Interesting optics thread

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Agro
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Interesting optics thread

There are many optics that are interesting for some reason but neither fit any existing topic nor are worth having their own one.
Let’s discuss them here….

Agro
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Knight Optical has a family of extremely strong Fresnel lenses, F# = 0.2.
15 mm lens needs to be just 3 mm above the die to focus on it.

This leads to very high light collection – 82% of all light gets captured to the beam.

They are available in many sizes from 15 mm to 125 mm.

High collection is close to high efficiency but is not all of it. The lenses are not AR coated stock (but manufacturer offers such option). They’ll suffer pretty high reflections at the peripherials unless coated.

Will they throw?

1. Fresnels suffer from reflections off the peaks, that reduces throw
2. Strong lenses are worse collimators than weaker ones
3. Fresnels have larger clear aperture than regular lenses of the same diameter – giving them natural 23% throw advantage over a standard aspheric
4. These are “precision” grade items

So….I have no idea if they throw but I wouldn’t expect them to have record-breaking potential.

But they have other advantages:

  • super short zooming movement makes head design easier
  • little effort to adjust focus
  • head can be very compact
  • the lenses are very lightweight

So…interesing base for a small, light and efficient zoomie. Smile

ADDED: NTKJ has a similar line, from 15 to 250 mm:
https://www.ntkj-japan.com/fresnel-lens/
At 50+ mm they offer even higher pitch. And they have negative lenses of the same strength as well (but only 25, 50, 100mm).

LouieAtienza
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They make TIR lenses for things like emergency lighting that puts out a square beam aand they have them with different beam angles as well. Don’t know what it’s called but I know Polymer Optics in UK is one company that makes them.

Speaking of interesting optics they have a few, from hybrid TIR/reflectors, 3-up color-mixing lenses, some crazy Fresnel lenses for IR detection…

LouieAtienza
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Agro wrote:

Knight Optical has a family of extremely strong Fresnel lenses, F# = 0.2.
15 mm lens needs to be just 3 mm above the die to focus on it.

This leads to very high light collection – 82% of all light gets captured to the beam.

They are available in many sizes from 15 mm to 125 mm.

High collection is close to high efficiency but is not all of it. The lenses are not AR coated stock (but manufacturer offers such option). They’ll suffer pretty high reflections at the peripherials unless coated.

Will they throw?

1. Fresnels suffer from reflections off the peaks, that reduces throw
2. Strong lenses are worse collimators than weaker ones
3. Fresnels have larger clear aperture than regular lenses of the same diameter – giving them natural 23% throw advantage over a standard aspheric
4. These are “precision” grade items

So….I have no idea if they throw but I wouldn’t expect them to have record-breaking potential.

But they have other advantages:

  • super short zooming movement makes head design easier
  • little effort to adjust focus
  • head can be very compact
  • the lenses are very lightweight

So…interesing base for a small, light and efficient zoomie. Smile

ADDED: NTKJ has a similar line, from 15 to 250 mm:
https://www.ntkj-japan.com/fresnel-lens/
At 50+ mm they offer even higher pitch. And they have negative lenses of the same strength as well (but only 25, 50, 100mm).

I built a version of Enderman’s Light Cannon with a Fresnel (thread in the Spotlight section). Similar to Light Cannon and OptoFire, the light source moves – in effect creating a zoomie. It’s actually pretty cool going from pencil beam to column of light 4” in diameter. I might print GOBOs to flash onto walls like the moving head beam projectors. I’ve even considered making cheap moving head projectors with Fresnel lenses, the light weight would need just small NEMA14 steppers…

Terry Oregon
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Interesting that this conversation came up.  I have this Acrylite diffusion lens arriving today (52mm), which will fit my Maglite.

https://www.flashlightlens.com/index.php?app=ecom&ns=prodshow&ref=acrylite_lens

Heard about it on another forum, just wanted to see how well it works.

 

My reviews: , My personal collection of lights LINK,  J5 Tactical V1 Pro review LINK,  Thirteen Optical Sensors review LINKZebralight SC700d review LINK,  Ray-O-Vac Super Power Sportsman review LINK,  Convoy S2+ color combos LINK,  How To flash D4V2 LINK.

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Thanks for starting this thread. The LEDiL Seanna doesn’t fit anywhere well. Even fewer people have tried them. And they aren’t particularly practical. Not even sure who they made these for. I tried with and then without the inner lens (12ft) to see the difference in this Osram white flat 1mm^2 build. Without the inner lens it might have more cd but produces some strange colors. The last picture is with only the inner lens and no Fresnel. The ring is about 12 feet across and around 8 feet away.





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Inkidu wrote:
Thanks for starting this thread. The LEDiL Seanna doesn’t fit anywhere well. Even fewer people have tried them. And they aren’t particularly practical. Not even sure who they made these for. I tried with and then without the inner lens (12ft) to see the difference in this Osram white flat 1mm^2 build. Without the inner lens it might have more cd but produces some strange colors. The last picture is with only the inner lens and no Fresnel. The ring is about 12 feet across and around 8 feet away.

I thought about this too. Methinks the TIR is made to collect the LED light from the outer beam angles, with the Fresnel taking care of the front of the beam? I’m not sure if the Seanna was even intended for LEDs like a White Flat, and I did notice those rings in the fully assembled light. But when I held the MCPCB against the installation “plane” I didn’t recall seeing those rings, at least that pronounced, so I think perhaps the White Flat is not in the optimal position vertically?

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LouieAtienza wrote:
I thought about this too. Methinks the TIR is made to collect the LED light from the outer beam angles, with the Fresnel taking care of the front of the beam? I’m not sure if the Seanna was even intended for LEDs like a White Flat, and I did notice those rings in the fully assembled light. But when I held the MCPCB against the installation “plane” I didn’t recall seeing those rings, at least that pronounced, so I think perhaps the White Flat is not in the optimal position vertically?

Thanks for the reply. I tend to agree with you. The similar Black Flat is in their documentation. I reached out to Ledil about MCPCB and they sent me some info. Some of which I posted in this thread. Not much use for me, but its nice to see they would try to help. I like to play around with some different gaskets but there is not much out there yet for this LED. I wish I had way to calculate cd/lm to know if I’m close. That efficiency number is quite high.
Page 4 of the spec sheet.
LED OSLON Black Flat
FWHM 1.2°
Efficiency 94 %
Peak intensity 1196.000 cd/lm
LEDs/each optic 1
Light colour White
Firelight2
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Interesting optics.

I’m not sure a 15mm fresnel lens with 3mm focal length would be that useful though.

I experimented with fresnel zoomies a few years ago. I had a combination of cheap fresnel lenses (about $8 each) and more expensive ones (around $30 each). My impressions:

  • A short focal length doesn’t increase throw at all …. all it does is give you a wider hotspot. to increase throw you need a wider or better quality lens.
  • The default cheap plastic aspheric lens that comes with an $8 zoomie easily outthrew both fresnel lenses by a significant margin.
  • Both fresnel lenses were able to produce wider flood beams than with the stock aspheric lens
  • Due to light scatter off the peaks of the fresnel lens the area outside of the beam tended to be softly lit, compared to pitch dark with the aspheric lens.
  • The cheap fresnel lens (I forget where I got it) had a longer focal length and didn’t throw as well as the more expensive one from Edmund Optics. The cheap one produced a fuzzy square in spot mode. The more expensive one produced an actual image of the die… not as sharp as with the stock aspheric lens however.

So based on my experience this is what I would expect of the 15mm fresnel with 3mm focal length:

  • Very wide hotspot (image of the LED surface)… almost as wide as the beam in full flood mode.
  • Flood mode would probably be relatively narrow. The problem is the focal length is just too short. For practical purposes you need to leave at least a 1mm gap between the back of the lens and the top of the emitter dome… that’s already 1/3 of the focal length used up. Then there is the height of the dome itself. Even for an XPL HI or Black Flat with a flat dome that’s probably another 1 mm.
  • Throw (intensity of the brightest point in the hotspot in throw mode), would be worse than a cheap 15mm aspheric lens that costs less than $1.
  • Overall this lens probably wouldn’t make for a very good zoomie, with its narrow flood, minimal distinction between the spot and flood beam, and inferior throw.
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Agro wrote:

Knight Optical has a family of extremely strong Fresnel lenses, F# = 0.2.
15 mm lens needs to be just 3 mm above the die to focus on it.

This leads to very high light collection – 82% of all light gets captured to the beam.

They are available in many sizes from 15 mm to 125 mm.

High collection is close to high efficiency but is not all of it. The lenses are not AR coated stock (but manufacturer offers such option). They’ll suffer pretty high reflections at the peripherials unless coated.

Will they throw?

1. Fresnels suffer from reflections off the peaks, that reduces throw
2. Strong lenses are worse collimators than weaker ones
3. Fresnels have larger clear aperture than regular lenses of the same diameter – giving them natural 23% throw advantage over a standard aspheric
4. These are “precision” grade items

So….I have no idea if they throw but I wouldn’t expect them to have record-breaking potential.

But they have other advantages:

  • super short zooming movement makes head design easier
  • little effort to adjust focus
  • head can be very compact
  • the lenses are very lightweight

So…interesing base for a small, light and efficient zoomie. Smile

ADDED: NTKJ has a similar line, from 15 to 250 mm:
https://www.ntkj-japan.com/fresnel-lens/
At 50+ mm they offer even higher pitch. And they have negative lenses of the same strength as well (but only 25, 50, 100mm).

I think if you were building an ultra-short-throw video projector on the cheap, these could work great!

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LouieAtienza wrote:

I think if you were building an ultra-short-throw video projector on the cheap, these could work great!

Those would work horrible, as the fresnel ridges would completely distort any image projected through it.
Projectors require precision grade single surface glass lenses.
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Enderman wrote:
LouieAtienza wrote:
I think if you were building an ultra-short-throw video projector on the cheap, these could work great!
Those would work horrible, as the fresnel ridges would completely distort any image projected through it. Projectors require precision grade single surface glass lenses.

Yes, for 720p I agree. For cheapie 480p LCD projector, it probably doesn’t matter. The final lens yes should be glass but in back of the LCD can be Fresnel (to collimate the light from the LED), and in fact with the cheap Amazon projectors the lens in front of the LCD is also Fresnel.

Sure I can go to Edmund or ThorFire and get some precision ground lenses… but this is Budget Light Forum, not “the sky’s the limit budget” LOLOL! I emphasize “on the cheap” here. Sure it’s cheaper to just buy a crap DLP projector off eBay and put a brighter LED, but that’s not a build – that’s an installation job. That’s no fun.

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Just thought I’d put up this oldie but goodie optic for nostagia sake, from Inova TIROS series. It had a really great narrow throw with just a little spill.

Regrettably I had to send my light in for repair for a cracked bezel lens and rather than replace the lens they replaced my entire light but with a newer reflector based model Sad Had I known they would not return my light I would have simply replaced the cracked lens myself. I miss that beam.

Seeking the light.

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LouieAtienza wrote:

Yes, for 720p I agree. For cheapie 480p LCD projector, it probably doesn’t matter. The final lens yes should be glass but in back of the LCD can be Fresnel (to collimate the light from the LED), and in fact with the cheap Amazon projectors the lens in front of the LCD is also Fresnel.

Sure I can go to Edmund or ThorFire and get some precision ground lenses… but this is Budget Light Forum, not “the sky’s the limit budget” LOLOL! I emphasize “on the cheap” here. Sure it’s cheaper to just buy a crap DLP projector off eBay and put a brighter LED, but that’s not a build – that’s an installation job. That’s no fun.


First of all, projectors do not collimate light.
Otherwise the image would be a few centimeters in size.
The entire point of a projector is to do the opposite, and project a large image not a small one.

Second, even 480p would be completely distorted.
No matter what resolution you use it would be completely messed up not only due to chromatic aberration but also because the ridges of a fresnel lens are not perfectly aspherical.

Imagine your projector has a resolution of 1 pixel, it would still look like crap.
You can see this by looking at the die image of fresnel throwers, it doesn’t even look like a square anymore.

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Firelight2 wrote:
Interesting optics.

I’m not sure a 15mm fresnel lens with 3mm focal length would be that useful though.

I experimented with fresnel zoomies a few years ago. I had a combination of cheap fresnel lenses (about $8 each) and more expensive ones (around $30 each). My impressions:

  • A short focal length doesn’t increase throw at all …. all it does is give you a wider hotspot. to increase throw you need a wider or better quality lens.
  • The default cheap plastic aspheric lens that comes with an $8 zoomie easily outthrew both fresnel lenses by a significant margin.
  • Both fresnel lenses were able to produce wider flood beams than with the stock aspheric lens
  • Due to light scatter off the peaks of the fresnel lens the area outside of the beam tended to be softly lit, compared to pitch dark with the aspheric lens.
  • The cheap fresnel lens (I forget where I got it) had a longer focal length and didn’t throw as well as the more expensive one from Edmund Optics. The cheap one produced a fuzzy square in spot mode. The more expensive one produced an actual image of the die… not as sharp as with the stock aspheric lens however.

So based on my experience this is what I would expect of the 15mm fresnel with 3mm focal length:

  • Very wide hotspot (image of the LED surface)… almost as wide as the beam in full flood mode.
  • Flood mode would probably be relatively narrow. The problem is the focal length is just too short. For practical purposes you need to leave at least a 1mm gap between the back of the lens and the top of the emitter dome… that’s already 1/3 of the focal length used up. Then there is the height of the dome itself. Even for an XPL HI or Black Flat with a flat dome that’s probably another 1 mm.
  • Throw (intensity of the brightest point in the hotspot in throw mode), would be worse than a cheap 15mm aspheric lens that costs less than $1.
  • Overall this lens probably wouldn’t make for a very good zoomie, with its narrow flood, minimal distinction between the spot and flood beam, and inferior throw.

Thanks a lot for sharing your thoughts and experiences!

Some of this could be improved, f.e.:

  • these lenses have smaller groves than Edmunds which hints at higher quality – but that’s not warranted
  • using a lens much larger than 15 mm makes any necessary gaps less significant
  • using a LED that has extremely thin silicone layer may do the same (White Flat?)

So I really don’t think that in a well done light the flood would have width close to throw.

Also now I noticed that such light could put more lumens in the beam than any optics other than TIR.

But seeing your results I’m really not convinced it’s worth trying.

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pc_light wrote:
Just thought I’d put up this oldie but goodie optic for nostagia sake, from Inova TIROS series. It had a really great narrow throw with just a little spill.

Regrettably I had to send my light in for repair for a cracked bezel lens and rather than replace the lens they replaced my entire light but with a newer reflector based model Sad Had I known they would not return my light I would have simply replaced the cracked lens myself. I miss that beam.


Interesting…is it glass? What’s the size?
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This is from Can Fang’s (4sevens) very recommendable synopsis: LED optics in flashlights

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Enderman wrote:
LouieAtienza wrote:

Yes, for 720p I agree. For cheapie 480p LCD projector, it probably doesn’t matter. The final lens yes should be glass but in back of the LCD can be Fresnel (to collimate the light from the LED), and in fact with the cheap Amazon projectors the lens in front of the LCD is also Fresnel.

Sure I can go to Edmund or ThorFire and get some precision ground lenses… but this is Budget Light Forum, not “the sky’s the limit budget” LOLOL! I emphasize “on the cheap” here. Sure it’s cheaper to just buy a crap DLP projector off eBay and put a brighter LED, but that’s not a build – that’s an installation job. That’s no fun.


First of all, projectors do not collimate light.
Otherwise the image would be a few centimeters in size.
The entire point of a projector is to do the opposite, and project a large image not a small one.

Second, even 480p would be completely distorted.
No matter what resolution you use it would be completely messed up not only due to chromatic aberration but also because the ridges of a fresnel lens are not perfectly aspherical.

Imagine your projector has a resolution of 1 pixel, it would still look like crap.
You can see this by looking at the die image of fresnel throwers, it doesn’t even look like a square anymore.

Because the LCD screen will only allow light to pass through perpendicular to its plane the light has to be collimated to allow this. AFTER the light has left the LCD it is then focused on the projecting lens. You can argue about distortion all you want and are 100% right. But they’ve been making cheap projectors like this now for at least a decade. They’ve been using Fresnels in overhead projectors for decades.

As to Fresnel throwers… You can see in my pics I project an almost perfectly square die image – 200 yards into a brick wall. It’s rectangular now because I put a 2mm^2 in. I can’t capture it with my cell phone but at 40ft focused i could read the inscription on the MCPCB at 40ft. Possibly because the RLT moved on me and is illuminating the whole MCPCB.

So sure, I don’t expect a hi-def video projection. But you can search the thousands of YouTube videos of both DIY and cheap manufactued video projectors and see the image quality, while not great, is far better than you describe.

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Agro wrote:
Interesting…is it glass? What’s the size?
If I recall correctly, it was made of Polycarbonate. The diameter of the optic from that light was about 1-inch at the widest point.

Seeking the light.

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LouieAtienza wrote:

Because the LCD screen will only allow light to pass through perpendicular to its plane the light has to be collimated to allow this. AFTER the light has left the LCD it is then focused on the projecting lens. You can argue about distortion all you want and are 100% right. But they’ve been making cheap projectors like this now for at least a decade. They’ve been using Fresnels in overhead projectors for decades.

As to Fresnel throwers… You can see in my pics I project an almost perfectly square die image – 200 yards into a brick wall. It’s rectangular now because I put a 2mm^2 in. I can’t capture it with my cell phone but at 40ft focused i could read the inscription on the MCPCB at 40ft. Possibly because the RLT moved on me and is illuminating the whole MCPCB.

So sure, I don’t expect a hi-def video projection. But you can search the thousands of YouTube videos of both DIY and cheap manufactued video projectors and see the image quality, while not great, is far better than you describe.


You weren’t talking about the LED when you said this, you were talking about a short throw projector:
“I think if you were building an ultra-short-throw video projector on the cheap, these could work great!”
A short throw projector needs to have an optical system that outputs light at a large exit angle, not collimate light from a light source with large incidence angles.

Also I see absolutely no retail digital projectors that use fresnel lenses on google, other than people that made a diy projector with an overhead projector and laptop screen.
And the only reason the image is even usable is because the light is going through a massive LCD that is 15” in size or something, not a regular projector LED which is usually less than one or two inches.

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Enderman wrote:
LouieAtienza wrote:

Because the LCD screen will only allow light to pass through perpendicular to its plane the light has to be collimated to allow this. AFTER the light has left the LCD it is then focused on the projecting lens. You can argue about distortion all you want and are 100% right. But they’ve been making cheap projectors like this now for at least a decade. They’ve been using Fresnels in overhead projectors for decades.

As to Fresnel throwers… You can see in my pics I project an almost perfectly square die image – 200 yards into a brick wall. It’s rectangular now because I put a 2mm^2 in. I can’t capture it with my cell phone but at 40ft focused i could read the inscription on the MCPCB at 40ft. Possibly because the RLT moved on me and is illuminating the whole MCPCB.

So sure, I don’t expect a hi-def video projection. But you can search the thousands of YouTube videos of both DIY and cheap manufactued video projectors and see the image quality, while not great, is far better than you describe.


You weren’t talking about the LED when you said this, you were talking about a short throw projector:
“I think if you were building an ultra-short-throw video projector on the cheap, these could work great!”
A short throw projector needs to have an optical system that outputs light at a large exit angle, not collimate light from a light source with large incidence angles.

Also I see absolutely no retail digital projectors that use fresnel lenses on google, other than people that made a diy projector with an overhead projector and laptop screen.
And the only reason the image is even usable is because the light is going through a massive LCD that is 15” in size or something, not a regular projector LED which is usually less than one or two inches.

They must block such search results in Vancouver, otherwise you may attempt to rule the world…

Here’s some of dozens of YouTube videos:
https://www.youtube.com/watch?v=Rp8HIf5eUpo
https://www.youtube.com/watch?v=5SEuLMIfTzY&t=4s

And Instructables:
https://www.instructables.com/id/DIY-LED-Projector/
https://www.instructables.com/id/DIY-Multimedia-LED-Projector/

These guys tear down these Fresnel projectors:
https://www.youtube.com/watch?v=bomUYpEEgtw
https://www.youtube.com/watch?v=pm6SRNn9iAE&t=446s
https://www.youtube.com/watch?v=itrc38JgvRk

Looks like Fresnels on both sides to me. My thought was to put the short focal range Fresnel on the front past the LCD.

I emphasize the phrase “video projector on the cheap.”

I’ve been around bowling for about 25 years. Back in the day they did not have computerized automatic scoring like they do now – automated scoring came about just before I started. What they did what give you a transparency with the score boxes and a yellow wax pencil. You set the transparency on the “Tele Scorer” which is basically an overhead Fresnel projector with a Fresnel underneath the table and overhead in a box with a mirror inside to face the projected image forward onto a screen.

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OK, here’s a Fresnel lens designed to collimate 14 LEDs:
https://www.alibaba.com/product-detail/Low-cost-Micromu-WM-063240-dia_60...

What performance would I expect from it?

  • cheap plastic fresnel = bad throw
  • lots of beam artefacts from LED cross-talk i.e. shining at the neighbouring lenses

OK, I don’t think this particular lens is good.
But I find the general concept of multi-LED aspheric VERY interesting.

But first one would need to solve the crosstalk issue.
It’s easiest to do with baffles. With a proper baffle system between the LEDs there would be no crosstalk whatsoever.
But what if the baffles were actually collars, carefully machined to have the right aperture shape?

One could build a multi-LED thrower (actually I wouldn’t prefer 14 except for huge lights. 3 would be more like it) with

  • high output
  • very high throw (collars!)
  • high efficiency
  • quite short focal length

Unlike multi-LED TIRs or reflectors (I’ll call them T/R) – these have no dead zones i.e. ones that don’t produce throw. However:

  • with fresnels reflection off ridges costs throw. And precision tends to be lower
  • with convex lenses – I strongly suspect the valleys between individual lenslets wouldn’t be very precisely made.

So the loss structure is different from T/R. It scales differently, f.e. 3-up is quite bad with T/R and should be good here. OTOH 7-up is quite good with T/R.

EDIT:
Again, I post here and within minutes stumble upon just the same kind of stuff. This time I got email with this:

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You can buy adhesive backed vinyl with Fresnel patterns and metalized coatings behind; they use it for decorative stuff as well as cut for letterings and stuff with a prismatic effect. Which got me thinking… probably not practical, but one could do the opposite – take a Fresnel with a parabolic profile, put a reflective coating, and have a parabolic reflector that is essentially flat…

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Agro wrote:
OK, here’s a Fresnel lens designed to collimate 14 LEDs:
https://www.alibaba.com/product-detail/Low-cost-Micromu-WM-063240-dia_60...

What performance would I expect from it?

  • cheap plastic fresnel = bad throw
  • lots of beam artefacts from LED cross-talk i.e. shining at the neighbouring lenses

OK, I don’t think this particular lens is good.
But I find the general concept of multi-LED aspheric VERY interesting.

But first one would need to solve the crosstalk issue.
It’s easiest to do with baffles. With a proper baffle system between the LEDs there would be no crosstalk whatsoever.
But what if the baffles were actually collars, carefully machined to have the right aperture shape?

One could build a multi-LED thrower (actually I wouldn’t prefer 14 except for huge lights. 3 would be more like it) with

  • high output
  • very high throw (collars!)
  • high efficiency
  • quite short focal length

Unlike multi-LED TIRs or reflectors (I’ll call them T/R) – these have no dead zones i.e. ones that don’t produce throw. However:

  • with fresnels reflection off ridges costs throw. And precision tends to be lower
  • with convex lenses – I strongly suspect the valleys between individual lenslets wouldn’t be very precisely made.

So the loss structure is different from T/R. It scales differently, f.e. 3-up is quite bad with T/R and should be good here. OTOH 7-up is quite good with T/R.

EDIT:
Again, I post here and within minutes stumble upon just the same kind of stuff. This time I got email with this:
!{width:60%}http://www.luximprint.com/wp-content/uploads/2018/06/Luximprint_Flys-Eye...!

You can be an insect…
https://en.wikipedia.org/wiki/Compound_eye
And buy the lens…
https://www.ebay.com/itm/2PCS-PMMA-Plastic-Solar-Compound-Eye-Fresnel-Condenser-Lens-flys-eye-Projector/172776821991?hash=item283a4d14e7:m:m56oxVLbcGj3sDGDUxDgC-g

Xandre
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Sorry,
but this lenses are bullshit.

Ok for flood and many many Leds
but not worth to make a custom build with a lot of work…

The lens is good to protect from dust.
Another advantage I can not see.

Just my 2 cents !

Regards Xandre

Agro
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LouieAtienza wrote:
Agro wrote:
OK, here’s a Fresnel lens designed to collimate 14 LEDs:
https://www.alibaba.com/product-detail/Low-cost-Micromu-WM-063240-dia_60...

What performance would I expect from it?

  • cheap plastic fresnel = bad throw
  • lots of beam artefacts from LED cross-talk i.e. shining at the neighbouring lenses

OK, I don’t think this particular lens is good.
But I find the general concept of multi-LED aspheric VERY interesting.

But first one would need to solve the crosstalk issue.
It’s easiest to do with baffles. With a proper baffle system between the LEDs there would be no crosstalk whatsoever.
But what if the baffles were actually collars, carefully machined to have the right aperture shape?

One could build a multi-LED thrower (actually I wouldn’t prefer 14 except for huge lights. 3 would be more like it) with

  • high output
  • very high throw (collars!)
  • high efficiency
  • quite short focal length

Unlike multi-LED TIRs or reflectors (I’ll call them T/R) – these have no dead zones i.e. ones that don’t produce throw. However:

  • with fresnels reflection off ridges costs throw. And precision tends to be lower
  • with convex lenses – I strongly suspect the valleys between individual lenslets wouldn’t be very precisely made.

So the loss structure is different from T/R. It scales differently, f.e. 3-up is quite bad with T/R and should be good here. OTOH 7-up is quite good with T/R.

EDIT:
Again, I post here and within minutes stumble upon just the same kind of stuff. This time I got email with this:
!{width:60%}http://www.luximprint.com/wp-content/uploads/2018/06/Luximprint_Flys-Eye...!

You can be an insect…
https://en.wikipedia.org/wiki/Compound_eye
And buy the lens…
https://www.ebay.com/itm/2PCS-PMMA-Plastic-Solar-Compound-Eye-Fresnel-Condenser-Lens-flys-eye-Projector/172776821991?hash=item283a4d14e7:m:m56oxVLbcGj3sDGDUxDgC-g


I have seem those microlenses before. But macro? These are the only 2 that I’ve seen so far.
Agro
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Xandre wrote:
Sorry,
but this lenses are bullshit.

Ok for flood and many many Leds
but not worth to make a custom build with a lot of work…

The lens is good to protect from dust.
Another advantage I can not see.

Just my 2 cents !

Regards Xandre


I’m not sure which lenses are you referring to? The multilens + collar concept or the microlens array?
Agro
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Fenix E16 is known for its unique flat optics. This kind of optics is called RXI and quite popular in literature but nearly completely absent from the market. It seems to stifled by patents.

I found 2 makers that manufacture such optics. Neither looks like the Fenix one so there are surely more.

GR Optics has a family of COB lenses from 35 mm to 91 mm

Light Prescriptions Innovators makes a 41 mm lens:
http://www.lpi-llc.com/Data%20Sheets/LPIPN-RXI4104LL01.pdf

Soraa uses RXI in their bulbs:
https://www.archlighting.com/technology/leds-understanding-optical-perfo...

Some paper that I liked, they fold light path RXI-style with refraction alone:
https://pdfs.semanticscholar.org/e0b0/ad7628e5d6f273532cb57d2a4a9356e096...

Enderman
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Agro wrote:
Fenix E16 is known for its unique flat optics. This kind of optics is called RXI and quite popular in literature but nearly completely absent from the market. It seems to stifled by patents.

It’s the same as this, just worse.
http://www.mtnelectronics.com/index.php?route=product/product&path=68_12...

And it’s called a catadioptric.

Agro
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Oh, I forgot that lens. It seems to indeed use the same working principle. Except that Carclo has really low transmission, I suppose it spills light everywhere. That’s not the case with metallized reflector lenses.

LouieAtienza
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The Fenix looks more like a hybrid reflector than a catadioptric. The hybrid reflector has a TIR that directs the light from the LED into the reflector. Polymer Optics makea then with aluminum reflector and plastic TIR. Auer in Germany makes them out of glass.

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