Apparatus and method of measuring blood flow in the foot
Inventors
Linders, David • Wolszon, Zoe • O'Brien, Jacob • Rogers, Madeline Diane • Grove, Lauren O'Neil • Wei, Dennis Lan-Bo • Lloyd, Emma Grace • Gerstley, Heather • Centracchio, Benjamin Thomas
Assignees
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Publication Number
US-11857303-B2
Publication Date
2024-01-02
Expiration Date
Abstract
An apparatus for measuring foot blood flow has a platform with a platform contact surface configured to receive a foot force from a user placing their foot on the contact surface. The apparatus also has a plurality of PPG sets (having at least one light source and at least one detector) extending through the platform contact surface, and a plurality of springs. Each PPG set is coupled with one or more of the springs to movably couple with the platform. In addition, each spring is biased to produce a biasing force via its coupled PPG set when the contact surface of the platform receives the foot. To maintain consistent pressure against the skin and good signal to noise ratio, each PPG set and its corresponding one or more springs are configured so that the biasing force has a magnitude that is substantially independent of the foot force magnitude.
Core Innovation
The invention relates to measuring blood flow in a foot using an apparatus that includes a platform with a platform contact surface configured to receive a foot force. A plurality of PPG sets extends through the platform contact surface, and each PPG set includes at least one light source and at least one light detector. A plurality of springs couples with the PPG sets to movably couple each PPG set with the platform when the platform contact surface receives the foot.
Each spring is biased to produce a biasing force via its coupled PPG set when the platform contact surface receives the foot. The PPG sets and their corresponding springs are configured so that the biasing force has a biasing force magnitude that is substantially independent of the foot force magnitude. In this way, the apparatus directs light into the foot and receives reflection of the light directed into the foot to support determining a blood flow characteristic from the received light.
In one implementation, the platform forms apertures at least in part containing respective PPG sets and springs, with the PPG sets configured to move within and at least in part outside of the apertures. A first PPG set normally extends above the platform contact surface and emits light at a first wavelength, and a second PPG set normally extends above the platform contact surface and emits light at a second wavelength that is different from the first wavelength.
Claims Coverage
The partial content includes three independent claims: one apparatus claim, a second apparatus claim focused on dual-wavelength PPG sets, and a method claim. Across these independent claims, the inventive coverage centers on biasing PPG sets toward a foot with a biasing force magnitude substantially independent of foot force magnitude, while directing light into the foot, receiving reflection, and determining a blood flow characteristic.
Spring-biased PPG sets with biasing force substantially independent of foot force
An apparatus for measuring blood flow in a foot comprising a platform with a platform contact surface configured to receive a foot force; a plurality of PPG sets extending through the platform contact surface, each PPG set having at least one light source and at least one light detector; a plurality of springs coupled with the PPG sets; each PPG set movably coupled with the platform by the one or more springs; each spring biased to produce a biasing force via its coupled PPG set when the platform contact surface receives the foot; and the PPG sets and corresponding one or more springs configured so that the biasing force has a biasing force magnitude that is substantially independent of the foot force magnitude.
Dual-wavelength PPG sets with separate aperture-contained springs and biasing force independent of foot force
An apparatus for measuring blood flow in a foot comprising a platform with a platform contact surface configured to receive a foot force; a first PPG set with a first light source emitting light at a first wavelength and a first light detector, the first PPG set normally extending above the platform contact surface; a second PPG set with a second light source emitting light at a second wavelength different from the first wavelength and a first light detector, the second PPG set normally extending above the platform contact surface; a first spring coupled with the first PPG set to movably couple it with the platform and biased to produce a first biasing force via the first PPG set when the platform contact surface receives the foot; a second spring coupled with the second PPG set to movably couple it with the platform and biased to produce a second biasing force via the second PPG set when the platform contact surface receives the foot; and the first PPG set and the first spring configured so that the first biasing force has a magnitude substantially independent of the foot force magnitude.
Method using apertured, biasing PPG sets to direct light into the foot and determine blood flow characteristic
A method of measuring blood flow in a foot comprising positioning a foot on a platform having a platform contact surface with a plurality of apertures and the platform having a plurality of PPG sets, each PPG set having at least one light source and at least one light detector and being biased toward the foot through one of the apertures in the platform contact surface; producing, by each PPG set, a biasing force with a magnitude substantially independent of the foot force; directing, by the PPG sets, light into the foot; receiving, by the PPG sets, reflection of the light directed into the foot; and determining a blood flow characteristic from the received light.
Across the independent claims, the shared inventive theme is using a platform and a plurality of PPG sets biased by springs so that a biasing-force magnitude is substantially independent of foot force magnitude. The claims further require light-directed interaction with the foot and determination of a blood flow characteristic, with additional independent-claim structure using two PPG sets at different wavelengths supported by separate apertures and springs.
Stated Advantages
The biasing force has a biasing force magnitude that is substantially independent of the foot force magnitude.
Documented Applications
Measuring blood flow in a foot.
Determining a blood flow characteristic from received light.
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