Device for monitoring cardiovascular signals and fiber optic coupler phonocardio sensor therefor

Claim 1

A fiber optic coupler cardiovascular sound sensor constructed of only dielectric material for use in a non-evasive method of monitoring cardiovascular sounds, including sub-audible sound, without danger of burn or electrical shock hazard to a patient or invading the interior of said patient's body, said sensor comprising a plurality of input optical fibers each having a core, said cores of said optical fibers being merged and fused in a waist region to form a common optical core wherefrom a plurality of output optical fibers emerge, said fiber optic coupler sensor distributing light energy incident to one of said input optical fibers between said plurality of output optical fibers, a membrane encapsulating said waist region and having a refractive index variable with stress applied thereto such that said incident light energy is distributed between said plurality of output optical fibers as a function of said stress applied, a support member with a cavity and an aperture therein, said aperture extending through said support member to said cavity, said waist region encapsulated in said membrane disposed in said cavity such that said stress applied is to responsive to cardiovascular sounds coupled to said cavity through said support member, said membrane including at least one curved surface so that said membrane has a non-uniform thickness with a thinnest section, said waist region being encapsulated in said membrane so that said waist region extends through said thinnest section, thereby enhancing the sensitivity thereof to said cardiovascular sounds; a taut film secured across an opening of said aperture, and means for converting said distributed light energy emerging from said output optical fibers into corresponding electrical signals, thereby monitoring said cardiovascular sounds, including said sub-audible sound, without danger of burn or electrical shock hazard to said patient.