Average Co-Inventor Count = 2.67
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. D453558 - Kerosene-fired room heater
2. D306722 - Television receiver
3. D271974 - Television receiver
4. D269676 - Television receiver