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

[CDBEAM]

The question of beam power vs. quality vs. cost must be taken in context with what your projector is required to do and what you can afford. Five (5) variables…therefore 5! Factorial. If my math is correct that means there are 120 ways to combine these variables….and a huge range within each variable. Point is that this question is a huge, complicated mess !!!

PL is just a microcosm of the real world. So as with so many issues, there are a huge number of solutions and each solution is the right one….at that particular point in time, based on the variables for that person. From the Renke projector up to Kvant, Arctos, X-laser, Connecticut Lasers and Gas rigs… from mono to six channel color…from DIY 200mW to Professional 20 Watt systems( And beyond).

Then, for more confusion…let’s throw in unit reliability, Professional vs. Neighborhood “Ooo Aaaa” show and ease of projector transport.
There are a huge number of solution to choose from….and they all depend on the individual.

Would I choose 2 or 3 watts of 635nm at 0.85 mrad, with a nearfield of 3mm for my RGB ??? All costing under 1K ??? You bet !!!! But….for now the technology has not caught up with my dreams !!! So….the G71 is a compromise !!! As is the 445LD….another compromise.

If I had MUCH greater funds…I would not settle for these compromises….but….for now…for CDBEAM and my needs….the G71 has been brought under sufficient optical control to fit my needs and expectations. If my needs or means increase…..then I may change my expectations. For now….I am as happy as a Pig in …. !!

Each of us has their unique perspective on this question. Pay yer money and take yer pick !! There is one thing you can know for sure !!! Within a year….we will have other choices in LD’s !!! We are approaching the “ knee” of information/technology/\...Hang on to your hat and enjoy the ride !!! BEAM

[steve-o]

All good points, Beam. I'm confused, tho (which is nothing new) by these last few posts.. I thought professional laser show companies use pro (aka; very expensive) equipment, and hobbiests on a budget build our own and invent things (like we did on this thread.)
Yeah, the beams are not perfect, but the power density is now fairly acceptable, and although not perfect, when scanning, the average Joe in the audience can't really tell the difference, can he? Personally I'm not thrilled by the 445 color, it's a little too dim and violet for my tastes but add a punch of 532 in there and it comes real close to the appearance of an argon 488 as far as my eyeballs can see.
If I were a pro lasershow company I'd probably have several 20W+ whitelight watercooled 3 phase mixed-gas units and a lot of arctos, kvant etc satellites just for grins. But being the neighborhood once-in-a-while show guy I'm happy with having a 2+Watt projector that I can carry with one hand under my arm .
As far as 660 vs 638 goes, I've worked with both and no contest, the locs, despite their superior beam quality, are just too dim.

[LaNeK779]

well, if i can just put some glass in front of some diodes and with some tweaking and frustration i get this, i think i can proclaim it a success
next thing is to get it scanning the dr lava standard cyls and 2mm dave lens combination works for me

dot is approx 1x2cm at 10meters and the greenie is just a standard low cost greenie
those wings are a pain in the back side though. it think there is some power in there, that will have to get clipped

[andythemechanic]

Looks, like abberations from the cylindrical lens pair. Almost impossible to clip away. I would try to adjust them better.

And the 660nm in my projector is mainly to get good mix colors. Violet for example with 445nm and 637nm looks just pale. the ~0.8W of 660nm can hardly compete with 300mW of 642nm in brightness, but they improve color appearance dramatically. Ideally there would be 405nm and 473nm in the projector as well for even nicer colors but that's another story.

Andreas

[Fenechlaser]

those wings are a pain in the back side though. it think there is some power in there, that will have to get clipped

Put your setup in a projector and check the beam profile again. My blue has a 'wing' on one side which is barely visible after passing the beam through the galvo mirrors.

Also, I don't know if this has been asked, but does the mits 71 turn led just below threshold like the 445s? I did not manage to find it anywhere..

[LaNeK779]

Put your setup in a projector and check the beam profile again. My blue has a 'wing' on one side which is barely visible after passing the beam through the galvo mirrors.

Also, I don't know if this has been asked, but does the mits 71 turn led just below threshold like the 445s? I did not manage to find it anywhere..

hey mister fenech

yes, these diodes have a slight glow when under lasing threshold, but it depends on the diode driver you use. with a flexmod you will see it, with the others that have standby beam suppresion, you will not. i am not really worried about the wings, i know that once scanned it will go away.

Looks, like abberations from the cylindrical lens pair. Almost impossible to clip away. I would try to adjust them better.

thanks for the answer andreas. i am not really stating this as a problem. it most probably comes from my choice of collimator, the particular lens is known to have some excess "noise". these wings go away if i use different FL collimators, even with the same cyl pair

again, i was not refering to the wings as a problem, i just got greedy and wanted the last mw out of these. nothing serious, carry on please!

[Solarfire]

Looks, like abberations from the cylindrical lens pair. Almost impossible to clip away. I would try to adjust them better.

And the 660nm in my projector is mainly to get good mix colors. Violet for example with 445nm and 637nm looks just pale. the ~0.8W of 660nm can hardly compete with 300mW of 642nm in brightness, but they improve color appearance dramatically. Ideally there would be 405nm and 473nm in the projector as well for even nicer colors but that's another story.

Andreas

I'm also planning some 660nm in my projectors for the same reason. What are you using to combine the 660nm and the 642nm?

[andythemechanic]

I'm also planning some 660nm in my projectors for the same reason. What are you using to combine the 660nm and the 642nm?

Just a standard polcube and a half wave plate. I always build even a dual with knife edging to have the polarisation DOF for wavelength combining. I have build two new 340mW 637nm setups this way just some weeks ago:



Combining with a custom dichroic would be possible, but hard to align and very expensive because of the small wavelngth difference.

[CDBEAM]

The following lyrics are for the 1962 Bobby Pickett song..." The Monster Mash " ...See http://www.themonstermash.com/mmdex.html
Albiet not technical...appropreate none the less !! ENJOY !!! BEAM

I was working in the lab late one night
When my eyes beheld an eerie sight
For my Laser from the slab began to rise
And suddenly to my surprise

It did the flash
It did the G71 photon flash
The photon flash
It was a coherent smash
It did the flash
It zipped by my eyelash
It did the flash
It did the photon flash

From my laboratory in the castle east
To the master bedroom, last but not least
The joules all came from their humble abodes
To get a jolt from my 5VDC electrodes

We did the flash
We did the G71 photon flash
The photon flash
It was a coherent smash
We did the flash
It zipped by my eyelash
We did the flash
We did the photon flash

The light beams danced, we were all having fun
The party had just begun
The guests included the whole PL Clan
Red, Green and Blue was the game plan

The scene was rockin', we were all were digging the beams
The scanners were humming, sometimes a few screams
The Light-Bangers were about to arrive
With their vocal group, "The Photon-Kicker Five"

They did the flash
They did the G71 photon flash
The photon flash
It was a coherent smash
They did the flash
It zipped by many a eyelash
They did the flash
The did the photon flash

Out from crowd, a voice did ring
Seems there was trouble about just one thing
Someone spoke up and shook his fist
And said, "Whatever happened to my LOC twist?"

It's now the “ Flash “
It's now the G71 photon flash
The photon flash
And it's a coherent smash
It's now the “ Flash “
The G71 Photon flash

Now everything's cool, on the 635 nano band
And the G71 Flash is the hit of the land
For you, the living, this Flash was meant too
When you get to my door, tell’em…Terrawatt sent you

Then you can Flash
Then you can G71 photon Flash
The photon flash
And do the coherent smash
Then you can flash
It will zip by your eyelash
Then you can flash
Then you can photon flash

[LaNeK779]

hey andreas, i have to ask. where can one get that little right angle prism thingy you use to knife-edge?


nice song mister beam