Fluorescence‑Based Calibration Model for In‑Situ Measurement of Micro‑scaled Lubricant Thickness Distribution at Indentation Interface

This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence signals.The interfacial conditions between the tool and the workpiece in mechanical machining are important for understanding these phenomena and mechanisms.In this study,indentation tests with transparent tools were used to observe interfaces;however,it was challenging to obtain the signal from a thin fluorescent liquid film on smooth and steeply inclined surfaces.Therefore,fluorescence-based measurement,such as laser-induced fluorescence,was employed.To measure the absolute thickness of the thin fluorescent film,calibration of the measurement system is necessary.Therefore,a theoretical model was proposed considering the multiple reflections of excitation light and fluorescence at the inclined surface between the indenter and workpiece.By measuring the profile of the surface topography of the indented workpiece and comparing the results with those measured by a surface profiler,the validity of the proposed calibration method and the performance of this measurement system were demonstrated.The measured surface profiles,including scratches of 2–4μm,were in good agreement,demonstrating the validity of the proposed method.

In-Process Diameter Measurement Technique for Micro-Optical Fiber with Standing Wave Illumination

In this paper,we propose an in-process measurement method of the diameter of micro-optical fiber such as a tapered optical fiber.The proposed technique is based on analyzing optically scattered light generated by standing wave illumination.The proposed method is significant in that it requires an only limited measurement range and does not require a high dynamic range sensor.These properties are suitable for in-process measurement.This experiment verified that the proposed method could measure a fiber diameter as stable as±0.01μm under an air turbulence environment.As a result of comparing the measured diameter distribution with those by scanning electron microscopy,it was confirmed that the proposed method has a measurement accuracy better than several hundred nanometers.

Flexible Evanescent Wave Interference Lithography System for Sub-half-Wavelength Complex Relief Structures Fabrication

Surface microstructures impart various useful properties to objects,for example,improving optical characteristics,wettability,and sliding properties.It is well known that biomimicking relief structures are effective in making such properties arise and have been studied to be applied to various devices.Furthermore,they are expected to be utilized not only for improving a particular property but also for adding more complex functions on a device's urface by fabricating different multi-functional structures on a single surface in the future.However,to begin with,artificially fabricating such biomimicking special functional relief is difficult.One typical feature of biomimicking surfaces is the dual-scale structure,the smaller one of which is less than 200 nm.Moreover,in the case of realizing the more complex devices,it is necessary to fabricate various forms as changing process conditions dynamically.In this study,we proposed and developed a flexible evanescent wave interference lithography system as a novel fabrication method,which allows us to realize the fabrication of sub-half-wavelength complex relief structures.Firstly,we theoretically analyzed the fundamental behavior of the fabricated structure and found that the proposed concept has the potential to realize one of the target complex structures.Secondly,we developed the proposed system with high process flexibility,in which the number of beams,the azimuth angles,and the polarization can be simply manipulated.Finally,we validated the concept of the designed system by some experiments,where we fabricated dual-scale structures with 840-nm and 190-nm fringe patterns simultaneously.

Micro-scale Additive Manufacturing Using the Optical Potential Generated by a Bessel Beam

In this study,we proposed a novel micro-scale additive manufacturing method based on the optical potential formed by a Bessel beam.The proposed technique is expected to show no deterioration in manufacturing resolution due to heat genera-tion,to be applicable to various materials,and to be able to be performed in an air environment.The basic principle of the proposed method involves accumulating and stacking particles dispersed in air by using optical radiation pressure.In this paper,the trajectory of the accumulated particles was numerically estimated and experimentally observed.The numerical and experimental results agreed well;specfially,the back ground flow carried the particles to the optical axis of the Bessel beam,and then the particles were localized at the bottom of the optical potential valley on the substrate.Finally,a pillar structure was fabricated with polystyrene particles having a diameter of 1 um,which indicated that the proposed technique was promising for practical applications.

Foreword to the Special Issue on Micro-and Nano-Metrology in Japan(II)

Micro-and nano-metrology occupies an important position in modern production engineering where higher-precision machining is required.A visualization of the process is indispensable for the creation of new technologies in state-of-the-art manufacturing that deals with the geometrical quantity at the micrometers/nanometer level.Precision micro-and nano-metrology is thus becoming increasingly important as the platform of various manufacturing technologies,as well as strategic tools for responding to rapidly changing fabrication techniques in many scientific and industrial fields.

Foreword to the Special Issue on Micro- and Nano-Metrology in Japan(I)

Micro-and nano-metrology occupies an important position in modern production engineering where higher-precision machining is required.A visualization of the process is indispensable for the creation of new technologies in stateof-the-art manufacturing that deals with the geometrical quantity in micrometers/nanometers.Precision micro-and nano-metrology is thus becoming more and more important as the platform of various manufacturing technologies,as well as strategic tools for responding to rapidly changing fabrication techniques in many scientific and industrial fields.