Average Co-Inventor Count = 4.29
ph-index = 3
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. Nippon Telegraph and Telephone Corporation (4 from 5,290 patents)
2. Nitsuko Corporation (4 from 86 patents)
3. Nippon Telegraph and Telephone Public Corporation (1 from 522 patents)
4. Iwasaki Tsushinki Kabushiki Kaisha (1 from 33 patents)
5 patents:
1. D314374 - Key telephone set
2. D309726 - Telephone handset
3. D301578 - Telephone handset
4. D301031 - Key telephone set
5. 4144413 - Rotary telephone dial