Average Co-Inventor Count = 1.50
ph-index = 2
The patent ph-index is calculated by counting the number of publications for which an author has been cited by other authors at least that same number of times.
Company Filing History:
1. Yamaha Corporation (2 from 5,452 patents)
2 patents:
1. 9449586 - Keyboard device
2. 9406284 - Keyboard device and key unit