MULTIPLE WAVELENGTH OPTICAL SENSOR

• US 20080242958A1
• Filed: 03/26/2008
• Published: 10/02/2008
• Est. Priority Date: 03/27/2007
• Status: Active Grant

• Current Assignee: Cercacor Laboratories
• Original Assignee: Cercacor Laboratories
• Inventors: Abdul-Hafiz, Yassir, Al-Ali, Ammar, Diab, Mohamed K., Panch, Arun, MacNeish, William Jack
• Granted Patent: US 8,781,544 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49113 the connectors connecting different bonding areas on the semiconductor or solid-state body to a common bonding area outside the body, e.g. converging wires
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/19105 in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

A multiple wavelength optical sensor has an emitter configured to radiate light having a plurality of wavelengths into a tissue site. The emitter comprises a plurality of LEDs configured in an array and connected within an electrical grid. A detector is configured to receive the light after absorption by pulsatile blood flow within the tissue site. The detector generates a sensor signal capable of being processed by a patient monitor so as to derive oxygen saturation, carboxyhemoglobin, methemoglobin and total hemoglobin.

Claims

1. A physiological sensor comprising:

an emitter that emits light having a plurality of wavelengths;

a detector that generates an output signal responsive to the emitted light after absorption by tissue;

an attachment assembly that removably attaches the emitter and the detector to tissue;

a spacer that provides a predetermined gap between the emitter and tissue when the emitter is attached to tissue; and

a light scattering medium disposed in a optical path between the emitter and tissue;

the spacer and the light scattering medium providing at least a substantially uniform illumination of tissue by the emitted light for each of the wavelengths.

2. The physiological sensor according to claim 1 wherein the light scattering medium comprises glass beads mixed with an encapsulant disposed proximate the spacer.

3. The physiological sensor according to claim 2 wherein the light scattering medium further comprises microspheres mixed with an epoxy disposed proximate the emitter.

4. The physiological sensor according to claim 3 wherein the emitter comprises an array of at least eight light emitting diodes emitting light generally centered around eight unique wavelengths.

5. The physiological sensor according to claim 4 wherein the emitter comprises an array of at least thirteen light emitting diodes emitting light generally centered around at least twelve unique wavelengths.

6. The physiological sensor according to claim 5 wherein the detector comprises at least one Si photodiode and at least one InGaAs photodiode connected in parallel.

7. The physiological sensor according to claim 6 wherein the detector comprises two Si photodiodes and four InGaAs photodiodes all connected in parallel.

8. The physiological sensor according to claim 7 wherein the light emitting diodes emit light within a first range of about 620-905 nm. and within a second range of about 1040-1270 nm.

9. A physiological sensor comprising:

an emitter configured to radiate light having a plurality of wavelengths into a tissue site;

the emitter comprises a plurality of LEDs disposed within an emitter ceramic substrate;

a detector configured to receive the light after absorption by pulsatile blood flow within the tissue site;

the detector generates a sensor signal capable of being processed by a patient monitor so as to derive total hemoglobin (Hbt);

the detector comprises a plurality of photodiodes disposed within a detector ceramic substrate; and

a first set of the photodiodes is responsive to a first set of the wavelengths and a second set of the photodiodes is responsive to a second set of the wavelengths.

10. The physiological sensor according to claim 9 further comprising:

a diffuser that scatters the radiated light so that a tissue site is uniformly illuminated across all of the wavelengths.

11. The physiological sensor according to claim 10 wherein the diffuser comprises at least one of:

a first encapsulate containing glass beads mounted in a spacer proximate the emitter ceramic substrate; and

a second encapsulate mixed with microspheres disposed on the LEDs within the emitter ceramic substrate.

12. The physiological sensor according to claim 11 wherein the photodiodes comprise at least one Si photodiode and at least one InGaAs photodiode connected in parallel.

13. The physiological sensor according to claim 12 wherein the LEDs radiate light generally centered around at least twelve unique wavelengths.

14. The physiological sensor according to claim 13 wherein the LEDs are mounted in an array of at least thirteen LEDs connected within an electrical grid.

15. The physiological sensor according to claim 14 wherein the twelve unique wavelengths comprise eight wavelengths within a first range of about 620-905 nm. and four wavelengths within a second range of about 1040-1270 nm.

16. A physiological sensor comprising:

a light source that radiates light having a plurality of wavelengths;

a diffuser that scatters the radiated light so that a tissue site is uniformly illuminated across all of the wavelengths; and

at least one detector that generates a sensor signal responsive to the radiated light after tissue attenuation.

17. The physiological sensor according to claim 16 wherein the light source comprises:

a ceramic substrate having conductors arranged as an electrical grid;

a plurality of LEDs mounted within the ceramic substrate in an array.

18. The physiological sensor according to claim 17 wherein the diffuser comprises:

a first encapsulant having microspheres disposed over the LEDs; and

a second encapsulant having glass beads disposed proximate the ceramic substrate.

19. The physiological sensor according to claim 18 further comprising a spacer disposed proximate the ceramic substrate so as to form a gap between the LEDs and the tissue site.

20. The physiological sensor according to claim 19 further comprising:

a connector that connects to a patient cable so as to communicate the sensor signal to a monitor;

a flexible coupling having an optical end proximate the light source and the detector and a connector end proximate the connector; and

the flexible coupling having conductors that communicate the sensor signal from the optical end to the connector end.