Correlated color temperature as an explicit function of chromaticity coordinates

McCamy, C. S.

doi:10.1002/col.5080170211

Cited by 1,632 publications

(422 citation statements)

References 8 publications

Supporting

Mentioning

407

Contrasting

Unclassified

Order By: Relevance

“…The following analytic equation, proposed by McCamy [19], was used for calculating the CCT of a light source with (x, y) coordinate in CIE 1931 chromaticity diagram: …”

Section: Discussionmentioning

confidence: 99%

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

Kim

et al. 2012

Journal of the Optical Society of Korea

View full text Add to dashboard Cite

For two well-known modulation methods, stepwise current modulation (SCM) and pulse width modulation (PWM), the effects of driving current modulation conditions on chromaticity were experimentally investigated in a white LED lighting system. For the experimental implementation of both SCM and PWM, a white LED lighting was fabricated using phosphor converted (PC) white light emitting diodes (LEDs) and a driving circuit module was developed. By using them, the variations of illuminance, color coordinates, and spectrum were evaluated under various forward current conditions. Through the analysis in color coordinates, yellow shift in SCM and blue shift in PWM were observed on chromaticity diagrams with increasing average driving current. In addition, in order to analyze color deviation quantitatively, color distance before and after current increase, and the correlated color temperature (CCT) were calculated. As a result, for the white LED lighting in both modulation conditions, the maximum difference in the calculated CCT was obtained close to 1000 K. It means that careful consideration is required to be taken in the design of illumination systems to avoid serious problems such industrial accidents.

show abstract

“…The following analytic equation, proposed by McCamy [19], was used for calculating the CCT of a light source with (x, y) coordinate in CIE 1931 chromaticity diagram: …”

Section: Discussionmentioning

confidence: 99%

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

Kim

et al. 2012

Journal of the Optical Society of Korea

View full text Add to dashboard Cite

show abstract

“…The efficiencies were directly calculated from the measured parameters, while the correlated color temperature (CCT) and color rendering index (CRI) values were analyzed by the built-in software of PR655, according to the CIE CRI method reported by McCamy. [16][17][18] III. RESULTS Figure 1 shows the luminance-current density-voltage (L-J-V) characteristics, the CIE coordinates, and the voltage dependent EL spectra of Devices 1, 2, 3, 4.…”

Section: Methodsmentioning

confidence: 99%

High performance flexible top-emitting warm-white organic light-emitting devices and chromaticity shift mechanism

et al. 2014

View full text Add to dashboard Cite

Flexible warm-white top-emitting organic light-emitting devices (TEOLEDs) are fabricated onto PET substrates with a simple semi-transparent cathode Sm/Ag and two-color phosphors respectively doped into a single host material TCTA. By adjusting the relative position of the orange-red EML sandwiched between the blue emitting layers, the optimized device exhibits the highest power/current efficiency of 8.07 lm/W and near 13 cd/A, with a correlated color temperature (CCT) of 4105 K and a color rendering index (CRI) of 70. In addition, a moderate chromaticity variation of (-0.025, +0.008) around warm white illumination coordinates (0.45, 0.44) is obtained over a large luminance range of 1000 to 10000 cd/m2. The emission mechanism is discussed via delta-doping method and single-carrier device, which is summarized that the carrier trapping, the exciton quenching, the mobility change and the recombination zone alteration are negative to color stability while the energy transfer process and the blue/red/blue sandwiched structure are contributed to the color stability in our flexible white TEOLEDs.

show abstract

“…2e) shows that the white light emission from the blue-LED based pcWLEDs containing a yellow phosphor has a higher CCT (7002 K) than that of the NUV-based one (4521 K), where the CCT values are calculated in terms of the chromaticity coordinates shown in Fig. 2e, based on the cubic approximation proposed by McCamy [16]. The CCT values here reveal that the light emitted from NUV-based pcWLEDs is perceived as warmer light than the one from blue-based pcWLEDs.…”

Section: Phosphor Converted White Light Emitting Diodesmentioning

confidence: 99%

Inorganic Phosphor Materials for Lighting

2016

View full text Add to dashboard Cite

This chapter addresses the development of inorganic phosphor materials capable of converting the near UV or blue radiation emitted by a light emitting diode to visible radiation that can be suitably combined to yield white light. These materials are at the core of the new generation of solid-state lighting devices that are emerging as a crucial clean and energy saving technology. The chapter introduces the problem of white light generation using inorganic phosphors and the structureproperty relationships in the broad class of phosphor materials, normally containing lanthanide or transition metal ions as dopants. Radiative and non-radiative relaxation mechanisms are briefly described. Phosphors emitting light of different colors (yellow, blue, green, and red) are described and reviewed, classifying them in different chemical families of the host (silicates, phosphates, aluminates, borates, and non-oxide hosts). This research field has grown rapidly and is still growing, but the discovery of new phosphor materials with optimized properties (in terms of emission efficiency, chemical and thermal stability, color, purity, and cost of fabrication) would still be of the utmost importance.

show abstract

Correlated color temperature as an explicit function of chromaticity coordinates

Cited by 1,632 publications

References 8 publications

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

Effects of Current Modulation Conditions on the Chromaticity of Phosphor Converted (PC) White LEDs

High performance flexible top-emitting warm-white organic light-emitting devices and chromaticity shift mechanism

Inorganic Phosphor Materials for Lighting

Contact Info

Product

Resources

About