Ricoh Company, Ltd.

Hitachi, Ltd.

Ricoh Research Institute of General Electronics Co., Ltd.

Akihiro Itoh

Shunichi Sato

Naoto Jikutani

Takashi Takahashi

Morimasa Kaminishi

Hiroyoshi Shouji

Kazuhiro Harasaka

Satoru Sugawara

Masahiro Hayashi

Shinji Satoh

Yoshinori Hayashi

Takuro Sekiya

Daisuke Ichii

Akira Sakurai

Kazuya Miyagaki

Mitsumi Fujii

Atsuyuki Watada

Koei Suzuki

Toshihide Sasaki

Ken Kanai

Kei Hara

Masayoshi Katoh

Teruyuki Furuta

Shuuichi Hikichi

Naohito Shimota

Toshihiro Ishii

Katsunari Hanaoka

Kengo Makita

Koji Suzuki

Yuji Suzuki

Hiroaki Matsuda

Tadashi Kasai

Yutaka Takahashi

Mitsuo Aoki

Hiroshi Miura

Bing Shu

Kazuhiko Adachi

Takayuki Koike

Koichi Haga

Yukito Sato

Kazuyuki Yazaki

Takeshi Hino

Takatoshi Yamamoto

Hideki Sano

Shinya Umemoto

Yoshiaki Zenno

Yoshiyuki Tamukai

Jikutani Naoto

Data synchronization requires much time if synchronization is started from an initial state where synchronization between databases is not performed, and when a synchronized record is updated during the synchronization process, synchronization of records must be performed again, so that the amount of communication for synchronization is increased. Therefore, when starting synchronization, data synchronization is performed based on a method using a table indicating the synchronization statuses between databases, and at the final stage of synchronization, data synchronization is performed based on a query transmission method using update logs. The remaining synchronization time is periodically calculated of a case where synchronization is continued via the table method and a case where synchronization is performed by switching to the query transmission method, and the synchronization method is switched if the calculated remaining synchronization time becomes shorter when switched to the query transmission method.

Database management system and method for controlling synchronization between databases

An alkali metal cell is disclosed, including a substrate in which is formed an opening which penetrates from one face to the other face thereof; a first transparent substrate bonded to the other face of the substrate; and a second transparent substrate bonded to the one face of the substrate, wherein an alkali metal is sealed into a space surrounded by the first transparent substrate and the second transparent substrate in the opening of the substrate, wherein, in the substrate and the second transparent substrate, the space is enclosed by a bonding between a first bonding metal layer formed by a first bonding metal and a second bonding metal layer formed by a second bonding metal, and wherein the second bonding metal layer has a bonding temperature higher than that of the first bonding metal layer.

Alkali metal cell, atomic oscillator, and alkali metal cell fabricating method

A surface-emitting laser device includes a transparent dielectric layer provided in an emitting region and configured to cause a reflectance at a peripheral part to be different from a reflectance at a central part in the emitting region. In the surface-emitting laser device, the thickness of a contact layer is different between a region having a relatively high reflectance and a region having a relatively low reflectance in the emitting region. The contact layer is provided on the high refractive index layer of an upper multilayer film reflecting mirror, and the total optical thickness of the high refractive index layer and the contact layer in the region having the relatively low reflectance is deviated from an odd number multiple of a one quarter oscillation wavelength of laser light emitted from the emitting region.

Surface-emitting laser device, surface-emitting laser array, optical scanner, image forming apparatus, and method for manufacturing surface-emitting laser device

An atomic oscillator is disclosed, including an Alkaline metal cell, a light source illuminating a laser beam to the Alkaline metal cell, and a light detector detecting light passing through the Alkaline metal cell. The Alkaline metal cell includes a first member, a second member, a cell internal portion, and an Alkaline metal raw material. In the first member, a first glass substrate is bonded on a second surface of a first substrate where a first opening part is formed. In the second member, a second glass substrate is bonded to a fourth surface of a second substrate where a second opening part is formed. The cell internal portion is formed by the first opening part and the second opening part by bonding the first surface to the third surface. The Alkaline metal raw material is enclosed by the cell internal portion.

Atomic oscillator and method for fabricating atomic oscillator

A surface-emission laser array comprises a plurality of surface-emission laser diode elements arranged in the form of a two-dimensional array, wherein a plurality of straight lines drawn perpendicularly to a straight line extending in a first direction from respective centers of the plurality of surface emission laser diode elements aligned in a second direction perpendicular to the first direction, are formed with generally equal interval in the first direction, the plurality of surface-emission laser diode elements are aligned in the first direction with an interval set to a reference value, and wherein the number of the surface-emission laser diode elements aligned in the first direction is smaller than the number of the surface-emission laser diode elements aligned in the second direction.

Surface-emission laser array, optical scanning apparatus and image forming apparatus

A disclosed method of manufacturing a surface emitting laser includes laminating a transparent dielectric layer on an upper surface of a laminated body; forming a first resist pattern on an upper surface of the dielectric layer, the first resist pattern including a pattern defining an outer perimeter of a mesa structure and a pattern protecting a region corresponding to one of the relatively high reflection rate part and the relatively low reflection rate part included in an emitting region; etching the dielectric layer by using the first resist pattern as an etching mask; and forming a second resist pattern protecting a region corresponding to an entire emitting region. These steps are performed before the mesa structure is formed.

Method of manufacturing surface emitting laser, and surface emitting laser, surface emitting laser array, optical scanning device and image forming apparatus

A surface emitting laser diode comprises a substrate, a lower reflector formed over the substrate, an active layer formed over the lower reflector, an upper reflector formed over the active layer, a current restrict structure including a current confinement region surrounded by insulation region. The current restrict structure is disposed in an upper reflector or between an active layer and the upper reflector, and an upper electrode formed over the upper reflector includes an aperture which corresponds to an emission region from which light is emitted in a first direction perpendicular to a surface of a substrate. The emission region and the current restrict structure including the current confinement region are selectively configured to obtain high single transverse mode, stabilized polarization direction, isotropic beam cross section and small divergence angle, while allowing the device to be manufactured with high yield rate.

Surface emitting laser diode, optical scanning apparatus and image forming apparatus

In a surface-emission laser diode, there is provided, between an active layer and a semiconductor layer that contains Al, Ga and As as major components, a semiconductor layer containing Al, In and P as major components such that the semiconductor layer containing Al, In and P as major components is provided adjacent to the semiconductor layer that contains Al, Ga and As as major components. Further, an interface between the semiconductor layer containing Al, Ga and As as major components and the semiconductor layer containing Al, In and P as major components is coincident to a location of a node of electric field strength distribution.

Surface-emission laser diode and fabrication process thereof

A surface-emitting laser array includes a plurality of surface-emitting laser elements. Each surface-emitting laser element includes a first reflection layer formed on a substrate, a resonator formed in contact with the first reflection layer and containing an active layer, and a second reflection layer formed over the first reflection layer and in contact with the resonator. The second reflection layer contains a selective oxidation layer. The first reflection layer contains on the active layer side at least a low refractive index layer having an oxidation rate equivalent to or larger than an oxidation rate of a selective oxidation layer contained in the second reflection layer. The resonator is made of an AlGaInPAs base material containing at least In. A bottom of a mesa structure is located under the selective oxidation layer and over the first reflection layer.

Surface-emitting laser array, optical scanning device, and image forming device

A manufacturing method for manufacturing a surface-emitting laser device includes the steps of forming a laminated body in which a lower reflecting mirror, a resonator structure including an active layer, and an upper reflecting layer having a selective oxidized layer are laminated on a substrate; etching the laminated body to form a mesa structure having the selective oxidized layer exposed at side surfaces thereof; selectively oxidizing the selective oxidized layer from the side surfaces of the mesa structure to form a constriction structure in which a current passing region is surrounded by an oxide; forming a separating groove at a position away from the mesa structure; passivating an outermost front surface of at least a part of the laminated body exposed when the separating groove is formed; and coating a passivated part with a dielectric body.

Manufacturing method, surface-emitting laser device, surface-emitting laser array, optical scanner, and image forming apparatus

A surface-emission laser array comprises a plurality of surface-emission laser diode elements arranged in the form of a two-dimensional array including a plurality of columns of the surface-emission laser diode elements, each column including therein at least two surface-emission laser diode elements in a first direction. The surface-emission laser diode elements in a column are disposed with an equal interval in the first direction. The plural columns arc disposed in a second direction which is perpendicular to the first direction. An interval between two adjacent columns is larger in a central part than in a peripheral part of the two-dimensional array of the surface-emission laser diode elements in the second direction.

A surface-emitting laser element for emitting light in a direction perpendicular to a substrate, including a substrate with a normal direction of a principal plane inclining toward one direction of &#x3c;1 1 1&#x3e; with respect to one direction of &#x3c;1 0 0&#x3e; and a mesa structure formed on the substrate and having a narrowed structure with an oxide produced by oxidizing a part of a layer to be oxidized selectively, containing aluminum and surrounding an electric current passage area, wherein a cross-section of mesa structure being parallel to the substrate is parallel to a substrate surface and orthogonal to both one direction of &#x3c;1 0 0&#x3e; and one direction of &#x3c;1 1 1&#x3e; and a length in a first direction passing through a center of the electric current passage area is more than a length in a second direction parallel to a substrate surface and orthogonal to the first direction.

Surface-emitting laser element, surface-emitting laser array, optical scanning device, and image forming apparatus

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Miyagi, Japan

Akihiro Itoh