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Re: Halo Blue?
In a message dated 96-04-10 08:35:04 EDT, you write:
>
>Dear Tom,
>Halo blue is a fluorescent powder made of calcium fluorophosphate activated
>with
>antimony.
>It's exitation peak is at 220 nm, (so quite good for the production of a low
>pressure mercury discharge lamp) and it's emission peak is at a wavelength
of
>482 nm. The band width at 50% of it's relative energy is 138 nm and the band
>width at 25 % is over 200 nm namely from 400 till over 600 nm. The colour
>impression is therefore very lightblue (because of it's very width waveband)
>and
>quite pale (faded or washy, I don't know the right translation). As it is a
>halo
>phosphate the powder is not very stable and the colour output will be
lighter
>and lighter over the years. I think you can compare it with the colour that
>you
>call light blue, but now you also can compare it with other powders who have
>corresdonding wavelenght. It's a very soft blue with an emission line to the
>green and even to the yellow (10%) part of the spectrum. I have the powder
>here
>in stock, (Rotterdam) but I don't think you can handle our European method
to
>do
>the powdering yourself. If you need an ounce I can ship it to you through TL
>INC
>but I think that shipment is much more costly than the powder itself. The
>powder
>cost dFl: 76,-- (about $46.--) a quarter of a European kilo.
>Best from dirk a. boonstra
WOW, this is a subject I would like to hear more about! Not Halo Blue, per
se, but the subject of phosphors. Seems we have an expert in our midst, in
Dirk. Please give me more background, and I like it technical. Are there any
ways to learn more about the physics of phosphors? Can you give us some
recipes for coating phosphors, perhaps using the adhesive method recently
discussed by Tecnolux and others? Do you, in fact, have a catalog of phosphor
compounds? Are there any unusual colors not available in pre-manufactured
form we could get with some of the more exotic ones? Like to hear much more
about compositions and how they work. F-Centers and all that. Are there any
reference books on this subject for someone that can understand them and
appreciate it?
Jeff Golin
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