{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,8]],"date-time":"2025-11-08T22:58:40Z","timestamp":1762642720701,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2022,6,14]],"date-time":"2022-06-14T00:00:00Z","timestamp":1655164800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"New Energy and Industrial Technology Development Organization","award":["JP19H04147"],"award-info":[{"award-number":["JP19H04147"]}]},{"DOI":"10.13039\/501100001691","name":"JSPS KAKENHI","doi-asserted-by":"publisher","award":["JP19H04147"],"award-info":[{"award-number":["JP19H04147"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We propose urethane-foam-embedded silicon pressure sensors, including a stress-concentration packaging structure, for integration into a car seat to monitor the driver\u2019s cognitive state, posture, and driving behavior. The technical challenges of embedding silicon pressure sensors in urethane foam are low sensitivity due to stress dispersion of the urethane foam and non-linear sensor response caused by the non-uniform deformation of the foam. Thus, the proposed package structure includes a cover to concentrate the force applied over the urethane foam and frame to eliminate this non-linear stress because the outer edge of the cover receives large non-linear stress concentration caused by the geometric non-linearity of the uneven height of the sensor package and ground substrate. With this package structure, the pressure sensitivity of the sensors ranges from 0 to 10 kPa. The sensors also have high linearity with a root mean squared error of 0.049 N in the linear regression of the relationship between applied pressure and sensor output, and the optimal frame width is more than 2 mm. Finally, a prototype 3 \u00d7 3 sensor array included in the proposed package structure detects body movements, which will enable the development of sensor-integrated car seats.<\/jats:p>","DOI":"10.3390\/s22124495","type":"journal-article","created":{"date-parts":[[2022,6,15]],"date-time":"2022-06-15T01:39:54Z","timestamp":1655257194000},"page":"4495","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Urethane-Foam-Embedded Silicon Pressure Sensors including Stress-Concentration Packaging Structure for Driver Posture Monitoring"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6502-7819","authenticated-orcid":false,"given":"Seiichi","family":"Takamatsu","sequence":"first","affiliation":[{"name":"Department of Precision Engineering, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan"},{"name":"Graduate School of Frontier Sciences, The University of Tokyo, Kashiwano-ha 5-1-5, Kashiwa 277-8563, Japan"}]},{"given":"Suguru","family":"Sato","sequence":"additional","affiliation":[{"name":"Graduate School of Frontier Sciences, The University of Tokyo, Kashiwano-ha 5-1-5, Kashiwa 277-8563, Japan"}]},{"given":"Toshihiro","family":"Itoh","sequence":"additional","affiliation":[{"name":"Department of Precision Engineering, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan"},{"name":"Graduate School of Frontier Sciences, The University of Tokyo, Kashiwano-ha 5-1-5, Kashiwa 277-8563, Japan"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2636","DOI":"10.1073\/pnas.1513271113","article-title":"Driver crash risk factors and prevalence evaluation using naturalistic driving data","volume":"113","author":"Dingus","year":"2016","journal-title":"Proc. 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