Detection of human movement by near field imaging : development of a novel method and applications

The proportion of senior citizens is increasing, which requires more resources in the care services. The effectiveness of these services is proposed to be increased by remote monitoring of senior citizens living at home or in nursing homes. The monitoring can be performed with various types of sensors, but the solution presented here incorporates most of the functionalities found in related work in one comprehensive system. The system that was developed uses electric field sensing to detect human presence and movement. Falls and the vital functions of a fallen person can also be extracted from the signals. The sensor arrangement consists of a matrix of thin planar electrodes under the floor surface, which makes the system completely undetectable and discreet. It is not disturbed by shading or darkness and does not require a lot of computing power. Computer vision does not enjoy these advantages. Furthermore, no devices need to be worn and no batteries need to be charged, as with systems based on transponders worn by the subject. If identification is required, the system developed in this work does not rule out the use of transponders. The impedances of the electrodes are measured using a tuned transformer and a phase-sensitive detector. A signal-to-noise ratio of 37 dB has been achieved with this structure. The mean positioning error when observing people who are walking is 21 cm. Multiple people can be discriminated with a 90% certainty if the distance between them is 78 cm. The sensitivity and specificity in fall detection have been found to be 91% and 91%, respectively. The cardiac activity and respiration are clearly visible when a person lies prone or supine on the floor. A capacitive radio frequency identification (RFID) tag in a shoe was developed for person identification. The system developed here has been installed in a large nursing home. The nurses have indicated their satisfaction in a comprehensive questionnaire, which was conducted by a representative of the nurses. Positive feedback has also been obtained from a senior person living alone and from his family members

Kapasitiivisen anturin elektroniikka

Väestön ikärakenne vanhenee merkittävästi lähitulevaisuudessa. Vanhenemisen luonnollinen seuraamus on lisääntynyt terveydenhuollon tarve. Tämä merkitsee lisääntyneitä kustannuksia vanhustenhoidon alalla sekä resurssipulaa henkilökunnan ja sijoituspaikkojen osalta. Tietotekniikan avulla pystytään mahdollistamaan pitkä omaehtoinen elämä, mikä korottaa henkilön elämänlaatua ja säästää resursseja. Toteutetulla järjestelmällä pyritään automatisoimaan osa vanhenevan henkilön tarkkailusta, jolloin hoitohenkilökunnan ja kotihoitajien resurssit jakaantuvat tehokkaasti kiertokäyntien ja muiden toimien kesken. Tutkittavalla menetelmällä mitataan ihmisen aiheuttamia muutoksia lähikentässä. Mitattavan tilan lattia varustetaan kapasitiivisilla antureilla, joiden kautta kulkevaa vaihtovirtaa mitataan herkällä ilmaisuelektroniikalla. Anturimaton aktiivisista alueista tunnistetaan kaatumiselle tyypillisiä kuvioita, jolloin aloitetaan henkilön elintoimintosignaalin mittaus. Elintoimintosignaali saadaan vahvistamalla ja suodattamalla voimakkaasti perussignaalia. Toteutetulla järjestelmällä pystytään seuraamaan liikkuvan henkilön sijaintia suurella tarkkuudella, jos liikenopeus pysyy hitaana tai henkilö seisoo paikoillaan. Jos liikenopeus kasvaa, paikannustarkkuus putoaa tyydyttävälle tasolle. Elintoimintosignaalista pystytään toteamaan paikoillaan makaavan henkilön sykkeen ja hengityksen taajuus. Järjestelmä soveltuu nykyisellä toteutuksellaan hyvin henkilön liikkeen ja elintoimintojen mittaamiseen laboratorio-oloissa. Laitteisto tarvitsee jatkokehitystä, jotta pilottiasennukset olisivat mahdollisia. Jatkokehityksen tuloksena syntyvä tuote soveltuu vanhustenhoidon lisäksi kulunvalvontaan ja taloautomatiikan ohjaukseen

3D flip chip packaging of MEMS sensor

Advanced 3D packaging of a Micro Electro Mechanical Systems (MEMS) chip and a CMOS/ASIC Chip was studied. We successfully introduced redistribution process applying two spin coated polybenzoxazole (PBO) polymer layers and two metal layers on 200 mm ASIC wafer. Both MEMS and ASIC bump pad openings were set to 60 μm in diameter. Sputtering and electrochemical plating (ECP) techniques were utilized for metallization. On the Al pads of the sensor Au stud bumps were created. The redistributed ASIC pads were coated with sputtered Au on top of the ECP nickel metal layer and thus Au-Au flip chip bonding was accomplished. The MEMS sensor element in this study was capacitive pressure sensing diaphragm. The diaphragm was made of poly-Si. The pressure range tested was typical barometric range from 35 kPa to 115 kPa. The device operating temperature range from - 40 °C to + 85 °C was tested. Along with the packaging process, solder ball transfer jig was fabricated using bulk silicon wafer. It enabled transfer of eight solder balls to the Chip Scale Packaging (CSP) at one time. The solder ball landing pad was sputtered Au as well. The solder ball pad openings were 300 μm in diameter. Two different size of solder balls were used, 310 μm and 410 μm to ensure enough clearance between CSP and Printed Circuit Board (PCB). Solder balls were consisted of polymer core ball with SnAgCu (SAC) solder metal layers. Several thermo compression bondings were carried out and fine-tune solder ball connections. Functionality was verified by electrical device measurements. To improve productivity, replacement of the Au stud bumps was demonstrated using wafer level ECP to make SnAg μbumps. The plating quality attained within 1 μm height uniformity inside a bonding chip area. SEM observation showed that connection of SnAg micro bump to Au-pad metal was realized.</p