User-worn device for noninvasively measuring a physiological parameter of a user
The present disclosure relates to noninvasive methods, devices, and systems for measuring various blood constituents or analytes, such as glucose. In an embodiment, a light source comprises LEDs and super-luminescent LEDs. The light source emits light at at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm. In an embodiment, the detector comprises a plurality of photodetectors arranged in a special geometry comprising one of a substantially linear substantially equal spaced geometry, a substantially linear substantially non-equal spaced geometry, and a substantially grid geometry.
1. A user-worn device configured to non-invasively measure a physiological parameter of a user, the user-worn device comprising:
a first set of light emitting diodes (LEDs), the first set of LEDs comprising at least an LED configured to emit light at a first wavelength and an LED configured to emit light at a second wavelength;
a second set of LEDs spaced apart from the first set of LEDs, the second set of LEDs comprising at least an LED configured to emit light at the first wavelength and an LED configured to emit light at the second wavelength;
four photodiodes arranged on an interior surface of the user-worn device and configured to receive light after attenuation by tissue of the user;
a protrusion comprising:
a convex surface extending over the interior surface,
a plurality of openings in the convex surface extending through the protrusion and aligned with the four photodiodes, each opening defined by an opaque surface, and
a plurality of windows, each of the windows extending across a different one of the openings; and
one or more processors configured to receive one or more signals from at least one of the photodiodes and calculate a measurement of the physiological parameter of the user.
2. The user-worn device of claim 1 , wherein the windows comprise glass.
3. The user-worn device of claim 1 , wherein the windows comprise plastic.
4. The user-worn device of claim 1 further comprising:
a network interface configured to wirelessly communicate the measurement of the physiological parameter to at least one of: a mobile phone or a computer network;
a user interface comprising a touch-screen display, wherein the user interface is configured to display indicia responsive to the measurement of the physiological parameter;
a storage device configured to at least temporarily store at least the measurement; and
a strap configured to position the user-worn device on the user.
5. The user-worn device of claim 1 , wherein the opaque surface is configured to reduce light piping.
6. The user-worn device of claim 1 further comprising:
at least one wall extending between the interior surface and the protrusion,
wherein at least the interior surface, the wall and the protrusion form cavities, wherein the photodiodes are arranged on the interior surface within the cavities.
7. The user-worn device of claim 1 , wherein the physiological parameter comprises at least one of: methemoglobin, total hemoglobin, carboxyhemoglobin, or carbon monoxide.
8. The user-worn device of claim 1 , wherein the physiological parameter comprises oxygen or oxygen saturation.
9. The user-worn device of claim 1 , wherein the physiological parameter comprises trending information.
10. The user-worn device of claim 1 further comprising a thermistor.
11. The user-worn device of claim 1 , wherein the LEDs and the photodiodes are arranged on a same side of the tissue of the user.
12. The user-worn device of claim 1 , wherein the one or more processors are further configured to calculate a bulk measurement responsive to a positioning of the user-worn device.
13. The user-worn device of claim 1 , wherein, within each of the first and second sets of LEDs, any one LED is positioned within 2 mm to 4 mm of another.
14. The user-worn device of claim 1 , further comprising a third set of LEDs, the third set of LEDs comprising at least an LED configured to emit light at the first wavelength and an LED configured to emit light at the second wavelength.
15. The user-worn device of claim 1 , wherein the four photodiodes comprise first, second, third and fourth photodiodes and wherein the first photodiode and the second photodiode are arranged on the interior surface across from each other on opposite sides of a central point along a first axis, and the third photodiode and the fourth photodiode are arranged across from each other on opposite sides of the central point along a second axis which is different from the first axis.
16. The user-worn device of claim 1 , wherein the protrusion further comprises one or more extensions.
17. The user-worn device of claim 16 , wherein the one or more extensions surround a perimeter of the convex surface of the protrusion.
18. The user-worn device of claim 1 , wherein the protrusion further comprises one or more chamfered edges.
19. A user-worn device configured to non-invasively measure an oxygen saturation of a user, the user-worn device comprising:
a plurality of emitters configured to emit light, each of the emitters comprising at least two light emitting diodes (LEDs);
four photodiodes arranged within the user-worn device and configured to receive light after at least a portion of the light has been attenuated by tissue of the user;
a protrusion comprising a convex surface including separate openings extending through the protrusion and lined with opaque material, each opening positioned over a different one associated with each of the four photodiodes, the opaque material configured to reduce an amount of light reaching the photodiodes without being attenuated by the tissue;
optically transparent material within each of the openings; and
one or more processors configured to receive one or more signals from at least one of the four photodiodes and output measurements responsive to the one or more signals, the measurements indicative of the oxygen saturation of the user.
20. The user-worn device of claim 19 further comprising a thermistor.
21. The user-worn device of claim 20 , wherein the one or more processors are further configured to receive a temperature signal from the thermistor and adjust operation of the user-worn device responsive to the temperature signal.
22. The user-worn device of claim 21 , wherein the plurality of emitters comprise at least four emitters, and wherein each of the plurality of emitters comprises a respective set of at least three LEDs.
23. The user-worn device of claim 22 , wherein, within each respective set of at least three LEDs, the LEDs of the set are positioned within 2 mm to 4 mm of each other.
24. The user-worn device of claim 19 further comprising:
a network interface configured to wirelessly communicate at least the measurements of oxygen saturation to at least one of: a mobile phone or a computer network;
a user interface comprising a touch-screen display, wherein the user interface is configured to display indicia responsive to the measurements of oxygen saturation; and
a memory device configured to at least temporarily store at least the measurements of oxygen saturation.
25. The user-worn device of claim 19 , wherein the photodiodes comprise first, second, third and fourth photodiodes and wherein the first photodiode and the second photodiode are arranged across from each other on opposite sides of a central point along a first axis, and the third photodiode and the fourth photodiode are arranged across from each other on opposite sides of the central point along a second axis which is different from the first axis.
26. The user-worn device of claim 19 , wherein the optically transparent material is glass.
27. The user-worn device of claim 19 , wherein the optically transparent material is plastic.
28. A user-worn device configured to non-invasively measure an oxygen saturation of a user, the user-worn device comprising:
a first set of light emitting diodes (LEDs), the first set of LEDs comprising at least an LED configured to emit light at a first wavelength and an LED configured to emit light at a second wavelength;
a second set of LEDs spaced apart from the first set of LEDs, the second set of LEDs comprising at least an LED configured to emit light at the first wavelength and an LED configured to emit light at the second wavelength;
four photodiodes arranged in a quadrant configuration on an interior surface of the user-worn device and configured to receive light after at least a portion of the light has been attenuated by tissue of the user;
a thermistor configured to provide a temperature signal;
a protrusion arranged above the interior surface, the protrusion comprising:
a convex surface;
a plurality of openings in the convex surface, extending through the protrusion, and aligned with the four photodiodes, each opening defined by an opaque surface configured to reduce light piping; and
a plurality of transmissive windows, each of the transmissive windows extending across a different one of the openings;
at least one opaque wall extending between the interior surface and the protrusion, wherein at least the interior surface, the opaque wall and the protrusion form cavities, wherein the photodiodes are arranged on the interior surface within the cavities;
one or more processors configured to receive one or more signals from at least one of the photodiodes and calculate an oxygen saturation measurement of the user, the one or more processors further configured to receive the temperature signal;
a network interface configured to wirelessly communicate the oxygen saturation measurement to at least one of a mobile phone or an electronic network;
a user interface comprising a touch-screen display, wherein the user interface is configured to display indicia responsive to the oxygen saturation measurement of the user;
a storage device configured to at least temporarily store at least the measurement; and
a strap configured to position the user-worn device on the user.
29. The user-worn device of claim 28 , further comprising:
a driver configured to energize the first and second sets of LEDs; and
a front-end interface comprising one or more amplifiers and one or more analog to digital converters (ADCs), wherein the front-end interface receives the signals from the photodiodes, the one or more amplifiers amplify the signals and the one or more ADCs convert the signals to digital information, and wherein the processors receive the converted signals.
30. The user-worn device of claim 28 , wherein the protrusion further comprises one or more sidewalls extending at least partially around a perimeter of the convex surface.