ok, great, someone has invented an automatic blind closer, but with motors and standard hanging blinds.
why not make it cool? how about at a touch of a button, a window you could see thru a second ago becomes milky white, or black?
using the principles of the polarization of light, you could do this...have you ever bought a pair of polarized sunglasses? notice how everything appears crisper, and glare is eliminated? that's because the sunglasses are only letting thru light that is polarized in one direction (effectively blocking the other polarizations - the ones that cause glare, etc.).
now imagine you have another pair of polarized sunglasses. if you rotate this pair 90 degrees to the first pair, as you watch from the back (thru both pairs of sunglasses), your view will become dimmer and dimmer, until you no light passes thru!
(i've actually never tried this experiment with 2 pairs of polarized sunglasses, but 2 polarizer filters for a camera would work just as well).
now, for a window,
you could do this mechanically by rotating 2 polarizers against each other, it requires large sheet polarizers and circular windows, but it could be done, but you still have to mess around with motors, and it would take time to rotate, but maybe that we'd like that effect.
an alternate (and much cooler) idea may be a bit expensive, but if people are buying those huge screens for digital art, maybe there's a market.
there are devices called LCD liquid polarizers. for example, http://www.meadowlark.com/catalog/Liqui ... qcrys1.htm
apply a certain voltage, and walla, you have polarization without mechanical rotation. on this site, these types have max "see-thru" diamters of 1.7 inches (that is the spec called clear aperture).
i think these devices are in the $thousands range, but you could build one now if you had the resources. but you only get a 1.7 inch window. someone could develop a pane of glass, or even bay windows, with this method.
i think it hasn't been done since the liquid crystal is sandwiched in between 2 layers of glass, and larger glass size create inconsistencies in the separation distance, which screws up the polarization, but i'm dampening my own idea. shame. the orders would pour in. one, because, it be nice to have no cracks of light, like blinds give you in your eye. two, another advantage, is adjustable brightness. three, a high cool factor. touch a button, instant darkness, or light!
reward for me: 3 6x10 foot bay windows, or enough panes to make that many.