The Research Reports under the 7th
Micromachine Technology Research Grant
academics and people in the industrial world.
Among the themes selected for the seventh (1999)
research grant, one 1-year research project and six 2-year
research projects carried over from fiscal 1998 have been
completed.
Turn the page for a summary of the research results.

This research grant program started inviting
applications in 1993 as a part of the independent activities
of MMC. The purpose of the program is to assist college
and university staff engaged in basic research on
micromachines, as well as to promote further developmentof micromachine technology and communication between

Subjects for the Micromachine Technology Reserch Grant
Research Project Selected for Fiscal 1999
Leader & Co-Worker

Subjects

PeriodCoordinate Measuring Machine Using a
Parallel Mechanism for Micromachine Parts

1 YearAffiliation

Subjects

PeriodProf. Masao Washizu

Department of Mechanical Engineering, Kyoto
University

Molecular Surgey of DNA based on Microsystems

2 Years

Prof. Kazunori Kataoka

Department of Matenals Science, Graduate
School of Engineering, The University of Tokyo

Research Assoc. Atsushi
HaradaDepartment of Matenals Science, Graduate
School of Engineering, The University of Tokyo

Structural Design of a "Chemical Nanomachine" Based on the Self-organization ofPolymers and Its Application to Targeting
Therapy

2 Years

Research Assistant Prof.
Tooru Ooya

School of Materials Science, Japan Advanced
Institute of Science and Technorogy

Study on Biomedical Micromachine Using
Biodegradable Supramolecular-Assembly

2 Years

Lecturer, Hiroshi Toshiyoshi

3rd Division, Institute of Industrial Seience, The
University of Tokyo

Micromachine System for Micro-optical
Smart Pixel Application

2 Years

Prof. Hiroyuki Fujita

3rd Division, Institute of Industrial Seience, The
University of Tokyo

Prof. Shigefumi Nishino

2nd Division, Institute of Industrial Science, The
University of Tokyo

Research Assoc. Kiyoshi
Takano2nd Division, Institute of Industrial Science, The
University of Tokyo

Experimental Study on Fluid Flow and Heat
Transfer inside Microchannels Utilizing
Micromachining Technology

2 Years

Prof. T. H. Barnes

Physics Department, University of Auckland, New
ZealandLow Noise Feedback Interferometry for
Micromachine Servo Actuators

2 Years

Assoc. Prof. Takaaki Oiwa

Affiliation
Faculty of Engineerring, Shizuoka University

Carried-Over Projects Selected for Fiscal 1998
Leader & Co-Worker

Application Guidelines for the 9th (Fiscal 2001)
Research Grant Themes on Micromachine Technology
1. Objective of the research grant

5. Qualifications

Basic research on basic technology, functional element
technology, and systematization technology for
micromachines

College or university faculties (professors, associate
professors, lecturers and research associates) who
belong to academic societies affiliated with theFederation of Micromachine Technology

2. Research period

6. Other

Theme A : April 2002 - March 31, 2003, orTheme B : April 2002 - March 31, 2004

(1) Total funding granted : Approximately 10 million yen(The upper limit for a single research project is 2
million yen for theme A, and 3 million yen for theme B.)(2) After the grant is decided, we may ask recipients tocarry out their research in collaboration with supporting
member enterprises of the Micromachine Center, as
one of the objectives of this project is to encouragecommunication between enterprises and academics.
(3) Contact : Research Department, Micromachine Center
Person in charge : Hodono
E-mail : hodono@mmc.or.jp

3. Application period, theme decision, and funding
grant date
Application period : July 10 - October 31, 2001
Theme decision : Middle of March 2002
Funding grant date : End of March 2002

4. How to apply
Send a fax requesting the application form to theMicromachine Center. Be sure to include your own fax
number or a fax number where we can contact you.
Micromachine Center Fax : +81-3-5294-7137

5

Coordinate Measuring Machine Using a
Parallel Mechanism for Micromachine Parts
Takaaki Oiwa
Associate Professor,
Faculty of Engineering, Shizuoka University
1. Introduction
As the formation of high-precision micro-parts having complex 3D
shapes is becoming feasible, there is increasing necessity to perform
precise 3D evaluations of such parts. Rather than using mechanisms
based on the conventional rectangular coordinate system, we proposed a
new 3D coordinate measuring machine (CMM) using a parallelmechanism in which active pairs are set in parallel with an output link.
In the present study, we will develop a small parallel µCMM using such amechanism. This paper will give a brief outline of this device and reporton the results of studies on the link layout, as well as the trialmanufactured prismatic links (struts).
2. Outline
Fig. 1 shows a conceptual diagram of the parallel µCMM, the basic
design principles of which are described below.
(1) A link mechanism consisting of a parallel mechanism with 3 degrees
of freedom (DOF) is used in place of the mutually orthogonal slide
mechanisms using the rectangular coordinate system.
(2) While the spherical joints are the basic form of reference for
conducting precise measurements, calibration is performed based on
displacement sensors built into the strut that measure the rotational
error of the joint.
(3) The link layout is designed as a retracting mechanism to improve themeasuring resolution in relation to the scale resolution. Therefore,
the mechanism is larger in relation to the measuring space.
(4) The link layout is optimized to eliminate the effects of joint
rotational error and error in the mechanism's parameters on
measurement precision.

stage radius, probe length, and position on the measuring space along
the Z-axis were set as design variables. Fig. 2 shows the layout of thelinks for the parallel µCMM based on this design. The actual size of theparallel µCMM is expected to be about 1/2-1/5 the dimensions given in
the diagram.

Fig.2 Link configuration after optimal design

4. Prismatic Links
Next, an outline will be given for the trial prismatic links. Fig. 3
shows a photo of the link. An inchworm mechanism having a layered
piezoelectric element was used as the actuator. The theoretical drive
resolution was set to 2nm or less. An advanced linear measuring unit
(scale) having a precision of ±0.1µm and a resolution of 2nm or less isalso built into the link. Velocities were measured when applying a load in
the form of weights having masses of 10-400g. From thesemeasurements, it is clear that the velocity is nearly proportional to thesize of the load, and the links have a thrust of more than 4 N per link.
Next, positioning with closed loop controlwas performed using themeasuring unit as a feedback sensor. The time required for performing a
10-µm step positioning process was within 0.1sec.

Actuator andlinear scale
Frame
Automatic probechanger(3D touch probe,
tools, etc.)

Spherical joint
Prismatic joint
Universal joint

Workpiece

Probe

Workspace: 20 x 20 x 20mm

Fig.1 µ-CMM using a parallel mechanism

Fig.3 Photo of the trial-manufactured prismatic link

3. Link Layout Design
The link layout was studied to reduce the effects of errors inparameters and joint rotation on movement of the probe in order tofurther improve measuring resolution. We used singular values in a
Jacobian matrix as a function for expressing the magnitude of the above
effect. For purposes of comparison, the radial position of the sphericaljoint on the base and the size of the measuring space (100 ◊ 100 ◊
100mm) were set equivalent to the conventional parallel CMM. The

5. Conclusion
As described above, we proposed a small 3D CMM employing aparallel mechanism of 3 DOF with the aim of measuring the dimensions
and geometric deviation of 3D parts, such as micromachine parts. The
link layout was designed and trial prismatic links were manufactured andevaluated. Future plans call for studying the effects of the elastic
deformation and rotational error in the joints unit on thermal
deformation of the links.

6

Molecular Surgery of DNA
based on Microsystems
Masao Washizu
Professor,
Department of Mechanical Engineering, Kyoto University
base sequence. Cutting occurs the moment the particles contact the DNA.
In Fig. 2 III), restriction enzymes are immobilized on the particles forrecognizing and cutting a specific sequence. In this case, cutting occurs
only when the particles contact the sequence to be cut (see Fig.2 III b).
3. Developing Microprobes for Molecular Surgery
In order to perform molecular surgery at a high resolution, wedeveloped a probe for molecularparticles
manipulation, as shown in Fig. 3. The Latex(1-3 µm in diameter)
probe is formed of a substrate having a
sharp point and three or more sphericalparticles fixed to the top surface of theprobe. By retaining the particles on the
Substrate
substrate independently by a laser beam,
Pointed tip
the probe is designed to push its pointed
tip, on which enzymes are immobilized, Fig.3 Microprobe for manipulating
molecules
on a desirable position and at a desirable
orientation. The probe is first manufactured as a cantilever structure by
performing Si anistropic etching on the substrate. The micro-particles arethen fixed to the substrate by a molecular linker, and the structure isbroken off at the root.
Fig. 4 shows an example for controlling the orientation of the probe.
By deflecting a single laser beam at a high rate of speed using agalvanometer mirror, each of the three particles are trapped through atime-division method. Translational and rotational movement of theprobe is then achieved by moving the micro-particles while maintaining
their relative positions to one another.
4. Conclusion
Micromachine technologies, such as micromachined electrodes andmicromachined probes, are powerful means for interfacing with themolecular nano-world and macro-world. Based on our current direction,
we anticipate breaking away from conventional biochemical methods, inwhich molecules are collected in a test tube base, and developing new
biotechnologies capable of performing deterministic manipulation on
specific molecules at specific positions.

1. Introduction
In recent years, research has intensified on µ-TAS and other such
systems that fabricate chemical systems to be integrated on a chip.
Although µ-TAS in its present state is not really micro-sized, the samples
are provided in an aqueous solution, that is, as a bulk sample. Hence, byfurther miniaturizing these systems, we should be able to develop an
ultimate chemical system capable of treating molecules individually. DNA
is thought to be the most suitable target for manipulation on themolecular level, because DNA molecules contain the fundamental
blueprints of life and can easily multiply molecules. In the present study,
we researched a method of "molecular surgery" for fixing a single DNA
molecule to a fixed surface in order to cut or otherwise alter the molecule.
2. Molecular Surgery of DNA
Just as a patient is fixed to an operating table in normal surgery, theDNA molecule, which is the target of our molecular surgery, must also be
fixed to a surface. It is also necessary to stretch the DNA molecule in a
linear shape in order to access the desired location. The author andothers developed a method using the electrostatic field in a
micromachined electrode to stretch the DNA and anchor the ends of themolecule. As shown in Fig. 1, enzyme cutting at a specified position isachieved by laser-manipulated micro-particles on which DNA-cutting
enzymes are immobilized.
Micro-particles with immobilized DNA-cutting
enzymes (DNase)
Micro-particles on which enzymes areimmobilized are retained by laser
manipulation and applied to a stretchedand fixed DNA molecule
DNase
Electrode
Stretched and fixed DNA molecule

Fig.1 Conceptual drawing of DNA molecular surgeryI) Mechanical cutting by
non-modified particlesa)II) Cutting by particles with III) Cutting by particles withimmobilized restriction enzymes
immobilized DNaseI
Particles with immoa) bilized DNasel

l-DNA

a)

b)

b)

b)

Electrode

Electrode

Electrode

15µm

l-DNA

d) Rotational movement to the right

Probe

Particles withimmobilized Hind III

l-DNA

Latex particlesa) Translational movement upward

15µmb) Translational movement to the righte) Translational movement to the leftc) Translational movement downwardf) Trajectory of the above movement

Electrode

15µm

Fig.2 Molecular surgery of DNA

Fig. 2 shows photos of the cutting operations. In Fig. 2 I), latex
particles on which enzymes are not immobilized are pressed against theDNA. Mechanical cutting does not occur until the DNA has stretched 1.5
times its natural length. In Fig. 2 II), DNaseI are immobilized on particles
that are pressed against the DNA for cutting the DNA without relation to its

10µm

Fig.4 Translational and rotational movement of the probe

7

Structural Design of a "Chemical Nano-machine" Based on the Selforganization of Polymers and Its Application to Targeting Therapy
Kazunori Kataoka, Professor,
Atsushi Harada, Research Associate,
Department of Materials Science, Graduate School of Engineering, The University of Tokyo
1. Introduction
The capacity to work effectively in microspaces is important in thefield of micromachine technology. Focusing from such viewpoint, there
are many kinds of available molecules in nature. Enzymes, for example,
serve as a biological catalyst that, when catalyzed under mild conditionsin an organism, can generate numerous organic reactions withphenomenal speed and selectivity. Hence, enzymes can be considered atype of natural micromachine. However, their use in vivo often limited
due to their instability and antigenicity. In particular, solving these
problems is a major issue in the field of site-specific enzyme delivery. In
this study, we prepared core-shell type multimolecular assembly
entrapping enzyme molecules in the core (see Fig.1), which were formed
from the mixture of charged block copolymer (polyethylene glycolblock-poly a,b-aspartic acid) with an enzyme (egg white lysozyme)
driven through electrostatic interaction in an aqueous solution. We
studied the utilities of the "chemical nano-machine" to perform
appropriate biochemical reactions under various conditions.
poly (ethylene glycol)-block-poly(a,b-aspartic acid)Egg white lysozyme

Bacterial cell
+NaCl
-NaCl

Lysozyme
ON state of enzymatic activity

Transmittance at 450
nm (%)

OFF state of enzymatic activity

60
50

NaCl 150mM

40

NaCl 0mM

30

NaCl 18.75mM

20
10

0

120

240

360

480

Time (sec)

600

720

Fig.2 On-off control of enzymatic activity synchronizing
with reversible formation by an external stimulus

the assembly, was used, and enzymatic activity was evaluated through themonitoring of the release amount of p-nitrophenol. Fig.3 shows the resultsof observing the generation of p-nitrophenol directly after combining the
enzyme by itself and entrapped in the assembly with the substrate solution.
These results showed that an enzyme reaction occurs even when the
enzyme is entrapped in the assembly. Interestingly, the reaction rate of
enzyme in the core of the assembly was twice as fast with free enzyme. By
determining the kinetic constants of enzymatic reaction, it was confirmedthat the enhanced effect of enzymatic reaction was induced by the effective
condensation of the substrate to shell-layer of the assembly. Hence, theshell-layer might work as a reservoir for the substrate. This suggests thepossibility of further encouraging the enzyme reaction without chemicallyconjugation of the enzyme with polymers, by increasing the affinity of thesubstrate and the shell-forming segment.

Enzyme-entrapping core
Shell : PEG

Several tens
nanometers

Fig.1 Chemical nano-machine entrapping enzyme in the core

2. Environmental-Responsive Chemical Nano-machines
We confirmed that core-shell type multimolecular assembly
entrapping enzyme in the core, as shown in Fig.1, exhibited a reversible
formation with the change in the ionic strength (NaCl concentration) in
the aqueous solution. Enzyme was entrapped in the core at a low ionicstrength, but was released from the assembly when the ionic strength wasincreased. The enzyme once again returned to the core of the assembly
after the ionic strength was lowered. It was applied this behavior as onoff control system of enzymatic reaction. In order to evaluate enzyme
activity, a substrate (bacterial cell) with larger size than the assembly wasused. There observed no activity, when the enzyme was entrapped in theassembly (low ionic strength), since the enzyme could not interact withthe bacterial cells. However, increasing the ionic strength, the enzyme
was released from the assembly and could easily interact with thesubstrate, at which enzyme activity was shown (see Fig.2). It was also
confirmed that this process was repeatable, and enzymativactivity could
controlled through the reversible formation of core-shell type assembly.
3. Chemical Nano-machine System Using the Core of Assembly
as Enzymatic Nanoreactor
As mentioned above, the enzymatic reaction is controlled through thereversible formation of the assembly. Such assembly has another possibility
as applied material by using the core of the assembly having the structure
shown in Fig.1 as an enzymatic reaction field. Thus, it was evaluated the
enzyme activity of lysozyme in the core of the assembly. In this evaluation,
the substrate with relatively small size, which could diffuse into the core of

Release amount of
p-nitrophenol (10-6 mol)

5.0
4.0

Enzyme in the core

3.0
Enzyme

2.0
1.0
0.0

0

50

100
150
Time (sec)

200

250

Fig.3 Release profile of p-nitrophenol with enzymatic reaction
using the core of the assembly as a reaction field

4. Conclusion
Using self-organization between an enzyme and a synthetic polymer, we
prepared multimolecular assembly with an average particle size of 50 nm
having a core-shell structure for entrapping the enzyme. The formation of theassembly exhibited a reversible behavior that could be controlled by external
stimuli (modifying the ionic strength). It was confirmed that such external
stimuli can be used to turn the enzyme activity on and off. We also confirmedthat the core of the assembly could be used as a nanoscopic enzymatic
reaction field. Based on such interesting behavior, the assembly could be
aptly named a "chemical nano-machine." This system shows great promise
not only in enzyme targeting, but in various fields as a diagnostic tool.

8

Study on Biomedical Micromachine Using
Biodegradable Supramolecular- Assembly
Tooru Ooya
Research Assistant Professor,
School of Materials Science, Japan Advanced Institute of Science and Technology
1. Introduction
Recently there has been a general trend of growing expectations throughout theworld in the fields of nanoscale science and nanotechnology. Strategic approaches
are important in the design of biomedical micromachines for controlling molecularforms from nano to micro level. This study focuses on the supramolecular structure
and cylindrical shape of polyrotaxanes, in which numerous alpha cyclodextrins (aCDs) are threaded onto a polyethylene glycol (PEG), to investigate the effects of aparticular polyrotaxane structure on the function of molecular recognition.
2. Enhanced Enzymatic Recognition by Supramolecular
Structure of Polyrotaxanes
In synthesizing the polyrotaxane, a peptide sequencephenlyalanylglycylglycine (FGG) is introduced at the ends of thepolyrotaxane as the oligopeptide group. FGG itself can be completelydegraded by an exo-peptidose, such as aminopeptidase M (AP-M). From
the result of in vitro experiment, it was found that FGG in FGGterminated PEG that had not been threaded through the a-CD cavity
degraded only 30%. This indicates that increased while molecular weight
due to conjugation of FGG and PEG are chemically bonded andinteraction between the AP-M and FGG terminals. On the other hand,degradation of FGG-terminated polyrotaxane completely proceeded,
indicating that the interaction increases again due to a-CD threading
through the PEG (see Fig.1). Since the Km value was about 1/22 of the
FGG-terminated PEG, it was suggested that the supramolecular structureof the polyrotaxane actually improved the enzymatic recognition.

Polyrotaxane

BiotinStreptavidin

Vibro-Stirrer

Cuvette Body

Immobiiized sample layer
Gold film

Prism

Laser

Detector

Fig.2 Image of polyvalent interaction between a polyrotaxanebiotin conjugate and streptavidin in a surface plasmon
resonance (IAsys, Affinity Sensors)and Dr Ikumi Tamai of Kanazawa University, Department ofPharmaceutical Sciences. A dispeptide of varyl-lysine (Val-Lys) that istransportable via peptide transporter (PepT1) was introduced into
numerous hydroxyl groups of polyrotaxane. PepT1 is well known to be
expressed in the small intestine on the brush border membrane ofintestinal epithelial cells. In the in vitro experiment, we studied thecapacity of the polyrotaxane cylindrical structure of the synthesized ValLys-polyrotaxane conjugates to inhibit transporting (uptake) of a
dipeptide derivative (glycylsarosine; GlySar), which is specificallyrecognized by the PepT1. It was confirmed that the conjugate included
about 46 molecules of Val-Lys in one molecule of polyrotaxane. The
uptake of GlySar was decreased by adding this conjugate to a Hela cell
culture medium in which PepT1 was stably expressed. When convertingthe concentration of Val-Lys to the same concentration of Val-Lysintroduced dextran or Val-Lys-introduced a-CD, the inhibition is weaker
than when using Val-Lys-introduced polyrotaxane. This suggests thatthe cylindrical structure of the polyrotaxane is effective in theinteraction between Val-Lys and PepT1. Therefore, it is suggested that
Val-Lys in the conjugate polyvalently interacts with PepT1 (see Fig.3).

Threading of a-CD(%)
033.5±2.5
025
50
75 100Cleavage of Phe-Gly bond(%)

Fig.1 The effects of a-CD threading on the terminal tripetide
degradation by aminopeptidose M

3. Recognition of polyrotaxane-Biotin Conjugates
Approximately 300-400 hydroxyl groups exist along the cylindrical structure
in one molecule of polyrotaxane. If numerous water-soluble ligands are
introduced, it is expected that the ligands become oriented along the cylindricalstructure of the polyrotaxane. Based on the hypothesis biotin was introduced
into the polyrotaxane and its interaction with streptavidin (SA) precoated on thesurface of a sensor was analyzed using a surface plasmon resonance (SPR)
appratus. From the SA binding curve during the coating process, the surface
density of the SA was estimated at 2.5 ◊ 10-5 nmol/mm2. Based on a theoreticallength estimated on the presumption that the polyrotaxane-biotin conjugate iscylindrically shaped, a polyvalent interaction such as that shown in Fig.2 isconsiderable. The biotin introduced into the polyrotaxane was recognized by SA
which was confirmed from the binding curve when adding the solution containing
the polyrotaxane-biotin conjugate. This demonstrates that molecular designs
introducing ligands in cylindrical structures of polyrotaxane can be used asprobes for recognizing specific receptors.
4. Inhibiting Peptide Transporter (PepT1) function by
Dipetide-Polyrotaxane conjugatesThis work was carried out collaboration with Professors Akira Tsuji

Dipeptide
O OH

O

OH

O OH

O

OH

O

H
H
N
N
+
-OOC
O NH3
O Varyl-lysine(VK)

HO

Lumen
O

O OH

O

pH5.5~6.8

PepT1

H+
Intestinal EpitheliumFig.3 Illustration of Inhibiting transport of dipeptide is inhibitedby polyvalent interaction between a polyrotaxane-VK
conjugate and PepT1

5. Conclusion
The above results indicate that the supramolecular structure andcylindrical shape of the polyrotaxane is useful for (1) forming an
enzyme-substrate complex and (2) controlling receptor recognition.

9

Micromachine System for Micro-optical
Smart Pixel Application
Hiroshi Toshiyoshi, Lecturer,
Hiroyuki Fujita, Professor,
3rd Division, Institute of Industrial Science, The University of Tokyo
1. Introduction
We designed and manufactured two-dimensional micro-mechanicaloptical scanners and evaluated their properties with the aim of applying
smart pixels in optical communication switching. Smart pixels are used
to integrate mechanical, electrical, and optical devices in a micro threedimensional space.
2. Micro-mechanical Smart Pixels
Fig.1 shows a conceptual view of a micromachine system, the objectiveof the present study, employing smart pixels to integrate micro-mechanical(MEMS) elements. This system includes an array of optical input fibers andoptical beam steering elements (scanners) using micromachines. The
optical switching function is achieved by projecting an optical beam onto
corresponding output ports. As shown in the diagram, a lens, diffraction
grating for wavelength selection, and filter are inserted between the input
and output fibers to magnify the beam scanning angle.
MEMS beam steering device

MEMS beam steering device

Input port fibers

Output port fibers

Max Distortion 0.33%

Position Y mm

1
100%
0

F

S
M

-1
-1

0
Position X mm

1

Fig.3 Results of scanning with the mirror scannerconstruction, it was possible to prevent beam aberration and to shorten
the switching time. The construction can also contribute to lowering
signal leakage if the switching paths are arranged skillfully.
4. Micro-lens Two-Dimensional Laser Scanner
Fig.4 shows an optical transmission scanner employing the XY
movement of a micro lens. Unlike the mirror type scanner, the lensmovement and scanning angle of the light are linear. Further, the lenscan be maintained at a desirable position. Four polysilicon scratch drive
actuators are employed to drive the lens. The lens position (scanning
angle) is controlled through the counting of voltage pulses.

Lens, diffraction grating, filter

Fig.1 Concept of micro-mechanical smart pixels

3. Two-Dimensional Torsion Mirror Laser Scanner with
Electrostatic Actuators
Fig.2 shows an electrostatic torsion mirror device serving as a twodimensional optical scanner, using a micro mirror to reflect light. The
transter function of this device has large nonlinearity and crosstalk.
Hence, complex feedback control would be needed to achieve precise
positioning control in a device for modifying the optical path of smart
pixels, for example. In order to simplify transient control for switching,
we developed a reliable open-loop control method and an analyticalmodel. The drive voltages are determined based on this model. Fig.3
shows the reflected beams projected on a grid pattern grating. With thisOuter Frame

Torsin Bar (f-scan)

Y

V1

V2

100~200 V, 30~340 Hz

5. Conclusion
As described above, we developed two types of trial opticalscanners: a reflection type and transmission type, evaluated theirperformances, and built an analytical model. We were able to gather
much data on process yields inherent in surface machined devices,
failure modes during operations, and analytical methods. We would liketo further reduce the size of these devices and attempt to integrate themwith an actual control drive circuit.

fXu
Mirrorf

Torsin Bar (u-scan)

400µm

V3

Pulse CounterFig.4 Two-Dimensional micro-lens laser scanner

Zu

Inner Frame

500µm

Lock Mechanism
V4

Acknowledgments
The results of this study were obtained through joint research
conducted during FY 1999 and 2000 in the laboratory of Prof. Ming C.
Wu of UCLA's Electrical Engineering Department.

Scratch Drive Actuators

Fig.2 Two-dimensional torsion mirror laser scanner10Experimental Study on Fluid Flow and Heat Transfer inside
Microchannels Utilizing Micromachining Technology
Shigefumi Nishio, Professor,
Kiyoshi Takano, Research Associate,
2nd Division, Institute of Industrial Science, The University of Tokyo
1. Introduction
As channels are being manufactured with increasingly smaller innerdiameters, we are beginning to see the emergence of a peculiar
thermohydrodynamic effect. This suggests that estimations on thenormal scale can produce major errors, making it impossible to estimate
the flow and heat transfer characteristics of a fluid with precision. The
present study is aimed at determining the channel diameters at which
specific thermal and flow phenomena occur and clarifying thecharacteristics of such phenomena. In general, heat transfer increases
with decreases in the equivalent diameter. However, we hypothesizedthat heat transfer may reach a maximum value at a certain diameter. It
is conceivable that the results of this study will provide valuable
information for many fields with broad applications.
2. Experiment Methods and Equipment
Fig.1 shows an overall view of the equipment used in the experiment.
The equipment comprises a (1) fluid supply system (micro-pump, buffertank, filter, pressure gauge of diaphragm type, and flowmeter), a (2) fluid
heating and vacuum insulation system (constant temperature bath andvacuum pump), and a (3) cooling-fluid supply system (constanttemperature bath, pump or air blower, and magnetic flowmeter).

u

r
i

r
y

r
t
e

q Test Liquid Inlet
w Hot Water Circulatione Vacuum Chamberr K-Type Thermocoupleqew

t Cooling Chambery Micro-channelu Window
i Test Liquid Outlet

Fig.2 Detailed construction of the test section

The Nusselt number Nu i in the present experiment was within a range ofabout 0.7-1.0. This value is clearly smaller than the fixed value 4.36 forlaminar flow at a constant heat flux on the normal scale and is 1.7-3 times
higher than the results of Choi, et al. Further, the Nusselt number Nui wasclearly shown to be dependent on the Reynolds number Re, as the Nusselt
number Nui decreased along with decreases in the Reynolds number.
4. Conclusion
The following conclusions were made after analyzing measurementsof the coefficient of friction and the average Nusselt number Nu i in a
microchannel having an inner diameter of 52.9µm and a length of 30mm.
(1) The average Nusselt number exhibited heat transfer characteristics
thought to be inherent in microchannels, including a value lower than
the normal scale and decreases dependent on the Reynolds number.
(2) From the above results, a diameter near the lower limit that exhibits
heat transfer characteristics on the normal scale is optimal for thedesign of heat exchange devices. However, this issue needs to be
examined further in the future.

Fig.1 Overview of equipment used in the experimentFig.2 shows a detailed construction of the test section in theexperimental equipment. Since the test section should be designed to
drastically reduce heat loss around the microchannel, all parts except thefluid heating unit at the inlet are made of an acrylic resin. Fluid is
introduced through the test liquid inlet (1), where it is heated to aprescribed temperature (50˚C) by circulated hot water (2).
Subsequently, the fluid passes through a vacuum chamber (3) and isintroduced into the microchannel (6). During the experiment,
measurements are taken of the fluid temperature at the inlet and outlet ofthe microchannel, flow rate of the fluid, temperature and flow rate of thecooling water, and pressure of the fluid at the inlet to the microchannel.
3. Results
As for the friction factor on the normal scale, f, the f-Re value is fixed at
64. In the present experiment, however, the f-Re value was approximately
twice that on the normal scale. While this is considerably higher thanresults of microchannel measurements reported thus far, the reason for thishigh value has not been identified at this stage. Fig.3 shows themeasurements taken of the average Nusselt number Nu i in the channel.

Fig.3 Measurements of the average Nusselt number

11Low Noise Feedback Interferometryfor Micromachine Servo Actuators
T.H.Barnes
Professor,
Physics Department, University of Auckland, New Zealand
1. Introduction
In this project we have developed the new technique of feedback
interferometry for micro machine applications where displacement
measurements to an accuracy of a few nm are desirable. Feedback
interferometry has the potential to measure phase rapidly, with highaccuracy, using simple optical systems, but its performance limits havenot been know until now.
We have for the first time determined feedback interferometer
accuracy, the conditions under which they are stable, and their noise
performance. We tested our theory in the laboratory using a prototype
high-precision feedback interferometer. It was capable of measuring
movements with a repeatability of l/80, and linearity better than l/100.
2. Principles
Fig.1 shows a generic feedback interferometer. The output intensityof the interferometer is used to control the phase in one arm of a two
beam interferometer. The instrument measures the interferometer
phase fi which in a micromachine system might - for example - arise
from movement of the other interferometer mirror. By solving the
feedback interferometer equation:
I o/ B=1+cos ( f i +GI o/ B) .............(1)we find that the interferometer output intensity Io varies linearlywith phase. Interferometer phase can then be determined directly fromthe output intensity (Fig.2). The system can track accurately over
several wavelengths.

3. Experiments and Results
Fig.3 shows our prototype interferometer to compare the accuracyof feedback interferometry with conventional phase-stepping andheterodyne techniques.
Feedback is applied via mirror M2, with mirror M1 moved by piezo
actuator to vary interferometer phase.
Fig.4 shows the interferometer accuracy. The phase from feedback
interferometery is linearly related to that phase stepping withrepeatability of l/80.

Fig.3 Experimental Interferometer System

Fig.1 Feedback InterferometerFig.4 Phase Measurement Characteristic

4. Conclusion
We have shown that feedback interferometry is a promising
candidate for application to micromachines. It is capable of highaccuracy and linearity with a simple opto-electronic system that can bemade to operate at high speed.

Fig.2 Feedback Fringe Profile

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