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Color temperature

About: Color temperature is a research topic. Over the lifetime, 8469 publications have been published within this topic receiving 96172 citations. The topic is also known as: colour temperature.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a room-temperature (RT) synthesis of CsPbX3@X quantum-well band alignment is proposed to guarantee the excitons generation and high-rate radiative recombination at RT.
Abstract: Recently, Kovalenko and co-workers and Li and co-workers developed CsPbX3 (X = Cl, Br, I) inorganic perovskite quantum dots (IPQDs), which exhibited ultrahigh photoluminescence (PL) quantum yields (QYs), low-threshold lasing, and multicolor electroluminescence. However, the usual synthesis needs high temperature, inert gas protection, and localized injection operation, which are severely against applications. Moreover, the so unexpectedly high QYs are very confusing. Here, for the first time, the IPQDs' room-temperature (RT) synthesis, superior PL, underlying origins and potentials in lighting and displays are reported. The synthesis is designed according to supersaturated recrystallization (SR), which is operated at RT, within few seconds, free from inert gas and injection operation. Although formed at RT, IPQDs' PLs have QYs of 80%, 95%, 70%, and FWHMs of 35, 20, and 18 nm for red, green, and blue emissions. As to the origins, the observed 40 meV exciton binding energy, halogen self-passivation effect, and CsPbX3@X quantum-well band alignment are proposed to guarantee the excitons generation and high-rate radiative recombination at RT. Moreover, such superior optical merits endow them with promising potentials in lighting and displays, which are primarily demonstrated by the white light-emitting diodes with tunable color temperature and wide color gamut.

1,932 citations

Reference EntryDOI
15 Jul 2005
TL;DR: In this article, the properties of inorganic LEDs, including emission spectra, electrical characteristics, and current-flow patterns, are presented and the packaging of low power and high power LED dies is discussed.
Abstract: Inorganic semiconductor light-emitting diodes (LEDs) are environmentally benign and have already found widespread use as indicator lights, large-area displays, and signage applications. In addition, LEDs are very promising candidates for future energy-saving light sources suitable for office and home lighting applications. Today, the entire visible spectrum can be covered by light-emitting semiconductors: AlGaInP and AlGaInN compound semiconductors are capable of emission in the red to yellow wavelength range and ultraviolet (uv) to green wavelength range, respectively. Currently, two basic approaches exist for white light sources: The combination of one or more phosphorescent materials with a semiconductor LED and the use of multiple LEDs emitting at complementary wavelengths. Both approaches are suitable for high efficiency sources that have the potential to replace incandescent and fluorescent lights. In this article, the properties of inorganic LEDs will be presented, including emission spectra, electrical characteristics, and current-flow patterns. Structures providing high internal quantum efficiency, namely, heterostructures and multiple quantum well structures, will be discussed. Advanced techniques enhancing the external quantum efficiency will be reviewed, including resonant-cavities, die shaping (chip shaping), omnidirectional reflectors, and photonic crystals. Different approaches to white LEDs will be presented and figures-of-merit such as the color rendering index, luminous efficacy, and luminous efficiency will be explained. Finally, the packaging of low power and high power LED dies will be discussed. Keywords: light-emitting diodes (LEDs); solid-state lighting; compound semiconductors; device physics; reflectors; resonant cavity LEDs; white LEDs; packaging

1,364 citations

Journal ArticleDOI
TL;DR: In this paper, a simple equation to compute correlated color temperature (CCT) from CIE 1931 chromaticity coordinates x and y is given, which is useful in designing sources to simulate CIE colorimetric illuminants.
Abstract: A simple equation to compute correlated color temperature (CCT) from CIE 1931 chromaticity coordinates x and y is given. Over the range of interest in color science, the errors are negligible. It was derived from the fact that the isotemperature lines for CCTs of principle interest nearly converge toward a point on the chromaticity diagram and the assumption that CCT may be represented by a third-order polynomial function of the reciprocal of the slope of the line from that point to the chromaticity of the light. the equation is useful in designing sources to simulate CIE colorimetric illuminants.

1,320 citations

Patent
18 Apr 2007
TL;DR: In this paper, a lighting device comprising first and second groups of solid state light emitters, which emit light having peak wavelength in ranges of from 430 nm to 480 nm, and the second and third groups of lumiphors which emit dominant wavelength in the range of from 555 nm to 585 nm.
Abstract: A lighting device comprising first and second groups of solid state light emitters, which emit light having peak wavelength in ranges of from 430 nm to 480 nm, and first and second groups of lumiphors which emit light having dominant wavelength in the range of from 555 nm to 585 nm. In some embodiments, if current is supplied to a power line, a combination of (1) light exiting the lighting device which was emitted by the first group of emitters, and (2) light exiting the lighting device which was emitted by the first group of lumiphors would have a correlated color temperature which differs by at least 50 K from a correlated color temperature which would be emitted by a combination of (3) light exiting the lighting device which was emitted by the second group of emitters, and (4) light exiting the lighting device which was emitted by the second group of lumiphors.

808 citations

Patent
09 May 2003
TL;DR: In this article, the authors proposed a method for providing power to devices via an A.C. power source, and for facilitating the use of LED-based light sources on a power circuit that provides signals other than standard line voltages.
Abstract: Methods and apparatus for providing power to devices via an A.C. power source, and for facilitating the use of LED-based light sources on A.C. power circuits that provide signals other than standard line voltages. In one example, LED-based light sources may be coupled to A.C. power circuits that are controlled by conventional dimmers (i.e, “A.C. dimmer circuits”). Hence, LED-based light sources may be conveniently substituted for other light sources (e.g., incandescent lights) in lighting environments employing conventional A.C. dimming devices and/or other control signals present on the A.C. power circuit. In yet other aspects, one or more parameters relating to the light generated by LED-based light sources (e.g., intensity, color, color temperature, temporal characteristics, etc.) may be conveniently controlled via operation of a conventional A.C. dimmer and/or other signals present on the A.C. power circuit.

622 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023107
2022246
2021282
2020415
2019549
2018534