A parabolic reflector has a given shape and proportions.
The one he uses to design a light around is way off.
The LED is not in the focal point, he’s using an incan light reflector model.
Iḿ sorry, but just look at the picture.
Do you think i should not have pointed this out?
And as i said, it does explain the different basic shapes between his and my designs.
Lets put a 23mm-35mm floating lens in front of the led. So it will focus the die to infinity. If we can find a lens that has the required focal distance and diameter we can even attach it to the front glass. Or below it.
It will be a form of large TIR optic that forwards most of the light straight forward.
We can calculate which part of the led light is wasted in spill and project that forward. And how big of a diameter lens we can put on a given focal length.
Balancing definitely helps, but keeping it compact helps even more.
Just imagine controlling a 30cm (1 foot) long pole weiging 1kg (2 pounds) versus a 2 meter long pole of the same weight. The longer pole requires a lot more force and energy to control when swinging around.
Let’s just agree to disagree; no hard feelings from my side, but this project (the way it’s turning out) just isn’t for me.
Sooo, basically you want a 1Mcd+ thrower, to illuminate objects at very large distances, and you also want to be able to flick it around in an instant? Really? Why?
We have decided to gor for a 120 mm reflector hundreds of posts ago, and now we opt for a pre-collimating lens and a aespheric lens or a hughe TIR optic?
Don’t you think this will make the flashlight “a litte bit” more expensive and, with a TIR lens that big, quite a bit more heavy or (if plastic) more prone to lens-scratches?
It does sound very interesting, but please keep the basics of this project in scope: low cost, easy to manufacture etc………in other words doable.,
But hey, maybe next BLF thrower project can be a massive pre-collimating + aespheric torch? 2Mcd perhaps?
No, you’ve made a good point.
But he already knew it, and so he put a disclaimer in his post saying exactly what you mean.
Though, if he would tweak his design to suit the reflector it would only be some minor tweaks. So not a big deal imo at this point (which is all about outside design)
Alright, I’ve redraw my design so I could run a thermal simulation. Here is the result:
As I said, I’m not sure how accurate it is since this is the first time I did this. However i think this give us a good representation about how it will perform.
This is with a 40watt load distributed along the led shelf. Imaging that the MCPCB will evenly distribute the entire 40 watt load on the shelf.
Thermal convection coefficient is 20W/ (m^2.k), I really dont know what that means but its a good number for natural air convection. (like walking around outside I guess)
Ambient temperature is 300 kelvin around 30 degrees celcius.
I’ve run another simulation with a convection coefficient of 50W/ (m^2.k) and that gives a 20 degrees celcius difference (cooler).
It was just an example to help with realizing that size matters.
Small adjustments of something well balanced won’t be too hard, but keeping the length down helps quite a bit over time.
If you want performance i would say recoil reflector set up.
Problem though, is finding a decent and affordable 5 inch reflector that can take at least 120° from the LED.
