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optical models for the 'G' lenses

dbrown2k

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Does anyone have optical models or the relevant information to produce optical models for the standard aspherical 'G' lenses? I'm using the free WinLens3D basic software to rough out lens options.

I'm trying to find the lowest cost solution to get from 405nm laser (SLD3236VF) ~150mW down to a 100-200um spot diameter within 20mm or less of the diode emitter.

Thanks.
 



dbrown2k

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Thanks, i've sent a question to the folk at light machinery, will see what information they may be willing to share.

The best bet at the moment is looking like bi-convex / double convex lenses. Best prices i've found are ~$13 each, but because i need 24 of them i'm hoping that there may be an option in the $5 range per piece.

Looking at the drawings of the G-2 it appears to be non-symetrical bi-convex in shape so should be possible to bring the focus to a near point. (i've one ordered to experiment with)
 

dbrown2k

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lens diameter somewhere from 3mm up to 10mm which is set by the size of the module array of x6 to make an evenly spaced grid of 3 x 8
 

paul1598419

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Your best size would be 6.3mm in diameter. These will go into the 9mm lens housings we use for single element aspheric lenses.
 

steve001

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Does anyone have optical models or the relevant information to produce optical models for the standard aspherical 'G' lenses? I'm using the free WinLens3D basic software to rough out lens options.

I'm trying to find the lowest cost solution to get from 405nm laser (SLD3236VF) ~150mW down to a 100-200um spot diameter within 20mm or less of the diode emitter.

Thanks.
I don't think that's going to be achievable with short focal length off the shelf lenses.
 

Encap

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I don't think that's going to be achievable with short focal length off the shelf lenses.
Was my thinking as well and custom made special purpose lenses are going to be expensive for 24 of them.

You might want to rethink what you are doing so as to be able to use mass produced commercially available non-developmental lenses unless you have a lot of money to burn.
 

paul1598419

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If you are trying to get a 150 mW 405nm diode focused down to 100 um at a distance of 20mm and then do it for many diodes, why not use a more powerful 405nm diode and use less of them. As has been stated here already, it will take some custom optics to accomplish this at great cost. You could use the BDR-209 16X Blue Ray diode run at <500 mA to get 800 mW of optical power out, thus decreasing the number of diodes. Unless, this is not for one project and you need 24 separate projects here, this would be the best way to go about this. You will still need a custom lens, but not 24 of them.
 

dbrown2k

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Well the best i've found so far is Dia 6mm, 5mm focal length biconvex lens [https://www.aliexpress.com/item/Diameter-6MM-Focal-length-5-MM-UV-Fused-Silica-Lense-Double-Convex-Lens/32637495405.html]

Which seems to produce the required spot size using the slow axis 19deg. See attached ray plot, which is 133um diameter at the back face of the glass plate. Because i've not seen any drawings of how the aspherical lenses behave other than collimating, i'm not sure if they could be an option.

The issue with reducing the number of lasers (yes this is a single unit with 24) is the data rates become more onerous and getting the head moving and slowing down again, also becomes more problematic. The other issue is the BDR-209 16X as they seem to all be pulls and not available new or documented.
 

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paul1598419

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If I knew what you are trying to accomplish here, it would make my suggestions more pertinent. It seems you are using several lasers to plot something in 3D. Then again, it could be some sort of engraving device. IDK.
 

dbrown2k

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apologies, yes this is a printhead, planar 2d movement a fixed distance from a glass bed. With the lasers operating variable duration pulse widths to control the total energy per pulse.
 

Alaskan

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Have you run the numbers on a PCX lens? See what a 15 mm diameter 30 mm FL does, might be able to help, too bad no mounts to be found cheap, but lenses cheap. Unfortunately, likely to be far more expensive in the long run.
 
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logsquared

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Not sure what you app is but, a single G2 will be able to focus a SM 405 laser to a 100-200um spot no problem. If you need to get further from the emitter you could use a G2 (~4mm FL) to collimate and a second G2 downstream to focus. At the focal point you would have a very small spot <10um Im thinking.

Edit:

Lots of posts since I started typing this response.

The original G2 was lightpath model 357775. Google this model. All the lens equations are on lightpath's website
 
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dbrown2k

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That's the way i've been looking, but i don't have the data to work out /calculate spot diameters and distances using the G2 or similar aspherical lenses.

I dont think the planar convex is able to focus to a spot from the diverging output of the diode, but would work after collimation. Having a single element would simplify setup and reduce possible errors.
 




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