Mini-Mag reflector... with Luxeon! (pics)

[Mark_Larson]

So i had the bright idea a couple of weeks ago to mod the Mag reflector to use with my BB400/Q2 LD. I was happy with the NX-01 and McFlood, but wanted something more.

So yesterday night i started filing at the bottom and lip of the reflector. Last night it was just right, requiring just a little twist of the head to turn it on. Today i messed with it some more, and now it only switches off right where the head is tightly screwed down /ubbthreads/images/graemlins/frown.gif Loosening it even a little bit causes the light to turn on.

Looks like a Kroll is the answer, but can i do anything for the light before i spend money? I was thinking raising the height of the reflector is the answer, maybe by sticking something to the upper edge (base of the cone). What could i stick?

The performance is very good - although i don't think it is in full focus yet, there is a tight hotspot with an appreciable level of spill. And of course you can substitute the hotspot for a dark hole if you want a "flood" /ubbthreads/images/graemlins/icon15.gif

Here are the pics...

Trying to make it uniformly yellow...

Looking closer...

A little closer...

How it looks. I apologise for the total lack of focus.

 

[Mark_Larson]

Re: Mini-Mag reflector... with Luxeon!

Update... I filed some more, and made the hole bigger. Now it doesn't switch off at all /ubbthreads/images/graemlins/frown.gif

Some more pics...

Comparison with McFlood - look how short it is!

Shiny...

Also, for some reason, it doesn't drop further than a certain level. I filed the tabs on it, but it doesn't want to go down any further. Looks like this is the best focus i can get /ubbthreads/images/graemlins/frown.gif

 

[LED_ASAP]

Re: Mini-Mag reflector... with Luxeon!

I am totally surprised that you need to file down so much to get a focus.

One possible remedy would be to remove the LS, add a copper disk underneath, and re-epoxy the emitter---so you push down the sandwich a little more that it will shut off again.

 

[Mark_Larson]

Re: Mini-Mag reflector... with Luxeon!

[ QUOTE ]
LED mods As Small As Possible said:
I am totally surprised that you need to file down so much to get a focus.

[/ QUOTE ]
This was my first time - i suppose you don't need to file down so much. I originally just enlarged the hole (thus not changing the height) but then i read some posts on how it was better to file down the base (the apex of the cone) and sand away the lip. This i did, and although it did help the focus, i took away a little too much. /ubbthreads/images/graemlins/frown.gif

[ QUOTE ]
One possible remedy would be to remove the LS, add a copper disk underneath, and re-epoxy the emitter---so you push down the sandwich a little more that it will shut off again.

[/ QUOTE ] Now that's way over my head. /ubbthreads/images/graemlins/grin.gif

I'm still thinking of a way to increase the reflector's height... /ubbthreads/images/graemlins/thinking.gif

 

[kj]

Re: Mini-Mag reflector... with Luxeon!

When you get a focus, you will see the yellowish phosphor reflected in all over your reflector.

You can turn off your Mag by screwing down the head if you file the lip of the reflector to make it thinner. You will need an additional O-ring to hold the reflector in the head.

 

[Mark_Larson]

Re: Mini-Mag reflector... with Luxeon!

kj, if you can see the pics, you'll see that there is no lip left on the reflector /ubbthreads/images/graemlins/grin.gif

 

[kj]

Re: Mini-Mag reflector... with Luxeon!

Yes, I know /ubbthreads/images/graemlins/wink.gif As LED_ASAP pointed out, you probably filed away the bottom too much. It will work if you can file away a correct amount and I think it's easier than adding the height.

 

[Icarus]

Re: Mini-Mag reflector... with Luxeon!

kj,

Looking at your pictures it seems you're is focused!
Do you have a LD or HD Luxeon? How much did you file down?

I have a LD, drilled a hole of 6mm. Without filing is was out of focus. Then I filed down a little bit and it seems like the beam got more focused. Maybe I should file down a little more? What's the diameter of the hole in your reflector?

 

[kj]

Re: Mini-Mag reflector... with Luxeon!

I'm using HD. The dimensions of my reflector are:

[*]The total height is 9.55 mm.
[*]The diameter of the hole is 7.15 mm.
[*]The lip was filed down to 0.5 mm.

With LD, it seems we can't get a tight focus like HD. I would suggest filing the bottom of the reflector to make the total height 10.5 mm. If you file down a little more, it must not be a problem because you can adjust the focus by turning the head /ubbthreads/images/graemlins/smile.gif

 

[shankus]

I noticed a strange behavior in my MM+ R2H w/ darkzero's mini-Mag reflector today.

I had been noticing that the light had not been retaining the focus setting that I left it with. This was puzzling me until tonight. I turned it on, and left it on until I saw the focus change before my eyes.

Apparently, the heat transfer slug that the luxeon sits atop, expands as the luxeon warms up, pushing the LED up slightly, but enough to change the focus in a reflector. It starts to occur at ~20 sec., and continues until ~40 sec., when it stabilizes (ambient temp ~70°f).
I never noticed anything with the NX-05 or Fraen LP.

Have you guys notcied this anomaly?

 

[milkyspit]

Shankus, I don't have one of darkzero's reflectors but do have some thoughts on the change in focus that you saw. First, I'd find it strange if the aluminum slug itself expanded that much... plus that slug supposedly reaches thermal saturation in less than a second (or so I've been told), so maybe something else is the culprit. I wouldn't be surprised if the circuit board itself, or perhaps even the thermal epoxy, warped and/or expanded a bit when heated. As for not observing these with the optics, remember that those optics are typically pressed against the emitter itself (gently) when in focus, so they'd move with the expansion and everything would stay in focus, or just maybe they exert enough downward pressure to stop expansion in that direction. Not facts, just an educated guess.

 

[evan9162]

It's possible that the copper clad of the MM that the luxeon is mounted to is expanding faster than the coating on the other side, thus causing the PCB to flex upwards, both from the uneven expansion, and from the tailcap spring pressing up against the emitter board.