Here's a simpler, less sci-fi approach that I could imagine a team of engineering students pullin goff:

Existing electronic Braille technology lifts a few pins up and down to recreate the Braille characters, and can also show simple lines.

If you expanded it to be a 500wide by 300 high block of pins you would have a Braille monitor that could be compatible with any home computer!

(This will help you visualize, only the pins would be denser and more numerous)
http://www.gadgetshop.com/media/gadgetshop/products/ProductGalleryImage1/276402.jpg

Now, imagine a grayscale monitor (a.k.a. black and white) that represented white-grey-black by using deep-medium-shallow. For this example, I’ve assumed we have a crude prototype that can only make four shades of grey:

http://img152.imagevenue.com/img.php?image=49848_Braille_Monitor-web_122_865lo.jpg#

This idea only involves combining existing devices, including:

Braille fonts option on Web browsers
(easy, took me five minutes to install and use)
http://braillefont.com/

A way to push pins without bulky breakable mechanics
(this is a large homemade demo of electromagnetic repulsion, but you get the idea)
http://www.youtube.com/watch?v=9K6THx2g4E8&feature=related

A way to make a touch screen that will only acknowledge touch when you want it to:




Note to Engineers:
Not only would you be a hero to the visually impaired, but you could make a large scale version and have the coolest dorm-window display ever!