Fumihiko Nakazawa

A compact and high optical transmission SAW touch screen with ZnO thin-film piezoelectric transducers

A compact and high optical transmission touch screen has been developed using surface acoustic waves (SAWs) oscillated by ZnO thin-film piezoelectric transducers. It has a 98% optical transparency and a narrow frame of 1.4 mm. Therefore, it is ideally suitable for mobile devices, such as PDAs or cellular phones. Utilizing a single-phase transducer (SPT) constructed with a ZnO piezoelectric thin film sandwiched between a lower planar electrode and a comb-type electrode enabled us to reduce the ZnO film thickness to 1/20. The peculiarity of the ZnO transducer is using the local maximum of the electromechanical coupling factor with the SPT structure. It has been found that the hillocks on the lower electrode extremely affects the insertion loss and their suppression can improve the ZnO transducer quality. It is very helpful to introduce our own index, the area ratio of hillocks, to determine whether an aluminum alloy is suitable for the ZnO thin-film transducer or not. This paper describes the ZnO thin film we developed for the new SAW touch screen.

Smart power strip network and visualization server to motivate energy conservation in office

This paper describes an electric power visualization system that is developed to reduce electric power consumption in a large-scale office. A small, simple, and smart power strip is developed for practical use with a newly designed built-in contactless current sensor for each outlet. Electric power visualization server used for data acquisition from each outlet of the smart power strip and for the detection of wasted electric power is also developed. Trial service is done with the developed system in an in-house office with 93 persons and 372 outlets. A 15% reduction in power consumption is measured.

Miniaturized microwave tunable bandpass filters on high-k LTCC with integrated resistive vias as bias-T

This paper describes a MEMS tunable bandpass filter operating in the S band region and featuring a low insertion loss of −2.3 dB and small size of 3.7 mm by 4.1 mm. The tunable filter is based on MEMS-varactors-loaded microstrip resonators and has been directly constructed on a high-k low-temperature-co-fired-ceramics (LTCC) wiring wafer whose dielectric constant is 50, using MEMS-on-LTCC technology. The RF signal paths are isolated from the MEMS driving paths by built-in high-resistivity-vias, leading to low insertion loss. RF power-proof performance was evaluated by applying OFDM signals to the device. The results confirm that MEMS tunable filters are sufficiently linear at cell phone power level.

A multipoint thin film polymer pressure/force sensor to visualize traditional medicine palpations

This paper describes a novel multipoint thin film polymer pressure/force sensor enabling detection of pressure/force pulse wave. The sensor features a high sensibility of 11mv/mmHg along with an extremely thin thickness of 100 μm and a high flexibility to adapt to the radial artery portion. The sensor uses charged cellular polymer as sensing layer, which contains 25 separated sensing dots to avoid signal interaction among these sensing points. The sensor attaches to a persons wrist to detect the radial artery vibration, while a physician palpates the artery vibration with his fingertips on it. The sensor is thin and flexible enough to let the artery vibration transmit through it without spoiling the physicians tactile feeling. That makes it possible to correlate the measured pressure/force pulse wave and the physicians pulse diagnosis in real time. That is useful for objectification and quantification of pulse palpation in traditional medicine.

A wireless motor-condition, precise analysis system using a highly efficient vibration-energy harvester

A wireless motor condition precise analysis system that uses a highly efficient energy harvester is described in this paper. A continuation data sampling is required for the condition analysis of a motor. We developed the technology that makes a vibration energy harvester highly efficient and reduces the energy consumption of the whole system. A battery-less wireless analysis system was created in which the operation and life prediction of a motor was made possible. The original structure of the highly efficient energy harvester was developed using magnetic strain material rods. Electric power is generated using the coils around the rods when the rods are bent by external vibration. Therefore, the efficiency of the energy harvester is raised by optimizing the internal stress of the rods using buffer plates. The energy harvester has a resonant frequency of 90 Hz, a maximum electromotive force of 2.7 V, and a maximum power of 28 mW using 0.5-G acceleration. The wireless motor condition monitoring system includes the energy harvester, an end device, a coordinator, and a PC for data processing. The end device for the monitoring and data transfer is operated using only the electric power from the energy harvester. The monitoring information on the temperature, humidity, supplied voltage, and communication quality every three seconds and for the vibration waveform every five seconds is transmitted to the coordinators by the end device and handled by the PC. This enables for the condition monitoring and fault prediction of the motor.

A highly reliable single-crystal silicon RF-MEMS switch using Au sub-micron particles for wafer level LTCC cap packaging

This paper presents a small packaged, reliable and low-voltage driven RF-MEMS switch for wireless communication. We developed novel fabrication process of an RF-MEMS switch using a PZT actuator without a backside cavity to realize wafer-level-packaging (WLP). We also developed organic-free WLP process using sub-micron Au particles simultaneously to contact electrically and to seal hermetically with a low temperature co-fired ceramics (LTCC) wafer as a cap on a multilevel height RF switch. As a result, we obtained a small packaged SPST switch, which is in the small size of 1.4 × 0.9 × 0.8 mm. The RF-MEMS switch operated keeping a low contact resistance (<;3 Ω) up to 1 billion cycles at a low-power condition (DC 1 mW).

Contactless power sensor for smart power strip networked to visualize energy conservation

There is a growing need for energy conservation through energy consumption in offices that have increased 40% from 1990 in Japan. Previously reported electric-power-consumption measurement systems are small for homes [1-3]. We have developed a practical system for a large-scale office. Simple and low power consumption smart power strip having a fail-free power measurement sensor was developed. System software on a server that collects power consumption data from smart power strip makes these visible to motivate user about energy conservation. A block diagram of the developed system is shown in Fig. 1.

A 3D heterogeneous integration method using LTCC wafer for RF applications

This paper describes the concept, fabrication process technologies and performance of a novel 3D heterogeneous integration method developed for RF applications. This method combines the advantages of LTCC, passive integration and MEMS technologies and is promising for the miniaturization and multifunction of future RF-modules. The basic concept is to form a large-size LTCC wiring wafer, and then to form high-Q passives or MEMS directly on the wafer surface. Other functional devices such as the ICs, SAWs are mounted above the surface-formed devices. LTCC wafer can provide dense interconnects and backside pads to provide input and output paths. All of the fabrication processes are carried out at wafer level, which leads to high productivity. A miniaturized duplexer and a MEMS tunable filter were constructed to demonstrate its feasibility and effectiveness.

Dream Chip Project at ASET

Chapter 9 introduces the results of Japanese national research and development (R&D) initiative of 3D integration technology using through-silicon via (TSV) over the 5-year period from 2008 to 2012. Association of Super-Advanced Electronics Technologies (ASET) conducted the “Development on Functionally Innovative 3D-Integrated Circuit (Dream Chip) Technology Project,” and it was managed by the NEDO organization. The development subjects consisted of thermal management/chip-stacking technology, thin wafer technology, and 3D integration technology, ultrawide bus 3D-SiP, mixed signal (digital -analog) 3D, and heterogeneous 3D technology.

Prescription Prediction towards Computer-Assisted Diagnosis for Kampo Medicine

This paper focuses on the attempt to formulate the prescription prediction logic based on the medical data analysis towards the future computer-assisted-diagnosis for Kampo medicine. We constructed and evaluated prediction models for some frequently-used prescriptions using six kinds of machine learning algorithms including artificial neural network, multinomial logit, random forest, support vector machine, k-nearest neighbor, and decision tree. The possibility of prescription prediction and the necessary amount of data required for robust prediction are clarified.