Sharp Kabushiki Kaisha Corporation

Sharp Corporation

Tomoyuki Miyake

Kenji Ohta

Hiroyuki Katayama

Junichiro Nakayama

Akira Takahashi

Yoshiteru Murakami

Michinobu Mieda

Kazuo Van

Nobuo Ogata

Yasuo Nakata

Toshiharu Inui

Toshiyuki Tanaka

Kunio Kojima

Yoshihiro Sekimoto

Seiichi Nagatome

Junji Hirokane

Hiroshi Fuji

Tetsuya Inui

Takeshi Yamaguchi

Tetsuo Ueyama

Jun Akiyama

Kohji Minami

Junichi Washo

Mitsuo Ishii

Takashi Iwaki

Toshio Tahira

Katsuo Wada

Miyuki Onishi

Shigemi Maeda

Hideharu Tajima

Toshihisa Deguchi

Shigeo Terashima

Nobuyuki Takamori

Toshihiro Tamura

Takahiro Miyake

Tomiyuki Numata

Hideyoshi Yamaoka

Hideaki Sato

Toshio Ishikawa

Masaru Ogawa

Mitsunobu Yoshida

Shozo Kobayashi

Tomokazu Ise

Masanori Ushioda

Nobuyuki Usui

A pickup for a magneto-optical recording medium is provided, which improves quality of reproduced signals by eliminating a phase difference between the polarizations and is capable of coping with magneto-optical recording media of different recording/reproducing systems. A return light beam of light reflected by a magneto-optical recording medium is polarized and separated into &#xb1; first-order diffracted lights through a light-branching diffraction element provided between a light source and an objective lens. The &#xb1; first-order diffracted lights are compensated for their phases through first and second phase compensation elements so that there is no phase difference between the polarizations, and are, further, polarized and separated through the first and second polarization/separation elements, and are received by first and second light detectors. Use of the first and second phase compensation elements having different phase compensation amounts makes it possible to cope with the magneto-optical recording media of different recording/reproducing systems.

Pickup for magneto-optical recording medium

The optical miniaturized module includes a semiconductor laser for irradiating an optical disk with laser light, a diffraction grating for forming a main beam and two sub beams from the laser light, a polarization hologram for dividing reflected light from the optical disk, and a photodetector for detecting the reflected light. The polarization hologram includes a first parting line defined in a direction optically corresponding to a radial direction as the optical disk rotates. A main beam M incident area is divided with a boundary defined by the first parting line. A sub beam A incident area and a sub beam B incident area are each arranged avoiding the first parting line.

Optical miniaturized module, optical pickup device, and optical disk device provided with light source and photodetector

When halting reproduction of an optical disc, the work memory stores identification information of the optical disc and halt position information thereof, and a contents data memory section stores information of reproduction contents. When resuming reproduction, a disc ID recognition section recognizes the identification information of the optical disc, and reads out the halt position information from the work memory, and reproduction operation is carried out from a halt position with the use of the reproduction content stored in the contents data memory section. During this, an initial process of the disc recording/reproducing section is carried out. Thereafter, reproduction from the optical disc starts uninterruptedly. This allows next reproduction of the information storage medium to start from the halt position at which the reproduction is halted. This also shortens latency time from a reproduction start instruction to actual start of the reproduction, when resuming the reproduction of the information storage medium.

Apparatus and method for reproducing information recorded on information storage medium including improved reproduction halt and restart capabilities, and recorded program media for controlling the same

A tilt sensoris provided on a CD optical pickup, and a sub-chassisand a height adjustment mechanismand the like are provided for adjusting the tilt of a DVD optical pickup. A recording or reproduction position is read in by the DVD optical pickupwhile moving the CD optical pickupand the DVD optical pickupalong guide shaftsandrespectively, the amount of tilt of the optical diskat this position is detected by the tilt sensorof the CD optical pickup, the tilt of the laser light axis from the DVD optical pickupis adjusted in accordance with the amount of tilt that is detected, and the amount of tilt of the optical diskis corrected.

Optical disk drive device and method for correcting tilt of optical pickup

A disk cartridgefor a larger diameter, a disk cartridgefor a medium disk diameter, and a disk cartridgefor a smaller diameter contains a magneto-optical disk for a larger diameter, a magneto-optical disk for a medium diameter, and a magneto-optical disk for a smaller diameter having different disk diameters, respectively. Each cartridge: the disk cartridgefor a larger diameter and the disk cartridgefor a medium disk diameter, is provided with at least one sensor holeto recognize a relation in size of a disk diameter with other disk cartridge having a different disk diameter. This makes it possible to provide a disk cartridge and a disk recording and reproducing apparatus which can realize recording and reproducing with high reliability by a single apparatus with respect to disk cartridges, each of which contains a disk-shaped recording medium having a different diameter.

Disk cartridge and disk recording and reproducing apparatus

A disk cartridge having a small size and a sufficient portability. The disk cartridge has a size of 58 mm (L)&#xd7;54 mm (L)&#xd7;4 mm (L), a thickness less than 5 mm and a small area less than a square of 65 mm. The disk cartridge has a notch 10 formed on the insertion side and having a width of 2 mm (L) and a length of 27.5 mm (i.e., a taper portion of 6 mm (L)+a straight portion of 21.5 mm (L)).

Disk cartridge

The magnetic head of the present invention includes a magnetic body in the form of a flat plate, and a magnetic pole in the form of a pillar for applying a magnetic field to a recording medium, which is provided to rise on a portion of the magnetic body which is offset in one direction from a center of the magnetic body, and is provided with a coil around its outer periphery. Thus, the magnetic head has a core of a raised shape which is composed of the pillar-shaped magnetic pole being attached to the magnetic body in the form of a flat plate, making it possible to provide a heat capacity and a heat radiation area required for the core and the magnetic body, respectively, thus adapting to high frequencies. Further, because the magnetic pole is provided on a position which is offset in one direction from the center of the magnetic body, there will be no interference between the magnetic head and the cartridge or mechanical components even when the size of the core is increased due to the core of the raised shape. As a result, less restriction is imposed on a moving range of the magnetic head, thus using the entire recording area of the recording medium.

Magnetic head and magnetic head assembly using the same

A magneto-optical recording and reproduction device includes an optical pickup for irradiating a magneto-optical disk with a laser beam for performing at least one of information recording to a magneto-optical disk, information reproduction from the magneto-optical disk, and information erasure from the magneto-optical disk; a magnetic head for providing a magnetic field to a position of the magneto-optical disk irradiated with the laser beam for performing at least one of the information recording and the information erasure, the magnetic head being located opposite to the optical pickup with respect to the magneto-optical disk where the magneto-optical disk is mounted on the magneto-optical recording and reproduction device; a housing for accommodating the optical pickup; a guide shaft for moving the housing; a suspension for supporting the magnetic head; and an arm for connecting the suspension and the housing. The guide shaft is on a straight line extending in a direction perpendicular to a plane of the magneto-optical disk from the center of gravity of a combination of at least the arm, the magnetic head and the suspension, so as to suppress a vibration of the arm, with the guide shaft being a fulcrum of the vibration.

Magneto-optical recording and reproduction apparatus exhibiting suppressed vibration

A magnetic head of the present invention is to switch a direction of magnetic fields applied to a heated portion in a recording region in accordance with recording information. The magnetic head is composed of a single magnetic pole in a pillar shape and a coil. The magnetic pole is provided on a magnetic base, with one end surface of the magnetic pole brought into contact with the magnetic base. The coil, wound around the magnetic pole, is provided for generating the foregoing magnetic fields. The foregoing arrangement enables suppression of heat generation at the magnetic head, thereby allowing the recording frequency to be set higher, as well as improving the recording rate.

Magnetic head

A reproducing light quantity control method for an optical memory device includes the steps of (1) recording test data on an optical recording medium; (2) reproducing the test data recorded on the optical recording medium by changing a reproducing light quantity in a plurality of light quantity values; (3) measuring a quality value and a signal quantity of each of a plurality of reproducing signals from the test data; (4) selecting an optimum reproducing signal quantity from a plurality of reproducing signal quantities in accordance with quality values of the plurality of reproducing signals so as to decide a target value of reproducing signal quantity; and (5) recording the target value on a target value recording region of the optical recording medium. This method reduces the time required to obtain a target value of a reproducing signal quantity and speeds up an operation from installing of the optical recording medium to finishing of preparation for recording and reproducing.

Reproducing light quantity control method for optical memory device, and reproducing light quantity control device, and optical recording medium

A magneto-optical recording apparatus for recording information in a magnetically induced super resolution medium (e.g., magneto-optical disk) comprising a magnetic head having a magnetic core whose sectional area along a plane parallel to a surface of the magnetically induced super resolution medium is larger than 0.08 mm.sup.2, a heating section for heating the recording layer of the magnetically induced super resolution medium, and a recording section for recording the information in the recording layer of the magnetically induced super resolution medium by driving the magnetic head and heating the recording layer using the heating section. Consequently, both the sensitivity to the recording magnetic field and reproductivity of high-density bits of the magnetically induced super resolution medium can be improved.

Magnetic head with large cross-sectional area core for use with

A magneto-optic memory medium comprising a dielectric film, a magneto-optic memory film, a dielectric film and a reflective film superposed in layers on a light trnasmitting substrate, the magneto-optic memory film being a rare earth-transition metal alloy film having the composition formula of:

Magneto-optic memory medium

An information reproducing apparatus which has a rotative driver for rotating a disc-shaped recording medium, a floating-type head for reproducing information recorded in the recording medium while floating above the disc-shaped recording medium that is being rotated by the rotative driver, and a suspension, made of an elastic member, for supporting the floating-type head. The information reproducing apparatus is characterized in that the floating-type head has a slider which is floated by an air flow that is directed near the surface of the rotating disc-shaped recording medium, and that the slider has a bevelled portion at one side that faces the outer edge of the disc-shaped recording medium such that any contact between the slider and the ridge that exists along the outer edge area of the disc-shaped recording medium is virtually eliminated. Since the slider is virtually free from contacting the ridge that exists along the outer edge area of the disc-shaped recording medium, the storage capacity of the disc-shaped recording medium can be more effectively used.

Information processing apparatus having a floating-type head

First, a recording magnetic field is generated by a magnetic head using a coil drive current a.sub.1, and a first data signal is recorded on a groove of a recording layer of a magneto-optical disk. Thereafter, similarly, a second data signal is recorded on the same groove as above by a coil drive current a.sub.2. In this case, the first and second data signals have different signal frequencies which do not overlap each other. The amplitude A.sub.1 of the coil drive current a.sub.1, is set greater than the amplitude A.sub.2 of the coil drive current a.sub.2. This arrangement permits multiple recording and increases the recording capacity of the magneto-optical disk.

Method and apparatus for magneto-optical recording or reproducing using

A magneto-optical recording device includes a magnetic field generating coil for generating a magnetic field on a magneto-optical recording medium, a power source for supplying a current to the magnetic field generating coil, switching circuit for driving said magnetic field generating coil to supply the current from the power source in the positive and negative directions by alternately forming first and second current paths according to recording information, first correcting circuit which is disposed on the first current path for correcting a transient response of the current amplitude in the positive direction caused by the magnetic field generating coil, and second correcting circuit which is provided on the second current path for correcting a transient response of the current amplitude in the negative direction caused by the magnetic field generating coil.

Magneto-optical recording apparatus having transient response correction

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Nara, Japan

Tomoyuki Miyake