The other is to use a phosphor
material to convert a monochromatic light from a blue or UV LED to a broad-spectrum white light, much in the same way as a fluorescent light bulb works [1-4].
Blue LED Source Spectrum, Excitation, and Emission Spectra of the Phosphors
. Figure 2 shows the excitation and emission spectra of the R-645, R-626, G-531, and G-529 phosphors
and the spectra of the pumping source for the experimental results.
It is a new technology and is the emission of light from a phosphor
material layer when an electric current is passed through it [7-11].
A team of scientists have found replacements for these scare elements: a green phosphor
that reduces the terbium content by 90% and eliminates lanthanum and a red phosphor
that completely replaces europium and yttrium oxide.
can be used in many different ways for a majority of lighting applications.
SEM Images of Synthesized Phosphors
. Figure 3 shows the Scanning Electron Microscope (SEM) images of powders prepared at 800[degrees]C.
The samples obtained in the experiment were marked as A-x, respectively, for the pressure impregnation procedure, where 'V indicates a phosphor
[([Ca.sub.1.5][Mg.sub.0.5]Sr) [O.sub.3] * [Al.sub.2][O.sub.3] * Si[O.sub.2]0.05B-0.01EuO * 0.005[Nd.sub.2][O.sub.3]] solution concentration of 0, 10, 20, 40, and 60wt%, respectively.
With the commonly used strontium aluminate phosphors
, the data from previous and present experimental work indicated that the last [[alpha].sub.i], rather than the last [[tau].sub.i], in an exponential equation is most strongly correlated with the afterglow characteristics of an object.
Yamamoto, "White LED phosphors
: the next step," in Optical Components and Materials VII, Proceedings of SPIE, 2010.
The longer a phosphor
stands after the excitation, the more trapped carriers will leave the traps, and the subsequently measured luminescence peaks will be weaker.
A high luminous flux of white light was realized through the development of a phosphor
material that is not subject to luminance saturation even when irradiated with high-intensity laser light.
Spectroscopic studies of these phosphors
play a vital role in characterizing the specific luminescence properties such as photoluminescence and thermoluminescence.