The Beans of Industry: From MEMS to BEANS

Norihisa Miki (Full-time Lecturer, Department of Mechanical Engineering)

When a car crashes, the airbag deploys, but how does the car know a collision has occurred? How can an inkjet printer that prints beautiful photos accurately and rapidly eject one picoliter (1/1,000,000,000,000 of a liter) of ink? Are you aware of the one million (!) tiny mirrors (*1), each about the width of a human hair, used in televisions and movie theaters?

These are all tiny machines, less than one millimeter in size, called MEMS. MEMS is an acronym for Micro Electro Mechanical Systems and are manufactured using the same microfabrication technology used to make integrated circuits. They are found inside game console controllers (motion sensors) and mobile phones. Applications in various other fields are also anticipated. Figure 1 shows a photograph of the rotating part of a four-millimeter-diameter micro gas turbine, which is expected to be used for portable power sources.

MEMS themselves are hidden and not visible to the naked eye. However, they add new functions and high added value to various products such as cars and mobile phones that incorporate them. For this reason, MEMS are called the "beans of industry" (semiconductors were called the "rice of industry"). And these beans, with their high nutritional value and diverse recipes, are evolving under the name BEANS to make an innovative impact on the future 20 years from now (*2).

BEANS is an acronym for Bio Electro-mechanical Autonomous Nano Systems. By integrating nano and bio technologies with conventional MEMS, we can create unprecedented, innovative devices. For example, by immobilizing microorganisms that absorb CO2 and NOx within MEMS, environmental purification microdevices can be realized. The efficiency of MEMS that convert human motion and body heat into electrical energy can be dramatically improved through nano-fabrication technology. By controlling the nanostructure of metals, it can be applied to ultra-sensitive analysis systems (Figure 2). Research on BEANS has just begun. I am confident that in 20 years, they will surely become the "beans of industry," just as MEMS are today.

*1 See the DLP section on the Texas Instruments Incorporated website (http://www.tij.co.jp).

*2 See Future Devices: BEANS on the Micromachine Center website (http://www.mmc.or.jp).