Lenovo ThinkPad Privacy Filters utilize the patented 3M microlouver privacy technology to darken the screen at specific angles so as to block the vision of wandering eyes from viewing your screen while you work. This is a key benefit to companies as it provides the first line of defense against visual hacking protecting private information from being hacked by on lookers. Privacy filters also reduce glare from bright backlight panels and overhead lights though that's not its primary function. Another function is that privacy filters guards and protects your screen from scratches and smears keeping your monitor screens safe from unwanted destruction.