LED

[Dmx512]

Hi Techno people

anyone know what the brightest single L.E.D is on the market at the moment?

[Wol]

Luxeons are usually pretty bright! clicky

[chris ewington]

lamina lighting produce the brightest cluster led available. Each primary colour can be driven to 1.5 amps each.

 

www.I-pix.uk.com BB 4 uses these leds. The combined RGB source from lamina ships as a standard 60 degree beam. By adding optical accessories it is possible to concentrate the beam to 10 degrees of homogenized RGB light.

 

Lumileds K2 packs a punch but individually focuses each led source. This creates split shadows. Perfectly good, but there are now better ways of doing things that a company like lamina produce.

 

I hope this helps.

 

Chris.

[musht]

Define brightest?

 

Or there is various ways of answering it ;-)

 

Think brightest single dice LED is still Seoul Semi Conductors P4, which actually uses a dice from US Cree pacakeged by SSC.

 

Most efficient is also either Cree XLamp or SSC P4, on lumens per Watt, light out for power in, this is a constantly changing award sometimes week to week.

 

Lamina as Chris mentions along with people like Enfis, which think make bigger arrays than Lamina, and Taiwan`s Edison Opto produce multi dice arrays that are alot brighter than a single dice LED for a given surface area but due to thermal management issues are not as efficient l/W.

[chris ewington]

In my experience of working with lumileds leds and having put 18 RGB K2's up against the lamina led we use, the lamina led comes out brighter.

 

Actual power draw ( taking into account power supply inefficiencies ) compares as 42 watts for the 18 x K 2's and 30 watts for the Lamina light engine.

 

The novel optical arrangement for the lamina engine is different in its approach from the usual led and collimator solution.

 

The inefficiencies of the collimator solution = less performance.

 

Im working with a tight 10 degree optic now and I have found this concentration of beam to be pretty impressive by todays standards.

 

Lamina have completed the evolution in terms of optics and performance and right now it all seems a little too different for many fixture manufacturers caught in the trap of following each other.

 

You cant get away from the individual source problem the current solution of led and individual collimator provide. In a nutshell its a compromise in my opinion.

 

Blended RGB fixtures are now coming out and they look 10 times better than seeing the individual point sources.

 

In terms of calculations many manufacturers are quoting led efficeciences based on low junction temperatures, its simply unrealistic to see high lumen efficeinces when some manufacturers leds have differing and somewhat poorer ways of dissipating heat. Heat being the main compromise in design performance. Its common for many fixture designers to introduce limiting software linked to a thermister, which means as the led gets hotter, the drive notches back the heat build up. This is a compromise to keep the cost down.

 

The leds tessilated into fixtures create a collective heat management issue which should be addressed for real world use.

 

Then with heat you have to consider the countries away fromt he UK with overall higher ambient temperatures which adds to the fixtures running and performance.

 

With a fixture you are talking about a power supply with typically 10-20% innefficencies, coupled to the type of led and the heat dissipation of that led (remember performance drops from heat build up, both in short term and long term degradation of the led. Also there are inefficiencies in the electronics behind driving the leds. Then the optical path has 10-30% inefficiences, so when you consider the entire system even if a led works well at 25 degrees, that not how it will be used.

 

Considering every aspect of the 'system' then we will see how certain manufacturers of leds will behave as they give actual real world performance.

 

 

 

Its an interesting area of development now and I expect as the point source gets progrssivly brighter the heat management will become an even bigger issue.

 

There are interesting developments on the horizon with oled development with some manufacturers now quoting 5000 hour lifetimes, but thats still pretty low.

 

Needless to say the humble incadescent source is long overdue for replacement in driving down power consumption so we can all do a little bit in taking our industry away from being very power hungry.

 

 

Ive seen a lot of LD's this year and every one of them has said how bored they are at seeing leds as individual point sources.

 

So we are back to the problem of not only what the source does, but how it looks.

 

Enfis's solution has the same optical problems lamina started with in 2004 when I first saw their wide angle array.

 

Im hoping Enfis will do well being a british company and I wish them well, but they do need to solve the problem of concentrating the beam sufficiently to be capable of using.

 

Im sure they will.

 

Back to the current collimator optics out there. Im not sure they are as efficient as the manufacturers quote. In the past ive heard of 80% + efficiency but having seeing the lamina engine and optic against this fixture im surprised.

 

We have some interesting developments in the pipeline which will help prove how bright the leds are by comparison.

 

I hope this helps.

 

Chris

[musht]

Thanks for the comprehensive reply, good to see manufacturers talk realistically about how that magical 140l/W* never actually makes it out the fitting. Power supply efficiency, neg temp coefficient and optical losses.

 

Interesting point on more homogenised sources, which intially wouldn`t have thought affects white sources as much, but may do with a vogue for colour temp tuneable means cramming some amber in there and getting it to mix.

 

*140 Lumens per Watt quoted by a big LED maker for their new white LED, but as Chris explained,

thats watts supplied at the LEDs own preferred voltage, so power supply loses power some regulating it,

Tj 25 C, junction temperature right in the heart of the LED not at the heatsink at the back, unobtainable in real life apart from first few milliseconds of switching it on.

Even top purity glass is only 95% transmissive, optical acrylics used for lenses is a bit less.