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

[kiyoukan]

interesting. i have heard of that mount but never seen one.
you say it wont be up the the task.
im going to call bull shit if you lock the diode down in the hole and move the lens vs a diode in a plate that moves you get the same effect.
the advantage of the moving lens vs diode plate is better themal transfer.
im still hoping someone will answer my question of brass vs aluminum. the only time i ever seem to find brass is in portable and limited mass electronics but for all large heatsinks its a mix of a copper core plus aluminum fins. now why is that we seem to be the only ones using brass?

[LaNeK779]

I say the standard LSP diode mount is not up to the task with shorter than 4mm FL lenses. I know, i have tried it. Others have, too.

i wish i had some pics to show you what i mean. it is not the lens that moves. it is the diode that moves. diode sits nicely in that small retaining plate and you can move it about by unloosening the 4 screws that hold it down

thermal transfer is not an easy discussion, especially the "how better or how worse" part. none of us is equiped to bring solid arguments to the table.

in terms of brass vs aluminium, alu is better for when there aren;t uniform changes in temperature. Stainless steel could also be considered under different circumstances. Here is an interesting read, then you can go on in google http://www.newport.com/Introduction-...3/content.aspx

[dave]

i'd like to note that the diode mount listed above works ok for collimators up to around 4mm
dave has another diode holder that allows for diode centering, which many people (and me)have tried with the 2.9 and 2.0mm FL lenses

I have been mulling this over, and keep coming back to the second design. Anything else will blow the size right up..

Chris, how did you find centering a diode in the second mount? OK, or a PITA?

[LaNeK779]

Well, i've only done it 4-5 times. The first time was a smallish PITA. But i improved quickly. Now it does not bother me at all.
I just loosen the bolts a bit (as little as possible) and then i use the allen wrench as a lever to move the plate around and tie it down

in general, i don't think we should overengineer as much as XY screw-adjustable diode mounts. dave's mount works.
Its only serious drawback is beam height. If it was to be made @19mm like the normal ones, we would be golden

is it just me, or was the 2.9 lens more difficult to center than the 2.0mm lens? Or did i get better in the meantime?

[dave]

I have just sent off a x between the original mount and the x/y adjustable mount, with a revised mounting plate, and a beam height of 19mm

[LaNeK779]

now that's what i call service

let's see how it turns out

[logsquared]

I'll chime in on a few points.

Brass Vs Aluminum. Its not so much the thermal transfer but the mechanical properties that make the biggest difference. Aluminum is like a marshmallow. For flat on flat its ok. Anything with high stress like a screw pushing against it or flexure in the metal brass is the clear winner.

Moving lens or moving diode? I think moving diode is the best solution. This should prove true especially for multiple diode combiners. To date I have built a lot of modules with these diodes. The biggest PITA is getting things overlapped or aligned with the high mag. telescopes. I believe that the moving lens is going to change the beam height or exit angle more than the moving diode. The lens is held at the same height at all times with the moving diode mount. So in theory after the diode is centered the beams should all be the same height and exit angle from one mount to the next. With the moving lens this will not be the case.

I certainly see the merits of the moving lens. However, I think it will cause more frustration in alignment than its worth.

my .02$

[CDBEAM]

LS...You're scrambling my brain !! If the Diode is mounted 19mm off the main optical plane...would that not also be a constant...the lens is centered to the optimal focus/least abberations. Having the property of adjustabillity will introduce some variables to the position of the beam relative to the optical bed...in either case ??? The final knife edging/combining alignment is done by adjustment to the knife edge mounts themselves. I must think on your post more !!!!

The real nut here...at least in my book... is the desireabillity of adjustment with a radial action ( Screw) for fine adjustment. Having a very slight loose pressure on a locking plate...and bumping things around...a little to the left...a little right...a little down....no...oops to far...back up again....well...it works....but...X-Y screw adjustment is better...in my book( Yes...slightly better....but more complicated for sure...requiring a bigger footprint ).

Now...as to WHAT to adjust...the LD or the lens....That is still an interesting question !!!...In your mount...you adjust the LD with screws...right ??? Perhaps...both methods are improvements...The discussion continues...and we learn as we go !! Thanks for everyones comments !!! BEAM

[logsquared]

A little offset gets amplified thru the telescope. Check my cheesy win paint.

[steve-o]

Yes, I've seen that, but would not moving the diode around have the same effect?