R&D

2017

Improve light out-coupling efficiency of white organic light-emitting diodes (OLEDs)

Yasunobu Higashika, Nobuhiko Kato, Shigenori Murakami, Hiroaki Kitahara, Jiro Fujimori,
Takahito Oyamada

Summary
As a means to improve the light out-coupling efficiency of organic light-emitting diodes (OLEDs), a method of applying the two-dimensional grating structure was examined. We formed the fine periodic structure at the interface between the glass substrate and the transparent anode as the diffraction grating structure. The diffraction at the grating structure improved the light out-coupling efficiency by extracting the light confined in the substrate (substrate mode) and the organic layers (waveguide mode). Using white OLEDs that have the two-dimensional grating structure as the internal light-extraction layer, the light out-coupling efficiency improved 1.9 times in combination with light out-coupling films on the surface.

Terahertz beam steering and direction of arrival estimation

Shinya Kanai, Tomoyuki Miyamoto, Takao Tagiri

Summary
Terahertz (THz) band is a region of the electromagnetic wave that is expected to use for specific measurements or communication systems. Particularly for applying to communication systems, beam tracking technique, such as irradiation direction scanning and direction of arrival estimation of terahertz beam, is needed. In this paper, we report our studies of beam tracking technique, as described above, using resonant tunneling diodes (RTDs) for generating and detecting THz wave. As a result, for the irradiation direction scanning, by implementing the offset irradiation to reflector antenna, the capability for the linear directional scanning was confirmed. Whereas, as to the direction of arrival estimation, applying the estimation method using correlation coefficient to a few data points, capability of the estimation by the five (5) -element RTD curved surface array was confirmed. Finally, the guideline for design of the antenna array for estimation of direction was established.

Robust feature-extraction methods for high-performance image-recognition systems

Toshiaki Inoue

Summary
LBP (Local Binary Pattern), suitable for the robust and low-cost texture classification, is expected to be applied to high-performance image-recognition systems in various areas or fields such as traffic, security, and medical care. In this paper, we describe discrimination improvements of CS-LBP (Center-symmetric LBP) which is one of LBP descriptors. In the conventional methods, features are extracted as binary codes of primary spatial differentials from pixel values, whereas in our new method, binary codes of secondary spatial differentials followed by re-encoding with rotation-invariance relation among all binary patterns is adopted. In the multi-class image-classification tests using our experimental system, the proposed method is effective in various datasets such as generic objects, indoor and outdoor scenes, as well as texture images.

Web Service Development of Sound Simulation

Manabu Nohara, Tomomi Hasegawa, Hisashi Owada

Summary
In the past, only CAE specialists could do a sound simulation. So we have developed a cloud system in order to execute a sound simulation anytime, anywhere and by anyone. This thesis introduces a simulation of sound phenomenon in a car for the car audio development. Sound developers can get the sound information under the internet environment by operating web-oriented UI intuitively.

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