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Institution

Rohm

CompanyKyoto, Kyôto, Japan
About: Rohm is a company organization based out in Kyoto, Kyôto, Japan. It is known for research contribution in the topics: Layer (electronics) & Signal. The organization has 2948 authors who have published 4934 publications receiving 52784 citations. The organization is also known as: ROHM Co., Ltd. & Rōmu Kabushiki-gaisha.


Papers
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Patent
26 Sep 2003
TL;DR: In this article, the authors proposed a semiconductor light emitting device including a substrate, and at least a first semiconductor layer, an active layer and a second semiconducting layer that are sequentially provided on the substrate.
Abstract: The refractive index of the material for forming a light emitting element, example of the material including a group III Nitride Compound Semiconductor, is relatively higher than that of air; therefore, in order to emit, into air, light generated in an active layer in conventional semiconductor light emitting devices, it is indispensable that its incidence angle from their semiconductor layer into the air is the critical angle of total reflection or less. If the incidence angle is more than the critical angle of total reflection, the light cannot go out into the air, and is totally reflected. In order to solve the problem, the invention is a semiconductor light emitting device including a substrate, and at least a first semiconductor layer, an active layer and a second semiconductor layer that are sequentially provided on the substrate, wherein the second semiconductor layer has a polarity different from that of the first semiconductor layer, and the total area of the first semiconductor layer, the active layer and the second semiconductor layer in side faces where the active layer is uncovered is 5% or more of the area of the upper face which is uncovered at the side of the second semiconductor layer.

753 citations

PatentDOI
Kunihiro Komiya1, Tadayuki Sakamoto1
TL;DR: In this article, a bias acceleration circuit for rapidly increasing the magnitude of a bias voltage in time can be provided in or with the bias circuit, whereby even in case of the capacitance of the capacitor included in bias circuit being increased for improving the power supply rejection ratio (PSRR), the rise in the bias voltage can be increased so that the pop sound which arises when bias circuit is activated can be still diminished.
Abstract: the output amplifiers requiring a bias voltage can be activated or deactivated individually, and a bias acceleration circuit for rapidly increasing the magnitude of a bias voltage in time can be provided in or with the bias circuit, whereby even in case of the capacitance of the capacitor included in the bias circuit being increased for improving the power supply rejection ratio (PSRR), the rise in the bias voltage can be increased so that the pop sound which arises when the bias circuit is activated can be still diminished.

339 citations

Patent
Tatsuji Nakai1
29 Aug 2007
TL;DR: In this article, an H-bridge circuit is connected to a coil of a vibration motor that is to be driven, and a comparator receives Hall signals indicating position information of a rotor of the vibration motor, and converts to an FG signal.
Abstract: An H-bridge circuit is connected to a coil of the vibration motor that is to be driven. A comparator receives Hall signals indicating position information of a rotor of the vibration motor, and converts to an FG signal. A pulse width modulator generates a pulse-modulated pulse signal specifying energization time of the coil of the vibration motor. The pulse width modulator, in a first mode, after commencing start-up of the vibration motor, sets a duty ratio of the pulse signal to 100%, and after that, switches the duty ratio to a predetermined value in accordance with rotational frequency of the motor. In a second mode, the duty ratio of the pulse signal continues to be set to 100%. In a third mode, frequency and the duty ratio of the pulse signal are set based on a control signal of a pulse form inputted from outside. The control signal is used also in switching mode.

339 citations

Patent
Daiki Yagishima1
11 Jul 2006
TL;DR: In this paper, the constant current chopping function and the overcurrent protection function were simultaneously obtained to improve the reliability and safety of a motor drive device, and it was shown that it is possible to simultaneously obtain both functions.
Abstract: A motor drive device ( 1 a ) includes: chopping signal generation means ( 151, 153 ) for generating a chopping signal Sa when drive current of a driver ( 14 ) has reached a first threshold value; chopping signal cut-off means ( 152, 154 ) for cutting off the chopping signal Sa when the drive current has reached a second threshold value which is greater than the first threshold value; and overcurrent protection means ( 16 ) for generating an overcurrent protection signal Se when the drive current has reached a third threshold value which is greater than the first threshold value and its continuation time has reached a predetermined threshold value time. Thus it is possible to simultaneously obtain the constant current chopping function and the overcurrent protection function and to improve its reliability and safety.

338 citations

Patent
12 Sep 2005
TL;DR: In this article, the authors present a semiconductor light emitting device, consisting of a plurality of semiconductor layers, including a first semiconductor layer having a first conductivity, an active layer interposed between the first and the second semiconductors, and a non-conductive distributed bragg reflector coupled to the plurality of layers, reflecting the light from the active layer.
Abstract: The present disclosure relates to a semiconductor light emitting device, comprising: a plurality of semiconductor layers, including a first semiconductor layer having a first conductivity, a second semiconductor layer having a second conductivity different from the first conductivity, and an active layer interposed between the first semiconductor layer and the second semiconductor layer, generating light via electron-hole recombination; a first electrode, supplying either electrons or holes to the plurality of semiconductor layers; a second electrode, supplying, to the plurality of semiconductor layers, electrons if the holes are supplied by the first electrode, or holes if the electrons are supplied by the first electrode; a non-conductive distributed bragg reflector coupled to the plurality of semiconductor layers, reflecting the light from the active layer; and a first light-transmitting film coupled to the distributed bragg reflector from a side opposite to the plurality of semiconductor layers with respect to the non-conductive distributed bragg reflector, with the first light-transmitting film having a refractive index lower than an effective refractive index of the distributed bragg reflector.

333 citations


Authors

Showing all 2948 results

NameH-indexPapersCitations
Chihaya Adachi11290861403
Susumu Noda7667228213
Hiroaki Misawa7053817366
Takashi Nakamura5527911961
Atsushi Tsukazaki5426012598
Hiroyuki Sasabe503419796
Paul Fons4939110174
Hajime Nakanotani431347274
Tomoteru Fukumura4322410362
Kosei Ueno401705392
Hiroaki Ohta361013642
Huazhong Yang353544696
Shigeru Niki332524842
Shogo Ishizuka321713696
Koji Shimazawa322974186
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20221
202137
2020102
2019123
2018126
2017165