Shigeki Saito

Tokyo Institute of Technology | TITech · Department of Transdisciplinary Science and Engineering

Recently, techniques of arranging micrometer-sized objects under a scanning electron microscope (SEM) are required to construct micro-devices such as quantum optics devices. Since micro-objects tend to adhere to other objects mainly by electrostatic force, it is possible to pick them easily with a needle-tip instead of grasping by a gripper. Howeve...

A multi-beam structure using Ti-Ni wire to grip rough surfaces and control detachment was manufactured. The grip-and-release mechanism of the structure was investigated. The experimental results were analyzed with a model assuming beam theory and using a fracture criterion at the adhered interface. The fracture criterion of the adhesion interface i...

Adhesion between the lower surface of an elastic beam and the flat surface of a substrate during a loading-unloading cycle is experimentally investigated. In the presence of adhesion, it has been theoretically explained that the force curve for the loading and the unloading coincide with each other because reversible thermodynamic work of adhesion,...

An electrostatic chuck (ESC) is a device used to clamp and transport flat-surfaced objects such as thin semiconductor wafers. Working by the principle of electrostatic force, its functionality is limited in handling objects with rough surfaces, as the attractive forces at work are significantly reduced. To improve this weak point, by employing 70 μ...

An electrostatic chuck (ESC) is a type of reversible dry adhesive which clamps objects by means of electrostatic force. Currently an ESC is used only for objects having flat surfaces because the attractive force is reduced for rough surfaces. An ESC that can handle objects with rough surfaces will expand its applications to MEMS (micro electro mech...

This research proposes a virtual environment (VE) for co-designing in early childhood education and care settings using a social VR platform with 3D-scanned childcare rooms. Co-design workshops were analyzed focusing on perceived presence and experience and workshop outcomes. The results indicate a high level of presence in the VE, with unique adva...

This paper aims to identify gaps between the reflection frameworks and students’ practice. Through a systematic literature review (PRISMA) and a qualitative survey of students, 12 reflection frameworks were reviewed, and the 13 challenges students faced at design projects in two design schools were identified. The results indicate three gaps betwee...

This study proposes a diary method enabled with IoT sensors for user research in design. It addresses the limitations of diary methods by incorporating sensor data to trigger user self-reports. The focus is on how sensor data influences self-reports and designers' perceptions. Results show that sensor-enabled diaries offer more diverse content and...

The demand for the manipulation of flexible film-like objects and those with non-planar surfaces, which cannot be handled using current technologies, has increased considerably. A bipolar electrostatic chuck (ESC) is a device that clamps target objects using a uniform electrostatic force. Traditional ESCs cannot satisfy these demands because of the...

This study provides a systematic literature review, investigating current uses and application of behavioural data in services design process. The results show a predominance of data usage either on product design process by professional designers or on personal reflection by service users, and more importantly, there is a large gap in what designe...

We designed a data-driven workshop program to encourage ownership to social challenges. Three different social challenges were the themes of the workshops; “future food,” “future community child-rearing,” and “future work style”. In each workshop, both statistical and video data were provided. Participants were asked to answer questionnaires before...

In designing products and services that improve the quality of childcare, it is necessary for designers to empathize deeply with people involved in childcare (i.e., day care teachers) to understand context-dependent know-how. For that purpose, co-design, a collaborative design activity involving designers and non-designers, is essential. To conduct...

To solve social issues, it is not enough for a single entity to act; it is necessary to recognize the issues as our affairs and to have a “sense of ownership” and act toward their solution. The concept of “sense of ownership” or “psychological ownership” is used in the fields of educational psychology and business administration to encourage each i...

We propose VisRef, a video-based reflective support system incorporating a fixed-point camera and a smartwatch, and investigate its application for improved retrospection in childcare fields. When a childcare worker wearing a smartwatch encounters a situation he or she hopes to reflect upon later, the worker can press a button on the smartwatch to...

In project-based learning (PBL), a powerful pedological framework in design education, groups of students develop prototypes toward a given design topic. The groups consist of members of different disciplines to stimulate the creativity of design outcomes. However, the impact of disciplinary diversity on outcomes has not been sufficiently investiga...

Electrohydrodynamic (EHD) drying is an emerging drying technology that is based primarily on the phenomenon of ionic discharge between two electrodes. The aim of this study was to experimentally investigate the energy efficiency of the EHD drying based on the corona discharge current. Moreover, we aimed to compare the energy efficiency of the EHD d...

This paper describes the development of bipolar electrostatic chucks with a compliant beam-array structure using abrasive water jet technology. The chucks are cut out from 3D-printed composite-laminated plates and the attractive forces that they generate are measured. Their performance is compared with electrostatic chucks (ESCs) made using a 3D-pr...

This technical paper demonstrates the influence of the probe-tip surface smoothness of a bipolar electrostatic chuck (ESC) on electrostatic force. ESC, which has a silicon-based beam-array microstructure, aims to pick and place a dielectric object with a curved surface owing to the compliance of its elastically deformable beams. The ESC was fabrica...

This study aims to investigate the good way to generate insight through empathy with users. The fifteen experiment participants drew thinking processes of understanding users and defining insight statements while generating insight statements based on a given interview transcript. The thinking processes were assessed by qualitative coding, and the...

This study aims at developing a new user research method that uses IoT sensors embedded at users' homes to enable users to recall their memories. The proposed method was evaluated by experiments where four participants individually created user journey maps with quantity data that was collected for seven days. The results showed that IoT sensor dat...

This study proposes and verifies bipolar electrostatic grippers stacking 3D-printed-layered modules consisting of arrays of elastically deformable bipolar beams. The influence of the mechanical compliance of grippers on the attractive force that it generates is clarified by comparing two types of modules having either high or low mechanical complia...

It is a key competence of companies to develop innovative products. Those products are developed by a team of people from diversified backgrounds. However, merely forming a multidisciplinary team does not directly link to a higher degree of creativity of outcome. The degree of creativity of outcome is largely contributed by early phase of design pr...

Based on a theory of sessile drop in gravity, a method to evaluate surface tension is proposed, and its applicability is discussed. All of parameters are theoretically normalized. Although it is impossible to obtain analytic solution of the surface profile of the sessile drop, it is possible in an extreme condition of large volume. A universal param...

As a device for pasting film objects on curved surfaces, this paper proposed a device, composed of a shape adaptable mechanism and an elastic electrostatic chuck, which is operated by two robot arms. As the shape adaptable mechanism generating a wide range of variable curvature radii, a single-DOF scissor mechanism with an elastic element was prese...

There has been much research offering theoretical explanations of rolling behavior considering the effect of adhesion, which is essential when the object is small. However, there has been a shortage of experimental verifications because objects are too small to manipulate and observe directly. This study measured the moment and observed the contact...

A 3D-printed-layered structure for forming the compliant bipolar electrostatic gripper is proposed. A prototype gripper module, which consists of an array of elastically deformable bipolar micro-probes, is fabricated using a conventional 3D printer. Experiments are conducted to examine the attractive force and the pick-and-place performance of the...

This paper proposes a contact model between a rigid sphere and an elastic plane covered with a thin liquid film. The elastic contact is determined by Johnson–Kendall–Roberts theory, which deals with the energy equilibrium of elastic and interfacial energies. In elastic contact under presence of thin liquid film, the energy needed to separate the tw...

Based on a theory of sessile drop in gravity, a method to evaluate surface tension is proposed, and its applicability is discussed. All of parameters are theoretically normalized. Although it is impossible to obtain analytic solution of the surface profile of the sessile drop, it is possible in an extreme condition of large volume. A universal para...

This paper proposes an analytical model for the Boussinesq problem between a tilted rigid punch and an elastic half space to enable the analysis of elastic deformations inside and outside a contact area. Inside the contact area, two types of pressure distributions are applied: one generates a flat elastic deformation, and the other produces a tilte...

Various tools for participatory design approach have been developed to support users to engage design process. Doll scenario is proposed as a generative tool for letting participants make and enact scenarios. However, suitable context to practice doll scenario is unclear in comparison with other tools using scenario. Therefore, our overall objectiv...

Co-design approaches invite users in the early phases of design process for designing new products or services, which helps collecting users’ Kansei data. As users are not formally trained as designer, tools and techniques have been proposed to help users to be creative in co-design. However, hierarchical structure in design teams has negative impa...

In this paper, we propose a successful fabrication method for a bipolar electrostatic chuck (ESC) device with a beam-array assembly, in order to achieve a fairly flat surface on the beam's tip. A fabricated bipolar ESC device is expected to clamp a curved dielectric object due to its elastically-deformable beams, which are compliant with an object'...

Relative humidity dependence on electrostatic pick-and-place operation is investigated to improve the reliability of micro-manipulation. The manipulation system consists of three elements: a conductive probe as a manipulator, a conductive plate as a substrate, and a dielectric particle as the target object for manipulation. To pick up/place the par...

In this study, we fabricated a bipolar electrostatic chuck having hairy silicon-based microstructure with smooth contact surface by lithography technology. Using DRIE, we succeeded in creating electrostatic chuck structure with high surface accuracy. We deserved the surface of tips observation with FE-SEM , and evaluated the performance by force cu...

This article reports the case of Engineering Design Project since 2015 at Tokyo Institute of Technology as a new challenge of long-term Project-Based-Learning (PBL) for radical collaboration among people having different expertise and/or backgrounds via “Design Thinking” approach. Regarding the Engineering Design Project, the author describes the d...

This study proposes a method of estimating the thermodynamic work of adhesion using the spherical contact between a glass lens and a polydimethylsiloxane (PDMS) block. An equivalent stiffness of the measurement system is determined prior to the experimental measurements. Parameters such as force, contact radius, and displacement are measured during...

Adhesion hysteresis was investigated with the energy dissipation in the contact experiments between a spherical glass lens and a polydimethylsiloxane (PDMS) block. The experiments were conducted under step-by-step loading–unloading for the spontaneous energy dissipation. The force, contact radius, and displacement were measured simultaneously and t...

Understanding of change of a contact area due to a passage of current is significance for design of electric contacts of MEMS devices. In this paper, we investigate the change of contact area experimentally. In the whole experimental process, resistance and force generated around the contact area are measured. Those values are used for the estimati...

Understanding the rolling behavior of a micro-object is essential to establish the techniques of micro-manipulation and micro-assembly by mechanical means. Using a combined theoretical/computational approach, we studied the critical conditions of rolling resistance of an elastic cylindrical micro-object in adhesional contact with a rigid surface. C...

By clarifying the effect of surface conductivity and adhesivity on the electrostatic manipulation condition, a dielectric particle made of any material can be manipulated with surface conductivity. The manipulation system consists of three elements: a conductive probe as a manipulator, a conductive plate as a substrate, and a dielectric particle as...

A compliant electrostatic gripper with bipolar voltage polarity for a pick-and-place manipulation is presented. The compliance, realized by the introduction of an array of micropillars which act as the electrode, extends the application of electrostatic-based gripper to manipulating fragile, rough-surfaced dielectric objects at macro scale. A proto...

Geckos and some insects can easily adhere to and detach from surfaces with micro/nanoscale hair structures on their foot, called setae and spatulas. Here, a model is developed to describe the detachment of the seta. In this model, the seta is assumed to be a beam whose tip adheres to a surface. When normal and tangential forces are applied to the r...

A model with surface conductivity and adhesional force is proposed to investigate the mechanism for electrostatic micro manipulation of a dielectric object using a single probe. The manipulation system consists of three elements: a conductive probe as a manipulator, a conductive plate as a substrate, and a dielectric particle as the target object f...

The change in temperature distribution due to constriction of an electric current through a contact area is analytically and numerically investigated. The potential distribution, current density distribution and heat density distribution inside the body are analytically obtained. The heat density has the singular point at the periphery of the conta...

The density distribution of point-contact current is theoretically investigated. Finite current is introduced to a semi-infinite body from the outside. The following assumptions are made: the contact area is circular, magnetic effects are ignored, the contact area is equipotential, the potential equals zero at an infinite distance from the contact...

The recent papers Saito et al 2013 Smart Mater. Struct. 22 015019 and Dhelika et al 2013 Smart Mater. Struct. 22 095010 described studies of an electrostatic chuck that mimics the structure of gecko-like toes. Earlier work published by the authors and other researchers is cited to further illustrate the origin and motivation of the research.

A theory of adhesion between an elastic beam and a rigid body is proposed using linear beam theory. Normalized force between the elastic beam and the rigid body considering adhesion of the side surface of the elastic beam is investigated theoretically. Adhesion of an elastic beam is important to analyze gecko adhesion, and peeling mechanism of an a...

Adhesion contact between a rigid sphere and an elastic body with a flat surface is experimentally investigated. The time dependence of the contact radius on loading and unloading is observed. Based on the total energy of the JKR (Johnson, Kendall, and Roberts) contact, the hysteresis of the contact radius in loading-unloading trajectories is discus...

Reversible adhesive joining that involves altering the elastic modulus of an elastic body is proposed by considering adhesion between a semi-infinite elastic body and a rigid body that has a slightly wavy surface with defects. Separation stress of adhered surfaces is theoretically expressed as a function of the elastic modulus. However, the express...

Recently, micromanipulation techniques have been in high demand. A technique to deposit a metal microparticle onto a metal substrate by using a single metal probe has been proposed as one of the techniques. A solder particle with a diameter of 20–30 µm, initially adhering to the probe tip, is detached and deposited onto a substrate. The success rat...

We propose a new method to simulate the interface diffusion in the solid-state bonding-process. This method is more significant under the condition of low pressure and low temperature. It is available for the bonding of two bodies which consist of the atoms of the same kind and have slight surface roughness. In a conventional method, the elastic de...

Analyzing the rolling behavior of micro-object is necessary for the realization of the micro-manipulation technique by mechanical-method. Thus in this paper, we obtain the rolling resistance of an isotropic elastic cylindrical micro-object in adhesive contact to a rigid surface. In order to estimate the rolling resistance, we assume this adhesive c...

This paper presents a scheme of micromanipulation with a liquid bridge and an analysis of the capillary forces involved. The following procedure is considered in this article: (a) PICK UP: a probe, with liquid in the tip, approaches the target object. (b) A liquid bridge forms between the object and the tip of the probe. (c) The object is picked up...

Recently, micromanipulation techniques for handling a conductive microparticle have been in demand. Electrostatic micromanipulation with a single probe is a promising technique for such manipulation. While the feasibility of the technique has been proved experimentally, the success rate of manipulation was 25%, and further improvements are required...

In this study, we have developed the technique of electrostatic manipulation of a dielectric microparticle by a single probe. The manipulation system consists of three objects: a conductive probe as a manipulating tool, a conductive plate as a substrate, and a dielectric particle that dubs as a microparticle. In manipulating 60 μ m in diameter part...

A technique using capillary force as a method for self-alignment of micro particle is recently remarkable. This paper has proposed a technique to distribute desired liquid pattern for such method using phase transition of vapor on functional surface. A glass plate with asperity made by engraving was fabricated as functional surface. Then that plate...

Adhesion between a semi-infinite elastic body and a rigid surface with a sinusoidal roughness is solved. The solution is exactly same as that of K. L. Johnson (Int. J. Solids Structures, v.32, p.423 (1995)), although the different method is used for the derivation. Based on the solution, possibility of reversible joining process is considered. Cond...

This note reports on an experimental demonstration of non-impact deposition for electrostatic micromanipulation of a conductive particle by a single probe. The experimental system consists of a probe, a 30-micrometers-in-diameter particle, and a substrate plate. The particle, initially adhering to the probe tip, is detached and deposited onto the s...

This study reports the possibility of electrostatic micromanipulation of a conductive/dielectric particle using a single probe. The manipulation system consists of three objects: a conductive probe as a manipulating tool, a conductive plate as a substrate, and a conductive/dielectric particle that dubs as a micro-particle. For a conductive particle...

In order to expand the applicability of modified embedded atom methods (MEAMs) from bulk to non-bulk systems, a dimer reference MEAM (DR-MEAM) is proposed. In this method, a diatomic structure is selected as the reference structure and the parameters for Cu are determined from the properties of the equilibrium bulk structure and some clusters, in o...

This paper deals with the expansion of capillary force range with a concave probetip for micromanipulation. From numerical simulation,we found the following; the concave probe-tip can generate a much larger capillary than a flat one, provided it is designed to fit the convex surface of the object; the more wettable a material is, the greater capill...

Experimental measurements on a cm-scale replica structure of a gecko foot-hair where magnets are used in place of (the usual) van der Waals force are reported. We conduct naked-eye experiments and investigate the mechanical properties of such hair structure and shapes that constitute it. Links between shapes and mechanical properties (functions) us...

In this paper, an approach to condense micro droplet with aimed volume and to maintain its volume is shown. The approach is performed experimentally by means of controlled temperature sequence. Peltiert element was used to control the temperature of copper surface. Pico litter ordered droplet was observed and its volume was estimated by video image...

Geckos generate the necessary adhesion force through their foot hair. The direction of the gecko's foot hair is not perpendicular to its finger surface, giving compliance to the hair. The effect of this compliance on the adhesion force is analysed and expressed theoretically in terms of contact mechanics. We conclude that the compliance of the foot...

We introduce a climbing system, inspired by gecko foot that uses magnets in place of Van der Waals interaction. This is possible because both forces, except for a scale factor, have similar force-curves. Taking advantage of this fact, we manufactured a hand-size "magnetic" version of a gecko-foot. This allowed us to conduct naked-eye experiments. A...

We introduce a climbing system, inspired by gecko foot that uses Electrostatic Chuck (ESC) in place of Van der Waals interaction. Electrostatic chucks are currently used in wafer foundries to pick-up and move delicate thin semiconductor wafers. The properties of ESC make it an interesting adhesion force for wall mobility applications. However the g...

Modified Embedded Atom Method '92 (MEAM92) developed by Baskes is the most popular among researchers using Embedded Atom Method series, because MEAM92 has high reliability for bulk system, and parameters are determined consistently. However, the applicability of this method to non-bulk systems, such as surface, is still uncertain. In such backgroun...

This letter describes the measurement of capillary force with a concave probe-tip for micromanipulation. Using an electric balance, we measure the capillary force for a given gap distance between a spherical object and a concave surface coaxially fabricated on a cylinder. We used three different materials (glass, stainless steel, and polytetrafluor...

The micromanipulation technique in a scanning electron microscope (SEM) has been attracting interest as a technique to produce microstructures such as three-dimensional photonic crystals or advanced high-density electronic circuits. However, it is difficult to fabricate a large-scale structure or to conduct a systematic experiment using numbers of...

As the size of object diminishes, the effect of adhesional forces grows stronger for micro-manipulation and so. The capillary force generated by a liquid bridge can be greater than both the capillary force generated by another bridge and the adhesional force because the capillary force can be controlled by regulation of the liquid volume. We propos...

In the micrometer range, it is difficult to manipulate objects with a hand or gripper because the effects of the adhesional forces induced by solid-solid contact cannot be neglected at such scales. However, if capillary phenomena could be controlled, we could apply it to counteract the effects of the adhesional forces since capillary force is known...

This letter describes a calculation of a voltage sequence to obtain kinetic control of a particle for nonimpact electrostatic micromanipulation. The system consists of conductive objects: A manipulation probe, a spherical particle, and a substrate plate. The particle, initially adhering to the probe tip, is detached by an applied voltage. The elect...