A novel Cr3+-doped Lu2CaMg2Si3O12 garnet phosphor with broadband emission for near-infrared applications

2021 ◽  
Author(s):  
Wendong Nie ◽  
Liqin Yao ◽  
Guang Chen ◽  
Shihao Wu ◽  
Zhijian Liao ◽  
...  
Keyword(s):  
Plant Growth ◽  
Environmental Science ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Light Emitting ◽  
Broad Application ◽  
Led Light ◽  
Broadband Emission ◽  
Application Prospects

The near-infrared (NIR) phosphor-converted light emitting diode (pc-LED) light sources have broad application prospects in environmental science, biomedical and plant growth fields. However, NIR phosphor still suffers from narrowband emission...

Electrically driven single microribbon based near-infrared exciton-polariton light-emitting diode

CrystEngComm ◽  
2021 ◽  
Author(s):  
Mingming Jiang ◽  
Fupeng Zhang ◽  
Kai Tang ◽  
Peng Wan ◽  
Caixia Kan
Keyword(s):  
High Performance ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Coherent Light ◽  
Light Emitting ◽  
Exciton Polaritons ◽  
Laser Devices

Achieving electrically-driven exciton-polaritons has drawn substantial attention toward developing ultralow-threshold coherent light sources, containing polariton laser devices and high-performance light-emitting diodes (LEDs). In this work, we demonstrate an electrically driven...

Light-emitting diodes as light sources for spectroscopy: Sensitivity to temperature

2017 ◽  
Vol 25 (6) ◽  
pp. 416-422 ◽  
Author(s):  
Clinton J Hayes ◽  
Kerry B Walsh ◽  
Colin V Greensill
Keyword(s):  
Ambient Temperature ◽  
Near Infrared ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Effect Of Temperature ◽  
Light Sources ◽  
Spectral Variation ◽  
Light Emitting ◽  
Full Intensity

Understanding of light-emitting diode lamp behaviour is essential to support the use of these devices as illumination sources in near infrared spectroscopy. Spectral variation in light-emitting diode peak output (680, 700, 720, 735, 760, 780, 850, 880 and 940 nm) was assessed over time from power up and with variation in environmental temperature. Initial light-emitting diode power up to full intensity occurred within a measurement cycle (12 ms), then intensity decreased exponentially over approximately 6 min, a result ascribed to an increase in junction temperature as current is passed through the light-emitting diode. Some light-emitting diodes displayed start-up output characteristics on their first use, indicating the need for a short light-emitting diode ‘burn in’ period, which was less than 24 h in all cases. Increasing the ambient temperature produced a logarithmic decrease in overall intensity of the light-emitting diodes and a linear shift to longer wavelength of the peak emission. This behaviour is consistent with the observed decrease in the IAD Index (absorbance difference between 670 nm and 720 nm, A670–A720) with increased ambient temperature, as measured by an instrument utilising light-emitting diode illumination (DA Meter). Instruments using light-emitting diodes should be designed to avoid or accommodate the effect of temperature. If accommodating temperature, as light-emitting diode manufacturer specifications are broad, characterisation is recommended.

scholarly journals Effect of 660 nm Light-Emitting Diode on the Wound Healing in Fibroblast-Like Cell Lines

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Myung-Sun Kim ◽  
Yong-Ick Cho ◽  
Min-Suk Kook ◽  
Sang-Chul Jung ◽  
Young-Hyun Hwang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Wound Healing ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Biological Effects ◽  
Soft Tissue Injuries ◽  
Light Emitting ◽  
Led Light ◽  
Red Led ◽  
And Migration

Light in the red to near-infrared (NIR) range (630–1000 nm), which is generated using low energy laser or light-emitting diode (LED) arrays, was reported to have a range of beneficial biological effects in many injury models. NIR via a LED is a well-accepted therapeutic tool for the treatment of infected, ischemic, and hypoxic wounds as well as other soft tissue injuries in humans and animals. This study examined the effects of exposure to 660 nm red LED light at intensities of 2.5, 5.5, and 8.5 mW/cm2for 5, 10, and 20 min on wound healing and proliferation in fibroblast-like cells, such as L929 mouse fibroblasts and human gingival fibroblasts (HGF-1). A photo illumination-cell culture system was designed to evaluate the cell proliferation and wound healing of fibroblast-like cells exposed to 600 nm LED light. The cell proliferation was evaluated by MTT assay, and a scratched wound assay was performed to assess the rate of migrating cells and the healing effect. Exposure to the 660 nm red LED resulted in an increase in cell proliferation and migration compared to the control, indicating its potential use as a phototherapeutic agent.

scholarly journals A Practical Method to Design Reflector-Based Light-Emitting Diode Luminaire for General Lighting

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Jinren Yan
Keyword(s):  
Light Emitting Diode ◽  
Spherical Surface ◽  
Target Surface ◽  
Practical Method ◽  
Optical Simulation ◽  
Light Sources ◽  
Aspheric Surface ◽  
Light Emitting ◽  
Led Light ◽  
Spherical Reflector

A reflector-based light-emitting diode (LED) luminaire structure that can achieve a large cut-off angle for general lighting is presented in this work. The proposed lighting unit mainly consists of a spherical reflector and a primary packaging lens that contains an aspheric surface and a spherical surface. The light rays emitted from the LED light source are well controlled by the spherical reflector and the aspheric surface of the lens for the purpose of obtaining a uniform illumination on the target surface. Both the ideal Lambertian LED and non-Lambertian LED light sources were employed to validate the proposed structure and the performance of the designed lighting units was analyzed by optical simulation. The results show that the light utilization efficiencies and the estimated uniformities are 92.96% and 91.11% for ideal Lambertian LED-based lighting unit and 93.31% and 91.64% for non-Lambertian LED-based lighting unit, respectively. Further analysis shows that the tolerances of horizontal, vertical, and rotational deviation of the both lighting units were about 2.0 mm, 1.0 mm, and 1.0°, respectively.

Responses of Favorita Potato Plantlets Cultured in Vitro under Fluorescent and Light-Emitting Diode (LED) Light Sources

2019 ◽  
Vol 96 (4) ◽  
pp. 396-402 ◽  
Author(s):  
Lili Jiang ◽  
Ziquan Wang ◽  
Guanghui Jin ◽  
Dianqiu Lu ◽  
Xuezhan Li
Keyword(s):  
Light Emitting Diode ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Potato Plantlets

Radiometric and Spectrophotometric Analysis of Third Generation Light-Emitting Diode (LED) Light-Curing Units

2007 ◽  
Vol 8 (2) ◽  
pp. 43-51 ◽  
Author(s):  
Barry M. Owens ◽  
Kelbin H. Rodriguez
Keyword(s):  
Spectral Distribution ◽  
Light Emitting Diode ◽  
Spectrophotometric Analysis ◽  
Battery Life ◽  
Light Sources ◽  
Third Generation ◽  
Light Emitting ◽  
Led Light ◽  
Restorative Materials ◽  
Light Curing

Abstract Aims Light-emitting diode (LED) polymerization of dental restorative materials has become increasingly popular. However, individual light-curing unit (LCU) functions (intensity and/or wavelength emission) may not conform to manufacturer specifications due to quality control issues. The purpose of this study was to evaluate the quality of irradiance, in terms of power density (intensity) and spectral distribution (peak wavelength), emitted from LED and quartz-tungsten halogen (QTH) LCUs in vitro. The battery expenditure of these LED units was also tested. Methods and Materials The intensity and spectral distribution from four third generation LED (Smartlite PS, Coltolux LED, radii Plus, Diopower) and one QTH (Schein Visible Cure) light sources were measured using six different dental curing light meters (Coltolux, Cure Right, Demetron 100, Demetron LED., Hilux, and Light Meter-200) and a visible-ultraviolet light spectrophotometer (Hitachi Elmer-Perkins). The battery life was also plotted for each light source following a 1500 second duration period. The data obtained from radiometric and spectrophotometric analysis was compared to manufacturer specifications. Results Radiometric evaluation revealed LED light units tested did not satisfy manufacturer claims for minimum intensities. Spectral emissions from the LED light sources did meet manufacturer requirements. No clinically appreciable battery drain was evidenced from testing all re-chargeable LED units. Conclusion Despite limitations LED technology appears to be an effective alternative for curing of lightactivated esthetic restorative materials. Additional advantages associated with LED curing lights include ergonomic handling capabilities, negative heat generation, and minimal maintenance concerns. Citation Owens BM, Rodriguez KH. Radiometric and Spectrophotometric Analysis of Third Generation Light- Emitting Diode (LED) Light-Curing Units. J Contemp Dent Pract 2007 February;(8)2:043-051.

PHOTOTHERAPY FOR MILD TO MODERATE ACNE VULGARIS WITH PORTABLE BLUE AND RED LED

2011 ◽  
Vol 04 (01) ◽  
pp. 45-52 ◽  
Author(s):  
GUANGDA LIU ◽  
CHANGE PAN ◽  
KAI LI ◽  
YUAN TAN ◽  
XUNBIN WEI
Keyword(s):  
Side Effects ◽  
Light Emitting Diode ◽  
Acne Vulgaris ◽  
Red Light ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Led Phototherapy ◽  
Red Led ◽  
Complete Treatment

In this paper, we studied portable blue and red light-emitting-diode (LED) light sources in phototherapy for mild to moderate acne vulgaris to evaluate the efficacy and tolerance of patients. Patients, randomly divided into blue and red groups, received either blue or red LED phototherapy twice a week for four weeks. After complete treatment, the number of lesions reduced by 71.4% in the blue group, in contrast to 19.5% in the red group. No obvious side effects were observed during and one month after the treatment, except for some mild dryness mentioned by several patients.

scholarly journals The Contribution of Different Spectral Sections to Increase Fresh Weight of Boston Lettuce

HortScience ◽  
2015 ◽  
Vol 50 (7) ◽  
pp. 1006-1010 ◽  
Author(s):  
Shih-Wei Kong ◽  
Hsin-Ying Chung ◽  
Ming-Yi Chang ◽  
Wei Fang
Keyword(s):  
Plant Growth ◽  
White Light ◽  
Light Emitting Diode ◽  
Green Light ◽  
Light Sources ◽  
Fluorescent Lamp ◽  
Fresh Weight ◽  
Yellow Light ◽  
Light Emitting ◽  
Active Radiation

Six types of light sources [0G, 20G, 40G, cool-white light-emitting diode (LED CW), cool-white fluorescent lamp (FLCW), and plant light fluorescent lamp (TLRA)] were used as the sole light sources to cultivate boston lettuce (Lactuca sativa L. cv. Ostinata). The photosynthetically active radiation (PAR) range was separated into five sections and the contributions of each spectral section on fresh weight (FW) were quantified. The results indicate that the conventional method of separating PAR into red, green, and blue at 100 nm apart was not accurate enough to clarify the contribution of different spectral sections to FW of boston lettuce. Green light (525–575 nm) at less than 30% of PAR is even more important than red (625–700 nm) and blue (400–475 nm) to plant growth. Yellow light (575–625 nm) has very little effect on plant growth.

P-Wave Visible–Shortwave–Near-Infrared (Vis-SW-NIR) Detection System for the Prediction of Soluble Solids Content and Firmness on Wax Apples

2019 ◽  
Vol 73 (10) ◽  
pp. 1135-1145
Author(s):  
Shih-Hao Hua ◽  
Hsun-Ching Hsu ◽  
Pin Han
Keyword(s):  
Near Infrared ◽  
Detection System ◽  
Light Emitting Diode ◽  
P Wave ◽  
Soluble Solids ◽  
Light Sources ◽  
Soluble Solids Content ◽  
Led Light ◽  
Highly Correlated ◽  
Solids Content

A nondestructive system for measuring the soluble solids content (SSC) and firmness of wax apples was developed using 670, 850, 880, 940, and 980 nm visible–shortwave–near-infrared (Vis-SW-NIR) light-emitting diode (LED) light sources and a silicon (Si) photodetector. These specified wavelengths are highly correlated with the SSC and the firmness of fruit. An LED light source was incident onto the fruit as parallel-polarized waves (P-wave) at the Brewster angle (θB) to minimize the interfacial reflection and maximize the C–H and O–H bonds absorption signals from the fruit. Partial least squares (PLS) regression is used to build calibration modes and analyze the prediction of the correlation ([Formula: see text]) and the root mean square error for prediction (RMSEP) of the reflected optical signals with SSC and firmness. This resulted in [Formula: see text] and RMSEP values of 0.87 and 0.66 °Bx, respectively, in SSC measurements and 0.80 and 1.16 N/cm2, respectively, in firmness measurements. Therefore, the result shows [Formula: see text] of SSC and firmness are 6.4% and 9% higher and the RMSEP are 14% and 20% lower, respectively, than those obtained using non-polarized LED light sources.

Evaluation of Color Rendering Index for LED and Fluorescent Light Sources

2015 ◽  
Vol 731 ◽  
pp. 22-26
Author(s):  
Huan Jiang ◽  
Min Huang ◽  
Fu Song Yang ◽  
Yu Liu
Keyword(s):  
Light Emitting Diode ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Color Science ◽  
Color Rendering Index ◽  
Different Color ◽  
Color Rendering

In order to assess the performances of different color rendering index (Ra, CRI, CQS, nCRI, R96a). The LED (light-emitting diode), fluorescent light sources and 30 printed color samples were used in our experiment. 20 observers were organized to carry out the color preference experiment, the visual data were accumulated to test the performances of the light sources and the results indicated that existing color rendering index have some deficiencies to assess the quality of the light source, which were needed to be modified for the theory of color science and industry application. The new CQS additional scales were calculated and the improvements were still insufficient for the LED light sources.

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