Ricoh Company, Ltd.

Takashi Shibaguchi

Makoto Harigaya

Nobuaki Onagi

Kazunori Ito

Michiharu Abe

Yoshiyuki Kageyama

Hiroko Tashiro

Eiko Suzuki

Hajime Yuzurihara

Hiroyoshi Funato

Eiko Hibino

Hiroko Ohkura

Noriyuki Iwata

Katsuhiko Tani

Yuki Nakamura

Katsuyuki Yamada

Hiroshi Deguchi

Michiaki Shinotsuka

Toshiyuki Inokuchi

Kan Tomita

Akira Shimofuku

Shinya Narumi

Hideo Segawa

Mikio Kinoshita

Fumio Asano

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

An optical recording medium including a recording layer which includes a reversible phase-change recording material, the recording layer being capable of writing information therein, reading written information therefrom, and rewriting written information by utilizing the reversible phase change of the phase-change recording material, wherein when a recording mark formed in the recording layer is repeatedly read 5000 times, using a continuous wave laser beam having such an intensity Pr that satisfies the condition of 1.1&#x2266;R&#x2266;2.0, in which R is &#x3c3;/&#x3c3;as defined in the specification, the optical recording medium satisfies a relationship of d&#x3e;das defined in the specification. The phase-change recording material, a method of producing the optical recording medium, and a method of writing information in the optical recording medium, reading written information therefrom and rewriting written information therein are proposed.

Optical recording medium, recording material, method of producing optical recording medium and optical recording, reading and rewriting method

An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Phase-change optical recording medium and recording method and apparatus for the same

Optical recording medium, recording material, method of producing optical recording medium, and optical recording, reading and rewriting method

An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Cd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

A phase-change optical recording medium has a substrate, and a lower heat-resistant protective layer, a recording layer capable of recording and erasing information by utilizing changes in the phase of a phase-change recording material in the recording layer, an upper heat-resistant protective layer and a light reflecting and heat dissipating layer, which are successively overlaid on the substrate in this order, the recording material including Ag, In, Sb and Te as the main elements, at least one additional element selected from the group (1) consisting of B, C, N, Al, Si and P, and at least one additional element selected from the group (2) consisting of halogen atoms and alkali metal elements.

Phase-change optical recording medium

In an optical beam scanning apparatus having an electrooptic lens, a focal point of a light beam is adjusted to be exactly positioned on a scanning surface by a feedback control at any positions scanned by the light beam during a single scanning period. A deviation of a focal position of the light beam relative to the scanning surface is detected, and a detection signal corresponding to the deviation of the focal position is output. A focusing signal is stored and supplied which corresponds to the detection signal obtained when a focal position of the light beam is exactly positioned on the scanning surface. A differential signal is obtained as a difference between the focusing signal and the detection signal. A level of a driving voltage to be supplied to the electrooptic lens is controlled by a driving voltage controlling signal which is a sum of the differential signal and the focusing signal.

Optical beam scanning apparatus adjusting focal point over entire image

An optical shutter device comprises an electro-optic layer of a material that shows the electro-optic Kerr effect, an array of shutter regions defined on the electro-optic layer for controlling a passage of an optical beam through the layer, a plurality of electrodes provided on the electro-optic layer in correspondence to the shutter regions for applying a predetermined electric field upon energization, a driver circuit connected to each pair of the electrodes for energizing the same independently from each other, a biasing circuit connected to the plurality of electrodes for applying a predetermined d.c. bias voltage thereto, a switching circuit for inverting the polarity of the d.c. bias voltage, a first polarizing device provided above the electro-optic layer for causing a rotation of the polarizing plane of the optical beam in a first angular direction, and a second polarizing device provided below the electro-optic layer for causing a rotation of the polarizing plane of the optical beam in a second, opposite angular direction.

Optical recording system capable of changing the beam size

An electrooptic device which comprises an electrooptic material disposed on an optical axis of an optical beam. The beam is linearly polarized in advance. The electrooptic material has opposed two surfaces in parallel with the optical axis and in both sides of the optical axis. A first electrode pair which is composed of electrode films is formed on the two surfaces of the electrooptic material to perform a lens function. And a second electrode pair which is composed of electrode films is formed on the two surfaces of the electrooptic material to perform a deflection function. The first and the second pairs are disposed side by side with each other along the optical axis.

Electrooptic device

An optical scanning apparatus for scanning a beam of light from a light source over a target surface by a scanning mechanism to form an image on the target surface. The optical scanning apparatus includes an electro-optic lens provided in an optical path between the light source and the scanning mechanism, a plurality of electrodes being provided on top and bottom surfaces of the electro-optic lens for producing an electric field in a direction perpendicular to the direction of the optical path, and a voltage applying unit being connected to the electrodes. The electro-optic lens is made from an electro-optic medium, and has an ingress surface and and egress surface which are ground to exhibit an adequate electro-optic effect. The beam is cast on the target surface to produce a dot having an enlarged diameter in the vertical scanning direction and in the horizontal scanning direction due to the electro-optic effect of the electro-optic medium when the electric field is produced within the electro-optic lens.

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Kanagawa, Japan

Takashi Shibaguchi