agreed, i tried sourcing one but couldnt find any, i also looked into buying a small s[herical or elliptical reflector but couldnt figure out the exact geometry id need
screw based is great because your adjustability is almost infinite, just gotta be careful how you implement it. if you rely on the screw for posiion and structure it might get difficult to adjust
i considered a design with threaded holes in my heatisnk and a spring to keep the screw tensioned. that screw would control position and would be behind the heatsink pulling it backward. then when the right position was found i was going to have channels running perpendicular to the lens plane that i could put a screw through and lock the heatsink in place
happy to measure and provide estimates, but im not sure how, i dont currently have an integrating sphere
could maybe measure the difference in energy absorbed by a black piece of metal when comparing with the lens vs without - but thats quite an involved setup
update
spoke to a coworker - very doable but will take a couple days. ill probably be back with another guide and writeup for a cheap way of measuring optical losses
should be able to use the light to heat a insulated piece of metal - once it hits equilibirum i can use a thermocouple to get a voltage readout which is linearly related to temperature which is related to energy - then take a % difference in voltages and compare the % difference. i will NOT get any units of energy from this but i could if i put more work into it. if i do calculate energy it would be very cool to measure energy leaving the battery and energy in the beam
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Just researched the wavien collar idea. It’s a bit strange that reflecting all that light back onto the LED would actually generate more light (diffuse reflection?) instead of what I imagined (it would just get absorbed and cook the LED chip).
I wonder if you can get some manufacturer to make some. The PVD coating is hard.
I will think a bit more about screw based adjustment. Springs on the threaded rods and 1 nut per corner might have to be the way.
No big deal about measurements if it’s too much work. The heating up metal idea is interesting…
I think the measurements would also be of use for the thread about zwb2 filter efficiency
And I’d like to compare different reflectors and TIRs and optics to see the losses
Added spacer to widen the lens and a shadow shape (M)
Unfortunately the shadow doesn’t show up so clearly, id probably need a precollimation lens to get a clear image
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