Laser Plates

Laser Plates
Glass / plastic sheets before the president spoke?

I was wondering what these small, diagonal, glass or plastic plates on stands were in front of the President / public speaker. I suppose they are a sort of technical anti-diffraction laser-guided? If you look from a certain angle, they are completely gray. These: http://www.cbc.ca/gfx/images/news/photos/2009/01/19/obama-lincoln-cp-w6109957.jpg perhaps acustica?

The teleprompters Added: They are certainly the teleprompters. Http: / / en.wikipedia.org / wiki / File: SOU2007.jpg "In this application, they are called Systems Conference teleprompter. In this case, the reflector is usually a piece of glass with a special partially reflective coating. It is mostly transparent so as not to block the speaker by the audience or cameras. Usually, two of them are set up, one on each side the podium (if there is one), so the speaker can look around the audience and still be able to see one. Except for these aesthetic changes, they work the same way as they do for television. "