There Are many more parameters deciding about the use of a certain phosphor -

e.g. absorption spectrum, particle size distribution, stability in a package, price ....

What is the best phosphor to use ?

Is there one, Which fits all ?

Even experts have sometimes to change opinions.

We do.

What goes in to it ?  (just by process)

blue LED 

  • Forward voltage
  • Internal Quantum Efficiency
  • Outcoupling efficiency (to where?)

Conversion Process (one Phosphor, repeat for two, include interaction)

  • Absorption of Blue (Color Balance)
  • Quantum Efficiency
  • Quantum Deficit
  • Outcoupling - Package Efficiency
  • Lumious Efficacy of the final spectrum


There is NO one-fits-all Phosphor

Not only are more and more phosphors invented, discovered, tailored, modified but more and more lucrative Applications become known. 

One of the latest developments is the fully-phosphor-converted LED to make good for the efficiency gap of LEDs in the yellow-orange spectral range. So as long as the InGaN LEDs do not better in that range, narrow band phosphors are highly wanted.

Phosphor production went down world-wide with the demise of the CRT 15 years ago. Only very few factories survived. Today the number of phosphor makers is estimated to have climbed to >50, many of them not only competing on price. And as they rely on rare earth dopants, especially Eu supply is vital, pushing this industry ahead.

The way phosphors are applied influences the selection of phosphors, which can be taken into account - remote phosphor applications are the best known examples. 

And how do you measure ANY or all of those ?

Regina Mueller-Mach / Gerd O Mueller © ALL RIGHTS RESERVED.

from phosphor selection to color gamut:

the other way round is much more difficult and not unique; 

many parameters have to be known or determined to do the job. We do..


Why is your lumen per Watt value so low ?

What is low/high ?

Even experts have sometimes to change opinions.

We do.