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 sensor of a user-worn device configurable to non-invasively measure a pulse rate of a user, the sensor comprising:
a plurality of light emitting diodes (LEDs);
four photodiodes arranged on a photodiode mount and configured to receive light attenuated by tissue of the user; and
a cover separate from the photodiode mount and comprising:
a raised surface configured to contact the tissue of a measurement site when the user-worn device is worn by the user, the raised surface being at least partially flat;
a perimeter including a sloping section configured to contact the tissue of the measurement site when the user-worn device is worn by the user, the perimeter surrounding the raised surface, the sloping section sloping toward the raised surface and the tissue of the measurement site when the user-worn device is worn by the user, the perimeter providing a transition to the raised surface;
four through holes within the raised surface, each through hole extending entirely through the raised surface and aligned with a different one of the four photodiodes; and
opaque material blocking light from reaching each of the four photodiodes without traversing its corresponding through hole,
the cover extending across the four photodiodes and configured to mold the tissue of the measurement site when the user-worn device is worn by the user.
2. The sensor of claim 1 , wherein each through hole comprises optically transmissive material.
3. The sensor of claim 2 , wherein the optically transmissive material is within each of the through holes.
4. The sensor of claim 1 , wherein the sloping section of the perimeter is curved.
5. The sensor of claim 1 , wherein the raised surface is at least partially curved.
6. The sensor of claim 1 , wherein the plurality of LEDs and the four photodiodes are arranged on a same side of the tissue of the user.
7. The sensor of claim 1 , wherein the plurality of LEDs comprises:
a first set of LEDs, the first set of LEDs comprising at least an LED configured to emit visible light and an LED configured to emit near-infrared light; and
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 visible light and an LED configured to emit near-infrared light.
8. The sensor of claim 1 , wherein the user-worn device is further configurable to non-invasively measure an oxygen saturation of the user.
9. The sensor of claim 1 , wherein each of the through holes comprises an opaque lateral surface configured to avoid light piping through the cover.
10. The sensor of claim 1 further comprising:
at least one opaque wall extending between the photodiode mount and the cover, wherein at least the photodiode mount, the opaque wall, and the cover form one or more cavities, wherein the four photodiodes are arranged within the cavities.
11. The sensor of claim 1 , wherein the four photodiodes are optically separated from one another.
12. The sensor of claim 1 , wherein the four photodiodes are arranged in a grid pattern.
13. The sensor of claim 12 , wherein the four photodiodes are arranged in the grid pattern such that a first photodiodes and a second photodiodes are arranged across from each other on opposite sides of a central point along a first axis, and a third photodiodes and a fourth photodiodes are arranged across from each other on opposite sides of the central point along a second axis which is perpendicular to the first axis.
14. The sensor of claim 1 , further comprising:
a thermistor configured to output a temperature signal, wherein the user-worn device is further configurable to adjust operation responsive to the temperature signal.
15. The sensor of claim 14 , wherein the temperature signal is responsive to a temperature of the tissue of the user.
16. The sensor of claim 1 , wherein the cover further comprises one or more chamfered edges.
17. The sensor of claim 1 , wherein the user-worn device is configured to be worn on an arm of the user.
18. A user-worn device configurable to non-invasively measure a pulse rate of a user, the user-worn device comprising:
at least three light emitting diodes (LEDs);
four photodiodes arranged on a photodiode mount and configured to receive light attenuated by tissue of the user;
a cover separate from the photodiode mount and comprising a raised surface configured to contact the tissue of a measurement site when the user-worn device is worn by the user and a perimeter including a curved section configured to contact the tissue of the measurement site when the user-worn device is worn by the user, the perimeter surrounding the raised surface, the curved section extending toward the raised surface and the tissue of the measurement site when the user-worn device is worn by the user, the perimeter providing a transition to the raised surface, the raised surface being at least partially flat, the cover comprising a plurality of through holes within the raised surface of the cover, each through hole aligned with a different one of the four photodiodes, each through hole comprising optically transmissive material, each through hole further comprising opaque lateral surfaces configured to avoid light piping through the cover, the cover extending across the photodiode mount and configured to mold the tissue of the measurement site when the user-worn device is worn by the user;
one or more processors configurable to receive one or more signals from at least one of the four photodiodes and calculate a measurement of the pulse rate of the user; and
a user interface comprising a display, wherein the user interface is configurable to display indicia responsive to the measurement of the pulse rate of the user.
19. The user-worn device of claim 18 , wherein the optically transmissive material is within each of the through holes and comprises a window.
20. The user-worn device of claim 18 , wherein the raised surface is at least partially curved.
21. The user-worn device of claim 18 , wherein the at least three LEDs comprise:
a first set of LEDs, the first set of LEDs comprising at least an LED configured to emit visible light and an LED configured to emit near-infrared light; and
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 visible light and an LED configured to emit near-infrared light.
22. The user-worn device of claim 21 , wherein the at least three LEDs and the four photodiodes are arranged on a same side of the tissue of the user.
23. The user-worn device of claim 18 , wherein the user-worn device is further configurable to non-invasively measure an oxygen saturation of the user.
24. The user-worn device of claim 18 , further comprising:
a thermistor configured to output a temperature signal,
wherein the one or more processors are further configurable to:
receive the temperature signal; and
adjust operation of the user-worn device responsive to the temperature signal.
25. The user-worn device of claim 18 further comprising:
a network interface configurable to wirelessly communicate measurements of the pulse rate to a mobile phone or a computer network;
a memory configurable to at least temporarily store at least the measurements; and
a strap configured to position the user-worn device on the user.
26. The user-worn device of claim 25 , wherein the one or more processors are further configurable to execute software to cause the user-worn device to calculate the measurement of the pulse rate of the user.
27. The user-worn device of claim 26 , wherein the one or more processors are further configurable to download software.
28. The user-worn device of claim 27 , wherein the user-worn device is configured to be worn on an arm of the user.
29. The user-worn device of claim 28 further comprising:
at least one opaque wall extending between the photodiode mount and the cover, wherein at least the photodiode mount, the opaque wall, and the cover form one or more cavities, wherein the four photodiodes are arranged within the cavities,
wherein the cover further comprises one or more chamfered edges.