Dimmable LED/flash microscope illuminator

[Saul]

Saul,

Another excellent combination of LED and Flash. As we've shown on another thread an LED, or LED COB simply can't compete with the Xeon flash tube in terms of short high energy optical bursts helpful for "freezing" vibration effects.

1ms seems about the limit for practical LED use, but you've solved that by using both the LED for modeling and Spedlight for Flash, which can easily produce 100us bursts!...

Thanks, Mike !

Now can we entice you to make one of these LED Speedlight combos for macro use outside the microscope

Will try, will try , ha ha, not sure regarding the result ...

[mawyatt]

Saul,

Another excellent combination of LED and Flash. As we've shown on another thread an LED, or LED COB simply can't compete with the Xeon flash tube in terms of short high energy optical bursts helpful for "freezing" vibration effects.

1ms seems about the limit for practical LED use, but you've solved that by using both the LED for modeling and Spedlight for Flash, which can easily produce 100us bursts!...

Thanks, Mike !

Now can we entice you to make one of these LED Speedlight combos for macro use outside the microscope

Will try, will try , ha ha, not sure regarding the result ...

If you do decide I've got the electronics for LED done, custom PCBs being fabricated and parts on order. This does include using the LED as a strobe, as well as modeling light, but result will be much weaker than a flash tube for strobe. I can save one for you if you want.

BTW the nice, cheap IKEA Jansjo lamps work really well with a higher power and 5000K LED COB. I modified all 4 including the one that the clamp broke, 3 have ~1000lumen LED COBs and 1 has the 2400 lumen LED COB.

https://www.photomacrography.net/forum/ ... hp?t=41464

Best,

[Saul]

One more model (in parallel to the existing one) - more powerful, swap-able heatsink (let's say you want UV version also), can be used for non flash version, etc.

Even more, the same heatsink can be used for both LEDs - reversed to the another side.






Even more, the same heatsink can be used for both LEDs - reversed to the another side. Parts are kept together by strong neodymium magnets and centered by the hex screws (non-detachable version - heatsink is mounted permanently).
r


LED power is set to the approx 20w (could be even more by attaching extra heatsinks to the extrusion (which works very well as a heatsink)). Photo, of course , is just for fun, but extra heatsinks are not a problem ...



Using optical glass light guide instead open path allowed me to use more powerful LED and create higher, more concentrated light output.



Unit is powered from the separate power supply



It could be used with the different faceplates, same as the previous model

[Saul]

More photos

[Smokedaddy]

Very creative Saul. Nice work as always.

-JW:

[Perl]

Hi

Any Version that work With Leitz Orthoplan and Ortholux II ?

Best Regards
Pär

[enricosavazzi]

[...]
I would like to see some comments and samples about how to get Kolher illumination, the advantages of the models with fly eye lens...and so
[...]

I would like too, but so far have found nothing definitive. http://www.microscopy-uk.org.uk/mag/art ... ohler.html seems to imply that the fly-eye lens is made necessary to obtain a uniformly illuminated field that is otherwise not possible with a LED, but does not really explain why. Other sites say instead that digital cameras are very sensitive to uneven field illumination and that the fly-eye lens is better than traditional optics in providing the required uniform field illumination. Yet other sites briefly talk of fly-eye microscope illuminators without even mentioning Köhler illumination.

The Nikon Eclipse 100 microscope brochure at https://d33b8x22mym97j.cloudfront.net/p ... focal=none mentions that this microscope uses a LED illuminator with fly-eye lens (swappable with a halogen illuminator, unclear if also this with fly-eye lens) that provides a "simplified Kohler's illumination system". So is this a true Köhler made easier to align, or just a "best effort" Köhler approximation good enough for students?

The Nikon patent https://patentimages.storage.googleapis ... 507434.pdf says that the fly-eye lens illuminates uniformly a broader subject area than traditional optics. It makes no mention of Köhler.

One thing that several sources mention is that two sheets of fly-eye lenses should be used, with the second lens sheet at the focus of the first sheet and vice versa. This supposedly makes the borders between adjacent lenslets strongly out of focus in the subject plane and thus not visible in the image.

[Saul]

...Any Version that work With Leitz Orthoplan and Ortholux II ?...

Hi Pär,
Not yet (do not have access to these microscopes).
If you're really interested, please PM me

[Saul]

[...]
I would like to see some comments and samples about how to get Kolher illumination, the advantages of the models with fly eye lens...and so
[...]

I would like too, but so far have found nothing definitive. http://www.microscopy-uk.org.uk/mag/art ... ohler.html seems to imply that the fly-eye lens is made necessary to obtain a uniformly illuminated field that is otherwise not possible with a LED, but does not really explain why. Other sites say instead that digital cameras are very sensitive to uneven field illumination and that the fly-eye lens is better than traditional optics in providing the required uniform field illumination. Yet other sites briefly talk of fly-eye microscope illuminators without even mentioning Köhler illumination.

The Nikon Eclipse 100 microscope brochure at https://d33b8x22mym97j.cloudfront.net/p ... focal=none mentions that this microscope uses a LED illuminator with fly-eye lens (swappable with a halogen illuminator, unclear if also this with fly-eye lens) that provides a "simplified Kohler's illumination system". So is this a true Köhler made easier to align, or just a "best effort" Köhler approximation good enough for students?

The Nikon patent https://patentimages.storage.googleapis ... 507434.pdf says that the fly-eye lens illuminates uniformly a broader subject area than traditional optics. It makes no mention of Köhler.

One thing that several sources mention is that two sheets of fly-eye lenses should be used, with the second lens sheet at the focus of the first sheet and vice versa. This supposedly makes the borders between adjacent lenslets strongly out of focus in the subject plane and thus not visible in the image.

Thanks, Enrico, for the useful links. And your link from the your previous post, great information.

Another thing is that this white paper makes an example with a double lenslet sheet for better uniformity, but in the Nikon illuminator there
seems to be only one (there is an example of this arrangement earlier in the paper).

I suspect (just suspect) - it is right combination of the internal optic. Today I made some tests with the illuminator (simplified version, just LED, no flash option, will post later about it) on the Nikon vertical illuminator with Optiphot - got "nice" focused grid of "ommatidias" , have to adjust distances or make some focusing system.
On the Microphot (using big 20w COB led) - it was almost great, only at the smallest illuminator's aperture's opening I started seeing spots of the separate LEDs.

Regarding Köhler - to make universal illumminator with Köhler, I think, (in my case/design) it is almost impossible . Agree with JohnyM
https://www.photomacrography.net/forum/ ... 39#p244639

Of course, if I'll find something suitable for the double fly-eye system - will try for sure

[Saul]

Finalized version with heatsink which can handle approx. 22w (continuous duty). This design allows to use more powerful LEDs also (there is no heat stress on the 3D printed body) with bigger heatsink (or adding additional surfaces to the existing one (big plus of the T-Slot extrusion)). That all allows to use different LEDs, depending on the user's needs .

COB emitting surface diameter should be 12-15mm, to match light guide dimensions.
Was able to squeeze electronics inside, so no external voltage upconverter is needed, just simple power supply.

Photos show Optiphot 2/ Microphot FXA version, but other faceplates are available (same like on the lower power versions)
First photo shows optional power connector for DIY set if needed (standard set has everything inside)

[Saul]

LED version only, but can be upgraded to the direct flash plus LED version also. Picture shows simple heatsink, but unit can be used with much more powerful LEDs using bigger heatsinks.