I've been investigating what IR LEDs Vishay makes to see which would be good for IR pen.

You want a wide angle so if you tilt the pen it still works, but you also want it bright enough.
The wider the angle the light is disbursed over, the less intensity at any point (i.e. the camera)
It's just like spraying a garden hose: on JET all the water goes to one place, but you have to point it.
on spray everything gets wet, but not a lot.
TSAL6400 is ±25° while TSAL6200 is ±10°   ... btw, TSAL7400 is the same as the TSAL6400, but in a clear case.

Another consideration is wavelength of the light (nm) Wiimote can't see light we see or it would have too much "noise" to find the signals. Human vision sees from 400nm to about 760nm. Most of you have been using 940nm LEDs, I know the filter in front of the IR camera blocks to about 800mn, (has anyone measured it's absorbtion spectrum?). The thing is 830 to 890 nm LEDs are available and some are brighter (there is also better quantum efficiency, both in making the light in the LED and absorbing it in the camera), so 850nm and up should be fine. Let me know if anyone knows differently.

Anyway because everyone who isn't making IRpens for Wiimotes is busy lighting up security cameras, ;-)  there are lots of bright IR LEDs, many new to the market:
Here are a few to try in decreasing order of preference: (Get the one you can find as close to the top of the list as you can.)
TSAL6400   T-1¾ 940nm   ±25°    40mW/sr
TSAL7400   T-1¾ 940nm   ±25°    40mW/sr
TSHF5210  T-1¾  890nm   ±22°  180mW/sr
TSHF5410  T-1¾  890nm   ±22°    70mW/sr
TSHF6410  T-1¾  890nm   ±22°    70mW/sr
TSHG6400  T-1¾  850nm  ±22°    70mW/sr
TSHG5510  T-1¾  830nm  ±38°    38mW/sr   Really wide but less bright, good in small room.
TSAL7600   T-1¾ 940nm   ±30°    25-75mW/sr   wide, less bright, good in small room, or with multiple cameras


If you are making a stick with the LED on the back and camera behind you
or to the side, try these surface mount chips, wide smooth beam, but flat top so not good for a pen.

Vishay VSMG3700    850 nm    ±60°    10 mW/sr
Fairchild QEB421      880nm     ±60°         48mW/sr


If you want to do the Johnny Lee tape on your fingers and wave your hands to make music or draw or whatever, you want a source of light that is a narrower beam, and you will need lots of LEDs to make it bright try these:
TSFF6210        870nm      ± 10°          90-180-450       


Forget most of the Lite-On and Everlight LEDs they are too dim, except
Everlight HIR5393C-L223  10mm  850nm  25 deg  150-200 mW/sr
A big 10mm LED that's really bright.

Gavin