One of my friends designed LED signs (static and single color single intensity - it simply displayed a number that's all) for one of those stupid TV lotteries here. They had to be as bright or even more than those for outdoor, as they were next to the "players" and they shine on them directly by their reflectors... if you've been in a TV studio you know what I am talking about.

He used modern superbright red LEDs (quite expensive) with relatively high directivity, and he DID use multiplexing (with some relatively high repeat rate, not to be noticeable by the cameras) as he already had some controllers ready from a previous project and had very short time to hand over the finished signs (only a few days, most of the time soldering the LEDs... :-) ).

Note that the application allowed expensive LEDs, single color (red) static display and high directivity (they were always shot directly from the front). This is not a typical setup for standard LED signs.

Jan Waclawek