I have done a quick search about transparent anti-reflective film and found certain information, although I'm not going to go on with it now because at this moment we certainly don't know what type of technology are you speaking about or can get a hold of.
However what I can certainly say is that if you can get some example lenses, from what I can see here in post #5463 it is clear that you can certainly test them to know if they will be liked. The goal is:
Lenses or lens coating must not raise Duv; if they lower Duv a tiny bit it can be nice.
Beam CRI or CRI with the lens on must be as good as it is without lens (R9 should not go down, and etc.).
Just in case, without any sort of testing it can be clearly understood that uncoated quality lenses meet both conditions. O:)
I have a question, which is a sincere question. What is the purpose of anti-reflective coating on our flashlight lenses? Is there some kind of glare that it eliminates ? If so is it glare on what we are lighting up or from the lens itself?
To my knowledge, it is used in order to get more light through the lens. Otherwise, some of the light would reflect back into the flashlight itself instead of going out the front. A lot of AR lenses are claimed to have ~99% transmittance. Uncoated glass is less. How much less, I’m not sure (maybe 5% less?).
The point is the driver board, which is not a FET, but a constant current. As long as the driver board is completed, the rest of the work will be done quickly.
The manufacturer has done samples three times, but each time the samples are done, it turns out that it is very difficult to purchase chips. The supply of chips is extremely unstable this year.
I want to temporarily remove the reverse charging function.
Have you thought about developing flashlights with dual diodes and dual batteries? For example 2*LH351D/2*14500 or 2*50XHP/2*21700 and many other options.
I have already seen many such inexpensive flashlights on Aliexpress, apparently there are factories that can make such cases from aluminum at an affordable cost.