US 6,088,607 A · Low noise optical probe

Abstract

An optical probe for measurements, which is particularly suited to reduce noise in measurements taken on an easily compressible material, such as a finger, a toe, a forehead, an earlobe, or a lip. The probe includes a base having an aperture which leads to a chamber. The base is placed adjacent a portion of the material, the chamber being placed directly adjacent any easily compressible portion of the material. A photodetector is located within the chamber and does not contact the material. A light emitting diode (LED) is affixed to the material, opposite the photodetector and above the chamber. The material which is supported by the aperture and therefore rests above or has intruded into the chamber is inhibited from compression since nothing comes in contact with this portion of the material, even when the material moves. Thus, light from the LED is directed through a stabilized portion of the material, i.e., the optical path length through which light travels is stabilized, even during motion of the material. This reduces noise in the signal measured by the photodetector. A scattering medium is interposed between the LED and the material, between the material and the photodetector, or between the LED and the material as well as between the material and the photodetector. The scattering medium is used to improve the signal-to-noise ratio of the received optical signal.

Claims9

Dependent claims

An oximeter sensor for measuring electromagnetic energy which has been attenuated by a living flesh material, said sensor comprising:

a light source;
a base having a thickness, said base being positioned adjacent said flesh material when said optical probe is positioned for use;
an aperture in said base, said aperture forming an entrance to a chamber which extends into said base, said aperture and chamber having a width of at least 3 mm and, said chamber having a particular depth such that the flesh material which penetrates into the chamber via said aperture is not substantially compressed with change in pressure between said flesh material and a surface defining said aperture typically expected from a patient;
and
a detector located within said chamber such that when said oximeter sensor is in use, said detector and light source are generally in axial alignment for transmission, said detector separated from any of said portion of flesh material which has penetrated into said chamber, said detector receiving electromagnetic energy transmitted by said light source and through said flesh material, said detector operative to generate a signal in response to said electromagnetic radiation, said width of said aperture being sized to reduce motion artifacts in said signal due to motion typically expected for a living patient.

2 more elements

Dependencies are inferred from the claim text.

Low noise optical probe

Life of this patent

Low noise optical probe

Life of this patent

Abstract

Claims9