Patent ID: 7128716

Claim:
A sensor part of a blood flowmeter for measuring a value on blood flow in tissue of a living body by emitting light to said tissue of a living body and receiving scattered light from said tissue of a living body, wherein the value on blood flow is calculated based on Doppler shifts in the scattered light, said sensor part comprising: a light emitter for emitting light to tissue of a living body, wherein said light emitter is a laser diode which emits light having a wavelength of about 1.3 μm; a light detector for receiving said scattered light from said tissue of a living body; a first shading structure on said semiconductor substrate for preventing light emitted from said light emitter from directly entering said light detector; and a second shading structure on said semiconductor substrate in front of said light detector, said second shading structure having a predetermined gap; wherein said light emitter and said light detector are integrated on a semiconductor substrate, and the sensor part includes an optical waveguide on said semiconductor substrate for outputting light emitted from said light emitter to said tissue of a living body by converting said light emitted from said light emitter into convergent light or parallel light, wherein said optical waveguide includes a bottom cladding, a core and a top cladding, and the light emitted from said light emitter propagates through the core, and wherein a ratio of said predetermined gap of said second shading structure to a lateral length of the semiconductor substrate is about 2%.