Extrahigh color rendering white light-emitting diode lamps using oxynitride and nitride phosphors excited by blue light-emitting diode

2007 ◽  
Vol 90 (5) ◽  
pp. 051109 ◽  
Author(s):  
Naoki Kimura ◽  
Ken Sakuma ◽  
Syunichiro Hirafune ◽  
Kenichiro Asano ◽  
Naoto Hirosaki ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Color Rendering

scholarly journals Chromaticity Study of Curcumin Dye Extracted from Curcuma longa L. Using for UV Light down Conversion for White Light Emitting Diode

2019 ◽  
Vol 290 ◽  
pp. 183-189
Author(s):  
Mahmood Al Shafouri ◽  
Naser Mahmoud Ahmed ◽  
Zainuriah Hassan ◽  
Munirah Abdullah Almessiere
Keyword(s):  
White Light ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Curcuma Longa ◽  
Color Temperature ◽  
Light Emitting ◽  
Chromaticity Coordinates ◽  
Major Factors ◽  
Color Rendering ◽  
Down Conversion

In thus study, Turmeric phosphor dye was extracted from Curcuma Longa L. via a simple technique using silica gel. The phosphor was used for light down-conversion of UV light for the manufacture white light emitting diode (WLED). The UV-LED was analyzed over 395nm wavelengths. The characteristics of the white light chromaticity were controlled by tuning the current and phosphor concentration. An optimum color rendering index (CRI) value of 63.4 was obtained. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for various currents and phosphor concentrations. The white phosphor exhibited CIE value of 0.355,0.338 and CCT of 4567 K. The concentration of phosphor and amount of applied current were confirmed to be major factors that control the intensity of white light emitted from the sample, where CIE and CRI of the emitted light steadily increased with the concentration of phosphor and current. Thus, phosphor concentration has a critical effect on conversion efficiency. Key words: Turmeric, phosphor, WLED, curcumin

Changes in light spectra modify secondary compound concentrations and BVOC emissions of Norway spruce seedlings

2020 ◽  
Author(s):  
Minna Kivimäenpää ◽  
Virpi Virjamo ◽  
Rajendra Prasad Ghimire ◽  
Jarmo Holopainen ◽  
Riitta Julkunen-Tiitto ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Blue Light ◽  
White Light ◽  
Carbon Allocation ◽  
Light Emitting Diode ◽  
Abiotic Stress Tolerance ◽  
Photon Flux ◽  
Emission Rates ◽  
Light Emitting ◽  
Light Spectra

Our objective was to study how changes in the light spectra affects growth, carbohydrate, chlorophyll, carotenoid, terpene, alkaloid and phenolic concentrations, and BVOC (biogenic volatile organic compound) emissions of Norway spruce (Picea abies) seedlings. This study was conducted during the growth of the third needle generation in plant growth chambers. Two light spectra with the main difference in proportion of blue light (400-500 nm) and equal photon flux densities were provided by LED (light-emitting diode) lamps: 1) control (white light + 12 % blue light) and 2) increased blue light (+B) (white light + 45% blue light). The +B treatment increased needle concentrations of total flavonoids and acetophenones. The major changes in the phenolic profile were an accumulation of astragalin derivatives and the aglycone of picein. +B decreased concentrations of the main alkaloid compound, epidihydropinidine, and it’s precursor, 2-methyl-6-propyl-1,6-piperideine, emission rates of limonene, myrcene and total monoterpenes, and concentrations of a few terpenoid compounds, mainly in stems. Growth, needle carbohydrates and pigments were not affected. The results suggest that supplemental blue light shifts carbon allocation between secondary metabolism routes, from alkaloid and terpenoid synthesis to flavonoid and acetophenone synthesis. The changes may affect herbivory and abiotic stress tolerance of Norway spruce.

Utilization of LiSrPO4:Eu phosphor and CuInS quantum dot for fabrication of high color rendering white light-emitting diode

2013 ◽  
Vol 92 ◽  
pp. 325-329 ◽  
Author(s):  
Woo-Seuk Song ◽  
Jong-Hoon Kim ◽  
Jeong-Hoon Lee ◽  
Hye-Seung Lee ◽  
Ho Seong Jang ◽  
...  
Keyword(s):  
Quantum Dot ◽  
White Light ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Color Rendering

scholarly journals High Efficiency and Color Rendering Quantum Dots White Light Emitting Diodes Optimized by Luminescent Microspheres Incorporating

Nanophotonics ◽  
2016 ◽  
Vol 5 (4) ◽  
pp. 565-572 ◽  
Author(s):  
Wei Chen ◽  
Kai Wang ◽  
Junjie Hao ◽  
Dan Wu ◽  
Jing Qin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
High Efficiency ◽  
Lattice Structure ◽  
Light Emitting Diode ◽  
Luminescent Properties ◽  
Color Temperature ◽  
High Quantum Efficiency ◽  
Light Emitting ◽  
Color Rendering

AbstractIn this research, we have developed an approach by incorporating quantum dots (QDs) with red emission into mesoporous silica microspheres through a non-chemical process and obtained luminescent microspheres (LMS). Owing to the lattice structure of LMS, QDs were effectively protected from intrinsic aggregation in matrix and surface deterioration by encapsulant, oxygen and moisture. The LMS composite has therefore maintained large extent luminescent properties of QDs, espe-cially for the high quantum efficiency. Moreover, the fabricated white light emitting diode (WLED) utilizing LMS and YAG:Ce yellow phosphor has demonstrated excellent light performance with color coordinates around (x = 0.33, y = 0.33), correlated color temperature between 5100 and 5500 K and color rendering index of Ra = 90, R9 = 95. The luminous efficiency of the WLED has reached up to a new record of 142.5 lm/W at 20 mA. LMS provide a promising way to practically apply QDs in lightings and displays with high efficiency as well as high stability.

The Color Mixing White-Light LEDs

2013 ◽  
Vol 378 ◽  
pp. 440-443
Author(s):  
Chiu Jung Yang ◽  
Chien Sheng Huang ◽  
Chih Wei Chen ◽  
Po Wen Chen
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Integrating Sphere ◽  
Light Spectrum ◽  
Light Emitting ◽  
Driver Circuit ◽  
Color Mixing ◽  
Color Rendering

Thepaperis discussedin coloruniformity study.The experiment divided into two steps in this study,first is modules design and simulation. Second is fabrication and measurement.After measure the LEDs property, calculating the ratio of each colored LEDs by using Grassmanns Law,modeling by Solidworks, and simulating the front study by optical software TracePro.Using four-color mixing with self-developed formula to avoid the present white light emitting diode patent, and the four-color grains are Red, Green, Blue and adding Y to modify the overall quality of the mixed light.The phosphorproduceSteabler-Wronsk hardly in the high temperatureas compared tofour-color mixing.Using four-color mixing to producehigher color rendering index than yellow phosphor.Series-parallel array of grain arrangement adopted to achieve the high demand for uniformity, while simplifying the design conditions by a certain current instead of the general mixed light-driven complex driver circuit,the completion of the mixing module using integrating sphere, light spectrum on the spectrophotometer, optical power, color coordinates values, such as mixing uniformity measurements.The chromaticity coordinates errors after complete results of the mixing module measurement and simulation can be controlled under (0.01x, 0.01y).

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