White LED questions

[ID_Paul]

I am new to the world of LED lights, I just got my first one and am suddenly seeing all sorts of possibilities for this technology.

Some projects I have in mind would benefit from white LED light sources, but I know nothing about them - where to buy, what specs to look for, etc.

My questions:
1. If I want the brightest, widest angle white LED out there, what specs do I look for?

2. Where is a good source to buy them?

3. How does the light output from a good white LED compare to a mini xenon incandescent bulb?

Thanks,
Paul

 

[MicroE]

Paul---Welcome. On CPF you will meet a lot of Flashaholics that know their stuff. There are experts here on almost everything. I'm here to learn from the experts.
1.) The brightest White LED is the Lumileds Luxeon Star. The 1Watt units are in production and work very well. Luxeon has recently launched the 5 Watt White units but they have long lead times and short (1,000 hours) lives.
2.) Luxeon stars can only be purchased through FutureActive or here on CPF (try the Buy/Sell/Trade Forum. http://www.futureelectronics.com/1033/promos/lumileds/
3.) For color this is debatable. My experience is that the Luxeons are much whiter than an incandescent bulb. All of my bulbs look yellow when compared to the white Luxeons.
For throw and power incandescents have a big edge. If you want a light that will throw you should buy a good incandescent. Some CPF members are building Luxeon lights that have very good throw, but they still pale in comparison to incandescents when comparing beam throw.
Now I'll let other people expand on these "brief" comments.----Marc

 

[Lux Luthor]

Originally posted by MicroE:
...Luxeon stars can only be purchased through FutureActive or here on CPF (try the Buy/Sell/Trade Forum. http://www.futureelectronics.com/1033/promos/lumileds/...

<font size="2" face="Verdana, Arial">Some of their models are also available from markhannahsurplus and theledlight.

 

[Charles Bradshaw]

Check that markhannasurplus link, Lux. In roadrunner ISP, it does not exist.

Welcome to CPF, Paul.

 

[Lux Luthor]

Fixed it.

 

[Charles Bradshaw]

Thanks, Lux. Now I have it bookmarked.

 

[ID_Paul]

Thank you for the replies. Sorry I didn't get back here sooner.

Paul

 

[INRETECH]

There are basically three different types of LEDs on the market today:

1) T1-3/4 (5mm)
Typical LED, 20ma, output to approx 7cd

2) SPIDER (4 leg)
Square LED, 75ma, output to approx 50cd

3) Luxeon (Special package)
Round LED, 350ma 1W or 750ma 5W
Output approx 200-350cd (bright)
Proper heatsinking required

It depends on your application, and pocketbook

When looking at the bright of a LED, be carefull the beam width; there are some 15cd 5mm LEDs out there - but they have a 1-5d beam width; they simply take all their energy and put it into a very tight beam

Lumens are a more accurate means of measuring light output, but not all companies will give them

 

[INRETECH]

There are basically three different types of LEDs on the market today:

1) T1-3/4 (5mm)
Typical LED, 20ma, output to approx 7cd

2) SPIDER (4 leg)
Square LED, 75ma, output to approx 50cd

3) Luxeon (Special package)
Round LED, 350ma 1W or 750ma 5W
Output approx 200-350cd (bright)
Proper heatsinking required

It depends on your application, and pocketbook

When looking at the bright of a LED, be carefull the beam width; there are some 15cd 5mm LEDs out there - but they have a 1-5d beam width; they simply take all their energy and put it into a very tight beam

Lumens are a more accurate means of measuring light output, but not all companies will give them

 

[txwest]

And you wanted it as wide a beam as possible??? Well take the optics off the Luxeon & you'll get about 180 degrees. TX

 

[James S]

I have a very limited experience with Luxeons, but the green color around the edges is very prominent in the 3 or them I've played with. So much so that I would not want to use them for regular lighting. I do understand that some people have gotten them that are great with no green, but you can't order just a couple that way.

Does anyone have sources for the square spider LED's? I'd like to experiment with those a bit too.

Thanks,
James

 

[INRETECH]

You can get the Square Spider LEDs from several companies - but the most common is HP/Agilent/Lumileds

www.lumileds.com

 

[The_LED_Museum]

You can also get them from Vishay at http:/www.vishay.com as well.

 

[INRETECH]

We have the Square/Spider LED in Red/Orange
Its bright !!

Craig, nice to see you're back
I like to call you, send your contact information
to [email protected]

 

[McGizmo]

Hello ID_Paul,

I'd like to add two other types of LED's to Inretech's list, especially if you are looking for GOOD widea angle beams. There are T1 which are 3 mm LED's and I for one have found that the Nichia 312 gives a great and consistant beam of roughtly 70 degrees. There are also SMD LED's by Nichia and others that are very small and have extremely wide beam spreads.

- Don

 

[INRETECH]

I did another posting on another thread, and did list the other two sizes

I don't use the SMD and T1 much, they are so small and don't put much light compared to the other choices

I have a piece of vectorboard with about 40 different types of LEDs (color,size,shape) that I take out and show when I do the LED class here in town

 

[McGizmo]

Mike, as you mentioned, it would be nice if manufacturers listed the lightoutput in lumens. If they did, I believe you would find that the NSPW312BS, a white 3 mm LED from Nichia puts out as many photons as the 5 mm which afterall, have the same die; just more epoxy envelope around them (more light loss).

- Don

EDIT: I base my statements on information from two sources employed by Nichia.

 

[INRETECH]

Yes, very very true; using Lumens would be much better

So many companies like listing them in Cd, then they can put on a lens and make the numbers look really good

I have a sample of a 14cd Orange LED, and it must have a beam width of about 1/2-degree; its just a normal die with a MONGO 0.520 inch diameter lens on it - I don't know who made it; my friend Brian brought it back from Japan

But, having the different types of cases is a big advantage, sometimes you need a narrow beam and other times wide angle

My artist friend purchased 500 SuperBright KingBright Green LEDs for:

http://www.tri-met.org/max/yellowline/stationart/rosequarterart.htm

Its VERY common for a company to make a LED die-holder-lead and then package it in several different cases/lenses