RX-0504
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`RX-0504.0001
`
`APL_MAS_ITC_00377841
`
`expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.
`This material is based upon work supported by the National Science Foundation under grants BES(cid:150)0440183 and BES(cid:150)0093916. Opinions, findings, conclusions, or recommendations
`
`16
`
`14
`
`12
`
`10
`
`time (sec)
`
`8
`
`16
`
`14
`
`12
`
`10
`
`time (sec)
`
`8
`
`6
`
`6
`
`4
`
`4
`
`2
`
`2
`
`Original Data
`
`Finger
`
`0
`
`-4
`
`-2
`
`024
`
`RED AC
`
`0
`
`-1.5
`
`-1
`
`-0.5
`
`0
`
`0.5
`
`1
`
`IR AC
`
`Pulse Oximeter Sensor
`
`14
`
`12
`
`10
`
`14
`
`12
`
`10
`
`8
`
`8
`
`time (sec)
`
`time (sec)
`
`6
`
`6
`
`Original Data
`
`4
`
`4
`
`2
`
`2
`
`0
`
`-0.6
`
`-0.4
`
`-0.2
`
`0
`
`0.2
`
`0.4
`
`0
`
`-1
`
`-0.5
`
`0
`
`0.5
`
`1
`
`IR AC
`
`RED AC
`
`mold to a curved surface.
`(cid:149)More ambient light noise due to holes in plastic and inability to
`(cid:149)Hard plastic material does not conform to most skin surfaces.
`resulting in poor efficiency and a smaller signal-to-noise ratio.
`(cid:149)One photodiode collects reflected red and infrared signals,
`
`primarily forward scattering. Increasing the reliability and quality of reflectance-mode signals will make these sensors a more attractive alternative to traditional transmission-mode designs.
`flexibility since they are only mounted on one side of the skin.However, these sensors are at a disadvantage since they collect only a fraction of the light reflected from tissue, which is
`surface, or reflection-mode, where light is reflected back towards the sensor and collected in the same region as the incident light. Reflectance-mode sensors offer more measurement-site
`the patients skin and underlying tissue. Pulse oximeter sensorscan either be transmission-mode, where light passes completely through the tissue and is collected on an opposing skin
`Pulse oximeters provide physiological information such as heart rate and blood oxygen saturation. These devices acquire measurements using red and infrared light that passes through
`
`Sponsor: National Science Foundation Research Experiences for Undergraduates Program; Advisor: Steve Warren, Ph.D.
`
`PreviousDesign
`
`(cid:149)Head-mounted sensors have also proven to be less obtrusive since theydo not impede
`(cid:149)Measurements from sites on the head are similar to those collected from sites on the finger.
`
`movement or use of the hands.
`
`25
`
`20
`
`15
`
`time (sec)
`
`10
`
`25
`
`20
`
`15
`
`time (sec)
`
`10
`
`5
`
`5
`
`Original Data
`
`Middle Temporal Artery
`
`0
`
`-2
`
`-1
`
`012
`
`0
`
`-2
`
`-1
`
`012
`
`IR AC
`
`RED AC
`
`(cid:149)Wrist
`(cid:149)Frontal branch (along hair line)
`(cid:149)Middle temporal artery (in front of ear)
`Viable and Unobtrusive Measuring Sites
`
`parameters.
`to calculate different physiological
`plethysmograms that can be used
`(cid:149)Provides time-domain
`are unimposing to the wearer.
`(cid:149)Small, Lightweight components
`
`collect viable data.
`previous design; less effort is required to
`(cid:149)Signal is also more reliable than with the
`ratio.
`(cid:149)Output signal exhibits greater signal-to-noise
`
`Measurement Site Comparison
`
`10
`
`9
`
`8
`
`7
`
`6
`
`time (sec)
`
`5
`
`4
`
`3
`
`2
`
`1
`
`0
`
`-3
`
`-2
`
`-1
`
`012
`
`RED AC
`
`10
`
`9
`
`8
`
`7
`
`6
`
`time (sec)
`
`5
`
`4
`
`3
`
`2
`
`1
`
`Original Data
`
`0
`
`-1
`
`-0.5
`
`0
`
`0.5
`
`1
`
`1.5
`
`IR AC
`
`several attempts to collect viable data.
`(cid:149)Signal is often difficult to obtain, requiring
`sensor movement.
`(cid:149)Signal-to-noise ratio is highly dependent on
`
`material and flexible design.
`(cid:149)Less susceptible to ambient noise due to opaque
`measurement site.
`(cid:149)Pliable material allows the sensor to conform to the
`forming a radial pattern around the source(s).
`(cid:149)Multiple photodiodes collect more of the reflected light,
`
`Optimized Design
`
`Optimization of Reflectance-Mode Pulse Oximeter Sensors
`
`Austin Wareing, B.S.
`
`1
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`APPLE 1039
`Apple v. Masimo
`IPR2022-01465
`
`