Which a patent does too, just with a license or 20 years later. It keeps people from reinventing the wheel and gives the disclosure rights even if they didn't have the infrastructure to create or monetize on their own. This isn't one of those nefarious software patents where the whole thing would be obsolete within 5 years, this is LED books, which simply becomes more feasible as transistor sizes shrink and battery technology improves, perfect for a 20 year exclusivity period before falling into the public domain where it can be vastly more practical to create in 2033.