A picture of an old HOYA filter container. After seeing a tutorial of this effect on the web, I decided to try it out for myself.
Here's how it works: LCD panel, those with matt finish, give off polarised light. Put another polarizer in front of it, get the angles right, and you’ll darken the screen. Placing a transparent object between the screen and the polarizer scrambles the light so you get the rainbow effects. Neat eh?
I've made a youtube video too, if you were interested.
Hope you like it!