Ricoh Company, Ltd.

Kei Hara

Shunichi Sato

Yoshinori Hayashi

Yasuo Katano

Daisuke Ichii

Satoru Tomita

Akihiro Itoh

Mitsumi Fujii

Minoru Morikawa

Hiroyoshi Shouji

Naoto Jikutani

Morimasa Kaminishi

A semiconductor stack includes a semiconductor DBR (Distributed Bragg Reflector) formed on a substrate, and a resonator formed on the semiconductor DBR laminating wide-band semiconductor layers and active layers alternately. Each of the active layers includes MQWs (Multiple Quantum Wells) and two spacer layers formed one on each surface of the MQWs. The MQWs are formed by laminating barrier layers and quantum well layers alternately. There are n layers of the wide-band semiconductor layer formed, and a band gap Egof an m-th wide-band semiconductor layer counting from the substrate and a band gap Egof an m&#x2212;1-th wide-band semiconductor layer counting from the substrate satisfy Eg&#x3c;Egwhere n and m are integers greater than or equal to 2, and 1&#x3c;m&#x2266;n.

Semiconductor stack and vertical cavity surface emitting laser

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 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-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 crossing the first direction, are formed with generally equal interval in the first direction.

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

A vertical cavity surface emitting laser (VCSEL) includes a semiconductor substrate, a lower reflecting mirror formed on the semiconductor substrate, and a mesa structure. The mesa structure includes an active layer, a selective oxidization layer that includes a current confined structure, and an upper reflecting mirror. A lower electrode is connected to the semiconductor substrate, and an upper electrode is connected to the upper reflecting mirror. The VCSEL emits laser light perpendicularly to the plane of the semiconductor substrate when an electric current flows between the upper electrode and the lower electrode. The semiconductor substrate is inclined with respect to (100) plane. The active layer includes a quantum well layer having a compressive strain with respect to the substrate, and a spacer layer. The spacer layer has either a compressive strain or a tensile strain with respect to the semiconductor substrate.

Vertical cavity surface emitting laser (VCSEL), VCSEL array device, optical scanning apparatus, and image forming apparatus

A surface-emitting laser device is disclosed that includes a substrate connected to a heat sink; a first reflective layer formed of a semiconductor distributed Bragg reflector on the substrate; a first cavity spacer layer formed in contact with the first reflective layer; an active layer formed in contact with the first cavity spacer layer; a second cavity spacer layer formed in contact with the active layer; and a second reflective layer formed of a semiconductor distributed Bragg reflector in contact with the second cavity spacer layer. The first cavity spacer layer includes a semiconductor material having a thermal conductivity greater than the thermal conductivity of a semiconductor material forming the second cavity spacer layer.

Surface-emitting laser device and surface-emitting laser array including same

A light-heat conversion in a light-stimulated writing method and associated apparatus include an image recording body having an element, which absorbs an (electromagnetic wave) provided in a surface of a recording body, or in a recording layer formed on an uppermost layer of the recording body having a material exhibiting a thermal changeable character of wettabilty, or in a substrate or an intermediate layer of the recording body. After a liquid is disposed on the recording body by a liquid forming device, light-stimulated writing is carried out, resulting on an enhanced efficiency of light-heat conversion by a light absorbing element.

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Miyagi, Japan

Kei Hara