Average Co-Inventor Count = 3.84
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. Hitachi, Ltd. (2 from 42,517 patents)
2. Hitachi Communication Technologies, Ltd. (2 from 129 patents)
4 patents:
1. 7738642 - Reverse charging system, reverse-charging service control apparatus, call agent and reverse charging method
2. 7352856 - Telephone applicable to PSTN and IP network and call connection control method
3. 6977999 - Reverse charging system, reverse-charging service control apparatus, call agent and reverse charging method
4. 5461517 - Magneto-resistance effect type of recording/reproducing head