Design of binder-free phosphor paste for warm white LEDs

Kwon, Seok Bin; Jeong, Seong Guk; Choi, Seung Hee; Yoo, Jung Hyeon; Yang, Woo Seok; Yoo, Jinsu; Song, Young Hoon; Yoon, Dae Ho

doi:10.1016/j.optmat.2018.06.042

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…For the GaN chip, rising temperature can cause not only a decrease in optical power of the initial blue spectrum, but also a red shift of the peak wavelength that finally leads to a lower match with the excitation spectrum of YAG:Ce 3+ phosphors [32]. For YAG:Ce 3+ phosphors in the coating layer, the energy difference between the ground state 4 f and excited state 5d generally reduces with rising temperature, which will contribute to degradation in conversion efficiency [33]. In short, when the PC-WLED driven by a higher current, the thermal effects of the GaN chip and phosphors will have impacts on the components and structures of the mixed white light, and thus errors caused by idealization in the measurement model of CAF will also slightly increase.…”

Section: Photo-electro-thermal Properties Of Cafmentioning

confidence: 99%

Measurement model of circadian action factor of phosphor-converted white LEDs based on photometric, electrical, and thermal properties

Shen,

Chen,

et al. 2024

Metrologia

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Light stimulus is confirmed to have critical non-visual biological effects on human beings, and thus evaluation of lighting quality should not be limited to traditional visual performance. The circadian action factor (CAF) has been put forward to quantify such non-visual effects of light sources. This paper focuses on studying the photometric, electrical, and thermal properties of widely used phosphor-converted white LEDs (PC-WLEDs), and establishes an indirect measurement model of CAF regarding temperature, current and excitation wavelength. During modeling, the spectral power distribution (SPD) of PC-WLEDs is described as an extended Gaussian function of the double-color (blue-yellow) spectrum. In verifications, the remarkable consistency is obtained between indirect measurements and direct calculations, while the maximum relative errors do not exceed 2.6% and the mean relative errors do not exceed 0.9%. The proposed measurement model involves a series of optical tests and calibrations, which are simple for LED system designers to comply with. It offers an effective tool to quantify the PC-WLEDs’ non-visual biological effects on human beings, avoiding costly optical instruments and laborious calculations. Furthermore, it provides a potential theoretical foundation for realizing human-centric assessment, regulation and control of artificial lighting.

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Section: Photo-electro-thermal Properties Of Cafmentioning

confidence: 99%

Measurement model of circadian action factor of phosphor-converted white LEDs based on photometric, electrical, and thermal properties

Shen,

Chen,

et al. 2024

Metrologia

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“…In white LEDs, the blue LED chip turns the injected electrical power into the blue light accompanied with a fraction of heat dissipation. YAG:Ce phosphors then partially absorb the emitted blue light through the allowed 4f 1 -5d 1 transition and emit yellow light via the reverse 5d 1 -4f 1 transition [4]. The desired white light is consequently generated by mixture of the transmitted blue light and converted yellow light.…”

Section: Introductionmentioning

confidence: 99%

“…This is the so-called thermal quenching effect. Especially for high-power white LEDs, the thermal quenching effect becomes more serious, as heat generated in packages will increase with increasing power consumption [4], [17]. Therefore, it is no accident that good thermal management for the high-power phosphor-converted LED has always been a key design parameter for both packaging and system application.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Modeling of Optical and Thermal Properties of Phosphor Converted White Light Emitting Diode

et al. 2019

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Based on the energy flow inside phosphor materials, a prediction model and its modeling method for the thermal effect and optical properties of phosphor converted white light emitting diode (LED) are proposed in this paper. With the phosphor characteristics (excitation wavelength, phosphor temperature, thickness, light absorption and conversion coefficients), it is possible to accurately quantify the heat dissipation coefficient and optical power of the white LED device, and then to estimate the emission power and luminous flux. The modeling consists of a series of optical and thermal evaluation, which are simple for LED designers to comply. Using samples of LED sources and phosphor material, the proposed prediction model has been validated in experiments, where good agreements between calculations and practical measurements have been achieved.

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Thermally stable double perovskite Ca2YTaO6: Tb3+, Eu3+ phosphor for warm white LEDs

Lü,

Mai,

Fan

et al. 2024

J Mater Sci: Mater Electron

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Design of binder-free phosphor paste for warm white LEDs

Cited by 5 publications

References 21 publications

Measurement model of circadian action factor of phosphor-converted white LEDs based on photometric, electrical, and thermal properties

Measurement model of circadian action factor of phosphor-converted white LEDs based on photometric, electrical, and thermal properties

Analysis and Modeling of Optical and Thermal Properties of Phosphor Converted White Light Emitting Diode

Thermally stable double perovskite Ca2YTaO6: Tb3+, Eu3+ phosphor for warm white LEDs

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