Average Co-Inventor Count = 5.83
ph-index = 4
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. Hitachi, Ltd. (4 from 42,508 patents)
4 patents:
1. 6477239 - Sign language telephone device
2. 6181778 - Chronological telephone system
3. 5990878 - Sign language editing apparatus
4. 5734923 - Apparatus for interactively editing and outputting sign language