Analysis of circadian properties and healthy levels of blue light from smartphones at night DOI Creative Commons

Ji Hye Oh,

Heeyeon Yoo,

Hoo Keun Park

et al.

Scientific Reports, Journal Year: 2015, Volume and Issue: 5(1)

Published: June 18, 2015

Abstract This study proposes representative figures of merit for circadian and vision performance healthy efficient use smartphone displays. The recently developed luminous efficacy radiation (CER) illuminance (CIL) related to human health rhythm were measured compare three kinds commercial CIL values social network service (SNS) messenger screens from all displays higher than 41.3 biolux (blx) in a dark room at night the highest value reached 50.9 blx. These corresponded melatonin suppression (MSVs) 7.3% 11.4%, respectively. Moreover, bright had much MSV (58.7 ~ 105.2 blx 15.4 36.1%, respectively). also analyzed nonvisual visual optical properties while varying distance between screen eye controlling brightness setting. Finally, method possibly attenuate unhealthy effects was proposed investigated by decreasing emitting wavelength blue LEDs LCD backlight subsequently reducing effect display.

Language: Английский

A novel single-phase white light emission phosphor for healthy lighting, anti-counterfeiting, and plant lighting DOI
Yunfei Li, Shengda Liu, Yuqi Wang

et al.

Journal of Molecular Structure, Journal Year: 2025, Volume and Issue: unknown, P. 141430 - 141430

Published: Jan. 1, 2025

Language: Английский

Citations

2
Study of Perovskite QD Down-Converted LEDs and Six-Color White LEDs for Future Displays with Excellent Color Performance DOI

Hee Chang Yoon,

Heejoon Kang,

So‐Young Lee

et al.

ACS Applied Materials & Interfaces, Journal Year: 2016, Volume and Issue: 8(28), P. 18189 - 18200

Published: June 28, 2016

A narrow-emitting red, green, and blue (RGB) perovskite quantum dot (PeQD)-based tricolored display system can widen the color gamut over National Television System Committee (NTSC) to 120%, but this value is misleading with regard perception of cyan yellow reproduced in narrow RGB spectra. We propose that a PeQD-based six-color reproduce true-to-life spectral distributions high fidelity, gamut, close gap by adding (Cy), yellowish green (Yg), orange colors (Or). In study, we demonstrated pure-colored CsPbX3 (X = Cl, Br, I, or their halide mixtures; Cl/Br Br/I) monochromatic down-converted light-emitting diodes (DC-LED) for first time, incorporated PeQDs UV-curable binders long-wavelength-pass-dichroic filters (LPDFs). pure Cy-, G-, Yg-, Or-, R-emitting DC-LED provide luminous efficacy (LE) values 81, 184, 79, 80, 35 lm/W, respectively, at 20 mA. also confirmed suitability possibility access future color-by-blue backlights field-sequential-color liquid crystal displays, using multipackage white LEDs, as well six-colored devices vision performance. The fabricated LEDs exhibited an appropriate LE (62 lm/W total 120 mA), excellent qualities (color rendering index (CRI) 96, special CRI red (R9) 97) correlated temperature (CCT) 6500 K, wide covering NTSC up 145% 1931 Commission International de l’Eclairage (CIE) coordinates space.

Language: Английский

Citations

168
Synthesis of narrow-band red-emitting K2SiF6:Mn4+ phosphors for a deep red monochromatic LED and ultrahigh color quality warm-white LEDs DOI

Ji Hye Oh,

Heejoon Kang,

Yun Jae Eo

et al.

Journal of Materials Chemistry C, Journal Year: 2014, Volume and Issue: 3(3), P. 607 - 615

Published: Nov. 19, 2014

In this study, we synthesized and characterized narrow-band red-emitting K2SiF6:Mn4+ phosphors in order to improve the color qualities of warm white light-emitting diodes (LEDs).

Language: Английский

Citations

159
Blue-Emitting K2Al2B2O7:Eu2+ Phosphor with High Thermal Stability and High Color Purity for Near-UV-Pumped White Light-Emitting Diodes DOI
Wenge Xiao, Xia Zhang, Zhendong Hao

et al.

Inorganic Chemistry, Journal Year: 2015, Volume and Issue: 54(7), P. 3189 - 3195

Published: March 9, 2015

Novel blue-emitting K2Al2B2O7:Eu2+ (KAB:Eu2+) phosphor was synthesized by solid state reaction. The crystal structural and photoluminescence (PL) properties of KAB:Eu2+ phosphor, as well its thermal the photoluminescence, were investigated. exhibits broad excitation spectra ranging from 230 to 420 nm, an intense asymmetric blue emission band centered at 450 nm under λex = 325 nm. Two different Eu2+ centers in confirmed via their fluorescence decay lifetimes. optimal concentration ions K2–xEuxAl2B2O7 determined be x 0.04 (2 mol %), corresponding quenching mechanism verified electric dipole–dipole interactions. PL intensity nonoptimized KAB:0.04Eu2+ measured ∼58% that commercial BaMgAl10O17:Eu2+ this has high color purity with CIE coordinate (0.147, 0.051). When heated up 150 °C, still 82% initial room temperature, indicating stability. These results suggest is a promising candidate n-UV convertible for application white light emitting diodes.

Language: Английский

Citations

151
Analysis of circadian properties and healthy levels of blue light from smartphones at night DOI Creative Commons

Ji Hye Oh,

Heeyeon Yoo,

Hoo Keun Park

et al.

Scientific Reports, Journal Year: 2015, Volume and Issue: 5(1)

Published: June 18, 2015

Abstract This study proposes representative figures of merit for circadian and vision performance healthy efficient use smartphone displays. The recently developed luminous efficacy radiation (CER) illuminance (CIL) related to human health rhythm were measured compare three kinds commercial CIL values social network service (SNS) messenger screens from all displays higher than 41.3 biolux (blx) in a dark room at night the highest value reached 50.9 blx. These corresponded melatonin suppression (MSVs) 7.3% 11.4%, respectively. Moreover, bright had much MSV (58.7 ~ 105.2 blx 15.4 36.1%, respectively). also analyzed nonvisual visual optical properties while varying distance between screen eye controlling brightness setting. Finally, method possibly attenuate unhealthy effects was proposed investigated by decreasing emitting wavelength blue LEDs LCD backlight subsequently reducing effect display.

Language: Английский

Citations

148