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

**logsquared** · 10-01-2011, 07:12

Originally Posted by Solarfire

@logsquared
What’s the magnification on the cylinders you used?

5X. Because the beam is so divergent the magnification can be changed by adjusting the distance of the telescope from the diode. I don't have the Lava lenses but someone who does should try to put the first lens say 10-15 inches from the diode. Could increase the magnification, not sure?

**Solarfire** · 10-01-2011, 07:49

Originally Posted by CDBEAM

SF.. I used pseudonomen137's mRad Calculator ...plugging in 0 feet @ 5mm and 13 feet @ 8.25mm....and out pops .82 mRad... so...beats me ?? See pic

Is that 5mm @ 0 feet the beam width at the exit of the prism correction? If so then it's unlikley that the collimator is a 405-G-2 lens, because the beam geometry @ the cylinder exit should be about 1.5mm wide x 4-4.5mm high with a 4mm fl lens.

**Stoney3K** · 10-01-2011, 07:59

A 5mm beam with 0.82 mrad of divergence would mean we could have hit the jackpot here.

Sure, it may not be the perfect-TEM00 low divergence beam that DPSS and gas junkies would really like to see, but if we can get a beam like this with little effort and still have craploads of power to waste since the diodes are cheap and easy to overdrive, I guess nobody will complain, right?

**CDBEAM** · 10-01-2011, 08:04

Well....Yes....I did use 5mm....if you use 4mm....ya get 1.07mRad....Difficult to measure....but it does look closer to 4.- ~4.5mm just about 50mm past the front cylinderical lens....Yipe...I was dazzed by all those red photons from the " Fiesty Stipe" haha...Will pay more attention to detail. Thanx !!

Stoney....mRad about 1....not .82....sorry

CDBEAM

**kiyoukan** · 10-01-2011, 13:43

once you get this as best as you can i would love to come by and see it. maybe even bring my projector with 5mm mirrors over and see if it works.
Let me know!

**CDBEAM** · 10-01-2011, 20:12

Well....things did turn out better than I thought.....More luminosity...More power...Less cost...but more baloney with optics for each LD....And....can they be combined...at least into a dual ??? Likely they can. As to the task of properly placing the cylinderical lenses ( which are more demanding to set up than A Prisims)....I made a little drawing of what I am going to do.

Basically...a two piece clamping assembly. A machined, (3) three level, lower acrylic piece which nests the convex lens up front and a slot machined parallel with the beam axis for the concave lens in the back ( closest to the LD ). This back lens needs to be adjustable as there are likely variations between diodes. For my LD the optimal distance between lenses is 17.91 mm. This provides the lowest divergence/best beam geometry. The upper piece is just a acrylic slab...which is bolted to the lower piece via four (4) 6-32 allen head bolts. As with the A Prisms...I will take care as to NOT apply too much clamping force as to not crack the optics. I may use some very small rubber pcs to cushion the optics placed atop the lenses and upper slab...as I do with the A Prisms.

Just one way to secure these very small optics. This mount will then be secured to my LD platform.

Have fun !!

CDBEAM

**Fenechlaser** · 10-02-2011, 01:57

@ CD beam: What setup did you use for the best results you had as I got lost somewhere in the posts :/

Nice drawing, but do the optics fit tightly or is there some degree of freedom?

Thanks

**CDBEAM** · 10-02-2011, 06:20

FL...17.91 mm between lenses....for my diode... the top surface of both lenses are even in elevation...with the upper slab of acrylic clamping the optics and securing their positions. As to a friction fit vs a loose fit between the optics and the lower base....dunno ?? Surly very little friction ...if any, as this would make positioning more difficult than it is already going to be. Also, I may not machine a slot to position the convex front lens. The resulting fillet will not allow the lens flat facia to make full contact with the end of the slot. The fillet could be removed with a square file...or perhaps I will just machine a straight ledge...and glue/add a shoulder piece of bar stock plastic to provide side support and positioning to each side. Again...one way to secure these optics...simple and inexpensive.

CDBEAM

**flecom** · 10-02-2011, 12:39

4.5mm x 1.5mm is not bad at all... my 1W 655's are 5x5mm or 6x6mm cant remember... so you could take 3 of those diodes and knife edge them like ||| and still have a 4.5mm x 4.5mm beam!!!

**dave** · 10-02-2011, 20:32

Whats the consensus on safe output power for long diode life?

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A little mount for the Lava Cylinderical lenses

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