The Internet of things (IoT) is a hot subject in the society and industry. The number of internet-connected things is estimated to exceed 50 Billion by 2020. Sensors are key enablers in the system from the view point of hardware business. The key factor to create expanding sensor business in the IoT era is quick decision making and lower development cost. One of the solutions will be cooperation, even coopetition. Their importance and the validity are discussed on the basis of implemented national projects.

Application fields and technical trends of wireless sensor network are surveyed. Progresses and subjects of sensor units, micro controller units, wireless communication units and power supply units which compose wireless sensor nodes are discussed. In order to deepen an understanding of practical use of wireless sensor network, “Smart Sensing Modules” which is currently under development are introduced as an example. The future of wireless sensor networks is also argued.

Summary form only given. The network sensing systems connect various sensors by wire in order to collect information measured by each sensor. Although, the wired connection causes certain restrictions regarding with the system installation. Consequently, many kinds of research on wireless sensor network systems have been developed. However, almost all commercialized products utilize a battery as the power source. But, the battery exchange process is needed and therefore the setting condition is restricted, again. Furthermore, the management cost of the battery is troublesome. In order to solve these problems, we have proposed the wireless network sensing system with sensor modules with MEMS sensor and without battery by applying the RFID system for power transmittance. Based on this concept, the unique sensor module SNA-MEMS (smart nano micro electro mechanical systems) is developed for the demonstration. This module is driven by the electric power converted from radio wave at the in-module circuit to realize the battery-less concept by following the RFID standard, ISO 15693 13.56 MHz. The demo-model has a piezoresistive 3-axes MEMS acceleration sensor and consists of eight 1cm x 1 cm ceramic boards those are stacked vertically. Each board is connected to the next boards by soldering between through-hole bus located on outer rim of each board. The electric circuit in the modules has following circuit blocks: antenna, interface, power generation, reception, transmission, sensor, multiplexer, and MPU embedded ADC boards. In this paper, the concept of battery-less and wire-less sensing network with the details of developed sensing module, SNA-MEMS is introduced.

The batteryless accelerometer which follows "ISO 15693 13.56 MHz radio frequency identification (RFID)" has developed with MEMS acceleration sensor which can detect plusmn2G. This module utilizes the radiowave for power feeding and signal communication as RFID. And therefore, the cables for power supply and signal transmission and the battery as a power supply are not required. But a conventional flat loop antenna has the limitation in the direction because it cannot send and receive radiowave when it isn't oriented parallel with an antenna of a RFID reader. We have developed a 3D loop antenna which can communicate in any triaxial direction.

For the first time to our knowledge, a hybrid normal-reverse prism coupler was formed on the bottom surface of a light guide in a LED backlight system to achieve a thin, lightweight, LED backlight system. The hybrid prism coupler (HPC) simultaneously exhibits two functions: extraction of guided light from the light guide and focusing the radiated light from the light guide, corresponding to the optical functions of the prism and diffusive sheets used in conventional LED backlight systems. Therefore, using a HPC eliminates the prism and diffusive sheets that have been indispensable optical elements in conventional LED backlight systems, which consequently reduces the thickness of the LED backlight system by 40% compared with conventional systems.

This paper reports on a new PC mouse device by the use of the micromachined thermal flow sensors. The proposed mouse contains two small flow sensors mounted in two 10-mm-diameter and 3-mm-depth spaces in order to measure its velocity and direction. When the mouse is moved in a direction, air flow is generated because the air tends to stay where it is. Our sensors can detect the wide range flow speed which enables the mouse speed ranging from hundreds to one mm/s. A ball-type mouse is as big as one's palm because the mouse needs sufficient weight of a rubber ball to provide friction force. An optical mouse is smaller but it needs a patterned indented surface and sufficient light reflection from the surface of the desktop. The present flow mouse is as small as an optical one and it can work even on a smooth transparent glass. The results indicate that displacement can be measured with in an error ratio +/$2% at 10, 50,100 and 150 mm/s. This error ratio is good enough for this application

A compact switch/relay with excellent high frequency performance at around 2GHz is developed by adopting a novel non-linear spring structure and high frequency signal line structure.The non-linear spring system applied to an electrostatic actuator of RF MEMS switch/relay increases restoration force for switching reliability. The maximum restoration force can be three times higher than that of a linear spring system actuator. No failure due to restoration force shortage is observed during switching test up to 100 million cycles. The present RF MEMS switch/relay has been shown competitive RF performance over conventional RF switches such as PIN diodes and GaAs MMIC both by the experimental results.

This paper describes an ultra compact and high sensitivity fluidic sensor suitable for measuring flow velocity and direction with the operating principle of detecting flow-induced temperature gradient on the surface. This flow sensor is fabricated utilizing surface micromachining technologies on a silicon substrate. The flow sensor has high sensitivity of flow velocities as high as 0.01m/s. Polycrystalline silicon (poly-Si) film heater and poly-Si/Aluminum thermocouples are adopted on a dielectric thin film membrane thermally isolated from the substrate.

The diversification of information and communication services has brought a variety of communication devices those incorporate radio communication circuits and require the circuit forming elements to be further microminiaturized and upgraded for higher radio frequency and broadband applications. In this trend, the key components are switching elements. Improving their performance is indispensable in order to realize next-generation information and communication services. RF MEMS technology, which combines 3-D micromachining technology and a high-frequency line design, is highly expected to provide a solution in this respect. The technology field has reached to a practical level and, in fact, a variety of key circuit elements are being proposed. In this paper, we propose a novel Single-Pole-Double-Throw (SPDT) RF MEMS switch design for RF signal applications in the 0.05-10 GHz frequency. This new switch is actuated by electrostatic force and restoration force of spring for low power consumption. The Pyrex glass was used as base and cap substrates, and the single crystal silicon was used as movable parts. This device has extremely low insertion loss of -0.5 dB and a high isolation of -30 dB up to 10 GHz. The switch has compact dimensions of 2.8 x 4.8 x 0.9 mm with Chip Scale Package (CSP) structure. The packaging process with glass frit seal is applied to 4-inch processed wafer of RF MEMS switching devices.

We improved the large restoration force of a radio-frequency microelectromechanical system (RF MEMS) switch, which had been a challenge in the practical application of RF MEMS switches, by adopting a non-linear spring system for the electrostatic actuator. When an electrostatic actuator with a movable electrode area of 1.4mm2 was driven at a voltage of 24V, analysis showed a restoration force three-fold greater than that of conventional linear spring systems and a stable signal on–off control action. It was also established from simulation and observation of the RF characteristics in a plastic mold package that the actuator has the ability comparable to or exceeding the characteristics of positive intrinsic negative (PIN) diodes and GaAs metal-semiconductor field-effect transistors (MESFETs).

This paper reports key issues of packaging for sensor and actuator MEMS (Micro Electro Mechanical Systems) devices. In this paper, we focus on the two types of MEMS devices, the sensor MEMS and the actuator MEMS. In the case of sensor MEMS packaging, the thermal stress is the most important in order to prevent the deterioration of its sensitivity. On the other hand, in the case of actuator MEMS packaging, it is important to design the packaging for enhancing the device characteristics.

We reported a novel RF-MEMS switch with an extremely low insertion loss of-0.5 dB and a high isolation of-30 dB up to 10 GHz. The switch was fabricated ultra compact size of 1.8/spl times/1.8/spl times/1.0 mm/sup 3/ with Chip Scale Packaging (CSP) structure utilizing wafer level packaging technology. The wafer level packaging with frit glass makes it possible to mount the device directly on the circuit board without any extra outer package and bonding of wires, which deteriorate the RF characteristics. The package is made from cavitied glass wafer as cap-material and frit glass as seal-material. The device wafer consists of single crystal silicon actuators, a base glass substrate and a cap glass.

本研究では, 極力小さな光走査型イメージセンサの開発を目的として, 前報で報告した2次元光走査機構により走査される光の位置を, 新たな機構要素を付加することなく検知する方法を提案し, その方法を用いた小型走査型2次元イメージセンサを試作し, 性能試験を行なった.その結果, 以下のことが明らかとなった.(1) 小型2次元光走査機構の共振特性を利用した走査位置検出方法を提案し, 必要な温度の設定精度, 駆動周波数の設定精度を明らかにした.(2) 2次元光走査機構を搭載した外形25mm×26mm×15mmのイメージセンサを試作し, 0.1～0.2mmの位置検知精度と0.2mmの検出分解能を得た.(3) 試作したイメージセンサで2次元像を検出し, 良好な像の検出が可能なことを確かめた.本研究開発は, 通商産業省工業技術院の産業科学技術研究開発制度に基づく「マイクロマシン技術の研究開発」の一環として, NEDOから委託を受けた(財)マイクロマシンセンターの再委託業務として, オムロン(株)が実施したものである.

A novel micro focusing optical device controlled by a piezoelectric thin film micro actuator has been presented. This device is provided by bonding two micromachined substrates, which are a glass substrate integrated with a surface emitting light element and a micro Fresnel lens on each surface, and a silicon substrate with a diaphragm type of piezoelectric thin film actuator on it. The surface of the thin film is used as a movable reflection mirror. Focusing is performed by changing position of the mirror surface along the optical axis. In the case of applying the micro lens with 1.3 mm of diameter and 0.33 of N.A. to this focusing device and the thin film actuator capable of several micron displacement, focal point shifting of over 100 mm is obtained. Applying the device to optical senors such as a barcode reader, miniaturization of the light source and high resolution detecting for wide range could be possible.

The silicon micromachined optical scanner integrated with photo detectors and piezoresistor has been developed for highly miniaturized scanning type of optical sensors. The scanner is fabricated with silicon micromachining technologies including IC manufacturing methods. It is capable of scanning a light beam spot two dimensionally and photo detection with the information of where the light beam is being scanned. The scanning angle was over 40 deg. x 30 deg. and the photo sensitivity was 0.5 A/W at 680 nm wavelength.