US 6,166,806 AGranted

Fiber optic catheter for accurate flow measurements

OwnerSwee Chuan Tjininventor

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Abstract

A two-fibre optic probe or sensor performs accurate measurements of fluids flowing within a remote vessels, such as blood flowing within arteries or veins or fluid flowing within pipes. One of the fibre transmits a light that is intercepted by a reflective surface. The reflective surface reflects the light out of the probe through an optically transparent window, located in the probe, and into the volume of the fluid. A portion of the emitted light scatters back, as backscatter, through the optical window into the probe where the light once again encounters the reflective surface. The reflective surface then directs the backscattered light directly into the terminal ends of the other fibre that receives the light. The detected light is used to measure the volume of the fluid at the area where the incident beam of the emitted light and the backscattered light overlaps.

Claims61

Dependent claims

A sensor for remote fluid flow measurements, said sensor comprising:

a flexible tube having an optical opening formed in a sidewall thereof;
first and second optical fibres disposed within said tube, said first and second optical fibres each having a longitudinal fibre axis and a terminal end disposed within said tube proximate said optical opening;
and
a single reflective surface disposed within said tube adjacent said terminal ends of said first and second optical fibres, said single reflective surface being separate from said terminal ends,
wherein said optical opening and a portion of said tube surrounding said terminal ends of said first and second optical fibres and said reflective surface define a cavity, said cavity being filled with an optical cement forming an optical window,
said single reflective surface being oriented such that light emitted from said terminal end of one of said first and second optical fibres is reflected by said single reflective surface in a direction having a component normal to the fibre axes through said optical cement into a measurement volume of the flow located outside and alongside said sensor, the reflected light being scattered within the measurement volume such that a portion of the scattered light that is within a field of view of the other of said first and second optical fibres is scattered back through said optical cement and is reflected by said single reflective surface into said terminal end of the other of said first and second optical fibres.

3 more elements

A sensor for remote fluid flow measurements, said sensor comprising:

a flexible tube having at least one optical opening formed in a sidewall thereof;
transmitting and receiving optical fibres disposed within said tube, said transmitting and receiving optical fibres each having a terminal end disposed within said tube proximate an associated opening of said at least one optical opening;
at least one reflective surface disposed within said tube adjacent said terminal ends of said transmitting and receiving optical fibres, a transmitting reflective surface of said at least one reflective surface being associated with said transmitting optical fibre and a receiving reflective surface of said at least one reflective surface being associated with said receiving optical fibre;
and
said at least one reflective surface being oriented such that light emitted from said terminal end of said transmitting optical fibre is reflected by said transmitting reflective surface out said optical opening associated with said transmitting optical fibre into said fluid and so that back scattered light within a field of view of said receiving optical fibre reenters said optical opening associated with said receiving optical fibre to be reflected by said receiving reflective surface directly into said terminal end of said receiving optical fibre, said transmitting reflective surface and said receiving reflective surface being formed so that said emitted light and said field of view, respectively, are focused.

2 more elements

A sensor for remote fluid flow measurements, said sensor comprising:

a flexible tube having at least one optical opening formed in a sidewall thereof;
transmitting and receiving optical fibres disposed within said tube, said transmitting and receiving optical fibres each having a terminal end disposed within said tube proximate an associated opening of said at least one optical opening;
at least one reflective surface disposed within said tube adjacent said terminal ends of said transmitting and receiving optical fibres, a transmitting reflective surface of said at least one reflective surface being associated with said transmitting optical fibre and a receiving reflective surface of said at least one reflective surface being associated with said receiving optical fibre;
said at least one reflective surface being oriented such that light emitted from said terminal end of said transmitting optical fibre is reflected by said transmitting reflective surface out said optical opening associated with said transmitting optical fibre into said fluid and so that back scattered light within a field of view of said receiving optical fibre reenters said optical opening associated with said receiving optical fibre to be reflected by said receiving reflective surface directly into said terminal end of said receiving optical fibre, said transmitting reflective surface and said receiving reflective surface being formed so that said emitted light and said field of view, respectively, are focused;
and
wherein said at least one optical opening and a portion of said tube surrounding said terminal ends of said transmitting and receiving optical fibres and said at least one reflective surface define a cavity, said cavity being filled with an optical cement forming at least one optical window.

3 more elements

Dependencies are inferred from the claim text.