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DIY Scienscope fiberoptic light
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Saul



Joined: 31 Jan 2011
Posts: 914
Location: Naperville, IL USA

PostPosted: Wed Sep 21, 2016 8:55 am    Post subject: Reply with quote

Chris S. wrote:
...I’d be interested in seeing more details of your reflector/collimator approach...

Pau wrote:
Me too!


Quick drawing of the existing one




...and link to the 3D view of the adapter:
https://www.3dvieweronline.com/members/Id1baff70e2669e8376347efd3a874a341/v5SafNHMGnH48iW
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Saul
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Pau
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Joined: 20 Jan 2010
Posts: 4008
Location: Valencia, Spain

PostPosted: Wed Sep 21, 2016 9:26 am    Post subject: Reply with quote

Thanks for the illustrations!

Now what for me are the key questions:
- Is the light more collimated and/or more intense that if you just place the FO at the same distance of the LED without the Lens + snoot adapter?

- Is the light more intense that if you just place the FO just as close as possible to the LED?

I affirmative to both questions, what kind of lens do you use?
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Saul



Joined: 31 Jan 2011
Posts: 914
Location: Naperville, IL USA

PostPosted: Wed Sep 21, 2016 9:55 am    Post subject: Reply with quote

Chris S. wrote:

In my experience, EKE bulbs cast plenty of light for 100x, even with cross-polarization, which wastes most of the light. Without X-pol, I have to dial back the intensity using my illuminators’ irises, in order to permit the 8-second exposures I prefer. Also, this is often with a quad head, which of course divides the light four ways. If you’re willing to use exposures in the realm of two seconds, I think you’ll be fine. This said, my experience may only apply if you can concentrate and collimate the light into the FO light guide with a parabolic reflector, or perhaps another approach.

BTW, I’m not at all sure that the light need be concentrated within the physical diameter of the FO light guide. I had a conversation about this with a leading researcher in fiber optics. He described optical fibers as having a numerical aperture/entrance cone. His sense was that my collimated light source need only fall within the optical fiber’s entrance cone—which would be larger than the diameter of the FO light guide—to be transmitted down the light guide.


Chris, thanks for the information !
Maybe I'm looking too much ? At 20x I had to keep guides ~1cm from the paper diffuser and little bit less than 1cm from diffuser to the specimen, 3s exposure.
Sellers stating that 30w LED is ~2000 lm. I do not want to go more than 5s exposure - I have to rewrite my PLC program for longer exposure , it has some limitations.
I cannot use EKE reflector - this LED is too big.

Pau wrote:
Now what for me are the key questions:
- Is the light more collimated and/or more intense that if you just place the FO at the same distance of the LED without the Lens + snoot adapter?

Hard to tell. I have to find the right way to measure it. I have Minolta flashmeter, maybe it will work ?

Quote:
- Is the light more intense that if you just place the FO just as close as possible to the LED?

I do not think so. And, what is most interesting, I tried this approach with 5w LED also, both 5w and 30w looked very similar. I suspect, because of the FO angle of acceptance, same count of subLED's fits to this cone angle.

Maybe I have to try Cree LED, I have couple
http://i.ebayimg.com/images/g/2HkAAOSwDk5T40dr/s-l1600.jpg
Problem is that they are not continuous duty - heatsink is too small, heats up within few minutes. I have hardware ready to position them close to the FO entrance.

Quote:
I affirmative to both questions, what kind of lens do you use?

http://www.ebay.com/itm/2pc44mm-Lens-Reflector-Collimator-Fixed-bracket-For-20W-30W-50W-70W-100W-LED-/261497551804?hash=item3ce277fbbc:g:v1gAAOxyzi9Si6s1
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Saul
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Saul



Joined: 31 Jan 2011
Posts: 914
Location: Naperville, IL USA

PostPosted: Fri Sep 23, 2016 7:04 pm    Post subject: Reply with quote

Saul wrote:
Pau wrote:
- Is the light more intense that if you just place the FO just as close as possible to the LED?


I do not think so. And, what is most interesting, I tried this approach with 5w LED also, both 5w and 30w looked very similar. I suspect, because of the FO angle of acceptance, same count of subLED's fits to this cone angle.


Pau,
Made couple more tests - you are right, LED should be as close as possible !
So now I have two options - try condenser with big surface LED (30w or 100w), if it will not work - use 10w LED (which I used in the test and pretty happy with results, http://i.ebayimg.com/images/g/ZE0AAOSwGtRXxJEt/s-l1600.jpg), or CREE XHP70 (which is coming)
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Saul
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Saul



Joined: 31 Jan 2011
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Location: Naperville, IL USA

PostPosted: Mon Sep 26, 2016 7:21 pm    Post subject: Reply with quote

Some test setup photos

With

Car type 4w LED light bulb


AO condenser 30w LED


Just 10w LED, as close as possible to the FO entrance


30w LED with the condenser worked better than with the cone adapter. Best results are with 10w LED (last picture). I hope with the Cree XHP70, which has greater lm output, results will be even better
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Saul
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Saul



Joined: 31 Jan 2011
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Location: Naperville, IL USA

PostPosted: Wed Oct 05, 2016 9:33 pm    Post subject: Reply with quote

Just to finalize - results with the Cree XHP70 LED are great
Discover card offer - to cover fan's air stream. Just in case ... Wink
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jcb



Joined: 11 Jun 2011
Posts: 40
Location: France

PostPosted: Fri Oct 07, 2016 12:57 am    Post subject: Reply with quote

Very interesting as I am trying to understand those LEDs and the electronics that drive them. Could you list the equipment you use from the mains plug to the Cree LED ? What is the Cree LED color temperature ?
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Saul



Joined: 31 Jan 2011
Posts: 914
Location: Naperville, IL USA

PostPosted: Fri Oct 07, 2016 12:03 pm    Post subject: Reply with quote

jcb wrote:
Could you list the equipment you use from the mains plug to the Cree LED ? What is the Cree LED color temperature ?

Hi JCB,
I'm using very simple stuff - just 12v power supply and PWM dimmer.


Cree XHP70 LED color temperature - white ( not warm white or blue white)

BR,
Saul
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vitikin



Joined: 04 Dec 2012
Posts: 9

PostPosted: Sat Oct 08, 2016 8:07 pm    Post subject: Reply with quote

I built a FO illuminator with a 100W LED source.
My experience:
Heat IS AN ISSUE!!
I tried several options to get the light into the entrance pupil of the FO conductor. I tried directly shoning the LED into the FO guide. I tried to diffuse the light with a spherical diffuser, and I tried diffusing the light and keeping it inside the diffuser. NONE of the options gave me a strong enough light at the other end of the FO guide. In fact, the light out was kind of underwhelming.
Pictures following:

Then I modified the jig to accept a EKE light...120V 250W...and heat was MORE of the same. it melted my 12V adaptor for the fans!. However the light at the other end of the FO guide was very strong.
I wonder if I use a less powerful EKE lamp, say a 100W 12V bulb, what results would I get.

That's my next project







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vitikin



Joined: 04 Dec 2012
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PostPosted: Sat Oct 08, 2016 8:13 pm    Post subject: Reply with quote

This is the same jig, modified for EKE lights:


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Chris S.
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Joined: 05 Apr 2009
Posts: 2850
Location: Ohio, USA

PostPosted: Sat Oct 08, 2016 9:07 pm    Post subject: Reply with quote

Vitikin,

Interesting project! And your null results will save others from trying the same things.

What say you go back to your LED, but use either a parabolic reflector (as an EKE bulb does) or lenses to parallelize its light output and size it to the entrance cone of the fiber optic light guide? This, I think, is the magic behind why an EKE bulb produces much more light at the FO light guide's output.

Cheers,

--Chris S.
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Pau
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Joined: 20 Jan 2010
Posts: 4008
Location: Valencia, Spain

PostPosted: Sun Oct 09, 2016 12:36 am    Post subject: Reply with quote

Quote:
I tried several options to get the light into the entrance pupil of the FO conductor. I tried directly shoning the LED into the FO guide. I tried to diffuse the light with a spherical diffuser, and I tried diffusing the light and keeping it inside the diffuser. NONE of the options gave me a strong enough light at the other end of the FO guide.

In my short experience the only approach that will work with a big light source like your COB LED is by means of lenses, but you would need to design the adequate optics. Did you see my links at my first post?

Quote:
I wonder if I use a less powerful EKE lamp, say a 100W 12V bulb, what results would I get.

That's my next project


Nice project. I admire your DIY skills but...you can buy complete and working used FO illuminators for very good prices
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Saul



Joined: 31 Jan 2011
Posts: 914
Location: Naperville, IL USA

PostPosted: Sun Oct 09, 2016 9:28 pm    Post subject: Reply with quote

Pau wrote:
Did you see my links at my first post?

Hi vitikin,
My advice, please read these Pau's links... And links inside these links... Smile
Now I have some extra big surface 30w & 100w LEDs and drivers . I bought them first and Pau posted links later - more DIY parts for some my future projects Smile
You'll find great ideas in these links. This forum is amazing because of these beautiful bright friendly people united by macro idea ...
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vitikin



Joined: 04 Dec 2012
Posts: 9

PostPosted: Wed Oct 12, 2016 11:31 am    Post subject: Reply with quote

"Nice project. I admire your DIY skills but...you can buy complete and working used FO illuminators for very good prices "

Absolutely. But, where is the fun in that?!
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Pau
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Joined: 20 Jan 2010
Posts: 4008
Location: Valencia, Spain

PostPosted: Sun Dec 04, 2016 1:24 pm    Post subject: Reply with quote

Saul, take a look at the the device I've found at ebay:
http://www.ebay.com/itm/Led-light-source-replacement-for-zeiss-opmi-pico-microscope-/322349286924?hash=item4b0d83c60c:g:rV0AAOSw44BYRGCu

It does just the same I proposed and you're doing: putting an adequately sized powerful LED close to the FO entrance Very Happy
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