NASA LogoNTRSNTRS - NASA Technical Reports ServerSearchmore_vertCollectionsAboutNewsHelpLogin Back to ResultsMicrofabricated Ice-Detection SensorKnowledge of ice conditions on important aircraft lift and control surfaces is critical for safe operation. These conditions can be determined with conventional ice-detection sensors, but these sensors are often expensive, require elaborate installation procedures, and interrupt the airflow. A micromachined, silicon-based, flush-mounted sensor which generates no internal heat has been designed, batch fabricated, packaged, and tested. The sensor is capable of distinguishing between an ice-covered and a clean surface. It employs a bulk micromachined wafer with a 7 micrometer-thick, boron-doped, silicon diaphragm which serves as one plate of a parallel-plate capacitor. This is bonded to a second silicon wafer which contains the fixed electrodes, one to drive the diaphragm by application of a voltage, the other to measure the deflection by a change in capacitance. The diaphragm sizes ranged from 1x1 mm to 3x3 mm, and the gap between parallel-plate capacitors is 2 micrometers. A 200 V d.c. was applied to the driving electrode which caused the capacitance to increase approximately 0.6pf, from a nominal capacitance of 0.6pf, when the surface was ice free. After the sensor was cooled below the freezing point of water, the same voltage range was applied to the drive electrode. The capacitance increased by the same amount. Then a drop of water was placed over the diaphragm and allowed to freeze. This created an approximately 2mm-thick ice layer. The applied 200V d.c. produced no change in capacitance, confirming that the diaphragm was locked to the ice layer. Since the sensor uses capacitive actuation, it uses very little power and is an ideal candidate for inclusion in a wireless sensing system.Document ID19970025167Acquisition SourceLegacy CDMSDocument TypeConference PaperAuthorsDeAnna, Russell G.*(Army Research Lab. Cleveland, OH United States)*Mehregany, Mehran*(Case Western Reserve Univ. Cleveland, OH United States)*Roy, Shuvo*(Case Western Reserve Univ. Cleveland, OH United States)*Zakar, Eugene*(Army Research Lab. Fort Monmouth, NJ United States)*Date AcquiredSeptember 6, 2013Publication DateJune 1, 1997Subject CategoryAircraft InstrumentationReport/Patent NumberE-10690NASA-TM-107432NAS 1.15:107432ARL-TR-1355Meeting InformationMeeting: Smart Structures and MaterialsLocation: San Diego, CACountry: United StatesStart Date: March 2, 1997End Date: March 6, 1997Sponsors:International Society for Optical EngineeringAccession Number97N24790Funding Number(s)PROJECT: RTOP 523-26-13PROJECT: DA Proj. 1L1-61102-AH-45CONTRACT_GRANT: DAAL03-91-C-0034CONTRACT_GRANT: DAAH04-95-10097Distribution LimitsPublicCopyrightWork of the US Gov. Public Use Permitted.Available DownloadsNameType19970025167.pdfSTIcloud_downloadcontent_copyvisibilityRelated RecordsThere are no records associated with this record.visibility_offNo Preview Available
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