Spectral Optimization of White LED Based on Mesopic Luminance and Color Gamut Volume for Dim Lighting Conditions

Li, Hung-Chung; Sun, Pei‐Li; Huang, Yennun; Luo, Ming Ronnier

doi:10.3390/app10103579

Cited by 7 publications

(3 citation statements)

References 23 publications

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“…This was a claimed advantage during the transition process from high-pressure sodium to white light-emitting diode (LED) light sources a decade ago. Many works have been dedicated to optimizing high mesopic efficiency light sources [14][15][16]. Although mesopic vision applications in road lighting have been widely accepted, Gibbson et al's work showed that there are no significant differences in the detection distances for high and low correlated color temperature (CCT) sources when the speed is over 56 km/h [17].…”

Section: Introductionmentioning

confidence: 99%

The Circadian Effect Versus Mesopic Vision Effect in Road Lighting Applications

Ding

et al. 2020

Applied Sciences

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Several models on the circadian effect have been applied to indoor circadian lighting design, but applications in road lighting have not yet been clarified. Based on existing models and circadian research, we examined equivalent melanopic lux (EML), circadian light (CLA), and circadian stimulus (CS) representing the circadian effect and the S/P ratio representing the mesopic vision effect, among a dataset of light sources at photopic adaptation illuminance values of 1, 3, 10, 30, and 100 lx. The results show that the S/P ratio correlates with EML and CS (or CLA) much stronger than it correlates with color temperature. The EMLs of light sources are below 50 EML in mesopic vision, and the CSs of most light sources are below or around the threshold value of 0.05. We conclude that the circadian effect is not a significant issue in mesopic vision under most conditions and that optimization for mesopic efficiency is still a good strategy. There are quite a few light sources that may achieve both ideal mesopic efficiency and low CS. This work clarifies the circadian effect and mesopic vision effect performance of light sources in mesopic vision and will help guide choosing suitable light sources and optimization strategies for road lighting.

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Section: Introductionmentioning

confidence: 99%

The Circadian Effect Versus Mesopic Vision Effect in Road Lighting Applications

Ding

et al. 2020

Applied Sciences

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“…Compared to previous spectral optimisation studies [6,58,[60][61][62][63]100,101,[115][116][117][118], this work provides at the authors' best knowledge one of the most comprehensive multichannel LED datasets for metamer spectra. More advanced analyses between additional colour quality metrics are possible with the optimised spectra, which we did not fully exploit.…”

Section: Discussionmentioning

confidence: 99%

Melanopic Limits of Metamer Spectral Optimisation in Multi-Channel Smart Lighting Systems

et al. 2021

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Modern indoor lighting faces the challenge of finding an appropriate balance between energy consumption, legal requirements, visual performance, and the circadian effectiveness of a spectrum. Multi-channel LED luminaires have the option of keeping image-forming metrics steady while varying the melanopic radiance through metamer spectra for non-visual purposes. Here, we propose the theoretical concept of an automated smart lighting system that is designed to satisfy the user’s visual preference through neural networks while triggering the non-visual pathway via metamers. To quantify the melanopic limits of metamers at a steady chromaticity point, we have used 561 chromaticity coordinates along the Planckian locus (2700 K to 7443 K, ±Duv 0 to 0.048) as optimisation targets and generated the spectra by using a 6-channel, 8-channel, and 11-channel LED combination at three different luminance levels. We have found that in a best-case scenario, the melanopic radiance can be varied up to 65% while keeping the chromaticity coordinates constant (Δu′v′≤7.05×10−5) by using metamer spectra. The highest melanopic metamer contrast can be reached near the Planckian locus between 3292 and 4717 K within a Duv range of −0.009 to 0.006. Additionally, we publish over 1.2 million optimised spectra generated by multichannel LED luminaires as an open-source dataset along with this work.

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“…The illuminance value presented in the upperleft corner can be derived by calculating the area under the curve within the wavelength range of 390-830 nm. This range is also referred to as the CIE 2008 photopic luminous efficiency function (E(λ)), which represents the average spectral sensitivity of human vision to light [45]. Thus, effective conversion would enable the use of a spectrometer to evaluate photovoltaic performance under low-illuminance conditions.…”

Section: Experimental and Validation Proceduresmentioning

confidence: 99%

Indoor PV Modeling Based on the One-Diode Model

Teh,

Drieberg,

Hasan

et al. 2024

Applied Sciences

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The use of photovoltaic (PV) panels in interior spaces is expected to increase due to the proliferation of low-power sensor devices in the IoT domain. PV models are critical for estimating the I–V curves that define their performance at various light intensities. These models and the extraction of their parameters have been extensively studied under outdoor conditions, but their indoor illumination performance is less studied. With respect to the latter, several studies have used the parameter-scaling technique. However, the model’s accuracy degrades when the light level decreases. In this study, we propose a simple PV modeling technique that can be applied at various illuminance levels by only using characteristic points (short-circuit current, open-circuit voltage, and maximum-power voltage points) at a reference illumination level. The model uses the characteristic point translation technique to translate the reference characteristic points to other operating conditions. Then, parameter extraction technique is used to extract the model’s parameters. The proposed model’s accuracy is verified using two commercial PV panels and different indoor lighting technologies. The results indicate that the proposed model outperforms the other examined works in terms of accuracy, with an average improvement of 15.75%.

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Spectral Optimization of White LED Based on Mesopic Luminance and Color Gamut Volume for Dim Lighting Conditions

Cited by 7 publications

References 23 publications

The Circadian Effect Versus Mesopic Vision Effect in Road Lighting Applications

The Circadian Effect Versus Mesopic Vision Effect in Road Lighting Applications

Melanopic Limits of Metamer Spectral Optimisation in Multi-Channel Smart Lighting Systems

Indoor PV Modeling Based on the One-Diode Model

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