ntt research and development 2013 review of activities ... · ntt research and development 2013...

Innovation for New Field NTT Research and Development 2013 Review of Activities

Contents

Innovation for New Field


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Conductive polymer combined with silk fibers for biomedical electrodes Long-Term Recording of Bioelectrical Signals Advanced thin-film materials technology leading to innovative device designs Detachable GaN-Based Thin-Film Devices Visual illusion reveals image-based neural representations of 3D objects in the human brain Toward a New Paradigm for Human Object Recognition Integrated nanophotonics technologies (photonic crystals & silicon photonics) Toward Photonic Network Processing in Chip 3D nanostructures and nanomachine technologies Fabrication of Arbitrary-Shaped Tiny 3D Structures for Utilizing the Mechanical Motion KTN swept light source for high-speed Optical Coherence Tomography (OCT) Real-Time Medical Imaging Using KTN Swept Light Source Laser gas sensing technology for analyzing isotope ratio Investigate Materials Origin by Molecular Fingerprint


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C－1

Conductive polymer combined with silk fibers for biomedical electrodes

Long-Term Recording of Bioelectrical Signals



■ By coating a silk fiber with a conductive polymer, a flexible biomedical electrode is produced that can be used as both a thread and a textile.

■ By devising a fixing method and an additive, biocompatibility, hydrophiolicity and flexibility are improved without degrading tensile strength or conductivity.

■ By using a surface electrode without electrolyte paste, an electrocardiogram can be measured with stability equivalent to that of a conventional medical electrode. The inflammation and discomfort caused by electrolyte paste are eliminated.

■ With an embedded electrode, damage is minimized thus enabling long-term recording.

■ Provision of highly individual medical care including tailor-made diagnoses based on the acquisition of biological information.

■ Feedback system for disease prevention and health improvement.

Features

Application Scenarios

NTT Group Global Advantage This work contributes to the global deployment of health and medical ICT services based on the stable long-term monitoring of human biomedical and physiological signals using novel biocompatible electrodes.

We have developed and characterized string shaped electrodes consisting of a conductive polymer PEDOT-PSS combined with silk fiber. They enable electrical signal collection and transmission from/to living tissue without using any electrolyte paste. They offer a new generation of biocompatible electrodes for biomedical ICT without imposing any stress on the subjects.

PEDOT-PSS Silk (Paste free)

Medical electrode (with electrolyte paste)

Textile electrode (silver coating)

Conventional

PEDOT-PSS silk thread

Silk

Silk fiber is coated with conductive polymer PEDOT-PSS

Skin surface electrode (Electrocardiogram of rat)

50 μm PEDOT-PSS silk thread

Sciatic nerve

1 mm

Active

Resting

Embedded electrode (Nerve action potential)

New

NTT Research and Development 2013 Review of Activities



C－2

Advanced thin-film materials technology leading to innovative device designs

Detachable GaN-Based Thin-Film Devices



■ Detaching GaN-based thin-film devices alone from substrates by utilizing the cleavable nature of the inserted BN (boron nitride), which has a layered structure similar to that of graphite and mica.

■ Easy and damage-free detachment of thin-film devices by mechanical force without any laser beam machining or chemical treatment, which allows for less expensive yet more scalable processing.

■ Substrate recyclability further widens the application field of GaN-based devices and provides an environmentally friendly approach.

■ Extremely thin blue LEDs attachable to things such as walls, windows, and vehicles.

■ A window-attached transparent solar cell that can cut out hazardous UV light while generating power.

■ High-performance power devices free from heat-induced degradation.

Features


NTT Group Global Advantage NTT has developed a groundbreaking process for detaching large-area GaN-based thin-film devices from substrates without using large-scale laser equipment or chemical processing. This achievement has been published in “Nature” magazine and dispatched across the globe.

We have recently developed a novel process for detaching GaN-based thin-film devices (e.g., blue LEDs) from substrates. In this process, an extremely thin and cleavable layer that serves as a perforation line is inserted between the substrate and thin-film device. The detached thin-film devices will serve a wide range of applications such as ultra-thin LEDs and transparent solar cells.

Blue luminescence from a detached ultrathin LED BN

release layer

Visible light

LED

Probe

~ 4 μm thick

UV light

Future usage scene

Transparent solar cell that generates power from UV light

N B

In-sheet (adhesive)

Foreign substrate

AlGaN (300 nm) GaN (2000 nm)

InGaN/GaN quantum wells GaN (110 nm)

Host sapphire substrate Mechanical force

BN

Release & transfer process schematic

Perforation line

Probe




C－3

Visual illusion reveals image-based neural representations of 3D objects in the human brain

Toward a New Paradigm for Human Object Recognition



■ Discovery of a novel visual illusion, in which prolonged adaptation to the image of a 3D object substantially alters the apparent shape and material of the subsequent object.

■ The illusion occurs even when adapting to simple image features. ■ The human visual brain has neural mechanisms that represent 3D

objects as a population of image features. ■ Shape perception and object recognition is possible without 3D

shape reconstruction. ■ Analyzing image features for various objects may enable object

recognition algorithms that are consistent with human perception.

Features


NTT Group Global Advantage By introducing a novel visual illusion, NTT provided the first evidence that the human brain can recognize a 3D object from a population of simple features in the 2D image. This brings a new computational framework for image-based object recognition.

Image technologies for 3D object recognition and presentation are rapidly developing, but it is still unclear how objects are represented in the human brain. NTT Communication Science Laboratories discovered a new visual illusion that dramatically alters our perception of an object's shape and material, and revealed a principle that the brain utilizes simple features in the 2D image to recognize a 3D object. This smart and efficient strategy gives rise to a new approach for human-directed object recognition.

The Object Aftereffect Adaptation After looking at objects with different shapes and materials for a period...

Test Two identical objects are shown.

Percept They appear totally different things.

Percept Test Adapt

Adaptation to 2D features produces aftereffect.

Daily objects can also look different. (apple - pear)

The object aftereffect is robustly observed even when the test object is shown at a location distant from the adapting object. The illusion cannot be explained by mechanisms of classical sensory adaptation.

Human object recognition based on image features

Image features

Statistics

Matching

Input image

Apple!

The human visual system can perceive the shape, color, and even the name of an object from the statistical property of simple image features encoded in the low-level neural sensors. Like recent machine-learning model, this scheme requires only shallow computations.

Low-level visual cortex

High-level visual cortex

Retina

■ Rendering images of highly realistic 3D objects without complex computations for 3D shape reconstruction.

■ Developing fast and easy algorithms for object recognition and image search.




C－4

Integrated nanophotonics technologies (photonic crystals & silicon photonics)

Toward Photonic Network Processing in Chip



■ Silicon photonics enables the fabrication of ultra-small photonic devices based on microfabrication technology of Si semiconductor ICs, and makes fabrication of dense-photonic and photonic-electronic integrated circuits possible.

■ We developed a photonic-electronic integrated WDM receiver on a single Si chip.

■ A photonic crystal (PhC) is an artificial periodic structure that can confine light within an extremely small space of less than 1 micron.

■ We developed a PhC-based ultra-small optical switch, optical RAM (Random access memory), and lasers operating with ultra-low power.

■ Development of large-scale photonic integrated circuit. ■ Ultra-low power consumption of information-processing

equipment, such as network routers.

Features


NTT Group Global Advantage NTT laboratories hold the world’s leading high-precision processing technologies, which derive world-class research outputs.

The power consumption of information processing has dramatically increased recently. We are now investigating ultra-low-power high-speed information processing by introducing a high-density optical network technology on electronic chips. We introduce recent studies on “Silicon photonics” and “photonic crystals” toward optical integrated technology.

Many core processors Network using photonics

Core processor Electric circuit layer

Optical network layer

Photonic crystal

50 μm

Ultra-small laser Optical memory cell

p-InP n-InP

Active layer 5 μm

High-density integration technologies of ultra-small and ultra-low power optical devices

Large-scale photonics fused with CMOS

Photonic routing Smart photonic network chip

Silicon photonics

Photonic chip

Electronic IC

WDM

1 cm

AWG

16ch. PD array

16ch. electric output

Photonic chip

Electronic IC

4-bit optical-RAM




C－5

3D nanostructures and nanomachine technologies

Fabrication of Arbitrary-Shaped Tiny 3D Structures for Utilizing Mechanical Motion



■ The method enabled the first-ever 3D nanoprocessing of semiconductor Si for arbitrarily-shaped structures, using electron beam focusing and dry etching from various solid angles.

■ It is applicable not only for Si but also for various other materials. ■ It enabled the fabrication of a highly sensitive charge sensor as

an application for 3D structures. ■ It allowed a charge corresponding to 150 electrons to be detected

at room temperature. Further minimization is expected to enable single electron detection.

■ 3D packaging of fine structure devices such as sensors and actuators.

■ Microtechnologies and nanomachine technologies. ■ Ultimate performance sensors, nanorobotics, and metamaterials.

- This work was partly performed through the collaboration with the University of Tokyo.

Features


NTT Group Global Advantage NTT Laboratories has uniquely developed a 3D nanofabrication process that is based on electron beam lithography and semiconductor nanomachine technology. The process has been reported in famous international journals and invitations have been received to present it at well known, prestigious international conferences.

Semiconductor nano-processing technology has so far been used mainly for 2D structures. Extending it to high quality, ultimate resolution 3D structures provides more innovative applications for it, such as in nanomachines, nanosensors, 3D packaging, and metamaterials. Here we present a newly developed 3D nanofabrication method and an application for it to nanomachine technologies.

1 μm

101

102

103

104

314.0313.5313.0312.5312.0 Detection Freq. (Hz) S

inga

l (e

lect

ron/

Hz0

.5)

Detecting small numbers of electrons with a mechanical oscillator

Example Si nanostructures

3D EB lithography and etching

Signal from periodic charge modulation

Device structure and vibration mode

Utilizing anti-symmetric vibration

Beam 2

Beam 1

Electron beam (Beam diam.: 7 nm)

Sample Rot.: X-axis

Rot.: Y-axis




C－6

KTN swept light source for high-speed Optical Coherence Tomography (OCT)

Real-Time Medical Imaging Using KTN Swept Light Source



■ (1) Novel material: A technique for fabricating high-quality large KTa1-xNbxO3 (KTN) single crystals.

■ (2) Physical property control: A high-speed optical scanner using the large electro-optical effect of KTN crystals.

■ (3) Free space optical system: Laser oscillation in a broad wavelength range, using an external cavity that include a KTN scanner.

■ (4) Real-time image rendering: High-speed interferometric fringe signal acquisition and processing to construct OCT images.

■ Potential: A high-speed beam scanner as a key device for next-generation displays and laser material processing machines.

■ For Medical: High-speed medical examinations of ocular fundus or inner walls of blood vessels.

■ For Industrial: High-speed inspections of products, such as printed-circuit boards.

■ For Cosmetic: High-speed examinations of skin covered with cosmetic foundation.

Features


NTT Group Global Advantage NTT has successfully developed a high-speed swept light source using novel material technology. Our light source operates at one of the world’s fastest repetition rates, providing high accuracy for practical medical diagnosis and product inspection.

Optical Coherence Tomography (OCT) is a noninvasive cross-sectional imaging technique with high-resolution for biomedical and industrial applications. High-speed KTN swept light source promises OCT image acquisition in a short time. It will offer high accuracy of practical medical diagnosis, reducing the burden on the patient.

High-speed product inspection

(1) Novel material (KTN crystal)

(2) Physical property control

(3) Free space optical system

Cross-sectional image of IC card

For Medical

For Industrial

For Cosmetic

KTN swept light source

Finger print and swept duct

(4) Real-time image rendering

High-speed skin surface examination

Cross-sectional image of human nail

Ocular fundus

High-speed ocular fundus examination




C－7

Laser gas sensing technology for analyzing isotope ratio

Investigate Materials Origin by Molecular Fingerprint



■ Development of an economic method for high-precision measuring of stable isotropic ratio may be possible by using highly sensitive laser gas sensing systems.

■ It is expected to determine the origin of food if stable isotropic ratio data of the food are collected systematically.

■ Environmental or global-warming gas measurement will determine the origin of gases emission.

■ Guarantee of food origin ■ Greenhouse-gas-emission-rights dealings ■ Environmental gas measurement

Features


NTT Group Global Advantage The sensing laser that NTT developed is used worldwide. This laser is the key component for high precision laser sensing systems. We demonstrate that the origin of water can be clearly distinguished.

Even if substances look completely similar, the stable isotope ratio (the fingerprint of the molecule) differs by place of origin or production method. When the “fingerprint” can be analyzed economically, a substance’s origin can be easily determined. This analysis method can contribute to solving social problems, such as global warming or deceptive labeling of food origin.

Even stable isotropic ratio “fingerprint of molecules” of water differs by origin.

- Surveillance of global- warming-gases discharge (Determine fuel origin)

H2O

Minor constituents

- Environmental gas measurement (Determine place of gas emission)

- Guarantee of food origin (Determine food origin)

O H H

O H D

16 O H H

18

Cloud NW


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