Tetsuma Sakurai

A hybrid sensor for the measurement of a wide range of longitudinal surface displacement based on laser reflection and scattering

A hybrid sensor for measuring longitudinal surface displacement including surface undulation and surface roughness over a wide range from nm to a few hundred µm has been developed. Two main sensors are incorporated in a single body, i.e., it is a hybrid system, with one sensor based on laser reflection for nm-scale measurement, while the other is based on imaging the irradiated portion for µm-scale measurement. A preliminary experiment using this hybrid sensor showed that the sensor for measuring surface undulation has a longitudinal resolution of 1 nm and a measurement frequency of 24 Hz, and that the sensor for measuring surface roughness has a longitudinal resolution of 2 µm, a measurement range of ±300 µm and a measurement frequency of a few hundred Hz. This hybrid sensor is relatively compact and its cost/performance ratio allows its practical use.

Non-metallic VEP stimulator without interference in CT scanning for neurosurgical operation

Non-metallic flash-type stimulators for monitoring visual evoked potential, named as the Fiber-Eyes, are proposed. Conventional VEP stimulators are comprised of LEDs and the print circuits, i.e. metallic materials, inside the stimulator. Proposed Fiber-Eyes are made from plastic optical fibers, silicone rubber, and external light source. Thus the Fiber-Eyes can be used together with CT scanning without interference in the image due to not use of the metallic parts during neurosurgical operations. They do not also radiate heat because the flash light for stimulus is supplied through the fibers, and thus it can avoid desiccation of the bulbar conjunctiva of patient in the operation.