I would love to play with pico projector modules like these:
http://www.syndiant.com/Default.aspx
I’ll admit I have no idea what would be needed in terms of optics, casing or processing power.
Very non trivial, this stuff is all very bleeding edge. There are very few comercial products yet because the price performance is still not quite there and there is a lot of cash going into the r&d (I used to work for a company that explored the area 24 months back).
Apparently, a few days ago, you could buy [this pico projector for $119 (that’s kind of what triggered my interest). Now that’s still a bit above my budget for “just taking it apart”, but it’s getting there.
I am also very curious to see how the laser pico projectors works. From what I’ve read, laser projectors don’t need a focusing lens, which must make optics simpler. And if I stuck to short distances, and to a single color (so I could use a [cheap red laser), I wonder how small the whole projection assembly would end up being.](http://www.sparkfun.com/commerce/product_info.php?products_id=594)](Amazon.com)
If I remember correctly there were two options for the laser based system. One was basicaly a scaning mirror in silicon. There were interesting safty issues with this one if the mirror stoped scanning… The other was using an LCOS and you generate the image by setting up the apropriate defraction grating on the LCOS and the interferance pattern was your image. The processing to work out the defraction patern for a given image was huge but theoreticaly this was the best bet for high efficentcy in terms of lumens / watt or so I was told.
Size wise all the work is aimed to getting somthing small enough and power efficent enough for a mobile phone.