Pulse oximeter
Inventors
Kondo, Nobuhiro • HANE, Yoshitaka • Fukuda, Kenichi • Yanai, Masamichi
Assignees
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Publication Number
US-11213227-B2
Publication Date
2022-01-04
Expiration Date
Abstract
A pulse oximeter includes a curved holder. A flexible substrate is coupled to a curved inner surface of an outer portion of the curved holder. A light emitter, a light receiver, and a reinforcement are coupled to a curved inner surface of the flexible substrate. The reinforcement is curved to extend in conformance with the curved form of the flexible substrate. The material of the reinforcement has a Young's modulus that is larger than the Young's modulus of the material of the outer portion and the Young's modulus of the material of an inner portion.
Core Innovation
The invention provides a pulse oximeter comprising a holder including a curved shape, a light emitter coupled to the holder to emit light inwardly from the holder, and a light receiver coupled to the holder at a position opposed to the light emitter to receive the light emitted from the light emitter. A reinforcement inside the holder extends from the light emitter to the light receiver in conformance with the curved shape of the holder, and the reinforcement material has a Young’s modulus that is greater than a Young’s modulus of a material of the holder.
A flexible circuit substrate is coupled to the curved inner surface of the holder, and the light emitter and light receiver are positioned on opposite longitudinal ends. The holder includes an inner portion and an outer portion, where the inner portion is softer than the outer portion and is more infrared-transmissive than the outer portion.
Optical shielding walls are provided around an emitter receptacle and a receiver receptacle to reduce ambient light and improve measurement accuracy. Blood oxygen saturation is measured based on ratios of received red light and received infrared light, and pulse may be measured from light fluctuations.
Claims Coverage
The independent claim defines a pulse oximeter with three core inventive features: a curved holder, opposed light emitter and light receiver arranged to emit light inwardly, and an internal reinforcement conforming to the curved shape with a Young’s modulus greater than that of the holder. The claim set further includes related structural refinements for the substrate, holder portions, optical transmission, and light shielding walls.
Curved holder with opposed emitter and receiver
A holder including a curved shape; a light emitter coupled to the holder to emit light inwardly from the holder; and a light receiver coupled to the holder at a position opposed to the light emitter to receive the light emitted from the light emitter.
Internal reinforcement conforming to the curved holder
A reinforcement inside the holder that extends from the light emitter to the light receiver in conformance with the curved shape of the holder.
Higher Young’s modulus reinforcement than holder
A material of the reinforcement has a Young's modulus that is greater than a Young's modulus of a material of the holder.
Plate-shaped substrate with flexural-rigidity constraint
A plate-shaped substrate inside the holder is electrically connected to the light emitter and the light receiver, and has lower flexural rigidity than the holder portion between the light emitter and the light receiver having the smallest cross-sectional area orthogonal to the extending direction.
Holder inner portion softer than outer portion
A holder with an inner portion and an outer portion, where the inner portion has lower hardness than the outer portion.
Inner portion higher transmittance than outer portion
The light emitter and light receiver are located between an inner surface of the outer portion and an outer surface of the inner portion, and the inner portion has higher transmittance than the outer portion with respect to a wavelength band of the light emitted from the light emitter.
Emitter and receiver light shield walls with viewing-direction relationships
An emitter light shield wall and a receiver light shield wall inside the holder, where the emitter light shield wall surrounds the light emitter as viewed from the light receiver and the receiver light shield wall surrounds the light receiver as viewed from the light emitter.
The claim coverage centers on the curved holder with opposed emitter and receiver, internal reinforcement conforming to the curved shape and having greater Young’s modulus than the holder, together with dependent refinements involving a plate-shaped substrate, holder portion property differences, optical transmission relationships, and light shielding walls.
Stated Advantages
increase overall flexural rigidity and maintain clamping on a finger
reduce ambient light and improve measurement accuracy
measurement of blood oxygen saturation based on ratios of received red and infrared light
pulse may be measured from light fluctuations
Documented Applications
Pulse measurement and blood oxygen saturation measurement by an optical physiological sensor using ratios of received red and infrared light and optionally light fluctuations.
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