Hitachi Maxell, Limited

Kazuyoshi Adachi

Osamu Ishizaki

Tsuyoshi Maro

Minoru Fujita

Hideo Daimon

Reiji Tamura

Naoki Kitagaki

Hiroshi Shirai

Makoto Iimura

Takeshi Ohnuki

Akira Kashiwakura

Kazuyo Umezawa

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

The present invention provides a magnetic recording medium with distinguished SNR and mechanical characteristics, which comprises an underlayer, a ferromagnetic thin film metallic layer and a protective film layer successively and continuously laminated on a non-magnetic resin substrate, where (A) at least one layer selected from the group consisting of an Si layer, an Si.sub.w N.sub.x C.sub.y O.sub.z layer and an Al.sub.w N.sub.x C.sub.y O.sub.z layer and (B) at least one layer selected from the group consisting of silicides, nitrides, oxides or their mixtures of Ti, Ta, Mo, V, Zr and their alloys are laminated on the non-magnetic resin substrate in the order of (A) and (B) or (i) a layer composed of at least one material selected from the group consisting of Ti, Ta, Mo, V, Zr, Nb and their alloys, (ii) at least one layer selected from the group consisting of an Si layer, an Si.sub.w N.sub.x C.sub.y O.sub.z layer and an Al.sub.w N.sub.x C.sub.y O.sub.z layer (where w+x+y+z=100 at. %, w.gtoreq.30 at. %, 0 .ltoreq.z.ltoreq.50 at. % and x+y.gtoreq.20 at. %), and (iii) a layer composed of at least one material selected from the group consisting of Ti, Ta, Mo, V, Zr and their alloys are laminated on the non-magnetic resin substrate in the order of (i), (ii) and (iii), between the non-magnetic resin substrate and the underlayer.

Magnetic recording medium

A head shutter is mounted on casing of a magnetic disk cartridge to openably cover a head insertion opening, and a spindle shutter is mounted on the cartridge casing to openably cover a spindle insertion opening. A shutter operating member is mounted on the cartridge casing, and is operable from the outside of the cartridge casing. When the insertion openings are closed, the shutter operating member is engaged with the head shutter and the spindle shutter to hold them against their opening movements, and when the insertion openings are to be opened, the shutter operating member is disengaged from the spindle shutter, and also acts on the head shutter to open the head shutter. A shutter opening-closing mechanism is provided in a disk drive unit, and includes a first shutter opening member for operating the shutter operating member, and a second shutter opening member for moving the head shutter from its half-opened position to its fully-opened position.

Magnetic disk cartridge and shutter opening-closing mechanism for the

Growing community of inventors

Toride, Japan

Kazuyoshi Adachi