Hiroyuki Yagyu

Ideal adiabatic structure LiTaO/sub 3/ pyroelectric microsensor fabricated by sandblasting technique

We have successfully developed a high performance LiTaO/sub 3/ microsensor with ideal adiabatic structure. A finite element method (FEM) was employed to design ideal structure with efficient temperature distribution. The FEM was also employed to reduce a stress concentration of the LiTaO/sub 3/ element. Four infrared detector segments were formed in the LiTaO/sub 3/ element. Each segment, with 500 /spl mu/m square, is thermally isolated by an 100 /spl mu/m wide slit penetrated around the segment using a sandblasting technique. The IR sensitivity per unit area of the developed sensor element is twice that of a conventional type element without slits. Furthermore this small sensor element enables to reduce a size of focusing multi-lens to one-fifth as large as that of the conventional multi-lens. The S/N ration of the developed sensor is five times as large as that of the conventional type pyroelectric sensors such as PZT sensor.

Electromagnetic energy harvester with high efficiency using micro-machining Si springs

The direct force input type of electromagnetic energy harvester with significantly high generating efficiency over 40% has been developed. This high efficiency was realized by using the 1mm-thick uniquely-structured Si springs in the harvester, which was fabricated by D-RIE (deep reactive ion etching) from both sides of a 1mm-thick Si wafer. The harvester showed that the peak voltage was 3.7 V and the output energy on the most adequate load resistance was over 1 mJ at an input energy of 2.7 mJ, resulting in a generating efficiency of 41%.