Luxeon Star LED's

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Hi,

I am very interested in those Luxeon Star LED's.  I've never used one
before, but I've read some very interesting things about them, and I am
thinking about using one in my project.

I have a few questions about them (info which I can't seem to find on the
net):

1)  For those of you who have used one, are they worthwhile?  Are they
really that bright?

2)  I currently have a high brightness white 12-LED Globe from Jaycar
Electronics (see link).
http://www1.jaycar.com.au/productView.asp?ID=ZD0304&CATID=&keywords=zd%2D0304&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID =
The brightness of this LED globe is quite good, but I want brighter!  How
would the brightness level of this compare to a 1W, 3W and 5W Luxeon?  I am
only used to "MCD" type measurements, not "lumens" per watt.
The Silicon Chip website shows two projects where luxeons are used outdoors
at night... Surely they can't be *that* bright?!

3)  If I was wanting to power up a 3W or 5W Luxeon Star, what would be the
most *simple* power supply I can connect to it that would fit nicely into a
UB5 Jiffy Box (83L x 54W x 31D mm) - including the luxeon heatsink?  I've
seen some luxeon drivers around on the web but they seem too big in size for
my project, probably because they include special functions like low battery
drain, low power cut-off, brightness control, etc (features I don't need
which take up board space right?)..  Note that I will be connecting a *12V
power adaptor* to it (as opposed to a battery), so I won't need most of
those features.  The smaller the driver circuit, the better =)    Any ideas?

Thanks in advance,

Jason.






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http://www1.jaycar.com.au/productView.asp?ID=ZD0304&CATID=&keywords=zd%2D0304&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID =
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Lumen is total light output. It is like saying "equivalent to a
so-and-so many watt lamp". Not that Lumpens match watts, but you get the
idea. A 10 watt lamp can be in a reflector in which case it is very
bright in one direction, or it is not and it is rather weak in all
directions.

MCD is millicandela which is candlepower. It is how bright it shines.
The more directed the higer the MCD or candela rating. That is why
ultra-bright LEDs hardly can be seen from the side.

Now back to the Luxeon: compare the power input of the LEDs for
comparison. You have 12 LEDs now at 30 mA each at 3.something volt each.
That is just above a watt. You can expect the Luxeon 1 watt to be in
that ballpark. But the Luxeon will radiate in a wider pattern I think.


Thomas

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http://www1.jaycar.com.au/productView.asp?ID=ZD0304&CATID=&keywords=zd%2D0304&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID =
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Thanks Thomas for answering question 2 for me.
So what you're saying is a 1W Luxeon would be *about* the same brightness as
the LED globe I have?  Hmmm.  I think I'll need to aim for 3W luxeon (would
that mean up to 3 times brighter than 1W?  Sorry, dumb question, lol).

Now I just need help on question 3 from somebody.  =)

Regards,
Jason



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http://www1.jaycar.com.au/productView.asp?ID=ZD0304&CATID=&keywords=zd%2D0304&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID =
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I think I found something....  http://www.cutter.com.au/products.php?cat12 %




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http://www1.jaycar.com.au/productView.asp?ID=ZD0304&CATID=&keywords=zd%2D0304&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID =
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Almost certainly not.
I have a Jaycar 12led headlamp and a proper Princeton Tec EOS 1W
headlamp.
The Princeton tec EOS blows the Jaycar out of the water.
The EOS for example can easily light up a 30m high waterfall at night
from about 30m away, the Jaycar throws a very dim light by comparison.
The EOS does have a proper designed reflector though, designed for long
throw with a mild dispersion pattern. The Jaycar is simply the LEDs on
their own with a wide pattern, the reflector in it does nothing.
You can get the Star with or without a built in reflector/lense I
believe, and that will make a great difference depending on the
application.

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Essentially, yes.

What do you want to use it for?
 
Dave :)


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Hi Dave, thanks for your input.

I want to use it for a disco light - The light beam will just be thrown
around in a dark room at various speeds (will be used with a pan/tilt module
I am working on).  =)   .... with other lighting and party fog, of course!
I will be using collimating lenses with the star to get a nice, sharp beam.
I want to adapt LED technology and try and get away from the incandescent
stuff.

I can see you can get *coloured* stars!  Only seen 1W and 3W ones.  I wonder
if you can get 5W ones as well.

Jason.



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Sounds like fun!

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For indoor use in the dark at close range I'd suggest that the 1W would
be plenty. The 1W is terribly blinding if you look directly into it, I
can't imagine what the 3W or 5W would be like. The 1W is much cheaper
too of course.

If you are pulsing the LED with a long off duty time then you can
probably get away with a much smaller heatsink than recommended.

Now I'm thinking a modified spinning disco ball with a 100 x 1W Stars -
that would be something!

Dave :)


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That might be true, but I'd rather too bright than not bright enough... I
will probably go for the 3W.  I am thinking 5W would be too bright too.
Pretty expensive anyway.

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Well, now that you mention it, I wil be using both methods.... steady and
strobing.  Will therefore need to use the recommended heatsink for steady
mode.

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LOL!  That would be very fiddley!

Jason.



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The 5 watters have a bit less efficiency. I really never heard of the 3 watters.
The star has a wide dispersion and the lens that fits over it
will concentrate the beam. I allready thought of the disco light
while playing with these. I have 9- 5 watters right now, just the emitters,
no attached sink from Luxeon. It too bright to look at without any concentration.
I can pulse up to 65 watts withg this setiup.

greg


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Thanks Greg,
I am definately using lens to concentrate the beam (probably the 15 or 25
degree), and nobody's gonna get a chance to stare into it because the beam
is going to be moving quickly, and needs to be bright enough to be noticable
in party fog.  Being LED and all, I wasn't sure if 1W was going to be strong
enough, thus the thoughts of a 3W =)
1W not bright enough?  5W too bright?  What about 3W?  LOL.

Jason.





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Right now I am going to try and remove Leds epoxied to copper
without damage. Wish me luck. I need to reposition the Led's.
The epoxy is kinda thin since I sprinkled diamond dust in it.

greg

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haha, well, good luck! =)
why are you removing them again?

Jason



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I have them currently spaced so there is no clearance between them.
I am going to use fiber optic to couple 9 into 1 light source.
I also use a peltier devive to pump heat out faster from the Led's,
and from the copper to aluminum CPU heatsink and fan.

greg

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LXHL-PM02

I need 9 or 10 of these ASAP. ???

I tried taking the things off the sink. Amazing the way they are made.
I tried heating the sink to 150 F so the epoxy stuff softems.
Well everything softens. The metal bottom piece is attached to a wafer
with some kind of glue or epoxy. Some kind of sparkly stuff also, which
looked like dimonds, but I believe there is no electrical insulation between
the wafer and sink. This little sink is mated with the larger aluminum
sink sold as a star. With the little sink and attached wafer on the bottom, a gel
like material in between the wafer and top clear plastic envelope. The
connections are
made and a plastic outer rim is then attached.

I have a 6 week 50 min order to make unless I can find a interim supplier.

greg
 

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I just ran across the Phillips Luxeon K2 series. Anybody know
anything about these. They seem cheaper than others, but
I have not mad total comparisons.

greg

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GregS wrote:

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They do what the datasheet(s) say they do.
The data from Lumileds is fairly comprehensive on the luxeons

The K2's are desiged to compete with (particularly) the Cree and Osram
'power' white leds - maybe Seoul Semi should also now be included.


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I understand they are new, and most are not yet available.
The amazing thing I'm looking at. The Blue K2 is up to twice as bright as blue
Type V's.
I am not using white at all. I am just using green and blue, and the current V
types
have 3 times the Lumens as the blue. However the Lumens on the other color
type K2's did not grow as much, or are less.
The blue LED's have an extremly high output when compared to most other types
of illumination, halogen, arc, etc, after filtering.

greg
 

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  They do exist, not for all colors, and price increases more than
performance for most applications.

  Keep in mind that 3W Luxeon has same chip size as 1W but 5W has a 2x2
array of same size chips - making any collimated beam up to twice as wide
(or twice as blurry).

 - Don Klipstein ( snipped-for-privacy@misty.com)

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  "1 watt" Luxeon when used "as directed" most typically consumes 1.2
watts.  The latest white ones that I know of supposedly typically produce
45 lumens when used that way when colled sufficiently for chip junction
temperature of 25 degrees C, which requires heatsink slug surface
temperature mabe 7-8 degrees C.  Expect light output about 6% less with
temperature 18 degrees C warmer than that.

  The "3 watt" white ones in comparison with the more typical 700 mA drive
current typically consume 2.6-2.7 watts and produce 65 lumens of light
when doing so when cooled sufficiently to have their chip junction
temperature 25 degrees C. requiring the surface of the LED's heatsink slug
to be cooled to about -9 to -10 degrees C.  Expect with temperature 40
degrees C warmer, light output to be about 14% less.
  80 lumens is typically achievable from white "Luxeon III" at 1 amp, with
typical voltage drop 3.9 volts so power consumption would typically be 3.9
watts.  Again, this is with cooling sufficient to have the junction within
the chip at a temperature of 25 degrees C, and the heatsink slug surface
of the LED needing to be cooled to about -25 degrees C to achieve that.  
At 50 degrees C warmer than that, expect light output about 18% less.

  Based on how I see the DS25 and DS45 datasheets from Lumileds...

 - Don Klipstein ( snipped-for-privacy@misty.com)

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Thanks for the info Don.
Hmmm, these things are starting to remind me of the charging of bloody SLA
batteries when you talk about temperature and heatsinks and stuff!  Jaycar
Electronics have got these 'Heatsink Pin Grid Array with adhesive thermal
transfer tape' (CAT HH-8580).  These wouldn't be sufficient for 3W stars?
Its says it has a thermal resistance of 5.9 degrees celcius per watt.  If
not, what if I add a small cooling fan as well?  Trouble is, all of this
needs to fit into an ABS box (will be ventilated of course) size approx 83L
x 54W x 31D, but all the electronics will be in another box close by.  What
do you suggest?  I've never used these things before.

Regards
Jason.



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