SYSTEMS AND METHODS FOR SENSOR CALIBRATION IN PHOTOPLETHSYMOGRAPHY
First Claim
1. A photoplethysmography sensor, comprising:
- a light emitting element configured to emit light at a first wavelength and having an electrical input and an electrical output;
a light detecting element configured to receive the light emitted by the light emitting element; and
a calibration device coupled to the electrical input of the light emitting element to measure a first voltage present at the electrical input, and coupled to the electrical output of the light emitting element to measure a second voltage present at the electrical output,wherein the calibration device comprises a controller configured to determine a voltage difference between the first voltage and the second voltage when a current is passed through the light emitting element, and to determine calibration information for the sensor based on the voltage difference.
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Accused Products
Abstract
Various methods and systems for obtaining calibration coefficients for pulse oximeter sensors are provided. A method includes passing current through a light emitting element in an oximeter sensor and measuring, utilizing a first voltage sensing lead, a first voltage present at an electrical input of the light emitting element. The method also includes measuring, utilizing a second voltage sensing lead, a second voltage present at an electrical output of the light emitting element and determining a forward voltage of the light emitting element based on the first and second voltages. Utilizing the determined forward voltage, a wavelength of light emitted from the light emitting element is calculated. Utilizing the calculated wavelength of the emitted light, at least one calibration coefficient for the oximeter sensor is determined.
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Citations
32 Claims
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1. A photoplethysmography sensor, comprising:
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a light emitting element configured to emit light at a first wavelength and having an electrical input and an electrical output; a light detecting element configured to receive the light emitted by the light emitting element; and a calibration device coupled to the electrical input of the light emitting element to measure a first voltage present at the electrical input, and coupled to the electrical output of the light emitting element to measure a second voltage present at the electrical output, wherein the calibration device comprises a controller configured to determine a voltage difference between the first voltage and the second voltage when a current is passed through the light emitting element, and to determine calibration information for the sensor based on the voltage difference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A tangible, non-transitory machine readable medium, comprising:
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code configured to determine a voltage difference between a first voltage and a second voltage when a current is passed through a light emitting element disposed in a body of a photoplethysmography sensor, wherein the first voltage corresponds to a voltage level present at an electrical input of the light emitting element when the current is passed through the light emitting element, and the second voltage corresponds to a voltage level present at an electrical output of the light emitting element when the current is passed through the light emitting element; and code configured to determine, based on the voltage difference, one or more calibration coefficients or curves for conversion of received light signals to physiological parameters when the light emitting element emits light. - View Dependent Claims (17, 18)
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19. A photoplethysmography system, comprising:
a calibration device comprising; a current source configured to produce a current output; a first wire coupled to an electrical output of the current source and to an electrical input of a light emitting element of a photoplethymography sensor; a second wire coupled to an electrical output of the light emitting element and to an electrical input of the current source; a first voltage sensing lead coupled to the first wire before the electrical input of the light emitting diode and configured to measure a first voltage present in the first wire; a second voltage sensing lead coupled to the second wire after the electrical output of the light emitting diode and configured to measure a second voltage present in the second wire; and a controller configured to control the current source to produce the current output, to determine a voltage difference between the first voltage and the second voltage when the current output is passed through the light emitting element, and to determine calibration information for the photoplethymography sensor based on the voltage difference. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method, comprising:
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passing current through a light emitting element in an photoplethysmography sensor; measuring, utilizing a first voltage sensing lead, a first voltage present at an electrical input of the light emitting element; measuring, utilizing a second voltage sensing lead, a second voltage present at an electrical output of the light emitting element; determining a forward voltage of the light emitting element based on the first and second voltages; utilizing the determined forward voltage to calculate a wavelength of light emitted from the light emitting element; and utilizing the calculated wavelength of the emitted light to determine at least one calibration coefficient for the photoplethysmography sensor. - View Dependent Claims (31, 32)
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Specification