Fiber optic pressure sensor with temperature compensation and reference
First Claim
1. An intravascular blood pressure catheter of the fiber optic type comprising:
- a catheter member containing at least three optic fibers including a source fiber, a signal fiber and a reference fiber;
a catheter sensing tip including a pressure deformable diaphragm with an inside face, the diaphragm having a reflecting surface finish on the inside face;
means for directing a source of light through said source optic fiber toward said tip, said source of light being controlled in intensity;
a transparent body fastened to an end of said fibers into which body light emanates from said source fiber, said body including light-collimating lens means for redirecting light emanating from the source fiber into a column toward said reflecting surface finish and for directing reflected light therefrom falling on said lens means towards said signal optic fiber, said body further including mirror means positioned to receive a portion of the light transmitted into said body from said source optic fiber and oriented to reflect said portion into said reference fiber;
signal sensing means for detecting the intensity of reflected light being returned in said signal optic fiber, the amount of light collected by the signal fiber being a function of the pressure;
reference sensing means for detecting the intensity of reflected light being returned in said reference fiber; and
,control means responsive to the output of said reference sensing means to control the intensity of said source of light.
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Accused Products
Abstract
An intravascular catheter tip fiber optic pressure sensor wherein a lens element at the end of the fiber optic collimates the light emanating from the fiber and directs the light in a column towards a closely spaced reflecting diaphragm. The diaphragm is pressure responsive and modulates the focal length of the lens-diaphragm-mirror combination. Three optic fibers traverse the length of the hollow catheter tube, one carrying transmitted light to the tip, one carrying the reflected light from the diaphragm (i.e. the signal), and the third fiber carrying a reflected reference light. The reference detector provides a signal level to control the level of intensity of the light source.
233 Citations
11 Claims
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1. An intravascular blood pressure catheter of the fiber optic type comprising:
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a catheter member containing at least three optic fibers including a source fiber, a signal fiber and a reference fiber; a catheter sensing tip including a pressure deformable diaphragm with an inside face, the diaphragm having a reflecting surface finish on the inside face; means for directing a source of light through said source optic fiber toward said tip, said source of light being controlled in intensity; a transparent body fastened to an end of said fibers into which body light emanates from said source fiber, said body including light-collimating lens means for redirecting light emanating from the source fiber into a column toward said reflecting surface finish and for directing reflected light therefrom falling on said lens means towards said signal optic fiber, said body further including mirror means positioned to receive a portion of the light transmitted into said body from said source optic fiber and oriented to reflect said portion into said reference fiber; signal sensing means for detecting the intensity of reflected light being returned in said signal optic fiber, the amount of light collected by the signal fiber being a function of the pressure; reference sensing means for detecting the intensity of reflected light being returned in said reference fiber; and
,control means responsive to the output of said reference sensing means to control the intensity of said source of light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An intravascular blood pressure catheter of the fiber optic type comprising:
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a catheter member comprising a hollow catheter tube containing a transmit optic fiber and two return optic fibers, one of said return fibers being a signal fiber and the other of said return fibers a reference fiber; a catheter sensing tip including a pressure deformable diaphragm with an inside face, the diaphragm having a reflecting surface finish on the inside face; means for directing a source of light through said transmit optic fiber to said tip; light-collimating lens means at the tip of said transmit optic fiber for redirecting the light emanating from the fiber into a column to said diaphragm and for directing the light from said reflecting surface finish falling on said lens means towards said signal optic fiber; sensing means for detecting the intensity of reflected light in said signal optic fiber, the intensity of said detected light being a function of pressure; mirror means positioned to intercept a portion of the light emanating from said transmit fiber and to reflect said intercepted light to said reference optic fiber; and
,sensing means for detecting the intensity of reflected light in said reference optic fiber. - View Dependent Claims (11)
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Specification