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

[LaNeK779]

well andy, there is not much to ponder
if this special lens is identified and working, we are talking about 1 watt of 635 with super beam specs for less than 400 usd
then we can apply this special lens to the blue diode too and get it to have super beam specs, too

if this is the case, we are GOLDEN

[andyf97]

well andy, there is not much to ponder

if this special lens is identified and working, we are talking about 1 watt of 635 with super beam specs for less than 400 usd

then we can apply this special lens to the blue diode too and get it to have super beam specs, too

Duno if it will work on the blue, I will try it.

And its 638nm not 635nm more red than orange.

[EDIT]

I cant see tho how it could ever be done with more diodes tho, been pondering this all morning.

Any ideas?

[CDBEAM]

Andy,

I am currently using the 405 G 2 collimination lens.

As far as the orientation of the first optic...PVC....well....I tried the other way....with very bad results.....??? I am no Optics Guru....that is for sure !!

I have been searching the web for the last few hours...trying to find examples of C-Lens arrangments....with little luck !!!

I have no idea if I am wrong ??????

Possibly...such close placement to the collimination lens is necessary...I will try that

Other PL members...PLEASE comment !!!

Thanx !

CDBEAM

[CDBEAM]

AND....a comment on LaNeK779 suggestion of using an optics programme !! That might be a much faster way to run various configurations !!! How much does such a programme cost...NOT cheap I bet !!! I will just add that to my wish list !!!
CDBEAM

[andyf97]

Andy,

I am currently using the 405 G 2 collimination lens.

As far as the orientation of the first optic....well....I tried the other way....with very bad results.....??? I am no Optics Guru....that is for sure !!

I have been searching the web for the last few hours...trying to find examples of C-Lens arrangments....with little luck !!!

I have no idea if I am wrong ??????

Possibly...such close placement to the collimination lens is necessary...I will try that

Other PL members...PLEASE comment !!!

Thanx !

CDBEAM

with a 405G2 you'll get some beam of a kind but not so great and it will also be quite fat..

[steve-o]

Yikes !!!!!!!!!!
[/[ATTACH=CONFIG]28085ATTACH]

LOL, CD! Always liked that actor. He's great!

Steve, if you want to use prisms you will have a fat beam, if your happy with a fat beam use two not just one and then you will have a rounder fat beam. There are posts some place in the forum for placing prisms and am sure somebody could drop into this thread one sketch of how to place them.

Yes I know the placement of an anamorphic prism pair. I prefer using 1 prism, it's the same size square beam out either way, just a steeper angle. Why is 1 prism wrong?
I will definitely try Dr Lavas cylinder lenses if they provide better beam profile than prisms. Are there plans for an 635 AR coated DrLava lens set?

[steve-o]

Well, did some measurements, and overdriving at 618mA got 5x5mm at the output of the prism , 10x47mm at 100 feet (1.38 mRad divergence according to Pseudonomen's divergence calculator), 230 mW @ 1" after the prism with my el-cheap-o setup with an aixiz lens. So I believe there's hope. I wouldn't rely on these for the main reds in a projector (they could fail at anytime being over-driven like this) but as an add-on for extra power.. nice . .
Still hoping too for the 'special lens' to be found and available :] Any luck identifying it Andy?

[taggalucci]

Taggalucci, i have a simple question for your points.

Before I respond to this, I want you to understand that all of my commentary has no ill intent. I am just as keen as you and the others here to find diodes that make powerful and useable red (638nm to 640nm), less costly than it otherwise is. So when I query and challenge, this is not an attack - all good science requires evidence. So when I seek out that evidence, it's not a challenge of your skill, intellect, penis-size etc. It is because I genuinely want real results for us all. I hope you understand and can handle this without taking it the wrong way.

So if you don't agree with my points etc, I'm cool with that. And in your disagreement, I'm encouraging you to provide the evidence that you'll be able to if these diodes truly are ideal for replacing the expensive multi-diode array reds.

I would like it if you did find the evidence for us all. That would be great!

If you take 8 opnext diodes and knife edge them together into a 4x4 grid & I take 2 Mitsu diodes and combine them together into a single 4mmx4mm beam using a pbs and correction with the same divergence as the opnext combined beams, which has the most power density within 5mm x 5mm space at 10 meters.

There are quite a few assumptions in this:

1) Both diodes can be PBS cubed. So for power density comparisons, either PBS both or not at all.
2) I don't believe we've seen your power readings for the ML...G71 with a 4mm x 4mm beam at aperture with equivalent divergence to the Opnexts producing the same beam profile.

I'm no optics expert so am more than happy to be corrected on this... My understanding is that shorter FLs which would get you the ideal starting beam size (especially for knife edging) would result in higher divergences to be tamed by the cylindrical lenses (the magnification factors of which become increasingly challenging). I also believe that it's easier from a stability and far-field alignment perspective to knife-edge fatter beams and telescope down than to knife-edge small and telescope up. All of the mechanics and optics to do this become increasingly expensive and so I believe one gets diminishing returns from these diodes.

And finally, this is where my thinking is in terms of power density...

The Mitsubishi ML520G71 diodes at spec can produce ~300mW on an 2µm x 40µm sized emitter. The Opnext HL63133DG can produce ~170mW on a 2µm x 3µm emitter. So according to my maths (which could be flawed and happy to be corrected)... At spec, the power density at the emitter's edge would theoretically be ~375 MegaWatt / cm² for the Mitsi's vs. ~2,833 MegaWatt / cm² for the Opnexts. More than 7.5x the density (no wonder these buggers are sensitive).

Assuming the accepted overdriven values of the ML520G71 at ~500mW and the HL63133DG at ~200mW, ~625 MW / cm² for the Mitsi's vs. ~3,333 MW / cm² for the Opnexts. More than 5x the density.

So if you agree with my thinking and maths on this then you can understand why I am sceptical to believe it cheaper to use the Mitsi's to get equivalent power densities within equivalent beam specs.

It is likely, based on others experience that it would be possible to get 12 (2x3 array x 2 via PBS) of the Opnexts into a <4mm diameter beam @ ~1 mRad doing ~2W after optics. The optics and mechanics to do this is reasonably straight forward and can be bought easily with little custom machining: diode mounts, collimator lenses, knife-edge mounts, mirrors, PBS, PBS mount, telescope, telescope mounts.

I would assume you'd need at least 5 of the ML520G71 to achieve 2W after optics. I'm not sure the physics will allow the combining of 5 of these to produce a <4mm diameter beam @ ~1 mRad, never mind being able to do so for less cost.

You have to get use to the idea this new diode is going to have similar implications as the blue did.

I hope so Andy, just hanging out for the evidence.

[Edited in] Don't take my word for it, do your own tests like I did.

I'm happy to, especially if there's evidence this is worth doing. Until then, my limited resources at present will be focussed on solutions with known results.

Please keep up your efforts, we all want you to succeed.

[mixedgas]

Like Tag, I have my doubts.

Has anyone tested this "Pseudonomen's divergence calculator" against a Spiricon or Knife Edge test?

Steve

[steve-o]

It's gotten very quiet again ... maybe too quiet .. ...