Search results for "Color rendering index"

showing 2 items of 2 documents

Frequency-Downconversion Stability of PMMA Coatings in Hybrid White Light-Emitting Diodes

2015

We report on the properties of a poly(methyl methacrylate)-based coating used as a host for an organic dye in hybrid white light-emitting diodes. The device is composed by a pump source, which is a standard inorganic GaN/InGaN blue light-emitting diode (LED) emitting at around 450 nm, and a spin-coated conversion layer making use of Lumogen® F Yellow 083. Under prolonged irradiation, the coating exhibits significant bleaching, thus degrading the color rendering performance of the LED. We present experimental results that confirm that the local temperature rise of the operating diode does not affect the conversion layer. It is also proven that, during the test, the photostability of the orga…

Materials scienceInfraredSettore AGR/13 - Chimica Agraria02 engineering and technologyengineering.materialSettore ING-INF/01 - Elettronica01 natural sciencesCoating0103 physical sciencesMaterials ChemistryElectrical and Electronic EngineeringPhotodegradationDiode010302 applied physicschemistry.chemical_classificationSpin coatingbusiness.industryPMMA hybrid LEDs Lumogen polymer degradation photostability spin coatingPolymer021001 nanoscience & nanotechnologyCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsColor rendering indexchemistryengineeringOptoelectronics0210 nano-technologybusinessLayer (electronics)Journal of Electronic Materials
researchProduct

Warm white LED light by frequency down-conversion of mixed yellow and red Lumogen®

2013

This work reports on the benefits and promising opportunities offered by white LED hybrid technology, based on a mixing perylene-based dyes in order to obtain a warm white light for frequency-down conversion. In a standard Ce:YAG-based white LED, the white light appears cold due to the weakness of red wavelength components in the emission spectrum. In order to obtain a warmer white, one possible solution is to add a red phosphor to the yellow one to move the chromatic coordinates properly, though the luminous efficiency drastically decreases due to the increased light absorption of the coating layer. It is generally believed that the low efficiency of warm white LEDs is the main issue today…

Warm white LEDs hybrid LEDs perylene-based dyes Lumogen® LED optical characterization dip coatingMaterials sciencebusiness.industryPhosphorColor temperatureSettore ING-INF/01 - Elettronicalaw.inventionLuminous fluxColor rendering indexLED lampchemistry.chemical_compoundchemistrylawOptoelectronicsbusinessLuminous efficacyPeryleneLight-emitting diode
researchProduct