PRESSURE SENSOR, PRESSURE VIBRATION DETECTION APPARATUS USING THE SENSOR, AND PULSE WAVE DETECTION APPARATUS

摘要

This invention aims at providing a pressure sensor which can be easily made compact and can detect a pulse wave. The pressure sensor (10) comprises pressure-sensitive devices S1 to S4 and a flexible rubber (1). Each of pressure detection positions Q1 to Q4 of each of pressure-sensitive devices S1 to S4 exists on the bottom surface L of the protrusive flexible rubber (1) and on x or y axis which is equidistantly spaced apart by a distance a &cir& _ from the origin. When the flexible rubber (1) is pressed to a portion near an artery, vibration occurs on the exposed surface of the flexible rubber (1) due to blood fluctuation by the artery, that is, by the pulse wave, and this vibration propagates across the elastic rubber (1) as an elastic wave and is detected as a pressure wave by the pressure-sensitive devices S1 to S4. Since the magnitude of the pressure wave is inversely proportional to the square of the propagation distance of the elastic wave inside the flexible rubber (1), the coordinates formed by projecting the pressure wave generation point on the bottom surface L can be calculated from the voltages V1 to V4 by the pressure-sensitive devices S1 to S4 and each distance between the pressure pulse wave generation point and each of detection positions Q1 to Q4. A propagation speed of the pulse wave and the artery position can be determined by calculating coordinates at predetermined time intervals.