Electrical and Thermal Effects of Tunable LED Systems on Lighting and Non-Visual Biological Characteristics

Shen, Xuehua; Chen, Hong; Shi, Wei; Xiong, Qianjin

doi:10.1109/jphot.2020.2984667

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…The relationship between them is determined solely by the constant coefficient K m . As P(λ) of PC-WLEDs has been confirmed to vary with operating temperature and current [25], it is reasonable to assume that specific connections exist between luminous flux Φ v and temperature, as well as between luminous flux Φ v and current. If this assumption is valid, the expression ´780nm 380nm P(λ)V(λ)dλ might also relate to temperature and current by similar connections.…”

Section: Modeling With Electro-thermal Propertiesmentioning

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: Modeling With Electro-thermal Propertiesmentioning

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

Self Cite

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“…Since the tristimulus value Y represents luminance and generally is proportional to the luminous flux φ v , while chromaticity coordinate y can be approximated as in proportion to CCT [24], (6) therefore will be transformed into…”

Section: A Nonlinear Cct Linking Chromaticity Coordinates and Luminou...mentioning

confidence: 99%

Analysis and Tunable Models for Phosphor-Converted White Light-Emitting Diode Based on Spectral Compensation

et al. 2023

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The correlated color temperature (CCT) and color rendering index (CRI) are two significant indicators related to the color appearance and visual effects of illumination. This paper concentrates on dynamic dimming for phosphor-converted (PC) white LEDs to achieve tunable CCT and adequate CRI, via compensation of red/green spectra. The LED systems described have a simple configuration consisting of a PC white LED, a monochrome green LED and a monochrome red LED, which can be individually driven. Compared to individual PC white LEDs, both the spectral continuity and uniformity of the mixed white light are enhanced. The tunable dimming models are proposed by combination of spectral colorimetry and photo-electro-thermal (PET) theory, thus multi-physics effects are involved. From the modeling process and results, the nonlinear characteristics are observed. Experimental verifications present good agreement existing between calculations and measurements, both in terms of values and variation trends. These proposed models could be effective tools to figure out photometric characteristics and visual perception of illumination. On the other hand, they could provide schemes of reference to improve the illumination environment adapting to various special occasions and personal preferences.

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A circadian lighting method for low blue light hazard, high color rendering index, and tunable circadian stimulus

Liu

Jiang

et al. 2024

Optics & Laser Technology

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Electrical and Thermal Effects of Tunable LED Systems on Lighting and Non-Visual Biological Characteristics

Cited by 3 publications

References 19 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 Tunable Models for Phosphor-Converted White Light-Emitting Diode Based on Spectral Compensation

A circadian lighting method for low blue light hazard, high color rendering index, and tunable circadian stimulus

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