Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[logsquared]

Sounds right, my test was with the O-Like blue coat. Do you know the FL of the red coat?

FL = 8mm, or very close. divergence is 4.3mRad.

[polishedball]

That means with a lens like the Optima (4mm FL, >97% transmittion) you will get approximatly 540mW at the same power. Get the picture?

That lens provided me terrible results post 407, it clipped and mis-shaped the beam.

[polishedball]

@polishedball: what current is that at? I haven't taken mine over .5A. Very tempted though.

I'll measure no idea, the diodes I have a few so wasn't concerned esp after reading the torture test they endure over on lpf. I am pretty sure that I have crossed the 1amp mark though when flatline testing (increase of amps gave no more output then decrease).

I stuck a power meter on it, increased the amp until it flat lined about mid 600's then just brought it down to 400mw for some testing with the other lasers.

If I am loosing 38% to the Lens then when my 2.6mm FL reds get here I should see near a watt out of this diode.

[logsquared]

I'll measure no idea, the diodes I have a few so wasn't concerned esp after reading the torture test they endure over on lpf.

Do you have a link to the torture testing. Some threads over there have thousands of posts.

[CDBEAM]

Somewhere....way back in the first few pages of this thread....Mixedgas made reference to some built in overload protection feature of the ML520G71....that you could overdive it....for awhile.....and that it would show no signs of degredation.....but then it would fail. Maybe SOME amount of overdrive has little or no impact ???? Unknown at this time !!

Mixedgas did work on this diode over a year ago ( I seem to remember ) This overload feature may remain on the current ML520G71??? or not ???...so...therein is our dilema.....how far...if at all.... to overdrive ???? I guess it really depends on your personal application !!!! If you are depending on a projector to do profesional shows.....and have a mass crowd to please....that is one case !!! And it is a case in which projector reliabillity is of utmost importance !!! If you are just putting on a show for friends and have no obligation to perform....that is entirely a different story !!!! PL is comprised of both...."One size does not fit all !!!" Surly....many of us are of a more relaxed projector application !! THEN....it is a matter of cost/operating hours. That ratio is highly impacted by the number of multiple diodes in a given array !!! The ratio will further be effected by amount of over current employed. OR....I could be full of it....and the current ML520G71 is as bullet proof as the multi-emitter 445LD ????

SO many unknowns !!!!!!! I wish I had complete knowledge of MTTF with a given percentage of over-drive for the ML520G71 !!!...or....we could arrive at an optical beam correction which is acceptable for the ML520G71....and apply that correction to the ML501P73.....and be on the convervative side....and drive to 500mW per diode. MANY options !!...MANY variables !!

A grand balancing between: mW output, nm, divergence, beam geometry at aperature, overall beam geometry quality, # of LD's necessary per array, diode life, diode cost, % of overdrive, beam correction method/cost and complication to set up, Collimation lens choice and cost....and likely other variables I have forgotton. No wonder this thread is soooo long !!

BEAM

[steve-o]

Originally written by CDBeam:
Mixedgas did work on this diode over a year ago ( I seem to remember ) This overload feature may remain on the current ML520G71

I believe what Steve (Mixed-gas) was referring to
was not so much overload protection, but over-rating (derating) the component to fullfill the MTTF (life expetancy) of the component; factory specification. Agreed, they will fail prematurely, no question about it. Can we get 1/2 life from it? 1/4 .. ? We may not know until later (at the worst possible time)- there is a law about electronic component failures similar to Murphy's law. I can't remember it right now but it states that a component will fail at the least desirable condition e.g. high power SCR will fail in the shorted (closed) condition rather than open .

[badger1666]

got my first dual up and running
from cold bangs out over 800mw at 500ma.
at 580ma and show it a little tec cooling you see the right side of 1w.
whoop whoop

[CDBEAM]

Yikes...." ICE IS NICE " comes to mind !!! A LITTLE overdrive....a little TEC....2 to 3 FL on the Collimations lenses and some Cylinderical lenses......and 2W at the 637 line !! Mmmmmmmmmmm !!! Goooooood !! Cookie !!!

BEAM

[steve-o]

'Gratz Badger!!!!! Pix Pleez !!

.. wait , 800mw from 500 ma ?? Somehow the math isnt adding up . 500ma each right?

Be sure to leave it running for a solid 48 hours to make sure that it doesn't crap-out

[Stoney3K]

also made a nice yellow with 350mw of green, this red at 380mw.

Attachment 28609Attachment 28610

So a 1:1 ratio with about twice as much blue would come near a proper balanced white?

Sounds like a good start for my RGB build, 250mW of 532, a single ML520G71 and a 1W 445. No nonsense, simple build, but good brightness for beam shows.