Ultrasonic sensor kev ua haujlwm
Piezoelectric ultrasonic sensors siv lub hauv paus ntsiab lus ntawm piezoelectric nyhuv ntawm piezoelectric cov ntaub ntawv ua hauj lwm. Feem ntau siv cov khoom siv rhiab heev feem ntau suav nrog piezoelectric crystals thiab piezoelectric ceramics.
Raws li qhov sib txawv ntawm qhov zoo thiab thim rov qab piezoelectric los, piezoelectric ultrasonic sensors muab faib ua generators (transmitting probes) thiab receivers (receiving probes). Raws li cov qauv thiab hom yoj siv, lawv tuaj yeem muab faib ua cov kev sojntsuam ncaj nraim, kev sojntsuam yoj saum npoo av, thiab Lamb yoj sojntsuam, lub kaum ntse ntse sib txawv, ob lub ntsej muag siv lead ua, tsom rau kev sojntsuam, dej immersion sojntsuam, tshuaj tsuag dej thiab tshuaj ntsuam xyuas tshwj xeeb, thiab lwm yam. .
Lub tshuab hluav taws xob piezoelectric ultrasonic siv lub hauv paus ntsiab lus ntawm kev siv hluav taws xob rov qab piezoelectric los hloov kev co rau hauv kev vibration siab, thiab tom qab ntawd tsim cov nthwv dej ultrasonic. Thaum qhov zaus ntawm qhov sib hloov ua haujlwm voltage yog sib npaug rau qhov resonance zaus ntawm cov khoom piezoelectric, nws yuav ua rau resonance, thiab ultrasonic yoj tsim nyob rau lub sijhawm no yog qhov muaj zog tshaj plaws. Lub piezoelectric ultrasonic sensor tuaj yeem tsim cov zaus ultrasonic nthwv dej ntawm kaum ntawm kilohertz mus rau kaum ntawm megahertz, thiab nws lub suab siv zog tuaj yeem ncav cuag kaum tawm watts ib cubic centimeter.
Cov qauv tseem ceeb ntawm cov khoom siv piezoelectric ultrasonic sensor yog tsim los ntawm piezoelectric wafer, nqus thaiv (damping block), thiab cov yeeb yaj kiab tiv thaiv. Piezoelectric wafers feem ntau yog disc-puab, thiab ultrasonic zaus yog inversely proportional rau nws thickness. Ob sab ntawm lub piezoelectric nti yog plated nrog ib txheej nyiaj raws li ib tug conductive ncej, sab hauv qab yog grounded, thiab sab saum toj yog coj mus rau lub transformer grounding hlau. Txhawm rau kom zoo dua tiv thaiv kev sib cuag ncaj qha ntawm lub sensor thiab DUT thiab kev puas tsuaj rau piezoelectric nti, ib zaj duab xis tiv thaiv yog sib koom ua ke hauv qab piezoelectric nti. Cov nyhuv ntawm qhov nqus thaiv yog txo qhov zoo ntawm cov khoom siv kho tshuab ntawm piezoelectric nti thiab nqus lub zog kinetic ntawm ultrasonic yoj.
Lub piezoelectric ultrasonic receiver ua haujlwm los ntawm kev siv lub hauv paus ntsiab lus ntawm qhov zoo piezoelectric nyhuv. Thaum ultrasonic tsis ua rau lub piezoelectric wafer ua rau lub wafer nthuav thiab cog lus, tsub nqi ntawm opposite polarity yog generated ntawm ob qhov chaw ntawm lub wafer. Cov nqi no tau hloov mus rau hauv qhov hluav taws xob thiab xa mus rau qhov ntsuas ntsuas hluav taws xob tom qab kev nthuav dav, thiab thaum kawg kaw lossis tso tawm. Cov qauv ntawm lub piezoelectric ultrasonic receiver yog ib qho zoo ib yam li lub tshuab hluav taws xob ultrasonic, thiab qee zaum tib lub sensor yog siv los ua ob lub tshuab hluav taws xob thiab lub receiver.
Lub ntsiab kev ua tau zoo ntawm ultrasonic sensor muaj xws li:
(1) Kev khiav hauj lwm zaus: Kev khiav hauj lwm zaus yog resonance zaus ntawm piezoelectric wafer. Thaum qhov zaus ntawm AC voltage thov rau nws ob qhov kawg yog sib npaug rau cov zaus resonance ntawm cov nti, lub zog tso zis yog qhov siab tshaj plaws thiab qhov rhiab heev yog qhov siab tshaj plaws.
(2) Ua haujlwm kub: Vim tias Curie point ntawm piezoelectric cov ntaub ntawv feem ntau kuj siab, tshwj xeeb tshaj yog thaum lub ultrasonic sojntsuam siv rau kev kuaj mob siv tsis muaj zog, qhov kub thiab txias ua hauj lwm kuj tsawg, thiab nws muaj peev xwm ua hauj lwm rau lub sij hawm ntev tsis ua hauj lwm. Qhov kub ntawm kev kho mob ultrasound sojntsuam yog qhov siab thiab yuav tsum tau cais cov khoom siv tub yees.
(3) rhiab heev: feem ntau yog nyob ntawm kev tsim wafer nws tus kheej. Lub electromechanical coupling coefficient yog loj thiab rhiab heev; ntawm qhov tsis sib xws, qhov rhiab heev yog tsawg.
Cov txheej txheem ua haujlwm ntawm ultrasonic sensors:
Ultrasonic sensors tuaj yeem muab faib ua piezoelectric, magnetostrictive, electromagnetic, thiab lwm yam raws li lawv cov qauv kev ua haujlwm. Hom piezoelectric yog feem ntau siv.
