Defining phosphor luminescence property requirements for white AC LED flicker reduction

Tan, Jianchuan; Narendran, Nadarajah

doi:10.1016/j.jlumin.2015.05.064

Cited by 17 publications

(17 citation statements)

References 25 publications

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“…Sin embargo, puede causar problemas cuando la luz de este circuito se utilice en fotografía o filmación digital. Una solución consiste en colocar difusores de material fosforescente en la luminaria, de manera de filtrar las variaciones de intensidad lumínica [18]. Otra solución consiste en conectar tres circuitos iguales con alimentación trifásica; con ello, se produciría un efecto de "rectificación lumínica" de 6 ondas, que prácticamente anulan el efecto de parpadeo.…”

Section: (20)unclassified

Analysis of Multistage Pulsed Current Drivers for Solid State Lighting Devices

Álvarez

2019

Rev. Téc. Ing. Univ. Zulia.

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Section: (20)unclassified

Analysis of Multistage Pulsed Current Drivers for Solid State Lighting Devices

Álvarez

2019

Rev. Téc. Ing. Univ. Zulia.

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“…The massive heat generated during the conversion process also causes degradation of the embedded phosphor, which severely shortens the service lifetime of WLEDs 7 , 8 . Thus, in view of these shortcomings of DC-LEDs, AC-LEDs have received widespread attention in both academic research and industrial applications owing to their remarkable benefits of more compact volume, cheaper manufacturing cost, greater energy usage efficiency, and longer service life 9 , 10 . Despite so many potential advantages, a pressing issue limiting the commercial application of AC-LEDs is the flicker effect, which is mainly caused by the unavoidable 5–20 ms dimming time in each AC cycle.…”

Section: Introductionmentioning

confidence: 99%

Enhanced blue-light excited cyan-emitting persistent luminescence of BaLu2Al2Ga2SiO12:Ce3+, Bi3+ phosphors for AC-LEDs via defect modulation

et al. 2022

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Alternating current light-emitting diodes (AC-LEDs) have received significant attention from both academia and industry due to their remarkable benefits of more compact volume, cheaper manufacturing cost, greater energy usage efficiency, and longer service life. One of the most significant challenges for AC-LEDs is the flicker effect, which is mainly caused by the unavoidable 5–20 ms dimming time. Aiming to reduce the flicker effect, we designed a series of excellent blue-light excited cyan-emitting persistent luminescence (PersL) phosphors BaLu2Al2Ga2SiO12:Ce3+, Bi3+ via defect engineering of co-doping Bi3+. Interestingly, we found that co-doping Bi3+ not only effectively enhanced the PersL intensity, but also regulated the PersL lifetime of this phosphors. As the Bi3+ co-doping concentration increases to 0.01, the τ80 value (the time when the PersL intensity decreases to 80% of the initial intensity) increases from 0.24 to 19.61 ms, which proves to be effective in compensating the flicker effect of AC-LEDs. A new method of generating white light emission during the dimming time through adding the blue-light excited cyan PersL phosphor to the original orange-red PersL phosphor was proposed and an AC-LED lamp with a decreased percent flicker of 48.15% was fabricated, which is significantly better than the other currently reported AC-LED devices based on PersL phosphors. These results demonstrate that BaLu2Al2Ga2SiO12:Ce3+, Bi3+ might be an attractive material for low-flicker AC-LEDs.

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“…17 An AC-LED generates flicker at frequencies of 120 Hz (8.3 ms) in North America and 100 Hz (10 ms) in Europe and in China. 20 Therefore, the AC-LED device for illumination must be driven by a frequency higher than 120 Hz. However, it is expensive and complicated to increase the frequency of LEDs or optimize the design of the circuit.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the LED flicker frequencies should be above this range . An AC‐LED generates flicker at frequencies of 120 Hz (8.3 ms) in North America and 100 Hz (10 ms) in Europe and in China . Therefore, the AC‐LED device for illumination must be driven by a frequency higher than 120 Hz.…”

Section: Introductionmentioning

confidence: 99%

Warm white light emitting from single composition SrGa₁₂O₁₉:Dy³⁺ phosphors for AC‐LED

et al. 2019

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Making illumination light sources become comfortable to the human eye is a long‐term effort, which justifies the current research on warm white‐light‐emitting diodes (w‐LEDs). In this work, a novel phosphor for w‐LEDs, namely SrGa12O19: Dy3+(SGO: Dy3+), with a low‐color temperature (CT) was designed and synthesized. The crystal structure, the luminescence properties, the thermoluminescence properties and the stability of SGO: Dy3+ were investigated. We demonstrate outstanding luminescent characteristics and excellent stabilities. The intensity of emission light keep remained when excited by a flickering light source with a chopping speed or off‐time of a few seconds, which indicates that the SGO: Dy3+ phosphor has anti‐flicker properties that will be useful for potential applications, as LEDs driven by alternating current (AC‐LED). The chromaticity coordinates and the correlated color temperature (CCT) of SGO: Dy3+ phosphors with different Dy3+ concentrations are close with an optimal doping at 4.00 mol% Dy3+ for chromaticity coordinate (0.4269, 0.4348) and a lowest CCT of 3361 K. The perfect weatherability of this phosphor was also confirmed since the phosphorescence intensity and the color were stable at high temperature and in a high humidity environment. The performance obtained shows that SGO: Dy3+ is a suitable candidate for illumination sources that are beneficial to human health.

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Defining phosphor luminescence property requirements for white AC LED flicker reduction

Cited by 17 publications

References 25 publications

Analysis of Multistage Pulsed Current Drivers for Solid State Lighting Devices

Analysis of Multistage Pulsed Current Drivers for Solid State Lighting Devices

Enhanced blue-light excited cyan-emitting persistent luminescence of BaLu2Al2Ga2SiO12:Ce3+, Bi3+ phosphors for AC-LEDs via defect modulation

Warm white light emitting from single composition SrGa₁₂O₁₉:Dy³⁺ phosphors for AC‐LED

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Defining phosphor luminescence property requirements for white AC LED flicker reduction

Cited by 17 publications

References 25 publications

Analysis of Multistage Pulsed Current Drivers for Solid State Lighting Devices

Analysis of Multistage Pulsed Current Drivers for Solid State Lighting Devices

Enhanced blue-light excited cyan-emitting persistent luminescence of BaLu2Al2Ga2SiO12:Ce3+, Bi3+ phosphors for AC-LEDs via defect modulation

Warm white light emitting from single composition SrGa12O19:Dy3+ phosphors for AC‐LED

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Warm white light emitting from single composition SrGa₁₂O₁₉:Dy³⁺ phosphors for AC‐LED