Single reflector friendly triple emitter setup

Barkuti · 2018-07-21T03:07:09.000Z

Tinged in my mind a few minutes ago. Does not fit perfectly (circumscribes) to ∅9mm hole reflectors by a hair or so (had one at hand to test it, its maths anyway). Two die centers equidist from hole's center, the other is just a tiny bit farther away (can be fixed by spacing out dies evenly, for this in its more compact form the emitters below are to be separated 3.5mm / cos 30 - 3.5mm = 0.541451884329mm. Either this, or compact triangle formation with equilateral triangle hole at the center.

No board design yet, if someone wants to make it go ahead. Track layout for in parallel arrangement requires jumper. Board can be easily designed to allow both in series and in parallel arrangements.

Could make a really throwy triple, depending on reflector design I suppose.

Cheers :-)

P.S.: edited for a correction. Edited for another fixup and to add information.

Lightbringer · 2018-07-21T03:32:46.000Z

Just a slightly bigger hole and you can go quad instead of just triple.

https://www.aliexpress.com/item/10pcs-20MM-led-Cooper-PCB-Board-Led-Heatsink-Thermal-Separation-Led-Lamp-Base-For-4D-Cree/32812824554.html

Go crazy…

Barkuti · 2018-07-21T03:50:14.000Z

Lightbringer:

Just a slightly bigger hole and you can go quad instead of just triple…

Yes I know. A quad is more die size, this means less throw at the same power. Besides, those quads aren't space fitting optimized (been working on a couple, btw), there's more than ½mm of space between each led's solder pads, not ideal if we aim to gather the emitters as close as possible.

led4power · 2018-07-21T10:50:10.000Z

Large donut hole would appear and light would be completely unusable.

Barkuti · 2018-07-21T11:14:26.000Z

led4power:

Large donut hole would appear and light would be completely unusable.

I can live with donut holes but, unusable light?

led4power · 2018-07-22T09:59:06.000Z

Quad die emitters like XHP50 and XHP70 have quite visible donut hole when used with smooth reflectors, and their dies have ~0.5mm gap separation.

In your setup gap between dies are ~2-3mm? That would give you very large dark spot in center.

LumenHound · 2018-07-22T12:46:44.000Z

Mount the 3 emitters to the end of a 3 sided copper stem (or even a length of heavy copper wire) and see what kind of beam you get with modestly driven leds.

Tricky to do but side emitters may give you a tight flood beam.

eas · 2018-07-22T22:29:52.000Z

I have one of the 2x2 MCPCBs linked earlier in the thread. With a smooth reflector, it has a black hole in the center of the beam.

After DIYing an OP reflector by misting the stock reflector with enough clear gloss spraypaint to cover 75% of the reflector surface with a rough texture, the beam is even floodier and it still has a spot in the center. The spot isn’t anywhere near as dim as with the smooth reflector, but it’s still noticeable, maybe 3 stops dimmer.

I have some cheap optics for 7070 emitters on the way from China to try. And when I place my next Mouser order, I’m going to buy a couple variants of the Ledil Eva. The beamshots from the datasheet show that they do a great job of blending gappy quad-die emitters.

Lightbringer · 2018-07-22T22:35:23.000Z

Short of making it a mule, a nice aspheric should give a nice wide blanket of light.

LumenHound · 2018-07-25T03:55:21.000Z

Off on a tangent here,
If I recall, it was Mcgizmo back around 2005 when we were all on CPF who did the triple side emitter experimental ground work.
He posted beam shots as a work in progress and the results were impressive.

Barkuti · 2018-07-25T16:40:07.000Z

There's been a bit more chitchat here than expected. Interesting…

Problem here is fusing beams from emitter dies with are inevitably apart. I believe this can be sort of done to some extent, but the reflector must somehow be located off-focus (a little bit higher maybe) and the emitters should be placed making a sort of perfect geometric shape from the focus center. Like all 3 emitters at 60° from each other (isosceles triangle) and 60° rotated from each other (there would be an isosceles triangle hole right at the center).

Cheers

Barkuti · 2018-07-25T16:41:52.000Z

LumenHound:

… it was Mcgizmo back around 2005 when we were all on CPF who did the triple side emitter experimental ground work.

He posted beam shots as a work in progress and the results were impressive.

Any sort of information available?

Cheers :-)

LumenHound · 2018-07-25T21:28:54.000Z

Pretty sure all that info and beam shots were lost in one of the many fatal server crashes CPF suffered through way back then.
Think a reflector designed for an incan bulb with the focal point further away from the base of the parabola than typical led optomised reflectors was used.

LumenHound · 2018-07-25T21:39:57.000Z

Found it!
Don posted it on his site.
Double and triple side emitters

That website is a real walk down memory lane.

MRsDNF · 2018-07-25T21:51:46.000Z

LumenHound:

Found it!
Don posted it on his site.
Double and triple side emitters

That website is a real walk down memory lane.

I haven’t seen anything like that before… It was very interesting and shows the skills of the guy.

The_Driver1 · 2018-07-25T21:52:15.000Z

Barkuti:

LumenHound:

… it was Mcgizmo back around 2005 when we were all on CPF who did the triple side emitter experimental ground work.
He posted beam shots as a work in progress and the results were impressive.

Any sort of information available?

Cheers

http://dmcleish.com/CPF/

Specifically here, scroll down a bit.

DavidEF · 2018-07-25T22:01:03.000Z

That dual/triple side-mount LED trick is exactly what most LED Automotive Headlight makers do now. I had never seen that mod, but the man was ahead of his time.

EasyB · 2018-07-26T00:58:12.000Z

That side facing LED build is very cool. It looks like you have to shift each reflector section outward so the focus lies more on the LED. So this probably wouldn’t work (as well) with a single uncut reflector. Which is unfortunate because cutting and placing the reflectors looks difficult.

Redlyne22 · 2018-07-26T07:01:51.000Z

As DavidEF mentioned……

I’ve been eyeing these 12v triple/single spot lights for months now. I cant figure out if it’s a gimmick or the next step in led lighting. One thing that bugs me is heat management might suuuuk.

[3 new items added to shared album] Triple led single reflector spot light

Agro · 2018-07-26T08:22:19.000Z

LumenHound:

Found it!
Don posted it on his site.
Double and triple side emitters

That website is a real walk down memory lane.

Superb, thanks a lot for the link!