GHOST IMAGES are what was on the screen immediately before the current page... residual leftovers from the polarised ink... yes? well.... (this is the kicker!!!)... the inverted screen has this purpose... the ghost of the page you are reading is the background of that page !!! i.e. the last page was the background of that current page, so the whole background of the current page is just one big ghost !!! (ingenius IMHO)
So... it flashes an inverted version of the new page (the new ghost, as opposed to the previous page of text being the ghost), and then it builds up the real current page with a couple of gradual refreshes
It's the only way that we can read a page without seeing ghost from the previous page of text... the device completely eliminates the previous page's text from the equation, so that all there is, is the current page of text, and the background of the current page of text to use as a ghost... I hope the person that came up with the idea got paid a lot... as I said before... ingenius