SACD - the fall and rise

摘要

As a rule of thumb (there are variations) patents last for 20 years. Beyond that, anyone can use your invention and they no longer have to pay you for the privilege. So the canny inventor uses some of that time, and some of the patent revenue, to come up with something better to patent in its turn and keep the licence fees rolling in. That's what Philips and Sony hoped to do with Super Audio Compact Disc.