Brightest Blue LED on a budget

[blasterman]

I have a project where I have to do a lot of illumination with blue (not royal) LEDs.

Looking at specs, it seems the Rebel (high current version) is the winner at 48 lumens. The triple Rebel stars are too expensive, and optics too limited.

Other options I should be looking at? Anybody know a source that actually has the blue Rebel on star in stock?

 

[StarHalo]

LEDs are expert at emitting a huge amount of their total output as just blue light (since white LEDs are actually blue begin with.) This means using a blue filter works very well; If you're looking to go truly cheap, any high-output cool-white LED with a blue lens will yield excellent results.

 

[blasterman]

Makes Sense....

Source of blue filters for such an application?

 

[StarHalo]

In the low-budget spirit, I'd go with a craft store. Some sheets of transparent blue plastic pages.

 

[blasterman]

Problem is that plastic filters or theater gels eventually fade requiring replacement. These LEDs will be installed in a location that I'm not going to appreciate having to replace every 6 month.

 

[Marduke]

Just use a blue Cree XR-C. It is a direct replacement for any light which already uses the XR-E or XR-C with 350-mA or less current.

Something like this.

 

[blasterman]

Why should I use the Cree over the Rebel?

 

[Changchung]

Why should I use the Cree over the Rebel?

The triple Rebel stars are too expensive, and optics too limited.

I have use cree blue Leds so far... This Leds rocks...

 

[R33E8]

LEDs are expert at emitting a huge amount of their total output as just blue light (since white LEDs are actually blue begin with.) This means using a blue filter works very well; If you're looking to go truly cheap, any high-output cool-white LED with a blue lens will yield excellent results.

I think using a blue led would be cheaper and brighter... you loose light from the phosphor and the phosphor in white leds is usually the most expensive part...

 

[2xTrinity]

I think using a blue led would be cheaper and brighter... you loose light from the phosphor and the phosphor in white leds is usually the most expensive part...

Three reasons why a filtered white will have FAR less visible blue output than a blue device:

1) White LEDs use 450nm blue, as opposed to 470nm blue like the LED at DX, this means even without any phoshpor losses, the deeper blue will appear dimmer.
2) The phosphor will absorb most of the 450nm blue light
3) No external filter has a sharp cutoff, you will either let in a lot of the phosphor emissions (giving you a cyan color), or attenuate a lot of the blue (leading to even worse efficiency).


Most importantly, I can't think of any high power white LEDs actualy cheaper than the blue ones from DX...

 

[Stillphoto]

Well if you decide to use white and gel the lights, gels for the film/photo industry are made specifically to withstand fading. Many shades of blue, and for 5 or 6 bucks you can get a huge sheet of it...

But yeah I still think blue leds would be easier.

 

[mds82]

http://ledlightingsupply.com/ledlightingsupply/XLamp Blue LED Closeout sale.htm

there is a sale for less then $2 per device. I'm not sure what the minumum order $$ is though.

 

[blasterman]

{groan}

My original post inquired as to the Rebel having 48Lm as advertised, which meets my needs.

I realize this forum is heaviy biased towards DX, flashlights/toys, and Cree, but there are emitters out there other than Cree. None of the Crees mentioned here have near the rated Lm as the Rebel.

(1) Has anybody used the specific 48Lm Blue Rebel in question?
(2) Does anybody know if it really does have those rated specs?
(3) I'm not interested in the three emitter Rebel because it's too expensive.
(4) I'm not building a flashlight, but using them for a commercial installation
(5) I'm not using colored gels on a white LED because I don't feel like climbing a 14' ladder twice a year and replacing colored plastic filters on an LED 18' over the floor.
(6) I don't want to deal with bare Rebel emitters.

I'd appreciate it if somebody could offer information related to my original question.

 

[industry7]

So this thread is pretty much exactly what I'm looking for; high efficiency blue LEDs that won't break the bank. The last post in this thread was 6 months ago, and it seems like there has been a lot of advancement in the field since then. So what's out there right now?

Cree keeps announcing new high efficiency white, the latest I think was something like 160lm/W. It seems like blue should be even better since you don't have losses in the phosphor, but I don't know what's actually available right now, as opposed to all the news making LEDs that are still a couple years from market.

 

[greenlight]

Can't you guys be a little less vague about your projects?

 

[industry7]

Can't you guys be a little less vague about your projects?

Ok... what specific info do you want? The specific color of blue I need my lights to be is about 450-460nm. Other than that, my chief concern is overall luminous efficacy, since the savings in operational cost over the course of the LED's lifetime should far outweigh the initial investment (isn't that the entire point of going to LED?).

Other than that, I'm too much of a noob to even guess at what other info you might want about the project.

 

[Marduke]

The last post in this thread was 6 months ago, and it seems like there has been a lot of advancement in the field since then. So what's out there right now?

:thinking:

Thread was started just a month and a half ago??

 

[JohnR66]

This thread is old, yes, but anyone wanting to procure LEDs for $$ commercial use should spend some money. Not even $50 for heaven's sake, buy a few namebrand emitters and try them out for your application.

 

[industry7]

:thinking:

Thread was started just a month and a half ago??

Ok, I had just finished reading the sticky where some the veteran members were explaining how they strongly dislike it when noobs start new threads, so I had spent like 45 minutes trying to find an old thread that was on topic. By the time I found this one I was so frustrated that my brain wasn't working correctly anymore and I thought this thread was perfect, when it's really not, and that the join date of the last person who posted was the post date. Ugh.

So I think my best bet at this point is just to start a new thread, since my posts here will not really be on topic.

 

[asdalton]

Cree keeps announcing new high efficiency white, the latest I think was something like 160lm/W. It seems like blue should be even better since you don't have losses in the phosphor, but I don't know what's actually available right now, as opposed to all the news making LEDs that are still a couple years from market.

No, blue is worse for lm/W.

The reason is that lumens, unlike other units like meters or kilograms, are weighted to human sense perception. The human eye is much more sensitive to yellow and green than to blue or red. When you add a phosphor to a blue emitter, the lm/W increases a lot--even though the photon efficiency goes down.

Colored LEDs are probably better specified by power efficiency or milliwatts emitted, rather than lumens.