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Laser Diode holder for larger than 6.33mm Coli Lens

CDBEAM777

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As promised,

Some thoughts on using 12.75mm or 20mm Coli lens .....To be labeled as CBALM ( Chris's Big Ass Lens Mount )

1) Such a mount ...of course can be done.
2) It will be a limited demand/ market so low numbers would be sold.
3) Low units made = Higher production cost....
4) Can we use ANY existing components to lower the cost ?
5) Problem is that there are many, many different host geometries to couple up to ...What to do ?? !!

OK....for now....I propose....the Mount becomes a host for the Lens only....and a standard 12 x 30 LD holder be coupled to this Lens holder....so....the standard M9 x 0.5 Metric Fine Thread would apply. A plain M9 x 0.5 section would couple the Standard 12 x 30 LD holder to the Lens Mount ( CBALM).

Do we want the to incorporate Cylindrical Lenses ???? Then...Radial adjustment demands will change the coupling approach !! I would then go with a 12mm bore socket and three (3) Set screw use to secure the 12 x 30 LD OD....into the CBALM 12mm socket !! This is demanded because we MUST have the ability to set the rotation angle of the LD relative to the C-Lenses.

SO....assuming that C-Lenses will also be used down beam of the Coli lens.....the standard shelf arrangement would be employed. I am designing...in my head as I type this…..so....details are NOT yet filled in....such as How to secure / lock in the Coli Lens ??? May require a two (2) piece capture method ????? Just as the flat glass window of a torch is captured / locked into place with a Bezel ring ???

Anyway....No drawings yet.....will cartoon within a week...… Hope Chris like the name ???? HAHAHAHAHA
CDBEAM
 



Alaskan

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CBALM, hmmm.... I guess that's OK. Are you thinking of using the existing lens mounts with a flared output end to accept a larger lens? If we are going to use cylinder lenses to correct the beam shape, as is desired for the higher power laser diodes with their bar shaped outputs, better to accomplish that before the final big ass collimation lens so we don't need to use huge cylinder lenses.

If so, we then need to make this as an add on to a smaller 6 mm collimation lens. That would be better than we have now, but the extra collimation lens (the 6 mm lens) isn't a good thing due to the extra induced loss with one more lens in the assembly.

Adding even more glass, if correcting the beam shape with cylinder pairs, we would then need to add another lens after them to expand the beam again to use a larger collimation lens on the output to make that fat beam for lower divergence, that makes two extra lenses, in addition to the cylinder pairs for a total of four extra lenses. I'd be happy to have a far more simple assembly with just one big ass lens to collimate the raw output from the diode and forget correcting the beam shape.
 
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steve001

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CBALM, hmmm.... I guess that's OK. Are you thinking of using the existing lens mounts with a flared output end to accept a larger lens? If we are going to use cylinder lenses to correct the beam shape, as is desired for the higher power laser diodes with their bar shaped outputs, better to accomplish that before the final big ass collimation lens so we don't need to use huge cylinder lenses.

If so, we then need to make this as an add on to a smaller 6 mm collimation lens. That would be better than we have now, but the extra collimation lens (the 6 mm lens) isn't a good thing due to the extra induced loss with one more lens in the assembly.

Adding even more glass, if correcting the beam shape with cylinder pairs, we would then need to add another lens after them to expand the beam again to use a larger collimation lens on the output to make that fat beam for lower divergence, that makes two extra lenses, in addition to the cylinder pairs for a total of four extra lenses. I'd be happy to have a far more simple assembly with just one big ass lens to collimate the raw output from the diode and forget correcting the beam shape.
Optics are available with <_ 0.4% loss per surface. Example: https://www.edmundoptics.com/p/127mm-x-127mm-x-50mm-fl-vis-0deg-beam-shaping-fused-silica-cylinder-lens/37134/
Edmund also has pcx and pretty sure aspherics sporting the same.
The lose for a 4 lens optical assembly is at most 1.6% of the raw diodes output
 
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Alaskan

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You mean .4 percent per optic. With quality AR coated optics which have that low of a loss, nothing wrong with that. I'm happy with up to 5% to 7% total loss as an acceptable amount, so that's more than good to me.
 

DTR

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I am working on organizing my next production run of modules and I had been wanting do a small batch of the 25mm or 20mm mounts maybe both with a larger threading to accommodate larger diameter lenses. Some lenses out of a group funded projectors way back I did with Lazeerer and Daguin who posted some very interesting test results on. I have a lot that I have been collecting over the years but never actually got around to working out a mounting solution for. See here.




My thinking before reading this thread was M11X0.5mm. New brass lens barrel with an outer threading of M11X0.5mm and inner threading of M9X0.5mm. Could use old lenses as legacy support and maybe even use an empty one as the retaining ring instead of having to make some right off that bat. That would support diameters maybe up to 10.5mm but am open to suggestions.

I will be adding about 0.5mm to the length of all the diode mounts specifically from the lip/stop for the pressed in diode to the top of the module giving a little more threading for the longer focal length lenses.

Only concern there I have which any input would be appreciate before I commit to the change which will work with the DTR-G-2 using the focus rings I use but due to the large variations of barrel and optic sold as G-2 out there might be some that will have issues. Like I have seen some a while back that had a thicker lip the lens sits on moving it up in the barrels a tad higher or could be some other variations out there where the barrel is slightness shorter, focus rings size or threaded or threaded slightly deeper. And most of all actual variations optic geometry that might need to be closer to the diode to fully collimate.



Another change is to the 25mm driver shelf backs enlarged so that they can fit the full BB8 just needs to be a little wider. Was not possible on the 20mm without going to a half moon cut of the hole back half and when deciding to do a 25mm variation I only had them change the diameter keeping all other specs including the size of the driver pocket without thinking about it and kicked my self for a while for not. Another good reason to get input to changes..


Here is a the post on the lens with the testing Angelos did from that thread linked above.

Lazeerer;257023 said:
I Just did a couple Power readings and Measurements of this lens that Came out of the "Pan" Projector.:)

Here are some Photos and Videos of my results.:)

The Power Test Videos:

I Compared this "Pan" Lens to a G2 lens in both these videos.

Here is a Power Reading using a Mitsu 500mW P73 638nm diode:



Here is the Power Reading using a 9mm 445nm diode(For some reason it wont let me Post more then 1 video at a time so here is the link):



There seems to be a Slight power difference between The "Pan" Lens and the G2 lens. I have not yet dont a Cut out module setup to see if this power difference is due to a Clipped beam or some other factor. But I believe its not being Clipped. The Focal length seems to be somewhere ~7mm. Ill get you guys the exact number when i make the cut out module this weekend.:)


Here are also some Pictures I took at 22 feet of the Dot Comparison. Sorry its a little difficult to see the numbers on the 445nm shots. It was very difficult to show it without washing out the camera picture.

First up is the 500mW Mitsu 638nm P73 diode with the "Pan" Lens:
(22 Feet Distance/ 38.69mm Dot "-" Size)


Dropped My Calipers during theses Pictures.:( Cracked the Glass on the display.Errr

Now with the G2 lens:
(22 Feet Distance/ 66.95mm Dot "-" Size)



Here are the Picture with the 9mm 445nm diode.

First up is the 9mm 445nm diode with the "Pan" Lens:
(22 Feet Distance/ 17.15mm Dot "-" Size)


With G2 lens Now:
(22 Feet Distance/ 28.41mm Dot "-" Size)



Here is a Picture how i mounted the lens. Basically i Machined the Lens nut out on the inside IIRC 7.6mm which allowed a perfect lip for the Crown of the lens to sit on. I used a Little Thermal Adhesive to hold the lens in place and then centered it and let it set for 12 hours. It mounted perfectly. The Module i used where the longer copper modules that DTR has and the lens fits in there perfect.:) With the Stander size Modules the problem is not the Diameter of the lens as that will fit, but the problem is the depth due to the way i mounted it the module has to be longer since the threads dont start till the lens is already past focus. Iam not sure if its possible to machine a lens nut for this lens to fit in a stander size 12mm module.


Here are a couple photos of the lens coating and shape:

Front:


Back:


Thanks.:)
 

reloader45

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Mar 17, 2019
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Hello,

I am very interested in this bigger lenses. Where can I buy this bigger lenses, especially the 12,75 mm lens?


best regards

Edgar
 




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