Impact of blue filtering on effective modulation bandwidth and wide-angle operation in white LED-based VLC systems

Anous, Noha; Ramadan, Tarek A.; Abdallah, Mohamed; Qaraqe, Khalid; Khalil, Diaa

doi:10.1364/osac.1.000910

Cited by 18 publications

(19 citation statements)

References 18 publications

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“…Therefore, combining these two solutions and using a LED package with two chips and two phosphors is the suggested idea to obtain all three requirements of high CRI, luminous efficacy and tunable color. Using Beer's law [19][20][21][22] and linear conversion in the lighting device simulation process, we introduce a color design model that can slightly adjust the chromatic indication. The simulated WLED model consists of the yellow-emitting YAG:Ce phosphor and high performance chromatic LED chips.…”

Section: Introductionmentioning

confidence: 99%

The impacts of red-emitting phosphor Mg8Ge2O11F2:Mn4+ on the color rendering index of convex-dual-layer remote phosphor WLEDs at 5600 K

2021

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The poor color rendering index (CRI) induced by mono chip and phosphor configuration in the conventional white-light light-emitting diode (LED) urges for developments in both packaging and material, thus, a modern lighting solution was introduced. The dual-layer phosphor package is an innovative configuration that can retain the lumen output of conventional white light emitting diode (WLED) while also enhancing color quality. The structure of dual-layer phosphor package that was proposed includes two chips and one phosphor. The priority in this research is to keep improving the lighting properties of WLED, therefore, further experiments with this dualchips and dual-phosphor package are conducted. The lighting properties of LED are measured multiple times with its nitride-based phosphor being altered in proportions and densities each occasion, the results are calculated with a color design model made specifically to monitor and adjust the color of white-light from LED to match desired outcome. The WLED at 5600 K correlated color temperature (CCT) is the sole research object of the experiments. The measured parameters from the 5600 K WLED and the color coordinates of CIE 1931 simulated from the color design model show that 0.0063 is the highest possible discrepancy at 5600 K (CCT). The information from this manuscript provide the manufacturers with the most efficient approach to create a white LED that has good color quality, high CRI and luminous flux.

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Section: Introductionmentioning

confidence: 99%

The impacts of red-emitting phosphor Mg8Ge2O11F2:Mn4+ on the color rendering index of convex-dual-layer remote phosphor WLEDs at 5600 K

2021

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“…Patterned structure of remote WLEDs with clear center within the border region and no phosphor-covered exterior can result in better thermal consistency and color quality output [18]. Furthermore, the sapphire substrate in different patterned remote phosphor structure are more proficient in terms of color temperature homogeneity compared to far-field pattern [19][20][21]. To improve the light output of LEDs, remote phosphor which has dual layer package is proposed.…”

Section: Introductionmentioning

confidence: 99%

The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote phosphor LED

2020

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Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce 3+ under green phosphor YPO4:Ce 3+ ,Tb 3+ or red phosphor LiLaO2:Eu 3+. After that, we search for suitable concentration of LiLaO2:Eu 3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu 3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu 3+ , the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce 3+ ,Tb 3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu 3+ and YPO4:Ce 3+ ,Tb 3+ over increase. Results are verified by Mie theory and Beer's Law and can be applied to practical manufacturing of high quality WLEDs.

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“…The mechanism of this method is to keep the advantages found in previous studies and discard the unwanted traits by evaluating the performance of WLED with the new phosphor package while adjusting the phosphor arrangement until reaching the highest values in quality indicators. We also based on Beer's law [17][18][19] to propose an innovative and exclusive shading configuration model that changes to response to the request for an unobtrusive color distinction of white-light LEDs. This new method demonstrates through experimental results and comparison between important optical properties the superior results that can be achieved by changing the phosphor package and phosphor concentration, which is an approach that has not been applied before.…”

Section: Introductionmentioning

confidence: 99%

Y2O3:Ho3+ and ZnO:Bi3+: a selection for enhancing color quality and luminous flux of WLEDs

Loan

Anh

2020

IJECE

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As the luminescence industry develops, the white light light-emitting diode (LED) package with a single chip and a single phosphor although produces good luminous flux but has a poor color rendering index (CRI) can no longer fulfill the requirements of modern lighting applications. Therefore, this research is conducted to response to the urgent demands of improving other lighting qualities of WLED while maintaining high luminous efficiency. To achieve this target, we applied the new WLED package, which contains multi-chips and multi-phosphor layers, and have obtained outstanding results in both CRI and luminous efficacy. Two types of phosphor used in the WLED package are Y2O3:Ho3+ and ZnO:Bi3+. A color configuration model is also developed to adjust the shading of the white-light LED module. The results of this research show that the triple-layer phosphorhas the best performance when applied in a white-light LED package, which is demonstrated through better color quality, CRI and luminous efficacy, The manufacturers can rely on this research to produce the optimal-quality WLED, or WLED that is appropriate to their quality demands.

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Impact of blue filtering on effective modulation bandwidth and wide-angle operation in white LED-based VLC systems

Cited by 18 publications

References 18 publications

The impacts of red-emitting phosphor Mg8Ge2O11F2:Mn4+ on the color rendering index of convex-dual-layer remote phosphor WLEDs at 5600 K

The impacts of red-emitting phosphor Mg8Ge2O11F2:Mn4+ on the color rendering index of convex-dual-layer remote phosphor WLEDs at 5600 K

The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote phosphor LED

Y2O3:Ho3+ and ZnO:Bi3+: a selection for enhancing color quality and luminous flux of WLEDs

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