LCD screen only visible through your glases. This is a simple trick, release the LCD matrix of the plastic shell, with a sharp knife carve the polarizing film, carefully wipe the glass panel and reassemble the monitor. Gently stick the film tape to the glasses that you extracted from the monitor. Now you got your self a unique private view.
Warning: Staring at blank screen with your sunglasses on could get you fired!
Source: Private Screen