This paper presents a system for measuring 3D micro-structures that uses an optical fiber probe equipped with a piezo element that causes the probe to vibrate. The optical fiber probe consists of a stylus shaft with a diameter of 3 µm and a glass ball with a diameter of 5 µm attached to the tip. The stylus is vibrated in a circular motion in a single plane. The vibrator mechanism is introduced to prevent adhesion of the stylus tip to the surface being measured. This adhesion, which adversely affects the accuracy and time of the measurement, is caused by intermolecular, electrostatic, and liquid bridge forces. The measuring principle involves monitoring the vibrational amplitude of the stylus shaft that is required to prevent the adhesion of the stylus tip to the surface being measured, this amplitude being measured optically. In our previous report (Murakami et al 2012 Key Eng. Mater. 523–524 907–12), we found that the stylus shaft actually moves in an elliptical motion when it is set to describe a circular motion in the X-Y plane. Therefore, when a measurement is taken, it is necessary to adjust the motion of the piezoelectric tube to compensate for the difference between the diameter of the perfect circle and the actual elliptical motion of the stylus shaft displacement. In this study, the stylus characteristics were examined and the motion of the stylus shaft was then corrected to attain the desired circular motion. Next, the expansion of the measuring area by using a line laser was investigated. Finally, an experiment involving the measurement of a micro-hole was performed to demonstrate the practicality of the vibrating fiber probe. As a result, it was shown that the displacement between the diameter of the perfect circle and the actual elliptical motion of the stylus tip was about 0.034 µm after compensation. In addition, it was confirmed that the measurement area can be expanded by using an optical slit, but the standard deviation of the repeatability of the point measurement with the slit decreases to about half of that without the slit. In addition, the practicality of this system was confirmed by measuring the shape of a 100 µm diameter micro-hole.

This paper presents a system for measuring micro holes that makes use of an optical fiber probe. The optical fiber probe is deflected when it comes into contact with a hole surface, and this deflection is measured optically. For this research, the optical fiber probe is fabricated by using an acid etch technique and its characteristics in the process of displacement detection are described. The effects of surface force are then evaluated. The diameter of the optical fiber probe sphere at the tip of the probe is calibrated by using a 1mm gage block, and the effect of the probe sphere diameter is compensated for measurement of the roughness standard specimen. As a result, it is confirmed that the accuracy after compensation of the roughness standard specimen as measured by the measuring system corresponds well to that of the surface roughness tester in both shape and value, demonstrating the utility of this means of calibration.

We investigated the effects of specific light wavelengths from light-emitting diodes (LEDs) on the growth of the dinoflagellate Heterocapsa circularisquama, which kills bivalves, and the diatom Skeletonema costatum, which is an important food source for bivalves. Growth of H. circularisquama was obviously inhibited at 590 nm and a photon flux density less than 75 mmol quanta/m 2 /s. However, growth of S. costatum was not suppressed by irradiance from any LEDs tested from near-ultraviolet to near-infrared wavelengths at 75 mmol quanta/m 2 /s. The growth rate of H. circularisquama in an experimental treatment group with irradiance provided by both cool-white fluorescent lamps (12:12 h L : D cycle) and a 590-nm LED (continuous irradiance) was 0.43/day. In the control group with irradiance provided only by cool-white fluorescent lamps (12:12 h L : D cycle), the growth rate was 0.63/day, indicating that growth of H. circularisquama was suppressed by 590 nm (less than 75 mmol quanta/m 2 /s) irradiance from the LED and the continuous irradiance. The use of 590-nm LEDs in bivalve culture at irradiance levels less than 75 mmol quanta/m 2 /s might encourage the growth of the useful diatom S. costatum without stimulating growth of the harmful dinoflagellate H. circularisquama.

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The precise measurement of microstructures and other micron-sized materials has garnered considerable interest in recent years. However, a limited measurement region and the unavailability of miniaturized probes are the major issues in the realization of such systems. In this study, we have presented a system for microstructures based on a small-diameter optical fiber probe. In the improved measurement system, the prism was installed near the stylus shaft to expand the measurable region and depth. This means that there is no limitation on the width of the measurement object. The standard deviation of the repeatability of the point measurement in the X-, Y- and Z-directions was 31, 38 and 19 nm, respectively. A pin gauge with a diameter of 100 µm was measured ten times for assessing the repeatability of measurements in the X- and Y-directions. The standard deviation of the diameter in these measurements was 25 nm. A step height standard with a calibrated height of 189.6 nm was measured ten times for assessing the repeatability of measurement in the Z-direction. The average height in these measurements was obtained as 200.2 nm with an expanded uncertainty of 49.3 nm (coverage factor k = 2). We confirmed that this system enabled accurate measurement in the X-, Y- and Z-directions.