White LED Lighting... was RE: Re: ADSL vs Cable

["paul_watkin" <paul_watkin@xxxxxxx>]

The different intensities are due to the technology used to develop 
the white light.

Most of the LED's on the market start with a blue LED and then use a 
one or two phosphour system to produce the white (the phosphour 
actually goes in the epoxy).

Nichia who were originally a chemical company making phosphours found 
this affect first and have some pretty good patents for the 2 
phosphour system, which they rigidely enforce

When using these things be careful that you get the current through 
them similar and if you can, get them to supply devices from one Vf 
bin otherwise you might find your wall has various different shades 
of white as you move along it!

At 20mA these things will be white at 5mA they are likely to be blue, 
to give you an idea of the extremes

Paul 

--- In ukha_d@y..., "Ian Lowe" <ian@w...> wrote:
> It does, doesn't it...
> 
> well, I have contacted computronics for some more details.
> 
> Looking at 12Candela 5mm LEDs in a water clear package. forward 
current is
> 30mA, voltage nominally 3.6V, and 22 degree half power angle..
> 
> Cost is A$820 AUD, about ?305 GBP so far but I have asked about 
multiples..
> 
> in the meantime, if anyone finds a UK/EU source, holler please ;)
> 
> Ian.
> 
> -----Original Message-----
> From: Scott Crowther [mailto:scrowther@i...]
> Sent: 24 April 2002 10:09
> To: 'ukha_d@y...'
> Subject: RE: White LED Lighting... was RE: [ukha_d] Re: ADSL vs 
Cable
> 
> 
> sounds like a bulk buy to me...
> 
> 
> 
> Scott Crowther
> Intamac Systems Ltd
> 
> t: +44 (0)1604 679262
> e. scrowther@xxxxxxx
> w. www.intamac.com
> 
> 
> -----Original Message-----
> From: Ian Lowe [mailto:ian@w...]
> Sent: 24 April 2002 10:00
> To: ukha_d@xxxxxxx
> Subject: RE: White LED Lighting... was RE: [ukha_d] Re: ADSL vs 
Cable
> 
> 
> yeah,
> 
> I found a company in korea doing MR14 MR16 sized replacements for 
the small
> Lv Halogens, in 20W equivelants. These were clusters of 15 LEDs, 
each
> producing about 3Cd..
> 
> Since digging more and more, I found a maglite like torch quiting a
42
> Candela output in white, using THREE LEDs!! it was also 100,000 
year (Ten
> Years continuous use) LED life, and about 100 hours on three AA 
cells..
> 
> so I had a further rummage, and found what I believe to be the 
highest rated
> white LEDS available on the market now...
> 
> 12 Candela units, from computronics in Australia. (they are selling
a bag of
> 500 for about ?300 + shipping)
> 
> The bizzare thing for me is this:
> 
> the 2500mcd ones use 20mA at about 3.8V optimal..
> 
> And the 12000mcd ones, despite being nearly five times brighter 
use, er,
> 20mA at about 3.8V
> 
> I'm totally smitten!!
> 
> The idea of having a cool crisp light (I like a slight blue tint at
the best
> of times, so the lack of any "red" component doesn't bother
me) 
that can be
> used with normal usage patterns for 25 years and uses about
>ONE< 
Watt in
> place of a 50W Halogen, whilst producing an equivelant 80W light 
level is
> pretty amazing..
> 
> I'm having ideas of totally cool under cupboard lighting, but 
having twice
> as much light for about 4% of the leccy... :)
> 
> more research required...
> 
> as an aside, if we don't get a European supplier, is anyone 
interested in
> chipping in for some of the LEDs from Computronics. I think it 
works out at
> about 60p each. ?
> 
> Ian
> 
> 
> 
> -----Original Message-----
> From: paul_watkin [mailto:paul_watkin@y...]
> Sent: 23 April 2002 20:31
> To: ukha_d@xxxxxxx
> Subject: White LED Lighting... was RE: [ukha_d] Re: ADSL vs Cable
> 
> 
> Nichia have the brightest white LED's on the market at about 6.4cd
in
> a T1 3/4 package or 3.2cd in T1
> 
> http://www.nichia.co.jp
> 
> Not sure who in Europe holds a disty franchise for Nichia though, 
try
> Arrow, EBV somebody like that. I'll try and find out who it is
> tomorrow.
> 
> Other companies to look at are Panasonic, Lumiled (Agilent and
> Philips Joint venture to replace the lightbulb with led's) and
also
> Agilent Technologies.
> 
> Although you would probably need an account with somebody like
Arrow
> or EBV to get access to stuff from the above suppliers.
> 
> Regards
> 
> Paul
> 
> --- In ukha_d@y..., "PatrickLidstone" <patrickl@t...>
wrote:
> > >
> > > Due to really awful search functions (and every
electrical
> appliance
> > > containing LEDs), I can't find details.  There is a 3mm
LED on
> the
> > Maplin
> > > site
> > > (http://maplin.co.uk/products/details.php?
> > cartid=0204231835361451415&modulec
> > > ode=&moduleno=17821&manufacturer=Nichia).  I
based my thoughts 
on
> > the
> > > variety of LED torches around.
> >
> > Rapid Electronics do a separate opto-electronics catalogue -
> probably
> > worth a gander.
> >
> > You'll find full tech specs on RS (Radio Spares) and Farnell
> websites
> > for a huge range of LEDs.
> >
> > Patrick
> 
> 
> 
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