Datasheet-based methodology for CCT and luminous flux estimation in mixed-LED lighting sources

2020 ◽  
Author(s):  
Thais E. Bolzan ◽  
Bruno F. Almeida ◽  
Mateus O. K. Pereira ◽  
Renan R. Duarte ◽  
Vitor C. Bender ◽  
...  
Keyword(s):  
Maximum Error ◽  
Luminous Flux ◽  
Measured Data ◽  
Operating Conditions ◽  
Color Temperature ◽  
Experimental Setup ◽  
Light Emitting ◽  
Led Lighting ◽  
Flux Estimation ◽  
White Light Emitting Diodes

This work proposes a datasheet-based methodology to estimate the correlated color temperature (CCT) and the luminous flux of one or a combination of multiple white Light-Emitting Diodes (LEDs). This methodology is based on the interaction between the different domains (colorimetrical, optical, thermal and electrical) that control the LED's behavior. An experimental setup with LEDs of 4000K and 6500K CCT was built and tested under multiple operating conditions, in order to verify the accuracy of the proposed method. Results presented good correlation between estimated and measured data, with a maximum error of 1.05% for CCT and 3.13% for luminous flux.

Optimization Spectrum of White Light Emitting Diodes Based on Correlated Color Temperature and Luminous Flux

2015 ◽  
Vol 44 (10) ◽  
pp. 1030001
Author(s):  
黄马连 HUANG Ma-lian ◽  
陈焕庭 CHEN Huan-ting ◽  
周小方 ZHOU Xiao-fang ◽  
蔡嘉毅 CAI Jia-yi ◽  
周锦荣 ZHOU Jin-rong ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Color Temperature ◽  
Light Emitting ◽  
White Light Emitting Diodes

scholarly journals Novel lighting properties of white LEDs with two-layered remote phosphor package using red-emitting α-SrO·3B2O3:Sm2+ phosphor

2017 ◽  
Vol 35 (3) ◽  
pp. 618-625
Author(s):  
Tran Hoang Quang Minh ◽  
Nguyen Huu Khanh Nhan ◽  
Nguyen Doan Quoc Anh ◽  
Hsiao-Yi Lee
Keyword(s):  
Lower Layer ◽  
Luminous Flux ◽  
Color Temperature ◽  
Phosphor Layer ◽  
Light Emitting ◽  
White Leds ◽  
Color Uniformity ◽  
Remote Phosphor ◽  
White Light Emitting Diodes ◽  
Color Rendering

AbstractThis paper investigates a method for improving the lighting performance of white light-emitting diodes (WLEDs), packaged using two separating remote phosphor layers, yellow-emitting YAG:Ce phosphor layer and red-emitting α-SrO·3B2O3:Sm2+ phosphor layer. The thicknesses of these two layers are 800 μm and 200 μm, respectively. Both of them have been examined at average correlated color temperatures (CCT) of 7700 K and 8500 K. For this two-layer model, the concentration of red phosphor has been varied from 2 % to 30 % in the upper layer, while in the lower layer the yellow phosphor concentration was kept at 15 %. It was found interesting that the lighting properties, such as color rendering index (CRI) and luminous flux, are enhanced significantly, while the color uniformity is maintained at a level relatively close to the level in one-layer configuration (measured at the same correlated color temperature). Besides, the transmitted and reflected light of each phosphor layer have been revised by combining Kubelka-Munk and Mie-Lorenz theories. Through the analysis, it is demonstrated that the packaging configuration of two-layered remote phosphor that contains red-emitting α-SrO·3B2O3:Sm2+ phosphor particles provides a practical solution to general WLEDs lighting.

scholarly journals Using CaCO3-doped package to improve correlated color temperature uniformity of white light-emitting diodes

2021 ◽  
Vol 11 (6) ◽  
pp. 4817
Author(s):  
My Hanh Nguyen Thi ◽  
Nguyen Thi Phuong Loan ◽  
Thuc Minh Bui ◽  
Hoang Van Ngoc
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Luminous Flux ◽  
Color Temperature ◽  
Resin Matrix ◽  
Light Emitting ◽  
Color Quality ◽  
Color Uniformity ◽  
Stability Enhancement ◽  
White Light Emitting Diodes

<span>The white light-emitting diode (WLED) has been the most advance lighting method currently, however, the fabrication process of this configuration still has drawbacks which negatively affect its color quality. This research was conducted to provide a method for WLED’s lighting output enhancement. Since CaCO<sub>3</sub> particles are excellent for thermal stability enhancement, especially when being combined with an adhesive substance, we decided to integrate CO<sub>3</sub> particles into resin matrix such as melamine formaldehyde (MF) and investigate their influences on the optical properties, including color uniformity and lumen output, of the WLED. The results showed that CaCO3 and MF resin are beneficial to the light scattering efficiency, which results in higher luminous flux and chromatic quality for WLED packages. In addition to that, the appropriate amounts of MF resin and CaCO<sub>3</sub> for reaching the best lumen efficiency and color quality are figured out at 1% and 10%, respectively. Moreover, another advantage of using MF resin and CaCO<sub>3</sub> for fabricating WLEDs is cost effectiveness. Hence, it has turned out that CaCO<sub>3</sub> and MF resins can be potential materials for next high-quality WLED generations.</span>

scholarly journals Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

2021 ◽  
Vol 10 (3) ◽  
pp. 1709-1717
Author(s):  
My Hanh Nguyen Thi ◽  
Phung Ton That
Keyword(s):  
Blue Light ◽  
White Light ◽  
Sio2 Nanoparticles ◽  
Luminous Flux ◽  
Nano Particles ◽  
Color Temperature ◽  
Refractive Indices ◽  
Light Emitting ◽  
White Leds ◽  
White Light Emitting Diodes

SiO2 nano-particles have been examined in a distant phosphor structure for the elevated luminous quality and better consistency of white light-emitting diodes with angular-dependent associated color temperature (CCT). The luminous scattering ability could be increased by applying SiO2 nano-particles contain silicone to the outside of the phosphorus coating. In specific, the strength of blue light at wide angles is increased and differences in CCT can be minimized. In addition, owing to the sufficient refractive indices of silicone-containing SiO2 nanoparticles between the air and phosphorus layers, the luminous flux was improved. This new configuration decreases angular-dependent CCT deviations in the range of -700 to 700 from 1000 to 420 K. In comparison, at a 120 mA driving current, the rise of lumen flux increased by 2.25% relative to an usual distant phosphor structure without SiO2 nano-particles. As a result, in a distant phosphor structure, the SiO2 nano-particles could not only enhance the uniformity of illumination but also enhance the output of light.

White light emitting diodes with enhanced CCT uniformity and luminous flux using ZrO2 nanoparticles

Nanoscale ◽  
2014 ◽  
Vol 6 (10) ◽  
pp. 5378-5383 ◽  
Author(s):  
Kuo-Ju Chen ◽  
Hau-Vei Han ◽  
Hsin-Chu Chen ◽  
Chien-Chung Lin ◽  
Shih-Hsuan Chien ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Color Temperature ◽  
Zro2 Nanoparticles ◽  
Light Emitting ◽  
White Light Emitting Diodes

To enhance the uniformity of correlated color temperature (CCT) and luminous flux, we integrated ZrO2 nanoparticles into white light-emitting diodes.

scholarly journals Light Output, Thermal Properties, and Reliability of Using Glass Phosphors in WLED Packages

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 239
Author(s):  
Chin-Chuan Huang ◽  
Tsung-Han Weng ◽  
Chun-Liang Lin ◽  
Yan-Kuin Su
Keyword(s):  
Thermal Properties ◽  
Yttrium Aluminum Garnet ◽  
Saturated Vapor ◽  
Light Output ◽  
Junction Temperature ◽  
Color Temperature ◽  
Light Emitting ◽  
Chromaticity Coordinate ◽  
White Light Emitting Diodes ◽  
Color Rendering

White-light-emitting diodes (WLED) based on yttrium aluminum garnet (YAG) phosphors sintered with glass (PiG) and with silicone (PiS) are compared in terms of their light properties, temperature properties and reliability.The complete YAG phosphor was doped with an encapsulant traditional WLED (PiS WLED), and the WLED was covered with PiG (PiG WLED). PiG was made by sintering glass powder and YAG phosphor at the ratio of 87:13 (%), and the correlated color temperature (CCT) was 5564 K. The CCT of the PiG WLED with the YAG doping concentration of 8.5 wt.% approximated 5649 K. The initial light output of the PiG WLED was 6.4% lower than that of the PiS WLED. Under 1008 h and 350 mA aging, PiG WLED and PiS WLED’ light output, CCT and color rendering index variation rates were all within 1%. In the saturated vapor-pressure test, no sample exhibited red ink infiltration, light nor peeling between the encapsulant and the lead-frame. Compared with that of the PiS WLED, the junction temperature of the PiG WLED reduced from 88.4 °C to 81.3 °C. Thermal resistance dropped from 37.4 °C/W to 35.6 °C/W. The PiG WLED presented a better CIE (Commission Internationale de l’Eclairage) 1931 chromaticity coordinate (x,y) concentration and thermal properties than the PiS WLED.

scholarly journals Preparation of Bismuth Oxide Photocatalyst and Its Application in White-light LEDs

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yen-Chang Chu ◽  
Gang-Juan Lee ◽  
Chin-Yi Chen ◽  
Shih-Hsin Ma ◽  
Jerry J. Wu ◽  
...  
Keyword(s):  
Bismuth Oxide ◽  
White Light ◽  
Front Surface ◽  
Color Temperature ◽  
Spray Pyrolysis Method ◽  
Light Emitting ◽  
White Leds ◽  
Air Purifier ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

Bismuth oxide photocatalysts were synthesized and coated on the front surface of phosphor-converted white light-emitting diodes to produce a safe and environmentally benign lighting source. Bismuth oxide photocatalyst powders were synthesized with a spray pyrolysis method at 500°C, 600°C, 700°C, and 800°C. Using the absorption spectrum in the blue and UV regions of the bismuth oxide photocatalysts, the blue light and UV leakage problems of phosphor-converted white LEDs can be significantly reduced. The experimental results showed that bismuth oxide photocatalyst synthesized at 700°C exhibited the most superior spectrum inhibiting ability. The suppressed ratio reached 52.33% in the blue and UV regions from 360 to 420 nm. Related colorimetric parameters and the photocatalyst decomposition ability of fabricated white-light LEDs were tested. The CIE chromaticity coordinates(x,y)were (0.349, 0.393), and the correlated color temperature was 4991 K. In addition, the coating layer of photocatalyst can act as an air purifier and diffuser to reduce glare. A value of66.2±0.60 ppmv of molecular formaldehyde gas can be decomposed in 120 mins.

scholarly journals Widely color-temperature low-luminosity-loss electrochromic-tuned white light-emitting diodes

Optik ◽  
2020 ◽  
Vol 203 ◽  
pp. 163994
Author(s):  
Yu-Yi Kuo ◽  
Chiu-Chang Huang ◽  
Wei-Ting Chen ◽  
Ting-Hsiang Chang ◽  
Hsin-Che Lu ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Color Temperature ◽  
Light Emitting ◽  
White Light Emitting Diodes
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