the problem is that the screens themselves being used to display the image must be polygonal, not flat, and that the size of each surface must be reduced in size proportional to the distance that the observer is from the "invisible" object. for the object to appear invisible from far away (say 100 meters) is not difficult. a person 6ft would only be viewing the object maybe 2 degree above a person 5ft tall. the image would still have to be shifted accordingly though. this just becomes much harder if the observer is 10ft away. standing on his toes changes the view by 10 degrees. therefore the size of each surface on the polygon would have to be one pixel in size at most. the size of the pixels would be determined by the required resolution which would have to be whatever the maximum resolution the eye can see. were not exactly talking planck length size here but itd have to be pretty small. oled seems promising but there still the issue of glare. well, cost too. i think the largest oled still isnt much more than 15" and around $12k. but let me know if you happen to have a few billion dollars lying around for research. id love to help you spend it.