The other day I was thinking about the ambient-light contrast problem, and I hit upon an interesting idea. I ran a quick search and it turns out HP's engineers beat me to it by about three years.
Basically the idea is a screen with a thin layer of pixels (grayscale LCD) embedded into it or overlaid on it, whose brightness is individually controlled to improve the contrast of the projected image.
Anybody know if something like this really exists? I suppose it would be pretty heavy, not to mention staggeringly expensive (considering the insane prices everyone charges today for fancy bits of cloth). Talk about a challenge for the guys in the DIY forum...
A projection screen is provided that includes a display surface having a plurality of elements. Each element has an optical property that is responsive to an appropriate applied voltage. The display surface may be configured so that the optical property of each element may be coordinated with the projected image.