NewBie
*Retired*
Well, I got home less than an hour ago, and just as I'd been hoping for, my first production Seoul P4 LEDs had arrived.
I know these are a hot item for many, so without any delays, lets get some photographs.
Photographing these was a real pain, as the very, very soft gummy bear surface acts like a powerful dust magnet. I'd clean it, get it set up for a photograph, and it would have new dust specks on it, so after three tries, I finally gave up. Unfortunately, I don't have a laminar flow bench to give me filtered air.
These LEDs are rather cloudy, so I had to play a few tricks with lighting, to get an okay image.
Focused up off the die at the top of the phosphor, notice the tint variation across the die area:
I fitted one of these to a SO27XA, which isn't the smoothest reflector (I'll get it in a more perfect reflector later) which hides a number of the tint issues since the surface is rather distorted, but it was something that I could quickly get pictures of. Due to the tint variation of the image, and AWB, the camera tint kept changing slightly between shots:
For the white wall crowd, I apologize, the camera doesn't render tint variations near as well as the human eye, but that is a common shortcomming of digital cameras. The distorted SO27XA did a decent job of mixing up the tint, so the distorted reflector actually helps. I'd *highly* recommend one of McGizmos textured reflectors. The "tintyness" of the beam is probably second only to the Nichia Jupiter and Nichia 5mm LEDs- but quite a bit better than the 5mm LEDs.
So, where does the tint variation within each beamshot come from? This image should help explain that, it is the bare emitter shinning on a piece of paper:
For fun, I used a high end camera lens to image the LED on a wall, and took a photo of it:
With some of the smooth reflectors, I could see artifacts of the bond wires on the wall, reminds me a little bit of the hotwires. I'll see if I can get a photo of it if I have time later. Again, I'd *highly* recommend one of McGizmos textured reflectors to help out with this!
Even though this LED uses the same CREE EZ1000 die as the CREE XR-E LED, the way the optics were done, it emits much more of it's light sideways, so you have a very substantial drop in flood brightness in a reflector. But, conversely, with so much more of the light going sideways, more of it is directed forward, so this will be great news for those folks who like burning bright hotspots which throw better. Unfortunately, if tint variations within your beam bother you, you'll need to use a textured reflector to hide them, which will cause the throw to suffer.
With an aspherical lens, with a much higher porportion of the light going sideways out of the P4, substantially less hits a given sized lens, so less will be directed forward, as compared to the CREE XR-E.
Another drawback of this LED is that the slug is shorted to the positive side, where nearly every flashlight has a negative body. If the heatsink spot isn't isolated with anodizing, you will need to come up with a method of isolating the slug (hurts thermal performance- unless you are clever), or risk blowing up your LED and also the flashlight converter.
Be careful with the dome lens on the Seoul P4, it is very easy to damage the very soft gummy dome.
I think we got *really majorly* spoiled with the Luxeons, which had very little if any tint variation at all within the LED. IMHO, the magic trick for the Seoul P4 is the rough textured McGizmo reflectors. With *plenty* of extra lumens as compared to the Luxeons, you can easily afford to use a rough reflector to blur the tints, IMHO- unless you need every single lumen possible in a tight spot. Personally, I prefer spots that fade, instead of sharply cutting off.
Anyhow, I've got more testing to go do...
Some tidbits from later points in the thread (plenty of other things to dig in the thread if you are interested):
The above graph has too much data on it to see clearly, so if you are interested, download the larger version:
http://www.molalla.net/~leeper/sp4int3.png
I know these are a hot item for many, so without any delays, lets get some photographs.
Photographing these was a real pain, as the very, very soft gummy bear surface acts like a powerful dust magnet. I'd clean it, get it set up for a photograph, and it would have new dust specks on it, so after three tries, I finally gave up. Unfortunately, I don't have a laminar flow bench to give me filtered air.
These LEDs are rather cloudy, so I had to play a few tricks with lighting, to get an okay image.
Focused up off the die at the top of the phosphor, notice the tint variation across the die area:
I fitted one of these to a SO27XA, which isn't the smoothest reflector (I'll get it in a more perfect reflector later) which hides a number of the tint issues since the surface is rather distorted, but it was something that I could quickly get pictures of. Due to the tint variation of the image, and AWB, the camera tint kept changing slightly between shots:
For the white wall crowd, I apologize, the camera doesn't render tint variations near as well as the human eye, but that is a common shortcomming of digital cameras. The distorted SO27XA did a decent job of mixing up the tint, so the distorted reflector actually helps. I'd *highly* recommend one of McGizmos textured reflectors. The "tintyness" of the beam is probably second only to the Nichia Jupiter and Nichia 5mm LEDs- but quite a bit better than the 5mm LEDs.
So, where does the tint variation within each beamshot come from? This image should help explain that, it is the bare emitter shinning on a piece of paper:
For fun, I used a high end camera lens to image the LED on a wall, and took a photo of it:
With some of the smooth reflectors, I could see artifacts of the bond wires on the wall, reminds me a little bit of the hotwires. I'll see if I can get a photo of it if I have time later. Again, I'd *highly* recommend one of McGizmos textured reflectors to help out with this!
Even though this LED uses the same CREE EZ1000 die as the CREE XR-E LED, the way the optics were done, it emits much more of it's light sideways, so you have a very substantial drop in flood brightness in a reflector. But, conversely, with so much more of the light going sideways, more of it is directed forward, so this will be great news for those folks who like burning bright hotspots which throw better. Unfortunately, if tint variations within your beam bother you, you'll need to use a textured reflector to hide them, which will cause the throw to suffer.
With an aspherical lens, with a much higher porportion of the light going sideways out of the P4, substantially less hits a given sized lens, so less will be directed forward, as compared to the CREE XR-E.
Another drawback of this LED is that the slug is shorted to the positive side, where nearly every flashlight has a negative body. If the heatsink spot isn't isolated with anodizing, you will need to come up with a method of isolating the slug (hurts thermal performance- unless you are clever), or risk blowing up your LED and also the flashlight converter.
Be careful with the dome lens on the Seoul P4, it is very easy to damage the very soft gummy dome.
I think we got *really majorly* spoiled with the Luxeons, which had very little if any tint variation at all within the LED. IMHO, the magic trick for the Seoul P4 is the rough textured McGizmo reflectors. With *plenty* of extra lumens as compared to the Luxeons, you can easily afford to use a rough reflector to blur the tints, IMHO- unless you need every single lumen possible in a tight spot. Personally, I prefer spots that fade, instead of sharply cutting off.
Anyhow, I've got more testing to go do...
Some tidbits from later points in the thread (plenty of other things to dig in the thread if you are interested):
The above graph has too much data on it to see clearly, so if you are interested, download the larger version:
http://www.molalla.net/~leeper/sp4int3.png
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