NewBie
*Retired*
I've photographed Royal Philips LumiLEDs Luxeon III devices, many times in the past.
I recently had some issues with anomalies in my photos that I was trying to take of the newer Luxeon III and thought it was my setup/camera, etc...
I was seeing weird effects like this:
You see where the tint changes from the center to the edges?
So I started scratching my head, trying to figure out what was going on.
Another weird thing in a shot:
It almost looks like a clump of phosphor was piled up on top of the die.
Imaging of the die on the wall with a lens wasn't working nearly as well as it used to.
So, I kept taking photos of the latest Luxeons I got, doing different things and kept getting the same results. So, I went and grabbed one of my lower output TWOH LEDs from 2003, and everything looked like it was "supposed" to, and as I remembered it in my photos.
So, I decided to try another tactic, and light the device externally, and found:
You will notice a lump of stuff on top of the die that is a slightly different color, above the phosphor!
I'm not certain as to what this is, but I suspect it is a higher index of refraction material, that is put above the die/phosphor in order to help extract more light out of the die.
Unfortunately, these newer U bin Luxeons seem to have a little bit more tint shift in the beam profile.
I recently had some issues with anomalies in my photos that I was trying to take of the newer Luxeon III and thought it was my setup/camera, etc...
I was seeing weird effects like this:
You see where the tint changes from the center to the edges?
So I started scratching my head, trying to figure out what was going on.
Another weird thing in a shot:
It almost looks like a clump of phosphor was piled up on top of the die.
Imaging of the die on the wall with a lens wasn't working nearly as well as it used to.
So, I kept taking photos of the latest Luxeons I got, doing different things and kept getting the same results. So, I went and grabbed one of my lower output TWOH LEDs from 2003, and everything looked like it was "supposed" to, and as I remembered it in my photos.
So, I decided to try another tactic, and light the device externally, and found:
You will notice a lump of stuff on top of the die that is a slightly different color, above the phosphor!
I'm not certain as to what this is, but I suspect it is a higher index of refraction material, that is put above the die/phosphor in order to help extract more light out of the die.
Unfortunately, these newer U bin Luxeons seem to have a little bit more tint shift in the beam profile.