Shintaro Nakano

A large-area flexible wireless power transmission sheet using printed plastic MEMS switches and organic field-effect transistors

We have successfully manufactured a large-area power transmission sheet by using printing technologies. The position of electronic objects on this sheet can be contactlessly sensed by electromagnetic coupling using an organic transistor active matrix. Power is selectively fed to the objects by an electromagnetic field using a plastic MEMS-switching matrix

Low operation voltage of inkjet-printed plastic sheet-type micromechanical switches

We have fabricated plastic micromechanical switches using inkjet printing technologies. By reducing the device dimensions, particularly the spacing between the electrodes for electrostatic attraction, the operation voltage is reduced to 6.6V. The frequency response exceeds 1kHz when the operation voltage is above 20V. When the number of periodic cycles of the rectangular voltage waveforms that are applied to the control electrodes in air exceeds 2×106, the on resistance changes slightly from 25to30Ω, thereby demonstrating the reliability and stability of the present plastic switches.

A flexible, lightweight Braille sheet display with plastic actuators driven by an organic field-effect transistor active matrix

A flexible, shock-resistant, and lightweight Braille sheet display has been successfully manufactured on a plastic film by integrating a plastic sheet actuator array with a high-quality organic transistor active matrix. This is the first demonstration, to the best of our knowledge, to integrate plastic MEMS (microelectromechanical systems) actuators with organic transistor active matrices, which opens up new versatile possibilities for flexible, large-area electronic applications including tactile displays

Hall effect measurements using polycrystalline pentacene field-effect transistors on plastic films

We performed Hall effect measurements using polycrystalline pentacene field-effect transistors manufactured on plastic base films. The field-effect mobility is 0.4cm2∕Vs in a linear regime. We detected a change in the Hall voltage, which linearly increased with the magnetic field (B) and reached 700μV at B=9T. From the evaluations, the Hall mobility was 0.4±0.1cm2∕Vs. Furthermore, we observed that the inverse of the Hall constant was two or three times larger than the amount of charge estimated from the gate voltage, indicating the importance of hopping transport between polycrystalline grain boundaries.

Plastic complementary microelectromechanical switches

We have fabricated plastic complementary microelectromechanical switches by using ink-jet printing technologies. Two vertically stacked regular plastic microelectromechanical switches that are complementary to each other realize the function of an inverter. While rectangular voltage waveforms were periodically applied to the control electrodes in the air, the delay times and durability were examined systematically. The frequency response was 50 Hz for an operation voltage of 60 V. When the number of periodic cycles exceeded 106, the changes in the on resistance of the top and bottom switches were 9% and 43%, respectively.

A 107pJ/b 100kb/s 0.18μm Capacitive-Coupling Transceiver for Printable Communication Sheet

Low-power wireless communications between electronic objects scattered over tables, walls and ceiling will form an infrastructure necessary for wireless sensor networks and ambient intelligence. A data edge-signaling scheme and DC power-free pulse detector allow the realization of a low energy/bit transceiver for use in a communication sheet, which allows the creation of infrastructure for ambient electronics when used together with the wireless power transmission sheet.

A 107-pJ/bit 100-kb/s 0.18-

A novel communication system which simultaneously achieves the mobility of wireless communication and the low-power performance of wireline communication is developed with a printable sheet. By combining meter-scale wireline communication and micrometer-scale wireless capacitive-coupling communication, the proposed communication system enables multiple electronic objects scattered over tables, walls, and ceilings to communicate contactlessly with each other by establishing communication paths without cumbersome physical connections. The transceiver developed for the 20 cm times 20 cm communication sheet features a data-edge-signaling transmitter and a DC power-free pulse detector, thereby achieving the lowest energy of 107 pJ/bit at 100 kb/s in wireless communications at a distance of 60 cm in 0.18-mum CMOS.