PROBLEM TO BE SOLVED: To significantly reduce restrictions in positioning a living body part on a measurement position, to reduce operational burdens on a user, to enable a simple and compact circuit configuration, and to reduce power consumption.SOLUTION: A light detection unit 100 is configured such that sensor light 4 of a light emitting element 1 is made incident on a prism 2 made of a rectangular body plate from its incidence plane 2a, and the sensor light 4 repeats total reflection in the prism 2 and is emitted from an emission plane 2c and received by a light receiving element 3. When a living body part is brought into contact with the sensor surface of the prism 2, the living body part is irradiated with the sensor light from the prism 2 by the change of a refractive index on the contact surface to generate scattered light, a light component of the scattered light made incident again in the prism 2 is received by the light receiving element 3, and the light receiving signal is input to a signal processing unit 200 to detect the waveform of the volume pulse waves of the living body part.COPYRIGHT: (C)2012,JPO&INPIT【課題】測定位置への生体部位の位置合わせの制約を大幅に軽減してユーザの操作上の負担を減らし、しかも回路構成の簡単小型化と消費電力の低減を図る。【解決手段】光検出ユニット100を、長方体板からなるプリズム2にその入射面2aから発光素子1のセンサ光4を入射し、このセンサ光4がプリズム2内で全反射を繰り返して出射面2cから出射し受光素子3で受光されるように構成している。そして、プリズム2のセンサ面に生体部位が接触した場合に、その接触面における屈折率の変化によりプリズム2から生体部位にセンサ光4を照射して散乱光を発生させ、この散乱光のうちプリズム2内に再入射した光成分を受光素子3で受光し、その受光信号を信号処理ユニット200に入力することで上記生体部位の容積脈波の波形を検出するようにしたものである。【選択図】図1
