Fiber-optic tactile microsensor for detecting the position of the tip of a fiberscope

A tactile microsensor employing optical fibers has been developed and evaluated. The sensor is used for touch sensing to detect the position of the tip of a fiberscope inside a small tubule, such as a blood vessel. The sensor consists of bosses as feelers, which are split sections of the end of a polyurethane tube, a metal diaphragm as a mirror and optical fibers transmit light. The sensors are fabricated using silicon micromachining, such as anisotropic etching and excimer laser etching. The sensing principle is based on the detection of changes in optical reflective intensity from a diaphragm located between a boss and an optical fiber. The width and height of the boss are both 200 /spl mu/m. For the transmitting source and signal light, a multimode optical fiber 50/125 /spl mu/m (core/clad) in diameter is used. The results show that tactility measurements can be made easily and safely in blood vessels. This paper describes the structure, fabrication processes, and performance of the sensor. We also propose micromeasuring systems combined with the tactile sensor and a fiberscope of contact type.