Efficiency - yes, a bit. Out of focus Fresnel nearly touching the LED would add like 1.x mm to the total thickness.
You can’t use lenses like that.
They need to be a distance away otherwise the light will reflect rather than refract.
Most of the light will just bounce off the lens at that distance.
Might as well make it a mule at that point because nothing will get collimated.
Thanks, that’s an interesting input. That would require this light to be a couple of mm longer. But still, seeing the propotions that Haikelite HT08 has (diameter to mounting distance) I see that such optics won’t be as large as a regular TIR. But likely larger than Fenix E16.
Ignore the blue line, that’s only for polarized light.
Usually you don’t want to do anything more than ~45-60 degrees incidence angle.
You’ll have a hard time finding any lenses with a focal length closer than that, because nobody wants to lose 25%+ of the light that’s supposed to enter the lens.
And that’s not taking into account all the light that doesn’t hit the lens in the first place, since LEDs emit in 180 degrees.
If you want a low profile optic that doesn’t waste huge amounts of light, it needs to be a TIR.
This is how olight gets a nice beam for their flashlights while having some of the shortest lights per battery size.
If you want shorter, a mule is the best option, even better if the LED is flat like an XPL-HI or black flat.
Nice, I knew that such charts could be generated, but I haven’t seen them before.
The way I understand the chart:
- To get real reflection-loss coefficients for a LED emission one would have to integrate that over the lobes:
- When a lens is far, it captures the angles which have low reflection. Light coming at other angles hits flashlight walls and is wasted.
When a lens is near, it captures most of all light. The light that comes at low angles has low reflection, the light that comes at high angles sees significant reflection, the light at very high angles hits the walls and is wasted. Therefore a lens closer to the LED will have higher efficiency. - Does your advanced calculator take that reflections into account? They apply to AR coated lenses as well, though I suppose the charts are different and depend on the coating.
Still, the Olight example is interesting. It’s of similar diameter to this proposal. It’s just as small as lights that use non-Fresnel aspheric lenses. So it’s maybe a couple of mm longer than a Fresnel aspheric. Quite compact and definitely feasible.
A better way of sealing: just mold a plastic around it. Not just melted plastic because temperature would be too high for the battery. Use something chemically setting. Much better look, much tougher, fully water resistant.
- Yeah, but you only need to consider 1 lobe since the lobe is already a 2d representation of the 3d light distribution (do not think of it as a 2d slice through the LED)
So the total area of 1 lobe is 100% of lumens, The area of the lobe between 0 degrees and 60 degrees is 75% of the area aka 75% of lumens, etc etc etc
2) Correct, having a lens closer will result in higher luminous efficiency until the angle of incidence hitting the lens gets to about 45-60 degrees and then instead of entering the glass it starts reflecting off.
3) My calculators assume 100% of the light from the LED enters the lens but then is multiplied by an efficiency value to take into account the light absorbed or reflected by the lens.
It does not take into account reflection at large incidence angles, that’s something that is usually accounted for in the lens efficiency on the specs.
Unless you have angles of incidence greater than 45 degrees any losses from reflection are negligible.
Sun, 06/10/2018 - 18:07…………. #588
Is there any update on the whereabouts of the $486.37 that is supposedly still in this fund??
Well, I'm not sure. I could be confused but I know there was some money offerings but it was gonna be split like 10 ways or something, so I think The Miller gave us the option to take the money or donate it. I think a good deal of it went to O-L's widow fund, or maybe to giveaways - can't recall exact details. Most of us opted for that. Maybe others can confirm or recall better.
This as far as I know.
That was done in the BLF Q8 project at the end & has nothing to do with the money this thread is about.
The money in this thread was donated specifically for “Future Projects”. There was no split among ‘Team Members’ with this money because this does not involve a specefic team.
So, according to the accounting record in the OP , there is supposed to be $486.37 in this account.
Either the accounting record needs to be set straight, if it is not correct; or the money needs to be surrendered so it can be put to good use as TA suggested well over 6 months ago.
….
Edit: HERE IS A LINK to the “Affiliated Link” money distribution accounting at the end of the Q8 project that was mentioned above.
Again, this has nothing to do with the money in this “Future Projects” account.
Ok, I guess you are right there. Well as you can see, The Miller hasn't been on for 9 months so we may not ever get an answer. I believe I have an email address for him - I could try contacting him.
First, I’m convinced that there is no bad intent from The Miller. He disappeared from BLF overnight (like many others did) and with him the administration of this fund went away from sight.
I had brief contact with him later and it seems nothing terrible happened to him that made him leave BLF.
I’m also convinced that he knows that the consequence of his disappearing for this fund is that in fact the fund is frozen until he does something.
But doing something implies new involvement in BLF for him, which may be a difficult thing if he was all of a sudden completely fed up with the loads of responsibility that he took, left without finishing and know that people were disappointed about that. (this is how I can imagine things went, I never heard the reason for his leave).
We may contact him for this, or we may wait for him to arrange a solution for the fund. It is not that anyone is waiting for the money right now.
He didn’t get fed up or anything like that. He got really sick for like a month, then had the maintenance work at his bed and breakfast pile up. Then there was a flood on the property requiring even more of his time. His health may have relapsed again for a while.
I’m guessing that being off the forum for so long might have been a relief and that it was hard to get back into the swing of things so it was better to stay off. IDK, but seems plausible.
Thanks for the extra info Jason.
I feel confident there was no bad intent either.
But it has been 15.5 months since this post has been updated. It is past time for this to be taken care of one way or the other. Whether the OP takes care of it himself or deligates someone to handle it makes no difference.
People donated to this fund in good faith for the development of ‘Future Projects’, the administration of the fund should honor that good faith.
If it is simply a matter that the OP has not been updated with more expendatures, update it or deligate someone to update it.
If the accounting is up to date in the OP, then either start administering it or delegate someone to.
As TA mentioned over 6 months ago…. he could have used some of this money in developing ‘Future Projects’. I am sure there are others that could have benefited in the same way developing ‘Future Projects’.
In the spirit of transparency, below is a copy of an email I just sent to The Miller at the only email address I have for him. Hopefully he is doing well & in good health and will address this matter when he sees fit.
………….
Subject: Item needs attention….
Hello Wim,
I hope this email finds you doing well & in good health.
There is a matter at BLF that needs your attention.
It is the thread you started about “Future Projects Donations”. It has not been updated since 1 October 2017. It shows a balance of $486.37.
If this is not correct, please update with the correct amount or delegate someone to do so.
If it is correct, please either start administering this fund or deligate someone to do so
Below is a link to the thread and the accounting summary when last updated 1 October 2017.
Again, I hope you are well & in good health.
Best regards,
Chuck
…………
‘Talk about future projects and donation topic’
BLF DONATIONS OVERVIEW
Total input 830,52
Total spend 344,15
Funds left 486,37
Ok, sounds fine to me....
/\…… 
I just sent an email to him as well, little more personal but along the same lines, CC'ing djozz and MrsDNF. Sorry to leave anyone out but feel strongly that djozz and the Mrs should be included.