Multiple wavelength sensor substrate
A physiological sensor has emitters configured to transmit optical radiation having multiple wavelengths in response to corresponding drive currents. A thermal mass is disposed proximate the emitters so as to stabilize a bulk temperature for the emitters. A temperature sensor is thermally coupled to the thermal mass. The temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature.
1. A physiological sensor comprising:
a plurality of emitters configured to transmit optical radiation having a plurality of wavelengths in response to a corresponding plurality of drive currents, the plurality of emitters including a substrate;
a thermal mass disposed proximate the emitters and within the substrate so as to stabilize a bulk temperature for the emitters; and
a temperature sensor thermally coupled to the thermal mass,
wherein the temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature.
2. The physiological sensor according to claim 1 wherein the substrate has a first side and a second side,
wherein the emitters are mounted to the first side, and
wherein the temperature sensor is mounted to the second side.
3. The physiological sensor according to claim 2 wherein the temperature sensor is a thermistor and the emitters are LEDs.
4. The physiological sensor according to claim 3 :
wherein the thermal mass is a plurality of layers of the substrate.
5. The physiological sensor of claim 4 wherein each of the layers of the thermal mass is substantially copper clad.
6. The physiological sensor according to claim 1 :
wherein the thermal mass is disposed within the substrate proximate the light emitting sources and the temperature sensor.
7. A physiological sensor capable of emitting light into tissue and producing an output signal usable to determine one or more physiological parameters of a patient, the physiological sensor comprising:
a thermal mass;
a plurality of light emitting sources, including a substrate of the plurality of light emitting sources, thermally coupled to the thermal mass, the sources having a corresponding plurality of operating wavelengths, the thermal mass disposed within the substrate;
a temperature sensor thermally coupled to the thermal mass and capable of determining a bulk temperature for the thermal mass, the operating wavelengths dependent on the bulk temperature; and
a detector capable of detecting light emitted by the light emitting sources after tissue attenuation, wherein the detector is capable of outputting a signal usable to determine one or more physiological parameters of a patient based upon the operating wavelengths.
8. The physiological sensor according to claim 7 :
wherein the thermal mass is disposed within the substrate proximate the light emitting sources and the temperature sensor.
9. The physiological sensor according to claim 7 wherein the temperature sensor comprises a thermistor.
10. The physiological sensor according to claim 9 wherein the light emitting sources are disposed on a first side of the substrate and the temperature sensor is disposed on a second side of the substrate.
11. The physiological sensor according to claim 7 wherein the thermal mass is a plurality of layers of the substrate.
12. The physiological sensor of claim 11 wherein each of the layers of the thermal mass is substantially copper clad.
13. In a physiological sensor adapted to determine a physiological parameter using a plurality of light emitting sources with emission wavelengths affected by one or more dynamic operating parameters, a sensor method comprising:
providing a thermal mass disposed within the substrate proximate the light emitting sources and a temperature sensor thermally coupled to the thermal mass;
transmitting optical radiation from the plurality of light emitting sources into body tissue;
detecting the optical radiation after tissue attenuation; and
determining a plurality of operating wavelengths of the light emitting sources dependent on a bulk temperature of the light emitting sources so that one or more physiological parameters of a patient can be determined based upon the operating wavelengths.
14. The physiological sensor method according to claim 13 wherein the determining step comprises stabilizing the bulk temperature for the light emitting sources.
15. The physiological sensor method according to claim 14 wherein the determining further comprises thermally coupling a thermistor to the light emitting sources so as to indicate the bulk temperature.
16. The physiological sensor method according to claim 15 further comprising disposing the thermistor proximate the light emitting sources.
17. The physiological sensor according to claim 13 wherein the thermal mass is disposed within the substrate proximate the light emitting sources and the temperature sensor.
18. The physiological sensor method according to claim 13 wherein the thermal mass is a plurality of layers of the substrate.
19. The physiological sensor method according to claim 18 wherein each of the layers of the thermal mass is substantially copper clad.
20. In a physiological sensor adapted to determine a physiological parameter using a plurality of light emitting sources with emission wavelengths affected by one or more dynamic operating parameters, a sensor method comprising:
providing a thermal mass disposed within a substrate of the light emitting sources and a temperature sensor thermally coupled to the thermal mass;
transmitting optical radiation from the plurality of light emitting sources into body tissue;
detecting the optical radiation after tissue attenuation; and
indicating an operating wavelength for each of the plurality of light emitting sources.
21. The physiological sensor method according to claim 20 wherein the indicating step comprises measuring a bulk temperature for the light emitting sources.
22. The physiological sensor method according to claim 21 wherein the indicating further comprises utilizing a thermistor thermally coupled to the light emitting sources so as to measure a bulk temperature.
23. The physiological sensor according to claim 20 wherein the thermal mass is disposed within the substrate proximate the light emitting sources and the temperature sensor.
24. The physiological sensor method according to claim 20 wherein the thermal mass is a plurality of layers of the substrate.
25. The physiological sensor method according to claim 24 wherein each of the layers of the thermal mass is substantially copper clad.
26. A physiological sensor comprising:
a plurality of emitters configured to transmit optical radiation having a plurality of wavelengths in response to a corresponding plurality of drive currents;
a thermal mass disposed proximate the emitters and within a substrate so as to stabilize a bulk temperature for the emitters; and
a temperature sensor thermally coupled to the thermal mass,
wherein the temperature sensor provides a temperature sensor output responsive to the bulk temperature so that the wavelengths are determinable as a function of the drive currents and the bulk temperature;
a substrate having a top side and a bottom side,
wherein the emitters are mounted to the top side, and
wherein the temperature sensor is mounted to the bottom side.
27. The physiological sensor according to claim 26 wherein the temperature sensor is a thermistor and the emitters are LEDs.
28. The physiological sensor according to claim 26 wherein the thermal mass is a plurality of layers of the substrate.
29. The physiological sensor of claim 28 wherein each of the layers of the thermal mass is substantially copper clad.
30. The physiological sensor according to claim 26 :
wherein the light emitting sources and the temperature sensor are disposed on the substrate, and
wherein the thermal mass is disposed within the substrate proximate the light emitting sources and the temperature sensor.