Project Excalibur - Next Generation LED Thrower (many pics) - UPDATE 2018-01-24

EasyB you’re correct, this is basically the reverse of a wavien collar+lens, however there are several reasons why this would be worse.

1) the main optic diameter will remain large, since the spherical reflector takes light from the middle rather than the sides.
Something I think is very important is not just getting high lux, but getting high lux per diameter of optic.
Anyone can take a big lens or reflector and put it in front of an LED to get big numbers, but the impressive thing is getting BIGGER numbers with the same diameter, or similar numbers with a smaller diameter.

2) The collar the way you drew it would only collect very little light, resulting in an intensity increase much less than 2.2x like the wavien collar does.
In order for it to be equivalent to the wavien collar, your spherical reflector would need to be collecting 120 degrees, and your main reflector would need to be much flatter and collect 30 degrees on either side.
Again, this would result in a large diameter of main optic.

3) You can see in the drawing that the parts of the reflector near the bottom are still very close to the LED.
This will be contributing to a big corona and less-sharp spot projection.
With a lens, all the surface where the light hits is farther away, giving a tighter beam and smaller spot.

What difference does a “sharp” spot make? More candela is always more candela. And the collar is doing exactly what you say - improve candela for a given optic size.

@easyb
That looks good. I guess I had an error in my thinking.

Just so you guys know - I am not actually interested in this for this light. I actually want the little bit of dark spill light it produces.

Yes it would increase the intensity, but my point is that you can get a bigger performance boost by using a different type of main optic when using a collar :slight_smile:

Another problem (I made the same drawing a few years ago :party: ) is that in order to prevent blocking the reflected light from the reflector, the mirror must be small and close to the led, so with short focal length, resulting in a larger reflected image than you want (unfortunately the led die is not infinitely small so the projection is an image, not a point), I assume larger than the die you want to project it back on.
Edit: no, it must be just as large since the source distance is the same as the projection distance. I guess??

With a spherical reflector over an LED the image is always the same size as the LED :slight_smile: just inverted.

For wavien collars it doesn’t seem to matter much which size you use (if the LED is small). The luminance gain is almost the same (the small one is more difficult to focus though).

I finally remembered to calculate this. It was easier than I thought, all you need is Pythagoras’s theorem for triangles since I already now the diameter of the reflector and the maximum focal length (94mm).

So the depth of the reflector is 73.2mm (distance from lens to focal point, straight down).
The real depth all the way to the bottom I don’t know yet, maybe an additional 15mm.

Excellent work! :student:

Congratulations! I had not seen it, thanks for sharing :slight_smile:

Thanks!

Hi Gaston,

Where is your wavien build? The Driver is making a list of furthest throwing lights in a world and your is also probably in top 20.

Hi luminarium iaculator,

Is an old thread! here it is:

It would be good to do a ranking :slight_smile:

OMG the Detail and work for this project. O…M…G…

And I can only think of one name for it.

UBERThrower

I have added it to my “ranking” here. :+1:

So, who is going to put a Black Flat into his BLF GT to try to beat this light?

sma tested the Osram Q8WP here (a source in China has surfaced) and unfortunately two of his only reached 190-206cd/mm^2 (same as the old XP-G2 R5/S2). It seems they are of the lowest possible Bin and thus very inefficient.

There is a different Osram LED though which has a higher luminance than the Osram Black Flat, the Osram Synios P2720 DMLN31.SG. This test showed that it can produce up to 297.8cd/mm^2, which is 20% more than the Black Flat. It's downside is that it only produces 200 lumens and the small Die creates a tiny spot (0.225mm^2). I think it's too small and dim for this light though. The Black Flat itself is rather dim...

Where did he get the Q8WP from??
All the distributors show 0 stock…

Be more creative ;).
https://www.yoycart.com/Product/547738518217/
Yoycart is a Taobao agent who has an English website showing which products he offers. This makes it much easier compared to buying on Taobao directly (only Chinese).

Huh, interesting.
How do we know that it’s not an old Q9WP being sold as Q8WP?
If no reputable distributor like mouser or digikey have it, why would this site have it?
https://octopart.com/search?q=UW+Q8WP

EDIT- I just found it available here actually, must have recently become available :slight_smile:

Impressive, don’t know how I missed this thread until now.

That’s easy to tell: the newer Q8WP has four bond wires, the older Q9WP only has one.

The big distributors don’t have it because nobody orderered a reel from them yet. That’s what the first buyer has to do.

Thanks for the heads-up concerning RS. :wink:

Yeah, RS has the NAPA bin in stock, also the lowest, but what’s interesting is that there is a “V2” version which is rated for 6000mA rather than the default 1400mA, even though it shows the same lumen values.

Maybe they just used the default lumen value from the datasheet but the LED can handle higher currents?
If they get some in stock I might buy one of each and compare them, but they will arrive in de cember so maybe by then we can find NBPB or higher bins.