Dab tsi yog lub luag haujlwm ntawm diodes hauv kev saib xyuas lub plawv dhia ntawm lub ntsej muag ntse?

1, PPG thev naus laus zis txoj cai: cov txheej txheem tseem ceeb ntawm diodes
Kev saib xyuas lub plawv dhia ntawm lub ntsej muag ntse yog feem ntau raws li PPG thev naus laus zis, thiab nws cov txheej txheem tseem ceeb suav nrog plaub kauj ruam: lub teeb pom kev zoo, teeb pom kev nkag mus thiab kev xav, lub teeb pom kev txais tos, thiab teeb liab ua. Nyob rau hauv cov txheej txheem no, diodes ua si ob lub luag hauj lwm ntawm lub teeb qhov chaw emission thiab lub teeb liab txais tos:

Lub teeb pom kev zoo: LED diode (feem ntau lub teeb ntsuab, wavelength 530nm) ua rau hauv lub dab teg tsis tu ncua emits lub teeb uas nkag mus rau ntawm daim tawv nqaij. Lub teeb ntsuab tau txais txiaj ntsig zoo los ntawm hemoglobin hauv cov ntshav, thaum lub teeb tsis nqus tau rov qab mus rau ntawm daim tawv nqaij. Qhov kev xaiv wavelength no yog ua raws li qhov muaj zog nqus cov yam ntxwv ntawm cov ntshav ntawm lub teeb ntsuab, uas tuaj yeem ua kom pom qhov sib txawv loj tshaj plaws.
Kev txais cov teeb liab kho qhov muag: Photodiodes (xws li Vishay's VEMD2704) yog lub luag haujlwm kom tau txais cov teeb liab pom kev pom thiab hloov mus rau hauv cov teeb liab hluav taws xob. Thaum lub plawv tso ntshav, cov hlab ntsha ntawm cov hlab ntsha hloov pauv ib ntus, ua rau muaj kev hloov pauv ntawm qhov pom kev siv lub teeb. Photodiodes tsim hluav taws xob teeb liab synchronized nrog lub plawv dhia los ntawm kev ntes cov hloov maj mam hloov hauv lub teeb siv.
Kev ua cov teeb liab: Cov ua tau - nyob rau hauv nti ntawm lub wristband lim, amplifies, thiab soj ntsuam cov hluav taws xob teeb liab siv algorithms, thaum kawg xam tus nqi lub plawv dhia. Piv txwv li, Xiaomi Mi Band 7 ua tiav kev tiv thaiv electrostatic los ntawm TVS diode (ESD5641D12) ntim rau hauv DFN2x2-3L, kom ntseeg tau tias cov teeb liab kis tau zoo.

2, Kev xaiv ntaus ntawv: hloov mus rau kev ua tau zoo thiab cov xwm txheej
Kev ua haujlwm ntawm photodiodes ncaj qha txiav txim siab qhov tseeb thiab kev ntseeg siab ntawm kev saib xyuas lub plawv dhia. Hauv kev siv tswv yim, cov ntsiab lus tseem ceeb hauv qab no yuav tsum tau ua kom tiav:

Cov lus teb wavelength: Kev saib xyuas lub plawv yuav tsum tau npog lub teeb ntsuab (530nm) band, thaum kuaj ntshav oxygen xav tau los txhawb ob lub teeb liab (660nm) thiab lub teeb infrared (940nm). Qee qhov siab -wristbands, xws li Apple Watch, siv ntau lub wavelength photodiodes kom ua tiav synchronous saib xyuas lub plawv dhia thiab cov ntshav oxygen los ntawm kev txheeb xyuas qhov sib txawv ntawm lub teeb nqus ntawm qhov sib txawv wavelengths.
rhiab heev thiab teeb liab-rau- suab nrov piv: Nyob rau hauv lub zog, qhov kev siv ntawm lub teeb reflection ntawm daim tawv nqaij nto fluctuates heev, yuav tsum photodiodes muaj siab rhiab heev rau ntes tsis muaj zog cov cim. Vishay's VEMD2704 txhim kho lub teeb liab- rau- suab nrov piv rau ntau tshaj ob npaug ntawm cov khoom siv ib txwm siv los ntawm kev ua kom zoo dua lub teeb infrared lub teeb teb nkhaus, txo cov kev cuam tshuam ntawm cov khoom cuav.
Pob loj thiab lub zog noj: Cov wristbands ntse muaj cov kev cai nruj rau cov khoom siv me me thiab siv hluav taws xob tsawg. Piv txwv li, VEMD2704 tau txais 1.8mm × 2.0mm micro pob nrog lub zog siv tsuas yog 0.1mW, uas tuaj yeem ua tau raws li lub roj teeb lub neej ntawm lub dab teg ntev txog 7 hnub.

3, Daim Ntawv Thov Kev Sib Tw: Kev cuam tshuam los ntawm Environmental thiab Physiological Factors
Txawm hais tias muaj kev loj hlob ntawm PPG thev naus laus zis, nws tseem ntsib ntau yam teeb meem hauv kev siv tswv yim, uas yuav tsum tau hais los ntawm kev sib xyaw ntawm kev xaiv diode thiab algorithm optimization.

Ib puag ncig teeb pom kev cuam tshuam: Lub teeb muaj zog (xws li lub hnub ci) tuaj yeem ua rau lub teeb ci ntawm photodiodes, ua rau muaj teeb meem cuam tshuam. Cov tshuaj muaj xws li:
Siv cov ntxaij lim dej nqaim, tsuas yog lub hom phiaj wavelength (xws li 530nm) raug tso cai hla;
Dynamically kho lub LED tsav tam sim no kom sib npaug lub teeb liab lub zog thiab ib puag ncig teeb pom kev zoo.
Tsab ntawv tsa suab: Lub caj npab viav vias lossis cov leeg nqaij tuaj yeem hloov txoj kev teeb ntawm daim tawv nqaij, ua rau muaj teeb meem hloov pauv. Piv txwv li, cov ntaub ntawv lub plawv dhia ntawm lub dab teg tej zaum yuav txawv txav ib ntus thaum khiav. Optimization cov lus qhia muaj xws li:
Xaiv cov photodiodes uas muaj zog tiv thaiv - muaj peev xwm cuam tshuam (xws li cov khoom siv hluav taws xob tsawg);
Ua ke cov ntaub ntawv acceleration sensor, tshem tawm kev cuam tshuam kev txav los ntawm algorithms.
Cov tawv nqaij sib txawv: cov tawv nqaij tsaus lossis tattoos tuaj yeem txo qhov kev cuam tshuam ntawm lub teeb thiab cuam tshuam rau kev saib xyuas qhov tseeb. Qee lub wristbands daws qhov teeb meem no los ntawm kev nce LED tsav lub zog lossis siv ntau lub teeb lub teeb (xws li lub teeb liab thiab ntsuab).

4, Technical Optimization: Innovation ntawm Devices rau Systems
Txhawm rau txhim kho qib kev kho mob qhov tseeb ntawm kev saib xyuas lub plawv dhia, kev lag luam tau txhawb kev hloov kho thev naus laus zis los ntawm ob theem: kev tsim khoom siv thiab kev sib koom ua ke.

Device innovation:
Kev sib koom ua ke ntau lub wavelength: Piv txwv li, ROHM's BPW34 photodiode integrates ntsuab, liab, thiab infrared sensors ntawm ib nti kom ua tiav synchronous saib xyuas lub plawv dhia, ntshav oxygen, thiab ntshav siab.
Saj zawg zog substrate: 3D kua diode (3D LD) thev naus laus zis los ntawm City University of Hong Kong ua tiav cov hws unidirectional kis tau tus mob thiab txhim kho breathability los ntawm kev tsim heterogeneous wetting microstructures, daws teeb meem drift teeb meem tshwm sim los ntawm hws tsub zuj zuj nyob rau hauv tsoos wristbands.
Algorithm optimization:
Cov qauv kev kawm sib sib zog nqus: Huawei GT series wristbands siv convolutional neural networks (CNN) los tshuaj xyuas cov yam ntxwv waveform ntawm PPG cov cim, paub qhov txawv ntawm lub plawv dhia tiag tiag thiab cov khoom siv dag zog, thiab txo qis lub plawv dhia tsis zoo rau hauv ± 1bpm.
Multi sensor fusion: Sib txuas ECG electrodes nrog PPG sensors, ntsuas lub plawv dhia cov ntaub ntawv los ntawm kev sib piv lub sij hawm ncua ntawm ECG cov cim thiab cov teeb liab kho qhov muag, thiab txhim kho qhov tseeb hauv qhov chaw muaj zog.