Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7168876 | Writing instrument for water-metachromatic members with detachable pen point holder | Akio Nakashima | 2007-01-30 |
| 6953345 | Water-metachromatic cloth sheet, toy set using the same, and writing instrument for water-metachromatic members | Akio Nakashima | 2005-10-11 |