Sanwu expander as compensator for bad spots from some Ball-lenses

[Light superglue]

Red Cowboy has mentioned many times that he could make a very far range burner from a single NUBM44 or 06 with G-2 by applying 3x Sanwu expander after 6x Cylindrical lenses for beam correction.

I wanted to check if G-2 was really necessary in this optic trail, because the possibility to shift lenses in Sanwu could compensate for a difference between what we call “bad Ball-lens” and “good Ball lens” preset in factory to produce a collimation almost equal to G-2.

In earlier thread I have found that at least half of Ball lenses on 06/08 make a thin linear spot on the wall like a well collimated G-2 would but what if we were unlucky enough to get one which spot is rectangular or square and fast diverging? Do we have to remove the Ball lens and replace it by G-2 with all add-ons like teflon tape/internal-external springs? Or maybe just use Sanwu especially in case of NUGM01 (or what else more powerful would appear in the future) which alone can still be more expensive than Sanwu is.

So I checked the spots from NUBM08 and NUGM01 purchased in the past from DTR both having “bad Ball lenses” on with and without Sanwu expander.
The setup parts are on pic.1 and 2. Current is 1A.
The Al M9x0.5 adapter is attached to an empty barrel for G-2 screwed directly into 12mm module with LD. NUBM08 Ball lenses are shorter than all other (05/06/07 and NUGMs) so allow more turns into Cu module but even with only 1.5 turns the setup was stable enough.

You can see that after Sanwu the 80x20mm spot from NUBM08 on the wall 5m away became a thin line 20x1.5mm (pic. 3-4) and the 30x20mm spot from NUGM01 became almost a dot 5x1.5mm (pic. 5-6) however with “wings”, so maybe a spatial filtering would be of some additional help here.

So my conclusion from these tests would be that with Sanwu we do not need to replace the “bad Ball lens” by G-2 in order to make a good pointer from any of these LDs and in case of square spot even cylindricals will be not necessary.

 

[dden4012]

Something is usually off to where the beam isn't coming out of the expander dead center. I believe it is from the small lens of the BE not being seated perfectly. Really no reason to pop the can off if your going to use a G2 and 3x BE.

 

[Light superglue]

Sorry, I did not understand what pic. are you referring to.
And how not to pop the can off if going to use G-2?

 

[dden4012]

Sorry no caffeine yet. What I mean is that the gball is going to provide a workable focus for use with the 3x BE so no sense in popping the can off to use a G2. I have a few builds with the NUGM01T, NUBM06, and NUBM07E that use the stock gball setup with a 3x BE. Works pretty good. Basically was posting to agree with your findings and elaborate some small issues I have with this approach. The part of my previous post about the beam not being perfectly centered coming out of the beam expander was to see if you have the same kind of issue and what you do to correct it or if you know the cause.

 

[RedCowboy]

Here's one that straight out of the GBall makes a pretty fat rectangle at 5 feet about 5m by 15mm and a bigger one at 15 feet about 10mm by 35mm, but with an emptied out 3 element lens barrel simply screwed into the little silver adaptor with the wide end facing the GBall and a few washers to keep it from crunching the GBall, this one has about 2 - 2.5 rotations of threads and that's plenty, it turns a big rectangle at 15-20 feet into a burner about as strong as a nubm44 with cylindrical correction, so get yourself a couple of sanwu 3X Beam expanders and experiment, they are great with these multi mode diodes.

Note that not all GBall lenses are set up the same, no they are set to the projector manufactures requirements, but a wide range will benefit and work well with the 3X BE, some are just too divergent and you may want to remove the can and accept the shorter working lifespan, but if at all possible keep the GBall intact and try a sanwu 3X BE, I love them and have never burnt one even when running 5W+ diodes for several minutes, they hold up well.

I just minutes ago made a couple very short videos to show the 3X BE in action with a NUBM06 that has it's GBall intact as it came. It works well and looks good.

 

[Alaskan]

...and the 30x20mm spot from NUGM01 became almost a dot 5x1.5mm (pic. 5-6).

The otherwise rectangle shape became a small spot? Is that because the beam is no longer set to infinity focus and instead a burning focus?

 

[Light superglue]

Hi Alaskan,

This is what I have expected to obtain - a burning spot. But if this spot would be made at long range (aka infinity) how should it be called if not "infinity focus"?

In general it makes me think that this (square spot emitting GBall + Sanwu) is the 2nd way to obtain collimated beams from MM diodes. The 1st was G-2 + cylindricals.

I think that post of RC above confirms it, too...

 

[Alaskan]

When I first heard about the gball diodes being a little out of focus I had thought we could just use an adjustable beam expander to fix that too. Nice that you can focus it down to a small burning spot too, if you want. Appreciate the clarification.

Chris

 

[Light superglue]

Another idea it made me think of would be passing 4 KEdged beams from NUBM44 through Sanwu expander before correcting/focusing with cylindricals (topic of my other thread). This could allow tighter convergence spot at 2-5m.

It cannot be done in the opposite way but even in such an optical trail a 60mm wide PCX would be needed at end. What may be too expensive...

 

[Lifetime17]

Hi,
I made a build with a 44 for a customer and he wants a BE adapter to fit the host for a JT BE Mini . So before i ship it i will test it out to see if there's a big difference. I also have builds with the G Ball to i can make an adapter for the BE.



Rich

 

[RedCowboy]

The otherwise rectangle shape became a small spot? Is that because the beam is no longer set to infinity focus and instead a burning focus?

No it's a rectangle and it diverges into a wider rectangle, the BE just shrinks it a bunch so that all that power is in a smaller area making it useful and prettier at night.

The GBall that has a decent profile, not perfect, but makes a half square can be used with the 3X BE pretty well, it has the benefit of being more efficient than a 3 element and having a longer focal length than a G2, so experiment and see, the distance can also effect performance, that is getting the BE as close as possible to the GBall.

But it is a rectangle.

EDIT: OK I looked at the question again, if all your using is a BE on a MM diode and it's making the spot round then you are likely clipping it's edges, but in your case you are running it out of a GBall, well GBalls can do some funny things, look at it at a longer distance, it will change again.

 

[dden4012]

No it's a rectangle and it diverges into a wider rectangle, the BE just shrinks it a bunch so that all that power is in a smaller area making it useful and prettier at night.

The GBall that has a decent profile, not perfect, but makes a half square can be used with the 3X BE pretty well, it has the benefit of being more efficient than a 3 element and having a longer focal length than a G2, so experiment and see, the distance can also effect performance, that is getting the BE as close as possible to the GBall.

But it is a rectangle.

EDIT: OK I looked at the question again, if all your using is a BE on a MM diode and it's making the spot round then you are likely clipping it's edges, but in your case you are running it out of a GBall, well GBalls can do some funny things, look at it at a longer distance, it will change again.

I have noticed that the orientation as shown in your photo swaps in the far field going from = to || and the adjustments made on the 3x BE only affects the distance or say width of the || , | | , | | ,but the height is inherent to the diode. I've had similar results with the 07E, 01T, and 06 gballs.

 

[RedCowboy]

Every single multi mode projector diode we use starts out wide but thin and ends up tall and skinny or vise versa, from the m-140 to the NUBM44 they all do that.

Just hold a NDB7875 in your hand focused to infinity and look at the beam as you rotate it, it has a wide and a narrow side and what you see in the air is the opposite.

This is why it's best to correct the aggressive axis to start with then use a Beam expander on the corrected beam, you get a lot better reach and keep the spot from becoming a very long line.

EDIT: Ok you say the height is inherent, it's not, that axis diverges also, just not as fast, compare a diode, say a NUBM44 with a 3 element and a NUBM44 with a 3 element and 3X BE both focused at 80 feet, you will see that the spot of the one with the 3X added is both shorter and narrower.

 

[dden4012]

Every single multi mode projector diode we use starts out wide but thin and ends up tall and skinny or vise versa, from the m-140 to the NUBM44 they all do that.

Just hold a NDB7875 in your hand focused to infinity and look at the beam as you rotate it, it has a wide and a narrow side and what you see in the air is the opposite.

This is why it's best to correct the aggressive axis to start with then use a Beam expander on the corrected beam, you get a lot better reach and keep the spot from becoming a very long line.

EDIT: Ok you say the height is inherent, it's not, that axis diverges also, just not as fast, compare a diode, say a NUBM44 with a 3 element and a NUBM44 with a 3 element and 3X BE both focused at 80 feet, you will see that the spot of the one with the 3X added is both shorter and narrower.

I see what you mean. I failed to express it clearly. Inherent was probably not the correct term. The point you made about the 3 element lens is interesting. There no getting around it. That one axis must be controlled additionally.
Talking about a g2 vs a good gball I would rather keep the gball intact. Even with a bad gball if your going to add a BE just keep it stock. Still going to get the said results in the far field. G2 is great for most SM but I don't like the results I get with these high power multimode. But even with a 3 element lens your going to get a line down range. So on topic of the op yeah keep the gball and add a beam expander. Plenty of canned diodes to use various lenses with.

 

[RedCowboy]

I really don't like the GBalls, I make use of some because I won them at auction for cheap, but a window diode is the way to go, that N-465 that DTR has looks like a nice one to correct, it should make a really nice beam with a 4X cyl pair, but that NUBM07 always has a fixed focus like a spotlight, and pulling the GBall kills them way early. That n-465 is a 4 watt diode, I suppose when the 7675's dry up we may see more builds with them, and the power of the 44 makes it worth correcting although they are fun with a 3 element and 3X BE, but with the 06 you take your chances, half of them focus too crummy to use.

It's not that the GBall is a bad lens, it's not a bad lens at all, but we can't adjust it's focus and pulling it is not a good option.