AMBIENT LIGHT USE IN PHYSIOLOGICAL SENSORS
The present disclosure describes the harvesting and use of ambient light in spectrophotometric systems so as to increase the energy efficiency of the systems. In one embodiment, the collected ambient light is filtered and/or converted into discrete wavelengths of light that can then be used in spectrophotometric applications. In one embodiment, the emitted light can then be collected and analyzed to derive various physiological parameters. In certain embodiments, the ambient light may be used in place of light that is electrically generated.
1 . A spectrophotometric sensor, comprising:
an ambient light collecting structure, wherein the ambient light comprises a continuum of wavelengths;
an optical modulator capable of modulating, filtering, or modulating and filtering the ambient light to transmit one or more discrete wavelengths;
a light emitter capable of emitting the one or more discrete wavelengths of light; and
a light detector capable of detecting the emitted light.
2 . The spectrophotometric sensor of claim 1 , comprising wireless transmission circuitry capable of wirelessly transmitting at least data derived from the light detector.
3 . The spectrophotometric sensor of claim 1 , wherein the ambient light collecting structure comprises at least one of a lens-like structure or a material of woven fibers.
4 . The spectrophotometric sensor of claim 1 , wherein the optical modulator comprises at least one of a Mach-Zehnder modulator or a grating filter.
5 . The spectrophotometric sensor of claim 1 , comprising an electrically powered light emitting device configured to supplement the emitted filtered ambient light.
6 . The spectrophotometric sensor of claim 5 , wherein the electrically powered light emitting device and the light emitter capable of emitting filtered ambient light are capable of combining their light emissions.
7 . A spectrophotometric sensor, comprising:
an ambient light collecting structure, wherein the ambient light comprises a continuum of wavelengths;
an optical modulator capable of converting a first set of one or more discrete wavelengths of ambient light to a second set of one or more discrete wavelengths and of filtering out wavelengths of ambient light other than the second set of one or more discrete wavelengths;
a light emitter capable of emitting the second set of one or more discrete wavelengths; and
a light detector capable of detecting the emitted light.
8 . The spectrophotometric sensor of claim 7 , comprising wireless transmission circuitry capable of wirelessly transmitting at least data derived from the light detector, wherein the wireless communication protocol used by the wireless transmission circuitry comprises at least one of IEEE 802.15, ZigBee, WirelessHart, MiWi, Bluetooth or IEEE 802.11 protocols.
9 . The spectrophotometric sensor of claim 7 , wherein the ambient light collecting structure comprises at least one of a lens-like structure or a material of woven fibers.
10 . The spectrophotometric sensor of claim 7 , wherein the optical modulator comprises at least one of a Mach-Zehnder modulator, Michelson modulator, Sagnac modulator, Fabry-Perot modulator, or a grating filter.
11 . The spectrophotometric sensor of claim 7 , comprising an electrically powered light emitting device configured to supplement the emitted second set of one or more discrete wavelengths.
12 . The spectrophotometric sensor of claim 11 , wherein the light emitter emits the one or more discrete wavelengths obtained from the optical modulator in combination with light emitted at the one or more discrete wavelengths by one or more LEDs
13 . A monitoring system, comprising:
a monitor, comprising:
a receiver capable of receiving a wireless signal;
a processor capable of processing the wireless signal to generate one or more physiological measurements; and
a display for displaying the one or more physiological measurements;
a wireless sensor, comprising:
an ambient light collector capable of collecting ambient light;
at least optical modulating structure capable of modulating, filtering, or modulating and filtering the ambient light to transmit only one or more discrete wavelengths, converting wavelengths of the ambient light into the one or more discrete wavelengths, or both filtering and converting the ambient light such that only discrete wavelengths are transmitted;
a light emitter capable of emitting the discrete wavelengths of light;
a light detector capable of detecting the emitted lights and generating a corresponding output; and
a transmitter capable of transmitting the wireless signal in response to the output.
14 . The monitoring system of claim 13 , wherein the sensor comprises an electrically powered light emitting device configured to supplement the emitted discrete wavelengths of light.
15 . The monitoring system of claim 14 , wherein the wireless sensor comprises a processor capable of processing the corresponding output or a signal derived from the corresponding output to generate the wireless signal.
16 . A method of transmitting light into a patient tissue, comprising the acts of:
collecting ambient light comprising a continuum of wavelengths;
transmitting one or more discrete wavelengths of light by modulating, filtering, or modulating and filtering the ambient light to remove all but the one or more discrete wavelengths, by converting other wavelengths of the ambient light to the one or more discrete wavelengths, or by performing one or both of filtering and converting to generate the one or more discrete wavelengths of light from the ambient light; and
directing the one or more discrete wavelengths of light into a patient tissue.
17 . The method of claim 16 , comprising emitting light from an electrically powered light emitting device in conjunction with the one or more discrete wavelengths of light directed into the patient tissue.
18 . The method of claim 16 , wherein transmitting the one or more discrete wavelengths comprises transmitting two discrete wavelengths of light in alternation.
19 . The method of claim 16 , comprising collecting light emerging from the patient tissue and processing the collected light to derive one or more physiological measurements.
20 . The method of claim 16 , wherein the ambient light is filtered or converted using at least one of a Mach-Zehnder modulator or a grating filter.