radiated from the laser into a laser beam, and a beam combining unit aligning the laser beams from the laser sources on a single combined beam optical axis, wherein the lasers in at least two or more ones of the laser sources are arranged so that their laser beams will be decentered toward a same direction on the combined beam optical axis upon displacement of an emission point of the laser chip away from the heat sink.

Laser source module and scanning image display device equipped with such module

A laser light source module includes a housing and a heat sink that is thermally connected to the housing. The housing includes a laser element that emits laser light, a laser holder that is made of metal to hold the laser element, a laser light receiving element that receives laser beam from the laser element, a mirror element that reflects the laser light to scan a screen, an optical element that is disposed on the optical axis of the laser light. The laser holder is thermally connected to the housing with a thermally conductive member. A protrusion is formed on the thermally conductive member. The protrusion and the springiness of the thermally conductive member are used to press the laser holder against the housing in the same direction as the direction of laser light emission.

Laser light source module

Optical beams emitted by optical sources are incident on a mirror surface of a scan mirror in a substantially vertical direction and reflected in a substantially vertical direction by the scan mirror. The mirror surface of the scan mirror is driven to repeatedly rotate two-dimensionally by a predetermined scan angle by a scan mirror drive circuit. A polarized beam splitter causes the optical beam emitted by the optical source to be incident on the scan mirror through a quarter wave plate, and outputs the optical beam that has been reflected by the scan mirror and passed through the quarter wave plate toward the screen. A scan angle expander is arranged on the output side of the polarized beam splitter, whereby the scan angle of the optical beam is increased by N times.

Scan type image display device

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Method for manufacturing magnetic head device

Magnetic apparatus with perpendicular recording medium and head having multilayered reproducing element using tunneling effect

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Magnetic head with conductors formed on endlayers of a multilayer film having magnetic layer coercive force difference

Magnetic disk apparatus including magnetic head having multilayered reproducing element using tunneling effect

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semicondutor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Magnetoresistance effect elements and magnetic heads using the tunneling magnetoresistive effect

A minute optical head is provided so that a light source and one or more photo detector elements are integrated on the same substrate by a simple manufacturing process and may be applied to an apparatus for recording and reproducing recordable optical information. An apparatus for recording and reproducing optical information is arranged to have a minute optical head. A light waveguide layer composed of column semiconductor crystal is formed on a monocrystalline transparent substrate and an active layer is formed on the side of the light waveguide layer. The light beam source is a semiconductor having a vertical resonator formed of a high-reflection film before and after an emitting surface of the active layer so that a light beam is vertically radiated to the substrate. The photo detector element is integrated on the closer portion of the substrate to the light beam source of the semiconductor laser. Further, on the opposed surface of the substrate to the light beam source are sequentially integrated a first transparent layer, a diffraction grating, a second transparent layer, a phase difference generating element, a third transparent layer, a light beam focusing element, a fourth transparent layer, and a slide-resisting protective layer. The slide-resisting protective layer is located closer to and as opposed to the information recording medium.

Optical head and apparatus for recording and reproducing optical information through the use of the optical head

Disclosed is an optical pickup and an optical disc device using the same, each including a laser diode, a photo-detector having a region divided into at least six photo-detection areas, and a diffraction grating disposed between the laser diode and the photo-detector and having a region divided into four areas by cross-shaped division lines. The diffraction grating divides a light beam reflected from an optical disc into four diffracted light beams. A focus error signal in accordance with a knife edge method and two kinds of tracking error signals in accordance with a push-pull method and a differential phase detection method are detected by irradiating the light beams diffracted at the areas of the diffraction grating on the detection areas of the photo-detector and/or at boundary lines therebetween, and arithmetically operating light intensity signals obtained from the detection areas of the photo-detector. As a result, there can be realized an optical pickup and an optical disc device, each of which can be matched with various optical discs different in structure by detecting a tracking error signal in accordance with the push-pull method and a tracking error signal suitable for a read only disc using only one photo-detector. Further, in the present invention, a holographic element can be used as the diffraction grating.

Optical pickup for optical disk apparatus

The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-denisity recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Magnetoresistance effect multilayer film with ferromagnetic film

In an optical head, light from a semiconductor laser is directed through a condensing optical system with a condensing lens onto an optical information recording medium through a transparent substrate in the form of a light spot. A unit for producing a light spot position control signal and a unit able to move the light spot, which supports the objective lens for movement, position the light spot on an information track. Light reflected from the optical information recording medium is directed through a polarized light branching element to a photo detector. Also mounted for movement with the objective lens are a polarization conversion element, arranged between the optical information recording medium and the polarized light branching element in order to change the polarization state of light incident to the optical information recording medium and reflected therefrom and a polarization diffraction grating, the diffraction efficiency of which changes depending on the change in the polarization state of the incident light and the reflected light caused by the polarization conversion element. The light spot control signal is detected from both reflected light diffracted through the polarization diffraction grating and non-diffracted reflected light contained in the light which passes through the polarized light branching element.

Tracking method for optical disk apparatus using diffraction light

A magnetic recording medium, its fabrication method, and a magnetic recording apparatus in which both saturation induction and coercive force of a magnetic film is made high as they are near a surface of the recording medium. A high density information recording can be made higher than 50 kFCI in linear recording density even for spacing around 0.2 .mu.m.

Magnetic recording medium having at least two magnetic layers with easy

Multilayer magnetoresistance effect-type magnetic head

A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein a data signal is recorded in the data recording layer of said recording medium, a servo signal is recorded in the servo signal recording layer located below said data signal recording layer, said data signal is read out using a data magnetic head whereas said servo signal is read out using a servo magnetic head, and the frequency of said servo signal is within the range of the gap-null frequency of said data magnetic head whereas the frequency of said data signal is within the range of the gap-null frequency of said servo magnetic head, and said magnetic head is positioned on the data track on the basis of said servo signal. A method and device of head positioning in an information recording/reading device in which a magnetic recording medium with data tracks for recording information thereon is provided and a magnetic head is positioned on the data track to record/read out the information, wherein the data tracks are discrete tracks in which adjacent data tracks are separated by a groove located therebetween, a data signal is recorded on the data track of said recording medium, a servo signal is recorded on the servo tracks of grooves between said adjacent data tracks, and said magnetic head is positioned on the data track on the basis of said servo signal.

Method of head positioning and magnetic recording disk drive using the

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Sagamihara, Japan

Takeshi Nakao