Comprehensive Study on the Transmitted and Reflected Light Through the Phosphor Layer in Light-Emitting Diode Packages

2013 ◽  
Vol 9 (6) ◽  
pp. 447-452 ◽  
Author(s):  
Run Hu ◽  
Huai Zheng ◽  
Jinyan Hu ◽  
Xiaobing Luo
Keyword(s):  
Light Emitting Diode ◽  
Phosphor Layer ◽  
Light Emitting ◽  
Reflected Light ◽  
Comprehensive Study

Reduction of Reflected Light On Fluorescence Emission for Indocyanine Green

2021 ◽  
Author(s):  
So Yoon Kwon ◽  
Ki-Cheol Yoon ◽  
Kwang Gi Kim
Keyword(s):  
Blood Vessel ◽  
Indocyanine Green ◽  
Blood Vessels ◽  
Light Emitting Diode ◽  
Polarized Light ◽  
Fluorescence Emission ◽  
Light Reflection ◽  
Light Emitting ◽  
Surgical Microscope ◽  
Reflected Light

Abstract Inside the brain tumor, the blood vessels are intricately composed, and the tumors and blood vessels are similar in color. Therefore, when observing tumors and blood vessels with the naked eye or a surgical microscope, it is difficult to distinguish between tumors and blood vessels. Fluorescence staining with indocyanine green (ICG) is performed to distinguish between brain tumors and blood vessels using a surgical microscope. However, when observing the blood circulation state of a tumor or blood vessel through a surgical microscope, light reflection occurs from the camera. In the process of observing the state of the blood vessel, due to the occurrence of light reflection, an obstruction phenomenon in which the observation field is blocked by the blood vessel of the object to be observed occurs. Therefore, it is difficult to diagnose the vascular condition. In this experiment, the 780nm light-emitting diode (LED) was irradiated to the ICG phantom, and then, when the fluorescence expression image was observed, the polarizing filter such as circular polarized light (CPL) filter and linear polarized light (LPL) filter were inserted into the camera and the reflected light was reduced. Therefore, it is possible to reduce the reflected light from the fluorescence expression image by using a polarizing filter, and it is expected to be applicable to surgery and diagnostic fields of cancer such as surgery.

scholarly journals Passive Visible Light Detection of Humans

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1902 ◽  
Author(s):  
Kenneth Deprez ◽  
Sander Bastiaens ◽  
Luc Martens ◽  
Wout Joseph ◽  
David Plets
Keyword(s):  
Visible Light ◽  
Detection Rate ◽  
Detection System ◽  
Light Emitting Diode ◽  
Line Of Sight ◽  
Controlled Environment ◽  
Ambient Light ◽  
Light Emitting ◽  
Light Sensing ◽  
Reflected Light

This paper experimentally investigates passive human visible light sensing (VLS). A passive VLS system is tested consisting of one light emitting diode (LED) and one photodiode-based receiver, both ceiling-mounted. There is no line of sight between the LED and the receiver, so only reflected light can be considered. The influence of a human is investigated based on the received signal strength (RSS) values of the reflections of ambient light at the photodiode. Depending on the situation, this influence can reach up to ± 50 % . The experimental results show the influence of three various clothing colors, four different walking directions and four different layouts. Based on the obtained results, a human pass-by detection system is proposed and tested. The system achieves a detection rate of 100% in a controlled environment for 21 experiments. For a realistic corridor experiment, the system keeps its detection rate of 100% for 19 experiments.

scholarly journals Earable POCER: Development of a Point-of-Care Ear Sensor for Respiratory Rate Measurement

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3020 ◽  
Author(s):  
Kazuhiro Taniguchi ◽  
Atsushi Nishikawa
Keyword(s):  
Respiratory Rate ◽  
Light Emitting Diode ◽  
Point Of Care ◽  
Respiratory Frequency ◽  
Infrared Light ◽  
Rate Measurement ◽  
Ear Canal ◽  
Measuring Device ◽  
Light Emitting ◽  
Reflected Light

We have carried out research and development on an earphone-type respiratory rate measuring device, earable POCER. The name earable POCER is a combination of “earable”, which is a word coined from “wearable” and “ear”, and “POCER”, which is an acronym for “point-of-care ear sensor for respiratory rate measurement”. The earable POCER calculates respiratory frequency, based on the measurement values over one minute, through the simple attachment of an ear sensor to one ear of the measured subject and displays these on a tablet terminal. The earable POCER irradiates infrared light using a light-emitting diode (LED) loaded on an ear sensor to the epidermis within the ear canal and, by receiving that reflected light with a phototransistor, it measures movement of the ear canal based on respiration. In an evaluation experiment, eight healthy subjects first breathed through the nose 12 times per minute, then 16 times per minute, and finally 20 times per minute, in accordance with the flashing of a timing instruction LED. The results of these evaluation tests showed that the accuracy of the respiratory frequency was 100% for nose breathing 12 times per minute, 93.8% at 16 times, and 93.8% at 20 times.

scholarly journals COLORIMETRIC MEASUREMENTS OF COCOA BEANS (Theobroma cacao)

2013 ◽  
Vol 3 (2) ◽  
pp. 52
Author(s):  
Charles C.E. Meulemans ◽  
Untung Surapati T. ◽  
Ardin Tjatjo
Keyword(s):  
Diffuse Reflection ◽  
Electronic Device ◽  
Light Emitting Diode ◽  
Red Light ◽  
Cocoa Beans ◽  
Silicon Photodiode ◽  
Light Emitting ◽  
Reflected Light ◽  
Colorimetric Measurements

A series of studies have been carried out to develop a simple, easy to use, and affordable device to measure the colour of cocoa beans. The present paper reports the development of the device based on colorimetric principles. An electronic device which enables cocoa smallholders to give an objective “onefigure” indication of the quality of their cocoa beans was described. A sensor was constructed which contained a red light emitting diode (LED) illuminating the target and a silicon photodiode detecting the reflected light. Because of the considerable difference in colour between dried unfermented and fermented cocoa beans, the differences in diffuse reflection of red light (660 nm) could be about 20 and very easy to measure. The method was checked with a spectrophotometer in the fixed mode at 660 nm, which revealed a high correlation coefficient. The sensor was combined with a microprocessor controlled electronic device for fast measurement of cocoa beans without any calculations which automatically counts the number of measured beans and gives the resulting average reflection value.

Impact of the Phosphors on the Conformal Coating LED by Optical Simulation

2013 ◽  
Vol 834-836 ◽  
pp. 1167-1171
Author(s):  
Yu Bing Gong ◽  
Ruan Ji Tian
Keyword(s):  
Concentration Distribution ◽  
Light Emitting Diode ◽  
Luminous Flux ◽  
Color Temperature ◽  
Optical Simulation ◽  
Optical Performance ◽  
Phosphor Layer ◽  
Light Emitting ◽  
Conformal Coating ◽  
Color Uniformity

The conformal coating phosphor converted light emitting diode (LED) is one of the important high power white LED. The thickness, concentration and concentration distribution of the phosphor layer has a critical influence on the LED optical performance. Previous literature mainly focus on the luminous flux of the LED. Few are involved with the relationship between the concentration and the correlated color temperature (CCT), and angular color uniformity (ACU) of LED. Based on the ray-tracing simulation, the luminous flux, CCT and ACU affected by the phosphor thickness, concentration and concentration distribution were obtained and studied. The results provide effective references for the phosphor coating process design and optical performance analysis of conformal coating LED.

Design and Implementation of a Heart Rate Monitor

2013 ◽  
Vol 824 ◽  
pp. 145-150
Author(s):  
J.A. Igimoh ◽  
Susan Konyeha
Keyword(s):  
Heart Rate ◽  
Light Emitting Diode ◽  
Heart Beat ◽  
Activity Level ◽  
Infrared Light ◽  
Heart Rate Monitor ◽  
Light Emitting ◽  
Design And Implementation ◽  
Reflected Light ◽  
Beat Heart

A heart rate monitor measures the heart beat. Heart beat is the number of heartbeat per unit time, and is expressed as beats per minute (BPM). The measurement of heart rate is used by medical professionals to assist in the diagnosis and tracking of medical conditions amongst other applications. This paper describes the design of a heart rate monitor which measures the heart rate from the finger using an optical sensor which consists of an infrared light-emitting-diode (IR LED) and a phototransistor. The IR LED transmits an infrared light into the fingertip, and the phototransistor senses the portion of the light that is reflected back, each heartbeat slightly alters the amount of reflected infrared light that can be detected by the phototransistor. A non-inverting amplifier is used to detect this little change in the amplitude of the reflected light. The pulses are filtered to remove unwanted signals, counted by Atmega16L microcontroller, and the result is displayed on a text based LCD in beats per minute. An experiment was performed that demonstrated an increase in heart rate as the human activity level increases. Tests were performed on ten children between ages 3 and 10 years. The average heart beat per minute were between 94 and 119. Tests were also performed on ten students with increased physical activity and they were found to have average heartbeat per minute of between 98 and 111.

Synchronization of Chaotic Quantum Dot Light Emitting Diodes under Optical Feedback Effect

2020 ◽  
pp. 144-148
Keyword(s):  
Quantum Dot ◽  
Delay Time ◽  
Chaos Synchronization ◽  
Optical Feedback ◽  
Light Emitting Diode ◽  
Feedback Effect ◽  
Complete Synchronization ◽  
Light Emitting ◽  
Coupling Methods ◽  
Coupling Parameters

Chaos synchronization of delayed quantum dot light emitting diode has been studied theortetically which are coupled via the unidirectional and bidirectional. at synchronization of chaotic, The dynamics is identical with delayed optical feedback for those coupling methods. Depending on the coupling parameters and delay time the system exhibits complete synchronization, . Under proper conditions, the receiver quantum dot light emitting diode can be satisfactorily synchronized with the transmitter quantum dot light emitting diode due to the optical feedback effect.

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