Site: University of Tokyo
Department of Mechanical
Engineering for Production
7-3-1 Hongo, Bunkyoku
Tokyo 113, Japan

Date Visited: September 29, 1993

Report Author: J. Giachino



J. Giachino
G. Hocker
L. Salmon


Naomasa Nakajima Director, Department of Mechanical
Engineering for Production; Professor


The JTEC team visited Professor Naomasa Nakajima in his office at the University of Tokyo. Professor Nakajima's laboratory is part of the Research Center for Advanced Science and Technology, which has 100 Ph.D. students, about 70 of whom are company employees. The company employees come to the university one to two days per week for classes. Most of these company students are managers or are at a higher level in their respective companies.

Professor Nakajima's Interdisciplinary Laboratory has seven graduate students from various companies. The laboratory uses many technologies to solve specific problems, with three to four students involved with micromachining.

The drive in the laboratory is to use many technologies to solve specific problems. The objectives of the laboratory are to take a higher level system view, to broaden the bases of technologies, and to diversify beyond just silicon. Professor Nakajima stated that the present state of micromachine technology is immature compared to the required level for commercial products (Nakajima 1993).

The work in his laboratory is driven toward medical applications. One area of work is a light driven micropump (Mizoguti et al. 1992). The target application for this device is in a catheter inside the body, where an optical drive for power is required for safety. The pump consists of an array of microcells, fabricated in silicon via wet chemistry, which have membranes that are actuated by light-heated working fluid. A new system uses an IR diode laser that can penetrate the silicon and eliminates the need for fiber-optic inserts into the cell. The pump can be operated at up to 20 Hz.

Another area of work in the laboratory is photoforming of fine parts (Takagi and Nakajima 1993). Extensive work has been done in developing materials for photoforming. The depth is controlled by using dyes to absorb the light and control the depth of penetration.


Nakajima, N. 1993. "Challenge to New Artifacts: Micromachines." Paper presented at 1st International Symposium on Research into Artifacts.

Mizoguti, H., M. Ando, T. Mizuno, T. Takagi, and Nakajima, N. 1992. "Design and Fabrication of a Light Driven Micropump." Proc. of MEMS. Pp. 31-36.

Takagi, T., and N. Najakima. 1993. "Photoforming Applied to Fine Machining." Proc. of MEMS. Pp. 173-178.

Published: September 1994; WTEC Hyper-Librarian