LED emitters

The heart of any LED flashlight or headlamp is the emitter. These days (early 2010), it seems that Cree is making the best parts. Here is my attempt at a roundup and summary of LED technology:

Cree

You can get lots of technical data from the Cree website.

XR-G A 3.45 by 3.45 mm die with a 325 lumen output (for the R5) - R4 and R5 designate flux bins. The data sheet says it is "capable of 493 lumens at 92 lumens per watt when driven at 1.5 amp." This is the "XLamp XP-G LED", some people call it the "7090 XP-G", but I have no idea where the 7090 comes from.

XR-E A 3.45 by 3.45 mm die with 220 lumen output (for the R2 flux bin). Q5 is not so bright, P4 is even less so. So you want a light with one of these from the R2 bin (which most high end lights using this part will boast having).

MC-E quad emitters - one die with 4 emitters.

Luxeeon

These were the big boys until Cree came along.

Seoul

Luminus

SST-50 SST-90

SSC

P7 quad emitters

Nichia

The "Rigel" is a very small part. (It uses the same format as a 3mm surface mount LED.) Most of the charm is the small form factor. The target market was to be a "flash" for cell phone cameras. Used in the Gerber "Firecracker" and the Silverpoint ST101. This part made its debut in late 2006.

The 5mm Nichia is a 15 cent part used everywhere in cheap keychain flashlights.

Feedback? Questions? Drop me a line!

Tom's Digital Photography Info / tom@mmto.org