Optical sensor with multiple detectors or multiple emitters
Various noninvasive physiological sensors are described herein. Some implementations of the sensors described herein include multiple emitters and/or detectors positioned at various portions of a measurement site and configured to operate in either or both of transmittance and reflectance modes. In one implementation, a noninvasive physiological sensor includes a body portion configured to secure to a finger of a subject, an emitter operably positioned by the body portion at a first side of the finger and configured to emit light of one or more wavelengths into tissue of the finger, a first detector operably positioned by the body portion at a second side of the finger opposite the first side, and a second detector operably positioned by the body portion at a third side of the finger and offset approximately 90 degrees from the emitter with respect to an axis extending through at least a portion of the body portion.
1. A noninvasive physiological sensor configured to attach to a finger of a user, the noninvasive physiological sensor comprising:
a body portion configured to be secured to a finger of a user, the body portion comprising:
a first portion;
a second portion positioned axially from the first portion, the second portion wider than the first portion; and
an intermediate portion positioned between the first portion and the second portion and connected between the first portion and the second portion, the intermediate portion narrower than the first portion and the second portion;
a first emitter configured to emit light of one or more wavelengths into tissue of the finger of the user when the noninvasive physiological sensor is in use, wherein the first emitter is configured to be operably positioned by the body portion at a first side of the finger when the body portion is configured to be secured to the finger, the first emitter arranged on the second portion; and
a plurality of detectors, each of the plurality of detectors configured to detect at least a portion of the emitted light after attenuation by the tissue of the finger of the user when the noninvasive physiological sensor is in use, wherein each of the plurality of detectors is configured to generate at least one signal responsive to the detected light, and wherein the plurality of detectors comprises:
a first detector configured to be operably positioned by the body portion at a second side of the finger that is opposite the first side of the finger when the body portion is configured to be secured to the finger such that the first detector and the first emitter are substantially aligned with one another; and
a second detector configured to be operably positioned by the body portion at a third side of the finger when the body portion is configured to be secured to the finger such that the second detector is offset approximately 90 degrees from the first emitter with respect to an axis extending through at least a portion of the body portion, the first detector and the second detector arranged in an array on the first portion.
2. The noninvasive physiological sensor of claim 1 , wherein:
the noninvasive physiological sensor further comprises a second emitter configured to emit light of one or more wavelengths into the tissue of the finger of the user when the noninvasive physiological sensor is in use; and
the second emitter is operably positioned by the body portion at a fourth side of the finger that is opposite the third side of the finger when the body portion is secured to the finger such that the second emitter is offset approximately 90 degrees from the first emitter with respect to said axis extending through at least the portion of the body portion.
3. The noninvasive physiological sensor of claim 2 , wherein the second emitter is operably positioned by the body portion such that the second emitter is offset approximately 180 degrees from the second detector with respect to said axis extending through at least the portion of the body portion.
4. The noninvasive physiological sensor of claim 2 , wherein the first emitter and the second emitter are configured to be selectively activated such that only one of the first and second emitters is emitting light at a given time.
5. The noninvasive physiological sensor of claim 1 , wherein said axis extends through a center of a cross-section of the body portion.
6. The noninvasive physiological sensor of claim 1 , wherein the first emitter and the plurality of detectors are operably positioned by the body portion along a plane of a cross-section of the body portion when secured to the finger of the user.
7. The noninvasive physiological sensor of claim 1 , wherein said body portion is configured such that, when secured to the finger of the user, said axis extends along at least a portion of a longitudinal axis of the finger.
8. The noninvasive physiological sensor of claim 1 , wherein said first emitter is the only emitter of the noninvasive physiological sensor.
9. The noninvasive physiological sensor of claim 1 , wherein the body portion is configured to be transitioned from a first configuration when not secured to the finger of the user to a second configuration when secured to the finger of the user, and wherein the first and second configurations are different.
10. The noninvasive physiological sensor of claim 9 , wherein the body portion is configured to be substantially flat when in the first configuration.
11. The noninvasive physiological sensor of claim 9 , wherein the body portion is configured such that, when in the second configuration, the body portion is wrapped around the finger of the user.
12. The noninvasive physiological sensor of claim 9 , wherein, when the body portion is in said second configuration, a cross-section of the body portion is rounded.
13. The noninvasive physiological sensor of claim 1 , wherein the plurality of detectors further comprises a third detector operably positioned by the body portion at a fourth side of the finger when the body portion is secured to the finger such that the third detector is offset approximately 90 degrees from the first emitter with respect to said axis extending through said at least the portion of the body portion.
14. The noninvasive physiological sensor of claim 13 , wherein the third detector is operably positioned by the body portion at the fourth side of the finger when the body portion is secured to the finger such that the third detector is offset approximately 180 degrees from the second detector with respect to said axis extending through at least the portion of the body portion.
15. The noninvasive physiological sensor of claim 1 , wherein the first emitter and the plurality of detectors are in communication with a monitoring device configured to:
control operation of the first emitter;
receive said at least one signal generated by each of the plurality of detectors; and
determine one or more physiological parameters based on said at least one signal generated by each of the plurality of detectors.
16. The noninvasive physiological sensor of claim 15 , wherein the one or more physiological parameters comprises at least one of oxygen saturation, pulse rate, and glucose.
17. The noninvasive physiological sensor of claim 15 , further comprising a cable connected to the body portion and configured to transmit said at least one signal generated by each of the plurality of detectors to said monitoring device.
18. The noninvasive physiological sensor of claim 15 , wherein said monitoring device is configured to attach to a wrist of the user.
19. The noninvasive physiological sensor of claim 15 , wherein said monitoring device is configured to wirelessly transmit said determined one or more physiological parameters.
20. The noninvasive physiological sensor of claim 15 , wherein said noninvasive physiological sensor is configured to wirelessly transmit said at least one signal from each of the plurality of detectors to said monitoring device.