Effect of Aspheric on 7 LEDs

What sort of effect would i likely get if i added a 60mm ish diameter aspheric lens to my 7 cree dive light build?

Would i just get 7 tightly packed hot spots, or 1 very bright but wide beam or even an amazing throw single beam?

Im using fraen 19mm reflectors on XRE Q5's packed in 2,3,2 lines.

What about if i take the refelectors off?

Cherrs.

Re: Affect of Aspheric on 7 LED's

7 spots, the centermost ones tighter than the outter ones. IMO.

You could do what member Packhorse did, and get some DX aspherics,and put an aspheric in each led, you might get a brighter single beam. look up his tread.

HTH
AlexGT

Re: Affect of Aspheric on 7 LED's

gav6280 said:

What sort of effect would i likely get if i added a 60mm ish diameter aspheric lens to my 7 cree dive light build?

Would i just get 7 tightly packed hot spots, or 1 very bright but wide beam or even an amazing throw single beam?

Im using fraen 19mm reflectors on XRE Q5's packed in 2,3,2 lines.

What about if i take the refelectors off?

Cherrs.

Click to expand...

One sharply focused spot in the middle, surrounded by 6 separate spots, that will be very rapidly diverging away from the main spot.

Im just guessing here but I thing you would end up with a very diffused light with no spots at all.

Why?

If the convex part of the lens is exposed to water then the water will defract the emitted light and change the focus.
You would have to put a flat lens over the front of the aspheric but as the other posters have pointed out you will just end up with 7 spots. Im unsure what effect you would have from de focusing the lens. That may help but you will still need the flat lens for it to work under water.

What sort of head are you using?
If it was me I would consider using a mix of reflectors and aspherics. Perhaps with a 3 way switch so you could have either of them or all of them.

Custom design by a fellow CPF member.

Following documents should give some idea.
(Safe doc's hosted by myself)...

http://www.divelight.co.uk/Light%20head.jpg - Similar to this in looks.
http://www.divelight.co.uk/dive%20lights%20(1).pdf
http://www.divelight.co.uk/dive ligh rev 3.pdf

This is the 4 Led version, the 7 Led one will be the same just bigger..

Any other ideas on focusing 7 Led's into a very tight focusing and long throwing single beam?

Just one lens won't do the trick, unless it is like 600 mm diameter (the larger, the better) . Maybe too big for a dive light

You need separate lenses, one for each emitter... no other way to do it.

Using 20 mm aspherics, that should mean- including the housing- less than 80 mm OD, which is a compact design and bright enough to beat any 24 Watt HID.

Javier

TIR optics can be theoretically focused as tight as aspherics of the same diameter and TIR optics are a good bit more efficient. Also, TIR optics usually snap onto the LED, ensuring optimal placement.

If you angle the out side ring of the 7 led setup to meet the focal point of the middle one it would work IMO and may try with very tight reflector's' try with 3 on the outer ring one in the centre, convergance of all four or 7 equal to the focal length i think would work
cheers DocD

Very good point DocD!!

As I'm at home now I had not big lenses to test that, but with a 23 mm it has worked pretty good. The LED which is not on axis produces a kind of "comet tail" .. it is going to be difficult this way, but it works.

Javier

My guess: Theoretical might be possible for the gross part, but in real life almost impossible to achieve a decent beam. The shattering and spill is uncontrollable, though lots of the light would be center into a high-lux spot.

I say do it anyway and take lots of pictures!