Wacom released the SD tablet in 1987. Their patent on inductively-powered styluses should have expired by now. (Back then, US patents were valid for 17 years

Wacom released the SD tablet in 1987. Their patent on inductively-powered styluses should have expired by now. (Back then, US patents were valid for 17 years from issue date, but the backlog was also much shorter.) I know that N-trig used to make an inductively-powered stylus about 5 years ago, but for whatever reason, they switched to batteries.