You might find that the two terminal, dual LED packages with inverse-parallel
LEDs produce a more even color of amber.  This is because the two die are
closer, since they connect to the same wires.  The two die on your LED are
positioned much further apart, and since neither die is in the focal point of
the LED package, they will always be visible seperately.  You might also try
looking for an LED which has the three legs in a triangle pattern, rather than
in a traight line.  They will have die which are slightly closer.

In the end, the only way you would be able to get your particular LED to produce
a nice amber is by using a lens which takes the light from each LED and focuses
it onto one spot (ie, it's not worth it...).  You will only have some small
success with cheaper light pipes, since they will not mix the colors.  You could
go with a bundle of fiberoptics which are mixed very carefully one one end.

You could redesign your project to use two seperate leds, and point them at a
flat diffuse panel so their lenses focus at the same spot.  Use a mask on the
panel, and you'll end up with a very smart looking flat light on the panel.

Unless you need perfectly blended light, you probably ought to try the LEDs that
are inverse parallal in the same package.  They will give you a better blend.
Not perfect, but enough that most people won't be able to tell.

-Adam

Andrew Kunz wrote:
>
> I need to generate Red, Amber-ish, and Green from a single LED body (standard
> T1.75 size).
>
> I am limited to a common-cathode device with two anodes to select the desired
> color.
>
> The P391 from Digi-Key doesn't blend the colors well when both LEDs are turned
> on, it's obviously a red and a green LED in the same package.
>
> Anybody have any experience with LEDs that _will_ work well?  Vendors?
>
> Thanks.
>
> Andy