Many of us still keep old LCDs that should have been discarded long time ago. There might be a good reason, however, to refrain from disposing of this obsolete equipment. By following a few simple steps, anyone can turn an old LCD into a privacy monitor with contents visible only to the person wearing a pair of special glasses (also home-built), while anyone else can only see a white surface.
An Instructables' user who goes by the nickname dimovi has described this clever LCD hack. Apart from an old LCD, it also requires paint thinner (or some other solvent), 3D glasses or sunglasses frames, as well as an X-Acto knife. Basically, the secret behind the hack is the polarized film, which is normally used to filter backlight from what's actually visible on the screen.
First, you'll need to dismantle the monitor and cut the shell from the inside, which is made of two layers - polarized and anti-glare. The anti-glare coating needs to be peeled off as it's not needed, while you'll need to save a piece of polarized film - it will serve as lenses for the glasses.
The adhesive from the inside has to be wiped using a solvent before assembling the LCD back. The last step is to create glasses, in which the polarized film is used for lenses.
It's hard to say whether anyone will use this monitor to view NSFW contents on a daily basis, but certainly it can be used to surprise your friends and workmates.
There are of course, easier ways to achieve some privacy like 3M Privacy Filters, which darken the screen while viewed from the side. Sure it's more practical, but then you miss out on the fun of tearing apart your old monitor.
The following video shows the privacy monitor LCD hack in action: