Sharp Kabushiki Kaisha Corporation

The University of Tokyo

Teruhisa Kotani

Yasuhiko Arakawa

Shigemi Maeda

Hideharu Tajima

Noboru Iwata

Masaki Hamamoto

Tazuko Kitazawa

Takanobu Sato

Yoshiteru Murakami

Go Mori

Yasuhiro Harada

Toshihiko Sakai

Tetsuya Okumura

Atsushi Etoh

Tetsu Tatsuma

Takashi Arimoto

A QCL () includes a first electrode (), a first contact layer () that is in contact with the first electrode () and is made of a first compound semiconductor, a second electrode () having a polarity opposite to that of the first electrode (), a second contact layer () that is in contact with the second electrode () and is made of a second compound semiconductor, and an active layer () disposed between the first contact layer () and the second contact layer () and including two or more active layer units. Each of the active layer units includes one or more quantum well layers made of a third compound semiconductor and one or more barrier layers made of a fourth compound semiconductor, and each of the quantum well layers and each of the barrier layers are alternately stacked. The vibrational energies of longitudinal optical phonons of the third compound semiconductor and the fourth compound semiconductor are higher than the vibrational energy of a longitudinal optical phonon of GaAs and lower than or equal to the vibrational energy of a longitudinal optical phonon of AlN.

Quantum cascade laser

A quantum cascade laser includes a semiconductor substrate and an active layer having a cascade structure, in which unit layered bodies, each composed of a quantum well light emitting layer and an injection layer, are stacked, wherein the unit layered body has a subband level structure having an upper laser level, a lower laser level, and a relaxation miniband composed of at least two energy levels with an energy spacing smaller than the energy difference (E) between the upper laser level and the lower laser level, the energy width of the relaxation miniband is smaller than the energy (E&#x2212;E) obtained by subtracting the energy difference (E) from the energy (E) of longitudinal optical phonons, and electrons subjected to the intersubband transition are relaxed in the relaxation miniband and are injected into a quantum well light emitting layer in a subsequent unit layered body.

A nitride semiconductor device includes a GaN substrate in which an angle between a principal surface and an m-plane of GaN is &#x2212;5&#xb0; or more and +5&#xb0; or less, a first intermediate layer disposed on the principal surface of the substrate and made of AlGaN, 0&#x2264;z&#x2264;1, and a second intermediate layer disposed on a principal surface of the first intermediate layer, having an Al content different from that of the first intermediate layer, and made of AlInGaN, 0&#x2264;x1&#x2264;1, 0&#x2264;y1&#x2264;1. A quantum cascade laser includes the nitride semiconductor device.

Nitride semiconductor device and quantum cascade laser using the same

A photodetector including a substrate, a light absorption layer arranged over the substrate, the light absorption layer including a stack including a semiconductor layer that absorbs light of a wavelength having an electric field vector parallel to a normal direction of a substrate surface, a lower contact layer arranged on a first side of the light absorption layer, a lower electrode contacting with the lower contact layer, an upper contact layer arranged on a second side of the light absorption layer, and an upper electrode contacting with the upper contact layer. An uneven structure including polarization-selective shapes of projections or depressions on the second side of the upper contact layer is provided, the shapes of projections or depressions each having a size of a wavelength or less of incident light in the semiconductor layer and half the wavelength or greater and being periodically arranged in at least one direction.

Photodetector

An antireflective structure having a higher antireflective effect compared with those of conventional antireflective structures is produced by a simple process. The antireflective structure () includes a plurality of concavities () each having a plurality of convexities () thereon, and a pitch between the plurality of convexities () and a pitch between the plurality of concavities () are smaller than a wavelength of light incident to the antireflective structure ().

Optical element, and antireflective structure and process for production thereof

A semiconductor light-emitting element according to the present invention includes an InGaN (0.25&#x2266;X&#x2266;0.35) template and a quantum well active layer containing AlInGaN (0&#x2266;X2&#x2266;1, 0&#x2266;Y2&#x2266;1) as a well layer.

Semiconductor light-emitting element

A display control device () disclosed includes (i) a display/non-display video image determining section () that determines, on the basis of (i) video image information about a video image displayed by a display device () and (ii) viewing mode information indicative of a viewer's desired mode of viewing a video image, whether the video image displayed by the display device () is a display video image or a non-display video image and (ii) a shutter operation control section () that closes a right-eye shutter and a left-eye shutter of a liquid crystal shutter () when a video image determined as a non-display video image, which is unnecessary for the viewing mode and which is thus not to be displayed to the viewer, is displayed by the display device (). The display control device () thus closes the right-eye shutter and the left-eye shutter of the liquid crystal shutter () when a non-display video image is displayed by the display device (). This arrangement allows each viewer to view a video image in a mode suitable for the viewer.

Display control device, display control method, display control program, computer-readable recording medium, recording/playback device equipped with abovementioned display control device, speech output device, and recording/playback device equipped with speech output device

An image watching glasses identification device(oror) is an image watching glasses identification device(oror) for identifying a pair of shutter glassesthrough which to watch an image displayed on a display device, the image watching glasses identification device(oror) including: an identification information obtaining sectionfor obtaining an identification information item for identifying the pair of shutter glassesand; a display control sectionfor causing the display deviceto display an identification result associated with the identification information item obtained by the identification information obtaining section. This makes it possible to provide an image watching glasses identification device that is capable of causing, when a viewer watches through the pair of image watching glassesthe image displayed on the display device, the display deviceto display the identification result. The identification result enables the viewer to identify the pair of image watching glasses worn by the viewer.

Image watching glasses identification device, image watching system, pair of image watching glasses, image watching glasses identification program, computer-readable recording medium, and display device

An information recording device in accordance with the present invention obtains drive information of a semiconductor laser which is included in a magnetic head by means of a drive information obtaining section and successively records the information in a drive information storing section. A magnetic head control section controls the magnetic head in accordance with a condition of the semiconductor laser on the basis of the drive information thus obtained by the drive information obtaining section.

Information recording device detecting issues in a laser included therein and a method of controlling the same

A near-field light generating device includes a substrate, a semiconductor laser device, a light absorbing device, and a near-field light generator. The semiconductor laser device is formed on the substrate and emits the laser light polarized in a first direction. The light absorbing device is formed on the substrate to be close to a light emission part of the semiconductor laser device and absorbs light polarized in a second direction orthogonal to the first direction. The near-field light generator is formed on the substrate to be close to a light emission part of the light absorbing device.

Near-field light generating device and optically-assisted magnetic recording device with absorbing waveguide

An ultrasonic motor includes a driven object, a piezoelectric element for driving the driven object, a vibration plate including a notch having an inner peripheral surface of an arc-shaped form having a central angle larger than 180 degrees and being vibrated by the piezoelectric element, and a contact portion made of a material different from that of the vibration plate, having a portion overlapping the piezoelectric element in a plan view and being smaller in thickness than the piezoelectric element, attached to the notch of the vibration plate by press fitting or forced fitting and being in contact with the driven object. Thereby, the ultrasonic motor can have a high shock resistance and a high wear resistance, and can be driven with high efficiency.

Ultrasonic motor and ultrasonic vibrator

An ultrasonic motor has a cylindrical rotor for performing a mechanical output, a plurality of ultrasonic vibrators each having two points in internal contact with the rotor, and a preload mechanism for pressing the ultrasonic vibrators from an inside toward an outside of the rotor, and the ultrasonic vibrators are provided to be rotatable relative to the preload mechanism. With this configuration, an internal contact type ultrasonic motor capable of performing efficient drive by using a plurality of ultrasonic vibrators each in contact with a cylindrical rotor at two points and allowing contact at all contact points without requiring a high machining accuracy can be provided.

Growing community of inventors

Osaka, Japan

Teruhisa Kotani