Encontrados 38 documentos, a visualizar página 1 de 4
A planar thermoelectric power generator for integration in wearable microsystems
Carmo, J. P.; Gonçalves, L. M.; Wolffenbuttel, R. F.; Correia, J. H.A technique for IC-compatible fabrication of a planar (in-plane) thermoelectric (TE) power generator using a thermopile composed of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) thin-films is presented. The research demonstrates that the thermal co-evaporation of bismuth/antimony (Bi/Sb) and telluride (Te) is the most suitable deposition technique. The measurements showed TE performan...
Lab-on-a-chip for biological fluids analysis by spetrophotometry
Minas, Graça; Wolffenbuttel, R. F.; Correia, J. H.The healthcare sector is nowadays one of the most dynamic and where the novelty is a strategic and operational imperative. The possibility of increase the quantity and quality of clinical analysis, performed with instantaneous results and outside the clinical laboratories, contributes to a better quality in the health care services and also a better efficiency in the clinical and administrative processes [1]. T...
Comparison between bulk micromachined and CMOS x-ray detectors
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper compares two x-ray detectors fabricated using two different technologies: one is based on a bulk micromachined silicon photodetector and the other is based on a standard CMOS photodetector. The working principle of the two detectors is similar: a scintillating layer of CsI:Tl is placed above the photodetector, so the x-rays are first converted into visible light (560nm) which is then converted into a...
CMOS x-rays detector array based on scintillating light guides
Rocha, J. G.; Ramos, N. F.; Lanceros-Méndez, S.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a pixel imaging array consisting in 400µm x 400µm photodiodes fabricated in CMOS technology. An array of scintillating CsI:Tl crystals is placed above the photodiodes. These crystals are encapsulated in aluminum walls, forming a light path that guides the visible light produced by the scintillating crystal into the photodiodes. In This way, the x-ray energy is first converted into visible l...
Biological microsystem for measuring uric acid in biological fluids
Minas, Graça; Martins, Júlio S.; Ribeiro, J. C.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a biological microsystem (bio-system) for measuring uric acid concentration in serum, plasma or urine. Its operation is based on optical absorption in a well-defined part of the visible spectrum. The bio-system is composed by two dies: one is fabricated in polystyrene and contains the microchannels and the other is fabricated in a CMOS standard process and contains the photodetector and rea...
An array of fabry-perot optical-channels for biological fluids analysis
Minas, Graça; Ribeiro, J. C.; Martins, Júlio S.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a biosystem (biological system) used to measure the concentration of biochemical substances in urine, serum, plasma or cerebrospinal fluid. Rather than just one channel, it comprises 16 optical-channels that enable the measurement of the concentration of 16 different biochemical substances. An array of 16 optical filters based on Fabry-Perot thin-films optical resonators has been designed. ...
CMOS x-ray image sensor with pixel level A/D conversion
Rocha, J. G.; Ramos, N. F.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a pixel array for x-rays imaging consisting in 400 um x 400 um photodiodes fabricated in CMOS technology, with an A/D converter for each one. Above the photodiodes, an array of scintillating CsI:Tl crystals are placed. So, the x-ray energy is first converted to visible light by the scintillating crystals which is then detected by the photodiodes. The photocurrent produced by each photodiode...
Comparison between bulk micromachined and CMOS detectors for X-ray measurements
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Moreira, M. V.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper compares two x-ray detectors fabricated using two different technologies: one is based on a bulk micromachined silicon photodetector and the other is based on a standard CMOS photodetector. The working principle of the two detectors is similar: a scintillating layer of CsI:Tl is placed above the photodetector, so the x-rays are first converted into visible light (560 nm) which is then converted into ...
CMOS X-ray imager for dental radiography
Ramos, N. F.; Rocha, J. G.; Lanceros-Méndez, S.; Wolffenbuttel, R. F.; Correia, J. H.This paper describes a 64 pixels X-ray imager architecture and fabrication process. The imager is composed by a 8×8 photodiodes array, fabricated in CMOS process, and an array of wells £lled with scintillating crystals. A thick-£lm of aluminum is etched in order to achieve square wells with 500 um depth. The wells are filled with CsI:Tl scintillating crystals and placed above the photodiodes. The scintillating ...
X-ray detector based on a bulk micromachined photodiode combined with a scintil...
Rocha, J. G.; Schabmueller, C. G. J.; Ramos, N. F.; Lanceros-Méndez, S.; Costa, Manuel F. M.; Evans, A. G. R.; Wolffenbuttel, R. F.; Correia, J. H.This paper reports the design, fabrication, assembly and testing of a x-ray detector based on a bulk micromachined photodiode (BMMPD) with a cavity filled with a scintillating crystal. The x-ray photons that reach the detector are first converted to visible light by the scintillating crystal. The visible light is then detected by the BMMPD, producing an electric current with value proportional to the incident x...
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