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

[steve-o]

Well, while we're waiting for logsquared's answer, I have another semi-offtopic question: to cool these we need peltiers. I've seen quite a few on ebay but don't know about the quality. Anybody know of a good quality but not too expensive source or name? I'm thinking about 1-2 inch square ones will do. And Wattage? 12V @ 3A is 36Watts.. sound about right?
.. and now back to the thread, already-in-progress (cue 'Jeapordy' music) ..

[polishedball]

Well, while we're waiting for logsquared's answer, I have another semi-offtopic question: to cool these we need peltiers. I've seen quite a few on ebay but don't know about the quality. Anybody know of a good quality but not too expensive source or name? I'm thinking about 1-2 inch square ones will do. And Wattage? 12V @ 3A is 36Watts.. sound about right?
.. and now back to the thread, already-in-progress (cue 'Jeapordy' music) ..

Any good means of using other than the sandwich method? I really don;t want to change beam height.

[logsquared]

i used some lenses I had around the shop. The FL's are 12 and 90mm.

[steve-o]

Any good means of using other than the sandwich method? I really don;t want to change beam height.

Possibly put the peltier between your LD housing and a heatsink (like a cpu heatsink) with a fan blowing (sucking) the heat away from the heatsink fins . It could not be recirculated within a sealed optics chamber though unless a reverse peltier was built inside to pull the heat out of the chamber and transfer it to the outside.

[steve-o]

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[steve-o]

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[CDBEAM]

Drlava...As you would anticipate....I am interested in one....or likely two of the sets of higher magnification C-lenses. If I am taking a flyer on one set....might as well go for two sets !!! Your point of a greater beam geometry at aperature is well taken....but.....the Red Quad I envision will eventually be for " Projector #2...and on THAT unit I will employ scanners which accept a 5mm beam....so....assuming that the combinationn of 6x on the C-lenses coupled with the short fL Colli lens will be the ticket....and that two (2) beams can be propagated into one (1) set of C-Lenses with good results.....yea....alot of assumptions going on here ....still....but...I am hopefull..time will tell !!

See attached latest design....which equalizes the beam path length by off setting the LD's

BEAM

[kiyoukan]

Hey were you able to get those pics?
Love that drawing.
I plan on doing that just with only 1 set.
i cant wait for my new lenses from thor and edmund to arrive.
my current lens im using gives me a crappy beam barely good enough for lumia.

[drlava]

Hi Andrew,

With the Optima lens (fl = 4mm, NA = 0.5, red coated) with no correction I got 8.57mrad.
With the cylinders I got 1.8mrad divergence with the 1st cylinder @ 3mm from the Collimator and 4mm x 1.5mm @ the 2nd cylinder aperture.
With the 1st cylinder @ 100mm from the collimator I got 0.8mrad and 4mmx4mm @ the 2nd cylinder aperture.

Ok, this is a start, but the slow axis must be EXTREMELY thin to be coming out at 1.5mm at the second aperture of correction, wow. Was the collimator focus adjusted at all between the two correction distances? It shouldn't be. All things being equal, I wouldn't expect such a large divergence change just by moving the correction pair further away from the collimator.

@ dr lava
with dave's 2.9mm fl lens , first lens at 64mm 4x4 beam 1.09mrad, no mystry beam wings after your lens

this makes sense. 2.9mm fl lens should give slightly worse divergence from the 4mm fl lens, and it appears that it does based on both of your numbers: 0.8 mrad vs 1.09 mrad after correction with the 405-g-2.

Test set up;

LSP (Dave) Short FL Collimation Lens @ 2.9 fL
Distance between Cylinderical lenses and Collimation Lens @ 60mm
LD @ ML520G71

Divergence without correction: 9.58 mrad

Near field expanded (corrected) slow axis width, cyls 60mm from collimator: 4.25 mm x 4.25mm

Far field corrected slow axis width 13.72 meters away @ 20mm x 10mm....or 1.14mrad

I am convinced the LSP Colli lens delivers better results than the 405 G 2

BEAM

thanks. again, this makes sense that the raw 2.9mm fl lens would give slightly worse divergence (9.58 mrad) than the raw 4mm fl lens: 8.57 mrad. Somehow I think these number have fewer accurate sig-digs

Anyway, I think there's enough info to order some up for testing for you, will keep in touch

[Solarfire]

Ok, this is a start, but the slow axis must be EXTREMELY thin to be coming out at 1.5mm at the second aperture of correction, wow. Was the collimator focus adjusted at all between the two correction distances? It shouldn't be. All things being equal, I wouldn't expect such a large divergence change just by moving the correction pair further away from the collimator.

The adjustment of the collimator was not changed for the 2 setups. I didn't think it would make such a big difference either when the cylinder correction is moved further from the collimator but Chris asked me to test this and it made a major difference. This also explains some discrepancies we have had in result comparisons due to people having placed the cylinders at different distances to the collimator. Chris also checked with an Optic manufacturer for assistance and they did some simulations and they also came up with an 8x telescope for the correction (was posted quit a few posts back).