Symmetric LED array for pulse oximetry

• US 20080081966A1
• Filed: 09/29/2006
• Published: 04/03/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Debreczeny, Martin P.
• Granted Patent: US 8,175,667 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor

Abstract

A sensor for pulse oximeter systems is provided which comprises a first source of electromagnetic radiation configured to operate at a first wavelength, a second source of electromagnetic radiation configured to operate at a second wavelength and a third source of electromagnetic radiation configured to operate at a third wavelength. The first and third sources of electromagnetic radiation are symmetrically oriented about an axis.

Claims

1. A sensor comprising:

a first source of electromagnetic radiation configured to operate at a first wavelength;

a second source of electromagnetic radiation configured to operate at a second wavelength;

a third source of electromagnetic radiation configured to operate at a third wavelength; and

a photodetector configured to receive electromagnetic radiation from the blood-perfused tissue;

wherein the first and third sources of electromagnetic radiation are symmetrically disposed spatially relative to the second source.

2. The sensor of claim 1, wherein the first and third sources of electromagnetic radiation emit spectra that overlap at a half power level or greater of their respective emission maxima, the addition of the spectra causing a peak corresponding to a center wavelength.

3. The sensor of claim 1, wherein the first and third sources of electromagnetic radiation are configured to emit at a center wavelength in the range of 650 to 670 nm.

4. The sensor of claim 1 wherein the second source of electromagnetic radiation is configured to emit in the near-infrared region of the electromagnetic spectrum.

5. The sensor of claim 1 wherein the second source of electromagnetic radiation is configured to emit in the infrared region of the electromagnetic spectrum.

6. The sensor of claim 1 wherein the first and third sources of electromagnetic radiation emit in the red region of the electromagnetic spectrum.

7. The sensor of claim 1, wherein the first and third sources of electromagnetic radiation have peak emission spectra symmetrically disposed about a center wavelength, the first source having a peak emission at less than 670 nm and the third source having a peak emission at greater than 650 nm.

8. The system of claim 1, wherein the sensor comprises a curved surface configured to allow optical coupling of a patient'"'"'s finger with the first, second and third LEDs, and the photodetector.

9. The system of claim 8, wherein the curved surface inhibits axial movement of the patient'"'"'s finger.

10. A sensor comprising three light emitting diodes (LEDs), wherein two LEDs emit at wavelengths in the red region of the electromagnetic spectrum and are oriented symmetrically about an axis that bisects the other LED.

11. The sensor of claim 10, wherein the two LEDs emitting at wavelengths in the red region of the electromagnetic spectrum have maxima at the same wavelength.

12. A method of operating a pulse oximeter comprising:

transmitting electromagnetic radiation from a first light emitting diode (LED), a second LED and a third LED, wherein the first and third LEDs have maxima at wavelengths in the 600 to 800 rim range and are spatially symmetrical about a center wavelength, the first and third LEDs being configured to operate simultaneously;

generating a photoelectrical current corresponding to the electromagnetic radiation from the first, second and third LEDs;

computing physiological parameters based on the generated current.