What are the front-runners for the future of mobile displays?

Siemens demonstrated a prototype cellphone with a built-in projector at CeBIT 2005 last week. (Thanks to Thad for the link.)

I’m curious whether this kind of technology will win out in the long run. It’s clear it fills a need — the PDA/cellphone small screen is fine up to a point, but in general we want big screen real estate in a small package, and you just can’t get that with today’s rigid screens. There are a few competing models though, each with their own strengths and weaknesses.

Ordered from most personal & on-the-move to most public &apm; in situ:

  1. Head-mounted displays: good for private information and information on-the-move, bad for showing anything to someone else.
  2. Roll-up or fold-up displays: small when being carried but still gives however much screen real estate you need when you need it.
  3. Projector systems: good for turning any table or wall into a touch-sensitive display, but require a flat light-colored surface and can’t be used on-the-move or privately. Unclear if they could ever be as good resolution as the other options unless you carry your own high-quality screen as well (making it something of a hybrid projector / roll-up display).
  4. Ubiquitous displays: great resolution, requires that you’re somewhere that has accessible displays at your disposal. Can’t be used on-the-move at all and also requires that you trust the infrastructure you’re using.

Of course we might also wind up with several systems and use whatever works best in a given situation, just like we have both laptop and PDAs today. But if one niche winds up being vital (say, everyone needs information while on-the-move so everyone wears an HMD) and if it winds up being good enough for the other niches then that tech will eat the others, just like we’re seeing laptops more and more often being used as desktop-replacements today.