Ricoh Company, Ltd.

Mitsubishi Denki Kabushiki Kaisha

Shinya Narumi

Katsuyuki Yamada

Hajime Yuzurihara

Masaki Kato

Nobuaki Onagi

Kazunori Ito

Hiroshi Miura

Hiroshi Deguchi

Eiko Hibino

Takeshi Kibe

Mikiko Abe

Yuki Nakamura

Satoshi Taniguchi

Yoshitaka Hayashi

Noboru Sasa

Toshishige Fujii

Masayuki Fujiwara

Makoto Harigaya

Hiroko Ohkura

Akira Shimofuku

Takashi Shibaguchi

Noriyuki Iwata

Katsuhiko Tani

Akio Uekawa

Hideharu Yasutake

To provide a sputtering target for preparing a recordable optical recording medium characterized by comprising Bi and B and a manufacturing method thereof, a recordable high density optical recording medium using the sputtering target, and a sputtering target which is capable of improving a speed of the film formation for the improvement of productivity, which has a high intensity at the time of the film formation and which has a heightened packing density.

Sputtering target and manufacturing method therefor, and recordable optical recording medium

An optical disc having a transition linear velocity of 8-11 m/s when irradiating continuous light with 11&#xb1;1 mW and a wavelength of 660&#xb1;10 nm using a pickup head with a numerical aperture (NA) of 0.65, and satisfying the following condition:&#x394;|&#x2266;3%where Rb is a reflectance of an unrecorded area, and Ra is a reflectance of the top of an eye pattern after ten cycles of recording. In one recording mode therefor, the disc is rotated at a constant angular velocity so as to have a linear velocity of 3-4 m/s on an innermost track and a linear velocity of 8-9 m/s on an outermost track. In another mode, the disc is rotated at a constant angular velocity so as to have a linear velocity of 5-6 m/s on an innermost track and a linear velocity of 13-14 m/s on an outermost track.

Optical recording medium

The object is to provide an optical recording method improving the recording characteristics and uniformity in a CAV recording on a phase-change optical recording medium, particularly a high-speed rewritable DVD medium, and a phase-change optical recording medium and an optical recording apparatus used by the method. Regarding a recording method for recording on the phase-change optical recording medium where a recording light comprises a pulse string of heating and cooling pulses, and a light for erasing, an irradiation power is controlled by peak power (Pp), bottom power (Pb) and erase power (Pe), at least any one of Pe/Pp, Pp, Pb and Pe is variable from the minimum to maximum recording linear velocities allowed for the medium, and further the irradiation time of each pulse is varied proportionally with clock T corresponding to a recording linear velocity, the present invention provides an optical recording method which performs a recording by varying at least Pe/Pp from a specific recording linear velocity lower than a peculiar recording linear velocity at which the recording linear velocity degrades abruptly showing a local maximum value, and an optical recording medium and an optical recording apparatus used by the method.

Optical recording method of a phase-change optical recording medium having improved recording characteristics and uniformity and optical recording medium and optical recorder used by the method

An optical information recording medium is provided. This medium at least stores information that indicates a maximum recording linear velocity Vh. The medium comprises a substrate having a concentric circular guide groove. This guide grove has land portions and groves portions. At least a phase change type recording layer is formed on the substrate. The recording layer has such a composition and thickness that a dislocation linear velocity V satisfies the relation V&#x2267;Vh&#xd7;0.85.

Optical information recording medium, method of manufacturing the optical information recording medium, and method of and apparatus for recording/reproducing optical information

There is provided a method and a device for recording optical data able to improve recording power setting during recording by means of PWM with a small number of pulses. During the test recording, using a period of a recording channel clock Tw as the minimum unit, marks having different mark lengths of n&#xb7;Tw and n&#xb7;Tw (n&#x3c;n) are recorded with the same number of m (m&#x3c;n) light emitting pulses, while successively changing the maximum power Pw of the recording signals. The recorded marks are reproduced and the mark lengths Tand Tare measured from the reproduced signals. The recording power can be set by evaluating the deviations D=T&#x2212;n&#xb7;Tw and D=T&#x2212;n&#xb7;Tw.

Method and device for recording optical data

A phase-change optical information recording medium in which information can be recorded, reproduced and rewritten and which includes a first transparent substrate having a wobbling guide groove which is spirally formed thereon at a pitch; a first dielectric layer located overlying the first transparent substrate and having an optical thickness of from 80 nm to 200 nm; a phase-change recording layer located overlying the first dielectric layer and having an optical thickness of from 20 to 50 nm when the recording layer is in an erased state; a second dielectric layer located overlying the recording layer and having an optical thickness of from 10 nm to 70 nm; a reflection layer located overlying the second dielectric layer; optionally a third dielectric layer located between the second dielectric layer and the reflection layer; and a second transparent substrate located overlying the reflection layer.

Optical information recording medium

An optical information recording medium including a substrate, a light absorbing layer which is located overlying the substrate and in which marks are formed to store information and a light reflection layer located overlying the light absorbing layer including a crystal, wherein the optical information recording medium satisfies the relationship, Lt/4 &#x2266;Lc&#x2266; Lm, wherein Lc represents the average particle diameter of the crystal of the light reflection layer, Lm represents the minimum length of the marks, and Lt represents the thickness of the light reflection layer.

Optical recording medium having relation between reflection layer and pit length

An information recording method including irradiating an optical information recording medium containing a phase change recording layer on a substrate having a guide groove with continuous light of a laser beam having an erase power level Pe to determine a transition linear velocity Vo defined as a minimum linear velocity above which the following relationship is satisfied: Rr=Ra/Rb&#x3c;1, wherein Rr represents a reflection light intensity ratio, and Ra and Rb represent a reflection light intensity measured after and before the irradiation of the optical information recording medium with the continuous light, respectively, prior to recording information in the optical information recording medium.

Information recording method, information recording device, optical information recording medium, program for recording information and storage medium

An optical recording medium including a substrate having guide groove thereon; a first protective layer located overlying the substrate; a recording layer located overlying the first protective layer; a second protective layer located overlying the recording layer; a third protective layer of from 2 to 9 nm thick located overlying the second protective layer and comprising Si in an amount not less than 35 atomic percent; and a reflection layer including Ag in an amount not less than 95% by weight. An overcoat layer having a glass transition temperature of from 90&#xb0; C. to 180&#xb0; C. is preferably formed overlying the reflection layer. A method for manufacturing the optical recording medium is also provided.

Optical recording medium having protective and/or adhesive layers, and method of manufacture

An optical disc having a transition linear velocity of 8-11 m/s when irradiating continuous light with 11&#xb1;1 mW and a wavelength of 660&#xb1;10 nm using a pickup head with a numerical aperture (NA) of 0.65, and satisfying the following condition:&#x394;R=|Rb&#x2014;Ra|&#x2266;3%where Rb is a reflectance of an unrecorded area, and Ra is a reflectance of the top of an eye pattern after ten cycles of recording. In one recording mode therefor, the disc is rotated at a constant angular velocity so as to have a linear velocity of 3&#x2013;4 m/s on an innermost track and a linear velocity of 8&#x2013;9 m/s on an outermost track. In another mode, the disc is rotated at a constant angular velocity so as to have a linear velocity of 5&#x2013;6 m/s on an innermost track and a linear velocity of 13&#x2013;14 m/s on an outermost track.

An optical information recording medium including a substrate, a light absorbing layer which is located overlying the substrate and in which marks are formed to store information and a light reflection layer located overlying the light absorbing layer including a crystal, wherein the optical information recording medium satisfies the relationship, Lt/4&#x2266;Lc&#x2266;Lm, wherein Lc represents the average particle diameter of the crystal of the light reflection layer, Lm represents the minimum length of the marks, and Lt represents the thickness of the light reflection layer.

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Yokohama, Japan

Shinya Narumi