I often change bulbs in LCD projectors. The high-pressure bulbs run so hot they require elaborate cooling fans, yet still shorten the life of the rest of the projector. Picture quality degrades as they near end-of-life, and a new bulb (often with less than 1,000 hours on it) costs $350.
Various LED arrays stacked with optical columnators come to mind, but here’s another idea I like a lot: the microwave lightbulb. Far more efficient (and thus cooler-running) and it wouldn’t die. It would vastly improve the economical practicality of classroom projection systems. It could even be used in other applications like room lighting.
(from Pure Pedantry)
I think one reason why LEDs haven’t been used yet in projectors is they have a hard time getting bright enough for that application.
But the microwave lightbulb may have a shot. Very interesting idea indeed!