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Subject: Re: [Homebrew_PCBs] Re: For a DIY exposure box ... is collimated light an issue?

From: brane2 <brankob@...>
Date: 2013-07-06

I've just finished purchasing some of the material for our first
non-improvised lamp.

I plan to use Osram's bactericidal fluo lamp Puritec 15W:

http://www.osram.com/appsinfo/pdc/pdf.do?cid=GPS01_1028570&mpid=ZMP_1008467&vid=EU_ALL_eCat&lid=EN

I plan to use 6 of them in front of simple reflector, made of 1-2mm
aluminuim sheet, covered with adhesive mirror foil ( as used in
aquariums etc). Metal sheet will have edges ( like last 10 cm or so on
each side) bent at an angle 45° and I plan to kill non-vertical rays
with black cardboard mesh in front of reflector.

Flo lamps are EUR9/pc, electronic ballasts are EUR15 or so. I planned to
repurpose PC's PSU for that and ouple other things, but colleague has
already brought a couple of them with lamps, so I might just buy a
couple more and use them instead...








Dne 06. 07. 2013 14:35, pis(e arvidj01:
>
> --- In Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>, James <bitsyboffin@...> wrote:
> >
> > On 06/07/13 15:05, arvidj01 wrote:
> > >
> > >
> > > Any thoughts based on your experiences would be appreciated,
> including
> > > "Your are over thinking this! Just build the d..n box.".
> > >
> >
> > For hobby purposes, this.
> >
> > If you use LEDs, just do a quick check that your led spacing and
> > distance to your artwork from the leds does not introduce dead spots,
> > that is, make sure the viewing angles of adjacent LEDs overlap at or
> > just before the artwork.
> >
> > Dead spots will make the box useless for everything, while poor/no
> > collimation won't have an effect unless you're really pushing the
> > boundaries of hobby exposure in my opinion.
>
> The UV LED's on eBay seem to come in two flavors:
>
> narrow angle, about 20 to 25 degrees
>
> wide angle, about 150 to 160 degrees
>
> It would seem like the wide angle version would mitigate the dead spot
> issue at the expense of needing more LED's to make up for the lack of
> focus ... no pun intended ... of the energy by the wide angle.
>
> My thought is that a large number of wide angle LED's would provide a
> very even ... but also extremely non-collimated ... UV source.
>
>



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