Average Co-Inventor Count = 14.01
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 42,508 patents)
2. Kokusai Electric Co., Ltd. (2 from 153 patents)
2 patents:
1. 5838770 - Portable telephone system
2. 5579370 - Portable telephone system