Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-05-30T13:57:02Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação versão impressão 11.07.16.pdf: 2713868 bytes, checksum: 1b43ccd8bfdd9e87e9ee0dc36497b916 (MD5) / Made available in DSpace on 2017-05-30T13:57:02Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação versão impressão 11.07.16.pdf: 2713868 bytes, checksum: 1b43ccd8bfdd9e87e9ee0dc36497b916 (MD5) Previous issue date: 2016-02-29 / O uso de ventilação artificial é indicado para indivíduos que apresentem, insuficiência ou falência respiratória, traumatismo crânio encefálico ou pacientes politraumatizados. As unidades de terapia intensiva (UTIs) são ambientes destinados ao atendimento de pacientes graves, com potencial risco de morte, que necessitam de atendimento ininterrupto, caracterizadas, muitas vezes, como um ambiente relacionado ao sofrimento e a morte. Sabe-se que nessas unidades é comum encontrar pacientes que necessitam de suporte ventilatório mecânico invasivo através de prótese traqueal. A pesquisa deve como objetivo desenvolver um equipamento específico para aferir e corrigir a pressão do balonete do tubo endotraqueal ou cânula de traqueostomia, e verificar o nível de conhecimento dos profissionais de saúde referente a pressão do balonete externo do tubo ou cânula traqueal. Trata-se de um estudo experimental, realizado no ano de 2015 no laboratório de instrumentação biomédica do Departamento de Engenharia Biomédica da Universidade Federal de Pernambuco (UFPE). O passo inicial para o desenvolvimento do equipamento foi a escolha do sensor de pressão de baixa intensidade, cuja a função primordial do sensor de pressão é transformar uma grandeza fisiológica (pressão) em uma grandeza elétrica (tensão). O equipamento desenvolvido é capaz de monitorar a pressão do cuff, em tempo real e de forma continua. O sistema de alarme sonoro e visual com três LEDs, cada uma com finalidades diferentes, sendo a LED verde responsável em informar que os valores estão dentro dos normais, a LED amarela indica que o valor da pressão se encontra fora dos limites máximo e mínimo estabelecidos como referência e a LED vermelha indicando pressão nula do cuff. O dispositivo criado nesta pesquisa pode monitorar de forma continua a pressão do cuff, e em tempo real sinalizar aos profissionais das UTIs que os valores pressóricos se encontram fora dos limites estabelecidos pelo profissional de saúde. A maioria dos profissionais das duas UTI utilizam técnica de mensuração da pressão do cuff de forma subjetiva com a palpação digital, ao mesmo tempo que realizam o ajuste de forma errada com a utilização da seringa, sem ter a precisão de ter corrigido a pressão para os valores correto / The use of artificial ventilation is indicated for individuals who have, failure or respiratory failure, cranial trauma or polytrauma patients. Intensive care units (ICUs) are environments used in the treatment of critically ill patients with potentially lifethreatening, which require uninterrupted service, characterized often as a related suffering and death environment. It is known that these units is common to find patients requiring invasive mechanical ventilation through tracheal prosthesis. Research should aim to develop specific equipment to measure and correct the pressure of the cuff of the endotracheal tube or tracheostomy tube, and check the level of knowledge of health professionals concerning the external pressure cuff tube or tracheal cannula. This is an experimental study carried out in 2015 in biomedical instrumentation laboratory of the Department of Biomedical Engineering at the Federal University of Pernambuco (UFPE). The initial step in the development of the equipment was the choice of low-level pressure sensor, whose primary function of the pressure sensor is to turn a physiological variable (pressure) into an electrical magnitude (voltage). The equipment developed is able to monitor the cuff pressure in real time and continuously. The audible and visual alarm system with three LEDs, each with different purposes, and the green LED charge to report that the values are within normal, the yellow LED indicates that the pressure value is outside the maximum and minimum limits as a reference and the red LED indicates zero pressure cuff. The device created in this research can monitor continuously the pressure of the cuff, and real-time signal to the ICU professionals that blood pressure values are outside the limits set by health professional. Most practitioners of the two ICUs use cuff pressure measurement technique subjectively by digital palpation while performing adjustment in the wrong way with the use of the syringe without having to precision have fixed pressure for correct values.

Lab-on-chip systems have been developed for various applications like point of care diagnostics and compact imaging systems. Compact, on-chip imaging systems face a challenge in the integration of multicolor light sources on-chip. This is because of the unavailability of compact, individually addressable, multicolor light sources on a single planar substrate. Colloidal Quantum Dot based Light Emitting Diodes (QDLEDs), which have found wide appeal, due to their unique properties like their tunable and narrow emission bandwidth and easy fabrication, are ideal for lab-on-chip integration. Among different types of QDLED structures implemented, inorganic QDLEDs have shown great promise. We have demonstrated designs and fabrication strategies for creating QDLEDs with enhanced performance. In particular: (I) We introduce a sandwich structure with a spin coated inorganic hole transporting layer of nickel oxide underlying the QD layer and with a spin coated zinc oxide electron transporting layer, with patterning of anode and cathode on the substrate. Compared to the use of sputtered thin films, solution processed charge transporting layers (CTLs) improve robustness of the device, as crystalline ZnO shows low CB and VB edge energy levels, efficiently suppressing hole leakage current resulting in LEDs with longer lifetimes. We also use Atomic Layer Deposition to deposit an additional hole injecting layer to protect the QDs from direct contact with the anode. With this device design, we demonstrate a working lifetime of more than 12 hours and a shelf-life of more than 240 days for the devices. Our solution based process is applicable to micro-contact printed and also spin-coated QD films. QDLEDs with spin-coated CTLs show a lifetime increase of more than three orders of magnitude compared to devices made using sputtered CTLs. (II) We implement strategies of the enhancement of light extraction from the fabricated QDLEDs. We discuss the integration of a two dimensional grating structure based on a metal-dielectric-metal plasmonic waveguide with the metal electrode of a QDLED, with the aim of enhancing the light intensity by resonant suppression of transmitted light. The grating structure reflects the light coupled with the metal electrode in the QDLED and we found an increase of 34.72% in the electroluminescence intensity from the area of the pattern and an increase of 32.63% from photoluminescence of QDs deposited on a metal surface. (III) We demonstrate the capability of our fabricated devices as a light source by measuring intensity across stained cells with QDLEDs of two different wavelengths and show the correlation as expected with the absorption profile of the fluorescent dye. We measure the absorption from the biological samples using QDLEDs fabricated with various design modifications, as a quantification of the improvements in device performance, directly affecting to our target application. / text

Photocatalytic treatment has the potential to become a cost effective method of organic contaminant removal from water. Photocatalytic materials are semiconductors that enhance chemical reactions such as the breakdown of organic molecules in the presence of light. One of the most studied photocatalysts for water purification is titanium dioxide (TiO2). Variations in the composition of photocatalysts can affect the outcome of the experiments, the detection of the change in behaviour of the photocatalyst is of significant scientific interest. It requires minimisation of the impact of all other factors affecting the photocatalytic process, such as temperature, light intensity, wavelength and uniformity. Repeatability of the experiments is also affected by these factors. If their impact is not considered and addressed the outcome of multiple seemingly identical experiments with a single sample of the photocatalyst will produce different results. Light is one of the most important factors in a photocatalytic process. The undoped TiO2 has a sharp drop in its light absorbtion characteristics between UV and visible spectral regions. It is theregion of the spectrum where most efficient UV LEDs radiate. As the characteristics of the light produced by LEDs are temperature dependent, heat management is important in achieving light with stable characteristics and prolonged lifetime of the LEDs. One of the contributions of this thesis is a novel method of not only stabilisation of the LED radiation parameters, namely optical output power and wavelength, but also the independent control of these parameters. The importance of LED calibration is also a significant contribution as commercial LEDs have dierent radiation parameters between devices. Possibility of independent control of optical power and wavelength of the LEDs has allowed to demonstrate the importance of radiant flux (total spectral power) over the peak spectral flux (power of a single wavelength component) for TiO2 activation, which is another significant contribution of this work. Uniformity of the produced light is another factor that needs to be addressed when a light source for the photocatalytic experimentation is designed. Non-uniform light distribution in a photocatalytic reactor will result in bright spot formation that will affect the overall performance of the photocatalytic sample. This together with the temperature control of the photocatalyst and the water sample are key issues that need to be addressed for achieving ecient and repeatable experimentation outcomes. Photocatalytic reactors developed from simulation to the working prototypes and tested during the work described in this thesis address the problem of light distribution uniformity. They have been designed to remove as many sources of uncertainty usually present in photocatalytic reactors as possible, such as for example temperature stability of the liquid sample, dierent sizes or of the photocatalytic samples and same volume of the liquid sample. As such, these novel reactors together with LED light sources provide a contribution of having a potential of becoming a photocatalytic experimentation standard for achieving the repeatable and comparable results.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Este trabalho apresenta o estudo, o projeto e a implementaÃÃo de um driver trifÃsico para diodos emissores de luz (LEDs) baseado num conversor com capacitor chaveado (SC â Switched Capacitor), tambÃm conhecido como charge-pump. Uma luminÃria LED com a tecnologia Chip-on-Board (COB), que proporciona uma elevada densidade de potÃncia, à utilizada como carga. Assim como os LEDs, os drivers destes dispositivos devem apresentar uma longa vida Ãtil e um elevado rendimento. A vida Ãtil dos drivers para LEDs à geralmente limitada pelo uso de capacitores eletrolÃticos convencionais. Estes dispositivos apresentam uma vida Ãtil incompatÃvel com a dos LEDs e, por isso, nÃo devem ser utilizados nos seus drivers. AlÃm disso, os drivers para LEDs devem proporcionar uma baixa ondulaÃÃo de corrente nos LEDs, garantindo um baixo flicker percentual e evitando danos à saÃde humana. Diante destes problemas, o conversor trifÃsico SC proposto nÃo utiliza capacitores eletrolÃticos, o que eleva a expectativa de vida Ãtil do driver. O conversor emite um baixo flicker percentual e à capaz de estabilizar a corrente de saÃda sem a necessidade de um controle de malha fechada, o que pode reduzir os custos de projeto. A topologia permite a dimerizaÃÃo dos LEDs atravÃs da variaÃÃo da frequÃncia de comutaÃÃo. Resultados experimentais de um protÃtipo de 216 W sÃo analisados e discutidos para validaÃÃo da proposta. Em condiÃÃes nominais, o conversor apresentou um rendimento global de 91,5%, um fator de potÃncia acima de 0,99 e uma distorÃÃo harmÃnica menor que 5% nas trÃs fases, obedecendo as Classes A e C da norma IEC 61000-3-2:2014. AlÃm disso, foi obtida uma ondulaÃÃo de corrente de alta frequÃncia igual a 16,97% e um flicker percentual de 4,97%, estando de acordo com as recomendaÃÃes da IEEE. A dimerizaÃÃo dos LEDs permitiu a reduÃÃo da potÃncia de saÃda em atà 50%, com rendimento prÃximo a 91%, fator de potÃncia acima de 0,97, distorÃÃo harmÃnica total inferior a 6% para as trÃs fases e flicker percentual menor que 7% para toda a faixa de potÃncia. / This paper presents the study, design and implementation of a three-phase light-emitting diode (LED) driver based on a switched capacitor (SC) converter, also known as charge-pump. A LED lamp with Chip-On-Board (COB) technology, which provides a high power density, is used as load. As the LEDs, drivers of these devices must have a high efficiency and a long useful lifetime, which is usually limited by the use of conventional electrolytic capacitors. These devices have an incompatible lifetime with LEDs and, therefore, they should not be used in their drivers. In addition, the LED drivers should provide a low ripple current in LEDs, which can provide the emission of a low percent flicker. Studies demonstrate that excessive percent flicker may cause damage to human health. Given these problems, the proposed switched capacitor LED driver does not use electrolytic capacitors, which increases the expectative of useful lifetime of the driver. It emits a low percent flicker, which reduces the risks to human health. It can stabilize the output current without the need of a closed-loop control, which may reduce design costs. It allows the LEDs dimming by varying the switching frequency. An experimental prototype rated at 216 W has been developed in order to evaluate the performance of the proposed approach, while results are properly presented and discussed. In nominal conditions, the drive presented an overall efficiency of 91.5%, a power factor greater than 0.99 and a current total harmonic distortion lower than 5% in three phases. The harmonic currents are in accordance with the limits imposed by IEC Standard 61000-3-2:2014 to class A and C equipment. Furthermore, a high frequency current ripple equal to 16.97% and a percent flicker of 4.97% was obtained, which is in accordance with IEEE recommendations. The LEDs dimming allowed the reduction of the output power up to 50%, while the efficiency remained close to 91% and the power factor remained above 0.97. In addition, the total harmonic distortion was below 6% and the percent flicker was lower than 7% for the entire dimming range.

This is a kind of image processing algorithm in order to realize a seamless video wall and improve the quality of images. / Nowadays, screens are very common in our daily life. There are several di erent kinds of screens, LCD, LED, OLED, ULED and so on. LCD screens can display high-resolution pictures while LED has advantages of low energy consumption and wider color range. This project has two goals. The rst one is to achieve a seamless display screen which consists of 9 LED backlit LCD boards. The second goal is to improve image quality, which is enabled by the combination of LED and LCD. There are two main problems that need to be solved in this project. The rst problem is brightness correction. Because of the projection method and the distance between lights and nal screen, there are di erent kinds of overlapping situations and distinct lines on screen. The other one is the combination of LED and LCD. The algorithms need to be developed to ensure that RGB LEDs and LCD panels display the same picture and to address some problems caused by the LCD module. / Thesis / Master of Applied Science (MASc)

After the invention of the high-efficiency blue light-emitting diode (LED) at the end of the twentieth century, a new generation of light-emitting devices based on III-nitrides emerged, showcasing the capabilities of this semiconductor family. Despite the current limitations in the fabrication of III-nitrides, their optical and electronic properties still place them as some of the most promising semiconductors to continue the development of optoelectronic devices. To take full advantage of the versatility offered by these materials, the fabrication of novel III-nitride-based devices demands rigorous control of all of its stages. From the initial deposition of the materials, which involves controlling the composition and size of often complex heterostructures, up to the microfabrication processing used to create a final device, any deficiency occurring will negatively impact the performance of the device. Most of the time, these deficiencies reflect in microscopic defects, hindering their detection and identification of their origin. Without such knowledge, the deficiencies cannot be fixed, stalling the improvement of the device fabrication process and, consequently, its performance. This dissertation presents a variety of methodological approaches to characterize, from a microstructural point of view, different properties of novel III-nitride-based heterostructures and devices. The characterizations include studying the structure, interface, composition, and crystalline defects of different heterostructures and evaluating the microfabrication quality of microscopic LEDs. The results of the different characterizations contributed to developing novel LED and photocatalytic devices, for example, a single-quantum-well InGaN-based red LED with a high color purity, a monolithic phosphor-free white LED, microscopic green LEDs with a size smaller than 5×5 μm$^2$, and metal oxide/GaN-based photocatalysts with improved resilience to photocorrosion. The analyses and results presented in this dissertation strongly relied on the analytical capabilities offered by transmission electron microscopy, which proved to be a convenient and versatile tool for the characterization of many aspects related to the fabrication of III-nitride-based optoelectronic devices.

Perovskites have raised interest due to their unique physical and optical properties in many fields. Adjustable bandgap, high photoluminescence quantum yield (PLQY), and a wide range of emitting colors make perovskite promising for light-emitting diodes (LEDs) devices. Up to now, too little attention has been given to understanding the growth mechanism of perovskite. Hence, establishing the growth kinetic model is a priority research focus. We explore that low temperatures could slow down the reaction rate of forming perovskite, which provides a chance for monitoring the growth kinetic of perovskite. Additionally, the low external quantum efficiency (EQE) of blue-emitting perovskites hinders their practical industrial production. Thus, another objective of this study is to investigate the effect of Mn2+/Nd3+ co-doping in blue-emitting perovskite. Finally, we achieve a blue-emitting perovskite CsPbMn1.3%Nd2.2%Br3 with a wavelength of 445 nm. This dissertation follows two case-study designs, analyzing characterization techniques (XRD, UV-visible absorption, PL, ICP) by origin and MATLAB software.

Os diodos emissores de luz (LEDs) são utilizados em vários setores da agricultura, principalmente no cultivo in vitro, por ser uma alternativa de fonte de luz mais eficiente. Além de proporcionar uma significativa economia de energia elétrica, pode também auxiliar no desenvolvimento das plantas. Algumas técnicas de cultivo in vitro tem a finalidade de conservar os recursos fitogenéticos, que são fundamentais para viabilizar o estabelecimento de bancos de germoplasma e permitir a produção comercial de plantas micropropagadas. No Brasil, essa técnica já é usada para a propagação de plantas, no entanto ainda são poucos experimentos com a presença de LEDs. O objetivo do estudo foi avaliar o desenvolvimento de plântulas de morangueiro da cultivar Camarosa conservadas in vitro, sob a ação de diferentes espectros de luz. Os explantes de morangueiro foram mantidos em tubos de ensaio contendo 10 ml de meio de cultura semi-sólido MS, acrescido de 30 g de sacarose L-1; 1,8 g L-1 de Phytagel® e 0,1 mg L-1 de IBA (ácido idolbutírico), permanecendo in vitro por 28, 56, 84, 112 e 140 dias sob os tratamentos de LEDs de cor branca, mista (70% vermelha + 30% azul), vermelha e azul, sem ocorrência de subcultivos. Em cada intervalo de tempo, foram avaliadas a altura, peso fresco, número e comprimento das raízes, número de folhas, diâmetro do caule, teores de clorofila a e b. As plântulas obtidas foram aclimatizadas por 21 dias e avaliadas a taxa de sobrevivência das plantas, expressas em porcentagem, o número de folhas, o diâmetro do caule e a altura das plantas. O uso de LEDs de cor vermelha e mista contribuíram para o desenvolvimento das plântulas, já a luz azul reduziu o desenvolvimento das plântulas. Em relação aos pigmentos fotossintéticos, a utilização de LEDs não teve interferência em nenhum tratamento sob as plântulas. Na aclimatização, as plântulas sob efeitos das luzes vermelha e mista, tiveram um melhor resultado de sobrevivência em até três meses de conservação sem subcultivos. / Light emitting diodes (LEDs) are used in many agriculture sectors, especially in vitro cultivation, because it is a more efficient light source alternative. In addition to providing significant energy savings, it can also help in the development of plants. Some techniques of in vitro cultivation have the purpose of conserving plant genetic resources, which are fundamental to enable the establishment of germplasm banks and allow the commercial production of micropropagated plants. In Brazil, this technique is already used for the propagation of plants, however there are still few experiments with the presence of LEDs. The objective of the study was to evaluate the development of strawberry cv. Camarosa conserved in vitro, under the effect of different light spectra. The strawberry explants were kept in test tubes containing 10 ml of MS semi-solid culture medium, plus 30 g of sucrose L-1; 1.8 g L-1 of Phytagel® and 0.1 mg L-1 of IBA (idolbutyric acid), remaining in vitro for 28, 56, 84, 112 and 140 days under the treatments of mixed white LEDs (70% red + 30% blue), red and blue, without subculture interference. At each interval, height, fresh weight, number and length of roots, number of leaves, stem diameter, chlorophyll a and b contents were evaluated. The seedlings obtained were acclimatized for 21 days and evaluated the survival rate of the plants, expressed as percentage, number of leaves, stem diameter and height of plants. The use of red and mixed color LEDs contributed to the development of the seedlings, while the blue light reduced the development of the seedlings. In relation to the photosynthetic pigments, the use of LEDs did not interfere in any treatment under the seedlings. In acclimatization, the seedlings under the effects of red and mixed lights, had a better survival result in up to three months of conservation without subcultures.

Durante este trabalho foram sintetizados e caracterizados três derivados dialcoxilados do poli(p-fenileno-vinileno) que diferem entre si pelo tamanho de uma das cadeias laterais: o poli(2-metoxi-5-hexiloxi-p-fenileno-vinileno), MH-PPV, o poli(2-metoxi-5-dodecoxi-p-fenileno-vinileno), MD-PPV e o poli(2-metoxi-5-hexadecoxi- p-fenileno-vinileno), MHd-PPV. Esses polímeros apresentam propriedades eletroluminescentes e podem ser utilizados em dispositivos emissores de luz. A síntese consiste de três etapas: síntese do éter aromático; bisclorometilação do éter aromático, gerando o monômero; e polimerização. A maior diferença no processo de síntese foi observada na obtenção do monômero, sendo necessário um maior excesso de reagente e maiores tempos de reação para a obtenção do monômero do MD-PPV e do MHd-PPV do que para o MH-PPV. Todos os produtos foram caracterizados principalmente por espectroscopia na região do infravermelho, FTIR, e por Ressonância Magnética Nuclear de próton e carbono 13. A estrutura química dos polímeros foi confirmada por FTIR e as massas moleculares foram determinadas por Cromatografia de Exclusão por Tamanho, revelando uma alta polidispersividade e valores de massa molecular ponderal média (Mw) da ordem de 105. A análise térmica revelou valores de temperatura de transição vítrea, Tg e amolecimento, Ts, acima de 100oC, e ainda temperaturas de decomposição acima de 400oC para os três polímeros. O MHd-PPV, apresentou, além da Tg, uma transição em tomo de 50oC que pode estar relacionada à fusão das cadeias laterais. Filmes dos três polímeros preparados a partir de diferentes solventes apresentaram diferentes morfologias, observadas por Microscopia de Força Atômica, posições de máxima absorção (500-520 nm) e emissão (585-600 nrn) com pequenas variações e processos de fotodegradação com diferentes características, em função do solvente utilizado. Assim, as diferentes cadeias laterais apresentaram efeitos principalmente sobre características como temperatura de transição vítrea e morfologia dos filmes poliméricos, e, em consequência desta última, sobre o formato dos espectros de emissão e sobre o processo de degradação / In this work, three dialkoxy derivatives of poly(p-phenylenevinylene),which differs from each other by the size of the side chain, were synthesized and characterized: the poly(2-methoxy-5-hexyloxy-p-phenylenevinylene), MH-PPV, the poly(2-methoxy-5-dodecoxy-p-phenylene-vinylene), MD-PPV and the poly(2-methoxy- 5-hexadecoxi-p-phenylene-vinyleno), MHd-PPV. These polymers have electroluminescent properties and can be used in light emitting devices. The synthesis consists in three steps: synthesis of aromatic ether, bischloromethylation of the ether yielding the monomer, and polymerization. The major difference regarding the synthesis processes lies on the monomer synthesis. A larger excess of reagents and longer reaction times were necessary to obtain the MD-PPV and MHd-PPV than that used to obtain the MH-PPV. All the products of the two first steps were characterized mainly by FTIR and NMR (proton and carbon 13). The chemical structures of the polymers were confirmed by FTIR and the molar masses determined by characterized by Size Exclusion Chromatography, revealing a high polydispersity and values of mean mass molecular weight (Mw) around 105. The thermal analysis presented values of glass transition temperatures, Tg, and softening, Ts, above 100 oC, and decomposition temperatures above 400oC for the three polymers. The MHd-PPV, presented, besides the Tg, a transition in 50oC, which may be related to the melting of the side chain. Films of the three polymers prepared from different solvents presented different morphologies, as observed by Atomic Force Microsocopy, slightly different absorptions (500-520 nm) and emission (585-600 nm) maxima and different photo-degradation processes depending on the solvent used to prepare the films. Therefore, the different size of the side chain presented effects mainly on characteristics as thermal transitions and film morphologies, and, in consequence of the late, on the shape of the emission and on the degradation properties

Esta pesquisa traz à tona, de forma interdisciplinar, estudos realizados e em andamento nas áreas de medicina, fisiologia, biologia, saúde pública, psicologia, engenharia e arquitetura, para investigar algumas alterações fisiológicas provocadas pela luz produzida pelos LEDs e, a partir da análise dos dados coletados, estabelecer em caráter preliminar novos parâmetros a serem considerados e aplicados ao projeto luminotécnico residencial que utiliza LEDs como fonte de luz. Desenvolvemos um protocolo para coletar os dados e comparar, para cada sujeito, o comportamento das variáveis entre dois períodos distintos, com a duração de 3 dias cada: um período em que, à noite, os sujeitos utilizaram óculos bloqueadores de luz azul (Período BB) e outro em que, também à noite, permaneceram expostos à iluminação artificial de LEDs em seus ambientes de maior permanência, previamente por eles definidos (Período LED). Verificamos a carga excretada de 6-sulfatoximelatonina na urina noturna de 12 horas (n=10), as variações de temperatura corporal (n=9) e as variáveis produzidas por meio da actimetria (n=10). Confrontamos estes dados com a literatura atual e com as características dos respectivos sistemas de iluminação. Do grupo de 10 sujeitos, 7 apresentaram redução da carga excretada de 6-sulfatoximelatonina do Período BB para o Período LED. A análise de temperatura corporal do grupo de 9 sujeitos, revelou que 7 deles apresentaram atraso de fase do respectivo ritmo do Período BB para o Período LED. A actimetria não revelou diferenças significativas entre os períodos. Porém, para o grupo que apresentou redução da carga excretada de 6-sulfatoximelatonina do Período BB para o Período LED, o L5 (período de 5 horas de menor atividade motora) apresentou um atraso de fase médio de 15 minutos. Os resultados desta pesquisa comprovam, pela primeira vez por meio de um estudo de campo, que os LEDs utilizados nos sistemas de iluminação artificial do ambiente residencial, possuem a capacidade de causar impactos deletérios na saúde dos usuários. / This research uses interdisciplinary ongoing studies in medicine, physiology, biology, public health, psychology, engineering and architecture, to investigate some physiological changes caused by the light emitted by LEDs and, based on the results, establish in a preliminary way, new parameters to be considered and applied to residential lighting projects using LEDs as a light source. We developed a protocol to collect some data and we compared, for each subject, the values between two distinct periods of 3 days each: the BB Period, where subjects wore blue-light blocking glasses at night, and the LED Period, where they were exposed to their room\'s LED lights at night. We verified the excreted load of 6-sulfatoxymelatonin in the 12-hour overnight urine (n=10), changes in pheripheral body temperature (n=9), and the variables of actimetry (n=10). We analyzed these data using information provided by the current literature and crossed these data with the characteristics of the lighting systems. Within the group of 10 subjects, 7 had a reduction in the excreted load of 6-sulfatoxymelatonin from the BB Period to the LED Period. The analysis of body temperature from the group of 9 subjects revealed that 7 of them showed acrophase phase delay from the BB Period to the LED Period. Actimetry did not reveal significant differences between these periods. However, for the group which showed a reduction in the excreted load of 6-sulfatoxymelatonin from the BB Period to the LED Period, the L5 (least active 5-hour period) presented, in average, a 15-minute phase delay. The results of this research prove, for the first time through a field study, that the LEDs used in residential lighting systems fave the capacity to cause deleterious impacts on users\' health.