{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T07:27:50Z","timestamp":1775806070591,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2019,3,1]],"date-time":"2019-03-01T00:00:00Z","timestamp":1551398400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Minimally invasive medical devices can greatly benefit from Narrow Band Imaging (NBI) diagnostic capabilities, as different wavelengths allow penetration of distinct layers of the gastrointestinal tract mucosa, improving diagnostic accuracy and targeting different pathologies. An important performance parameter is the light intensity at a given power consumption of the medical device. A method to increase the illumination intensity in the NBI diagnostic technique was developed and applied to minimally invasive medical devices (e.g., endoscopic capsules), without increasing the size and power consumption of such instruments. Endoscopic capsules are generally equipped with light-emitting diodes (LEDs) operating in the RGB (red, green, and blue) visible light spectrum. A polydimethylsiloxane (PDMS) \u00b5-lens was designed for a maximum light intensity at the target area of interest when placed on top of the LEDs. The PDMS \u00b5-lens was fabricated using a low-cost hanging droplet method. Experiments reveal an increased illumination intensity by a factor of 1.21 for both the blue and green LEDs and 1.18 for the red LED. These promising results can increase the resolution of NBI in endoscopic capsules, which can contribute to early gastric lesions diagnosis.<\/jats:p>","DOI":"10.3390\/s19051057","type":"journal-article","created":{"date-parts":[[2019,3,4]],"date-time":"2019-03-04T05:45:36Z","timestamp":1551678336000},"page":"1057","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["PDMS Microlenses for Focusing Light in Narrow Band Imaging Diagnostics"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3891-4284","authenticated-orcid":false,"given":"Adriana C.","family":"Costa","sequence":"first","affiliation":[{"name":"Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Institute of Applied Micro-Nano Science and Technology\u2014IAMNST, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan\u2019an District, Chongqing 400067, China"},{"name":"CMEMS-UMinho, Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6061-320X","authenticated-orcid":false,"given":"Sara","family":"Pimenta","sequence":"additional","affiliation":[{"name":"CMEMS-UMinho, Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1454-2778","authenticated-orcid":false,"given":"Jo\u00e3o F.","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"CMEMS-UMinho, Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manuel F.","family":"Silva","sequence":"additional","affiliation":[{"name":"CMEMS-UMinho, Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Reinoud F.","family":"Wolffenbuttel","sequence":"additional","affiliation":[{"name":"Faculty of EEMCS, TUDelft, Mekelweg 4, 2628 CD Delft, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tao","family":"Dong","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Institute of Applied Micro-Nano Science and Technology\u2014IAMNST, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan\u2019an District, Chongqing 400067, China"},{"name":"Faculty of Technology, Institute for Microsystems-IMS, Natural Sciences and Maritime Sciences, University of South-Eastern Norway (USN), Postboks 235, 3603 Kongsberg, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhaochu","family":"Yang","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Institute of Applied Micro-Nano Science and Technology\u2014IAMNST, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan\u2019an District, Chongqing 400067, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5991-1069","authenticated-orcid":false,"given":"Jos\u00e9 H.","family":"Correia","sequence":"additional","affiliation":[{"name":"Chongqing Key Laboratory of Colleges and Universities on Micro-Nano Systems Technology and Smart Transducing, Chongqing Engineering Laboratory for Detection, Institute of Applied Micro-Nano Science and Technology\u2014IAMNST, Control and Integrated System, National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Nan\u2019an District, Chongqing 400067, China"},{"name":"CMEMS-UMinho, Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1053\/tgie.2003.50001","article-title":"Narrow band imaging technique","volume":"5","author":"Mizuno","year":"2003","journal-title":"Tech. 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